Vehicle rear axle alignment system

Abstract

The present application relates to a kind of vehicle rear axle centering systems, including high-pressure accumulator, low-pressure accumulator, oil tank, steering centering cylinder, switching valve and pressure limiting valve, the switching valve is equipped with first oil port, second oil port and third oil port, the first oil port is connected with the high-pressure accumulator, the third oil port is connected with the low-pressure accumulator, the second oil port is connected with the steering centering cylinder, the steering centering cylinder body includes two oil inlets and one oil return, the steering centering cylinder oil return is connected with the oil tank;Through low-pressure accumulator energy recovery and utilization, in addition, low-pressure accumulator makes the floating piston of steering centering cylinder instantaneously follow the piston rod movement of steering centering cylinder, improves the rear axle centering locking speed;High-pressure accumulator improves the stiffness of vehicle rear axle centering hydraulic system, improves the reliability of vehicle rear axle centering hydraulic system, high-pressure accumulator can effectively absorb instantaneous excitation of road, prevent the fatigue influence caused by instantaneous excitation of road to structural member.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of auxiliary driving, in particular to a vehicle rear axle centering system. BACKGROUND

[0002] In recent years, with the rapid development of logistics transportation and infrastructure, the demand for large logistics vehicles and large engineering vehicles has increased significantly. At the same time, with the deepening of new military reform, the demand for large military wheeled vehicles has also increased significantly. The high mobility and high passability of these vehicles with large mass, large wheelbase and multiple axles are particularly important, and the rear axle steering technology has emerged as the times require. The electrically controlled hydraulic rear axle steering technology has been widely used because it can make the vehicle rear axle steer or center conveniently and quickly. The vehicle steering and centering system disclosed in Chinese patent CN102030037A usually needs two or more reversing valves to control the oil inlet and oil return of the centering cylinder, and the control valve group of the steering assist cylinder is jointly controlled, the control logic is complex, the reliability is poor, there are safety hazards, and because there is a large friction force between the floating piston and the centering cylinder body, the floating piston cannot follow or immediately follow the movement of the piston rod, thereby affecting the centering locking speed. In addition, due to the excitation of the road surface, the structural rods of the centering system are prone to fatigue failure. SUMMARY

[0003] The purpose of the present application is to solve the problems of the prior art, that is, the need for multiple reversing valves to control the oil inlet and oil return of the centering cylinder, the joint control of the control valve group of the steering assist cylinder, the complex control logic, the poor reliability, the safety hazards, and the fatigue failure of the structural rods of the centering system due to the excitation of the road surface.

[0004] The present application is realized by adopting the following technical solutions:

[0005] A vehicle rear axle centering system, comprising a high-pressure accumulator, a low-pressure accumulator, an oil tank, a steering and centering cylinder, a switching valve and a pressure limiting valve, the switching valve is provided with a first oil port, a second oil port and a third oil port, the first oil port is connected with the high-pressure accumulator, the third oil port is connected with the low-pressure accumulator, the second oil port is connected with the steering and centering cylinder, the steering and centering cylinder body comprises two oil inlet ports and one oil return port, the oil return port of the steering and centering cylinder is connected with the oil tank.

[0006] Preferably: the steering centering cylinder comprises a piston rod, a left floating piston, a right floating piston, a centering cylinder body, the centering cylinder body is provided with an annular boss, one end of the piston rod is arranged between the left floating piston and the right floating piston, and the other end passes through the left floating piston and extends out of the centering cylinder body.

[0007] Preferably: the pressure limiting valve has a fourth oil port and a fifth oil port, the fourth oil port is connected with the second oil port of the switching valve, the fifth oil port is connected with the oil tank, and a preset pressure value is arranged on the pressure limiting valve for protecting the high-pressure accumulator.

[0008] Preferably: the switching valve is used for controlling the rod cavity and the rodless cavity of the steering centering cylinder to be connected with the high-pressure accumulator in the steering centering cylinder centering locking state and connected with the low-pressure accumulator in the steering centering cylinder low-pressure follow-up state.

