Rear suspension hydraulic system of tractor

Abstract

The utility model provides a tractor rear suspension hydraulic system which comprises an oil pump, a reversing valve, a bypass valve and a suspension oil cylinder, an inlet of the oil pump is connected with an oil tank, an outlet of the oil pump is connected with a pressure oil port of the reversing valve, and an oil return port of the reversing valve is connected with the oil tank; a first interface of the reversing valve is connected with a control oil port of the bypass valve, and a second interface of the reversing valve is provided with a descending branch which is connected with the suspension oil cylinder; a lifting branch and a bypass branch are arranged on an oil way from the oil pump to the reversing valve, a one-way valve is arranged on the lifting branch, and an outlet of the one-way valve is connected with the suspension oil cylinder. The bypass branch is connected with an inlet of the bypass valve, and an outlet of the bypass valve is connected with the oil tank. When the machine tool is lifted to the required height, the bypass valve is controlled to be conducted through the reversing valve, pressure oil of the oil pump returns to the oil tank through the bypass valve, and pressure building of a hydraulic pipeline is avoided; the response speed is high; and the load keeping function of the suspension oil cylinder is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of tractor rear suspension systems, in particular to a tractor rear suspension hydraulic system. Background Art

[0002] The rear suspension system of the tractor is used for carrying implements, and it mainly includes a hydraulic system and a hanging component for hanging implements. In its hydraulic system, the hanging cylinder is connected to the hanging component to support and control the height of the carried implements. When the hanging cylinder is extended, the implement is raised, and when the hanging cylinder is retracted, the implement is lowered. In the existing suspension hydraulic system, the control of the suspension cylinder generally uses a valve to directly supply oil to the cylinder. When the implement is lifted to the required height, the valve is closed or the valve and the pump are closed. When only the valve is closed, it is easy to cause the hydraulic pipeline at the outlet of the hydraulic pump to be pressurized, the hydraulic system is easily damaged, and the service life is short. When the pump is turned off, the restart delay is long, and it cannot respond to the next lifting command in time, affecting the timeliness of the hydraulic system. Utility Model Content

[0003] The technical problem to be solved by the utility model is: how to avoid the pressure build-up in the hydraulic pipeline and respond to the next lifting instruction in time under the premise of ensuring the load holding function of the suspension oil cylinder.

[0004] The technical solution of the utility model to solve the above technical problems is as follows:

[0005] The utility model provides a tractor rear suspension hydraulic system, comprising an oil pump, a reversing valve, a bypass valve, and a suspension oil cylinder, wherein the inlet of the oil pump is connected to an oil tank, the outlet of the oil pump is connected to a pressure oil port of the reversing valve, and the oil return port of the reversing valve is connected to the oil tank; a first interface of the reversing valve is connected to a control oil port of the bypass valve, a second interface of the reversing valve is provided with a descending branch, and the descending branch is connected to the suspension oil cylinder; a lifting branch and a bypass branch are provided on the oil path from the oil pump to the reversing valve, a one-way valve is provided on the lifting branch, and the outlet of the one-way valve is connected to the suspension oil cylinder; the bypass branch is connected to the inlet of the bypass valve, and the outlet of the bypass valve is connected to the oil tank.

[0006] The beneficial effects of the utility model are:

[0007] By adopting the utility model, when the machine is lifted to the required height, the reversing valve is used to control the oil to enter the bypass valve, so that the bypass valve is turned on, and the pressure oil of the oil pump returns to the oil tank through the bypass valve, thereby avoiding the pressure buildup in the hydraulic pipeline; by changing the valve position of the reversing valve, the lifting instruction can be responded to again, and the response speed is fast; at the same time, the one-way valve is used to restrict the oil flow direction of the lifting branch, and the reversing valve is used to control the on-off of the lowering branch, thereby ensuring the load holding function of the suspension cylinder.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, a throttle valve is also provided on the descending branch.

[0010] It is convenient to control the retraction speed of the suspension cylinder, thereby controlling the lowering speed of the machine to avoid impact.

[0011] Furthermore, the valve core of the reversing valve is provided with a left position, a middle position and a right position, and the valve core of the reversing valve can switch to the left position, the middle position or the right position by moving along its own axial direction; when the valve core works in the left position, the pressure oil port of the reversing valve is connected to the first interface, and the return oil port is connected to the second interface; when the valve core works in the middle position, the pressure oil port of the reversing valve is connected to the first interface, and the return oil port and the second interface are both closed; when the valve core works in the right position, the pressure oil port and the second interface of the reversing valve are both closed, and the first interface is connected to the return oil port.

