Vehicle suspension system capable of being accurately folded, unfolded and positioned

Abstract

The invention discloses a vehicle suspension system capable of being accurately folded, unfolded and positioned. The system comprises an executing mechanism, a suspension assembly and a flow control module. The executing mechanism comprises a pull arm, a longitudinal arm assembly and a bearing wheel; the bearing wheel is mounted at the tail end of the longitudinal arm assembly and can rotate flexibly; the head end of the longitudinal arm assembly is fixedly installed on a hinge shaft, and the hinge shaft is installed on a vehicle body and can pivot. One end of the pull arm is fixedly connected with the hinge shaft; and an angle is formed between the pull arm and the longitudinal arm assembly. The suspension assembly is used for adjusting the trailing arm, and the flow control module accumulates pressure for a pressure accumulator of the suspension assembly. While different vehicle height requirements of land and water running working conditions are met, the height limit index can be met by accurately reducing the suspension height, namely, the bearing capacity of the vehicle is improved to the maximum extent while the index requirements are met through the suspension system. The device also has the advantages of simple structure, high reliability and good maintainability.

Description

Technical Field

[0001] The invention relates to a vehicle suspension system which can be accurately retracted and positioned. Background Art

[0002] Vehicle suspension is an important system of the vehicle. It ensures that the vehicle has sufficient height from the ground during driving, and has the function of attenuating and transforming vehicle vibration. It realizes the retractable function for special vehicles, and at the same time ensures that the vehicle does not exceed the height limit and does not drag when boarding the landing ship. At present, the suspension of civilian vehicles is basically in the form of a cross arm plus a shock absorber, which cannot meet the needs of adjusting the vehicle posture. The torsion bar suspension used in most special vehicles ensures that the height of the vehicle body from the ground is a fixed value, which can basically not be adjusted again. Although the oil and gas suspension used in amphibious special vehicles can realize the retractable function, it cannot be accurately positioned at any specified height from the ground. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a suspension system with simple structure, high reliability and good maintainability, which can meet the requirements of special vehicles with different vehicle heights when traveling on land, improve the vehicle's ground obstacle crossing ability and can accurately retract and position over aerial obstacles with height restrictions.

[0004] The technical solution adopted by the present invention is: a vehicle suspension system capable of accurate retraction and positioning, comprising an actuator, a suspension assembly, and a flow control module; The actuator includes a pulling arm, a longitudinal arm assembly and a load-bearing wheel; the load-bearing wheel is installed at the rear end of the longitudinal arm assembly, and the load-bearing wheel can rotate flexibly; the head end of the longitudinal arm assembly is fixedly installed on the articulated shaft, the articulated shaft is installed on the vehicle body, and the articulated shaft can pivot; one end of the pulling arm is fixedly connected to the articulated shaft; there is an angle between the pulling arm and the longitudinal arm assembly; The suspension assembly comprises a power telescopic cylinder, an S-shaped oil pipe and an air pipe; one end of the power telescopic cylinder is hinged to the vehicle body, and the other end is hinged to the pulling arm, and the accumulator is fixed to the vehicle body; the high-pressure oil port of the accumulator is connected to the high-pressure oil port of the power telescopic cylinder through the S-shaped oil pipe, so as to ensure that the oil can flow between the rodless cavity of the power telescopic cylinder and the high-pressure oil cavity of the accumulator; one end of the air pipe is connected to the high-pressure air port of the power telescopic cylinder, and the other end is connected to the compressed air system of the vehicle, so as to ensure that the high-pressure air can flow between the rod cavity of the power telescopic cylinder; The flow control module is connected to the accumulator and can store pressure for the accumulator.

