Hydraulic steering system, control method of hydraulic steering system and electric equipment

Abstract

The invention discloses a hydraulic steering system, a control method of the hydraulic steering system and electric equipment.The hydraulic steering system comprises a steering actuator, a main loop and an emergency loop, and the steering actuator is used for executing steering action through driving of oil liquid; the main loop takes a driving motor powered by an engine or a power battery as a driving source and is used for pumping oil to the steering actuator in a normal working state; the emergency loop is connected with a drive axle of the vehicle, takes the drive axle as a drive source and is used for pumping oil to the steering actuator when the main loop is in a fault state. According to the hydraulic steering system, hydraulic power can still be continuously provided through the emergency loop when the main loop breaks down, and the emergency loop takes the drive axle as a drive source, so that a vehicle can still keep the steering control capacity when the main loop fails, and the safety and reliability of vehicle steering operation are improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a hydraulic steering system, a control method for the hydraulic steering system, and electrical equipment. Background Technology

[0002] Currently, both traditional and new energy vehicles can employ hydraulic power steering systems. These systems use an engine or electric motor to drive a hydraulic pump, which delivers high-pressure hydraulic fluid to the steering actuators to provide steering assistance. Under normal operating conditions, these systems meet national regulations and practical operational requirements, such as the steering force specifications in GB7258 and the requirement for vehicles with high steering axle loads to be equipped with power steering devices. While traditional energy vehicles use an engine-driven hydraulic pump, new energy vehicles use a battery-powered electric motor to power the hydraulic pump, achieving a similar steering assistance effect.

[0003] However, existing hydraulic power steering systems generally use a single power source. If the engine, motor, or battery fails, or the main hydraulic pump fails, the vehicle will suddenly lose power steering assistance, resulting in a sharp increase in steering wheel effort. This significantly increases the difficulty of steering at high speeds or under heavy loads, posing a serious traffic safety hazard. To address these issues, existing technology employs a dual-source electro-hydraulic power steering solution. This involves adding a motor drive system to the existing hydraulic power steering system. The motor uses a battery as a power source and directly drives the input shaft of the steering actuator to provide power assistance. However, because the energy provided by the battery is relatively small, the power assistance effect is limited, and the risk of electrical failure remains. This makes it impossible to guarantee continuous power steering assistance, easily leading to difficulty in steering and potentially causing traffic accidents. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this invention is to provide a hydraulic steering system that can continue to provide hydraulic assistance through an emergency circuit even in the event of a main circuit failure. The emergency circuit uses the drive axle as its driving source, enabling the vehicle to maintain steering control capability even when the main circuit fails, thereby improving the safety and reliability of vehicle steering operations.

[0005] The second objective of this invention is to provide a control method for a hydraulic steering system.

[0006] The third objective of this invention is to provide an electrical device.

[0007] To achieve the above objectives, a hydraulic steering system according to a first aspect of the present invention includes: a steering actuator for performing steering actions by being driven by hydraulic fluid; a main circuit, wherein the main circuit is driven by a drive motor powered by an engine or a power battery, and is used to pump hydraulic fluid to the steering actuator during normal operation; and an emergency circuit, wherein the emergency circuit is connected to the drive axle of the vehicle and is driven by the drive axle, and is used to pump hydraulic fluid to the steering actuator when the main circuit is in a faulty state.

[0008] According to an embodiment of the hydraulic steering system of the present invention, during normal vehicle operation, the main circuit is driven by a hydraulic pump powered by an engine or power battery to supply oil to the steering actuator, achieving conventional hydraulic power assistance. When the main circuit fails due to engine stall, motor failure, or power battery malfunction, the emergency circuit automatically intervenes. Because the emergency circuit is connected to the vehicle's drive axle, it can directly utilize the rotational kinetic energy transmitted from the wheels to the drive axle during vehicle movement as a drive source. This is used to pump oil to the steering actuator when the main circuit is in a faulty state, so as to continuously provide hydraulic power assistance to the steering actuator in the event of main circuit failure. Since the rotational speed of the drive axle is directly related to the vehicle's driving state, it can maintain continuous rotation even during inertial driving or driving on an incline. Therefore, the power assist output of the emergency circuit changes smoothly with the vehicle speed, and there will be no sudden change in steering force due to a sudden interruption of the power source. At the same time, compared with emergency power assist methods that use low-voltage batteries as a power source, the emergency circuit of this invention does not rely on low-voltage circuit power supply, avoiding the problems of limited low-voltage battery power and complete loss of power assist due to fuse blowout caused by instantaneous overload. This makes the power source of steering assist more continuous and reliable when the vehicle is in motion, so as to effectively ensure the vehicle's steering control ability even in the event of a failure of the main circuit, thereby improving the safety and reliability of vehicle steering operation.

[0009] In some embodiments, the emergency circuit includes an emergency oil pump, which is driven by one or more constantly meshing gear pairs via gears on the drive axle's drive bevel gear shaft.

