Dual front axle power steering system and vehicle

Abstract

The utility model provides a kind of double front axle power-assisted steering system and vehicle, belong to vehicle steering system technical field, including double-loop power steering gear, oil tank, power-assisted pump one, power-assisted pump two, emergency pump, emergency valve, power cylinder one and power cylinder two, power cylinder one and power cylinder two are two front axle power of vehicle;Power-assisted pump one provides pressure oil for power cylinder one being arranged in front axle one by double-loop power steering gear, and power-assisted pump two provides pressure oil for power cylinder two being arranged in front axle two by double-loop power steering gear.Power-assisted pump one and power-assisted pump two are driven by the output end of vehicle engine, and emergency pump is driven by gear inside power coupling box;When power-assisted pump one fails, power-assisted pump two can provide power assistance for steering, and when power-assisted pump two fails, emergency pump replaces power-assisted pump two and works.When vehicle loses power and slides, power-assisted pump one and power-assisted pump two stop working, and emergency pump is driven by gear inside power coupling box under the inertia effect of vehicle and continues to provide power assistance for vehicle.

Description

Technical Field

[0001] This utility model belongs to the technical field of vehicle steering systems, and more specifically, relates to a dual front axle power steering system and a vehicle. Background Technology

[0002] Large, heavy-duty vehicles have high load-bearing capacity requirements. Dual-front-axle vehicles, with an additional front axle compared to single-front-axle vehicles, significantly increase their load-bearing capacity. For example, airport fire trucks, with the increasing level of airport fire protection, require 8x8 airport fire trucks with larger liquid carrying capacities. 8x8 airport fire trucks are equipped with four axles, including dual front axles and dual rear axles. The higher load requirements also necessitate greater power steering.

[0003] In the prior art, Chinese invention patent CN107140013A discloses a dual-front-axle automotive steering system. In this system, a single power steering cylinder assembly simultaneously provides power steering to both front axles. The hydraulic power steering pipeline system includes a reservoir, a reservoir outlet pipe, a pump, a steering gear inlet pipe, a steering gear outlet pipe, a left-turn inlet pipe for the power steering cylinder, and a right-turn inlet pipe for the power steering cylinder. During steering, the pump pumps oil from the reservoir into the two chambers of the power steering cylinder to provide power steering. However, for heavily loaded vehicles, a single power steering cylinder is insufficient to provide simultaneous steering assistance to both front axles. Furthermore, if the pump malfunctions, there is a lack of an emergency power steering system, making it difficult to guarantee power steering in emergency situations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this utility model provides a dual front axle power steering system and vehicle. By applying power to both front axles simultaneously through two sets of power steering circuits, it ensures the power steering effect under high loads and can guarantee emergency power steering in the event of a power steering pump failure, thus ensuring driving safety.

[0005] To achieve the above objectives, the present invention provides a dual front axle power steering system, comprising a dual-circuit power steering gear, an oil tank, a power steering pump I, a power steering pump II, an emergency pump, an emergency valve, a power steering cylinder I, and a power steering cylinder II, which respectively assist the two front axles of the vehicle; the dual-circuit power steering gear has a first circuit and a second circuit, the first circuit having an inlet port P1, an outlet port T1, a working port A1, and a working port B1, and the second circuit having an inlet port P2, an outlet port T2, a working port A2, and a working port B2; the emergency valve has an inlet port P3, an inlet port P4, a working port A3, and an outlet port T3; the inlet port P1 is connected to the oil tank through the power steering pump I, the outlet port T1 is connected to the oil tank, and the working port A1... The working oil port B1 is connected to the rodless chamber and rod chamber of the power steering cylinder one, respectively; the oil inlet P3 is connected to the oil tank through the power steering pump two, the oil inlet P4 is connected to the oil tank through the emergency pump, the working oil port A3 is connected to the oil inlet P2, and the oil return ports T3 and T2 are both connected to the oil tank. The working oil ports A2 and B2 are connected to the rodless chamber and rod chamber of the power steering cylinder two, respectively. Under normal operation, the oil inlet P3 is connected to the working oil port A3 and the oil inlet P4 is connected to the oil return port T3. When the power steering pump two is in failure, the oil inlet P4 is connected to the working oil port A3, and the oil inlet P3 and the oil return port T3 are both blocked. Both the power steering pump one and the power steering pump two are driven by the output end of the vehicle engine, and the emergency pump is driven by gears in the vehicle's power coupling box.

[0006] During steering, power steering cylinders one and two apply steering assistance to the front axles. Compared to existing systems that use a single power steering cylinder to provide steering assistance to both front axles, this invention provides stronger steering assistance and distributes it more evenly between the two axles, ensuring effective steering assistance under high loads. Furthermore, if power steering pump one malfunctions and cannot supply oil, power steering pump two can still provide steering assistance under light loads or when steering out of place. If power steering pump two malfunctions and cannot supply oil, an emergency pump can take over the role of power steering pump one to provide assistance. If the vehicle's engine loses power during driving, causing power steering pumps one and two to stop working, the emergency pump, driven by gears in the vehicle's power coupling box, continues to rotate due to the vehicle's inertia during coasting, allowing the emergency pump to continue operating. The dual-circuit power steering system and power steering cylinder two supply hydraulic oil, ensuring some steering assistance is provided even during coasting.

[0007] Optionally, the system also includes a frame and a steering linkage. A dual-circuit power steering system is mounted on the frame, which houses a first front axle and a second front axle. The first front axle has an axle housing and steering knuckle arms at both ends of the first axle housing. The second front axle has an axle housing and steering knuckle arms at both ends of the second axle housing. The output of the dual-circuit power steering system is connected to the first and second steering knuckle arms via the steering linkage. The cylinder of the first power steering cylinder is hinged to the first axle housing, and its output is hinged to one of the first steering knuckle arms. The cylinder of the second power steering cylinder is hinged to the second axle housing, and its output is hinged to one of the second steering knuckle arms. The first and second power steering cylinders provide power assistance to the first and second front axles, respectively.