[0005] Furthermore, the accumulator comprises an accumulator barrel, an oil-gas separation piston, an air charging valve, a ball valve, a push rod, a control piston and a valve body; the air charging valve and the valve body are respectively installed at both ends of the accumulator barrel; the oil-gas separation piston is placed in the accumulator barrel and can slide in the inner cavity of the accumulator barrel, the cavity between the oil-gas separation piston and the air charging valve is a nitrogen cavity, and the cavity between the oil-gas separation piston and the valve body is a high-pressure oil cavity; The side wall of the valve body is provided with a locking oil port, an oil inlet and return port, and a high-pressure oil port; a ball valve is provided in the center hole of the valve body, and the ball valve includes a valve seat, a valve sleeve, a ball, and a spring; the valve seat includes a small diameter portion and a large diameter portion, and the small diameter portion is located between the large diameter portion and the accumulator cylinder; the small diameter portion is placed in the center hole of the valve sleeve, and a sealing ring II is provided between the small diameter portion and the center hole of the valve sleeve; the large diameter portion of the valve seat and the valve sleeve are installed in the center hole of the valve body, and a sealing ring I is provided between the large diameter portion, the valve sleeve, and the center hole of the valve body; The center hole of the valve seat is a stepped hole, and a ball is arranged on the stepped surface, which can seal the center hole of the valve seat. A pressure plate is arranged at the end of the center hole of the valve seat, and a hole connected to the center hole of the valve seat is arranged on the pressure plate. A spring is arranged between the ball and the pressure plate, and the spring pressure presses the ball tightly on the stepped surface of the center hole of the valve seat. A radial through hole connected to the center hole of the valve seat is arranged on the small diameter part, and the radial through hole is located between the ball and the large diameter part. The high-pressure oil port is arranged close to the accumulator cylinder, the high-pressure oil port is connected to the center hole of the valve sleeve, and the valve seat can block the high-pressure oil port. A control oil cylinder is provided at the end of the valve body away from the accumulator cylinder, a control oil port is provided on the control oil cylinder, and a control piston is provided in the control oil cylinder; the piston rod end of the control piston extends into the central hole of the valve seat; the locking oil port is connected to the cavity between the control oil cylinder and the valve seat; the oil inlet and return ports are set corresponding to the gap between the large diameter part and the valve sleeve.

[0006] Furthermore, it also includes a cooling fixing sleeve; the cooling fixing sleeve is installed on the vehicle body, the accumulator cylinder is fixed in the cooling fixing sleeve cavity, the accumulator cylinder and the cooling fixing sleeve form a certain cavity, and after the cavity is filled with coolant, a cooling cavity is formed to transfer the oil heat caused by vibration to the vehicle body.

[0007] Furthermore, the flow control module includes a cut-off solenoid valve, a flow meter, a control valve group, a locking accumulator and a locking oil pipe (308); the oil ports at both ends are respectively connected to the oil inlet and return ports of the accumulator through pipelines to the oil supply port of the control valve group, and a cut-off solenoid valve and a flow meter are provided on the pipeline. The cut-off solenoid valve is located between the flow meter and the accumulator, and the cut-off solenoid valve, the control valve group and the locking accumulator are fixed on the vehicle body; the locking oil port of the locking accumulator is connected to the locking oil port of the accumulator through a locking oil pipe; the control oil port is connected to the control oil outlet of the control valve group through the control oil pipe.

[0008] Further, the control valve group includes a retractable reversing valve, a diverter valve, a main oil supply pipe, a main oil return pipe, a locking oil supply pipe, a locking oil return pipe and a locking reversing valve; The oil inlet of the diverter valve is fixedly connected to the main oil supply pipe, and the two diverter ports of the diverter valve are respectively connected to the oil inlets of the retractable reversing valve and the locking reversing valve. The diverter valve, the retractable reversing valve and the locking reversing valve are installed and fixed on the vehicle body; the retractable reversing valve and the locking reversing valve are three-position four-way reversing valves; the two oil outlets of the locking reversing valve are respectively connected to the oil inlet and the oil return port of the locking accumulator through the locking oil supply pipe and the locking oil return pipe; the two oil outlets of the retractable reversing valve are respectively the oil supply port and the control oil outlet of the control valve group.

[0009] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is used to meet the requirements of special vehicles with different vehicle heights when traveling on land. The amount of hydraulic oil charged and discharged into the oil cylinder is accurately calculated under the pulse of the hydraulic oil flow meter, thereby improving the vehicle's ability to overcome ground obstacles and air obstacles with height restrictions.

[0010] 2. When the present invention is used on special vehicles, while meeting the different vehicle height requirements under land conditions, the height limit of the boarding door can be met by accurately lowering the suspension height when landing on a ship on water. The suspension system of the present invention can achieve the index requirements while greatly improving the vehicle's carrying capacity.

[0011] 3. The present invention is applicable not only to tracked vehicles but also to wheeled vehicles and to situations with different numbers of wheel trains; it has good adaptability.

