TECHNICAL FIELD
[0001] The present invention relates to a three-wheeled vehicle. More
particularly, the present invention relates to a steering system for the three-wheeled vehicle.
BACKGROUND
[0002] In many of the developing & under developed countries, a motor
vehicle particularly a three-wheeled automotive vehicle is a significant mode of public transportation. It is vastly used as a point to point mode of transport in rural and urban areas. Due to a single wheel at front, the handling mostly depends on a steering system of the vehicle. The steering system of the vehicle is used to steer a front wheel of the vehicle as well as support the vehicle for providing a smooth ride. It is also desirable to damp forces exerted on the front wheel of the vehicle in order to keep them from being transferred to the vehicle body, which, in turn, results in a more comfortable driving experience.
[0003] Generally, in order to minimize the forces transmitted to the vehicle,
the steering and suspension system of two-wheeled vehicle and four-wheeled vehicle are equipped with a steering -damper. The steering damper reduces undesirable movement, known as bump steer that otherwise might be transmitted to the steering wheel when one of the front tires encounters a road surface irregularity.
[0004] In an existing motor vehicle steering system, a hydraulic steering
damper apparatus is arranged to produce a damping force to prevent the oscillation of handling due to wobbling upon external perturbations. Also, the steering damper assemblies are known to reduce the shock sensitivity of the steering system.
[0005] In an existing arrangement of the steering damper on the vehicle, the
steering damper is mounted on or integrated with a vehicle which has pair of handlebars which are rotatable or pivotal about an axis and are connected to a steerable wheel. Generally, the steering damper is mounted with its shaft of the

vane assembly coaxial with or connected to the axis about which the pair of handlebars rotates, rotatable in synchronism with the rotation of the pair of handlebars and the steering rotation of the steerable wheel.
[0006] In a known steering system for the two-wheeled and four-wheeled
vehicle, a hydraulic steering damper apparatus is arranged to produce a damping force. The hydraulic steering damper apparatus prevents the oscillation of handling due to kick-back upon externa] perturbations.
[0007] In'another known-steering system, the wheels of a motor vehicle may
include tie rods that connect right- and left-hand steering knuckles so that any given input through a drag link is transferred to both wheels simultaneously without loss of motion. The steering damper is interconnected between an axle of the motor vehicle and one of the tie rods.
[0008] In another conventional steering system, the two-wheeled vehicle is equipped with the steering damper to enhance the steering of operability between the vehicle body frame and under bracket when transmitted from the road surface such as a vibration is applied to the handlebar while driving, or discomfort, because it may not smoothly performed steering operation, in order to suppress such vibration.
[0009] In a known conventional steering system of the four-wheeled vehicles
the steering damper detects load applied to the front wheels of the vehicle, so as to increase the damping force on the basis of reduction of the load.
[00010] Typically, the three-wheeled vehicles are not equipped with the steering damper to damp forces exerted on the front wheel of the vehicle. Many of the existing steering system for the two-wheeled .vehicle and four-wheeled vehicle are not ideal for three-wheeled vehicle as due to the single wheel at front and a pair of wheels at rear, the handling is mostly depended on the operability of a handlebar, a front fork and the front wheel. The forces acting on the front fork are transmitted to the rider's body. During normal running on road, road irregularities can excite wobble mode, thus causing the vehicle unsafe for riding. The wobble

mode produced has significance effect on vehicle handling and needs to be eliminated in the operating speed range for better handling of the vehicle by introducing the steering damper in the steering system of the three-wheeled vehicle which can be easily and safely manipulated by the rider while the vehicle is in motion.
BRIEF DESCRIPTION OF THE DRAWINGS
[00011] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[00012] Fig.l illustrates a side perspective view of an exemplary three-wheeled vehicle, in accordance with one embodiment of the present subject matter.
[00013] Fig.2 illustrates the perspective view of the three-wheeled vehicle as per one embodiment of the present invention.
[00014] Fig.3. illustrates the perspective view of a steering system of the three-wheeled vehicle according to one embodiment of the present invention.
[00015] Fig.4. illustrates the perspective view of a steering damper placed between a frame and the steering system of the three-wheeled vehicle.
[00016] Fig.5 illustrates a rear perspective view of the steering system as per one embodiment of the present invention.'
[00017] Fig.6. shows a fragmentary perspective view illustrating the steering . damper as per one embodiment of the present invention.
[00018] Fig.7. is an enlarged exploded perspective view of the steering damper placed between the frame and the steering system as per one embodiment of the present invention.
[00019] Fig.8. is a perspective view of the steering damper secured in a mounting bracket as per one embodiment of the present invention.