[0008] Optionally, it also includes a power steering cylinder three, with its rodless chamber connected to working port B1 and its rod chamber connected to working port A1; the steering knuckle arms one located at both ends of axle housing one are the left steering knuckle arm one and the right steering knuckle arm one, respectively, and the steering knuckle arms two located at both ends of axle housing two are the left steering knuckle arm two and the right steering knuckle arm two, respectively. Power steering cylinder one and power steering cylinder two are located on the same side of the frame. The output end of power steering cylinder one is hinged to the left steering knuckle arm one, and the output end of power steering cylinder two is hinged to the left steering knuckle arm two. The cylinder barrel of power steering cylinder three is hinged to axle housing two, and the output end of power steering cylinder three is hinged to the right steering knuckle arm two. Power steering cylinder one and power steering cylinder three are connected in parallel, both driven by power steering pump one and connected to circuit one of the dual-circuit power steering system. That is, power steering pump one simultaneously provides hydraulic pressure for power steering to both front axle one and front axle two.

[0009] Optionally, it also includes a fourth power steering cylinder. The rod-side chamber of the fourth power steering cylinder is connected to the working port A2, and the rodless chamber of the fourth power steering cylinder is connected to the working port B2. The cylinder barrel of the fourth power steering cylinder is hinged to the axle housing, and the output end of the fourth power steering cylinder is hinged to the right steering knuckle arm. The second power steering cylinder and the fourth power steering cylinder are connected in parallel. Both are driven by the second power steering pump and connected to the second circuit of the dual-circuit power steering system. The second power steering pump also provides hydraulic pressure for power steering to both the first and second front axles. In this case, if the first power steering pump fails, the second power steering pump can still apply partial power steering to both the first and second front axles simultaneously. If the second power steering pump fails, the emergency pump takes over and applies partial power steering to both the first and second front axles simultaneously, ensuring a balanced force on both the first and second front axles.

[0010] Optionally, a pressure sensor is installed between the return port T1 and the fuel tank. When the power steering pump 1 fails to supply fuel, although the power steering pump 2 can still provide some assistance, the overall assistance decreases, affecting steering operation. At this time, the return pressure at the return port T1 will be lower than the set value, and the pressure sensor will send a signal to the vehicle control system to issue an alarm, thereby reminding the driver and improving the safety of the steering system.

[0011] Optionally, the dual-circuit power steering system is horizontally fixedly connected to the vehicle frame, with its output end extending vertically downwards and having a steering rocker arm. The steering linkage includes a tie rod, a front control arm, a primary axle tie rod, and a primary axle linkage located at the bottom of the front axle. The primary axle linkage includes a primary axle control arm, a primary axle long tie rod, and a primary axle short tie rod. The primary axle control arm is hinged to the bottom of the axle housing. The primary axle control arm, the left steering knuckle arm, and the right steering knuckle arm are also included. All arms extend towards the rear of the chassis. The first axle control arm also has an extension arm parallel to the axle housing. The two ends of the first axle long tie rod are hinged to the first axle control arm and the left steering knuckle arm, respectively. The two ends of the first axle short tie rod are hinged to the first axle control arm and the right steering knuckle arm, respectively. The front control arm is located between the dual-circuit power steering system and the front axle, and is hinged to the chassis. The two ends of the longitudinal tie rod are hinged to the steering rocker arm and the front control arm, respectively. The two ends of the first axle tie rod are hinged to the front control arm and the extension arm, respectively. When the vehicle is turning, the output of the dual-circuit power steering system drives the steering rocker arm to rotate. The steering rocker arm drives the front control arm to rotate via the longitudinal tie rod. The front control arm drives the first axle control arm to rotate along the axle housing via the first axle tie rod. When the first axle control arm rotates, it drives the left steering knuckle arm and the right steering knuckle arm to rotate via the first axle long tie rod and the first axle short tie rod, respectively, thus achieving the steering operation of the front axle.

[0012] Optionally, the front control arm has a front extension arm, the top of which is hinged to the vehicle frame, and the bottom of the front extension arm extends downward to be flush with the first axle control arm. One end of the longitudinal tie rod is hinged to the steering rocker arm via a ball joint, and the other end of the longitudinal tie rod is hinged to the middle of the front extension arm via a ball joint. One end of the first axle tie rod is hinged to the bottom of the front extension arm via a ball joint, and the other end of the first axle tie rod is hinged to the extension arm via a ball joint. The axle tie rod can extend to the bottom of the front axle via the bottom-extending front extension arm to transmit power from the bottom of the front axle to the first axle linkage. At this time, the first axle tie rod can be in a generally horizontal state. Combined with the downwardly extending dual-circuit power steering output end, this minimizes the length of the longitudinal tie rod and the first axle tie rod that drive the front axle, reducing the transmission path length. The ball joint design prevents jamming at both ends of the longitudinal tie rod and the first axle tie rod due to changes in height during operation.

[0013] Optionally, the steering linkage also includes a second axle linkage located at the bottom of the front axle, and a front transition tie rod, a middle control arm, a rear transition tie rod, a rear control arm, and a second axle tie rod sequentially hinged from the front control arm toward the rear of the frame. The middle control arm and the rear control arm are both hinged to the frame. The second axle linkage includes a second axle control arm, a second axle long tie rod, and a second axle short tie rod. The second axle control arm is hinged to the bottom of the axle housing. The second axle control arm, the left steering knuckle arm, and the right steering knuckle arm all extend toward the rear of the frame. The second axle control arm also has an extension arm two parallel to the axle housing. The two ends of the second axle long tie rod are hinged to the second axle control arm and the left steering knuckle arm two, respectively. The two ends of the second axle short tie rod are hinged to the second axle control arm and the right steering knuckle arm two, respectively. The end of the second axle tie rod away from the rear control arm is hinged to the extension arm two. When the vehicle is turning, the front control arm transmits power to the second axle linkage through the front transition tie rod, middle control arm, rear transition tie rod, rear control arm, and second axle tie rod. The second axle tie rod drives the second axle control arm to rotate, and the second axle long tie rod and second axle short tie rod drive the left steering knuckle arm and right steering knuckle arm to rotate respectively, realizing the synchronous steering operation of the front axle second and front axle first.