[0012] 4. The present invention also has the advantages of simple device structure, high reliability and good maintainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0014] Figure 2 It is a schematic diagram of the actuator of the present invention on the vehicle body.

[0015] Figure 3 It is a schematic diagram of the actuator of the present invention after the vehicle body is hidden.

[0016] Figure 4 It is a schematic diagram of a suspension assembly of the present invention.

[0017] Figure 5 It is a schematic diagram of the structure of the pressure accumulator of the present invention.

[0018] Figure 6 yes Figure 5 Enlarged view of point I in the middle.

[0019] Figure 7 Schematic diagram of a flow control module of the present invention.

[0020] Figure 8Schematic diagram of the control valve group of the present invention.

[0021] In the figure: 1: actuator; 2: suspension assembly; 3: flow control module; 101: vehicle body; 102: pulling arm; 103: right side plate; 104: load-bearing wheel; 201: support sleeve; 202: power telescopic cylinder; 203: S-type oil pipe; 204: accumulator; 205: air pipe; 20401: fixing sleeve; 20402: accumulator cylinder; 20403: oil-gas separation piston; 20405: ball valve; 20406: push rod; 20407: control piston; 20408: Valve body; 301: connecting pipe I; 302: cut-off solenoid valve; 303: connecting pipe II; 304: flow meter; 305: connecting pipe III; 306: control valve group; 307: locking accumulator; 308: locking oil pipe; 30601: control oil pipe; 30602: retractable reversing valve; 30603: diverter valve; 30604: main oil supply pipe; 30609: main oil return pipe; 30607: locking oil supply pipe; 30609: locking oil return pipe; 30605: locking reversing valve. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and implementation modes.

[0023] like Figure 1 A vehicle suspension system that can be accurately retracted and positioned includes an actuator 1, a suspension component 2, and a flow control module 3.

[0024] like Figure 2-3 The actuator 1 further includes a vehicle body 101, a pulling arm 102, a longitudinal arm assembly 103 and a load-bearing wheel 104. The load-bearing wheel 104 is mounted on the rear end of the longitudinal arm assembly 103 and can rotate flexibly. The front end of the longitudinal arm assembly 103 is fixedly mounted on a hinge shaft, which is mounted on the vehicle body and can pivot. One end of the pulling arm 102 is fixedly connected to the hinge shaft; there is an angle between the pulling arm 102 and the longitudinal arm assembly 103.

[0025] The suspension assembly 2 includes a support sleeve 201, a power telescopic cylinder 202, an S-shaped oil pipe 203 and an air pipe 205; the support sleeve 201 is fixedly mounted on the frame, one end of the power telescopic cylinder 202 is hinged to the support sleeve 201, and the other end is hinged to the pulling arm 102, which can rotate around the support sleeve 201 during the telescopic process, and can drive the pulling arm 102 to rotate around the hinge axis between it and the vehicle body. The accumulator 204 is fixed on the vehicle body 101; the high-pressure oil port of the accumulator 204 is connected to the high-pressure oil port of the power telescopic cylinder 202 through the S-shaped oil pipe 203, ensuring that the oil can flow between the rodless cavity of the power telescopic cylinder 202 and the high-pressure oil cavity of the accumulator 204; one end of the air pipe 205 is connected to the high-pressure air port of the power telescopic cylinder 202, and the other end is connected to the vehicle's compressed air system, ensuring that the high-pressure air can flow between the rod cavity of the power telescopic cylinder 202; like Figure 5-6 The accumulator 204 includes a cooling fixed sleeve 20401, an accumulator cylinder 20402, an oil-gas separation piston 20403, a charging valve 20404, a ball valve 20405, a push rod 20406, a control piston 20407 and a valve body 20408. The cooling fixed sleeve 20401 is fixed on the vehicle body. The accumulator cylinder 20402 is fixed in the cavity of the cooling fixed sleeve 20401, and forms a certain cavity with the fixed sleeve 20401. After the coolant is filled, a cooling cavity 20411 is formed to transfer the oil heat caused by vibration to the vehicle body 101.

[0026] The two ends of the accumulator barrel 20402 are respectively installed with a charging valve 20404 and a valve body 20408; the oil-gas separation piston 20403 is placed in the accumulator barrel 20402 and can slide in the inner cavity of the accumulator barrel 20402; the cavity between the oil-gas separation piston 20403 and the charging valve 20404 is a nitrogen cavity, and the cavity between the oil-gas separation piston 20403 and the valve body 20408 is a high-pressure oil cavity. The oil-gas separation piston 20403 can ensure that the high-pressure oil cavity 20410 is completely separated from the nitrogen cavity 20409; the charging valve 20404 is used to fill the nitrogen cavity with nitrogen.