[0012] In the initial state, the valve core of the reversing valve is in the middle position, which is convenient for quickly switching the valve core to the right position or the left position, thereby quickly switching the lifting state or the lowering state; in the lifting state or the lowering state, the valve core can also be quickly switched to the middle position to achieve load holding; the response speed is fast.

[0013] Furthermore, the reversing valve is a three-position two-way solenoid valve.

[0014] The working position of the reversing valve can be controlled by electromagnetic force, and the operation is convenient and the response speed is fast.

[0015] Furthermore, the valve core of the bypass valve is provided with a left position and a right position. The valve core of the bypass valve can switch to the left position or the right position by moving along its own axial direction. When the left position of the valve core is working, the inlet and outlet of the bypass valve are connected; when the right position of the valve core is working, the inlet and outlet of the bypass valve are closed; the control oil port of the bypass valve is located at the left end of the valve core of the bypass valve.

[0016] The oil through the first interface of the reversing valve pushes the left end of the valve core of the bypass valve to move rightward, so that the left station works, and the inlet and outlet of the bypass valve are connected, which is convenient for operation.

[0017] Furthermore, a spring is provided at the right end of the valve core of the bypass valve, and the spring is connected to the inner wall of the shell of the bypass valve. When the spring is compressed and deformed, the elastic force of the spring can push the valve core of the bypass valve to move leftward.

[0018] When there is no pressure on the first interface of the reversing valve, the valve core of the bypass valve is pushed to the left by the elastic force of the spring, so that the right position works and the bypass valve remains in a normally closed state. The structure is simple and the reliability is good.

[0019] Furthermore, the suspension oil cylinder is also connected to an overload branch, an overload valve is provided on the overload branch, and an outlet of the overload valve is connected to the oil tank.

[0020] When the rear suspension is transported or transferred with load, if the pressure in the suspension cylinder is too high due to a large load impact, part of the oil can be quickly released by the overload valve, avoiding damage to the hydraulic pipeline or suspension cylinder and improving safety.

[0021] Furthermore, the suspension cylinder is provided with a lifting main circuit, which is respectively connected to the overload branch, the lifting branch and the lowering branch.

[0022] The branches are combined and then connected to the suspension cylinder, which is easy to assemble. The suspension cylinder can be replaced independently and maintenance is convenient.

[0023] Furthermore, the oil tank is provided with an oil return main circuit, which is respectively connected to the oil return port of the reversing valve, the outlet of the bypass valve and the outlet of the overload valve.

[0024] The oil return pipelines are connected to the oil tank after being collected, which is convenient for assembly, reduces the number of oil tank interfaces, reduces the cost of the oil tank, and facilitates maintenance.

[0025] Furthermore, the outlet of the oil pump is also provided with a safety branch, the safety branch is provided with a safety valve, and the outlet of the safety valve is connected to the oil tank.

[0026] When the outlet pressure of the oil pump is too high or the hydraulic pipeline is blocked, part of the oil can be quickly released through the safety valve to protect the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the initial state of the utility model.

[0028] Figure 2 It is a structural schematic diagram of the utility model in a lifting state.

[0029] Figure 3 It is a structural schematic diagram of the utility model in a descending state.

[0030] In the accompanying drawings, the technical features represented by the reference numerals are as follows:

[0031] 1-Oil pump; 2-Oil tank; 3-Reversing valve; 4-Bypass valve; 5-Suspension cylinder; 6-Check valve; 7-Throttle valve; 8-Spring; 9-Overload valve; 10-Safety valve; 11-Lifting main circuit; 12-Oil return main circuit. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] This utility model refers to Figure 1-3 ,In the figure, except for the hydraulic components, the direction of the arrow indicates the flow direction of the hydraulic oil.

[0034] The utility model provides a tractor rear suspension hydraulic system, comprising an oil pump 1, a reversing valve 3, a bypass valve 4, and a suspension cylinder 5, wherein the inlet of the oil pump 1 is connected to a fuel tank 2, the outlet of the oil pump 1 is connected to a pressure oil port of the reversing valve 3, and the oil return port of the reversing valve 3 is connected to the fuel tank 2; the first interface of the reversing valve 3 is connected to a control oil port of the bypass valve 4, the second interface of the reversing valve 3 is provided with a descending branch, and the descending branch is connected to the suspension cylinder 5; a lifting branch and a bypass branch are provided on the oil circuit from the oil pump 1 to the reversing valve 3, a check valve 6 is provided on the lifting branch, and the outlet of the check valve 6 is connected to the suspension cylinder 5; the bypass branch is connected to the inlet of the bypass valve 4, and the outlet of the bypass valve 4 is connected to the fuel tank 2.