[00020] Fig.9. is a perspective view of the mounting bracket with a mounting arm and a supporting arm as per one embodiment of the present invention.
[00021] Fig.10. is a illustrates a exploded perspective view of the mounting bracket with said mounting arm and said supporting arm as per one embodiment of the present invention.
DETAILED DESCRIPTION
[00022] A steering system of a two-wheeled and a four-wheeled vehicle are equipped with a steering damper to avoid or suppress fluctuations in the steering system. The steering damper has played a very beneficial role in enhancing vehicle safety. Though many vehicles are not originally equipped with stabilizers by the manufacturer, however safety need requires arrangement of the steering damper on the vehicle. The steering damper is a damping device designed to inhibit an undesirable, uncontrolled movement or oscillation of a vehicle steering system, a phenomenon known as wobble.
[00023] In a known steering system for a two-wheeled vehicle, the steering damper arrangement comprises the steering damper having a cylinder with respect to which a piston rod moves in accordance with a steering angle imposed by the rider on the steering system. The steering damper is actuated by a connecting rod adapted to connect the damper cylinder to the steering assembly, through hinge-mountings at the ends of the connecting rod.
[00024] Typically, a three-wheeled vehicle is a significant mode of public transportation. The vehicle sometime is also used to transport goods from one place to other. Both passenger and goods carrying capacity of the three-wheeled vehicle add a whole bunch of weight to the front of the vehicle. The heavy load on the vehicle makes the steering uncontrollable and since, the vehicle has a single wheel at front, the handling is mostly dependent on the steering system of the vehicle. Also, during normal running on road, road irregularities can excite a phenomenon called wobbling mode which can result in unsafe riding.

[00025] With the above objectives in view, the present invention discloses the steering system of the three-wheeled vehicle with said steering damper placed on the vehicle between the frame and the steering system. The steering damper eliminates the vibrations and the wobbling in the operating speed range for better handling of vehicle and absorbs the side-to side motion in a vehicle's suspension, stopping vibration, wheel shimmy and bump steer. The steering damper not only controls the wobbling but helps in steering with less steering effort required.
[00026] As per one embodiment of the present invention, the three-wheeled vehicle comprises the frame having a ladder like structure. The frame of the three-wheeled vehicle consists of a front frame and a rear frame. The front frame includes a steering system comprising a head tube, a pair of handlebars and a fork holding the front wheel, a steering rod mounted swiveling through said head tube about a steering axis and connected on the one hand to said pair of handlebars and on the other hand to said fork and a lever being pivotally anchored to the steering rod. The rear frame includes the rider, the engine, chassis, body, and the seat and rear wheels. The rear frame and the front frame are assembled together at the steering axis by a revolute pair.
[00027] During the motion of the vehicles, the tires are free to sideslip so they produce lateral forces, which are a linear function of the sideslip angles. These forces are considered to be restoring forces. The steering axis is considered to be constrained so that it can't move laterally. Thus, the vehicle has two decoupled systems each having only one degree of freedom. First, the front frame oscillating around the steering axis on which the lateral front tire force acts as a restoring force and second the rear frame oscillating around the steering axis on which the lateral rear tire force acts as a restoring force. Thus, two oscillation modes are produced, the one as a wobble mode produced by the oscillation of the front frame around the steering axis called the wobble mode and the other weave mode produced by the oscillation of the rear frame around the steering axis called the weave mode. As per one embodiment of the present invention, the steering damper is placed in the three-wheeled vehicle to damp the lateral force exerted on the front

