AUTOMATIC TRACTION ASSISTANCE SYSTEM BASED ON STEERING ANGLE
OF VEHICLE
FIELD OF INVENTION
[001] The present invention relates to a traction assistance or control system, and more particularly an automatic traction assistance system, which controls the air pressure of the ride air springs of lift axle or air suspension for reducing shoulder scrub of tire of a multi-axle commercial vehicle.
BACKGROUND OF INVENTION
[002] Now a days, original equipments manufacturers (OEM) develop multi-axle commercial vehicles to satisfy customers requirements. The road system is being improved in the developing countries. However, the operating cost (cost of vehicle operator/driver) and unavailability of operator are being increased significantly. Therefore, original equipments manufacturers are more focusing on developing heavy multi-axle commercial vehicles (such as heavy duty rigid trucks) having maximum allowable load limit in the road, so that vehicle owners can earn more income per day using these vehicles. In addition, as the competition is high in the market, original equipments manufacturers focus on developing new heavy duty vehicles having 10x2 and 10x4 configurations for haulage and tipping application.
[003] Generally, in order to increase the load carrying capacity of the multi-axle commercial vehicles, auxiliary axles are added either in front of the drive axle or rear side of the drive axle. The auxiliary axle is commonly an air suspension system and is lifted in un-laden condition, which is therefore called as lift axle. If the auxiliary axle is located in front, of the drive axle, then it is called as pusher lift axle. If the auxiliary axle is located at the rear side of the drive axle, then it is called as tag lift axle.
[004] FIGS. 1(a)-1(d) show side and top view of a commercial multi-axle vehicle (MAV) having configuration of 10x2 or 10x4 with a pusher lift axle (1), in accordance with the prior art.

Similarly, the commercial multi-axle vehicle having configuration of 10x4 with a tag lift axle (not shown) is being developed in Korea, Australia etc. Such heavy vehicle is provided with the pusher lift axle that is composed of dual tire (6) in both the sides, where such heavy vehicles are manufactured in developed countries such as USA and Australia. The heavy commercial vehicle has twin front axles (2a, 2b), a pusher lift axle (1) and two rear axles (3a, 3b). The twin front axles (2a, 2b) are equipped with conventional leaf spring suspensions and the rear axles (3a, 3b) are equipped with a tandem rear leaf spring suspension, which is either (i) non-reactive suspension (NRS, 7) or (ii) slipper end suspension (8) or (iii) bogie suspension (9). The lift axle (1) is either located in pusher location, i.e. in front of first drive axle (3a) or tag location (not shown), i.e. rear side of the drive axle (3a).
[005] The front axles (2a, 2b) are namely first front axle (2a) and second front axle (2b). The rear axles (3a, 3b) are namely drive axle (3a) and dummy axle (3b). The pusher lift axle (1) is a non-steer parallelogram air suspension and has dual tires (6). The lift axle (1) is located in front of the conventional tandem rear leaf spring suspension in a well-known manner. The front axles (2a, 2b) are steered by power steering and all the tandem rear axles (3a, 3b) are non-steer axles. Each front axle has single tire (5) on each side, whereas each rear axle (3a, 3b) has dual tires (6) on each side. The pusher lift axle (1) is assembled with dual tires (6) on each side. Therefore, the present commercial multi-axle vehicles can carry maximum allowable load in developing countries.
[006] FIGS. 2(a)-2(d) each illustrates details of the pusher lift axle (1) mounted in front of leaf spring suspensions, in accordance with the prior art. The front axles, i.e. first front axle (2a) and second front axle (2b), are attached to the chassis frame (4) through the conventional multi-leaf spring suspension (not shown) in a mechanical means (FIG. 1). The tandem rear leaf spring suspensions either NRS suspension (7, as shown in FJG. 2a) or slipper end balancer beam suspension (8, as shown in FIG. 2b) or bogie inverted leaf spring suspension (9, as shown in FIG. 2c). The pusher lift axle (1) is an air suspension (as shown in FIG. 2d), and is attached to the chassis frame (4) between the second front axles (2b) and the drive axle (3a).

[007] In FIG. 2(d), the details of the pusher lift axle (1) is illustrated and is composed of a pair of load air springs,i.e. ride air springs (10), a pair of lift air springs (11), a pair of top control arms (12) and a pair of lower control arms (13). In addition, the pusher lift axle (1) has two tires (6) at each side of the lift axle. FIG. 3 illustrates details of a unique automatic lift axle control system, in accordance with the prior art. The automatic lift axle control system is used to operate the lift axle in laden and unladen condition, in which, a dual load sensing valves are used. The design of pusher lift axle (1) and the automatic lift axle control system are not a part of present invention. Therefore, the details are not described hereafter. In unladen condition, the load or ride air springs (10) are deflated and the lift air springs (11) are inflated in the lift axle (1), such that the lift axle is lifted-off from the road surface and is held along with its tires (6) at a desired height from the road surface.
[008] As the pusher lift axle (1) has dual tires (6) on each side, the commercial multi-axle vehicle can carry maximum allowable load in developing countries. However, when the MAV vehicle is operated in a sever turn or sever undulated road, a lot of sever tire scrub problem is observed in the 10x4 or 10x2 MAV vehicle having non-steer pusher lift axle (I) having dual tire (6) on each side. In particular, as three non-steer axles are mounted at the rear side of the vehicle, the tires in the pusher lift axle (1) and tag axle (3b) are subjected to sever cornering forces when the vehicle experiences the sever turn. Therefore, the tires at the pusher lift axle and tag axle are subjected to sever tire scrubbing, which leads to a shoulder scrub in the tires fitted in the pusher lift axie (1) and the tag axle (3b) when the vehicle experiences the sever turn. Therefore, the life of the tire is significantly and drastically reduced.
[009] Therefore, in the multi-axle vehicle, it is highly necessary to to minimize the shoulder scrub in the tire. In some prior art approaches, a manual traction assistance system is being conventionally used in the multi-axle vehicles, such as multi-axle coach (bus) having two rear axles and few trucks having tandem axles suspension (two rear axles). In prior art, a manual operated traction assistance system is provided in multi-axle coach, tractor trailer 6x2 TT and multi-axle truck having 6x2 configurations with tag non-steer lift axle. In these vehicles, the operator (i.e. driver) has to operate (i.e. switch on) the switch manually when the vehicle is experienced a sever turn in undulated roads. Thereby, the ride air springs of the auxiliary

suspension are deflated for a while and inflated automatically in a pre-described time or speed of the vehicle. When deflating the ride air springs, the reaction load on the auxiliary axle is minimized to the self weight of the axle assembly. The same operation is followed when the vehicle is in reverse condition also. Thereby, the load on the pusher or tag axle is transferred to the remaining axles for a limited period. It greatly helps in minimizing tires shoulder scrub, and increasing maneuverability and traction of the vehicle.
[0010] In general, the operator follows the manual operation of the switch very rarely in these manual traction assistance systems. Further, the operator forgets to manually operate the switch in most of the time especially during sever turn due to the urgency of driving in the traffic maneuver, vehicle reverse condition, undulated road and slippery road, etc. Therefore, practically, the operator (driver) could not operate the manual switch properly. If the operator change occurs, the new operator should learn the operation principle to reduce the tire scrub and maneuver of the vehicle. Most specifically, in developing countries such as India, Pakistan China, such manual operating system is not preferable. As the developing countries such as India, Pakistan China, etc have undulated roads and sever turned roads, the operator cannot operate the vehicle properly with operating such switch manually. In addition, as the driver education is less compared to the developing countries, such manual operating traction assistance system is not preferable.
[0011] The conventional manual operated traction assistance system consists of many electrical and electronics parts, converters etc. Therefore, the cost of the manufacturing and maintenance cost are remarkably high. From the overall study, the conventional available manual traction assistance system is not desirable solution for hauling, i.e. effective traction assistance to the vehicle. In respect of the conventional approaches, the operation of manual switch traction assistance system does not provide complete solution to minimize tires shoulder scrub, maneuverability and traction of the vehicle when the multi-axle vehicle experiences sever turn or sever undulated road. Thus, the conventional available manual traction assistance system is not desirable solution to overcome the above mentioned drawbacks and disadvantages.

[0012] Therefore, it is necessary to provide a unique automatic traction assistance system to overcome the above mentioned drawbacks and disadvantages, i.e. minimizing tires shoulder scrub and facilitating a better drivability (maneuverability) when the vehicle is operated during sever turn or sever undulated road. Further, such automatic traction assistance or control system is essentially required to provide high performance in the undulated road and abused condition (rugged operating condition). In addition, it should be economical for both OEM (i.e., low over all production cost) and user (i.e., less investment, operating and maintenance cost).
OBJECT OF THE INVENTION
[0013] A primary object of the present invention is to provide an automatic traction assistance system for a multi-axle commercial vehicle having non-steer or steer lift axle, which is automatically operated by a steering mechanism based on a steering angle of the vehicle during
sever turn.
[0014] Another object of the present invention is to provide an automatic traction assistance system for a multi-axle commercial vehicle having lift axle, which is capable of increasing maneuverability and traction in the drive axle when the vehicle experiences a sever turn.
[0015] Another object of the present invention is to provide an automatic traction assistance system, which is capable of enhancing life of tire by reducing shoulder scrub in the tire.[017] Another object of the present invention is to provide an automatic traction assistance system, which is economical for both OEMs (i.e. low over all production cost) and users (i.e. less investment, operating and maintenance cost).
[0016] Another object of the present invention is to provide an automatic traction assistance system, which can be used for both haulage and tipper application.
SUMMARY OF THE INVENTION
[0017] An automatic traction assistance system based on steering angle of the vehicle is disclosed for a commercial multi-axle vehicle (5) having a steer or non-steer lift axle. This

automatic traction assistance or control system works based on the movement of a steering mechanism or system of the vehicle, i.e. rotation of a steering wheel at a critical steering angle of the vehicle. Especially, it controls air pressure of ride air springs (i.e., load air springs) of the lift axle based on the critical steering angle of the vehicle, such that when the vehicle experiences the critical steering angle, the ride air springs of the lift axle are fully deflated or partially deflated to lift-off the lift axle along with the tires from the road surface. Thus, the automatic traction assistance system is automatically operated by the steering mechanism without any necessity of manual operations by the operator (driver), which increases maneuverability and traction in the drive axle when the vehicle experiences the sever turn, and thus it enhances life of tire by reducing shoulder scrub in the rear tires of the vehicle.
[0018] According to the first embodiment of the present invention to achieve the object of the invention, an automatic traction assistance system is operated by the steering mechanism based on the steering angle of the vehicle having twin steer axles and a lift axle that is arranged with a pair of ride air springs and a pair of lift air springs. The automatic traction assistance system, in accordance with an exemplary first embodiment of the present invention, consists of a leveling valve, a pilot operated direction control valve DCV1, a electrical operated direction control valve DCV2, a swinging bracket assembly, a pair of linkages assemblies (namely, valve linkage assembly, steering linkage assembly), traction assistance electrical switch (TS), C clamp or bracket assembly and an automatic lift axle control system. Accordance to the first embodiment of the present invention, the ride air springs are fully deflated when the vehicle is experienced the critical steering angle. In this system, the first direction control valve (DCV1) is pneumatically operated to deflate the ride air springs of the lift axle when the vehicle reaches the desired or critical steering angle during sever turn. The second direction control valve (DCV2) is electrically connected and operated by a traction switch (TS) to provide a pneumatic signal to the first DCV1 in order to supply compressed air to the ride air springs or to deflate the lift air springs of the lift axle. The leveling valve (LV) is secured to a vehicle frame and pivotally attached to a tie rod link of the steering mechanism for controlling the first DCV1 in order to deflate the ride air springs or supply compressed air from a primary air tank to the ride air springs. The linkage assembly or mechanism is secured on a swinging bracket assembly for pivotally connecting a lever of the leveling valve and the tie rod link connected between first and