[0035] principle:

[0036] The reversing valve 3 is a prior art, and a three-position two-way reversing valve, a three-position three-way reversing valve, etc. can be used. The bypass valve 4 is a prior art, and in addition to the inlet and outlet, the valve cavity at one end of the valve core is also connected to a control oil port. When the control oil port is pressurized, it can drive the valve core to move, thereby controlling the conduction of the bypass valve 4. When there is no pressure in the control oil port, the valve core returns to its position under the action of the spring 8, thereby returning to the normally closed state. The working state of the utility model is as follows:

[0037] In the initial state, if Figure 1 As shown: the pressure oil port of the reversing valve 3 is connected to the first interface, and the return oil port and the second interface are both closed; the pressure oil of the oil pump 1 enters the control oil port of the bypass valve 4 through the first interface of the reversing valve 3, and the bypass valve 4 is turned on; the pressure oil of the oil pump 1 directly returns to the oil tank 2 through the bypass branch and the bypass valve 4.

[0038] In the lifting state, Figure 2 As shown: the pressure oil port and the second interface of the reversing valve 3 are both closed, and the first interface is connected to the oil return port; the control oil port of the bypass valve 4 returns oil to the oil tank 2 through the first interface and the oil return port of the reversing valve 3, and the bypass valve 4 is closed; the pressure oil of the oil pump 1 enters the suspension cylinder 5 through the lifting branch and the one-way valve 6, and the suspension cylinder 5 extends, and the machine is lifted. When the machine is lifted to the required height, the reversing valve 3 returns to the initial state, the second interface of the reversing valve 3 is still closed, and the load of the suspension cylinder 5 is maintained.

[0039] In the descending state, Figure 3 As shown: the pressure oil port of the reversing valve 3 is connected to the first interface, and the return oil port is connected to the second interface; the pressure oil of the oil pump 1 enters the control oil port of the bypass valve 4 through the first interface of the reversing valve 3, and the bypass valve 4 is turned on; the pressure oil of the oil pump 1 directly returns to the oil tank 2 through the bypass branch and the bypass valve 4; the pressure oil in the suspension cylinder 5 returns to the oil tank 2 through the descending branch, the second interface of the reversing valve 3, and the return oil port, the suspension cylinder 5 retracts, and the machine descends. When the machine descends to the required height, the reversing valve 3 returns to the initial state, and the load of the suspension cylinder 5 is maintained.

[0040] In summary, by adopting the utility model, when the machine is lifted to the required height, the oil is controlled to enter the bypass valve 4 through the reversing valve 3, so that the bypass valve 4 is turned on, and the pressure oil of the oil pump 1 returns to the oil tank 2 through the bypass valve 4, thereby avoiding the pressure buildup in the hydraulic pipeline; by changing the valve position of the reversing valve 3, the lifting instruction can be responded to again, and the response speed is fast; at the same time, the oil flow direction of the lifting branch is constrained by the one-way valve 6, and the opening and closing of the descending branch is controlled by the reversing valve 3, thereby ensuring the load holding function of the suspension cylinder 5.

[0041] Furthermore, a throttle valve 7 is provided on the descending branch.

[0042] It is convenient to control the retraction speed of the suspension cylinder 5, thereby controlling the lowering speed of the machine to avoid impact.

[0043] Furthermore, the valve core of the reversing valve 3 is provided with a left position, a middle position and a right position, and the valve core of the reversing valve 3 can be switched to the left position, the middle position or the right position by moving along its own axial direction; when the valve core works in the left position, the pressure oil port of the reversing valve 3 is connected to the first interface, and the return oil port is connected to the second interface; when the valve core works in the middle position, the pressure oil port of the reversing valve 3 is connected to the first interface, and the return oil port and the second interface are both closed; when the valve core works in the right position, the pressure oil port of the reversing valve 3 and the second interface are both closed, and the first interface is connected to the return oil port.

