Vehicle Steering System and Vehicle Steering Control Method

Abstract

The present invention relates to the technical field of vehicles, and discloses a vehicle steering system and a vehicle steering control method. The vehicle steering system includes a hydraulic steering gear, a dual-winding assist motor, and a hydraulic redundant assist unit. When the switching valve is in the first working state, the first assist oil pump provides high-pressure oil for the hydraulic steering gear, the second assist oil pump idles, and the dual-winding assist motor provides a first assist torque to the hydraulic steering gear. When the first assist oil pump fails, the switching valve can be switched from the first working state to the second working state through flow sensing. When the switching valve is in the second working state, the second assist oil pump provides high-pressure oil for the hydraulic steering gear, and the dual-winding assist motor provides a second assist torque to the hydraulic steering gear. The present invention can meet the requirements of heavy commercial vehicles for high steering safety under special working conditions. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly to a vehicle steering system and a vehicle steering control method. Background Art

[0002] With the maturity of intelligent driving technology, more and more vehicles are equipped with an electronically controlled hydraulic power steering system. For conventional passenger cars and light trucks, a single electric power steering system can provide sufficient steering assistance for steering operations. For heavy commercial vehicles with high requirements for steering assistance, a single electric power steering system cannot meet the steering assistance requirements, and a hydraulic power steering system must be configured. Among them, the hydraulic power is the main steering assistance, and the electric power steering system provides supplementary steering assistance for steering operations, and can improve the driver's hand force and realize intelligent driving.

[0003] Currently, heavy commercial vehicles mainly use a hydraulic power steering system. After the hydraulic failure occurs, the vehicle cannot steer normally, which has a large potential safety hazard and cannot meet the high-safety steering requirements. Summary of the Invention

[0004] Based on the above problems, the purpose of the present invention is to provide a vehicle steering system and a vehicle steering control method, which can meet the large steering torque requirements of the vehicle, ensure the high safety of vehicle steering, meet the high-safety steering requirements of heavy commercial vehicles under special working conditions, and when the main hydraulic power assistance fails or the electric power assistance fails, the vehicle can still perform normal steering operations.

[0005] To achieve the above purpose, the following technical solutions are provided:

[0006] In a first aspect, the present invention provides a vehicle steering system, including:

[0007] A hydraulic steering gear for driving the vehicle to steer;

[0008] A dual-winding assist motor for providing a first assist torque or a second assist torque to the hydraulic steering gear, and the second assist torque is greater than the first assist torque;

[0009] Hydraulic redundant boost unit, including an oil tank, a first boost oil pump, a second boost oil pump and a switching valve. The oil tank has a first oil chamber and a second oil chamber. The first oil chamber is used to supply oil to the first boost oil pump, and the second oil chamber is used to supply oil to the second boost oil pump. The first boost oil pump and the second boost oil pump are respectively connected to the hydraulic steering gear through the switching valve. The switching valve has a first working state and a second working state. When the switching valve is in the first working state, the first boost oil pump supplies high-pressure oil to the hydraulic steering gear, and the second boost oil pump idles. The dual-winding boost motor supplies the first boost torque to the hydraulic steering gear. When the first boost oil pump fails, the switching valve can be switched from the first working state to the second working state through flow induction. When the switching valve is in the second working state, the second boost oil pump supplies high-pressure oil to the hydraulic steering gear, and the dual-winding boost motor supplies the second boost torque to the hydraulic steering gear.

[0010] As an alternative to the vehicle steering system provided by the present invention, an intermediate partition is provided in the oil tank. The intermediate partition divides the inner cavity of the oil tank into the first oil chamber and the second oil chamber. A communication port is provided on the intermediate partition, and the first oil chamber is communicated with the second oil chamber through the communication port.

[0011] As an alternative to the vehicle steering system provided by the present invention, a first oil inlet communicated with the first oil chamber is provided on the oil tank, and a third oil inlet is provided on the first boost oil pump. The first oil inlet is communicated with the third oil inlet through a first oil inlet pipe.

