FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A STEERING SYSTEM FOR A MULTI AXLE VEHICLE AND A METHOD OF
OPERATION THEREOF”
Name and Address of the Applicant:
TATA MOTORS LIMITED of Bombay house, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra, INDIA
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
Present disclosure, in general, relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to steering a multi axle vehicle. Further, embodiments of the present disclosure discloses a steering system for a multi axle vehicle.
BACKGROUND OF THE DISCLOSURE
Generally, vehicles such as buses, trucks, utility vehicles, goods transport, large motor homes, and other transportation vehicles are built to maximum allowable length to maximize their hauling capabilities while maintaining the benefits of a single-unit or a trailer attached vehicles. In some cases, there maybe also oversized vehicles that are used for transportation of special equipment which the general commercial vehicles may not be able to handle. These vehicles typically have a steering axle and steerable wheel assemblies at their front end and driving axles and wheel assemblies at their rear end. Due to the long length, the vehicles have a long wheel base, which is the distance between the forward most wheel axle and the rear most wheel axle. To accommodate the long wheel base, the vehicle is typically adapted to have a long turning radius and is difficult to maneuver around corners. In addition, the rear wheel assemblies of the vehicles do not follow the path of the front steerable wheel assemblies when the vehicle negotiates a corner such that the rear wheel assemblies substantially cut the corner. The long turning radius of the vehicle requires a large area for maneuvering the vehicle which is not generally available.
With advancements in technology, the vehicles have been incorporated with steering systems that include an auxiliary steering axle rearward of a front steering axle. The front and the auxiliary steerable wheels act in tandem to steer the front portion of the vehicle through a turn or to navigate a turn. These front and auxiliary steering axle arrangement provides additional stability for the front portion of the vehicle and improved tracking of the rear wheels during turning maneuvers. However, the dual steering axle system does not change the length of the vehicle's wheel base so low speed maneuvering of the vehicle around short radius corners or the like is difficult and cumbersome.

Further, with advancements in the automobile industry, vehicles have been incorporated with steering systems that include a rear steering axle to steer the rear wheels. The conventional rear steering axle and wheels are controlled by the vehicle's front steering axle. The rear steering axle is connected to the front axles with complex mechanisms which require complex construction and regular servicing. Further, the rear steering axles create unstable driving conditions during high speed maneuvering which is undesired.
Additionally, the conventional steering systems for steering the vehicles with long wheel base are prone to failure due to the complex mechanisms that causes difficulty in steering the vehicle and requires immediate servicing to drive or maneuver the vehicle, which is undesired.
Present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the known arts.
SUMMARY OF THE DISCLOSURE
One or more shortcomings of the prior art are overcome by a system and a method as claimed and additional advantages are provided through the system and the method as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure, a steering system for a multi axle vehicle is disclosed. The system includes a first circuit having at least one tandem pump configured to receive a fluid. The at least one tandem pump is adapted to deliver pressurized fluid at a predefined flow rate. Further, a first reservoir is fluidly connected to the at least one tandem pump and is adapted to store the fluid. A valve block is fluidly coupled to the at least one tandem pump and the first reservoir. The valve block is configured to selectively channelize the fluid to at least one first steering axle. Further, the system includes a second circuit having the at least one tandem pump and a second reservoir which is fluidly connected to the at least one tandem pump and is adapted to store the fluid. Additionally, a transfer manifold is fluidly coupled to the at least one tandem pump and the second reservoir. The transfer manifold is configured to selectively channelize fluid to at least one second steering axle. Furthermore, the system includes a control unit which is

communicatively coupled to the first circuit and the second circuit. The control unit is configured to selectively operate the at least one second steering axle based on vehicle speed and operation of the at least one first steering axle.
In an embodiment, the at least one tandem pump includes a primary pump fluidly connected between the first reservoir and the valve block. The primary pump is configured to supply pressurized fluid to the valve block. Further, the at least one tandem pump includes a secondary pump connected between the second reservoir and the transfer manifold. The secondary pump is configured to supply pressurized fluid to the transfer manifold.
In an embodiment, the at least one tandem pump is driven by a prime mover of the vehicle.
In an embodiment, the at least one first steering axle includes a steering gear unit, linkages and one or more hydraulic cylinders for steering wheels of the multi axle vehicle.
In an embodiment, the at least one first steering axle includes at least one first sensor to determine a steering angle of the at least one first steering axle.
In an embodiment, the first circuit comprises a flow control valve to control flow of the fluid from the at least one tandem pump to the valve block.
In an embodiment, the second circuit comprises a flow control valve to control flow of the fluid from the at least one tandem pump to the transfer manifold.
In an embodiment, the at least one second steering axle includes one or more hydraulic cylinders, configured to selectively steer the wheels connected to the at least one second steering axle.
In an embodiment, the at least one second steering axle includes at least one second sensor to determine a steering angle of the at least one second steering axle.
In one non-limiting embodiment of the present disclosure, a steering system for a multi axle vehicle is disclosed. The steering system includes a first circuit having at least one tandem pump configured to receive a fluid. The at least one tandem pump is adapted to deliver pressurized fluid at a predefined flow rate. Further, a first reservoir is fluidly connected to the at least one tandem

