Special vehicle and its all-wheel steering system

Abstract

The present invention provides a full-wheel steering system for a special vehicle. The full-wheel steering system includes a power unit, a front-wheel steering device, and a rear-wheel steering device. The front-wheel steering device includes a front-wheel steering axle, a front-wheel hydraulic cylinder, and a steering gear; the front-wheel hydraulic cylinder is connected to the power unit via the steering gear. In the rear-wheel steering device, a switching unit is respectively connected to the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder, and is capable of establishing or releasing the connection between the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder. In the special vehicle and its full-wheel steering system of the present invention, the switching unit can establish or release the connection between the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder. When the front-wheel hydraulic cylinder is connected to the rear-wheel hydraulic cylinder, the special vehicle can achieve full-wheel steering, thereby improving the mobility of the vehicle and effectively improving the operation efficiency of the special vehicle; when the connection between the front-wheel hydraulic cylinder and the rear-wheel hydraulic cylinder is disconnected, the special vehicle only has front-wheel steering and the rear-wheel steering is restricted, ensuring the stability and safety of the vehicle during driving.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle steering, in particular to a special vehicle and an all-wheel steering system thereof. Background Art

[0002] For existing special vehicles, they need to have a lower speed during operation, which places great demands on the vehicle's maneuverability in order to effectively improve the operating efficiency of the special vehicles; while in non-working states such as transfers, special vehicles should travel at medium to high speeds, and the rear-wheel steering function should be limited at this time to ensure the stability and safety of the vehicle's driving. Summary of the invention

[0003] The object of the present invention is to provide a special vehicle and an all-wheel steering system to realize all-wheel steering and to selectively control whether the all-wheel steering is executed, thereby improving the maneuverability of the vehicle and ensuring its stability and safety during driving.

[0004] To achieve the above-mentioned purpose, the present invention provides an all-wheel steering system for a special vehicle, comprising: a power unit, a front-wheel steering device, and a rear-wheel steering device, wherein the front-wheel steering device comprises a front-wheel steering axle, a front-wheel hydraulic cylinder, and a steering gear; the front-wheel hydraulic cylinder is connected to the power unit via the steering gear, and when the power unit provides power to the steering gear, the steering gear drives the front-wheel steering axle to steer through the front-wheel hydraulic cylinder; the rear-wheel steering device comprises a rear-wheel steering axle, a rear-wheel hydraulic cylinder, and a switching unit, wherein the switching unit is respectively connected to the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder, and can establish or release the connection between the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder; when the rear-wheel hydraulic cylinder is connected to the front-wheel hydraulic cylinder, the rear-wheel hydraulic cylinder drives the rear-wheel steering axle to steer.

[0005] Preferably, the power unit includes a fluid reservoir and a hydraulic pump; the steering gear has an oil inlet, an oil return port, a first working oil port and a second working oil port; the oil inlet is connected to the fluid reservoir via the hydraulic pump, and the oil return port is directly connected to the fluid reservoir; the front wheel hydraulic cylinder has a first hydraulic chamber and a second hydraulic chamber; the first hydraulic chamber is connected to the first working oil port, and the second hydraulic chamber is connected to the second working oil port; the rear wheel hydraulic cylinder is selectively connected between the second hydraulic chamber and the second working oil port via the switching unit, or connected to the fluid reservoir.

[0006] Preferably, the switching unit includes two switching valves, two switching valves; the rear wheel hydraulic cylinder has two hydraulic chambers, one of which is selectively connected to the second hydraulic chamber of the front wheel hydraulic cylinder through one switching valve, or is connected to the fluid storage tank; the other hydraulic chamber of the rear wheel hydraulic cylinder is selectively connected to the second working oil port of the steering gear through another switching valve, or is connected to the fluid storage tank.

[0007] Preferably, the all-wheel steering system is also provided with an on-off valve, which is arranged on the connecting passage between the second hydraulic chamber of the front wheel hydraulic cylinder and the second working oil port of the steering gear; the on-off valve is linked to the switching valve; when the on-off valve is turned on, the second hydraulic chamber of the front wheel hydraulic cylinder is connected with the second working oil port of the steering gear through the on-off valve, and the rear wheel hydraulic cylinder is directly connected with the fluid storage tank through the switching valve; when the on-off valve is turned off, the rear wheel hydraulic cylinder is connected between the second hydraulic chamber of the front wheel hydraulic cylinder and the second working oil port of the steering gear through the switching valve.