[0009] Preferably: the valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system comprises a steering oil pump, a servo valve, a steering assist cylinder and an electromagnetic reversing valve, the steering assist cylinder comprises a rod cavity and a rodless cavity, the electromagnetic reversing valve has a sixth oil port, a seventh oil port and an eighth oil port, the sixth oil port is connected with the oil tank, the seventh oil port is connected with the rod cavity of the steering assist cylinder, the eighth oil port is connected with the rodless cavity of the steering assist cylinder, the rod cavity is connected with the oil tank through the servo valve, the rodless cavity is connected with the steering oil pump through the servo valve, and the steering oil pump is connected with the oil tank.

[0010] Compared with the prior art, the present application has the following beneficial technical effects:

[0011] The low-pressure accumulator is adopted to realize energy recovery and utilization, in addition, the low-pressure accumulator enables the floating piston of the steering centering cylinder to instantaneously follow the movement of the piston rod of the steering centering cylinder, thereby improving the rear axle centering locking speed; the vehicle rear axle centering hydraulic system does not need a hydraulic oil source, has small noise, low cost, is convenient to use, is energy-saving and environment-friendly; the high-pressure accumulator improves the rigidity of the vehicle rear axle centering hydraulic system and improves the reliability of the vehicle rear axle centering hydraulic system, in addition, the high-pressure accumulator can effectively absorb the instantaneous excitation of the road surface and prevent the fatigue influence of the instantaneous excitation of the road surface on the structural member. BRIEF DESCRIPTION OF DRAWINGS

[0012] The utility model will be further described in connection with the drawings:

[0013] Fig. 1 It is vehicle rear axle centering system structure schematic diagram of the present application;

[0014] Fig. 2 It is valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system structure schematic diagram of the present application;

[0015] Fig. 3 Turning to the present application, a schematic view of a centering cylinder structure is shown.

[0016] Reference Signs List

[0017] 1, high pressure accumulator; 2, switching valve; 21, first oil port; 22, second oil port; 23, third oil port; 3, steering centering cylinder; 31, piston rod; 32, centering cylinder body; 321, annular boss; 33, left floating piston; 34, right floating piston; 35, ninth oil port; 36, oil return port; 4, pressure limiting valve; 41, fourth oil port; 42, fifth oil port; 5, oil tank; 6, low pressure accumulator; 7, steering oil pump; 8, servo valve; 9, steering assist cylinder; 10, electromagnetic switching valve; 101, sixth oil port; 102, seventh oil port; 103, eighth oil port. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be described in detail below in conjunction with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. In the description of the present application, it should be noted that unless otherwise specifically defined and limited, the terms "provided", "mounted", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0019] Embodiment one:

[0020] As shown in Figs. 1 to 3 As shown in Fig. 1 and Fig. 3 The present application provides a vehicle rear axle centering system, which comprises a high pressure accumulator 1, a switching valve 2, a steering centering cylinder 3, an oil tank 5 and a low pressure accumulator 6. The switching valve 2 has a first oil port 21, a second oil port 22 and a third oil port 23. The first oil port 21 is connected with the high pressure accumulator 1. The third oil port 23 is connected with the low pressure accumulator 6. The second oil port 22 is connected with the ninth oil port 35 of the steering centering cylinder 3. The switching valve 2 is used to control the connection of the rod cavity and the rodless cavity of the steering centering cylinder 3 with the high pressure accumulator 1 in the centering locking state of the steering centering cylinder 3 and with the low pressure accumulator 6 in the low pressure follow-up state of the steering centering cylinder 3.

[0021] The steering centering cylinder 3 comprises a centering cylinder body 32 and a piston rod 31, a left floating piston 33 and a right floating piston 34 arranged in the centering cylinder body, one end of the piston rod 31 is arranged between the left floating piston 33 and the right floating piston 34, and the other end penetrates through the left floating piston 33 and extends out of the centering cylinder body 32.

[0022] Two ninth oil ports 35 and one oil return port 36 are arranged on the centering cylinder body 32, and the oil return port 36 is connected with the oil tank 5.

[0023] In addition, a pressure limiting valve 4 is arranged in the vehicle rear axle centering hydraulic system, the pressure limiting valve 4 has a fourth oil port 41 and a fifth oil port 42, the fourth oil port 41 is connected with the oil port 22 of the switching valve, the fifth oil port 42 is connected with the oil tank 5, and a pressure value is preset on the pressure limiting valve 4 for protecting the high-pressure accumulator 1.