second drop arms of the steering mechanism. Further, a quick release valve (QRV1) is connected to the ride air springs to rapidly exhaust the air from the ride air springs, which deflates the ride air springs to lift the lift axle.
[0019] The leveling valve is secured to a valve bracket attached to the vehicle frame in such a way that the lever of the leveling valve is connected to one end of the swinging bracket assembly through the valve linkage assembly, where other end of the swinging bracket assembly is pivotaily connected with the valve bracket. The linkage mechanism is connected to the swinging bracket assembly and the steering linkage assembly that is connected to the tie rod link through the clamp assembly. The leveling valve is fluidly connected in between the primary air tank and the second DCV2 such that the leveling valve controls the operation of the first DCVI to fully deflate the ride air springs by supplying compressed air to the ride air springs through the second DCV2.
[0020] The iever of the leveling valve is operated through the linkage mechanism according to the movement of steering mechanism for controlling air pressure of the ride air springs of the lift axle, which fully deflates the ride air springs with respect to the desired steering angle attained by the vehicle during sever turn. The second DCV2 is fluidly connected between the first DCV1 and the leveling valve, and electrically connected with an ignition switch through the traction switch. The traction switch is electrically connected between a vehicle battery through the ignition switch and an electrical terminal of a solenoid of the second DCV2 in order to activate or deactivate the second DCV2. The quick release valve is fluidly connected between the first DCV1 and the ride air springs such that the operation of quick release valve is controlled by the leveling valve through the second DCV2 in order to fully deflate the ride air springs to lift the lift axle when the vehicle reaches the desired steering angle during sever turn. The desired steering angle of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.
[0021] According to second embodiment of the present invention to achieve the object of the invention, an automatic traction assistance system is operated by the steering mechanism based on the steering angle of the vehicle having twin steer axles and a lift axle that is arranged with a

pair of ride air springs and a pair of lift air springs. The automatic traction assistance system, in accordance with an exemplary second embodiment of the present invention, is similar to the first embodiment of the present invention, in which the ride air springs are partially deflated instead of fully deflate the air springs when the vehicle is experienced the critical steering angle. In this system, a first direction control valve (DCV1) is pneumatically operated to deflate the ride air springs of the lift axle when the vehicle reaches a desired or critical steering angle during sever turn. A second direction control valve (DCV2) is electrically connected and operated by a traction switch (TS) to provide a pneumatic signal to the first DCV1 in order to supply compressed air to the ride air springs or to deflate the lift air springs of the lift axle. A leveling valve (LV) is secured to a vehicle frame and pivotally attached to a tie rod link of the steering mechanism for controlling the first DCV1 in order to deflate the ride air springs or supply compressed air from a primary air tank to the ride air springs. A linkage mechanism is secured on a swinging bracket assembly for pivotally connecting a lever of the leveling valve and the tie rod link connected between first and second drop arms of the steering mechanism. A pressure limiting valve (PLV) is to limit air pressure in the ride air springs for partial deflation of the ride air springs when the vehicle reaches the desired steering angle during sever turn. A first quick release valve (QRV1) is connected to the ride air springs to rapidly exhaust the air from the ride air springs, which deflates the ride air springs to lift the lift axle. A second quick release valve (QRV2) connected between the pressure limiting valve and the first DCV1 to exhaust air from an exhaust line extended from the first DCV1.
[0022] The pressure limiting valve is fluidly connected between the primary air tank and an inlet port of the first DCV1 through the second QRV2. When the vehicle reaches the desired steering angle during sever turn, the leveling valve interrupts the supply of compressed air to the ride air springs through the second DCV2 and simultaneously, the pressure limiting valve controls the second QRV2 and the first DCV1 such that air pressure is maintained in the ride air springs for partially deflating the ride air springs. The leveling valve is fluidly connected in between the primary air tank and the second DCV2 such that the leveling valve controls the operation of the first DCVI to fully or partially deflate the ride air springs by supplying compressed air to the ride air springs through the second DCV2. The lever of the leveling valve is operated through the linkage mechanism according to the movement of steering mechanism for controlling air

pressure of the ride air springs of the lift axle, which fully or partially deflates the ride air springs with respect to the desired steering angle attained by the vehicle during sever turn. The leveling valve is secured to a valve bracket attached to the vehicle frame in such a way that the lever of the leveling valve is connected to one end of the swinging bracket assembly through a valve linkage assembly, where other end of the swinging bracket assembly is pivotally connected with the valve bracket. The linkage mechanism is connected to the swinging bracket assembly and a steering linkage assembly that is connected to the tie rod link through a clamp assembly. The desired steering angle of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.
[0023] According to third embodiment of the present invention to achieve the object of the invention, an automatic traction assistance system is operated by the steering mechanism based on the steering angle of the vehicle having twin steer axles and a lift axle that is arranged with a pair of ride air springs and a pair of lift air springs. The automatic traction assistance system, in accordance with an exemplary third embodiment of the present invention, is similar to the first and second embodiments of the present invention, in which a leveling valve is secured to a vehicle frame and pivotally attached to either first or second drop arms of the steering mechanism of the vehicle instead of the tie rod link. According to the third embodiments of the present invention, when the vehicle experiences the critical steering angle, the ride air springs are fully deflated and/or partially deflated. In this system, a first direction control valve (DCV1) is pneumatically operated to deflate the ride air springs of the lift axle when the vehicle reaches a desired steering angle during sever turn. A second direction control valve (DCV2) is electrically connected and operated by a traction switch (TS) to provide a pneumatic signal to the first DCV1 in order to supply compressed air to the ride air springs or to deflate the lift air springs of the lift axle. The leveling valve (LV) is secured to the vehicle frame and pivotally connected with at least one of the first and second drop arms of the steering mechanism for controlling the first DCV1 in order to deflate the ride air springs or supply compressed air from a primary air tank to the ride air springs. A linkage mechanism is secured on a swinging bracket assembly and pivotally connected between a lever of the leveling valve and the first drop arm or second drop arm of the steering mechanism. A pressure limiting valve (PLV) is to limit air pressure in the ride air springs for partial deflation of the ride air springs when the vehicle reaches the desired

steering angle during sever turn. A first quick release valve (QRV1) is connected to the ride air springs to rapidly exhaust the air from the ride air springs, which deflates the ride air springs to lift the lift axle. A second quick release valve (QRV2) is connected between the pressure limiting valve and the first DCV1 to exhaust air from an exhaust line extended from the first DCV1.
[0024] The leveling valve is pivotally connected with the first drop arm or the second drop arm through the linkage mechanism and the swinging bracket assembly. The leveling valve is secured to a valve bracket attached to the vehicle frame in such a way that the lever of the leveling valve is connected to one end of the swinging bracket assembly through a valve linkage assembly, where other end of the swinging bracket assembly is pivotally connected with the valve bracket. The linkage mechanism is connected to the swinging bracket assembly that is connected to the first drop arm or second drop arm of the steering mechanism through a steering linkage assembly. The lever of the leveling valve is operated through the linkage mechanism according to the movement of the first drop arm or second drop arm of the steering mechanism such that the leveling valve controls the operation of the first DCV1 to fully or partially deflate the ride air springs by supplying compressed air to the ride air springs through the second DCV2 with respect to the desired steering angle attained by the vehicle during sever turn.
[0025] According to fourth embodiment of the present invention to achieve the object of the invention, an automatic traction assistance system is operated by the steering mechanism based on the steering angle of the vehicle having twin steer axles and a lift axle that is arranged with a pair of ride air springs and a pair of lift air springs. The automatic traction assistance system, in accordance with the fourth embodiment of the present invention, is similar to the first and second embodiments of the present invention, in which a critical steering angle valve (replacing the leveling valve) is secured to a vehicle frame and pivotally attached to a tie rod link of the steering mechanism of the vehicle. The critical steering angle valve controls the operation of the ride air springs, such that when the vehicle experiences a critical steering angle, the ride air springs are fully deflated and/or partially deflated. In this system, a first direction control valve (DCV1) is pneumatically operated to deflate the ride air springs of the lift axle when the vehicle reaches the desired or critical steering angle during sever turn. A second direction control valve (DCV2) is electrically connected and operated by a traction switch (TS) to provide a pneumatic

signal to the first DCV1 in order to supply compressed air to the ride air springs or to deflate the lift air springs of the lift axle. The critical steering angle valve is secured to the vehicle frame and pivotally attached to the tie rod link of the steering mechanism for controlling the first DCV1 in order to deflate the ride air springs or supply compressed air from a primary air tank to the ride air springs. A pressure limiting valve (PLV) is to limit air pressure in the ride air springs for partial deflation of the ride air springs when the vehicle reaches the desired steering angle during sever turn. A first quick release valve (QRV1) is connected to the ride air springs to rapidly exhaust the air from the ride air springs, which deflates the ride air springs to lift the lift axle. A second quick release valve (QRV2) is connected between the pressure limiting valve and the first DCVI to exhaust air from an exhaust line extended from the first DCV1.
[0026] The critical steering angle valve has a lever that is pivotally attached to the tie rod link connected between first and second drop arms of the steering mechanism through a linkage assembly and a bracket assembly. The lever of the critical steering angle valve is operated through the linkage assembly according to the movement of tie rod link of the steering mechanism for controlling air pressure of the ride air springs of the lift axle, which fully or partially deflates the ride air springs with respect to the desired steering angle attained by the vehicle during sever turn. The critical steering angle valve is secured to a valve bracket attached to the vehicle frame in such a way that the lever of the critical steering angle valve is pivotally connected to one end of the linkage assembly, where other end of the linkage assembly is connected to the tie rod link through the bracket assembly. The critical steering angle valve is fluidly connected in between the primary air tank and the second DCV2 such that the critical steering angle valve controls the operation of the first DCV1 to fully or partially deflate the ride air springs by supplying compressed air to the ride air springs through the second DCV2. The desired steering angle of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.
[0027] According to fifth embodiment of the present invention to achieve the object of the invention, an automatic traction assistance system is operated by the steering mechanism based on the steering angle of the vehicle having twin steer axles and a lift axle that is arranged with a pair of ride air springs and a pair of lift air springs. The automatic traction assistance system, in

accordance with the fifth embodiment of the present invention, is similar to the fourth embodiment of the present invention, in which a critical steering angle valve is secured to a vehicle frame and pivotally attached to either first or second drop arms of the steering mechanism of the vehicle instead of directly to a tie rod link. The critical steering angle valve controls the operation of the ride air springs, such that when the vehicle experiences a desired or critical steering angle, the air springs are fully deflated and/or partially deflated. In this system, a first direction control valve (DCV1) is pneumatically operated to deflate the ride air springs of the lift axle when the vehicle reaches the desired steering angle during sever turn. A second direction control valve (DCV2) is electrically connected and operated by a traction switch (TS) to provide a pneumatic signal to the first DCV1 in order to supply compressed air to the ride air springs or to deflate the lift air springs of the lift axle. The critical steering angle valve is secured to the vehicle frame and pivotally connected with at least one of the first and second drop arms of the steering mechanism for controlling the first DCV1 in order to deflate the ride air springs or supply compressed air from a primary air tank to the ride air springs. A pressure limiting valve (PLV) is to limit air pressure in the ride air springs for partial deflation of the ride air springs when the vehicle reaches the desired steering angle during sever turn. A first quick release valve (QRV1) is connected to the ride air springs to rapidly exhaust the air from the ride air springs, which deflates the ride air springs to lift the lift axle. A second quick release valve (QRV2) is connected between the pressure limiting valve and the first DCV1 to exhaust air from an exhaust line extended from the first DCV1.
[0028] The critical steering angle valve is secured to a valve bracket attached to the vehicle frame in such a way that the lever of the critical steering angle valve is pivotally attached to the first drop arm or the second drop arm through a linkage assembly. The fever of the critical steering angle valve is operated through the linkage assembly according to the movement of the first drop arm or second drop arm of the steering mechanism for controlling air pressure of the ride air springs of the lift axle, which fully or partially deflates the ride air springs with respect to the desired steering angle attained by the vehicle during sever turn. The critical steering angle valve is fluidly connected in between the primary air tank and the second DCV2 such that the critical steering angle valve controls the operation of the first DCV1 to fully or partially deflate the ride air springs by supplying compressed air to the ride air springs through the second DCV2.