wheel of the vehicle and results in a more comfortable driving experience. According to one embodiment of the invention, the steering damper in the three-wheeled vehicle operates using auxiliary hydraulic power, in such a manner that the forces which the driver applies when steering the vehicle are always sufficiently low and thus improve the handling, road feel, and stability, prevent steering wobble and bump-steer and reduce the driver fatigue.
[00028] As per one embodiment of the present invention, the steering damper is a cylinder housing the piston rod. An interior of cylinder may be filled with damping fluid, oil, gas spring or said gas spring that is filled with oil. During operation of the motor vehicle, any feedback of road input to the steering damper is damped by movement of the piston rod through the damping fluid. The piston rod may include various thin discs and coil springs schematically represented at, respectively that allow damping fluid to pass there through and assist in damping feedback from the road. As per one embodiment of the present invention, the steering damper in the three-wheeled vehicle is provided with a damper adjustment mechanism. The steering damper adjustment is done manually by turning a knob on the steering damper and requiring the rider to let go of the handlebar to make the adjustment. The adjustment for the knob can be done as per from low to high damping options. As per one embodiment of the present invention, the damping force can be adjustable based on the severity of the wobble mode.
[00029] The present invention relates generally to the three-wheeled vehicle steering system and, in particular, to the steering damper arrangement on the three-wheeled vehicle. As per one embodiment of the present invention, the steering damper is arranged below the dashboard reinforcement assembly and placed between the frame and the steering system of the three-wheeled vehicle.
[00030] Although the present invention has been exemplified for the hydraulic steering damper, it is not restricted only for the hydraulic steering damper. Application of the present invention may be extended to a gas spring steering damper and the gas spring that is filled with oil.

[00031] Exemplary embodiment detailing features of the three-wheeled vehicle, in accordance with the present invention will be described hereunder. The embodiments described herein apply to the three-wheeled vehicle powered by an ■ internal combustion engine. However, the present invention is not restricted in its application and is also applicable to vehicles employing the drive motor or either by the internal combustion engine or the drive motor selectively or by the internal combustion engine alone.
[00032] The three wheeled automotive vehicle is mainly, but not solely, used as a passenger carrier. It is to be noted that "front" and "rear", and "left" and "right" wherever referred to in the ensuing description, refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the vehicle and looking forward. Furthermore, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers generally to a side to side, or left to right axis relative to the vehicle. Various other features of the three-wheeled vehicle according to the present subject matter here will be discernible from the following further description thereof, set out hereunder.
[00033] Fig. 1. illustrates a side perspective view of an exemplary three-wheeled vehicle (10), in accordance with an embodiment of the present subject matter. The vehicle (10) has the frame (FT), which includes a head tube (27), a main tube assembly (26) (shown in Fig.2) extending rearward from the head tube (27) (shown in Fig. 3, Fig.6 and Fig.7). The vehicle (10) has a front cowl (13) positioned in the anterior portion of the head tube (27). A wind shield (12) is mounted to the front cowl (13). A floorboard (18) is extending from the bottom portion of the front cowl (13) to the rearward direction of the vehicle (10), supported by the main frame assembly (26). A handle bar assembly (14) is rptatably supported by the head tube (27), positioned behind the front cowl (13). A steering system (100) comprises of the handlebar assembly (14) including said pair of handlebars (22), (23) and the fork (35) holding the front wheel (16). A front fender (15) is above the front wheel (16), covering at least a portion of the front wheel (16). A bottom portion of a body panel (21) is connected to the posterior portion of the floorboard (18). A pair of real wheels (20) are connected