[0027] The side wall of the valve body 20408 is provided with a locking oil port 20412, an inlet and return oil port 20415 and a high-pressure oil port 20416; a ball valve 20405 is provided in the center hole of the valve body 20408. The ball valve 20405 includes a valve seat 20417, a valve sleeve 20418, a ball and a spring; the valve seat includes a small diameter part and a large diameter part, the small diameter part is located between the large diameter part and the accumulator cylinder 20402; the small diameter part is placed in the center hole of the valve sleeve 20418, and a sealing ring II is provided between the small diameter part and the center hole of the valve sleeve 20418. The large diameter part of the valve seat 20417 and the valve sleeve 20418 are installed in the center hole of the valve body, and a sealing ring I is provided between the large diameter part, the valve sleeve and the center hole of the valve body.

[0028] The center hole of the valve seat 20417 is a stepped hole, and a ball is arranged at the stepped surface, which can seal the center hole of the valve seat. A pressure plate is arranged at the end of the center hole of the valve seat, and a hole connected to the center hole of the valve seat is arranged on the pressure plate; a spring 20420 is arranged between the ball 20419 and the pressure plate, and the elastic force of the spring 20420 presses the ball 20419 against the stepped surface of the center hole of the valve seat. A radial through hole connected to the center hole of the valve seat is arranged on the small diameter part, and the radial through hole can allow the high-pressure oil entering from the oil inlet and return port 20415 to enter the center hole of the valve seat and then enter the accumulator cylinder 20402. The radial through hole is located between the ball and the large diameter part; the high-pressure oil port 20416 is arranged close to the accumulator cylinder 20402, and the high-pressure oil port 20416 is connected to the center hole of the valve sleeve, and the valve seat can block the high-pressure oil port 20416.

[0029] A control cylinder 20413 is provided at the end of the valve body away from the accumulator cylinder 20402, and a control oil port 20414 is provided on the control oil cylinder 20413, and a control piston 20407 is provided in the control oil cylinder 20413; the piston rod end of the control piston 20407 extends into the central hole of the valve seat, and the piston rod end is sealed with the central hole of the valve seat; the locking oil port 20412 is connected to the cavity between the control oil cylinder 20413 and the valve seat; the oil inlet and return port 20415 is set corresponding to the gap between the large diameter part and the valve sleeve.

[0030] The ball valve 20405 can slide in the valve body 20408 according to the different oil pressures at both ends. When high-pressure oil flows into the oil inlet and return ports, the ball valve 20405 slides to the left, the spring is compressed, and the oil flows into the high-pressure oil chamber of the accumulator 204, and can flow into the rodless chamber of the power telescopic cylinder 202 along the S-shaped oil pipe 203. When high-pressure oil flows into the locking oil port, the ball valve 20405 slides to the right, sealing the oil communication port between the high-pressure oil chamber of the accumulator 204 and the rodless chamber of the power telescopic cylinder 202, thereby ensuring that the power telescopic cylinder 202 no longer extends or retracts, that is, the height of the vehicle bottom from the ground remains unchanged. There is no shock absorption effect in this state. The control piston 20407 is fixedly connected to the push rod 20406. When high-pressure oil flows into the control oil port, the control piston 20407 and the push rod 20406 are pushed to the right, the spring is compressed, and the oil in the high-pressure oil chamber of the accumulator 204 pushes the ball valve 20405 to move to the left and flows out from the oil inlet and return ports.

[0031] like Figure 7-8 As shown, the flow control module 3 also includes a connecting pipe I 301, a cut-off solenoid valve 302, a connecting pipe II 303, a flow meter 304, a connecting pipe III 305, a control valve group 306, a locking accumulator 307, and a locking oil pipe 308. The control valve group 306 also includes a control oil pipe 30601, a retractable reversing valve 30602, a diverter valve 30603, a main oil supply pipe 30604, a main oil return pipe 30609, a locking oil supply pipe 30607, a locking oil return pipe 30609, and a locking reversing valve 30605.