pump and is adapted to store the fluid. A valve block is fluidly coupled to the at least one tandem pump and the first reservoir. The valve block is configured to selectively channelize the fluid to at least one first steering axle. Furthermore, the steering system includes an auxiliary circuit having at least one auxiliary pump which is configured to receive the fluid. The at least one auxiliary pump is adapted to deliver the pressurized fluid at the predefined flow rate. Additionally, an auxiliary reservoir is fluidly connected to the at least one auxiliary pump. The auxiliary reservoir is adapted to store the fluid. Further, the valve block is fluidly coupled to the at least one auxiliary pump and the auxiliary reservoir and is configured to selectively channelize fluid to at least one first steering axle of the multi axle vehicle. At least one directional control valve in the valve block configured to selectively channelize the fluid from the auxiliary circuit into the at least one first steering axle corresponding to non-operating condition of the first circuit.
In one non-limiting embodiment of the present disclosure, a method for steering a multi axle vehicle is disclosed. The method includes operating at least one tandem pump in a first circuit to steer the at least one first steering axle of the multi axle vehicle. Further, a steering angle of the at least one first steering axle is received by a control unit from at least one first sensors. Further, the control unit is configured to determine speed of the multi axle vehicle and compare the speed of the multi axle vehicle with a threshold speed. Furthermore, the control unit is configured to actuate a transfer manifold defined in a second circuit on determination of the speed of the multi axle vehicle being less than the threshold speed. Additionally, the control unit is configured to regulate flow of fluid in the second circuit based on steering angle of the at least one first steering axle to steer the at least one second steering axle of the multi axle vehicle.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative

embodiments when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Fig. 1 illustrates a schematic view a steering system for a multi axle vehicle, in accordance with an embodiment of the present disclosure.
Fig. 2 illustrates a schematic view of a first circuit of the steering system, in accordance with an embodiment of the present disclosure.
Fig. 3 illustrates a schematic view of a second circuit of the steering system, in accordance with an embodiment of the present disclosure.
Fig. 4 illustrates a flow chart of a method for steering the multi axle vehicle, in accordance with an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which forms the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that, the conception and specific embodiments disclosed may be readily utilized as a basis for modifying other devices, systems, assemblies, mechanisms, methods and processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that, such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however,

that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non¬exclusive inclusions, such that a system or a device that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
In accordance with various embodiments of the present disclosure, a steering system for a multi axle vehicle is disclosed. The system may include a first circuit having at least one tandem pump configured to receive a fluid. The at least one tandem pump may be adapted to deliver pressurized fluid at a predefined flow rate. Further, a first reservoir may be fluidly connected to the at least one tandem pump and may be adapted to store the fluid. A valve block may be fluidly coupled to the at least one tandem pump and the first reservoir. The valve block may be configured to selectively channelize the fluid to at least one first steering axle. Further, the system may include a second circuit having the at least one tandem pump and a second reservoir which may be fluidly connected to the at least one tandem pump and is adapted to store the fluid. Additionally, a transfer manifold may be fluidly coupled to the at least one tandem pump and the second reservoir. The transfer manifold may be configured to selectively channelize the fluid to at least one second steering axle. Furthermore, the system may include a control unit which may be communicatively coupled to the first circuit and the second circuit. The control unit may be configured to selectively operate the at least one second steering axle based on vehicle speed and operation of the at least one first steering axle.
Further, the steering system for a multi axle vehicle may include an auxiliary circuit having at least one auxiliary pump which may be configured to receive the fluid. The at least one auxiliary pump may be adapted to deliver the pressurized fluid at the predefined flow rate. Additionally, an auxiliary reservoir may be fluidly connected to the at least one auxiliary pump. The auxiliary reservoir may be adapted to store the fluid. Further, the valve block may be fluidly coupled to the at least one at least one auxiliary pump and the auxiliary reservoir and may be configured to