The desired steering angle of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0029] The objects and advantages of the present invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings, in which:
[0030] FIGS. l(a)-l(d) show side and top view of a commercial multi-axle vehicle (MAV) having configuration of 10x2 or 10x4 with a pusher lift axle, in accordance with the prior art;
[0031] FIGS. 2(a)-2(d) each illustrates details of the pusher lift axle mounted in front of leaf spring suspensions, in accordance with the prior art;
[0032] FIG. 3 illustrates details of a unique automatic lift axle control system, in accordance with the prior art;
[0033] FIG. 4 illustrates a schematic view of an automatic traction assistance system based on a steering angle of a vehicle, in accordance with an exemplary first embodiment of the present invention;
[0034] FIG. 5 illustrates a schematic view of an automatic traction assistance system based on a steering angle of a vehicle, in accordance with an exemplary second embodiment of the present invention;
[0035] FIGS. 6(a) and 6(b) illustrate a schematic view of a leveling valve and a linkage mechanism attached with a steering mechanism of a heavy duty multi-axle vehicle, in accordance with the present invention;
[0036] FIGS. 7(a) and 7(b) illustrate details of critical steering angle and maximum steering angle (max. cut angle) of tire of the commercial multi-axle vehicle at left-hand (LIT) turn and right-hand (RH) turn, respectively, in accordance with all exemplary embodiments of the present
invention;

[0037] FIG. 8 illustrates details of the automatic traction assistance system fitted in a vehicle frame and steering linkages of the vehicle having twin front axle, in accordance with the first and second embodiments of the present invention;
[0038] FIG. 9 illustrates operation details of the leveling valve, the linkage mechanism and the steering linkage assembly, in accordance with the first and second embodiments of the present invention;
[0039] FIG. 10 illustrates an exploded view of the leveling valve, the linkage mechanism and the steering linkage assembly, in accordance with the first and second embodiments of the present invention;
[0040] FIG. 11 illustrates an exploded view of a swinging bracket assembly, in accordance with the first, second and third embodiments of the present invention;
[0041] FIG. 12 illustrates a detailed view of a valve bracket, in accordance with the present invention;
[0042] FIG. 13 illustrates a detailed view of a C clamp or bracket assembly, in accordance with
the present invention;
[0043] FIG. 14(a) and 14(b) illustrate a schematic view of an automatic traction assistance system based on a steering angle of a vehicle, in accordance with an exemplary third embodiment of the present invention;
[0044] FIG. 15 illustrates details of a leveling valve and a linkage mechanism attached with a first drop arm of a steering mechanism, in accordance with an exemplary third embodiment of
the present invention;
[0045] FIG. 16 illustrates operation details of the leveling valve, the linkage mechanism and a steering linkage assembly when the first drop arm is oscillated, in accordance with the third
embodiment of the present invention;

[0046] FIG. 17(a) illustrates a schematic view of an automatic traction assistance system based on a steering angle of a vehicle, in accordance with an exemplary fourth embodiment of the
present invention;
[0047] FIG. 17b illustrates working principle of a critical steering angle valve with respect to lever angle (movement), in accordance with the exemplary fourth embodiment of the present
invention;
[0048] FIG. 18 illustrates details of the critical steering angle valve and a linkage mechanism attached with a steering mechanism of a heavy duty multi-axle vehicle, in accordance with an exemplary fourth embodiment of the present invention;
[0049] FIG. 19 illustrates operation details of the critical steering angle valve when a tie rod link is moved in the fore and apt direction, in accordance with the fourth embodiment of the present
invention;
[0050] FIG. 20(a) and 20(b) illustrate a schematic view of an automatic traction assistance system based on a steering angle of a vehicle, in accordance with an exemplary fifth embodiment of the present invention;
[0051] FIG. 21 illustrates details of a critical steering angle valve and a horizontal linkage assembly attached with a steering mechanism of a heavy duty multi-axle vehicle, in accordance with an exemplary fifth embodiment of the present invention;
[0052] FIG. 22 illustrates operation details of the critical steering angle valve when a first drop arm is oscillated in the fore and apt direction, in accordance with the fifth embodiment of the present invention;
[0053] FIG. 23 illustrates a schematic view of a five-axles vehicle (10x2 configuration) having a non-steer pusher lift axle with a single tire at wheel ends, in accordance with all the exemplary embodiments of the present invention; and

[0054] FIG. 24, which illustrates a schematic view of a multi-axle coach having three axies (6x2 configuration) and a steer or non-steer pusher lift axle with a single tire at wheel ends, in accordance with all the exemplary embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The present invention provides an automatic traction assistance system associated with a lift axle (pusher lift axle) of a heavy commercial multi-axle vehicle having configuration 10x2 and 10x4 with twin steer axles, where the lift axle, i.e. pusher lift axle, is arranged with a pair of ride air springs and a pair of lift air springs. It can be used for multi-axle couch and tractor trailer has either pusher or tag non-steer air suspension. The heavy commercial multi-axle vehicles are hereafter referred as vehicle only for the purpose of explanation, but not by the way of any limitations. The automatic traction assistance system of the present invention is controlled by a steering mechanism of the vehicle. It is especially a valve mechanism attached with the steering system of the vehicle. In addition, it is electrically connected with a lift axle control system used in the multi-axle commercial vehicle. The design of lift axle (1) and the automatic lift axle control system are not a part of the present invention, where these details are known in the art and therefore not described hereafter in detail. Similar reference numerals for same components or parts are being marked and referred in all the embodiments of the present invention as well as from prior art illustrations only for the purpose of easy understanding of the invention, but it is not by the way of any limitations.
[0056] More specially, the automatic traction assistance system of the present invention is attached to the existing multi-axle commercial vehicle and is controlled by the steering mechanism of the vehicle, which controls air pressure of the ride air springs of the air suspension or lift axie based on steering angle. In particular, this automatic traction assistance or control system works based on the movement of a steering mechanism or system of the vehicle or rotation of a steering wheel at a critical steering angle of the vehicle. The critical steering angle of the vehicle is desired and preset within a maximum steering angle of a vehicle wheel at its steered direction (left or right direction). Especially, it controls air pressure in ride air springs of the lift axle based on the critical steering angle of the vehicle, such that when the vehicle

experiences the critical steering angle, the ride air springs of the lift axle are fully deflated or partially deflated to lift-off the lift axle along with the tires from the road surface. Thus, the automatic traction assistance system is automatically and pneumatically operated by the steering mechanism without any necessity of manual operations, which increases maneuverability and traction in the drive axle when the vehicle experiences a sever turn, and thus it enhances life of tire by reducing shoulder scrub in the rear tires of the vehicle, i.e. reducing shoulder scrub of tire for the heavy duty multi-axle vehicle having a pusher lift axle and tandem rear spring suspension.
[0057] Referring to FIG. 4, a schematic view of an automatic traction assistance system (14) based on a steering angle of a vehicle is illustrated, in accordance with an exemplary first embodiment of the present invention. The automatic traction assistance system (14) is operated by the steering mechanism (48) based on the steering angle of the vehicle, where the vehicle is a commercial mufti-axle vehicle having twin steer axles and a lift axle or pusher lift axle (1) that is arranged with the pair of ride air springs (10) and the pair of lift air springs (11). This automatic traction assistance or control system works based on the movement of the steering system of the vehicle. Especially, it controls the air pressure of the ride air springs (10) of the non-steer lift axle according to a critical steering angle (49) of the vehicle. When the vehicle experiences the critical steering angle (49), the ride air springs (10) of the lift axle (1) are fully deflated to lift-off the lift axle (1) with its tires from the road surface.
[0058] The automatic traction assistance system (14), in accordance with an exemplary first embodiment of the present invention, consists of a leveling valve (21), a pilot operated first direction control valve (DCV1, 22), an electrical operated second direction control valve (DCV2, 23), a swinging bracket assembly (63), a pair of linkages assemblies (namely, valve linkage assembly (), steering linkage assembly (64)), a traction assistance electrical switch (TS, 18), a C clamp or bracket assembly (28) and an automatic lift axle control system (15), where the automatic lift axle control system (15) is apart of existing art.
[0059] The automatic traction assistance system (14) is fluidly (pneumatically) connected with the lift axle control system (15) of the vehicle having mechanical suspension. While connecting

the automatic traction assistance system (11) to the lift axle control system (15), a first outlet port (20) of the lift axle control valve (LACV, 16) is fluidly connected with an exhaust port (29) of the pneumatically pilot operated first direction control valve (DCVI, 22) through a line (30). An outlet port (31) of the first direction control valve (DCV1, 22) is fluidly connected to the ride air springs (10) of the lift axle (1) through a quick release valve (QRV, 27) via a line (36), where the quick release valve (QRV1, 27) is connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle (1). An inlet port (33) and the outlet port (31) of the first direction control valve (DCV1, 22) are opened until the signal received from a pilot port (signal port) (32) of the first direction control valve (DCV1, 22), where a silencer is fitted in the inlet port (33) of the DCV1 (22). The first direction control valve (DCV1, 22) is pneumatically operated by the second direction control valve (DCV2, 23) to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn.
[0060] Further, an inlet port (37) of the electrical operated second direction control valve (DCV2, 23) is fluidly connected with a primary air tank (34) through a fluid line (41) and an outlet port (38) of the DCV2 (23) is connected to the pilot port (i.e. signal port, 32) of the DCV1 (22) through a fluid line (pilot line, 42a). An exhaust port (i.e. another outlet port) (39) of the second direction control valve (DCV2, 23) is fluidly connected with an outlet port (42) of the leveling valve (LV, 21) through a fluid line (44). An inlet port (43) of the leveling valve (LV, 21) is fluidly connected to the primary air tank (34) through a fluid line (45). The solenoid of the second direction control valve (DCV, 23) is electrically connected and operated by the traction assistance switch (TS, 18) to provide a pneumatic signal to the first DCV1 (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1), where the traction switch (18) is electrically connected with an ignition switch (IG, 17) of the vehicle through a wire (46). The leveling valve (LV, 21)) is secured to a vehicle frame (4) and pivotally connected to a tie or track rod link (47) of the steering mechanism (48) of the vehicle for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or to supply compressed air to the ride air springs (10) from the primary air tank (34). The leveling valve (21) has a lever (61) that is pivotally connected to the tie rod link (47) through a linkage mechanism (52) secured on a swinging bracket assembly (63), where the tie rod link (47) is connected