[0032] The oil inlet and return ports of the accumulator 204 are connected to the oil supply port of the control valve group 306 through a pipeline, and the pipeline is formed by connecting pipe I 301, cutting off the solenoid valve 302, connecting pipe II 303, flow meter 304, and connecting pipe III 305 in series. The cutting off solenoid valve 302, the control valve group 306, and the locking accumulator 307 are fixed on the vehicle body 101. The locking oil port of the locking accumulator 307 is connected to the locking oil port of the accumulator 204 through the locking oil pipe 308; the control oil port is connected to the control oil outlet of the control valve group 306 through the control oil pipe 30601. The flow meter 304 detects that the oil flowing into the accumulator 204 reaches the calculated value, controls the cutting off solenoid valve 302 to change from the normally open state to the closed state, and the cutting off oil continues to flow into the accumulator 204, thereby realizing the precise positioning of the vehicle bottom from the ground.

[0033] The oil inlet of the diverter valve 30603 is fixedly connected to the main oil supply pipe 30604, and the two diverter ports of the diverter valve 30603 are respectively connected to the oil inlets of the retractable reversing valve 30602 and the locking reversing valve 30605. The diverter valve 30603, the retractable reversing valve 30602 and the locking reversing valve 30605 are installed and fixed on the vehicle body 101. The retractable reversing valve 30602 and the locking reversing valve 30605 are three-position four-way reversing valves; the two oil outlets of the locking reversing valve 30605 are respectively connected to the oil inlet and the oil return port of the locking accumulator 307 through the locking oil supply pipe 30607 and the locking oil return pipe 30609. The two oil outlets of the retractable reversing valve 30602 are respectively the oil supply port and the control oil outlet of the control valve group 306. The oil supply mechanism of the control oil pipe 30601 and the connecting pipe III 305 is switched by retracting and releasing the reversing valve 30602. The locking reversing valve 30605 switches the oil supply mechanism of the locking oil supply pipe 30607 and the locking oil return pipe 30609.

Claims

1. A vehicle suspension system capable of accurate retraction and positioning, comprising an actuator (1), a suspension assembly (2), and a flow control module (3); Features: The actuator (1) comprises a pulling arm (102), a longitudinal arm assembly (103) and a load-bearing wheel (104); the load-bearing wheel (104) is mounted at the rear end of the longitudinal arm assembly (103), and the load-bearing wheel (104) can rotate flexibly; the front end of the longitudinal arm assembly (103) is fixedly mounted on a hinge shaft, the hinge shaft is mounted on the vehicle body, and the hinge shaft can pivot; one end of the pulling arm (102) is fixedly connected to the hinge shaft; there is an angle between the pulling arm (102) and the longitudinal arm assembly (103); The suspension assembly (2) comprises a power telescopic cylinder (202), an S-shaped oil pipe (203) and an air pipe (205); one end of the power telescopic cylinder (202) is hinged to the vehicle body (101), and the other end is hinged to the pulling arm (102); the accumulator (204) is fixed on the vehicle body (101); the high-pressure oil port of the accumulator (204) is connected to the high-pressure oil port of the power telescopic cylinder (202) through the S-shaped oil pipe (203), so that oil can flow between the rodless chamber of the power telescopic cylinder (202) and the high-pressure oil chamber of the accumulator (204); one end of the air pipe (205) is connected to the high-pressure air port of the power telescopic cylinder (202), and the other end is connected to the compressed air system of the vehicle, so that high-pressure air can flow between the rod chamber of the power telescopic cylinder (202); The flow control module (3) is connected to the pressure accumulator (204) and can store pressure in the pressure accumulator (204).