[0012] As an alternative to the vehicle steering system provided by the present invention, a first high-pressure oil port is provided on the first boost oil pump, and a first high-pressure oil inlet is provided on the switching valve. The first high-pressure oil port is communicated with the first high-pressure oil inlet through a first high-pressure oil pipe.

[0013] As an alternative to the vehicle steering system provided by the present invention, a second oil inlet communicated with the second oil chamber is provided on the oil tank, and a fourth oil inlet is provided on the second boost oil pump. The second oil inlet is communicated with the fourth oil inlet through a second oil inlet pipe.

[0014] As an alternative to the vehicle steering system provided by the present invention, a second high-pressure oil port is provided on the second boost oil pump, and a second high-pressure oil inlet is provided on the switching valve. The second high-pressure oil port is communicated with the second high-pressure oil inlet through a second high-pressure oil pipe.

[0015] As an alternative to the vehicle steering system provided by the present invention, a third oil return port is provided on the switching valve, a second oil return port communicating with the second oil chamber is provided on the oil tank, and the third oil return port is communicated with the second oil return port through a first oil return pipe.

[0016] As an alternative to the vehicle steering system provided by the present invention, a high-pressure oil outlet is provided on the switching valve, a third high-pressure oil port is provided on the hydraulic steering gear, and the high-pressure oil outlet is communicated with the third high-pressure oil port through a third high-pressure oil pipe.

[0017] As an alternative to the vehicle steering system provided by the present invention, a fourth oil return port is provided on the hydraulic steering gear, a first oil return port communicating with the first oil chamber is provided on the oil tank, and the fourth oil return port is communicated with the first oil return port through a second oil return pipe.

[0018] In a second aspect, the present invention further provides a vehicle steering control method, which adopts the above vehicle steering system. The vehicle steering control method includes:

[0019] When the first boost oil pump is working normally, the switching valve is in the first working state. The first boost oil pump provides high-pressure oil fluid for the hydraulic steering gear, the second boost oil pump idles, and the dual-winding boost motor provides a first boost torque for the hydraulic steering gear.

[0020] When the first boost oil pump fails, the switching valve can be switched from the first working state to the second working state through flow sensing. When the switching valve is in the second working state, the second boost oil pump provides high-pressure oil fluid for the hydraulic steering gear, and the dual-winding boost motor provides a second boost torque for the hydraulic steering gear.

[0021] The beneficial effects of the present invention are:

[0022] The vehicle steering system provided by the present invention drives vehicle steering through a hydraulic steering gear. The dual-winding assist motor provides electric assist with a dual redundancy mechanism for vehicle steering, and the hydraulic redundancy assist unit provides hydraulic assist with a dual redundancy mechanism for vehicle steering, thereby meeting the high safety requirements for steering under special working conditions of heavy commercial vehicles. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations; when the first assist oil pump is working properly, the switching valve is in the first working state, the first assist oil pump provides high-pressure oil for the hydraulic steering gear, the second assist oil pump idles, and the dual-winding assist motor provides a first assist torque to the hydraulic steering gear. The dual-winding assist motor provides functions such as vehicle-following assist and active return to improve driving comfort; when the first assist oil pump fails, the switching valve can switch from the first working state to the second working state through flow sensing. When the switching valve is in the second working state, the second assist oil pump provides high-pressure oil for the hydraulic steering gear, and the dual-winding assist motor provides a second assist torque to the hydraulic steering gear to meet the requirement for a larger steering torque and ensure the high safety of vehicle steering.