[0008] Preferably, the rear-wheel steering device further comprises a centering cylinder, which is respectively connected to the power unit and the rear-wheel steering axle; the power unit provides power to the centering cylinder so as to center and lock the rear-wheel steering axle through the centering cylinder.

[0009] Preferably, the all-wheel steering system also includes a pressure-maintaining pipeline, which connects the power unit to the centering cylinder; a shut-off valve and an energy storage tank are provided on the pressure-maintaining pipeline, and the shut-off valve is arranged between the power unit and the energy storage tank; the shut-off valve is connected to a pressure switch, and the pressure switch controls the shut-off valve according to the pressure value of the pressure-maintaining pipeline to connect or cut off the pressure-maintaining pipeline.

[0010] Preferably, the pressure-maintaining pipeline is provided with a one-way valve allowing one-way conduction from the power unit to the energy storage tank.

[0011] Preferably, the oil outlet of the centering cylinder is connected to the power unit via a pressure relief pipeline, and a pressure protection valve is provided on the pressure relief pipeline.

[0012] The present invention also provides a special vehicle, comprising the above-mentioned all-wheel steering system.

[0013] It can be seen from the above technical solution that the beneficial effects of the present invention are:

[0014] In the special vehicle and all-wheel steering system thereof of the present invention, the switching unit can establish or release the connection between the rear wheel hydraulic cylinder and the front wheel hydraulic cylinder. When the front wheel hydraulic cylinder is connected to the rear wheel hydraulic cylinder, the special vehicle can achieve all-wheel steering, thereby improving the maneuverability of the vehicle and effectively improving the operating efficiency of the special vehicle; when the front wheel hydraulic cylinder is disconnected from the rear wheel hydraulic cylinder, the special vehicle only has front wheel steering, and the rear wheel steering is restricted, thereby ensuring the stability and safety of the vehicle's driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the principle of a preferred embodiment of the all-wheel steering system of a special vehicle of the present invention.

[0016] The description of the reference numerals is as follows: 1. All-wheel steering system; 11. Power unit; 111. Liquid storage tank; 112. Hydraulic pump; 12. Front-wheel steering axle; 13. Front-wheel hydraulic cylinder; 14. Steering gear; 15. Rear-wheel steering axle; 16. Rear-wheel hydraulic cylinder; 17. Switching unit; 171. First switching valve; 172. Second switching valve; 18. On-off valve; 19. Centering cylinder; 20. Pressure-holding pipeline; 21. Shut-off valve; 22. Accumulator tank; 23. Pressure switch; 24. Check valve; 30. Pressure-relief pipeline; 31. Pressure protection valve. Detailed implementation manners

[0017] Typical implementation manners embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different implementation manners, all of which do not depart from the scope of the present invention, and the descriptions and illustrations therein are for illustrative purposes in essence and are not used to limit the present invention.

[0018] In order to further illustrate the principle and structure of the present invention, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] This application provides a special vehicle and its all-wheel steering system. A steering wheel is configured on the special vehicle, and the all-wheel steering system receives the control of the steering wheel and provides power for the special vehicle, thereby realizing the steering of the special vehicle.

[0020] Refer to Figure 1 , the all-wheel steering system 1 includes a power unit 11, a front-wheel steering device, and a rear-wheel steering device. The front-wheel steering device acts on the front wheels of the special vehicle, and the rear-wheel steering device acts on the rear wheels of the special vehicle.

[0021] Specifically, the power unit 11 includes a liquid storage tank 111 and a hydraulic pump 112. The hydraulic pump 112 is connected to the liquid storage tank 111, and the hydraulic pump 112 receives the control of the steering wheel.

[0022] The front-wheel steering device includes a front-wheel steering axle 12, a front-wheel hydraulic cylinder 13, and a steering gear 14. The front-wheel hydraulic cylinder 13 is connected to the hydraulic pump 112 through the steering gear 14, and the liquid storage tank 111 provides hydraulic power to the steering gear 14 through the hydraulic pump 112, so that the steering gear 14 drives the front-wheel steering axle 12 to turn through the front-wheel hydraulic cylinder 13.

[0023] In this embodiment, the steering gear 14 has an oil inlet P port, an oil return port T port, a first working oil port A port, and a second working oil port B port. The front-wheel hydraulic cylinder 13 has a rod hydraulic chamber and a rodless hydraulic chamber. Specifically, the P port of the steering gear 14 is connected to the hydraulic pump 112, and the T port of the steering gear 14 is connected to the liquid storage tank 111; the A port of the steering gear 14 is connected to the rodless hydraulic chamber of the front-wheel hydraulic cylinder 13, and the rod hydraulic chamber of the front-wheel hydraulic cylinder 13 is connected to the B port of the steering gear 14.