[0010] In some embodiments, the inlet of the emergency oil pump is connected to the outlet of the oil tank; the hydraulic steering system further includes a reversing valve, which is connected to the return port of the oil tank, the outlet of the emergency oil pump, and the steering actuator via a pipeline. When the reversing valve is in a first position, the outlet of the emergency oil pump is connected to the return port of the oil tank, and when the reversing valve is in a second position, the outlet of the emergency oil pump is connected to the steering actuator.

[0011] In some embodiments, the main circuit includes a main oil pump, the inlet of which is connected to the outlet of the oil tank, the outlet of which is connected to the steering actuator, and the drive end of which is connected to the engine or the drive motor.

[0012] In some embodiments, the main circuit further includes a one-way valve located on an outlet pipe connected to the outlet of the main oil pump, the outlet pipe being connected to the steering actuator. The one-way valve is used to control the unidirectional flow of oil from the outlet of the main oil pump to the steering actuator, and is configured to open to supply fluid to the steering actuator when the main circuit is operating normally.

[0013] In some embodiments, the drive end of the reversing valve is connected between the outlet of the main oil pump and the check valve, and the oil pumped by the main oil pump during normal operation drives the reversing valve to move to the first position.

[0014] To achieve the above objectives, a control method for a hydraulic steering system according to a second aspect of the present invention is used to control the hydraulic steering system described in the above embodiment. The control method includes: when the main circuit of the hydraulic steering system is in normal working condition, the main circuit provides hydraulic fluid to the steering actuator of the hydraulic steering system, and the emergency circuit of the hydraulic steering system does not intervene in steering drive; when the main circuit is in a fault state, the emergency circuit provides hydraulic fluid to the steering actuator of the hydraulic steering system, and the emergency circuit uses the vehicle's drive axle as the drive source.

[0015] According to the control method of the hydraulic steering system of the present invention, when the main circuit is in normal working condition, the emergency circuit is controlled not to intervene in the steering drive, so that the steering actuator is only supplied with oil by the main circuit driven by the drive motor powered by the engine or power battery. This ensures that the hydraulic steering system operates stably in the existing manner under normal working conditions, avoids unnecessary energy consumption or system interference caused by the emergency circuit participating in the work, and ensures the stability and consistency of the steering assist output. When the main circuit fails to supply hydraulic fluid due to engine, motor, or power battery malfunction, the emergency circuit automatically intervenes by switching the steering drive path and uses the vehicle's drive axle as the drive source to supply fluid to the steering actuator. Since the rotation of the drive axle originates from the kinetic energy transmitted by the wheels during vehicle movement, it can continuously output power even when the vehicle is still in a state of inertial driving or on an incline. Therefore, this method achieves seamless switching and continuous supply of steering assist in the event of main circuit failure, avoiding sudden changes in steering force caused by a sudden interruption of the power source. At the same time, it does not rely on the low-voltage battery and its electrical circuit, thus avoiding risks such as low-voltage circuit overload and fuse blowout from the control strategy level. This ensures that the emergency circuit always has a usable power source during vehicle movement, thereby guaranteeing the vehicle's steering control capability even when the main circuit fails, and improving the safety and reliability of steering operation.

[0016] In some embodiments, under normal operating conditions of the main circuit, the check valve in the hydraulic steering system is turned on and drives the directional valve to move to the first position. The emergency oil pump in the emergency circuit pumps oil as the drive axle's drive bevel gear rotates during vehicle operation. The oil pumped by the emergency oil pump is unloaded through the directional valve.

[0017] In some embodiments, under the fault condition of the main circuit, the main oil pump of the main circuit stops working, the driving force of the reversing valve in the emergency circuit disappears, and the reversing valve automatically switches to the second position under the action of spring force. Under the vehicle driving condition, the driving bevel gear of the drive axle drives the emergency oil pump in the emergency circuit through one or more constant mesh gear pairs. The oil pumped by the emergency oil pump is provided to the steering actuator through the reversing valve to perform steering action.

[0018] To achieve the above objectives, the third aspect of the present invention provides an electrical device for implementing the control method of the hydraulic steering system described in the above embodiments, or the electrical device is a vehicle that includes the hydraulic steering system described in the above embodiments and / or implements the control method of the hydraulic steering system described in the above embodiments.

[0019] According to the embodiments of the present invention, by employing the hydraulic steering system and / or the control method of the hydraulic steering system described in the above embodiments, the electrical equipment can still provide hydraulic assistance through the emergency circuit when the main circuit fails, and the emergency circuit uses the drive axle as the drive source, so that the vehicle can still maintain steering control capability when the main circuit fails, thereby improving the safety and reliability of vehicle steering operation.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the main circuit of a hydraulic steering system with an engine as the driving source in normal working condition according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the main circuit of a hydraulic steering system according to an embodiment of the present invention, in which the drive motor is the drive source, when the main circuit is in normal working condition. Figure 3 This is a schematic diagram of a hydraulic steering system according to an embodiment of the present invention when the main circuit driven by the engine is in a fault state. Figure 4 This is a schematic diagram of a hydraulic steering system according to an embodiment of the present invention when the main circuit with the drive motor as the drive source is in a fault state. Figure 5 This is a flowchart of a control method for a hydraulic steering system according to an embodiment of the present invention; Figure 6 This is a block diagram of a vehicle according to an embodiment of the present invention.