[0023] The vehicle steering control method provided by the present invention drives vehicle steering through a hydraulic steering gear. The dual-winding assist motor provides electric assist with a dual redundancy mechanism for vehicle steering, and the hydraulic redundancy assist unit provides hydraulic assist with a dual redundancy mechanism for vehicle steering, thereby meeting the high safety requirements for steering under special working conditions of heavy commercial vehicles. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations; when the first assist oil pump is working properly, the switching valve is in the first working state, the first assist oil pump provides high-pressure oil for the hydraulic steering gear, the second assist oil pump idles, and the dual-winding assist motor provides a first assist torque to the hydraulic steering gear. The dual-winding assist motor provides functions such as vehicle-following assist and active return to improve driving comfort; when the first assist oil pump fails, the switching valve can switch from the first working state to the second working state through flow sensing. When the switching valve is in the second working state, the second assist oil pump provides high-pressure oil for the hydraulic steering gear, and the dual-winding assist motor provides a second assist torque to the hydraulic steering gear to meet the requirement for a larger steering torque and ensure the high safety of vehicle steering. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative efforts.

[0025] Figure 1 It is a schematic structural diagram of the vehicle steering system provided by the specific embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the working principle of the vehicle steering system provided by the specific embodiment of the present invention when the first power steering pump is working properly;

[0027] Figure 3 It is a schematic diagram of the working principle of the vehicle steering system provided by the specific embodiment of the present invention when the first power steering pump fails.

[0028] In the figure:

[0029] 11. Oil tank; 111. First oil chamber; 112. Second oil chamber; 113. Intermediate partition; 1131. Communication port; 1111. First oil inlet; 1112. First oil return port; 1121. Second oil inlet; 1122. Second oil return port; 12. First oil inlet pipe; 13. First power steering pump; 131. Third oil inlet; 132. First high-pressure oil port; 133. Power take-off gear; 14. First high-pressure oil pipe; 15. Switching valve; 151. First high-pressure oil inlet; 152. High-pressure oil outlet; 153. Second high-pressure oil inlet; 154. Third oil return port; 155. Working state monitoring module; 16. Second oil inlet pipe; 17. Second power steering pump; 171. Fourth oil inlet; 172. Second high-pressure oil port; 173. Power take-off shaft; 18. Second high-pressure oil pipe; 19. First oil return pipe; 20. Third high-pressure oil pipe; 21. Hydraulic steering gear; 211. Third high-pressure oil port; 212. Fourth oil return port; 213. Input shaft; 22. Dual-winding assist motor; 23. Second oil return pipe. Specific Embodiment

[0030] To make the technical problems solved by the present invention, the technical solutions adopted and the achieved technical effects clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0032] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] As Figures 1 to 3 shown, this embodiment provides a vehicle steering system. The vehicle steering system includes a hydraulic steering gear 21, a dual-winding assist motor 22, and a hydraulic redundant assist unit. The hydraulic steering gear 21 is used to drive the vehicle to steer. The dual-winding assist motor 22 is used to provide a first assist torque or a second assist torque to the hydraulic steering gear 21, and the second assist torque is greater than the first assist torque. The hydraulic redundant assist unit includes an oil tank 11, a first assist oil pump 13, a second assist oil pump 17, and a switching valve 15. The oil tank 11 has a first oil chamber 111 and a second oil chamber 112. The first oil chamber 111 is used to supply oil to the first assist oil pump 13, and the second oil chamber 112 is used to supply oil to the second assist oil pump 17. The first assist oil pump 13 and the second assist oil pump 17 are respectively connected to the hydraulic steering gear 21 through the switching valve 15. The switching valve 15 has a first working state and a second working state. When the switching valve 15 is in the first working state, the first assist oil pump 13 supplies high-pressure oil to the hydraulic steering gear 21, and the second assist oil pump 17 idles. The dual-winding assist motor 22 provides a first assist torque to the hydraulic steering gear 21. When the first assist oil pump 13 fails, the switching valve 15 can be switched from the first working state to the second working state through flow sensing. When the switching valve 15 is in the second working state, the second assist oil pump 17 supplies high-pressure oil to the hydraulic steering gear 21, and the dual-winding assist motor 22 provides a second assist torque to the hydraulic steering gear 21.