[0014] Optionally, the rear control arm has a rear extension arm one, the top of which is hinged to the frame, and the bottom of the rear extension arm one extends downward to be flush with the second axle control arm. One end of the second axle tie rod is hinged to the bottom of the rear extension arm one via a ball joint, and the other end of the second axle tie rod is hinged to the extension arm two via a ball joint. The frame is fixedly mounted with extension frame one and extension frame two extending downward. The front control arm is hinged to extension frame one, and the rear control arm is hinged to extension frame two. The front and rear control arms are located on the front and rear sides of the front axle one, respectively, and are at the same height as the front axle one. The middle control arm is located at the top of the front axle one. Because the rotation axis of the rear control arm is horizontal, the height position of its hinge point with the second axle tie rod will change during rotation. However, the rotation axis of the second axle control arm is vertical, and the height position of the hinge point between the second axle tie rod and the second axle control arm will not change during rotation. This causes the height position of both ends of the second axle tie rod to change during operation. To adapt to this change and avoid jamming, both ends of the second axle tie rod are hinged with ball joints. The front control arm, middle control arm, and rear control arm form an upward-arching triangular structure. The front transition tie rod and the rear transition tie rod can extend from the top around the front axle to the front axle, while also ensuring that the bottom ends of the front control arm and the rear control arm extend to positions flush with the first axle control arm and the second axle control arm, respectively.

[0015] A vehicle employs a dual front axle power steering system as described above. By applying power to both front axles simultaneously through two power steering circuits, it ensures effective power steering under high loads and guarantees emergency power steering in case of a power steering pump failure, thus ensuring driving safety.

[0016] The advantages of the technical solution of this utility model compared with the prior art are as follows:

[0017] Power steering pump one and power steering pump two are connected to the chambers of power steering cylinder one and power steering cylinder two through circuit one and circuit two of the dual-circuit power steering system, respectively. During steering, power steering cylinder one and power steering cylinder two apply steering assistance to front axle one and front axle two, respectively. Compared with the existing method of providing steering assistance to both front axles through a single power steering cylinder, the present invention can provide stronger steering assistance and distribute the assistance more evenly to the two front axles, ensuring steering assistance effect under high load. At the same time, if power steering pump one fails to supply oil, power steering pump two can still ensure steering assistance under light load or non-stationary steering conditions. If power steering pump two fails to supply oil, the emergency pump can take over the position of power steering pump two to provide assistance. In addition, if the vehicle's engine loses power during driving, causing power steering pump one and power steering pump two to stop working, since the emergency pump is driven by gears in the vehicle's power coupling box, and the gears in the vehicle's power coupling box continue to rotate under the vehicle's inertia during coasting, the emergency pump can also work to provide hydraulic oil to the dual-circuit power steering system and power steering cylinder two, ensuring that a certain amount of steering assistance can be provided even during coasting. Furthermore, compared to the prior art which uses a single assist cylinder to apply assistance, this application, with the same total load, can reduce the load on a single assist cylinder by using more assist cylinders, and make the force distribution of the transmission linkage more uniform. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Hydraulic schematic diagram of a dual front axle power steering system;

[0020] Figure 2 This is a schematic diagram of the power structure of an emergency pump;

[0021] Figure 3 Top view of the installation structure of the dual front axle power steering system;

[0022] Figure 4 Hydraulic schematic diagram of a dual front axle power steering system with four sets of power cylinders;

[0023] Figure 5 Top view of the mounting structure of a dual front axle power steering system with four sets of power cylinders;

[0024] Figure 6 This is a tilted view of the transmission structure of front axle one and front axle two.

[0025] Figure 7 This is a diagram of the front axle and steering linkage structure for obstacle avoidance.

[0026] Icons: 11. Dual-circuit power steering; 111. Steering arm; 12. Fuel tank; 13. Engine; 14. Power coupling box; 15. Drive shaft; 21. Power steering pump one; 22. Power steering pump two; 23. Emergency pump; 3. Emergency valve; 41. Power steering cylinder one; 42. Power steering cylinder two; 43. Power steering cylinder three; 44. Power steering cylinder four; 5. Chassis; 51. Front axle one; 511. Axle housing one; 512. Left steering knuckle arm one; 513. Right steering knuckle arm one; 52. Front axle two; 521. Axle housing two; 522. Left steering knuckle arm two; 523. Right steering knuckle arm two; 53. Left frame; 54. Right frame; 55. Mounting plate; 6. Pressure sensor; 701. Tie rod; 702. Front control arm; 703. 704. First Axle Tie Rod; 705. First Axle Swing Arm; 706. First Axle Long Cross Tie Rod; 707. First Axle Short Cross Tie Rod; 708. Front Extension Arm 1; 709. Extension Arm 1; 710. Front Transition Tie Rod; 711. Middle Swing Arm; 712. Rear Transition Tie Rod; 713. Rear Swing Arm; 714. Second Axle Tie Rod; 715. Second Axle Long Cross Tie Rod; 716. Second Axle Short Cross Tie Rod; 717. Extension Arm 2; 718. Rear Extension Arm 1; 719. Extension Frame 1; 720. Extension Frame 2; 721. Front Extension Arm 2; 722. Middle Extension Arm 1; 723. Middle Extension Arm 2; 724. Rear Extension Arm 2; 81. Steering Wheel; 82. Steering Column; 83. Angle Transmission; 84. Rotary Driveshaft. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] Example 1:

[0029] This embodiment provides a dual front axle power steering system. In this embodiment, the direction of the vehicle's front is considered the front side, and the direction of the vehicle's rear is considered the rear side. Based on Figures 1 to 3As shown, the dual front axle power steering system includes a dual-circuit power steering gear 11, an oil tank 12, a power steering pump 1 21, a power steering pump 22, an emergency pump 23, an emergency valve 3, a power steering cylinder 1 41, and a power steering cylinder 2 42. Power steering cylinder 1 41 and power steering cylinder 2 42 are used to assist the two front axles of the vehicle, respectively. Both the dual-circuit power steering gear 11 and the emergency valve 3 utilize existing steering gears and emergency valves. The dual-circuit power steering gear 11 has two circuits: circuit one and circuit two. Circuit one has an oil inlet P1, an oil return port T1, a working oil port A1, and a working oil port B1; circuit two has an oil inlet P2, an oil return port T2, a working oil port A2, and a working oil port B2. The connection status of circuit one and circuit two is controlled by the steering wheel 81. When turning left, working oil port A1 is connected to oil return port T1, working oil port B1 is connected to oil inlet port P1, working oil port A2 is connected to oil return port T2, and working oil port B2 is connected to oil inlet port P2. When turning right, working oil port A1 is connected to oil inlet port P1, working oil port B1 is connected to oil return port T1, working oil port A2 is connected to oil inlet port P2, and working oil port B2 is connected to oil return port T2.