[0022] Figure label: 100 vehicles; 1. Hydraulic steering system; 2. Engine; 3. Drive motor; 4. Drive axle; 5. Oil tank; Steering actuator 11; main circuit 12; emergency circuit 13; directional valve 14; Main oil pump 121; check valve 122; emergency oil pump 131; control circuit 141. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0024] The following is for reference. Figures 1-4A hydraulic steering system according to an embodiment of the present invention is described.

[0025] In some embodiments, such as Figure 1 As shown, the hydraulic steering system 1 includes: a steering actuator 11, a main circuit 12, and an emergency circuit 13.

[0026] In some embodiments, the steering actuator 11 can be a hydraulic steering unit, used to perform steering actions by being driven by hydraulic fluid. Specifically, the steering actuator 11 can be used to convert hydraulic energy into mechanical energy to drive the steering mechanism to produce steering displacement. By selectively supplying high-pressure hydraulic fluid to the hydraulic chambers on both sides of the steering actuator 11 and returning low-pressure hydraulic fluid, control over the vehicle's steering direction and steering torque is achieved, thereby reducing the force exerted by the driver on the steering wheel during steering operations and improving the comfort and controllability of steering.

[0027] In some embodiments, the main circuit 12 can be a hydraulic power supply path for providing hydraulic assistance to the steering actuator 11 under normal vehicle operating conditions. The main circuit 12 is driven by a drive motor 3 powered by the engine 2 or a power battery, and pumps hydraulic fluid to the steering actuator 11 under normal operating conditions, thereby achieving continuous hydraulic assistance for vehicle steering. By setting the main circuit 12, the vehicle can stably and continuously receive steering assistance during normal driving, meeting the steering control needs under daily driving conditions.

[0028] In some embodiments, such as Figure 1 As shown, when the main circuit 12 is driven by the engine 2, the main circuit 12 can be applied to the hydraulic steering system 1 of a conventional energy vehicle. For example, the engine 2 drives the oil pump of the main circuit 12 through a belt, gear or coupling, thereby providing the required hydraulic fluid to the steering actuator 11.

[0029] In some embodiments, such as Figure 2 As shown, when the main circuit 12 is driven by the drive motor 3 powered by the power battery, the main circuit 12 can be applied to the hydraulic steering system 1 of new energy vehicles or hybrid vehicles. For example, the power battery supplies power to the drive motor 3, and the drive motor 3 directly or indirectly drives the oil pump of the main circuit 12 to achieve hydraulic power assist output to the steering actuator 11. Through the above settings, the hydraulic steering system 1 of the present invention can be applied to both traditional energy vehicles and new energy vehicles, and has strong platform versatility and adaptability.

[0030] In some embodiments, the emergency circuit 13 may be a backup hydraulic power supply path that replaces the main circuit 12 in providing hydraulic assistance to the steering actuator 11 when the main circuit 12 is unable to supply oil normally due to a failure of the engine 2, motor or power battery.

[0031] In some embodiments, such as Figure 3 As shown, when the main circuit 12, driven by engine 2, is in a fault state, the emergency circuit 13 is connected to the vehicle's drive axle 4 and driven by the drive axle 4. It is used to pump oil to the steering actuator 11 when the main circuit 12 is in a fault state, thereby ensuring that the vehicle still has basic and controllable steering operation capability when the main circuit 12 is in a fault state.

[0032] In some embodiments, such as Figure 4 As shown, when the main circuit 12, which is driven by the drive motor 3 powered by the power battery, is in a fault state, the emergency circuit 13 is connected to the drive axle 4 of the vehicle and uses the drive axle 4 as the drive source. It is used to pump oil to the steering actuator 11 when the main circuit 12 is in a fault state, thereby ensuring that the vehicle still has basic and controllable steering operation capability when the main circuit 12 is in a fault state.

[0033] In some embodiments, the drive axle 4 can be a structural assembly in the vehicle's transmission system that transmits power to the wheels. The emergency circuit 13 is connected to the vehicle's drive axle 4 and uses the drive axle 4 as its drive source, meaning that the oil pump of the emergency circuit 13 is directly driven by the mechanical energy generated by the drive axle 4 during vehicle operation. This makes the power source of the emergency circuit 13 directly related to the vehicle's driving state. Since the rotational speed and output power of the drive axle 4 continuously change with the vehicle speed, the problem of sudden changes in steering force during the switching between the main circuit 12 and the emergency circuit 13 is avoided, improving the driver's handling stability.