[0034] The vehicle steering is driven by a hydraulic steering gear 21. The dual-winding assist motor 22 provides electric assist with a dual-redundancy mechanism for vehicle steering, and the hydraulic redundant assist unit provides hydraulic assist with a dual-redundancy mechanism for vehicle steering, thus meeting the high safety requirements for steering under special working conditions of heavy commercial vehicles. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations; when the first assist oil pump 13 is working properly, the switching valve 15 is in the first working state. The first assist oil pump 13 provides high-pressure oil to the hydraulic steering gear 21, and the second assist oil pump 17 idles. The dual-winding assist motor 22 provides a first assist torque to the hydraulic steering gear 21. The dual-winding assist motor 22 provides functions such as vehicle-following assist and active return, improving driving comfort; when the first assist oil pump 13 fails, the switching valve 15 can be switched from the first working state to the second working state through flow sensing. When the switching valve 15 is in the second working state, the second assist oil pump 17 provides high-pressure oil to the hydraulic steering gear 21, and the dual-winding assist motor 22 provides a second assist torque to the hydraulic steering gear 21, meeting the requirement for a larger steering torque and ensuring high safety of vehicle steering.

[0035] It should be noted that the hydraulic steering gear 21 is used for the main steering assist of the vehicle. An input shaft 213 and an output shaft are provided on the hydraulic steering gear 21. The input shaft 213 is connected to the steering wheel, and the output shaft is connected to the wheels. The dual-winding assist motor 22 is integrated on the hydraulic steering gear 21, and the torque of the dual-winding assist motor 22 acts on the input shaft 213 of the hydraulic steering gear 21. A power take-off gear 133 is provided on the first assist oil pump 13, and the power take-off gear 133 of the first assist oil pump 13 is connected to the power take-off interface of the engine, which is the power source of the vehicle's main hydraulic assist. A power take-off shaft 173 is provided on the second assist oil pump 17, and the power source of the second assist oil pump 17 can be a mechanical power take-off port or electric assist. The hydraulic steering gear 21 can be a recirculating ball and sector shaft type or a rack and pinion type. The power supply interface of the dual-winding assist motor 22 is connected to the vehicle battery, and the CAN communication interface of the dual-winding assist motor 22 is connected to the vehicle's CAN network. When the first assist oil pump 13 fails, the working state monitoring module 155 of the switching valve 15 sends a fault failure signal to the vehicle, and realizes signal interaction with the dual-winding assist motor 22 through the CAN network, enabling the dual-winding assist motor 22 to provide a larger steering assist and assisting the second assist oil pump 17 to jointly provide steering assist for the vehicle, meeting the requirement for a larger steering torque and ensuring high safety of vehicle steering.

[0036] Optionally, an intermediate partition 113 is provided inside the oil tank 11. The intermediate partition 113 divides the inner cavity of the oil tank 11 into a first oil chamber 111 and a second oil chamber 112. A communication port 1131 is provided on the intermediate partition 113, and the first oil chamber 111 communicates with the second oil chamber 112 through the communication port 1131. Under the action of the communication port 1131, the first oil chamber 111 and the second oil chamber 112 communicate with each other at a certain height in the form of a communicating vessel, avoiding uneven oil in the first oil chamber 111 and the second oil chamber 112.

[0037] To facilitate the supply of oil from the first oil chamber 111 to the first boost oil pump 13, optionally, a first oil inlet 1111 communicating with the first oil chamber 111 is provided on the oil tank 11, and a third oil inlet 131 is provided on the first boost oil pump 13. The first oil inlet 1111 is connected to the third oil inlet 131 through a first oil pipe 12.

[0038] To facilitate the supply of high-pressure oil from the first boost oil pump 13 to the switching valve 15, optionally, a first high-pressure oil port 132 is provided on the first boost oil pump 13, and a first high-pressure oil inlet 151 is provided on the switching valve 15. The first high-pressure oil port 132 is connected to the first high-pressure oil inlet 151 through a first high-pressure oil pipe 14.

[0039] To facilitate the supply of oil from the second oil chamber 112 to the second boost oil pump 17, optionally, a second oil inlet 1121 communicating with the second oil chamber 112 is provided on the oil tank 11, and a fourth oil inlet 171 is provided on the second boost oil pump 17. The second oil inlet 1121 is connected to the fourth oil inlet 171 through a second oil pipe 16.