[0024] The rear-wheel steering device includes a rear-wheel steering axle 15, a rear-wheel hydraulic cylinder 16, and a switching unit 17. The switching unit 17 is respectively connected to the rear-wheel hydraulic cylinder 16 and the front-wheel hydraulic cylinder 13, and can establish or release the connection between the rear-wheel hydraulic cylinder 16 and the front-wheel hydraulic cylinder 13. When the connection between the rear-wheel hydraulic cylinder 16 and the front-wheel hydraulic cylinder 13 is established, the rear-wheel hydraulic cylinder 16 drives the rear-wheel steering axle 15 to turn.

[0025] In this embodiment, the rear-wheel hydraulic cylinder 16 has a rod hydraulic chamber and a rodless hydraulic chamber. The switching unit 17 includes two switching valves. Both of the two switching valves in this embodiment are two-position three-way valves, which have a first valve port, a second valve port, and a third valve port, and have two working states: a spring position and an electromagnetic position. When the switching valve is in the spring position, the first valve port is connected to the second valve port; when the switching valve is in the electromagnetic position, the first valve port is connected to the third valve port.

[0026] Specifically, the two switching valves in this embodiment are respectively a first switching valve 171 and a second switching valve 172. The first valve port of the first switching valve 171 is connected to the rod hydraulic chamber of the front-wheel hydraulic cylinder 13, the second valve port of the first switching valve 171 is connected to the rod hydraulic chamber of the rear-wheel hydraulic cylinder 16, and the third valve port of the first switching valve 171 is connected to the liquid storage tank 111. The first valve port of the second switching valve 172 is connected to the rodless hydraulic chamber of the rear-wheel hydraulic cylinder 16, the second valve port of the second switching valve 172 is connected to port B of the steering gear 14, and the third valve port of the second switching valve 172 is connected to the oil storage tank.

[0027] Figure 1 In the shown structure, the front-wheel hydraulic cylinder 13 and the rear-wheel hydraulic cylinder 16 in this embodiment are both arranged horizontally. However, in the actual structure, it is not limited to this arrangement form. The front-wheel hydraulic cylinder 13 and the rear-wheel hydraulic cylinder 16 can also be arranged longitudinally or in other forms as long as they can drive the front-wheel steering axle 12 and the rear-wheel steering axle 15.

[0028] In other embodiments, the first switching valve 171 and the second switching valve 172 can also be replaced with two-position four-way valves or other valve components as long as they can selectively establish or release the connection between the rear-wheel hydraulic cylinder 16 and the front-wheel hydraulic cylinder 13.

[0029] Further, the all-wheel steering system 1 is also provided with a cut-off valve 18, and this cut-off valve 18 is arranged on the connection passage between the rod hydraulic chamber of the front-wheel hydraulic cylinder 13 and port B of the steering gear 14.

[0030] In this embodiment, the on-off valve 18 is linked with the first switching valve 171 and the second switching valve 172. When the on-off valve 18 is turned on, both the first switching valve 171 and the second switching valve 172 are in the electromagnetic position. The rod hydraulic chamber of the front-wheel hydraulic cylinder 13 is connected to port B of the steering gear 14 through the on-off valve 18, and the rear-wheel hydraulic cylinder 16 is connected to the liquid storage tank 111 through the first switching valve 171 and the second switching valve 172. At this time, the hydraulic pump 112 provides hydraulic power to the front-wheel hydraulic cylinder 13 through the steering gear 14, so that the front-wheel hydraulic cylinder 13 drives the front-wheel steering axle 12, thereby realizing the front-wheel steering of the special vehicle.

[0031] When the on-off valve 18 is turned off, both the first switching valve 171 and the second switching valve 172 are in the spring position. The rod hydraulic chamber of the front-wheel hydraulic cylinder 13 is connected to the rod hydraulic chamber of the rear-wheel hydraulic cylinder 16 through the first switching valve 171, and the rodless hydraulic chamber of the rear-wheel hydraulic cylinder 16 is connected to port B of the steering gear 14 through the second switching valve 172. At this time, the hydraulic pump 112 provides hydraulic power to the front-wheel hydraulic cylinder 13 and the rear-wheel hydraulic cylinder 16 through the steering gear 14, so that the front-wheel hydraulic cylinder 13 drives the front-wheel steering axle 12 and the rear-wheel hydraulic cylinder 16 drives the rear-wheel steering axle 15, thereby realizing the rear-wheel steering of the special vehicle.