to a swing arm through one or more suspension(s), the swing arm is in turn connected to the frame (Fr). The rear suspension includes a shock absorber and a suspension spring unit (39) mounted to the frame (Fr) of the vehicle (10). A hood (11) connects a top portion of the front cowl (13) and a top portion of the body panel (21). The vehicle (10) is longitudinally divided into two portions along the line X-X'; a front portion (F) has a driver's seat (17) while a rear portion (R) has at least one passenger seat (19) with a seating capacity of one or more passengers. The driver seat (17) is positioned in a posterior portion to the handle bar assembly (14). A partition wall is positioned along the line X-X' extending in the lateral direction of the vehicle (10). The driver's seat (17) comprises a seat base (17a) and a fixed backrest (17b). The driver operates the vehicle (10) in a sitting position by sitting on the seat base (17a).
[00034] Fig.2 illustrates the perspective view of the three-wheeled vehicle (10) as per one embodiment of the present invention. The steering system (100) comprises of the handlebar assembly (14) including said pair of handlebars (22), (23) and the fork (35) (shown in Fig.6) holding the front wheel (16). As per one embodiment of the present invention, the steering damper (101) is arranged below the dashboard assembly (111) and is disposed between the steering system (100) and the frame (Fr) of the three-wheeled vehicle (10).
[00035] Fig.3. illustrates the perspective view of a steering system (100) of the three-wheeled vehicle (10) according to one embodiment of the present ' invention. The three-wheeled vehicle (10) comprises the frame (Fr) having said ladder like structure and includes the head tube (27) (shown in Fig.3, Fig.6, and Fig. ,7), the front wheel (16) dirigibly supported by said frame (Fr) and a pair of rear wheels (20) carried by said frame (Fr). The steering system (100) includes pair of handlebars (22), (23) and the fork (35) (shown in Fig.6) holding the front wheel (16), a steering rod (24) mounted.swivelling through said head tube (27). about a steering axis (BB) and connected on the one hand to said pair of handlebars (22), (23) and on the other hand to said fork (35), and a lever (36) being pivotally anchored to the steering rod (24). In one embodiment, the

dashboard reinforcement assembly (34) including a circular cross-section portion (37) (shown in Fig.7) is adapted to receive said steering rod (24) extending through said head tube (27). As per one embodiment of.the present invention, the steering damper (101) is placed between the head tube (27) and the steering system (100).
[00036] Fig.4. illustrates the perspective view of the steering damper (101) placed between the frame (Fr) and the steering system (100) of the three-wheeled vehicle (10). The steering damper (101) is secured to the frame (Fr) through a mounting bracket (113) (shown in Fig.8). The mounting bracket (113) comprises of a mounting arm (103) and a supporting arm (107) (shown in Fig.8). The steering damper (101) is secured in the supporting arm (107) of said mounting bracket (113).In one embodiment, said mounting bracket (113) is detachably attached to the head' tube (27) of the frame (Fr) through the 'mounting arm (103).The supporting arm (107) is detachably attached to said mounting arm (103) through a ball joint (108). As per one embodiment of the present invention, the dashboard reinforcement assembly (34) comprises of a connecting member (28) and at least one bracket member (29). The dashboard reinforcement assembly.(34) is attached to the head tube (27) of the frame (Fr) of the three-wheeled vehicle (10) through said at least one bracket member (29). The mounting arm (103) of the mounting bracket (113) is detachably attached to said at least one bracket member (29). Thus, the steering damper (101) is detachably attached to said head tube (27) of the three-wheeled vehicle (10) through the mounting arm (103) of the mounting bracket (113).
[00037] Fig.5 illustrates a rear perspective view of the steering system (100) as per one embodiment of the present invention. The steering damper (101) arranged below the dashboard assembly (111) (shown in Fig.2) and being disposed between the steering system (100) and the frame (Fr) of the three-wheeled vehicle (10). The dashboard reinforcement assembly (34) (shown in Fig.7) comprises of the connecting member (28) and said at least one bracket member (29). The dashboard reinforcement assembly (34) forms a cross-section