[0040] To facilitate the supply of high-pressure oil from the second boost oil pump 17 to the switching valve 15, optionally, a second high-pressure oil port 172 is provided on the second boost oil pump 17, and a second high-pressure oil inlet 153 is provided on the switching valve 15. The second high-pressure oil port 172 is connected to the second high-pressure oil inlet 153 through a second high-pressure oil pipe 18.

[0041] To facilitate the return of oil when the second boost oil pump 17 idles, optionally, a third oil return port 154 is provided on the switching valve 15, and a second oil return port 1122 communicating with the second oil chamber 112 is provided on the oil tank 11. The third oil return port 154 is connected to the second oil return port 1122 through a first oil return pipe 19.

[0042] To facilitate the supply of high-pressure oil from the switching valve 15 to the hydraulic steering gear 21, optionally, a high-pressure oil outlet 152 is provided on the switching valve 15, and a third high-pressure oil port 211 is provided on the hydraulic steering gear 21. The high-pressure oil outlet 152 is connected to the third high-pressure oil port 211 through a third high-pressure oil pipe 20.

[0043] For convenient oil return, optionally, a fourth oil return port 212 is provided on the hydraulic steering gear 21, and a first oil return port 1112 communicating with the first oil chamber 111 is provided on the oil tank 11. The fourth oil return port 212 is communicated with the first oil return port 1112 through a second oil return pipe 23.

[0044] As Figure 1 and Figure 2 shown, when the first hydraulic power assist works normally, the first hydraulic power assist oil flows from the first oil inlet 1111 through the first oil pipe 12 into the third oil inlet 131, becomes high-pressure oil after passing through the first power assist oil pump 13, flows out from the first high-pressure oil port 132, flows through the first high-pressure oil pipe 14 into the first high-pressure oil inlet 151, then passes through the high-pressure oil outlet 152, and flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20 to drive the vehicle to steer normally. The oil flows back from the fourth oil return port 212 through the second oil return pipe 23 to the first oil return port 1112; the second hydraulic power assist oil flows from the second oil inlet 1121 through the second oil pipe 16 into the fourth oil inlet 171, passes through the second power assist oil pump 17, flows out from the second high-pressure oil port 172, flows through the second high-pressure oil pipe 18 into the second high-pressure oil inlet 153, and then flows back from the third oil return port 154 through the first oil return pipe 19 to the second oil return port 1122 for idling operation; at this time, the dual-winding assist motor 22 plays an auxiliary role in intelligent driving and does not participate in the output of a large steering force.

[0045] As Figure 1 and Figure 3As shown, when the first hydraulic power assist fails and the flow rate drops to the set value of the switching valve 15, the second hydraulic power assist is switched to drive the hydraulic steering gear 21 at this time, providing the main power assist for vehicle steering. At the same time, the working status monitoring module 155 transmits the first steering power assist failure information to the vehicle CAN, and then the vehicle increases the torque output by controlling the dual-winding assist motor 22 through the CAN to meet the demand for a larger steering force of the vehicle. At this time, the oil of the first hydraulic power assist flows from the first oil inlet 1111 through the first oil pipe 12 into the third oil inlet 131, passes through the first power assist oil pump 13, flows out from the first high-pressure oil port 132, flows into the first high-pressure oil inlet 151 through the first high-pressure oil pipe 14, and then flows out from the high-pressure oil outlet 152 through the overflow valve inside the switching valve 15, flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20, and the oil flows back to the first oil return port 1112 through the second oil return pipe 23 from the fourth oil return port 212; the oil of the second hydraulic power assist flows from the second oil inlet 1121 through the second oil pipe 16 into the fourth oil inlet 171, passes through the second power assist oil pump 17, flows out from the second high-pressure oil port 172, flows into the second high-pressure oil inlet 153 through the second high-pressure oil pipe 18, and then flows out from the high-pressure oil outlet 152, flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20, and the oil flows back to the first oil return port 1112 through the second oil return pipe 23 from the fourth oil return port 212. At this time, the oil in the second oil chamber 112 flows into the first oil chamber 111, and then a certain amount of oil flows into the oil tank 11 through the communication port 1131 on the intermediate partition 113 to maintain the oil balance and avoid the lack of oil in the second oil chamber 112.