2. The vehicle suspension system capable of accurate retraction and positioning according to claim 1, characterized in that: The accumulator (204) comprises an accumulator barrel (20402), an oil-gas separation piston (20403), an air charging valve (20404), a ball valve (20405), a push rod (20406), a control piston (20407) and a valve body (20408); the air charging valve (20404) and the valve body (20408) are respectively installed at both ends of the accumulator barrel (20402); the oil-gas separation piston (20403) is disposed in the accumulator barrel (20402) and can slide in the inner cavity of the accumulator barrel (20402); the cavity between the oil-gas separation piston (20403) and the air charging valve (20404) is a nitrogen cavity, and the cavity between the oil-gas separation piston (20403) and the valve body (20408) is a high-pressure oil cavity; The side wall of the valve body (20408) is provided with a locking oil port, an oil inlet and return port, and a high-pressure oil port; a ball valve (20405) is provided in the center hole of the valve body (20408), and the ball valve (20405) includes a valve seat, a valve sleeve, a ball, and a spring; the valve seat includes a small diameter portion and a large diameter portion, and the small diameter portion is located between the large diameter portion and the accumulator cylinder (20402); the small diameter portion is placed in the center hole of the valve sleeve, and a sealing ring II is provided between the small diameter portion and the center hole of the valve sleeve; the large diameter portion of the valve seat and the valve sleeve are installed in the center hole of the valve body, and a sealing ring I is provided between the large diameter portion, the valve sleeve, and the center hole of the valve body; The center hole of the valve seat is a stepped hole, a ball is arranged at the stepped surface, the ball can seal the center hole of the valve seat, a pressure plate is arranged at the end of the center hole of the valve seat, and a hole connected to the center hole of the valve seat is arranged on the pressure plate; a spring is arranged between the ball and the pressure plate, and the spring pressure presses the ball against the stepped surface of the center hole of the valve seat; a radial through hole connected to the center hole of the valve seat is arranged on the small diameter part, and the radial through hole is located between the ball and the large diameter part; the high-pressure oil port is arranged close to the accumulator cylinder (20402), the high-pressure oil port is connected to the center hole of the valve sleeve, and the valve seat can block the high-pressure oil port; A control oil cylinder is provided at the end of the valve body away from the accumulator cylinder (20402), a control oil port is provided on the control oil cylinder, and a control piston (20407) is provided in the control oil cylinder; the piston rod end of the control piston (20407) extends into the central hole of the valve seat; the locking oil port is connected to the cavity between the control oil cylinder and the valve seat; the oil inlet and return ports are arranged corresponding to the gap between the large diameter part and the valve sleeve.

3. The vehicle suspension system capable of accurate retraction and positioning according to claim 2, characterized in that: It also includes a cooling fixing sleeve (20401); the cooling fixing sleeve (20401) is mounted on the vehicle body (101); the accumulator cylinder (20402) is fixed in the cavity of the cooling fixing sleeve (20401); the accumulator cylinder (20402) and the cooling fixing sleeve (20401) form a certain cavity; after the cavity is filled with coolant, a cooling cavity is formed, and the oil heat caused by vibration is transferred to the vehicle body (101).

4. The vehicle suspension system capable of accurate retraction and positioning according to claim 3, characterized in that: The flow control module (3) includes a cut-off solenoid valve (302), a flow meter (304), a control valve group (306), a locking accumulator (307) and a locking oil pipe (308); the oil inlet and return ports of the accumulator (204) are connected to the oil supply port of the control valve group (306) through a pipeline, the cut-off solenoid valve (302) and the flow meter (304) are provided on the pipeline, the cut-off solenoid valve (302) is located between the flow meter (304) and the accumulator (204), the cut-off solenoid valve (302), the control valve group (306) and the locking accumulator (307) are fixed on the vehicle body (101); the locking oil port of the locking accumulator (307) is connected to the locking oil port of the accumulator (204) through the locking oil pipe (308); the control oil port is connected to the control oil outlet of the control valve group (306) through the control oil pipe (30601).

5. The vehicle suspension system capable of accurate retraction and positioning according to claim 4, characterized in that: The control valve group (306) comprises a retractable reversing valve (30602), a diverter valve (30603), a main oil supply pipe (30604), a main oil return pipe (30609), a locking oil supply pipe (30607), a locking oil return pipe (30609) and a locking reversing valve (30605); The oil inlet of the diverter valve (30603) is fixedly connected to the main oil supply pipe (30604), and the two diverter ports of the diverter valve (30603) are respectively connected to the oil inlets of the retractable reversing valve (30602) and the locking reversing valve (30605). The diverter valve (30603), the retractable reversing valve (30602) and the locking reversing valve (30605) are fixedly mounted on the vehicle body (101); the retractable reversing valve (30602) 0602) and the locking reversing valve (30605) are three-position four-way reversing valves; the two oil outlets of the locking reversing valve (30605) are connected to the oil inlet and oil return port of the locking accumulator (307) through the locking oil supply pipe (30607) and the locking oil return pipe (30609) respectively; the two oil outlets of the retractable reversing valve (30602) are the oil supply port and the control oil outlet of the control valve group (306) respectively.

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