[0034] Furthermore, since the emergency circuit 13 can provide hydraulic power without relying on the low-voltage battery and its electrical control circuit 141, it avoids the problem of hydraulic power assist failure of the emergency circuit 13 due to low-voltage circuit overload, fuse blowout or electrical fault. As long as the vehicle is still in motion, the emergency circuit 13 can continuously provide hydraulic power assist without interruption of power assist, thus improving the safety and reliability of vehicle steering operation.

[0035] According to an embodiment of the hydraulic steering system 1 of the present invention, during normal vehicle operation, the main circuit 12 is driven by the drive motor 3 powered by the engine 2 or the power battery to supply oil to the steering actuator 11, thereby achieving conventional hydraulic power assistance. When the main circuit 12 fails due to engine 2 stalling, motor failure, or power battery malfunction, the emergency circuit 13 automatically intervenes. Since the emergency circuit 13 is connected to the vehicle drive axle 4, it can directly utilize the rotational kinetic energy transmitted from the wheels to the drive axle 4 during vehicle operation as a drive source to pump oil to the steering actuator 11 when the main circuit 12 is in a faulty state, so as to continuously provide hydraulic power assistance to the steering actuator 11 in the event of failure of the main circuit 12. Since the rotational speed of the drive axle 4 is directly related to the vehicle's driving state, it can maintain continuous rotation during inertial driving or hill driving. Therefore, the power assist output of the emergency circuit 13 changes smoothly with the vehicle speed, and there will be no sudden change in steering force due to a sudden interruption of the power source. At the same time, compared with the emergency power assist method that uses a low-voltage battery as a power source, the emergency circuit 13 of this invention does not rely on the low-voltage circuit for power supply, avoiding the problems of limited power of the low-voltage battery and complete loss of power assist due to fuse blowout caused by instantaneous overload. This makes the power source of steering assist more continuous and reliable when the vehicle is in motion, so that the vehicle's steering control ability can still be effectively guaranteed in the event of failure of the main circuit 12, thereby improving the safety and reliability of vehicle steering operation.

[0036] In some embodiments, such as Figures 1-4 As shown, the emergency circuit 13 includes an emergency oil pump 131. When driving force is obtained, the emergency oil pump 131 draws in low-pressure oil from the oil tank 5, pressurizes it, and outputs it to the steering actuator 11, providing the steering actuator 11 with the oil pressure and flow required to achieve steering assistance. When the main circuit 12 of the hydraulic steering system 1 is in a faulty state, the emergency oil pump 131, as the core power actuator of the emergency circuit 13, continuously supplies oil to the steering actuator 11, realizing the steering assistance function of the vehicle in abnormal conditions and improving the vehicle's steering safety.

[0037] In some embodiments, the emergency oil pump 131 may be a gear pump, vane pump, piston pump, or other hydraulic pump suitable for mechanical transmission, and its structure and specifications may be selected according to the power assist requirements of the steering system.

[0038] In some embodiments, the emergency oil pump 131 is driven by one or more constantly meshed gear pairs via gears on the drive bevel gear shaft of the drive axle 4. The drive bevel gear shaft can be a drive shaft inside the drive axle 4 used to input power from the drive shaft to the differential; the constantly meshed gear pair drive means that the gear on the input side of the emergency oil pump 131 and the gear on the drive bevel gear shaft are structurally always engaged, rather than being intermittently engaged via a clutch, belt, or electronic control. By using constantly meshed gear pairs, the emergency oil pump 131 can continuously output torque as the drive bevel gear shaft rotates without additional control during vehicle operation.

[0039] In some embodiments, one or more constant mesh gear pairs can be used to achieve speed matching, torque amplification, or transmission direction adjustment, so that the emergency oil pump 131 can obtain suitable drive speed and output capacity under different vehicle speeds or different operating conditions.

[0040] In some embodiments, through the above-described constant mesh gear pair drive method, the emergency oil pump 131 can immediately start working the moment a fault occurs in the main circuit 12, without waiting for the meshing action to be completed, thereby avoiding power steering interruption or sudden change, and improving the response speed and working continuity of the steering system.

[0041] In some embodiments, such as Figures 1-4 As shown, the inlet of the emergency oil pump 131 is connected to the outlet of the oil tank 5. This is to provide a stable and continuous oil source for the emergency oil pump 131, thereby ensuring that the emergency oil pump 131 can reliably draw in oil and establish hydraulic output during operation.

[0042] In some embodiments, the hydraulic steering system 1 further includes a directional control valve 14. The function of the directional control valve 14 is to allow the valve core to switch between different positions based on the force of the high-pressure oil, thereby changing the flow direction of the outlet oil of the emergency oil pump 131, and thus controlling whether the emergency circuit 13 intervenes in the steering actuator 11 to participate in steering assistance.

[0043] In some embodiments, the reversing valve 14 is connected to the return port of the oil tank 5, the outlet of the emergency oil pump 131, and the steering actuator 11 via pipelines.