between first and second drop arms of the steering mechanism (48). In particular, the leveling valve (21) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (61) of the leveling valve (21) is connected to one end of the swinging bracket assembly (63) through a valve linkage assembly (62), where other end of the swinging bracket assembly is pivotally connected with the valve bracket (60).
[0061] In the normal operation (i.e., the DCV2 (23) is deactivated), the compressed air is passed from the primary air tank (34) to the pilot line (42a) of the DCV1 (22) through the inlet port (37) and the outlet port (38) of the DCV2 (23). The comprised air is supplied to the ride air springs (10) at a required pressure from the LACV (16) through the fluid line (30) and the fluid line (36). When the solenoid of the DCV2 (23) is activated by switch-on the TS (12), the exhaust port (39) of the DCV2 (23) is opened to the outlet port (38) of the DCV2 (23), i.e. the exhaust port (39) of the DCV2 (23) is connected to the primary air tank (34) through the LV (21). The compressed air is passed to the pilot fluid line (42a) of the DCV1 (22) through the LV (21) if the steering wheel (35) is within the critical steering angle (49). The compressed air is supplied to the ride air springs (10) by the DCV1 (22) through the fluid line (36). When the critical steering angle (49) is occurred in the vehicle (detail is provided in the proceeding paragraphs), the LV (21) stops (i.e. cuts-off) the air supply to the fluid line (44) of the DCV2 (23). The air in the pilot fluid line (42a) of the DCV2 (23) and the fluid line (44) is exhausted through the silencer provided in the LV (21); therefore, the exhaust port (29) to the outlet port (31) of the DCV1 (22) is closed, and the inlet port (33) and the outlet port (31) of the DCV1 (22) are opened. Therefore, the ride air springs (10) are fully deflated through the QRV (27) and the inlet port (33) of the DCV1 (22) where the silencer is attached. Therefore, the reaction load in the lift axle is reduced and thus the traction in the drive axle (3a) is increased. When switch-off the TS (12), the inlet port (37) of the DCV2 (23) is opened to the outlet port (38). Therefore, the exhaust port (29, where the first outlet port (20) is connected through the fluid line (30)) of the DCV1 (22) is opened to the outlet port (31) of the DCV1 (22). Thereby, the compressed air is supplied to the ride air springs (10) through the DCV1 (22) through the fluid line (36), i.e. the compressed air is flow from the fluid line (30) to the fluid line (36).

[0062] Referring to FIG. 5, a schematic view of an automatic traction assistance system (14a) based on steering angle of the vehicle is illustrated, in accordance with an exemplary second embodiment of the present invention. The automatic traction assistance system (14a) is operated by the steering mechanism (48) based on the steering angle of the vehicle, where the vehicle is a commercial multi-axle vehicle having twin steer axles and a lift axle or pusher lift axle (1) that is arranged with the pair of ride air springs (10) and the pair of lift air springs (11). This automatic traction assistance or control system (14) works based on the movement of the steering mechanism or system (48) of the vehicle. Especially, it controls the air pressure of the ride air springs (10) of the lift axle based on the critical steering angle (49) of the vehicle. When the vehicle experiences the critical steering angle (49), the ride air springs (10) of the lift axle are fully or partially deflated by maintaining a pre-determined pressure in the ride air springs (10). Similar reference numerals for same components or parts are being marked and referred in all the embodiments of the present invention as well as from prior art illustrations only for the purpose of easy understanding of the invention, but it is not by the way of any limitations.
[0063] The automatic traction assistance system (14a), in accordance with an exemplary second embodiment of the present invention, consists of a leveling valve (21), a pilot operated first direction control valve (DCV1, 22), an electrical operated second direction control valve (DCV2, 23), a pressure limiting valve (PLV, 51), a first quick release valve (QRV1, 27), a second quick release vaive (QRV2, 50), a swinging bracket assembly (63), a linkage mechanism (52), a steering linkage assembly (64), a traction assistance electrical switch (TS, 18), a C clamp or bracket assembly (28) and an automatic lift axle control system (15), where the automatic lift axle control system (15) is a part of existing art. In particular, the automatic traction assistance system (14a), in accordance with an exemplary second embodiment of the present invention, is similar to the first embodiment of the present invention except the addition of second quick release valve (QRV2, 50) and pressure limiting valve (PLV, 51). Additionally, the pressure limiting valve (PLV, 51) and the second quick release valve (QRV2, 50) are fluidly connected to the inlet port (33) of the DCV1 (22) of the first embodiment of the present invention. The pressure limiting valve (51) is fluidly connected between the primary air tank (34) and an inlet port (33) of the first DCV1 (22) through the second QRV2 (50). The first quick release valve (QRV1, 27) is connected to the ride air springs (10) to rapidly exhaust the air from the ride air

springs (10), which deflates the ride air springs (10) to lift the lift axle (1), whereas the second quick release valve (QRV2, 50) is connected between the pressure limiting valve (51) and the first DCV1 (22) to exhaust air from an exhaust line (65) extended from the first DCV1 (22). The PLV (51) actuates the second quick release valve (QRV2, 50) to limit the air pressure to the ride air springs (10) for partial deflation of the ride air springs (10) when the vehicle reaches the critical steering angle (49) during sever turn. Other arrangements and components of the second embodiment of the present invention are same as the first embodiment of the present invention. The automatic traction assistance system (14), in accordance with an exemplary second embodiment of the present invention, is fluid connected with the lift axle control system (15) of the vehicle having mechanical suspension.
[0064] The operation principle of the second embodiment of the present invention is similar to the first embodiment of the present invention except when the vehicle experiences the critical steering angle (49). When the critical steering angle (49) is occurred in the vehicle (detail is provided in the proceeding paragraphs), the LV (21) stops (i.e. cuts-off) the compressed air supply to the DCV2 (23). The compressed air in the pilot line (42a) of the DCV2 (23) is exhausted through the silencer of the LV (21), and therefore, the ride air springs (23) are partially deflated through the QRV1 (27) up to the pressure preset at the PLV (51) as the compressed air is passed from the primary air tank (34) to the ride air springs (23) through the PLV (51), the QRV2 (50), the DCV1 (22), and the QRV1 (27). Thus, the ride air springs (10) are partially deflated instead of fully deflation, and thereby the reaction load in the axle is reduced to a desired magnitude, which increases the traction in the drive axle (3a).
[0065] FIGS. 6(a) and 6(b) illustrate a schematic view of a leveling valve (LV, 21) and a linkage mechanism (52) attached with a steering mechanism (48) of the heavy duty multi-axle vehicle, in accordance with the present invention. The steering mechanism (48) consists of a pair of drop arms (54a, 54b), i.e. first drop arm (54a) and second drop arm (54b), a tie rod link (47), a pair of drag links, i.e. first drag link (55a) and second drag link(55b), a pair of steering levers, i.e. first steering lever (56a) and second steering lever(56b), a steering wheel (35), a steering stem (57) with a pair of universal joints, a hydraulic steering pump (58) and a hydraulic booster cylinder (59). When the steering wheel (35) is turned manually by the operator during turn, the steering

stem (57) is rotated, such that the drop arms (54a, 54b) are oscillated with respective to their pivot joints at a same angle with the tie rod link (47). The steering mechanism (48) controls the movement of wheels of both the first front axle (2a) and second front axle (2b). The first drag link (55a) and the second drag link (55b) are moved relatively to each others, and therefore the wheels of the second front axle (2a) turn relatively to the wheels of first front axle (2a). The LV (21) is secured to the vehicle frame (4) and is pivotally attached to the tie rod link (47) of the steering mechanism (48) through a linkage mechanism (52) (detail is provided in the proceeding paragraphs), in accordance with an exemplary first embodiment of the present invention. The tie rod link (47) is connected between first and second drop arms (54a, 54b) of the steering mechanism (48).
[0066] FIGS. 7(a) and 7(b) illustrate details of critical steering angle (49) and maximum steering angle (max. cut angle) of tire of the commercial multi-axle vehicle at left-hand (LH) turn and right-hand (RH) turn, respectively, in accordance with all exemplary embodiments of the present invention. The steering angle of the vehicle is defined as an angle between the front of the vehicle and the steered wheel direction as shown in FIG. 7(b). When the vehicle having configuration of 10x2 or 10x4 with the lift axle (1) is experienced the sever turn, the tires (wheels) of the front axles (2a, 2b) are steered and the tires of the lift axle (1) and the tag axle (3b) are subjected to a sever scrub. The critical steering angle (49) of the tire is a steering angle, in which the tires of the lift axle (1) and the tag axle (3b) are started to subject to the sever scrub. In particular, the critical steer angle (49) is an angle at which the shoulder scrub starts in the tires when the vehicle is experiences a hard turns in both the RH and LFI turn, where the critical steer angle (49) of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction, i.e. left or right direction of steering of the front axle by the steering mechanism when the vehicle experiences sever turn.
[0067] FIG. 8 illustrates details of the automatic traction assistance system (14) fitted in the vehicle frame (4) and the steering linkages (48) of the vehicle having twin front axle, in accordance with the first and second embodiments of the present invention. The leveling valve (LA, 21) is secured to a valve bracket (60) that is attached to the frame (4) of the vehicle. The lever (61) of the leveling valve (21) is connected pivotally with the one end of linkage

mechanism (52) using a spherical joint (i.e., ball joint), whereas the other end of linkage mechanism (52) is connected to the swinging bracket assembly (63) and the steering linkage assembly (64, horizontal linkage) using spherical joints. The swinging bracket assembly (63) is pivotaily connected with the valve bracket (60) and is also connected with the valve linkage assembly (62, vertical linkage assembly) using ball joints. The other end of the steering linkage assembly (64) is connected to the tie rod link (47) of the steering mechanism (48) of the vehicle through the C clamp assembly (28). The leveling valve (21) is pneumatically connected in between the primary air tank (34) and the second DCV2 (23) such that the leveling valve (21) controls the operation of the first DCV1 (22) in order to deflate the ride air springs (10) or to supply compressed air to the ride air springs (10) through the second DCV2 (23).
[0068] When the vehicle is in laden condition, the solenoid of the DCV2 (23) is activated by the traction switch (TS, 18), which is usually operated by vehicle operator (driver). When the vehicle is operated in a straight ahead or experienced less than the critical steering angle (i.e. desired pre¬determined steering angle, 49), the pilot line (42a) of the first direction control valve (DCV1, 22) is fluidly connected to the primary air tank (34) through the fluid lines (41, 44, 45). At this time, the leveling valve (LA, 21) supplies the compressed air from the primary air tank (34) to the pilot line (42a) of the first DCV1 (22), where the lever (61) of the leveling valve (21) is in a negative (-) angle, such that the compressed air is passed from the LACV (16) to the ride air springs (10).
[0069] Similarly, when the vehicle experiences the sever turn, the steering angle of the vehicle is increased beyond the critical steering angle (49) (i.e. pre-set steering angle). The lever (61) of the leveling valve (21) is moved to upward and reached to a positive angle (+) direction with respect to the movement of tie rod link (47) actuated by the steering mechanism (48) such that the compressed air in the pilot line (42a) of the first DCV1 (22) is exhausted through the silencer of the LV (21). In In accordance with the exemplary first embodiment of the present invention, the compressed air in the ride air springs (10) is fully exhausted immediately. Thus, the reaction on the lift axle (1) is reduced to the self-weight of the axle. Thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire shoulder scrub even when the vehicle experiences the sever turn.