[0024] As shown in Fig. 2 The vehicle rear axle centering system provided by the application is used in cooperation with a valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system, the valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system comprises a steering oil pump 7, a servo valve 8, a steering assist cylinder 9 and an electromagnetic reversing valve 10, the steering oil pump 7 provides power to the steering assist cylinder 9 through the servo valve 8, and the electromagnetic reversing valve 10 has a sixth oil port 101, a seventh oil port 102 and an eighth oil port 103, the sixth oil port 101 is connected with the oil tank 5, the seventh oil port 102 is connected with a rod cavity of the steering assist cylinder 9, and the eighth oil port 103 is connected with a rodless cavity of the steering assist cylinder 9.

[0025] Working principle:

[0026] As shown in Fig. 1 and Fig. 2 When the vehicle is in a four-wheel steering working condition and travels, the steering centering cylinder 3 is in a low-pressure follow-up state, the steering assist cylinder 9 pushes the piston rod 31 of the steering centering cylinder 3 to move left or right, the left floating piston 33 or the right floating piston 34 moves left or right accordingly, and the oil in the steering centering cylinder 3 flows into the low-pressure accumulator 6 through the switching valve 2, so that energy recovery is realized; when the vehicle is in a front-wheel steering working condition and travels, the piston rod 31 of the steering centering cylinder 3 is pushed by the steering assist cylinder 9 to return to a centering locking state, in this process, the energy stored in the low-pressure accumulator 6 makes the left floating piston 33 and the right floating piston 34 immediately follow the movement of the piston rod 31, so that the rear axle centering locking speed is improved and the rear axle is smoothly centered without impact.

[0027] When the rear axle alignment lock is completed, the first oil port 21 of the switching valve 2 communicates with the second oil port 22, the rod cavity and the rodless cavity of the steering alignment cylinder 3 communicate with the high-pressure accumulator 1, so as to improve the stiffness of the vehicle rear axle alignment hydraulic system.

[0028] Fig. 1 The A port in the above is used to periodically supplement a small amount of oil to the high-pressure accumulator 1, so as to maintain the pressure of the high-pressure accumulator 1 without additional hydraulic oil.

[0029] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0030] The above is described, and the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the present application; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A vehicle rear axle alignment system, characterized by: The system comprises a high-pressure accumulator, a low-pressure accumulator, an oil tank, a steering and centering cylinder, a switching valve and a pressure limiting valve, the switching valve is provided with a first oil port, a second oil port and a third oil port, the first oil port is connected with the high-pressure accumulator, the third oil port is connected with the low-pressure accumulator, and the second oil port is connected with the steering and centering cylinder.

2. The vehicle rear axle alignment system of claim 1, wherein: The steering and centering cylinder comprises a piston rod, a left floating piston, a right floating piston and a centering cylinder body, the centering cylinder body is provided with an annular boss, one end of the piston rod is arranged between the left floating piston and the right floating piston, and the other end of the piston rod passes through the left floating piston and extends out of the centering cylinder body.

3. The vehicle rear axle alignment system of claim 1, wherein, The pressure limiting valve is provided with a fourth oil port and a fifth oil port, the fourth oil port is connected with the second oil port of the switching valve, and the fifth oil port is connected with the oil tank, and the pressure limiting valve is provided with a preset pressure value for protecting the high-pressure accumulator.

4. The vehicle rear axle alignment system of claim 1, wherein, The switching valve is used for controlling the rod cavity and the rodless cavity of the steering and centering cylinder to be connected with the high-pressure accumulator in the centering locking state of the steering and centering cylinder and to be connected with the low-pressure accumulator in the low-pressure follow-up state of the steering and centering cylinder.

5. The vehicle rear axle alignment system of claim 1, wherein, The system further comprises a valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system, the valve-controlled cylinder type electro-hydraulic position servo closed-loop steering system comprises a steering oil pump, a servo valve, a steering assist cylinder and an electromagnetic reversing valve, the steering assist cylinder comprises a rod cavity and a rodless cavity, the electromagnetic reversing valve is provided with a sixth oil port, a seventh oil port and an eighth oil port, the sixth oil port is connected with the oil tank, the seventh oil port is connected with the rod cavity of the steering assist cylinder, and the eighth oil port is connected with the rodless cavity of the steering assist cylinder, the rod cavity is connected with the oil tank through the servo valve, the rodless cavity is connected with the steering oil pump through the servo valve, and the steering oil pump is connected with the oil tank.

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