selectively channelize fluid to at least one first steering axle of the multi axle vehicle. Additionally, the control unit is communicatively coupled to a t least one directional control valve in the valve block that may be configured to selectively channelize the fluid from the auxiliary circuit into the at least one first steering axle corresponding to non-operating condition of the first circuit.
Furthermore, a method for steering a multi axle vehicle is disclosed. The method may include operating at least one tandem pump in a first circuit to steer the at least one first steering axle of the multi axle vehicle. Further, a steering angle of the at least one first steering axle may be received by a control unit from at least one first sensors. Further, the control unit may be configured to determine speed of the multi axle vehicle and compare the speed of the multi axle vehicle with a threshold speed. Furthermore, the control unit may be configured to actuate a transfer manifold which may be defined in a second circuit on determination of the speed of the multi axle vehicle being less than the threshold speed. Additionally, the control unit may be configured to regulate flow of fluid in the second circuit based on steering angle of the at least one first steering axle to steer the at least one second steering axle of the multi axle vehicle.
The configuration of the system and the method of operating the system enables rear axle steering without reducing the stability of the vehicle at high speeds. Further, the auxiliary circuit in the steering system provides a fail-safe option which enables the steering system to operate even when the first circuit has failed.
Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals have been used to refer to the same or like parts. The following paragraphs describe the present disclosure with reference to Figs. 1-4. It is to be noted that the system and the method may be employed in any vehicle including but not limited to a passenger vehicle, a utility vehicle, commercial vehicles, and any other vehicle with multiple axles.
Fig. 1 is an exemplary embodiment of the present disclosure which illustrates a steering system (100) for a multi axle vehicle. For simplicity, a figure depicting the multi axle vehicle [hereafter referred to as vehicle] is not illustrated. The steering system (100) [hereafter referred to as system (100)] may include a first circuit (101) and a second circuit (102). The first circuit (101) may be

configured to operate at least one first steering axle (111) and the second circuit (102) may be configured to operate at least one second steering axle (112). In an embodiment, the at least one first steering axle (111) may be the axle positioned at a front portion of the vehicle that is capable of steering the vehicle. Further, the at least one second steering axle (112) may be the axles positioned in a rear portion of the vehicle that is capable of steering. The first steering axle (111) and the second steering axle (112) may include a steering gear unit (1) which may be connected to a steering wheel of the vehicle and one or more hydraulic cylinders (2) connected to wheels of the vehicle for steering the wheels of the multi axle vehicle. Further, the first steering axle (111) may include at least one first sensor [not shown in Figs] to determine a steering angle of the wheels in the first steering axle (111). Additionally, the at least one second steering axle (112) may include at least one second sensor [not shown in Figs] to determine a steering angle of the wheels in the at least one second steering axle (112).
Fig. 2 illustrates the first circuit (101) of the steering system (100). The first circuit (101) may include at least one tandem pump (3) which may be configured to receive a fluid and pressurize the fluid to a predefined pressure and may deliver the pressurized fluid at a predefined flow rate. In an embodiment, the predefined flow rate may correspond to a pressure which may be required to operate the steering gear unit (1) and the one or more hydraulic cylinders (2) that may be required for steering the wheels in the multi axle vehicle. Further, the first circuit (101) may include a first reservoir (4). The first reservoir (4) may be fluidly connected to the at least one tandem pump (3) and may be adapted to store the fluid which may be supplied to the at least one tandem pump (3). Furthermore, the first circuit (101) may include a valve block (5). The valve block (5) may be fluidly coupled to the at least one tandem pump (3) at one end and the first reservoir (4) at the other end. The valve block (5) may be configured to receive the fluid from the at least one tandem pump (3) and may selectively channelize the fluid to the at least one first steering axle (111). In an embodiment, the valve block (5) may be configured to channelize fluid to the steering gear unit (1) and the one or more hydraulic cylinders (2) provisioned in the at least one first steering axle (111) to steer the wheels.
In an embodiment, the valve block (5) may include at least one directional control valve [not shown in Figs], which may be configured to selectively select fluid flow path within the valve block (5).