[0032] In addition, in the all-wheel steering system 1 of this embodiment, the rear-wheel steering device further includes a centering cylinder 19. The centering cylinder 19 is respectively connected to the power unit 11 and the rear-wheel steering axle 15. The power unit 11 provides power to the centering cylinder 19 to center and lock the rear-wheel steering axle 15 through the centering cylinder 19.

[0033] In other embodiments, a power device may also be added and connected to the centering cylinder 19. That is, a supercharging power pump and an oil tank, so that the oil tank is connected to the centering cylinder 19 through the power pump.

[0034] Furthermore, the all-wheel steering system 1 further includes a pressure-holding pipeline 20, and the pressure-holding pipeline 20 connects the liquid storage tank 111 to the centering cylinder 19. The pressure-holding pipeline 20 of this embodiment shares a power source with the steering, so as to effectively reduce the components in the all-wheel steering system 1 and make its structure more compact.

[0035] In this embodiment, a cut-off valve 21 and an energy storage tank 22 are provided on the pressure-holding pipeline 20, and the cut-off valve 21 is arranged between the liquid storage tank 111 and the energy storage tank 22. The on-off valve 18 is connected to a pressure switch 23, and the pressure switch 23 controls the on and off of the cut-off valve 21 according to the pressure value in the pressure-holding pipeline 20, so as to connect or cut off the pressure-holding pipeline 20.

[0036] When the pressure value inside the energy storage tank 22 is lower than the set requirement, that is, when the pressure value in the pressure maintaining pipeline 20 is lower than the set requirement, the pressure switch 23 controls the cut-off valve 21 to be turned on, and the liquid storage tank 111 pressurizes the energy storage tank 22 through the hydraulic pump 112, so as to ensure the normal pressure value in the pressure maintaining pipeline 20.

[0037] Preferably, a one-way valve 24 that allows one-way conduction from the liquid storage tank 111 to the energy storage tank 22 is provided on the pressure maintaining pipeline 20 to prevent the hydraulic oil in the energy storage tank 22 from flowing back to the liquid storage tank 111.

[0038] In addition, a pressure relief pipeline 30 is also provided in the steering system. The pressure relief pipeline 30 connects the oil outlet of the centering cylinder 19 and communicates with the liquid storage tank 111, and a pressure protection valve 31 is provided on the pressure relief pipeline 30.

[0039] During the steering process, when the pressure value of the centering cylinder 19 exceeds the set range, the hydraulic oil of the centering cylinder 19 flows out from the oil outlet, passes through the pressure relief pipeline 30 and flows through the pressure protection valve 31 into the pressure protection valve 31, so as to ensure the normal pressure value in the pipeline and realize pressure relief.

[0040] The working principle of the all-wheel steering system 1 of the present application is as follows:

[0041] When the on-off valve 18 is turned on, both the first switching valve 171 and the second switching valve 172 are in the electromagnetic position. The front wheel hydraulic cylinder 13 is connected to the second working oil port of the steering gear 14 through the on-off valve 18, and there is a disconnected connection relationship between the rear wheel hydraulic cylinder 16 and the front wheel hydraulic cylinder 13 and the steering gear 14. The liquid storage tank 111 provides hydraulic power to the front wheel hydraulic cylinder 13 through the hydraulic pump 112 via the steering gear 14, so that the front wheel hydraulic cylinder 13 drives the front wheel steering axle 12. At this time, the special vehicle only has front wheel steering.

[0042] When the on-off valve 18 is turned off, both the first switching valve 171 and the second switching valve 172 are in the spring position. The front wheel hydraulic cylinder 13 is connected to the rear wheel hydraulic cylinder 16 through the first switching valve 171, and the rear wheel hydraulic cylinder 16 is connected to the second working oil port of the steering gear 14 through the second switching valve 172. The liquid storage tank 111 provides hydraulic power to the front wheel hydraulic cylinder 13 and the rear wheel hydraulic cylinder 16 through the hydraulic pump 112 via the steering gear 14, so that the front wheel hydraulic cylinder 13 drives the front wheel steering axle 12 and the rear wheel hydraulic cylinder 16 drives the rear wheel steering axle 15, thereby realizing all-wheel steering of the special vehicle.