[0070] In accordance with the exemplary second embodiment of the present invention, the automatic traction assistance control system maintains a pre-determined air pressure in the ride air springs instead of full deflation. That is, the compressed air is exhausted from the ride air springs until to reach equal pressure of the pre-determined air pressure. The air pressure is usually lower than the magnitude of air pressure maintained in the ride air springs (10) at normal laden operation. In order to maintain the pre-determined air pressure, the pressure limiting valve (51) and the quick release valve (50) are connected in the inlet port (33) of the first DCV1 (22) through a fluid line (65). Therefore, when the vehicle is operated a straight ahead (i.e., experiences less than the critical steering angle (49), the automatic traction assistance control system works as same as the first embodiment of the present invention, whereas when the vehicle experiences the sever turn (i.e. the vehicle steering angle is increased beyond the critical steering angle (49)), the compressed air in the pilot line (42a) of the first DCVI (22) is exhausted. The outlet of the PLV (51) is fluidly connected to the ride air springs (10) of the lift axle (1) through the second quick release valve QRV2 (50) in the fluid line (65). Thereby, the pre-determined pressure set at the pressure limiting valve (51) is maintained in the ride air springs (10), which reduces the reaction on the lift axle (1). Thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire shoulder scrub even when the vehicle experiences the sever turn.
[0071] In accordance with the above discussed first and second embodiments of the present invention, the input signal (i.e. control) is taken from the tie rod link (47) connected in between the first and second drop arms (54a, 54b) of the steering mechanism (48) of the vehicle. As shown in Figure 8, the leveling valve (21), the linkage assembly (52) and the steering linkage assembly (64) are attached to the tie rod link (47) of the vehicle. The leveling valve (21) is secured with the vehicle frame (4) near the first front axle (2a) of the vehicle and is pivotally attached to the tie rod link (47) of the vehicle through the linkage mechanism (52) and the steering linkage assembly (64). When the vehicle experiences the turn, the first drop arm (54a) and the second drop arm (54b) are oscillated to increase the angle of drop arms, such that the tie rod link (47) is moved either forward or backward direction, which in turns oscillates the lever (61) of the leveling valve (21) through the linkage mechanism (52) and the steering linkage assembly (64).

[0072] FIG. 9 illustrates operation details of the leveling valve (21), the linkage mechanism (52) and the steering linkage assembly (64), in accordance with the first and second embodiments of the present invention. The leveling valve (21), the linkage mechanism (52) and the steering linkage assembly (64) are operated when the tie rod link (drag links) (47) is moved in the fore and apt direction. When the vehicle experiences the positive steer angle (Right-Hand turn of vehicle) beyond the critical steering angle (49), the lever (61) of the leveling valve (21) is moved upward. When the vehicle experiences the negative steer angle (Left-Hand turn of vehicle) beyond the critical steering angle (49), the lever (61) of the leveling valve (21) is moved upward. Therefore, the movement of the lever (61) of the leveling valve (21) controls the operation of the first DCV1 (22) and the second DCV2 (23) for controlling the air pressure of the ride air springs (10) of the lift axle (1), which fully deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn according to the first embodiment of the present invention. Similarly, in accordance with the second embodiment of the present invention, the movement of the lever (61) of the leveling valve (21) controls the operation of the first DCV1 (22) and the second DCV2 (23) for controlling the air pressure of the ride air springs (10) of the lift axle (1), which fully or partially deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn, i.e. the partial deflation of the ride air springs (10) are maintained at a pre-determined pressure by the pressure limiting valve (51).
[0073] FIG. 10 illustrates an exploded view of the leveling valve (21), the linkage mechanism (52) and the steering linkage assembly (64), in accordance with the first and second embodiments of the present invention. The leveling valve (21) is secured to the valve bracket (60) such that the lever (61) of the leveling valve (21) is pivotally attached to the vertical linkage assembly (62) of the linkage mechanism (52). The bottom portion of the vertical linkage assembly (62) is pivotally mounted with the swinging bracket assembly (63), which is pivotally attached to the valve bracket (60). The steering linkage assembly (i.e. horizontal linkage assembly, 64), having ball joint at both the ends, is pivotally attached to the swinging bracket assembly (63) at the middle portion. The other end of the steering linkage assembly (64) is

pivotally mounted with the C clamp assembly (28), where the C Clamp assembly (28) is secured to the tie rod link (47) of the steering mechanism (48) of the vehicle.
[0074] FIG. II illustrates an exploded view of the swinging bracket assembly (63), in accordance with the first, second and third embodiments of the present invention. The swinging bracket assembly (63) is specially designed in order to prevent a shaking during the movement of steering linkage. The swinging bracket assembly (63) consists of a pair of ball bearings (66), a circlip (67), a inner spacer ring (68), a spindle (69), a bearing housing bracket (70) and a lock nut (73). The bearing housing bracket (70) is made of a Z plate (71) welded with a cylindrical housing (72), The ball bearings (66) are inserted into the cylindrical housing (70) and holed using the circlip (67). The spindle (69) holds the bearing housing (70) along with the bearings (66) and secured with the valve bracket (60) using the nut (73). Such .constructional arrangements of the swinging bracket assembly (63) can prevent the shaking during the movement of steering linkage.
[0075] FIG. 12 illustrates a detailed view of the valve bracket (60), in accordance with the present invention. The valve bracke (60) consists of a Z plate (74) and a L shaped bracket (75). A boss (76), having a cylindrical shape, is welded with the L shaped bracket (75), where the L shaped bracket (75) is welded to the Z plate (74). The valve bracket (60) has multiple holes (77) that are used to secure the leveling valve (21) with the valve bracket (60). In addition, the valve bracket (60) has a pair of holes (78), which are used to attach the valve bracket (60) to the frame (4) of the vehicle.
[0076] FIG. 13 illustrates a detailed view of the C clamp or bracket assembly (28), in accordance with the present invention. The C clamp or bracket assembly (28) consists of a first C bracket (79) and second C bracket (80). The first C bracket (79) is C shaped plate with multiple holes, whereas the second C bracket (80) is also C shaped plate with multiple holes. Further, the first C bracket (79) has an extended portion with a hole provided at its edge, where the hole at the extended portion is used to attach with the ball bearing (66) of the linkage mechanism (52). The multiple holes are used to clamp the first C bracket (79) and the second C bracket (80) along with the tie rod link (47) being placed within the first and second C brackets (79, 80).

[0077] In the above discussed first and second embodiments of the present invention, the leveling valve (21) decides the compressed air in the pilot line (42a) of the DCV1 (22) such that the ride air springs (10) are either fully deflated or partially deflated. The lever (61) of the leveling valve (21) is connected to the tie rod link (47) of the steering mechanism (48), such that the tie rod link (47) oscillates the lever (61) of the leveling valve (21) with respect to the movement of steering mechanism (48). When the vehicle reaches the desired or critical steering angle (49) during sever turn, the leveling valve (21) controls the operation of first and second direction control valves (22, 23), which controls air pressure in the ride air springs (6) in order to fully or partially deflate the ride air springs (6) based on the steering angle of the vehicle.
[0078] FIG. 14(a) and 14(b) illustrate a schematic view of an automatic traction assistance system (14b) based on steering angle of the vehicle, in accordance with an exemplary third embodiment of the present invention. The automatic traction assistance system (14b) is operated by the steering mechanism (48) based on the steering angle of the vehicle, where the vehicle is a commercial multi-axle vehicle having twin steer axles and a lift axle or pusher lift axle (1) that is arranged with the pair of ride air springs (10) and the pair of lift air springs (11). This automatic traction assistance or control system (14) works based on the movement of the steering mechanism or system (48) of the vehicle. Especially, it controls the air pressure of the ride air springs (10) of the lift axle based on the critical steering angle (49) of the vehicle. When the vehicle experiences the critical steering angle (49), the ride air springs (10) of the lift axle are fully or partially deflated by maintaining a pre-determined pressure in the ride air springs (10). Similar reference numerals for same components or parts are being marked and referred in all the embodiments of the present invention as well as from prior art illustrations only for the purpose of easy understanding of the invention, but it is not by the way of any limitations.
[0079] The automatic traction assistance system (14b), in accordance with an exemplary third embodiment of the present invention, consists of a leveling valve (21), a pilot operated first direction control valve (DCV1, 22), an electrical operated second direction control valve (DCV2, 23), a pressure limiting valve (PLV, 51), a first quick release valve (QRV3, 27), a second quick release valve (QRV2, 50), a swinging bracket assembly (63), a linkage mechanism (52), a

steering linkage assembly (64), a traction assistance electrical switch (TS, 18), a C clamp or bracket assembly (28) and an automatic lift axle control system (15), where the automatic lift axle control system (15) is a part of existing art. In particular, the automatic traction assistance system (14b), in accordance with an exemplary third embodiment of the present invention, is similar to the second embodiment of the present invention except that the limiting valve (LV, 21) is pivotally attached to either the first drop arm (54a) of the steering mechanism (as shown in FIG. 14a) or the second drop arm (54b) of the steering mechanism (48) (as shown in FIG. 14b) instead of the tie rod link (47). Other arrangements and components of the third embodiment of the present invention are same as the second embodiment of the present invention. When the vehicle experiences the sever turn, the drop arms (54a, 54b) are oscillated to move fore and apt direction, which results in movement of the steering linkage assembly (i.e. horizontal linkage assembly, 64) that is secured with one of the drop arms (54a, 54b). Therefore, the lever (61) of the leveling valve (LA, 21) is also oscillated such that the leveling valve (LA, 21) decides the air in the pilot line (42a) of the first DCV1 (22) according to the angle of drop arms (54a, 54b). Thus, the ride air springs (10) are fully deflated or partially deflated according to the steering angle of the vehicle.
[0080] FIG. 15 illustrates details of the leveling valve (21) and the linkage mechanism (52) attached with the first drop arm (54a) of the steering mechanism (48), in accordance with an exemplary third embodiment of the present invention. The leveling valve (21) and the linkage mechanism (52) are attached with the first drop arm (54a) of the steering mechanism (48) of the heavy duty multi-axle vehicles, MAV having twin front steer axles. The horizontal linkage assembly (64) is pivotally attached with the swinging bracket (63) and is pivotally attached to the first drop arm (54a) of the vehicle.
[0081] FIG. 16 illustrates operation details of the leveling valve (21), the linkage mechanism (52) and the steering linkage assembly (64) when the first drop arm (54a) is oscillated, in accordance with the third embodiment of the present invention. The leveling valve (21), the linkage mechanism (52) and the steering linkage assiembly (64) are operated and moved when one of the drop arms (54a, 54b) is oscillated in the fore and apt direction. When the vehicle experiences the positive steer angle (RH turn of vehicle) beyond the critical steering angle (49),