[0044] In some embodiments, such as Figure 1 and Figure 2As shown, when the reversing valve 14 is in the first position, the outlet of the emergency oil pump 131 is connected to the return port of the oil tank 5. Combined with the connection between the inlet of the emergency oil pump 131 and the outlet of the oil tank 5, a circulation loop can be formed from the outlet of the oil tank 5 through the emergency oil pump 131, and then through the reversing valve 14 back to the return port of the oil tank 5. Therefore, the oil output by the emergency oil pump 131 does not enter the steering actuator 11, but is directly guided back to the oil tank 5 through the reversing valve 14, thereby unloading the emergency oil pump 131. This ensures that the emergency circuit 13 does not participate in the power steering operation when the main circuit 12 is in normal working condition, thus reducing system energy loss and avoiding affecting the normal operation of the main circuit 12.

[0045] In some embodiments, such as Figure 3 and Figure 4 As shown, when the reversing valve 14 is in the second position, the outlet of the emergency oil pump 131 is connected to the steering actuator 11. Combined with the connection between the inlet of the emergency oil pump 131 and the outlet of the oil tank 5, an emergency circuit 13 can be formed, running from the outlet of the oil tank 5 through the emergency oil pump 131 and the reversing valve 14 into the steering actuator 11. The oil output from the emergency oil pump 131 is delivered to the steering actuator 11 to drive it to generate steering assistance. Thus, when the main circuit 12 is in a faulty state, the emergency circuit 13 provides the necessary hydraulic energy to the steering actuator 11, ensuring that the vehicle still has basic and continuous steering control capability.

[0046] In some embodiments, such as Figures 1-4 As shown, the main circuit 12 includes a main oil pump 121. As the core power component in the main circuit 12 of the hydraulic steering system 1, the main oil pump 121 continuously supplies oil to the steering actuator 11 under normal working conditions, thereby realizing hydraulic power assistance for the vehicle's steering action and ensuring that the steering wheel operating force meets regulatory requirements and the actual use needs of the vehicle.

[0047] In some embodiments, the main oil pump 121 may be a gear pump, vane pump, piston pump or other hydraulic pump suitable for the hydraulic steering system 1, and its main function is to convert mechanical energy into hydraulic energy to provide the required hydraulic pressure and flow to the steering actuator 11.

[0048] In some embodiments, the inlet of the main oil pump 121 is connected to the outlet of the oil tank 5, the outlet of the main oil pump 121 is connected to the steering actuator 11, and the drive end of the main oil pump 121 is connected to the engine 2 or the drive motor 3.

[0049] In some embodiments, when the engine 2, drive motor 3, and power battery are in normal operating condition, the engine 2 or the drive motor 3 powered by the power battery provides driving power to the main oil pump 121, causing the main oil pump 121 to continuously draw oil from the oil tank 5 and pressurize the oil before delivering it to the steering actuator 11. During this process, the high-pressure oil acts on the hydraulic chamber inside the steering actuator 11, assisting the steering force input by the steering wheel to complete the wheel steering, thereby forming a stable and continuous hydraulic power assist effect. After the steering action is completed, the oil completes the circulation return within the system, and the main circuit 12 can continue to work throughout the entire vehicle operation, providing reliable hydraulic support for the steering system.

[0050] In some embodiments, such as Figures 1-4 As shown, the main circuit 12 also includes a check valve 122. The check valve 122 can be a hydraulic valve that only allows oil to flow in one direction and prevents oil from flowing in the opposite direction. Its main function is to ensure that the high-pressure oil output by the main oil pump 121 is stably and reliably delivered to the steering actuator 11 when the main circuit 12 is working normally, and at the same time prevent the oil from flowing back when the pressure changes or the emergency circuit 13 intervenes, thereby ensuring the stability of the oil flow direction in the main circuit 12 and the reliability of the system operation.

[0051] In some embodiments, the check valve 122 can adopt various structural forms, such as ball check valve 122, needle check valve 122, plunger check valve 122 or check valve 122 with spring reset structure, etc. The specific structural form can be selected according to the actual needs such as system pressure level, response speed and installation space, but all of them can realize the one-way flow function of oil.

[0052] In some embodiments, the one-way valve 122 is located on the outlet pipeline connected to the outlet of the main oil pump 121, and the outlet pipeline is connected to the steering actuator 11. The one-way valve 122 is used to control the unidirectional flow of oil from the outlet of the main oil pump 121 to the steering actuator 11. The one-way valve 122 is used to open to supply fluid to the steering actuator 11 when the main circuit 12 is working normally.

[0053] In some embodiments, such as Figures 1-4 As shown, the drive end of the reversing valve 14 is connected between the outlet of the main oil pump 121 and the check valve 122, forming the control circuit 141 of the reversing valve 14. The oil pressure entering the drive end of the reversing valve 14 is consistent with the oil pressure output by the main oil pump 121, which is used to drive the valve core of the reversing valve 14 to switch between different positions.

[0054] In some embodiments, the drive end of the reversing valve 14 can be connected to the control chamber on one side of the valve core. The oil pressure in the control chamber is used to overcome or cooperate with the spring force in the valve core, so that the valve core moves automatically according to the pressure state of the main circuit 12 without the need for additional electrical control devices or manual intervention.