[0046] It can be understood that the dual-winding assist motor 22 corresponds to two control units and related components, has a redundant auxiliary electric power assist function, and the two communicate with each other to judge whether the functions of each module are normal. Under normal circumstances, the first control module motor provides steering power assist. When one of the windings fails, the other winding intervenes to provide steering electric power assist; when the first hydraulic power assist is normal, the dual-winding assist motor 22 only provides a small amount of power assist for intelligent driving and improving the hand force; when it is detected that the first hydraulic power assist of the system fails, the dual-winding assist motor 22 provides a large amount of steering power assist to cooperate with the second hydraulic power assist to meet the safety requirements for a larger steering force of heavy commercial vehicles.

[0047] The vehicle steering system provided in this embodiment drives vehicle steering through a hydraulic steering gear 21. A dual-winding assist motor 22 provides electric assist with a dual-redundancy mechanism for vehicle steering, and a hydraulic redundant assist unit provides hydraulic assist with a dual-redundancy mechanism for vehicle steering, thereby meeting the demand for high steering safety of heavy commercial vehicles under special working conditions. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations. When the first assist oil pump 13 is working normally, the switching valve 15 is in the first working state. The first assist oil pump 13 supplies high-pressure oil to the hydraulic steering gear 21, the second assist oil pump 17 idles, and the dual-winding assist motor 22 provides a first assist torque to the hydraulic steering gear 21. The dual-winding assist motor 22 provides functions such as vehicle following assist and active return, improving driving comfort. When the first assist oil pump 13 fails, the switching valve 15 can switch from the first working state to the second working state through flow sensing. When the switching valve 15 is in the second working state, the second assist oil pump 17 supplies high-pressure oil to the hydraulic steering gear 21, and the dual-winding assist motor 22 provides a second assist torque to the hydraulic steering gear 21, meeting the demand for a larger steering torque and ensuring high steering safety of the vehicle.

[0048] This embodiment also provides a vehicle steering control method, which adopts the above vehicle steering system. The vehicle steering control method includes:

[0049] When the first assist oil pump 13 is working normally, the switching valve 15 is in the first working state. The first assist oil pump 13 supplies high-pressure oil to the hydraulic steering gear 21, the second assist oil pump 17 idles, and the dual-winding assist motor 22 provides a first assist torque to the hydraulic steering gear 21.

[0050] When the first assist oil pump 13 fails, the switching valve 15 can switch from the first working state to the second working state through flow sensing. When the switching valve 15 is in the second working state, the second assist oil pump 17 supplies high-pressure oil to the hydraulic steering gear 21, and the dual-winding assist motor 22 provides a second assist torque to the hydraulic steering gear 21.

[0051] Specifically, as Figure 1 and Figure 2As shown in the figure, when the first hydraulic power assist works normally, the first hydraulic power assist fluid flows from the first oil inlet 1111 through the first oil pipe 12 into the third oil inlet 131, becomes high-pressure oil after passing through the first power assist oil pump 13, flows out from the first high-pressure oil port 132, flows through the first high-pressure oil pipe 14 into the first high-pressure oil inlet 151, then passes through the high-pressure oil outlet 152, and flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20 to drive the vehicle to turn normally. The fluid returns from the fourth oil return port 212 to the first oil return port 1112 through the second oil return pipe 23; the second hydraulic power assist fluid flows from the second oil inlet 1121 through the second oil pipe 16 into the fourth oil inlet 171, passes through the second power assist oil pump 17, flows out from the second high-pressure oil port 172, flows through the second high-pressure oil pipe 18 into the second high-pressure oil inlet 153, then from the third oil return port 154, and returns to the second oil return port 1122 through the first oil return pipe 19 for idling operation; at this time, the dual-winding assist motor 22 plays an auxiliary role in intelligent driving and does not participate in the output of a large steering force.