[0030] Emergency valve 3 has an oil inlet P3, an oil inlet P4, a working oil inlet A3, and a return oil inlet T3. Oil inlet P1 is connected to the oil tank 12 via booster pump 21, and return oil inlet T1 is connected to the oil tank 12. Working oil inlets A1 and B1 are connected to the rodless and rod chambers of booster cylinder 41, respectively. Oil inlet P3 is connected to the oil tank 12 via booster pump 22, oil inlet P4 is connected to the oil tank 12 via emergency pump 23, working oil inlet A3 is connected to oil inlet P2, and return oil inlets T3 and T2 are both connected to the oil tank 12. Working oil inlets A2 and B2 are connected to the rodless and rod chambers of booster cylinder 42, respectively. Under normal operation, oil inlet P3 is connected to working oil inlet A3 and oil inlet P4 is connected to return oil inlet T3. When power booster pump 22 malfunctions, oil inlet P4 is connected to working oil inlet A3, while oil inlet P3 and return oil inlet T3 are both blocked. Power booster pump 21 and power booster pump 22 are both driven by the output of the vehicle engine 13, and emergency pump 23 is driven by gears within the vehicle's power coupling box 14.

[0031] based on Figure 2 As shown, the vehicle engine 13 transmits power to the front and rear axles via the power coupling box 14 and drive shaft 15, which is the structure of existing vehicles. Both power steering pump 1 21 and power steering pump 22 are directly driven by the output power take-off port of the vehicle engine 13. When the vehicle engine 13 is turned off, power steering pump 1 21 and power steering pump 22 stop operating synchronously. The power input end of the emergency pump 23 is connected to the gear shaft inside the power coupling box 14. When the vehicle is turned off and coasting due to inertia, the gear inside the power coupling box 14 continues to rotate under the vehicle's inertia, allowing the emergency pump 23 to continue operating even when the vehicle engine 13 is off and coasting.

[0032] In this embodiment, based on Figure 3 and Figure 6 As shown, the system also includes a frame 5 and a steering linkage. A dual-circuit power steering system 11 is mounted on the frame 5. The frame 5 is equipped with a first front axle 51 and a second front axle 52. The first front axle 51 has an axle housing 511 and steering knuckle arms 52 at both ends of the axle housing 511. The second front axle 52 has an axle housing 521 and steering knuckle arms 52 at both ends of the axle housing 521. The output end of the dual-circuit power steering system 11 is connected to the first and second steering knuckle arms via the steering linkage. The dual-circuit power steering system 11 is driven by a steering wheel 81. The power from the steering wheel 81 is transmitted to the input end of the dual-circuit power steering system 11 through a steering column 82, an angle transmission 83, and a rotation drive shaft 84. The cylinder of the first power steering cylinder 41 is hinged to the axle housing 511, and the output end of the first power steering cylinder 41 is hinged to one of the first steering knuckle arms. The cylinder of the second power steering cylinder 42 is hinged to the axle housing 521, and the output end of the second power steering cylinder 42 is hinged to one of the second steering knuckle arms. Specifically, in this embodiment, the two steering knuckle arms are left steering knuckle arm 512 and right steering knuckle arm 513, and the two steering knuckle arms are left steering knuckle arm 522 and right steering knuckle arm 523. The output end of the power steering cylinder 41 is hinged to the left steering knuckle arm 512, and the output end of the power steering cylinder 42 is hinged to the left steering knuckle arm 522. When turning left, power steering cylinders 41 and 42 retract; when turning right, they extend. Of course, depending on the actual situation, the output ends of power steering cylinders 41 and 42 can also be hinged to the right steering knuckle arm 513 and right steering knuckle arm 523, respectively. Correspondingly, during steering, the extension and retraction states of power steering cylinders 41 and 42 are opposite to those in this embodiment; the connection between their rod-side and rodless sides is simply reversed.

[0033] The working process of the dual front axle power steering system in this embodiment is as follows:

[0034] When the vehicle turns left under normal driving conditions, the dual-circuit power steering system 11 switches its working state under the action of the steering wheel 81, connecting the working port A1 with the return port T1, the working port B1 with the inlet port P1, the working port A2 with the return port T2, and the working port B2 with the inlet port P2. Driven by the engine 13, the power steering pump 21 injects hydraulic oil from the oil tank 12 through the inlet port P1 and the working port B1 into the rod chamber of the power steering cylinder 41. The hydraulic oil in the rodless chamber of the power steering cylinder 41 flows back to the oil tank 12 through the working port A1 and the return port T1. The power steering cylinder 41 contracts, causing the front axle 51 to turn left. Driven by the engine 13, the power steering pump 22 injects hydraulic oil from the oil tank 12 through the oil inlet P3, working oil port A3, oil inlet P2 and working oil port B2 into the rod chamber of the power steering cylinder 42. The hydraulic oil in the rodless chamber of the power steering cylinder 42 flows back to the oil tank 12 through the working oil port A2 and the return oil port T2. The power steering cylinder 42 contracts, driving the front axle 52 to turn left, thus achieving left-turn steering assistance.

[0035] When the vehicle turns right under normal driving conditions, the dual-circuit power steering system 11 switches its working state under the action of the steering wheel 81. The working port A1 is connected to the inlet port P1, the working port B1 is connected to the return port T1, the working port A2 is connected to the inlet port P2, and the working port B2 is connected to the return port T2. Driven by the engine 13, the power steering pump 21 injects hydraulic oil from the oil tank 12 through the inlet port P1 and the working port A1 into the rodless chamber of the power steering cylinder 41. The hydraulic oil in the rod chamber of the power steering cylinder 41 flows back to the oil tank 12 through the working port B1 and the return port T1. The power steering cylinder 41 extends, driving the front axle 51 to turn to the right. Driven by engine 13, power steering pump 22 injects hydraulic oil from oil tank 12 through inlet P3, working port A3, inlet P2 and working port A2 into the rodless chamber of power steering cylinder 42. The hydraulic oil in the rod chamber of power steering cylinder 42 flows back to oil tank 12 through working port B2 and return port T2. Power steering cylinder 42 extends, driving front axle 52 to turn right, thus achieving right steering assistance.