[0055] In some embodiments, when the main oil pump 121 is operating normally, the oil pumped by it drives the directional valve 14 to move to the first position. Specifically, when the main oil pump 121 is operating normally, the high-pressure oil pumped by the main oil pump 121 is not only delivered to the steering actuator 11 via the check valve 122, but also acts on the drive end of the directional valve 14 through the control circuit 141 of the directional valve 14, thereby pushing the valve core of the directional valve 14 to move to the first position against the elastic force of the spring, so that the outlet of the emergency oil pump 131 is connected to the oil return port of the oil tank 5, and the emergency circuit 13 does not participate in the steering assist. When the main oil pump 121 loses its output of high-pressure oil due to a failure of the engine 2, drive motor 3, or power battery, the oil pressure in the control circuit 141 of the reversing valve 14 disappears. The drive end of the reversing valve 14 is no longer subjected to hydraulic pressure, and the valve core automatically moves to the second position in the opposite direction under the action of the spring return force. This allows the oil output from the emergency oil pump 131 to enter the steering actuator 11, pushing the piston of the steering actuator 11 to generate power assistance. Thus, automatic and reliable switching between the main circuit 12 and the emergency circuit 13 is achieved without the need for electronic control or manual intervention.

[0056] The following is for reference. Figure 5 A control method for a hydraulic steering system according to an embodiment of the present invention is described, the method being used to control the hydraulic steering system described in the above embodiment.

[0057] Figure 5 This is a flowchart of a control method for a hydraulic steering system according to an embodiment of the present invention, such as... Figure 5 As shown, the control method of the hydraulic steering system in this embodiment of the invention includes at least steps S1-S2, as detailed below: S1, when the main circuit of the hydraulic steering system is in normal working condition, the main circuit provides oil to the steering actuator of the hydraulic steering system, and the emergency circuit of the hydraulic steering system does not intervene in the steering drive.

[0058] Specifically, when the main circuit of the hydraulic steering system is in normal working condition, the engine or a drive motor powered by the power battery serves as the drive source, driving the main oil pump. The main oil pump draws oil from the outlet of the oil tank, pressurizes it, and then supplies oil to the steering actuator through the outlet pipe of the main oil pump. This causes the piston in the steering actuator to generate hydraulic assistance when the driver performs steering operations, thereby achieving normal steering control of the vehicle. Under normal working condition of the main circuit, the valve core of the reversing valve is in the first position, connecting the outlet of the emergency oil pump to the return port of the oil tank. The oil supplied by the emergency oil pump in the emergency circuit does not enter the steering actuator but flows directly back to the oil tank through the reversing valve. Therefore, the emergency circuit does not participate in steering drive and exists only in a standby state; the entire steering assistance process is completed independently by the main circuit.

[0059] S2, when the main circuit is in a faulty state, the emergency circuit supplies oil to the steering actuator of the hydraulic steering system. The emergency circuit uses the vehicle's drive axle as the driving source.

[0060] Specifically, when the main circuit of the hydraulic steering system is in a faulty state, the main oil pump stops supplying oil to the steering actuator, and the main circuit can no longer provide steering assistance to the steering actuator. At this time, the valve core of the reversing valve switches to the second position, and the outlet of the emergency oil pump in the emergency circuit is connected to the steering actuator. The emergency circuit forms an oil flow path from the oil tank outlet, through the emergency oil pump, and then through the reversing valve into the steering actuator, so that the emergency circuit can supply oil to the steering actuator, push the piston in the steering actuator to generate hydraulic assistance, thereby maintaining the vehicle's steering assistance function in the event of a main circuit failure, and realizing the basic steering control requirements of the vehicle during driving.

[0061] According to the control method of the hydraulic steering system of the present invention, when the main circuit is in normal working condition, the emergency circuit is controlled not to intervene in the steering drive, so that the steering actuator is only supplied with oil by the main circuit driven by the drive motor powered by the engine or power battery. This ensures that the hydraulic steering system operates stably in the existing manner under normal working conditions, avoids unnecessary energy consumption or system interference caused by the emergency circuit participating in the work, and ensures the stability and consistency of the steering assist output. When the main circuit fails to supply hydraulic fluid due to engine, motor, or power battery malfunction, the emergency circuit automatically intervenes by switching the steering drive path and uses the vehicle's drive axle as the drive source to supply fluid to the steering actuator. Since the rotation of the drive axle originates from the kinetic energy transmitted by the wheels during vehicle movement, it can continuously output power even when the vehicle is still in a state of inertial driving or on an incline. Therefore, this method achieves seamless switching and continuous supply of steering assist in the event of main circuit failure, avoiding sudden changes in steering force caused by a sudden interruption of the power source. At the same time, it does not rely on the low-voltage battery and its electrical circuit, thus avoiding risks such as low-voltage circuit overload and fuse blowout from the control strategy level. This ensures that the emergency circuit always has a usable power source during vehicle movement, thereby guaranteeing the vehicle's steering control capability even when the main circuit fails, and improving the safety and reliability of steering operation.