[0052] As Figure 1 and Figure 3 shown in the figure, when the first hydraulic power assist fails and the flow rate drops to the set value of the switching valve 15, at this time, it switches to the second hydraulic power assist to drive the hydraulic steering gear 21 to provide the main assist for vehicle steering. At the same time, the working state monitoring module 155 transmits the first steering assist failure information to the vehicle CAN, and then the vehicle controls the dual-winding assist motor 22 to increase the torque output through the CAN to meet the demand for a large vehicle steering force. At this time, the first hydraulic power assist fluid flows from the first oil inlet 1111 through the first oil pipe 12 into the third oil inlet 131, passes through the first power assist oil pump 13, flows out from the first high-pressure oil port 132, flows through the first high-pressure oil pipe 14 into the first high-pressure oil inlet 151, then through the overflow valve inside the switching valve 15 from the high-pressure oil outlet 152, and flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20. The fluid returns from the fourth oil return port 212 to the first oil return port 1112 through the second oil return pipe 23; the second hydraulic power assist fluid flows from the second oil inlet 1121 through the second oil pipe 16 into the fourth oil inlet 171, passes through the second power assist oil pump 17, flows out from the second high-pressure oil port 172, flows through the second high-pressure oil pipe 18 into the second high-pressure oil inlet 153, then the high-pressure oil outlet 152, and flows into the third high-pressure oil port 211 through the third high-pressure oil pipe 20. The fluid returns from the fourth oil return port 212 to the first oil return port 1112 through the second oil return pipe 23. At this time, the fluid in the second oil chamber 112 flows into the first oil chamber 111, and then a certain amount of fluid flows into the oil tank 11 through the connection port 1131 on the intermediate partition 113 to maintain the fluid balance and avoid the lack of oil in the second oil chamber 112.

[0053] The vehicle steering control method provided in this embodiment drives vehicle steering through a hydraulic steering gear 21. A dual-winding assist motor 22 provides electric assist with a dual-redundancy mechanism for vehicle steering, and a hydraulic redundant assist unit provides hydraulic assist with a dual-redundancy mechanism for vehicle steering, thereby meeting the demand for high steering safety of heavy commercial vehicles under special working conditions. When the main hydraulic assist fails or the electric assist fails, the vehicle can still perform normal steering operations; when the first assist oil pump 13 is working properly, the switching valve 15 is in the first working state, the first assist oil pump 13 provides high-pressure oil for the hydraulic steering gear 21, the second assist oil pump 17 idles, and the dual-winding assist motor 22 provides a first assist torque to the hydraulic steering gear 21. The dual-winding assist motor 22 provides functions such as vehicle-following assist and active return-to-center, improving driving comfort; when the first assist oil pump 13 fails, the switching valve 15 can be switched from the first working state to the second working state through flow sensing. When the switching valve 15 is in the second working state, the second assist oil pump 17 provides high-pressure oil for the hydraulic steering gear 21, and the dual-winding assist motor 22 provides a second assist torque to the hydraulic steering gear 21, meeting the demand for a larger steering torque and ensuring high steering safety of the vehicle.