[0043] In summary, in the special vehicle and its all-wheel steering system of the present application, the switching unit can establish or release the connection between the rear wheel hydraulic cylinder and the front wheel hydraulic cylinder. When the front wheel hydraulic cylinder is connected to the rear wheel hydraulic cylinder, the special vehicle can achieve all-wheel steering, thereby improving the maneuverability of the vehicle and effectively improving the operating efficiency of the special vehicle; when the front wheel hydraulic cylinder is disconnected from the rear wheel hydraulic cylinder, the special vehicle only has front wheel steering, and the rear wheel steering is restricted, ensuring the stability and safety of the vehicle.

[0044] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A full-wheel steering system for a special vehicle, characterized in that include: Power unit; The power unit includes a fluid storage tank and a hydraulic pump; A front wheel steering device comprises a front wheel steering axle, a front wheel hydraulic cylinder and a steering gear; the front wheel hydraulic cylinder is connected to a hydraulic pump of the power unit via the steering gear, and when the power unit provides power to the steering gear, the steering gear drives the front wheel steering axle to steer via the front wheel hydraulic cylinder; The steering gear has an oil inlet, an oil return port, a first working oil port and a second working oil port; the oil inlet is connected to the liquid storage tank via the hydraulic pump, and the oil return port is directly connected to the liquid storage tank; The front wheel hydraulic cylinder has a first hydraulic chamber and a second hydraulic chamber; the first hydraulic chamber is connected to the first working oil port, and the second hydraulic chamber is connected to the second working oil port; A rear-wheel steering device, comprising a rear-wheel steering axle, a rear-wheel hydraulic cylinder and a switching unit, wherein the switching unit is respectively connected to the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder, and is capable of establishing or canceling the connection between the rear-wheel hydraulic cylinder and the front-wheel hydraulic cylinder; when the rear-wheel hydraulic cylinder is connected to the front-wheel hydraulic cylinder, the rear-wheel hydraulic cylinder drives the rear-wheel steering axle to steer, and when the rear-wheel hydraulic cylinder is disconnected from the front-wheel hydraulic cylinder, the rear-wheel hydraulic cylinder is connected to the fluid storage tank of the hydraulic pump; The rear wheel hydraulic cylinder is selectively connected between the second hydraulic chamber and the second working oil port through the switching unit, or connected to the liquid storage tank; The switching unit includes two switching valves, which are respectively a first switching valve and a second switching valve; The rear wheel hydraulic cylinder has two hydraulic chambers, one of which is selectively connected to the second hydraulic chamber of the front wheel hydraulic cylinder or to the fluid storage tank via the first switching valve; The other hydraulic chamber of the rear wheel hydraulic cylinder is selectively connected to the second working oil port of the steering gear or to the fluid storage tank via the second switching valve; The all-wheel steering system is also provided with an on-off valve, which is arranged on the connecting passage between the second hydraulic chamber of the front wheel hydraulic cylinder and the second working oil port of the steering gear; The on-off valve is linked with the first and second switching valves; When the on-off valve is turned on, the second hydraulic chamber of the front wheel hydraulic cylinder is connected to the second working oil port of the steering gear through the on-off valve, and the rear wheel hydraulic cylinder is directly connected to the liquid storage tank through the first and second switching valves; When the on-off valve is disconnected, one hydraulic chamber of the rear wheel hydraulic cylinder is connected to the second hydraulic chamber of the front wheel hydraulic cylinder via the first switching valve, and the other hydraulic chamber of the rear wheel hydraulic cylinder is connected to the second working oil port of the steering gear via the second switching valve; The rear-wheel steering device further comprises a centering cylinder, which is connected to the power unit and the rear-wheel steering axle respectively; the power unit provides power to the centering cylinder so as to center and lock the rear-wheel steering axle through the centering cylinder; The oil outlet of the centering cylinder is connected to the power unit via a pressure relief pipeline, and a pressure protection valve is provided on the pressure relief pipeline; The all-wheel steering system further includes a pressure maintaining pipeline, which connects the liquid storage tank to the centering cylinder. A cut-off valve and an energy storage tank are provided on the pressure maintaining pipeline, and the cut-off valve is arranged between the hydraulic pump and the energy storage tank.

2. The all-wheel steering system according to claim 1, wherein, The cut-off valve is connected to a pressure switch, and the pressure switch controls the on-off of the cut-off valve according to the pressure value of the pressure maintaining pipeline to connect or cut off the pressure maintaining pipeline.

3. The all-wheel steering system according to claim 2, characterized in that, A one-way valve that allows unidirectional conduction from the power unit to the energy storage tank is provided on the pressure maintaining pipeline.

4. A special vehicle, characterized in that, An all-wheel steering system according to any one of claims 1 to 3 is included.

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