portion (37) (shown in Fig.7) adapted to receive steering rod (24) and is detachably attached to the head tube (27) of the three-wheeled vehicle (10). The mounting arm (103) of the mounting bracket (113) is attached to the head tube (27) through the dashboard reinforcement assembly (34). The steering damper (101) is secured in the supporting arm (107) of the mounting bracket (113) and the mounting arm (103) is detachably attached to said dashboard reinforcement . assembly (34). Thus, said steering damper (101) placed between the steering system (101) and frame (Fr) of the three-wheeled vehicle (10) is detachably attached to the head tube (27) through the mounting arm (103) of the mounting bracket (113) wherein said mounting arm (103) is detachably attached to the dashboard reinforcement assembly (34).
. [00038] Further in Fig.5, as per one embodiment of the present invention, the steering damper (101) is arranged below the dashboard" assembly (111) such as being disposed between the steering damper (101) and the frame (Fr) of the three-wheeled vehicle (10). The steering damper (101) operates under a principle that an internal hydraulic valving readjusts the amount of shock or impact that would have been received through the pair of handlebars (22), (23). The mounting arm (103) of the mounting bracket (113) which connects the steering damper (101) to the frame (Fr) reacts instantaneously, absorbing any unwanted movement. The steering damper (101) is adjustable through the damper adjustment mechanism (112) for high speed and low speed impacts via the knob (not shown).
[00039] Fig.6. shows a fragmentary perspective view illustrating the steering damper (101). As per one embodiment of the present invention, the lever (36) being pivotally anchored to the steering rod (24) of the steering system (100). The steering damper (101) is detachably attached to the head tube (27) at a first attachment point (106) and pivotally connected to the lever (36) at a second attachment point (104). The lever (36) can be swiveled with one or more steering bearings (31) about the steering axis (BB) of the steering system (100).

[00040] Further in Fig.6, referring to one embodiment of the present invention , the steering system (100) for the three-wheeled vehicle (10) comprises of the steering system (100) comprising said pair of handlebars (22), (23) and the fork (35) holding the front wheel (16), the steering rod (24) mounted swivelling through said head tube (27) about a steering axis (BB) and connected on the one hand to said pair of handlebars (22), (23) and on the other hand to said fork (35), and the lever (36) being pivotally anchored to the steering rod (24). The pair of handlebars (22), (23) are rotatable or pivotal in synchronism with the steerable front wheel (16) either to steer the front wheel (16) or to be rotated by the front wheel (16) when the front wheel (16) undesirably contacts an obstruction over which the vehicle (10) is moving. The steering damper (101) is placed between the steering system (100) and the frame (Fr) of the three-wheeled vehicle (10) and is detachably attached to the frame (Fr) through the mounting bracket (113). . . .
[00041] Fig.7. is an enlarged exploded perspective view of the steering damper (101) placed between the frame (Fr) and the steering system (100). As per one embodiment of the present invention, the three-wheeled vehicle (10) includes the steering damper (101) disposed between the steering system (100) for steering the front wheel (16) and the frame (Fr) through the first attachment point (106) . and the second attachment point (104). The steering damper (101) is detachably attached to said head tube (27) at the first attachment point (106) through the mounting bracket (113). As per one embodiment of the present invention, the dashboard reinforcement assembly (34) comprises of the connecting member (28) and said at least one bracket member (29). In one embodiment, said at least one bracket member (29) is connected to the connecting member (28) in a manner to form said circular cross-section portion (37) for receiving the steering rod (24) and thus supporting the dashboard assembly (111). The dashboard reinforcement assembly (34) through said at least one bracket member (29) is detachably attached to said head tube (27) through at least one fastener (30), (33), (38) and at least one bolt hole (32). The mounting bracket (113) through the mounting arm (103) is attached to said at least one bracket member (29) by a locater. Thus, said first attachment point (106) is a locater joining the mounting arm (103) of said