[0036] Emergency valve 3 internally comprises a two-position four-way valve core, a two-position two-way valve core, and an oil inlet throttling orifice connected in parallel with the two-position four-way valve core. The two oil inlets of the two-position four-way valve core are connected to oil inlet P3 and oil inlet P4 respectively. One oil outlet of the two-position four-way valve core is connected to working oil port A3, and the other oil outlet is connected to the oil inlet of the two-position two-way valve core. The oil outlet of the two-position two-way valve core is connected to return oil port T3. An indicator light switch is installed at the two-position two-way valve core. During operation, emergency valve 3 monitors the flow rate at inlet P3 in real time. When power booster pump 22 is working normally, the actual flow rate at inlet P3 is greater than the set value. The pressure difference across the inlet throttle orifice in emergency valve 3 is large. Under the action of this pressure difference, the spring on one side of the two-position four-way valve core in emergency valve 3 is compressed, making inlet P3 connected to working port A3. The hydraulic oil discharged from emergency pump 23 flows from inlet P4, through the two-position four-way valve core and the two-position two-way valve core in emergency valve 3, and connects to return port T3. A certain pressure is generated in the throttle orifice of the two-position two-way valve core. This pressure is greater than the spring force, causing the two-position two-way valve core to move. The indicator light switch of emergency valve 3 is turned off, and the indicator light is turned off. When power booster pump 22 loses power due to a malfunction, the flow rate at inlet P3 decreases. Emergency valve 3 detects that the flow rate at inlet P3 has fallen below the set value. The pressure difference across the inlet throttle orifice of emergency valve 3 decreases. This pressure difference is insufficient to overcome the spring force on one side of the two-position four-way valve. The two-position four-way valve remains in its initial state, connecting inlet P4 to working port A3. Both inlet P3 and return port T3 are blocked. No flow passes through the throttle orifice of the two-position two-way valve, maintaining its initial state. The indicator light switch closes, and the indicator light illuminates to alert the driver. At this time, emergency pump 23 pumps oil from tank 12 into inlet P1 through inlet P4 and working port A3 to take over the operation of power booster pump 22.

[0037] When power steering pump 21 loses power due to a malfunction, since power steering cylinders 41 and 42 provide steering assistance to front axle 51 and 52 respectively, even if power steering cylinder 41 cannot provide assistance to front axle 51, power steering pump 22 can still provide some assistance to front axle 52, preventing all assistance from failing. Furthermore, when front axle 52 turns, it can also provide some steering assistance to front axle 51 through the steering linkage, ensuring the vehicle can turn normally and ensuring safety. In this embodiment, a pressure sensor 6 is installed between the return port T1 and the fuel tank 12. When power steering pump 21 fails to supply fuel, although power steering cylinder 42 can still provide some assistance, the reduced assistance affects steering operation. At this time, the return pressure at return port T1 will be lower than the set value, and pressure sensor 6 will send a signal to the vehicle control system to issue an alarm, reminding the driver and improving the safety of the steering system.

[0038] If engine 13 suddenly stalls during driving, the vehicle will coast due to inertia. At this time, power steering pump 1 21 and power steering pump 22 simultaneously lose power, and the flow and pressure at oil inlet P3 decrease. Emergency valve 3 detects the decrease in flow at oil inlet P3, and the two-position four-way valve core of emergency valve 3 automatically switches its state under the action of the spring, connecting oil inlet P4 with working oil port A3, while oil inlet P3 and return oil port T3 are both blocked. During the coasting process, the gears in the power coupling box 14 rotate under inertia, and emergency pump 23 continues to operate. Emergency pump 23 can pump oil from oil tank 12 into oil inlet P1 through oil inlet P4 and working oil port A3, providing steering assistance to front axle 1 51 and front axle 2 52 through the linkage driven by the output shaft of dual-circuit power steering gear 11 and power steering cylinder 2 42, thus preventing the complete failure of power steering.

[0039] Furthermore, based on Figure 3 and Figure 6 As shown, the frame 5 in this embodiment has a left main beam 53 and a right main beam 54, which are connected by a certain number of crossbeams to form a frame structure. The dual-circuit power steering 11 is fixedly connected to the frame 5 in a prone position. Specifically, a mounting plate 55 is fixed between the left main beam 53 and the right main beam 54, and the dual-circuit power steering 11 is fixed on the mounting plate 55. The prone position means that the output end of the dual-circuit power steering 11 extends vertically to the bottom, and the output end of the dual-circuit power steering 11 has a steering rocker arm 111. The steering linkage includes a longitudinal tie rod 701, a front control arm 702, a primary axle tie rod 703, and a primary axle linkage located at the bottom of the front axle 51. The axle linkage includes an axle control arm 704, a long tie rod 705, and a short tie rod 706. The axle control arm 704 is hinged to the bottom of the axle housing 511. The axle control arm 704, the left steering knuckle arm 512, and the right steering knuckle arm 513 all extend towards the rear of the frame 5. The axle control arm 704 also has an extension arm 708 parallel to the axle housing 511. The two ends of the long tie rod 705 are hinged to the axle control arm 704 and the left steering knuckle arm 512, respectively. The two ends of the short tie rod 706 are hinged to the axle control arm 704 and the right steering knuckle arm 513, respectively. The front control arm 702 is located between the dual-circuit power steering unit 11 and the front axle 51. The front control arm 702 is hinged to the frame 5. The two ends of the longitudinal tie rod 701 are hinged to the steering rocker arm 111 and the front control arm 702, respectively. The two ends of the axle tie rod 703 are hinged to the front control arm 702 and the extension arm 708, respectively.

[0040] When the vehicle is turning, the output end of the dual-circuit power steering 11 drives the steering rocker arm 111 to rotate. The steering rocker arm 111 drives the front control arm 702 to rotate via the longitudinal tie rod 701. The front control arm 702 drives the first axle control arm 704 to rotate along the axle housing 511 via the first axle tie rod 703. When the first axle control arm 704 rotates, it drives the left steering knuckle arm 512 and the right steering knuckle arm 513 to rotate via the first axle long lateral tie rod 705 and the first axle short lateral tie rod 706, respectively, thereby realizing the steering operation of the front axle 51.