[0062] In some embodiments, such as Figure 1 and Figure 2 As shown, under normal operating conditions of the main circuit, the check valve in the hydraulic steering system is turned on and drives the directional valve to move to the first position.

[0063] Specifically, when the main circuit of the hydraulic steering system is in normal operation, the main oil pump, as the power source of the main circuit, continuously pumps pressurized hydraulic fluid under the drive of the engine or motor, forming a stable output pressure at the outlet of the main oil pump. The outlet of the main oil pump is connected to a check valve through an outlet pipeline, which continuously pumps hydraulic fluid to the steering actuator. Furthermore, a control circuit for driving the directional control valve is provided between the check valve and the outlet of the main oil pump. When hydraulic fluid enters the drive end of the directional control valve through the control circuit, it applies a driving force to the valve core. Under the action of this driving force, the valve core of the directional control valve overcomes the elastic force of its return spring or other return structure and is driven to the first position, disconnecting the path between the emergency oil pump and the steering actuator, and connecting the outlet of the emergency oil pump to the return port of the oil tank. This ensures that the emergency circuit does not participate in steering assist when the main circuit is supplying oil normally.

[0064] In some embodiments, under normal operating conditions of the main circuit, the emergency oil pump in the emergency circuit pumps oil as the drive axle's drive bevel gear rotates during vehicle operation, and the oil pumped by the emergency oil pump is unloaded through a reversing valve.

[0065] Specifically, when the vehicle is in motion, the emergency oil pump in the emergency circuit remains mechanically connected to the drive bevel gear of the vehicle's drive axle. Therefore, regardless of whether the main circuit is operating, the emergency oil pump will rotate synchronously with the drive bevel gear of the drive axle and pump oil. When the main circuit is operating normally, because the reversing valve is in the first position, the oil pumped by the emergency oil pump does not enter the steering actuator but flows directly back to the oil tank through the reversing valve, thus creating an unloaded state. Unloaded means that although the emergency oil pump pumps oil, its output oil does not build up working pressure on the steering actuator but flows back under low resistance conditions to avoid interference between the emergency circuit and the main circuit. This also ensures that the emergency oil pump is always in a standby state ready to immediately participate in operation, providing conditions for rapid switching in the event of a subsequent main circuit failure.

[0066] In some embodiments, such as Figure 3 and Figure 4 As shown, in the fault state of the main circuit, the main oil pump of the main circuit stops working, the driving force of the reversing valve in the emergency circuit disappears, and the reversing valve automatically switches to the second position under the action of spring force.

[0067] Specifically, when the main circuit of the hydraulic steering system is in a faulty state, such as when the engine stalls, the drive motor stops working, or the power battery malfunctions, the main oil pump stops pumping oil, and its outlet pressure disappears. The directional valve control circuit connecting the main oil pump outlet and the check valve no longer has hydraulic driving force. In this situation, the valve core of the directional valve automatically returns to its original position and switches to the second position under the action of its internal elastic reset element (such as spring force), connecting the path between the emergency circuit and the steering actuator. Simultaneously, due to the check valve, high-pressure oil cannot flow back into the directional valve control circuit via the check valve, thus preventing the high-pressure oil supplied by the emergency circuit from interfering with the directional valve control circuit and ensuring the continuous and stable operation of the emergency circuit after the main circuit fails.

[0068] In some embodiments, in the event of a failure in the main circuit, the drive bevel gear of the drive axle drives the emergency oil pump in the emergency circuit through one or more constant mesh gear pairs while the vehicle is in motion. The oil pumped by the emergency oil pump is supplied to the steering actuator through a reversing valve to perform steering actions.

[0069] Specifically, when the vehicle is in motion and a main circuit malfunctions, although the main oil pump stops working, the vehicle will continue to move forward a certain distance due to inertia or gravity while driving on an incline. During this process, the vehicle's wheels drive the driving bevel gear in the drive axle to rotate in the reverse direction through the transmission path formed by the half-shaft, half-shaft gear, differential housing, and driven bevel gear. The driving bevel gear then transmits the rotation to the emergency oil pump in the emergency circuit through one or more constantly meshed gear pairs, enabling the emergency oil pump to continue pumping oil even without the participation of the engine or drive motor. As the vehicle speed gradually decreases, the speed of the emergency oil pump decreases accordingly, and its hydraulic assist output gradually decreases until the vehicle comes to a complete stop, thus matching the actual motion state of the vehicle.

[0070] In some embodiments, when the main circuit fault is cleared and the main oil pump resumes normal operation, the main oil pump resumes pumping oil to the steering actuator. The hydraulic pressure formed on its outlet side re-enters the control circuit of the directional valve, thereby driving the directional valve spool to overcome the elastic reset force and automatically switch back to the first position. In this state, the oil pumped by the emergency oil pump no longer enters the steering actuator, but flows directly back to the oil tank through the directional valve, entering an unloaded state. This causes the emergency circuit to automatically disengage from power steering, and the main circuit resumes the power steering function, achieving automatic switching between the main circuit and the emergency circuit without manual intervention or additional control commands.