mounting bracket (113) to the dashboard reinforcement assembly (34). The steering damper (101) is pivotally connected to the lever (36) at the second attachment point (104) about said steering axis (BB) of said steering rod (24) for generating the damping force for a turning operation of the steering mechanism. The lever (36) can swung to the left or to the right for steering the front wheel (16) though the elongated holes (not shown) provided at a top potion of the steering rod (24) to permit the swinging movement of the lever (36). The first attachment point (104) is a ball joint (105) and attaching said steering damper to the steering system (100) through the lever (36) being pivotally anchored to the steering rod (24) about the steering axis (BB). The mounting bracket (113) comprises of the mounting arm (103) and the supporting arm (107). The supporting arm (107) attached to said mounting arm (103) through the ball joint (108) (shown in Fig.9). The steering, damper (101) is secured.in the supporting arm (107) of said mounting bracket (113) and is attached to said head tube (27) through the mounting arm (103) of the mounting bracket (113).The first attachment point (106) is a locater and the second attachment point (104) comprises the ball joint (105).
[00042] Further in Fig.7, as per .one embodiment of the present invention, the steering damper (101) is a cylinder housing the piston rod (102). According to one embodiment of the present invention, the steering damper (101) is a hydraulic damper provided with the damper adjustment mechanism (112) by which the resistance to fluid flow and hence the damping afforded by the steering damper (101) can be adjusted. The resistance adjustment is made by manually turning the damping force adjustment-knob (not shown) and thus requiring the rider to let go of the pair of handlebars (22), (23) to make the adjustment. The steering damper (101) with the damper adjustment mechanism (112) provides even greater stability and allow the driver of the three-wheeled vehicle (10) to change the damping force settings as driving conditions change.
[00043] Fig.8. is a perspective view of the steering damper (101) secured in a mounting bracket (113) as per the present invention. According to one

embodiment of the present invention, the mounting bracket (113) comprises of the mounting arm (103) and the supporting arm (17). The steering damper (101) housing the piston rod (102) is secured in the supporting arm (103). The supporting arm (107) of the mounting bracket (113) is attached to the mounting . arm (103) through the ball joint (108).
[00044] Further in Fig.8, the steering damper (101) is attached to the lever (36) (shown in above figures) at the second attachment point (104) comprising in at least one end (110) (shown in Fig. 10) of the piston rod (102) of said steering damper (101).The mounting arm (103) is detachably attached to said at least one bracket member (29) through the locater at the first attachment point (106). The steering damper (101) is provided with the damper adjustment mechanism (112) having the knob (not shown) for manually adjusting the damping force.
[00045] Fig.9. is a perspective view of the mounting bracket (113) with the mounting arm (103) and the supporting arm (107) as per one embodiment of the present invention. The steering damper (101) housing the piston rod (102) is secured in the supporting arm (107) of the mounting bracket (113). The steering damper (101) is detachably attached to the head tube (27) at the first attachment point (106) and pivotally connected to the lever (36) at the second attachment ■ point (104) provided at one end (110) of the piston rod (102) of the steering damper (101). The supporting arm (107) is attached to the mounting arm (103) through the ball joint (108). The mounting arm (103) is detachably attached to the. head tube (27) through the dashboard reinforcement assembly (34). As per one embodiment of the present invention, the supporting arm (107) and the mounting arm (103) of said mounting arm (113) is attached by the ball joint (108).
[00046] Fig. 10. illustrates an exploded perspective view of the mounting bracket (113) with said mounting arm (103) and said supporting arm (107). As per one embodiment of the present invention, the steering damper (101) is attached to the head tube (27) through the mounting bracket (113). The mounting bracket (113) comprises of the supporting arm (107) for securing the steering damper (101) and the mounting arm (103) for detachably attaching to the head tube (27).

The first attachment point (106) is a locater by which the mounting arm (106) of the mounting bracket (113) is detachably attached to the at least one bracket member (29) to the.head tube (27). The second attachment point (104) forms the ball joint (105) in said at least one end (110) of said piston rod (102) through which the steering damper (101) is pivotally connected to the lever (36).
[00047] Advantageously, as per the present invention, the steering damper dampens steering oscillations and optimize the steering effort for better handling. As per one embodiment of the present invention, the steering damper is arranged below the dashboard reinforcement assembly and placed between the steering system and frame of the three-wheeled vehicle. Thus, such arrangement of the steering damper imparts an easy mounting with low maintenance cost. According to one embodiment of the present invention, the steering damper for the
three-wheeled vehicle is provided with the"damper adjustment mechanism and ""
hence adjustment of damping force as per high and low speed is done by the knob setting. As per one embodiment of the present invention, the steering damper dampens the shaking of the steering on account of roughness encountered on the terrain and eliminates the vibrations and the wobbling in the operating speed range for better handling of vehicle.
[00048] Improvements and modifications may be incorporated herein without deviating from the scope of the invention