[0044] Note: The housing of the reversing valve 3 is provided with a working position, which is provided with a first interface, a second interface, a pressure oil port and a return oil port. When any of the left position, the middle position or the right position of the valve core moves to the working position, the position works. Different groove channels are opened in the left position, the middle position or the right position of the valve core, so as to control different communication relationships between the first interface, the second interface, the pressure oil port and the return oil port.

[0045] In the initial state, the valve core of the reversing valve 3 is in the middle position, which is convenient for quickly switching the valve core to the right position or the left position, thereby quickly switching the lifting state or the lowering state; in the lifting state or the lowering state, the valve core can also be quickly switched to the middle position to achieve load holding; the response speed is fast.

[0046] Furthermore, the reversing valve 3 is a three-position two-way solenoid valve.

[0047] The working position of the reversing valve 3 can be controlled by electromagnetic force, and the operation is convenient and the response speed is fast.

[0048] Furthermore, a left position and a right position are provided on the valve core of the bypass valve 4. The valve core of the bypass valve 4 can be switched to the left position or the right position by moving along its own axial direction. When the left position of the valve core works, the inlet and outlet of the bypass valve 4 are connected; when the right position of the valve core works, the inlet and outlet of the bypass valve 4 are closed; the control oil port of the bypass valve 4 is located at the left end of the valve core of the bypass valve 4.

[0049] Note: A working position is provided on the shell of the bypass valve 4, and an inlet and an outlet are provided at the working position. When the left position or the right position of the valve core moves to the working position, the position works.

[0050] The oil through the first interface of the reversing valve 3 pushes the left end of the valve core of the bypass valve 4 to move rightward, so that the left station works, and the inlet and outlet of the bypass valve 4 are connected, which is convenient for operation.

[0051] Furthermore, a spring 8 is provided at the right end of the valve core of the bypass valve 4, and the spring 8 is connected to the inner wall of the shell of the bypass valve 4. When the spring 8 is compressed and deformed, the elastic force of the spring 8 can push the valve core of the bypass valve 4 to move leftward.

[0052] When there is no pressure on the first interface of the reversing valve 3, the elastic force of the spring 8 pushes the valve core of the bypass valve 4 to move leftward, so that the right position works and the bypass valve 4 remains in a normally closed state, with a simple structure and good reliability.

[0053] Furthermore, the suspension oil cylinder 5 is also connected to an overload branch, and an overload valve 9 is provided on the overload branch, and the outlet of the overload valve 9 is connected to the oil tank 2 .

[0054] When the rear suspension is transported or transferred with load, if the pressure in the suspension cylinder 5 is too high due to a large load impact, part of the oil can be quickly depressurized by the overload valve 9, avoiding damage to the hydraulic pipeline or the suspension cylinder 5 and improving safety.

[0055] Furthermore, the suspension cylinder 5 is provided with a lifting main circuit 11, and the lifting main circuit 11 is respectively connected to the overload branch, the lifting branch and the lowering branch.

[0056] After the branches are collected, they are connected to the suspension cylinder 5, which is convenient for assembly. The suspension cylinder 5 can be replaced independently, which is convenient for maintenance.

[0057] Furthermore, the oil tank 2 is provided with an oil return main line 12 , which is respectively connected to the oil return port of the reversing valve 3 , the outlet of the bypass valve 4 and the outlet of the overload valve 9 .

[0058] The oil return pipelines are connected to the oil tank 2 after being collected, which is convenient for assembly, reduces the number of interfaces of the oil tank 2, and makes the cost of the oil tank 2 low and easy to maintain.

[0059] Furthermore, a safety branch is provided at the outlet of the oil pump 1 , a safety valve 10 is provided on the safety branch, and the outlet of the safety valve 10 is connected to the oil tank 2 .

[0060] When the outlet pressure of the oil pump 1 is too high or the hydraulic line is blocked, part of the oil can be quickly depressurized through the safety valve 10 to protect the hydraulic system.

[0061] In the description of the present invention, it should be understood that if there are descriptive terms indicating orientation, direction or positional relationship, such as: "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of understanding the present invention and simplifying the description, and does not indicate or imply that the referred part, element or whole must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0062] In addition, if there are order description terms, such as "first", "second", etc., their purpose in this specification is to facilitate understanding or simplify description. For example, in order to distinguish multiple technical features of the same type or function, but they have to be mentioned separately, this specification may use prefix or suffix order description terms to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0063] In the present utility model, if the terms describing the relative functional relationship of the structures are used, such as "install", "connect", "connect", "fix", etc., they should be understood in a broad sense unless otherwise clearly specified and limited. For example, "install", "connect", "connect", etc. can be a fixed connection, a detachable connection, or an integrated one; can be a mechanical connection or an electrical connection; can be a direct connection or an indirect connection through an intermediate medium, can be the internal connection of two elements or the interaction relationship between two elements; "fix" can be an integrated fixation or a detachable fixation through fasteners; can be a direct fixation or a fixation through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above-mentioned descriptive terms in the present utility model can be understood according to the specific circumstances, the context, the coherence of the context, etc.