the lever (61) of the leveling valve (21) is moved in upward direction. When the vehicle experiences the negative steer angle (Left-Hand turn of vehicle) beyond the critical steering angle (49), the lever (61) of the leveling valve (21) is moved upward. Therefore, the movement of the lever (61) of the leveling valve (21) controls the operation of the first DCV1 (22) and the second DCV2 (23) for controlling the air pressure of the ride air springs (10) of the lift axle (1), which fully deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn according to the first embodiment of the present invention. Similarly, in accordance with the second embodiment of the present invention, the movement of the lever (61) of the leveling valve (21) controls the operation of the first DCV1 (22) and the second DCV2 (23) for controlling the air pressure of the ride air springs (10) of the lift axle (3), which fully or partially deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn, i.e. the partial deflation of the ride air springs (10) are maintained at a pre-determined pressure by the pressure limiting valve (51).
[0082] FIG. 17(a) illustrates a schematic view of an automatic traction assistance system (14c) based on steering angle of the vehicle, in accordance with an exemplary fourth embodiment of the present invention. The automatic traction assistance system (14c) is operated by the steering mechanism (48) based on the steering angle of the vehicle, where the vehicle is a commercial multi-axle vehicle having twin steer axles and a lift axle or pusher lift axle (1) that is arranged with the pair of ride air springs (10) and the pair of lift air springs (11). This automatic traction assistance or control system (14) works based on the movement of the steering mechanism or system (48) of the vehicle. Especially, it controls the air pressure of the ride air springs (10) of the lift axle based on the critical steering angle (49) of the vehicle. When the vehicle experiences the critical steering angle (49), the ride air springs (10) of the lift axle are fully or partially deflated by maintaining a pre-determined pressure in the ride air springs (10). Similar reference numerals for same components or parts are being marked and referred in all the embodiments of the present invention as well as from prior art illustrations only for the purpose of easy understanding of the invention, but it is not by the way of any limitations.
[0083] The automatic traction assistance system (14c), in accordance with an exemplary fourth embodiment of the present invention, consists of a critical steering angle valve (80), a horizontal

linkage assembly (82), a pilot operated first direction control valve (DCV1, 22), an electrical operated second direction control valve (DCV2, 23), a pressure limiting valve (PLV, 51), a first quick release valve (QRV1, 27), a second quick release valve (QRV2, 50), a traction assistance electrical switch (TS, 18), a C clamp or bracket assembly (28) and an automatic lift axle control system (15), where the automatic lift axle control system (15) is a part of existing art. In particular, the automatic traction assistance system (14c), in accordance with an exemplary fourth embodiment of the present invention, is similar to the second embodiment of the present invention except that the critical steering angle valve (80) replaces the leveling valve (21) used in the first and second embodiments of the present invention. In addition, as the critical steering angle valve (80) is especially designed for the specific application, the swinging bracket assembly (63) used in the first embodiment and second embodiment is not required in this fourth embodiment. Further, the design of the critical steering angle valve is not the part of this present invention, and thus it is not described in detail.
[0084] The critical steering angle valve (80) and the horizontal linkage assembly (82) are attached with the steering mechanism (48) of the heavy duty multi-axle vehicles, MAV having twin front steer axles, in accordance with an exemplary fourth embodiment of the present invention. The critical steering angle valve (80) is pivotally attached to the tie rod link (47) of the steering mechanism (as shown in FIG. 17a). Other arrangements and components of the fourth embodiment of the present invention are same as the second embodiment of the present invention. The lever (81) of the critical steering angle valve (80) is pivotally connected to the C clamp or bracket assembly (28) through a horizontal linkage assembly (82) which has spherical ball joints at both ends (as shown in FIG. 17a. Further, the critical steering angle valve (80) is composed of an inlet port (84) and an outlet port (85), where the inlet port (84) of the critical steering angle valve (80) is pneumatically connected to the primary air tank (34) through the fluid lines (41, 45) and the outlet port (85) of the critical steering angle valve (80) is pneumatically connected to the exhaust or another outlet port (39) of the second DCV2 (23) through the fluid line (44). The critical steering angle valve (80) is fluidly connected in between the primary air tank (34) and the second DCV2 (23) such that the critical steering angle valve (80) controls the operation of the first DCV1 (22) to fully or partially deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23).

[0085] FIG. 17b illustrates working principle of the critical steering angle valve (80) with respect to lever angle (movement), in accordance with the exemplary fourth embodiment of the present invention. When the vehicle is operated or experiences the sever turn, the tie rod link (47) of the steering mechanism (48) is moved either the fore or apt direction, which results in movement of the horizontal linkage assembly (82) that is pivotally attached to the tie rod link (47). The lever (81) of the critical steering angle valve (80) is oscillated such that the critical steering angle valve (80) decides the air in the pilot line (42a) of the first DCV1 (22) according to the movement of the tie rod link (47) with respect to the movement of steering wheel of the steering mechanism (48). When the vehicle experiences a right hand side turn (RH Turn), the lever (81) of the critical steering angle valve (80) moves to RH turn side and shows a positive angle (+'ve), whereas when the vehicle experiences a left hand side turn (LH Turn), the lever (81) of the critical steering angle valve (80) moves to LH turn side and shows a negative angle (-*ve). When the angle of lever (81) is within the critical steering angle (49), the critical steering angle valve (80) allows the air from the inlet port (84) to the outlet port (85). When the vehicle experiences the sever turn in RH side, the lever (81) of the critical steering angle valve (80) reaches the critical steering angle (49) in RH side, such that the inlet port (84) of the critical steering angle valve (80) is closed to the outlet port (85), which stops the compressed air supply to the outlet port (85) immediately. Similarly, when the vehicle experiences the sever turn in LH side, the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49) in LH side, such that the inlet port (84) of the critical steer angle valve (80) is closed to outlet port (85), which stops the compressed air supply to the outlet port (85) immediately.
[0086] FIG. 38 illustrates details of the critical steering angle valve (80) and the linkage mechanism (82) attached with the steering mechanism (48) of the heavy duty multi-axle vehicle, in accordance with an exemplary fourth embodiment of the present invention. The horizontal linkage assembly (82) is pivotally attached with the lever (81) of the critical steering angle valve (80) and the tie rod link (47) of the steering mechanism (48) of the vehicle. The critical steering angle valve (80) is mounted to a valve bracket (60) through which the critical steering angle valve (80) is attached to the frame (4) of the vehicle. The lever (81) of the critical steering angle valve (80) is pivotally connected with the one end of horizontal linkage assembly (82) using a

spherical joint (i.e. ball joint), whereas other end of the horizontal linkage assembly (82) is connected to the C clamp or bracket assembly (28) using spherical joints. The C clamp or bracket assembly (28) is secured with the tie rod link (47) of the steering mechanism (48) as like the arrangement discussed in the first and second embodiments of the present invention. The critical steering angle valve (80) is pneumatically connected to the DCV1 (22) through the DCV2 (23) and the primary air tank (34) as similar as the leveling valve (21) connected (used) in the first and second embodiments of the present invention. Therefore, the critical steering angle valve (80) replaces the leveling valve (21) of the first and second embodiments of the present invention.
[0087] FIG. 19 illustrates operation details of the critical steering angle valve (80) when the tie rod link (47) is moved in the fore and apt direction, in accordance with the fourth embodiment of the present invention. If the vehicle experiences the positive steer angle (in RH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which fully deflates the ride air springs (10) if the fourth embodiment of the present invention (i.e. critical steering angle valve is pivotally attached with the tie rod link) replaces the leveling valve (21) of the first embodiment of the present invention. Whereas, if the vehicle experiences the positive steer angle (in RH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which either partially or fully deflates the ride air springs (10) if the fourth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with the tie rod link (47)) replaces the leveling valve (21) of the second embodiment of the present invention.
[0088] Similarly, when the vehicle experiences the negative steer angle (in LH turn of vehicle) beyond the critical steering tingle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which fully deflates the ride air springs (10) if the fourth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with the tie rod link (47)) replaces the leveling valve (21) of the first embodiment of present invention. Whereas, if the vehicle experiences the negative steer angle (in LH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80)

reaches the critical steer angle (49), which either partially or fully deflates the ride air springs (10) if the fourth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with the tie rod link (47)) replaces the leveling valve (21) of the second embodiment of the present invention.
[0089] When the fourth embodiment of the present invention (i.e. critical steering angle valve (80)) replaces the leveling valve (21) of the first embodiment of present invention and the vehicle experiences a straight ahead or less than the critical steering angle (49), the pilot line (42a) of the first direction control valve (22) is fluidly connected to the primary air tank (34) through the fluid lines (42a, 44, 45). At this time, the critical steering angle valve (80) supplies the compressed air from the air tank (34) to the pilot line (42a) of the first DCV1 (22). The lever (81) of the critical steering angle valve (80) is oscillated within the critical steering angle (49), so that the compressed air is passed from the LACV (16) to the ride air springs (10). When the vehicle experiences the sever turn, the steering angle of the vehicle is increased beyond the critical steering angle (49) and the lever (81) of the critical steering angle valve (80) is moved beyond the critical steering angle (49) either at the positive angle (+'ve) direction or the negative angle (-'ve) direction, so that the air in the pilot line (44) of the second DCV2 (23) is exhausted through the silencer of the critical steering angle valve (80). As soon as, the air in the ride air springs (10) is fully exhausted immediately, which ensures that the reaction on the lift axle (1) is reduced to the self-weight of the axle. Thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire scrub even when the vehicle experiences the sever turn.
[0090] When the fourth embodiment of the present invention (i.e. critical steering angle valve (80)) replaces the leveling valve (21) of the second embodiment of present invention and the vehicle experiences a straight ahead or less than the critical steering angle (49), the pilot line (42a) of the first direction control valve (22) is fluidly connected to the primary air tank (34) through the lines (42a, 44, 45). At this time, the critical steering angle valve (80) supplies the compressed air from the air tank (34) to the pilot line (42a) of the first DCV1 (22). The lever (81) of the critical steering angle valve (80) is oscillated within the critical steering angle (49), so that the compressed air is passed from the LACV (16) to the ride air springs (10). When the vehicle

experiences the sever turn, the steering angle of the vehicle is increased beyond the critical steering angle (49) and the lever (81) of the critical steering valve (80) is moved beyond the critical steering angle (49) at either the positive angle (+'ve) direction or the negative angle (-*ve) direction, so that the air in the pilot lines (42a) of the second DCV2 (23) is exhausted through the silencer of the critical steering angle (49). As soon as, the air in the ride air springs (10) is partially exhausted immediately, i.e. the ride air springs (10) are not fully deflated, where the air pressure in the ride air springs (10) is maintained to the level of air pressure preset at the pressure limiting valve (51). Such partial deflation of the ride air springs (10) reduces the reaction on the lift axle (1), and thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire shoulder scrub even when the vehicle experiences the sever turn.
[0091] FIG. 20(a) and 20(b) illustrate a schematic view of an automatic traction assistance system (14d) based on steering angle of the vehicle, in accordance with an exemplary fifth embodiment of the present invention. The automatic traction assistance system (14d) is operated by the steering mechanism (48) based on the steering angle of the vehicle, where the vehicle is a commercial multi-axle vehicle having twin steer axles and a lift axle or pusher lift axle (1) that is arranged with the pair of ride air springs (10) and the pair of lift air springs (11). This automatic traction assistance or control system (14d) works based on the movement of the steering mechanism or system (48) of the vehicle. Especially, it controls the air pressure of the ride air springs (10) of the lift axle based on the critical steering angle (49) of the vehicle. When the vehicle experiences the critical steering angle (49), the ride air springs (10) of the lift axle are fully or partially deflated by maintaining a pre-determined pressure in the ride air springs (10). Similar reference numerals for same components or parts are being marked and referred in all the embodiments of the present invention as well as from prior art illustrations only for the purpose of easy understanding of the invention, but it is not by the way of any limitations.
[0092] The automatic traction assistance system (14d), in accordance with an exemplary fifth embodiment of the present invention, consists of a critical steering angle valve (80), a horizontal linkage assembly (82), a pilot operated first direction control valve (DCV1, 22), an electrical operated second direction control valve (DCV2, 23), a pressure limiting valve (PLV, 51), a first