[0054] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments here. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A vehicle steering system, characterized in that, Comprising: A hydraulic steering gear (21) for driving vehicle steering; A dual-winding assist motor (22) for providing a first assist torque or a second assist torque to the hydraulic steering gear (21), the second assist torque being greater than the first assist torque; A hydraulic redundant assist unit, including an oil tank (11), a first assist oil pump (13), a second assist oil pump (17) and a switching valve (15), the oil tank (11) having a first oil chamber (111) and a second oil chamber (112), the first oil chamber (111) for supplying oil to the first assist oil pump (13), the second oil chamber (112) for supplying oil to the second assist oil pump (17), the first assist oil pump (13) and the second assist oil pump (17) being respectively connected to the hydraulic steering gear (21) through the switching valve (15), the switching valve (15) having a first working state and a second working state; when the switching valve (15) is in the first working state, the first assist oil pump (13) supplies high-pressure oil to the hydraulic steering gear (21), the second assist oil pump (17) idles, and the dual-winding assist motor (22) provides the first assist torque to the hydraulic steering gear (21); when the first assist oil pump (13) fails, the switching valve (15) can be switched from the first working state to the second working state by flow sensing; when the switching valve (15) is in the second working state, the second assist oil pump (17) supplies high-pressure oil to the hydraulic steering gear (21), and the dual-winding assist motor (22) provides the second assist torque to the hydraulic steering gear (21); An intermediate partition (113) is provided in the oil tank (11), the intermediate partition (113) divides the inner cavity of the oil tank (11) into the first oil chamber (111) and the second oil chamber (112), a communication port (1131) is provided on the intermediate partition (113), and the first oil chamber (111) is communicated with the second oil chamber (112) through the communication port (1131); A first high-pressure oil port (132) is provided on the first assist oil pump (13), a first high-pressure oil inlet (151) is provided on the switching valve (15), and the first high-pressure oil port (132) is communicated with the first high-pressure oil inlet (151) through a first high-pressure oil pipe (14).

2. The vehicle steering system according to claim 1, characterized in that, A first oil inlet (1111) communicated with the first oil chamber (111) is provided on the oil tank (11), a third oil inlet (131) is provided on the first assist oil pump (13), and the first oil inlet (1111) is communicated with the third oil inlet (131) through a first oil pipe (12).

3. The vehicle steering system according to claim 1, characterized in that, A second oil inlet (1121) communicated with the second oil chamber (112) is provided on the oil tank (11), a fourth oil inlet (171) is provided on the second assist oil pump (17), and the second oil inlet (1121) is communicated with the fourth oil inlet (171) through a second oil pipe (16).

4. The vehicle steering system according to claim 1, characterized in that, A second high-pressure oil port (172) is provided on the second boost oil pump (17), a second high-pressure oil inlet (153) is provided on the switching valve (15), and the second high-pressure oil port (172) is communicated with the second high-pressure oil inlet (153) through a second high-pressure oil pipe (18).

5. The vehicle steering system according to claim 1, characterized in that, A third oil return port (154) is provided on the switching valve (15), a second oil return port (1122) communicated with the second oil chamber (112) is provided on the oil tank (11), and the third oil return port (154) is communicated with the second oil return port (1122) through a first oil return pipe (19).

6. The vehicle steering system according to claim 1, characterized in that, A high-pressure oil outlet (152) is provided on the switching valve (15), a third high-pressure oil port (211) is provided on the hydraulic steering gear (21), and the high-pressure oil outlet (152) is communicated with the third high-pressure oil port (211) through a third high-pressure oil pipe (20).

7. The vehicle steering system according to claim 1, characterized in that, A fourth oil return port (212) is provided on the hydraulic steering gear (21), a first oil return port (1112) communicated with the first oil chamber (111) is provided on the oil tank (11), and the fourth oil return port (212) is communicated with the first oil return port (1112) through a second oil return pipe (23).

8. A vehicle steering control method, characterized in that, Using the vehicle steering system according to any one of claims 1-7, the vehicle steering control method includes: When the first boost oil pump (13) works normally, the switching valve (15) is in a first working state, the first boost oil pump (13) provides high-pressure oil fluid for the hydraulic steering gear (21), the second boost oil pump (17) idles, and the dual-winding boost motor (22) provides a first boost torque for the hydraulic steering gear (21). When the first boost oil pump (13) fails, the switching valve (15) can be switched from the first working state to the second working state by flow induction. When the switching valve (15) is in the second working state, the second boost oil pump (17) provides high-pressure oil fluid for the hydraulic steering gear (21), and the dual-winding boost motor (22) provides a second boost torque for the hydraulic steering gear (21).

Images