[0071] In some embodiments, the emergency oil pump is driven by one or more constant meshing gear pairs via an active bevel gear in the drive axle, and can be flexibly arranged with an adjustable speed ratio to adapt to different working conditions.

[0072] This invention also proposes an electrical device for implementing the control method of the hydraulic steering system described in the above embodiments.

[0073] Alternatively, in some embodiments, the electrical equipment is a vehicle, such as... Figure 6 As shown, vehicle 100 includes the hydraulic steering system 1 described in the above embodiment, and / or vehicle 100 is used to implement the control method of the hydraulic steering system described in the above embodiment.

[0074] According to the embodiments of the present invention, by employing the hydraulic steering system 1 and / or the control method of the hydraulic steering system described in the above embodiments, the electrical equipment can still provide hydraulic assistance through the emergency circuit 13 when the main circuit 12 fails. The emergency circuit 13 uses the drive axle 4 as the drive source, so that the vehicle 100 can still maintain steering control capability when the main circuit 12 fails, thereby improving the safety and reliability of vehicle steering operation.

[0075] In some embodiments, vehicle 100 may be a conventional energy vehicle or a new energy vehicle.

[0076] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0077] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A hydraulic steering system, characterized in that, include: Steering actuator, used to perform steering actions by means of hydraulic fluid; The main circuit, which uses a drive motor powered by an engine or a power battery as a drive source, is used to pump oil to the steering actuator during normal operation. An emergency circuit, which is connected to the vehicle's drive axle and uses the drive axle as a drive source, is used to pump oil to the steering actuator when the main circuit is in a fault state.

2. The hydraulic steering system according to claim 1, characterized in that, The emergency circuit includes an emergency oil pump, which is driven by one or more constantly meshing gear pairs via gears on the drive axle's drive bevel gear shaft.

3. The hydraulic steering system according to claim 2, characterized in that, The inlet of the emergency oil pump is connected to the outlet of the oil tank; The hydraulic steering system also includes: A reversing valve is connected via a pipeline to the oil return port of the oil tank, the outlet of the emergency oil pump, and the steering actuator. When the reversing valve is in the first position, the outlet of the emergency oil pump is connected to the oil return port of the oil tank. When the reversing valve is in the second position, the outlet of the emergency oil pump is connected to the steering actuator.

4. The hydraulic steering system according to claim 3, characterized in that, The main circuit includes a main oil pump, the inlet of which is connected to the outlet of the oil tank, the outlet of which is connected to the steering actuator, and the drive end of which is connected to the engine or the drive motor.

5. The hydraulic steering system according to claim 4, characterized in that, The main circuit also includes a check valve located on the outlet pipe connected to the outlet of the main oil pump. The outlet pipe is connected to the steering actuator. The check valve is used to control the unidirectional flow of oil from the outlet of the main oil pump to the steering actuator. The check valve is used to open to supply fluid to the steering actuator when the main circuit is working normally.

6. The hydraulic steering system according to claim 5, characterized in that, The drive end of the reversing valve is connected between the outlet of the main oil pump and the check valve. When the main oil pump is working normally, the pumped oil drives the reversing valve to move to the first position.

7. A control method for a hydraulic steering system, characterized in that, The control method for controlling the hydraulic steering system according to any one of claims 1-6 includes: When the main circuit of the hydraulic steering system is in normal working condition, the main circuit supplies oil to the steering actuator of the hydraulic steering system, and the emergency circuit of the hydraulic steering system does not intervene in the steering drive. When the main circuit is in a faulty state, the emergency circuit supplies oil to the steering actuator of the hydraulic steering system, and the emergency circuit uses the vehicle's drive axle as the driving source.

8. The control method for the hydraulic steering system according to claim 7, characterized in that, Under normal operating conditions of the main circuit, the one-way valve in the hydraulic steering system is turned on and drives the reversing valve to move to the first position. The emergency oil pump in the emergency circuit pumps oil as the drive axle's drive bevel gear rotates during vehicle operation. The oil pumped by the emergency oil pump is unloaded through the reversing valve.

9. The control method for the hydraulic steering system according to claim 7, characterized in that, In the fault state of the main circuit, the main oil pump of the main circuit stops working, the driving force of the reversing valve in the emergency circuit disappears, and the reversing valve automatically switches to the second position under the action of spring force. When the vehicle is in motion, the driving bevel gear of the drive axle drives the emergency oil pump in the emergency circuit through one or more constant mesh gear pairs. The oil pumped by the emergency oil pump is supplied to the steering actuator through the reversing valve to perform the steering action.

10. An electrical appliance, characterized in that, The electrical equipment is used to implement the control method of the hydraulic steering system according to any one of claims 7-9, or the electrical equipment is a vehicle, the vehicle including the hydraulic steering system according to any one of claims 1-6 and / or implementing the control method of the hydraulic steering system according to any one of claims 7-9.

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