In an embodiment, the at least one tandem pump (3) may be driven by a prime mover of the vehicle.
Fig. 3 illustrates the second circuit (102) of the steering system (100). The second circuit (102) may also include the at least one tandem pump (3) to pressurize the fluid to the predefined pressure and flow rate. Further, the second circuit (102) may include a second reservoir (6) which may be fluidly connected to the at least one tandem pump (3). Furthermore, the second circuit (102) may include a transfer manifold (7). The transfer manifold (7) may be fluidly coupled to the at least one tandem pump (3) and the second reservoir (6) may be configured to selectively channelize fluid to at least one second steering axle (112). In an embodiment, the transfer manifold (7) may be configured to channelize fluid to the one or more hydraulic cylinders (2) provisioned in the at least one second steering axle (112) to steer the wheels.
In an embodiment, the second circuit (102) comprises a flow control valve (8) to control flow of the fluid from the at least one tandem pump (3) to the transfer manifold (7).
In an embodiment, the at least one tandem pump (3) may include a primary pump which may be fluidly connected between the first reservoir (4) and the valve block (5). The primary pump may be configured to supply pressurized fluid to the valve block (5). Additionally, the at least one tandem pump (3) that may include a secondary pump which may be connected between the second reservoir (6) and the transfer manifold (7) which may be configured to supply the pressurized fluid to the transfer manifold (7).
Further, the steering system (100) may include a control unit (CU) which may be communicatively coupled to the first circuit (101) and the second circuit (102). In an embodiment, the control unit (CU) may be communicatively coupled to the at least one first sensor and the at least one second sensor and may be configured to receive signals corresponding to the steering angles of the wheels in the at least one first steering axle (111) and the at least one second steering axle (112), respectively. Furthermore, the control unit (CU) may be communicatively coupled to the valve block (5) and the transfer manifold (7) and may be configured to selectively operate the valve block (5) and the transfer manifold (7) to channelize the fluid into the at least one first steering axle (111) and the at least one second steering axle (112), respectively. Additionally, the control unit (CU) may be configured to receive signals corresponding to a speed of the vehicle from an

instrument cluster (12) or any other component of the vehicle capable of transmitting signals related to the speed of the vehicle.
The control unit (CU) may be configured to compare the speed of the vehicle with a threshold speed to selectively operate the transfer manifold (7) in the second circuit (102) to actuate the at least one second steering axle (112) to steer the corresponding wheels. In an embodiment, the threshold speed may be a preset value which may be corresponding to a low speed of the vehicle at which the vehicle and may remain stable upon turning of the wheels in the at least one second steering axle (112). The threshold speed may be pre-stored in the control unit (CU) during manufacturing or may be suitably varied based on user requirement. Further, the control unit (CU) upon detecting the vehicle speed to be less than the threshold speed, may operate the transfer manifold (7) to supply the fluid into the one or more hydraulic cylinders (2) provisioned in the at least one second steering axle (112) to steer the wheels. The steering angle of the wheels in the at least one second steering axle (112) may be based on the steering angle in the wheels of the at least one first steering axle (111) which may be determined by the control unit (CU) based on the signals received from the at least one first sensor and the at least one second sensor. Steering the vehicle with the at least one second steering axle (112) along with the at least one first steering axle (111) enables the vehicle to turn with a lower turning radius. In an embodiment, the steering angle of the wheels in the at least one second steering axle (112) may be opposite to the steering angle of the wheels in the at least one first steering axle (111). Furthermore, the amount of steering angle in the at least one second steering axle (112) may be proportional to the amount of steering angle in the at least one first steering axle (111). Additionally, the control unit (CU) may be configured operate the hydraulic cylinders (2) in the at least one second steering axle (112) based on the at least one second sensor. The control unit (CU) based on the signals from the at least one second sensor may determine the wheels of the at least one second steering axle (112) reaching the required amount of steering angle to regulate the fluid. Further, upon the vehicle attaining a speed greater than the threshold speed, the control unit (CU) may be configured to halt operation of the transfer manifold (7) and retain the wheels in the at least one second steering axle (112) without any steering angle thereby improving stability of the vehicle during turning maneuver at high speeds.