quick release valve (QRV1, 27), a second quick release valve (QRV2, 50), a traction assistance electrical switch (TS, 18), a C clamp or bracket assembly (28) and an automatic lift axle control system (15), where the automatic lift axle control system (15) is a part of existing art. In particular, the automatic traction assistance system (14d), in accordance with an exemplary fifth embodiment of the present invention, is similar to the fourth embodiment of the present invention except that the critical steering angle valve (80) is pivotally attached to either the first drop arm (54a) of the steering mechanism (48) (as shown in FIG. 20a) or the second drop arm (54b) of the steering mechanism (48) (as shown in FIG. 20b) instead of the tie rod link (47). Other arrangements and components of the fifth embodiment of the present invention are same as the fourth embodiment of the present invention.
[0093] The critical steering angle valve (80) and the horizontal linkage assembly (82) are attached with the steering mechanism (48) of the heavy duty multi-axle vehicle The lever (81) of the critical steering angle valve (80) is pivotally connected to either the first drop arm (54a) or the second drop arm (54b) through the horizontal linkage assembly (82) which has ball joints at both ends. When the vehicle experiences the sever turn, the drop arms (54a, 54b) are oscillated to move in the fore and apt direction, which results in movement of the horizontal linkage assembly (82) that is secured with one of the drop arms (54a, 54b). Therefore, the lever (81) of the critical steering angle valve (80) is also oscillated such that the critical steering angle valve (80) decides the air in the pilot line (42a) of the first DCV1 (22) according to the angle of drop arms (54a, 54b). Thus, the ride air springs (10) are fully deflated or partially deflated according to the steering angle of the vehicle.
[0094] FIG. 21 illustrates details of the critical steering angle valve (80) and the horizontal linkage assembly (82) attached with the steering mechanism (48) of the heavy duty multi-axle vehicle, in accordance with an exemplary fifth embodiment of the present invention. The horizontal linkage assembly (82) is pivotally attached with the lever (81) of the critical steering angle valve (80) and either the first drop arm (54a) or the second drop arm (54b) of the steering mechanism (48) of the vehicle. The critical steering angle valve (80) is mounted to a valve bracket (60) through which the critical steering angle valve (80) is attached to the frame (4) of the vehicle. The lever (81) of the critical steering angle valve (80) is pivotally connected with

one end of the horizontal linkage assembly or mechanism (82) using a spherical joint (i.e. ball joint), whereas other end of the horizontal linkage assembly (82) is pivotally to either the first drop arm (54a) or the second drop arm (54b) using spherical joints. The critical steering angle valve (80) is pneumatically connected to the DCV1 (22) through the DCV2 (23) and the primary air tank (34) as similar as the leveling valve (21) connected (used) in the first embodiment and second embodiment of the present invention. Therefore, the critical steering angle valve (80) replaces the leveling valve (21) of the first and second embodiments of the present invention.
[0095] FIG. 22 illustrates operation details of the critical steering angle valve (80) when the first drop arm (54a) is oscillated in the fore and apt direction, in accordance with the fifth embodiment of the present invention. If the vehicle experiences the positive steer angle (in RH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which fully deflates the ride air springs (10) if the fifth embodiment of the present invention (i.e. critical steering angle valve is pivotally attached with one of the drop arms) replaces the leveling valve (21) of the first embodiment of the present invention. Whereas, if the vehicle experiences the positive steer angle (in RH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which either partially or fully deflates the ride air springs (10) if the fifth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with one of the drop arms) replaces the leveling valve (21) of the second embodiment of the present invention.
[0096] Similarly, when the vehicle experiences the negative steer angle (in LH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steering angle (49), which fully deflates the ride air springs (10) if the fifth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with one of the drop arms) replaces the leveling valve (21) of the first embodiment of present invention. Whereas, if the vehicle experiences the negative steer angle (in LH turn of vehicle) beyond the critical steering angle (49), the lever (81) of the critical steering angle valve (80) reaches the critical steer angle (49), which either partially or fully deflates the ride air springs (21) if the fifth embodiment of the present invention (i.e. critical steering angle valve (80) is

pivotally attached with one of the drop arms) replaces the leveling valve (21) of the second embodiment of the present invention.
[0097] When the fifth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with one of the drop arms) replaces the leveling valve (21) of the first embodiment of present invention and the vehicle experiences a straight ahead or less than the critical steering angle (49), the pilot line (42a) of the first direction control valve (22) is fluidly connected to the primary air tank (34) through the fluid lines (42a, 44, 45). At this time, the critical steering angle valve (80) supplies the compressed air from the air tank (34) to the pilot line (42a) of the first DCV1 (22). The lever (81) of the critical steering angle valve (80) is oscillated within the critical steering angle (49), so that the compressed air is passed from the LACV (16) to the ride air springs (10). When the vehicle experiences the sever turn, the steering angle of the vehicle is increased beyond the critical steering angle (49) and the lever (81) of the critical steering angle valve (80) is moved beyond the critical steering angle (49) either at the positive angle (+'ve) direction or the negative angle (-'ve) direction, so that the air in the pilot line (42a) of the second DCV2 (23) is exhausted through the silencer of the critical steering angle valve (80). As soon as, the air in the ride air springs (10) is fully exhausted immediately, which ensures that the reaction on the lift axle (1) is reduced to the self-weight of the axle. Thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire scrub even when the vehicle experiences the sever turn.
[0098] When the fifth embodiment of the present invention (i.e. critical steering angle valve (80) is pivotally attached with one of the drop arms) replaces the leveling valve (21) of the second embodiment of the present invention and the vehicle experiences a straight ahead or less than the critical steering angle (49), the pilot line (42a) of the first direction control valve (22) is fluidly connected to the primary air tank (34) through the lines (42a, 44, 45). At this time, the critical steering angle valve (80) supplies the compressed air from the air tank (34) to the pilot line (42a) of the first DCV1 (22). The lever (81) of the critical steering angle valve (80) is oscillated within critical steering angle (49), so that the compressed air is passed from the LACV (16) to the ride air springs (10). When the vehicle experiences the sever turn, the steering angle of the vehicle is increased beyond the critical steering angle (49) and the lever (81) of the critical steering angle

valve (80) is moved beyond the critical steering angle (49) at either the positive angle (+'ve) direction or the negative angle (-*ve) direction, so that the air in the pilot lines (42a) of the second DCV2 (23) is exhausted through the silencer of the critical steering angle valve (80). As soon as, the air in the ride air springs (10) is partially exhausted immediately, i.e. the ride air springs (10) are not fully deflated, where the air pressure in the ride air springs (10) is maintained to the level of air pressure preset at the pressure limiting valve (51). Such partial deflation of the ride air springs (10) reduces the reaction on the lift axle (1), and thereby, the maneuverability and traction of the vehicle is increased, which significantly reduces tire shoulder scrub even when the vehicle experiences the sever turn.
[0099] In addition, the present invention is applicable for all the range of commercial trucks having steer/non-steer pusher or tag air suspension having either single tire or dual tires, as shown in FIG. 23, which illustrates a schematic view of a five-axles vehicle (10x2 configuration) having a non-steer pusher lift axle with a single tire at wheel ends, and multi-axle couch having non-steer pusher or tag air suspension, as shown in FIG. 24, which illustrates a schematic view of a multi-axle coach having three axles (6x2 configuration) and a steer or non-steer pusher lift axle with a single tire at wheel ends.
[00100] The automatic traction assistance or control system of all the embodiments of the present invention increases the traction automatically in the vehicle when the vehicle experiences a sever turn. In the present design of the automatic traction assistance or control system, the ride air springs (10) are either fully or partially deflated when the vehicle experiences the critical steering angle (49), so that the reaction load on the pusher lift axle (1) is reduced significantly until the front steering wheel return to the steering angle less than the critical steering angle (49). The present invention of the automatic traction assistance or control system provides a unique arrangement of the linkage system (52) which is pivotaliy attached to either the first tie rod link (47) or one of the drop arms (54a, 54b) of the steering mechanism (48) of the vehicle. The present invention of the automatic traction assistance or control system uses the simple leveling valve (21) (which can already be validated in the air suspension of trucks and bus) for either fully or partially deflating the ride air springs (10) when the vehicle experiences the critical steering angle (49).The present invention of the automatic traction assistance or control system is

automatically operated by the steering mechanism based on the steering angle of the vehicle during sever turn, i.e. works based on the movement of the steering system of the vehicle. Especially, the automatic traction assistance or control system controls the air pressure of the ride air springs of the non-steer lift axle based on the steering angle of the vehicle. Thus, the automatic traction assistance system is capable of increasing maneuverability and traction in the drive axle when the vehicle experiences a sever turn. Hence, it enhances the life of tire by drastically reducing shoulder scrub and wear of the tire. Also, it is economical for both OEMs (i.e. low over all production cost) and users (i.e. less investment, operating and maintenance cost).
[00101] The present invention is a fully automatic traction assistance or control system which is used to extend the tire life of the vehicle having non-steer lift axle (or air suspension) and to control the traction of the vehicle. This automatic traction assistance or control system works based on the movement of the steering system of the vehicle. Especially, the automatic traction assistance or control system controls the air pressure of the ride air springs of the non-steer lift axle based on the steering angle of the vehicle. The automatic traction assistance or control system is controlled and operated by the steering system of the vehicle, which is the scope of the present invention. The steering of the vehicle may be taken as inputs from either front axles steering linkages (i.e., drop arms, drag links, steering arms etc.,) or electrical or electronic signals such as steering sensors, electrical limit switches, etc. Therefore, the present invention is not limited to the embodiments here in before described which may be varied in both construction and detail within the scope of the appended claims. Many modifications and other embodiments of the invention may come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. In addition, some changes (such as adding new valves and deleting few valves) may be made to these specific embodiments, and such modifications are contemplated by the principle of the present invention. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.

WE CLAIM:
1. An automatic traction assistance system (14) being operated by a steering mechanism
(48) based on a steering angle of a vehicle having twin steer axles and a lift axle (1) that is arranged with a pair of ride air springs (10) and a pair of lift air springs (11), comprising:
a first direction control valve (DCV1, 22) pneumatically operated to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn;
a second direction control valve (DCV2, 23) electrically connected and operated by a traction switch (TS, 18) to provide a pneumatic signal to the first DCV1 (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1);
a leveling valve (LV, 21) secured to a vehicle frame (4) and pivotally attached to a tie rod link (47) of the steering mechanism (48) for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or supply compressed air from a primary air tank (34) to the ride air springs (10);
a linkage mechanism (52) secured on a swinging bracket assembly (63) for pivotally connecting a lever (61) of the leveling valve (21) and the tie rod link (47) connected between first and second drop arms of the steering mechanism (48); and
a quick release valve (QRV1, 27) connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle
(0-
2. The system as claimed in claim 1, wherein the leveling valve (21) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (61) of the leveling valve (21) is connected to one end of the swinging bracket assembly (63) through a valve linkage assembly (62), where other end of the swinging bracket assembly is pivotally connected with the valve bracket (60).
3. The system as claimed in claim 1, wherein the linkage mechanism (52) is connected to the swinging bracket assembly (63) and a steering linkage assembly (64) that is connected to the tie rod link (47) through a clamp assembly (28).