[0041] Preferably, the front control arm 702 has a front extension arm 707, the top of which is hinged to the frame 5, and the bottom of the front extension arm 707 extends downward to be flush with the first axle control arm 704. One end of the longitudinal tie rod 701 is hinged to the steering rocker arm 111 via a ball joint, and the other end of the longitudinal tie rod 701 is hinged to the middle of the front extension arm 707 via a ball joint. One end of the first axle tie rod 703 is hinged to the bottom of the front extension arm 707 via a ball joint, and the other end of the first axle tie rod 703 is hinged to the extension arm 708 via a ball joint. It should be noted that the bottom of the front extension arm 707 extending downward to be flush with the first axle control arm 704 does not mean there is no height difference at all, but rather that they are roughly at the same height. The axle tie rod can extend to the bottom of the front axle 51 via the bottom-extending front extension arm 707 to transmit power from the bottom of the front axle 51 to the axle linkage. At this point, the first axle tie rod 703 can be roughly in a horizontal position. The output end of the dual-circuit power steering system 11, which extends vertically downwards, minimizes the length of the longitudinal tie rod 701 and the first axle tie rod 703 that drive the front axle 51, reducing the transmission path length. The front control arm 702 is specifically hinged to the right main beam 54 on the side facing the left main beam 53. When the front control arm 702 rotates, the height of its hinge points with the longitudinal tie rod 701 and the first axle tie rod 703 changes during rotation. The output shaft axis of the dual-circuit power steering 11 and the rotation axis of the first-axle swing arm 704 are both set vertically. The height position of the hinge between the longitudinal tie rod 701 and the steering rocker arm 111, and the hinge between the first-axle tie rod 703 and the first-axle swing arm 704 does not change during rotation. This means that the height position of the two ends of the longitudinal tie rod 701 and the two ends of the first-axle tie rod 703 will change during operation. In order to adapt to this change and avoid jamming, the two ends of the longitudinal tie rod 701 and the two ends of the first-axle tie rod 703 are all ball joints.

[0042] based on Figure 3 and Figure 6As shown, the steering linkage also includes a second axle linkage located at the bottom of the front axle 52, and a front transition tie rod 709, a middle control arm 710, a rear transition tie rod 711, a rear control arm 712, and a second axle tie rod 713 sequentially hinged from the front control arm 702 toward the rear side of the frame 5. The middle control arm 710 and the rear control arm 712 are both hinged to the frame 5, specifically to the side of the right main beam 54 facing the left main beam 53. The second axle linkage includes a second axle control arm 714, a second axle long tie rod 715, and a second axle short tie rod 716. The second axle control arm 714 is hinged to the bottom of the axle housing 521. The second axle control arm 714, the left steering knuckle arm 522, and the right steering knuckle arm 523 all extend toward the rear side of the frame 5. The second axle control arm 714 also has an extension arm 717 parallel to the axle housing 521. The two ends of the second axle long cross tie rod 715 are respectively hinged to the second axle swing arm 714 and the left steering knuckle arm 522. The two ends of the second axle short cross tie rod 716 are respectively hinged to the second axle swing arm 714 and the right steering knuckle arm 523. The end of the second axle tie rod 713 away from the rear swing arm 712 is hinged to the extension arm 717.

[0043] When the vehicle is turning, the front control arm 702 drives the front axle 51 to rotate via the first axle tie rod 703 and the first axle linkage. Simultaneously, the front control arm 702 transmits power to the second axle linkage through the front transition tie rod 709, the middle control arm 710, the rear transition tie rod 711, the rear control arm 712, and the second axle tie rod 713. The second axle tie rod 713 drives the first axle control arm 704 to rotate, and the second axle long lateral tie rod 715 and the second axle short lateral tie rod 716 drive the left steering knuckle arm 522 and the right steering knuckle arm 523 to rotate, respectively, achieving synchronous steering operation between the front axle 52 and the front axle 51.

[0044] Preferably, based on Figure 3 , Figure 6 and Figure 7 As shown, the rear control arm 712 has a rear extension arm 718. The top of the rear control arm 712 is hinged to the frame 5, and the bottom end of the rear extension arm 718 extends downward to be flush with the second axle control arm 714. One end of the second axle tie rod 713 is hinged to the bottom end of the rear extension arm 718 via a ball joint, and the other end of the second axle tie rod 713 is hinged to the extension arm 717 via a ball joint. Similarly, the bottom end of the rear extension arm 718 extends downward to be flush with the second axle control arm 714. "Flat" does not mean there is no height difference, but rather that they are roughly at the same height. At this time, the second axle tie rod 713 can be roughly horizontal. Also, since the rotation axis of the rear control arm 712 is horizontal, the height position of its hinge point with the second axle tie rod 713 will change during rotation. The rotation axis of the second bridge swing arm 714 is set vertically. The height position of the hinge between the second bridge tie rod 713 and the second bridge swing arm 714 does not change during rotation. This means that the height position of both ends of the second bridge tie rod 713 will change during operation. In order to adapt to this change and avoid jamming, both ends of the second bridge tie rod 713 are ball joints.

[0045] Preferably, the frame 5 is fixedly equipped with an extension frame 719 extending downwards and an extension frame 720. The front control arm 702 is hinged to the extension frame 719, and the rear control arm 712 is hinged to the extension frame 720. The front control arm 702 and the rear control arm 712 are located on the front and rear sides of the front axle 51 respectively and are at the same height as the front axle 51. The middle control arm 710 is located at the top of the front axle 51. In this way, the front control arm 702, the middle control arm 710, and the rear control arm 712 form an upwardly arched triangular structure. The front transition rod 709 and the rear transition rod 711 can pass around the front axle 51 from the top and extend to the front axle 52. At the same time, it can also ensure that the bottom ends of the front control arm 702 and the rear control arm 712 extend to positions flush with the first axle control arm 704 and the second axle control arm 714 respectively. In this embodiment, the front swing arm 702 is further provided with a downwardly extending front extension arm 721, the middle swing arm 710 is provided with an upwardly extending middle extension arm 722 and a middle extension arm 723, and the rear swing arm 712 is further provided with a downwardly extending rear extension arm 724. The two ends of the front transition rod 709 are hinged to the front extension arm 721 and the middle extension arm 722, respectively, and the rear transition rod 711 is hinged to the middle extension arm 723 and the rear extension arm 724, respectively, thus achieving hinged connections between the front swing arm 702 and the second axle tie rod 713.