In an embodiment, the control unit (CU) may be configured to intimate the user or the driver of the non-operating condition of the second circuit (102) by an indication unit which may alert the driver or the user to fix the issue.
In an embodiment of the disclosure, the control unit (CU) may be a centralized control unit, or a dedicated control unit for the system (100). The control unit (CU) may also be associated with other control units including, but not limited to, a body control module (BCM), a central control module (CCM), a general electronic module (GEM), and the like. The control unit (CU) may be implemented by any computing systems that is utilized to implement the features of the present disclosure. In an embodiment, the control unit (CU) may include a receiving module which may be configured to receive the signals. Further, the control unit (CU) may include a processing module which may include at least one data processor for executing program components for executing user or system generated requests. The processing module may be a specialized processing module such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing modules, digital signal processing modules, etc. The processing module may include a microprocessor, and may be configured to receive data or signals from the receiving module. Furthermore, the control unit (CU) may include an activation module which may be configured to receive data or signals from the processing module and transmit the received signals to actuate or operate the components.
In some embodiments, the control unit (CU) may be disposed in communication with one or more memory devices (e.g., RAM, ROM etc.) via a storage interface. The storage interface may connect to memory devices including, without limitation, memory drives, removable disc drives, and the like. The memory device may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, redundant array of independent discs (RAID), solid-state memory devices, solid-state drives, etc.
Referring back to Fig. 2, which illustrates the first circuit (101) and an auxiliary circuit (103). The auxiliary circuit (103) may include at least one auxiliary pump (9) which may be configured to receive the fluid and pressurize the fluid to a predefined pressure and may deliver the pressurized fluid at the predefined flow rate. In an embodiment, the at least one auxiliary pump (9) may be driven by the prime mover of the vehicle or any other component of the vehicle capable of driving

the at least one auxiliary pump (9), for example, a gear box, an auxiliary gear box, motor and the like. Further, the auxiliary circuit (103) may include an auxiliary reservoir (10). The auxiliary reservoir (10) may be fluidly connected to the at least one auxiliary pump (9) and may be adapted to store the fluid which may be supplied to the at least one auxiliary pump (9). Furthermore, the auxiliary circuit (103) may include the valve block (5) such that the valve block (5) may be fluidly coupled to the at least one auxiliary pump (9) at one end and the auxiliary reservoir (10) at the other end. The valve block (5) may be configured to receive the fluid from the at least one auxiliary pump (9) and may selectively channelize the fluid to the at least one first steering axle (111). In an embodiment, the valve block (5) may be configured to channelize fluid to the steering gear unit (1) and the one or more hydraulic cylinders (2) provisioned in the at least one first steering axle (111) to steer the wheels.
In an embodiment, the at least one directional control valve within the valve block (5) may be configured to alter flow path of the fluid from the first circuit (101) to auxiliary circuit (103) or vice versa.
Further, the at least one directional control valve in the valve block (5) may be configured such that under normal operating conditions, the valve block (5) or the at least one directional control valve may be operated to allow passage of fluid from the at least one tandem pump (3) of the first circuit (101). In an embodiment, the at least one directional control valves may be configured to detect non-operating condition of the first circuit (101), which may be due to failure of the components or any other scenario where the steering of the wheels in the at least one first steering axle (111) may not be assisted by hydraulic force. In an embodiment, the at least one directional control valve may be a spring loaded valve and may be biased to close the first circuit (101) and upon the fluid from the first circuit (101) having flow rate more than the predefined flow rate, the at least one directional control valve may be configured to allow passage of the fluid from the first circuit (101) and block passage of fluid from the auxiliary circuit (103) through the valve block (5). Further, upon non-operating condition of the first circuit (101) or the flow rate of the fluid in the first circuit (101) being less than the predefined flow rate, the at least one directional control valve may be configured to operate and block the path of the first circuit (101) and thereby receive fluid from the auxiliary circuit (103), that is, the valve block (5) may be actuated to channelize fluid from the at least one auxiliary pump (9) into the at least one first steering axle (111). This