4. The system as claimed in claim 1, wherein the leveling valve (21) is fluidly connected in between the primary air tank (34) and the second DCV2 (23) such that the leveling valve controls the operation of the first DCV1 (22) to fully deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23).
5. The system as claimed in claims 1 and 4, wherein the lever (61) of the leveling valve (21) is operated through the linkage mechanism (52) according to the movement of steering mechanism (48) for controlling air pressure of the ride air springs (10) of the lift axle (1). which fully deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn.
6. The system as claimed in claim 1, wherein the second DCV2 (23) is fluidly connected between the first DCV1 (22) and the leveling valve (21), and electrically connected with an ignition switch (17) through the traction switch (18).
7. The system as claimed in claims 1 and 6, wherein the traction switch (18) is electrically connected between a vehicle battery through the ignition switch (17) and an electrical terminal of a solenoid of the second DCV2 (23) in order to activate or deactivate the second DCV2 (23).
8. The system as claimed in claim 1, wherein the quick release valve (27) is fluidly connected between the first DCV1 (22) and the ride air springs (10) such that the operation of quick release valve is controlled by the leveling valve (21) through the second DCV2 (23) in order to fully deflate the ride air springs to lift the lift axle (1) when the vehicle reaches the
desired steering angle (49) during sever turn.
9. The system as claimed in claim 1, wherein the desired steering angle (49) of the vehicle
is preset within a maximum steering angle of a vehicle wheel at its steered direction.

10. An automatic traction assistance system (14a) being operated by a steering mechanism
(48) based on a steering angle of a vehicle having twin steer axles and a lift axie (1) that is
arranged with a pair of ride air springs (10) and a pair of lift air springs (11), comprising:
a first direction control valve (DCV1, 22) pneumatically operated to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn;
a second direction control valve (DCV2, 23) electrically connected and operated by a traction switch (TS, 18) to provide a pneumatic signal to the first DCV1 (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1);
a leveling valve (LV, 21) secured to a vehicle frame and pivotally attached to a tie rod link (47) of the steering mechanism (48) for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or supply compressed air from a primary air tank (34) to the ride air springs (10);
a linkage mechanism (52) secured on a swinging bracket assembly (63) for pivotally connecting a lever (61) of the leveling valve (21) and the tie rod link (47) connected between first and second drop arms of the steering mechanism (48);
a pressure limiting valve (PLV, 51) to limit air pressure in the ride air springs (10) for partial deflation of the ride air springs (10) when the vehicle reaches the desired steering angle
(49) during sever turn;
a first quick release valve (QRV1, 27) connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle (1); and
a second quick release valve (QRV2, 50) connected between the pressure limiting valve (51) and the first DCVI (22) to exhaust air from an exhaust line (65) extended from the first DCV1 (22).
11. The system as claimed in claim 10. wherein the pressure limiting valve (51) is fluidly connected between the primary air tank (34) and an inlet port (33) of the first DCV1 (22) through the second QRV2 (50).

12. The system as claimed in claims 30 and 11, wherein when the vehicle reaches the desired steering angle (49) during sever turn, the leveling valve (21) interrupts the supply of compressed air to the ride air springs (10) through the second DCV2 (23) and simultaneously, the pressure limiting valve (51) controls the second QRV2 (50) and the first DCV1 (22) such that air pressure is maintained in the ride air springs (10) for partially deflating the ride air springs (10).
13. The system as claimed in claim 10, wherein the leveling valve (21) is fluidly connected in between the primary air tank (34) and the second DCV2 (23) such that the leveling valve controls the operation of the first DCV1 (22) to fully or partially deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23).
14. The system as claimed in claims 10 and 13, wherein the lever (61) of the leveling valve (21) is operated through the linkage mechanism (52) according to the movement of steering mechanism (48) for controlling air pressure of the ride air springs (10) of the lift axle (1), which fully or partially deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn.
15. The system as claimed in claim 10, wherein the leveling valve (21) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (61) of the leveling valve (21) is connected to one end of the swinging bracket assembly (63) through a valve linkage assembly (62), where other end of the swinging bracket assembly is pivotally connected with the valve bracket (60).
16. The system as claimed in claim 10, wherein the linkage mechanism (52) is connected to the swinging bracket assembly (63) and a steering linkage assembly (64) that is connected to the tie rod link (47) through a clamp assembly (28).
17. The system as claimed in claim 10, wherein the desired steering angle (49) of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.

18. An automatic traction assistance system (14b) being operated by a steering mechanism (48) based on a steering angle of a vehicle having twin steer axles and a lift axle (1) that is arranged with a pair of ride air springs (10) and a pair of lift air springs (11), comprising:
a first direction control valve (DCV1, 22) pneumatically operated to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn;
a second direction control valve (DCV2, 23) electrically connected and operated by a traction switch (TS, 18) to provide a pneumatic signal to the first DCV1 (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1);
a leveling valve (LV, 21) secured to a vehicle frame and pivotaliy connected with at least one of first and second drop arms (54a, 54b) of the steering mechanism (48) for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or supply compressed air from a primary air tank (34) to the ride air springs (10);
a linkage mechanism (52) secured on a swinging bracket assembly (63) and pivotaliy connected between a lever (61) of the leveling valve (21) and the first drop arm (54a) or second drop arm (54b) of the steering mechanism (48);
a pressure limiting valve (PLV, 51) to limit air pressure in the ride air springs (10) for partial deflation of the ride air springs (10) when the vehicle reaches the desired steering angle (49) during sever turn;
a first quick release valve (QRV1, 27) connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle (]'); and
a second quick release valve (QRV2, 50) connected between the pressure limiting valve (51) and the first DCV1 (22) to exhaust air from an exhaust line (65) extended from the first DCVI (22).
19. The system as claimed in claim 18, wherein the leveling valve (21) is pivotaliy connected with the first drop arm (54a) or the second drop arm (54b) through the linkage mechanism (52) and the swinging bracket assembly (63).

20. The system as claimed in claims 18 and 19, wherein the leveling valve (21) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (61) of the leveling valve (21) is connected to one end of the swinging bracket assembly (63) through a valve linkage assembly (62), where other end of the swinging bracket assembly (63) is pivotally connected with the valve bracket (60).
21. The system as claimed in claim 18, wherein the linkage mechanism (52) is connected to the swinging bracket assembly (63) that is connected to the first drop arm (54a) or second drop arm (54b) of the steering mechanism (48) through a steering linkage assembly (64).
22. The system as claimed in claim 18, wherein the lever (61) of the leveling valve (21) is operated through the linkage mechanism (52) according to the movement of the first drop arm (54a) or second drop arm (54b) of the steering mechanism (48) such that the leveling valve (21) controls the operation of the first DCV1 (22) to fully or partially deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23) with respect to the desired steering angle (49) attained by the vehicle during sever turn.
23. An automatic traction assistance system (14c) being operated by a steering mechanism (48) based on a steering angle of a vehicle having twin steer axles and a lift axle (1) that is arranged with a pair of ride air springs (10) and a pair of lift air springs (11), comprising:
a first direction control valve (DCV1, 22) pneumatically operated to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn;
a second direction control valve (DCV2, 23) electrically connected and operated by a traction switch (TS, 18) to provide a pneumatic signal to the first DCV1 (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1);
a critical steering angle valve (80) secured to a vehicle frame and pivotally attached to a tie rod link (47) of the steering mechanism (48) for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or supply compressed air from a primary air tank (34) to the ride air springs (10);

a pressure limiting valve (PLV, 51) to limit air pressure in the ride air springs (10) for partial deflation of the ride air springs (10) when the vehicle reaches the desired steering angle (49) during sever turn;
a first quick release valve (QRV1, 27) connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle (1); and
a second quick release valve (QRV2, 50) connected between the pressure limiting valve (51) and the first DCV1 (22) to exhaust air from an exhaust line (65) extended from the first DCVI (22).
24. The system as claimed in claim 23, wherein the critical steering angle valve (80) having a lever (81) that is pivotally attached to the tie rod link (47) connected between first and second drop arms of the steering mechanism (48) through a linkage assembly (82) and a bracket assembly (28).
25. The system as claimed in claims 23 and 24, wherein the lever (81) of the critical steering angle valve (80) is operated through the linkage assembly (82) according to the movement of tie rod link (47) of the steering mechanism (48) for controlling air pressure of the ride air springs (10) of the lift axle (1), which fully or partially deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn.
26. The system as claimed in claims 23 and 24, wherein the critical steering angle valve (80) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (81) of the critical steering angle valve (80) is pivotally connected to one end of the linkage assembly (82), where other end of the linkage assembly (82) is connected to the tie rod link (47) through the bracket assembly (28).
27. The system as claimed in claim 23, wherein the critical steering angle valve (80) is fluidly connected in between the primary air tank (34) and the second DCV2 (23) such that the critical steering angle valve (80) controls the operation of the first DCV1 (22) to fully or partially

deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23).
28. The system as claimed in claim 23, wherein the desired steering angle (49) of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.
29. An automatic traction assistance system (14d) being operated by a steering mechanism
(48) based on a steering angle of a vehicle having twin steer axles and a lift axle (1) that is
arranged with a pair of ride air springs (30) and a pair of lift air springs (11), comprising:
a first direction control valve (DCV1. 22) pneumatically operated to deflate the ride air springs (10) of the lift axle (1) when the vehicle reaches a desired steering angle (49) during sever turn;
a second direction control valve (DCV2, 23) electrically connected and operated by a traction switch (TS, 18) to provide a pneumatic signal to the first DCVI (22) in order to supply compressed air to the ride air springs (10) or to deflate the lift air springs (11) of the lift axle (1);
a critical steering angle valve (80) secured to a vehicle frame (4) and pivotally connected with at least one of first and second drop arms (54a, 54b) of the steering mechanism (48) for controlling the first DCV1 (22) in order to deflate the ride air springs (10) or supply compressed air from a primary air tank (34) to the ride air springs (10);
a pressure limiting valve (PLV, 51) to limit air pressure in the ride air springs (10) im-partial deflation of the ride air springs (10) when the vehicle reaches the desired steering angle
(49) during sever turn;
a first quick release valve (QRV1, 27) connected to the ride air springs (10) to rapidly exhaust the air from the ride air springs (10), which deflates the ride air springs (10) to lift the lift axle (1); and
a second quick release valve (QRV2, 50) connected between the pressure limiting valve (51) and the first DCV1 (22) to exhaust air from an exhaust line (65) extended from the first DCVI (22).
30. The system as claimed in claim 29, wherein the critical steering angle valve (80) is secured to a valve bracket (60) attached to the vehicle frame (4) in such a way that the lever (81)

of the critical steering angle valve (80) is pivotalfy attached to the first drop arm (54a) or the second drop arm (54b) through a linkage assembly (82).
31. The system as claimed in claims 29 and 30, wherein the lever (81) of the critical steering angle valve (80) is operated through the linkage assembly (82) according to the movement of the first drop arm (54a) or second drop arm (54b) of the steering mechanism (48) for controlling air pressure of the ride air springs (10) of the lift axle (1), which fully or partially deflates the ride air springs with respect to the desired steering angle (49) attained by the vehicle during sever turn.
32. The system as claimed in claim 29, wherein the critical steering angle valve (80) is ffuidly connected in between the primary air tank (34) and the second DCV2 (23) such that the critical steering angle valve (80) controls the operation of the first DCV1 (22) to fully or partially deflate the ride air springs (10) by supplying compressed air to the ride air springs (10) through the second DCV2 (23).
33. The system as claimed in claim 29, wherein the desired steering angle (49) of the vehicle is preset within a maximum steering angle of a vehicle wheel at its steered direction.