[0046] Example 2:

[0047] This embodiment provides a dual front axle power steering system, specifically, based on embodiment 1, it further includes power steering cylinder 3 43. Figure 1 and Figure 3 As shown, the rodless chamber of power steering cylinder 3 43 is connected to the working oil port B1, and the rod chamber of power steering cylinder 3 43 is connected to the working oil port A1. The steering knuckle arms 1 located at both ends of axle housing 1 511 are the left steering knuckle arm 1 512 and the right steering knuckle arm 1 513, respectively. The steering knuckle arms 2 located at both ends of axle housing 2 521 are the left steering knuckle arm 2 522 and the right steering knuckle arm 2 523, respectively. Power steering cylinder 1 41 and power steering cylinder 2 42 are located on the same side of the frame 5. The output end of power steering cylinder 1 41 is hinged to the left steering knuckle arm 1 512, the output end of power steering cylinder 2 42 is hinged to the left steering knuckle arm 2 522, the cylinder barrel of power steering cylinder 3 43 is hinged to axle housing 2 521, and the output end of power steering cylinder 3 43 is hinged to the right steering knuckle arm 2 523.

[0048] With the above configuration, this embodiment provides one power steering cylinder at front axle 51 and two power steering cylinders at front axle 52. Compared to the two power steering cylinders in embodiment 1, this provides greater power assistance and is suitable for vehicles with higher loads. Power steering cylinder 41 and power steering cylinder 43 are connected in parallel, both driven by power steering pump 21 and connected to circuit one of the dual-circuit power steering system 11. That is, power steering pump 21 simultaneously provides the hydraulic pressure needed for power steering to both front axle 51 and front axle 52. When power steering pump 21 fails, the hydraulic pressure in circuit one drops, and the return pressure at return port T1 falls below the set value. Pressure sensor 6 sends a signal to the vehicle control system to issue an alarm to remind the driver. Meanwhile, since power steering pump 22 still functions normally, it provides steering assistance to both front axle 51 and front axle 52 through the linkage driven by the output shaft of the dual-circuit power steering system 11 and power steering cylinder 42, ensuring the vehicle can steer normally and ensuring safety.

[0049] Example 3:

[0050] This embodiment provides a dual front axle power steering system, specifically, based on embodiment 2, it further includes power steering cylinder 44. Figure 4 and Figure 5 As shown, the rod-side chamber of power steering cylinder 44 is connected to the working oil port A2, and the rodless chamber of power steering cylinder 44 is connected to the working oil port B2. The cylinder barrel of power steering cylinder 44 is hinged to axle housing 511, and the output end of power steering cylinder 44 is hinged to the right steering knuckle arm 513. With the above configuration, this embodiment has two power steering cylinders at front axle 51 and two power steering cylinders at front axle 52. Compared to the two power steering cylinders in embodiment 1 and the three power steering cylinders in embodiment 3, it can provide greater power assistance and is suitable for vehicles with higher loads.

[0051] In this embodiment, power steering cylinder 41 and power steering cylinder 43 are connected in parallel. Both are driven by power steering pump 21 and connected to circuit one of the dual-circuit power steering system 11. Power steering pump 21 provides hydraulic pressure for power steering to both front axle 51 and front axle 52. Simultaneously, power steering cylinder 42 and power steering cylinder 44 are connected in parallel. Both are driven by power steering pump 22 and connected to circuit two of the dual-circuit power steering system 11. Power steering pump 22 also provides hydraulic pressure for power steering to both front axle 51 and front axle 52. When power steering pump 21 fails, power steering pump 22 can still provide partial power steering to both front axle 51 and front axle 52 simultaneously. When power steering pump 22 fails, emergency pump 23 takes over from power steering pump 22 and provides partial power steering to both front axle 51 and front axle 52 simultaneously, ensuring balanced force distribution on both axles.

[0052] Example 4:

[0053] This embodiment provides a vehicle employing a dual front axle power steering system as shown in any one of embodiments 1-3. During steering, power steering cylinder 1 41 and power steering cylinder 2 42 apply steering assistance to front axle 1 51 and front axle 2 52. Compared to existing systems that provide steering assistance to both front axles through a single power steering cylinder, this invention provides stronger steering assistance and distributes the assistance more evenly between the two front axles, ensuring effective steering assistance under high loads. Furthermore, if power steering pump 1 21 malfunctions and cannot supply oil, power steering pump 2 22 can still ensure steering assistance under light loads or when steering out of place. If power steering pump 2 22 malfunctions and cannot supply oil, emergency pump 23 can take over the position of power steering pump 1 21 to provide assistance. If the vehicle's engine 13 loses power during driving, causing power steering pump 1 21 and power steering pump 22 to stop working, the emergency pump 23 is driven by gears in the vehicle's power coupling box 14. Since the gears in the vehicle's power coupling box 14 continue to rotate due to inertia during the vehicle's coasting, the emergency pump 23 can also work to provide hydraulic oil to the dual-circuit power steering system 11 and power steering cylinder 2 42, ensuring that a certain amount of steering assistance can be provided during coasting.

[0054] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A dual front axle power steering system, characterized in that: The system includes a dual-circuit power steering system, an oil tank, a power steering pump I, a power steering pump II, an emergency pump, an emergency valve, a power steering cylinder I, and a power steering cylinder II. Power steering cylinder I and power steering cylinder II are used to assist the two front axles of the vehicle, respectively. The dual-circuit power steering system has a first circuit and a second circuit. The first circuit has an oil inlet P1, an oil return port T1, a working oil port A1, and a working oil port B1. The second circuit has an oil inlet P2, an oil return port T2, a working oil port A2, and a working oil port B2. The emergency valve has an oil inlet P3, an oil inlet P4, a working oil port A3, and an oil return port T3. The oil inlet P1 is connected to the oil tank via the first power-assisted pump, and the oil return port T1 is connected to the oil tank. The working oil inlet A1 and the working oil inlet B1 are respectively connected to the rodless chamber and the rod chamber of the first power-assisted cylinder. The oil inlet P3 is connected to the oil tank via the second power-assisted pump, and the oil inlet P4 is connected to the oil tank via the emergency pump. The working oil inlet A3 is connected to the oil inlet P2. The oil return ports T3 and T2 are both connected to the oil tank. The working oil inlet A2 and the working oil inlet B2 are respectively connected to the rodless chamber and the rod chamber of the second power-assisted cylinder. During normal operation, the oil inlet P3 is connected to the working oil inlet A3 and the oil inlet P4 is connected to the return oil inlet T3. When the power booster pump 2 is in a faulty state, the oil inlet P4 is connected to the working oil inlet A3, and both the oil inlet P3 and the return oil inlet T3 are blocked. Both the power booster pump 1 and the power booster pump 2 are driven by the output end of the vehicle engine, and the emergency pump is driven by gears in the vehicle power coupling box.