way the auxiliary circuit (103) provides a failsafe or a backup operation of the steering system (100) such that a user or a driver may steer the vehicle without additional efforts in case of the non-operating condition of the first circuit (101).
In an embodiment, the valve block (5) may include a third sensor [not shown] which may be configured to detect operation of the directional control valve and may be configured to intimate the user or the driver of the non-operating condition of the first circuit (101) by an indication unit which may alert the driver or the user to fix the issue.
In an embodiment, the fluid in the steering system (100) may be a hydraulic fluid. The fluid may be channelized through the steering system (100) through plurality of connecting lines which may be including but not limited to pipes, hoses, tubes and the like.
In an embodiment, the steering system (100) may operate with pneumatic fluid and pneumatic cylinders.
In an embodiment, the vehicle may include a minimum of one first steering axle (111) and a may include two or more first steering axles (111) based on requirement. Further, the vehicle may include a minimum of one second steering axle (112) and a may include two or more second steering axles (112).
In an embodiment, at least one filter (11) may be provisioned in the first circuit (101), the second circuit (102) and the auxiliary circuit (103) which may be configured to filter (11) the fluid returning back into the reservoirs.
In an embodiment, the at least one first sensor and the at least one second sensor may be including but not limited to a transducer or any other device capable of measuring the steering angle.
In an embodiment, the first circuit (101) and the auxiliary circuit (103) may include a control valve to control flow of fluid.
Referring now to Fig. 4 which is an exemplary embodiment of the present disclosure illustrating a flow chart of a method for steering the multi axle vehicle.

The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein.
At block 401, the method may include, operating the at least one tandem pump (3) in the first circuit (101) and channelize the fluid through the valve block (5) to steer the at least one first steering axle (111) of the vehicle. Further, at block 402, the control unit (CU) may be configured to receive the steering angle of the at least one first steering axle (111) from at least one first sensors. Additionally, the control unit (CU) may be also be configured to determine the speed of the vehicle [as seen in block 403] and may be configured to compare the speed of the vehicle with the threshold speed [as seen block 404].
Furthermore, at block 405, the control unit (CU) may be configured to actuate the transfer manifold (7) that may be defined in the second circuit (102) upon detecting the speed of the vehicle to be less than the threshold speed. The transfer manifold (7) upon actuation may be configured to channelize the fluid into the at least one second steering axle (112). Additionally, the control unit (CU) may be configured to regulate the flow of fluid in the second circuit (102) by controlling the transfer manifold (7) to steer the wheels of the at least one second steering axle (112) corresponding to the steering angle received from the at least one first sensor in the at least one first steering axle (111) [as seen block 406].
It should be noted that in an exemplary embodiment, as seen in the Figs. 1-4 the construction, profile, arrangement, layout, connections and method should not be construed as a limitation as the system (100) may include any other type of construction, profile, arrangement, layout, connection and may work with other method or any other combinations for steering the vehicle.
In an embodiment, the steering system (100) is simple in construction which results in low-cost manufacturing and easy maintenance.
In an embodiment, the steering system (100) does not have direct mechanical link between the at least one front steering axle and the at least one second steering axle (112) which reduces the

number of parts. Further, due to the reduction of mechanical parts and utilization of electro-hydraulic circuits the system (100) is less prone to mechanical wear and less failure.
In an embodiment, the steering system (100) provides rear axle steering without reducing the stability of the vehicle at high speeds. The control unit (CU) ensures that the steering system (100) may be capable of operating without any intervention from the driver or the user and provides seamless transition during operation of the at least one second steering axle (112).
In an embodiment, the auxiliary circuit (103) in the steering system (100) provides a fail-safe option which enables the steering system (100) to operate even when the first circuit (101) fails, thereby enabling the driver or the user to maneuver the vehicle without additional effort.
It should be imperative that the construction and configuration of the steering system and any other elements or components described in the above detailed description should not be considered as a limitation with respect to the figures. Rather, variation to such structural configuration of the elements or components should be considered within the scope of the detailed description.
Equivalents:
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such

phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

Referral Numerals:

Reference Number Description
100 System
101 First circuit
102 Second circuit
103 Auxiliary circuit
111 First steering axle
112 Second steering axle
1 Steering gear unit
2 Hydraulic cylinder
3 Tandem pump
4 First reservoir
5 Valve block
6 Second reservoir
7 Transfer manifold
8 Flow control valve
9 Auxiliary pump
10 Auxiliary reservoir
11 Filter
12 Instrument cluster
CU Control unit

We Claim:
1. A steering system (100) for a multi axle vehicle, the steering system (100) comprising:
a first circuit (101) comprising:
at least one tandem pump (3) configured to receive a fluid, wherein the at least one tandem pump (3) delivers pressurized fluid at a predefined flow rate;
a first reservoir (4) fluidly connected to the at least one tandem pump (3), wherein the first reservoir (4) is adapted to store the fluid;
a valve block (5) fluidly coupled to the at least one tandem pump (3) and the first reservoir (4), the valve block (5) is configured to selectively channelize the fluid to at least one first steering axle (111);
a second circuit (102) comprising:
the at least one tandem pump (3) configured to receive the fluid, wherein the at least one tandem pump (3) delivers pressurized fluid at the predefined flow rate;
a second reservoir (6) fluidly connected to the at least one tandem pump (3), wherein the second reservoir (6) is adapted to store the fluid;
a transfer manifold (7) fluidly coupled to the at least one tandem pump (3) and the second reservoir (6), the transfer manifold (7) is configured to selectively channelize fluid to at least one second steering axle (112); and
a control unit (CU) communicatively coupled to the first circuit (101) and the second circuit (102), wherein the control unit (CU) is configured to selectively operate the at least one second steering axle (112) based on vehicle speed and operation of the at least one first steering axle (111).
2. The steering system (100) as claimed in claim 1, wherein the at least one tandem pump (3)
comprises:
a primary pump fluidly connected between the first reservoir (4) and the valve block (5), configured to supply pressurized fluid to the valve block (5); and

a secondary pump connected between the second reservoir (6) and the transfer manifold (7), configured to supply pressurized fluid to the transfer manifold (7).
3. The steering system (100) as claimed in claim 1, wherein the at least one tandem pump (3) is driven by a prime mover of the vehicle.
4. The steering system (100) as claimed in claim 1, wherein the at least one first steering axle (111) comprises a steering gear unit (1) and one or more hydraulic cylinders (2) for steering wheels of the multi axle vehicle.
5. The steering system (100) as claimed in claim 1, wherein the at least one first steering axle (111) comprises at least one first sensor to determine a steering angle of the at least one first steering axle (111).
6. The steering system (100) as claimed in claim 1, wherein the second circuit (102) comprises a flow control valve (8) to control flow of the fluid from the at least one tandem pump (3) to the transfer manifold (7).
7. The steering system (100) as claimed in claim 1, wherein the at least one second steering axle (112) comprises one or more hydraulic cylinders (2), configured to selectively steer the wheels connected to the at least one second steering axle (112).
8. The steering system (100) as claimed in claim 1, wherein the at least one second steering axle (112) comprises at least one second sensor to determine a steering angle of the at least one second steering axle (112).
9. A steering system (100) for a multi axle vehicle, the steering system (100) comprising:
a first circuit (101) comprising:
at least one tandem pump (3) configured to receive a fluid, wherein the at least one tandem pump (3) delivers pressurized fluid at a predefined flow rate;
a first reservoir (4) fluidly connected to the at least one tandem pump (3), wherein the first reservoir (4) is adapted to store the fluid;

a valve block (5) fluidly coupled to the at least one tandem pump (3) and the first reservoir (4), the valve block (5) is configured to selectively channelize the fluid to at least one first steering axle (111);
an auxiliary circuit (103) comprising:
at least one auxiliary pump (9) configured to receive the fluid, wherein the at least one auxiliary pump (9) delivers pressurized fluid at the predefined flow rate; an auxiliary reservoir (10) fluidly connected to the at least one auxiliary pump (9), wherein the auxiliary reservoir (10) is adapted to store the fluid;
wherein the valve block (5) is fluidly coupled to the at least one auxiliary
pump (9) and the auxiliary reservoir (10) and is configured to selectively channelize
fluid to at least one first steering axle (111) of the multi axle vehicle; and
at least one directional control valve provisioned in the valve block (5) and is
configured to selectively channelize the fluid from the auxiliary circuit (103) into the at
least one first steering axle (111) corresponding to non-operating condition of the first
circuit (101).
10. A method for steering a multi axle vehicle, the method comprising:
operating at least one tandem pump (3) in a first circuit (101) to steer the at least one first steering axle (111) of the multi axle vehicle;
receiving, by a control unit (CU), a steering angle of the at least one first steering axle (111) from at least one first sensors;
determining, by the control unit (CU), speed of the multi axle vehicle;
comparing, by the control unit (CU), speed of the multi axle vehicle with a threshold speed;
actuating, by the control unit (CU), a transfer manifold (7) defined in a second circuit (102) on determination of the speed of the multi axle vehicle being less than the threshold speed; and

regulating, by the control unit (CU), flow of fluid in the second circuit (102) based on steering angle of the at least one first steering axle (111) to steer the at least one second steering axle (112) of the multi axle vehicle.