2. The dual front axle power steering system as described in claim 1, characterized in that: It also includes a frame and a steering linkage. The dual-circuit power steering is mounted on the frame. The frame is equipped with a front axle one and a front axle two. The front axle one has an axle housing one and steering knuckle arms one located at both ends of the axle housing one. The front axle two has an axle housing two and steering knuckle arms two located at both ends of the axle housing two. The output end of the dual-circuit power steering is connected to the steering knuckle arms one and the steering knuckle arms two through the steering linkage. The cylinder barrel of the first power steering cylinder is hinged to the first axle housing, and the output end of the first power steering cylinder is hinged to one of the first steering knuckle arms. The cylinder barrel of the second power steering cylinder is hinged to the second axle housing, and the output end of the second power steering cylinder is hinged to one of the second steering knuckle arms.

3. The dual front axle power steering system as described in claim 2, characterized in that: It also includes a third power steering cylinder, the rodless chamber of which is connected to the working oil port B1, and the rod chamber of which is connected to the working oil port A1; the first steering knuckle arms located at both ends of the first axle housing are the left steering knuckle arm and the right steering knuckle arm, respectively; the second steering knuckle arms located at both ends of the second axle housing are the left steering knuckle arm and the right steering knuckle arm, respectively; the first and second power steering cylinders are located on the same side of the frame; the output end of the first power steering cylinder is hinged to the first left steering knuckle arm; the output end of the second power steering cylinder is hinged to the second left steering knuckle arm; the cylinder of the third power steering cylinder is hinged to the second axle housing; and the output end of the third power steering cylinder is hinged to the second right steering knuckle arm.

4. The dual front axle power steering system as described in claim 3, characterized in that: It also includes a power steering cylinder four, the rod chamber of which is connected to the working oil port A2, and the rodless chamber of which is connected to the working oil port B2; the cylinder barrel of the power steering cylinder four is hinged to the axle housing, and the output end of the power steering cylinder four is hinged to the right steering knuckle arm.

5. The dual front axle power steering system as described in any one of claims 1-4, characterized in that: A pressure sensor is installed between the oil return port T1 and the oil tank.

6. The dual front axle power steering system as described in claim 3, characterized in that: The dual-circuit power steering system is fixedly connected to the vehicle frame in a prone position. The output end of the dual-circuit power steering system extends vertically to the bottom and has a steering rocker arm. The steering linkage system includes a longitudinal tie rod, a front control arm, a first axle tie rod, and a first axle linkage system located at the bottom of the front axle. The first axle linkage system includes a first axle control arm, a first axle long lateral tie rod, and a first axle short lateral tie rod. The first axle control arm is hinged to the bottom of the axle housing. The first axle control arm, the left steering knuckle arm, and the right steering knuckle arm all extend toward the rear of the vehicle frame. The first axle control arm also has an extension arm parallel to the axle housing. The two ends of the long lateral tie rod of the first axle are respectively hinged to the first axle swing arm and the left steering knuckle arm. The two ends of the short lateral tie rod of the first axle are respectively hinged to the first axle swing arm and the right steering knuckle arm. The front swing arm is located between the dual-circuit power steering and the first front axle. The front swing arm is hinged to the vehicle frame. The two ends of the longitudinal tie rod are respectively hinged to the steering rocker arm and the front swing arm. The two ends of the first axle tie rod are respectively hinged to the front swing arm and the extension arm.

7. The dual front axle power steering system as described in claim 6, characterized in that: The front control arm has a front extension arm, the top end of which is hinged to the vehicle frame, and the bottom end of the front extension arm extends downward to be flush with the first axle control arm. One end of the longitudinal tie rod is hinged to the steering rocker arm via a ball joint, and the other end of the longitudinal tie rod is hinged to the middle of the front extension arm via a ball joint. One end of the first axle tie rod is hinged to the bottom end of the front extension arm via a ball joint, and the other end of the first axle tie rod is hinged to the extension arm via a ball joint.

8. The dual front axle power steering system as described in claim 7, characterized in that: The steering linkage also includes a second axle linkage located at the bottom end of the second front axle, and a front transition tie rod, a middle control arm, a rear transition tie rod, a rear control arm, and a second axle tie rod sequentially hinged from the front control arm toward the rear side of the frame. The middle control arm and the rear control arm are both hinged to the frame. The second axle linkage includes a second axle control arm, a second axle long tie rod, and a second axle short tie rod. The second axle control arm is hinged to the bottom of the second axle housing. The second axle control arm, the second left steering knuckle arm, and the second right steering knuckle arm all extend toward the rear side of the frame. The second axle control arm also has an extension arm parallel to the second axle housing. The two ends of the long cross brace of the second axle are respectively hinged to the second axle swing arm and the left steering knuckle arm. The two ends of the short cross brace of the second axle are respectively hinged to the second axle swing arm and the right steering knuckle arm. The end of the second axle brace away from the rear swing arm is hinged to the extension arm.

9. The dual front axle power steering system as described in claim 8, characterized in that: The rear swing arm has a rear extension arm one, the top end of the rear swing arm is hinged to the frame, the bottom end of the rear extension arm one extends downward to be flush with the second axle swing arm, one end of the second axle tie rod is hinged to the bottom end of the rear extension arm one by a ball joint, and the other end of the second axle tie rod is hinged to the extension arm two by a ball joint. The vehicle frame is fixedly equipped with an extension frame 1 and an extension frame 2 extending to the bottom. The front swing arm is hinged to the extension frame 1, and the rear swing arm is hinged to the extension frame 2. The front swing arm and the rear swing arm are located on the front and rear sides of the front axle 1 respectively and are at the same height as the front axle 1. The middle swing arm is located on the top of the front axle 1.

10. A vehicle, characterized in that: The dual front axle power steering system as described in any one of claims 1-9 is employed.

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