[0064] In the present invention, if there are descriptive terms with subsidiary or connecting meanings, for example, the first feature is "on" or "below" the second feature, unless otherwise clearly specified and limited, it should not be interpreted in a restrictive manner. For example, "on" or "below" can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the context, etc.

[0065] Furthermore, the first feature being “above”, “above”, and “above” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “below”, “below”, and “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0066] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments, examples and features of the different embodiments and examples described in this specification without contradiction, and these combinations or combinations shall all fall within the scope summarized by the utility model.

[0067] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and cannot be construed as limitations on the present invention. A person skilled in the art can change, modify, replace and modify the above embodiments within the scope of information available from public channels and in combination with the technical inspiration provided by the present application documents.

Claims

1. A tractor rear suspension hydraulic system, characterized in that: The invention comprises an oil pump (1), a reversing valve (3), a bypass valve (4), and a suspension oil cylinder (5); the inlet of the oil pump (1) is connected to an oil tank (2); the outlet of the oil pump (1) is connected to a pressure oil port of the reversing valve (3); and the return oil port of the reversing valve (3) is connected to the oil tank (2); the first interface of the reversing valve (3) is connected to a control oil port of the bypass valve (4); the second interface of the reversing valve (3) is provided with a descending branch, and the descending branch is connected to the suspension oil cylinder (5); the oil path from the oil pump (1) to the reversing valve (3) is provided with a lifting branch and a bypass branch, and a check valve (6) is provided on the lifting branch, and the outlet of the check valve (6) is connected to the suspension oil cylinder (5); the bypass branch is connected to the inlet of the bypass valve (4), and the outlet of the bypass valve (4) is connected to the oil tank (2).

2. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The descending branch line is also provided with a throttle valve (7).

3. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The valve core of the reversing valve (3) is provided with a left position, a middle position and a right position. The valve core of the reversing valve (3) can be switched to the left position, the middle position or the right position by moving along its own axial direction; when the valve core is working in the left position, the pressure oil port of the reversing valve (3) is connected to the first interface, and the return oil port is connected to the second interface; when the valve core is working in the middle position, the pressure oil port of the reversing valve (3) is connected to the first interface, and the return oil port and the second interface are both closed; when the valve core is working in the right position, the pressure oil port of the reversing valve (3) and the second interface are both closed, and the first interface is connected to the return oil port.

4. The tractor rear suspension hydraulic system according to claim 3, characterized in that: The reversing valve (3) is a three-position two-way solenoid valve.

5. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The valve core of the bypass valve (4) is provided with a left position and a right position. The valve core of the bypass valve (4) can be switched to the left position or the right position by moving along its own axial direction. When the left position of the valve core is working, the inlet and outlet of the bypass valve (4) are connected; when the right position of the valve core is working, the inlet and outlet of the bypass valve (4) are closed. The control oil port of the bypass valve (4) is located at the left end of the valve core of the bypass valve (4).

6. The tractor rear suspension hydraulic system according to claim 5, characterized in that: A spring (8) is provided at the right end of the valve core of the bypass valve (4), and the spring (8) is connected to the inner wall of the shell of the bypass valve (4). When the spring (8) is compressed and deformed, the elastic force of the spring (8) can push the valve core of the bypass valve (4) to move leftward.

7. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The suspension oil cylinder (5) is also connected to an overload branch, an overload valve (9) is provided on the overload branch, and the outlet of the overload valve (9) is connected to the oil tank (2).

8. The tractor rear suspension hydraulic system according to claim 7, characterized in that: The suspension oil cylinder (5) is provided with a lifting main circuit (11), and the lifting main circuit (11) is respectively connected to the overload branch circuit, the lifting branch circuit and the lowering branch circuit.

9. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The oil tank (2) is provided with an oil return main line (12), which is respectively connected to the oil return port of the reversing valve (3), the outlet of the bypass valve (4) and the outlet of the overload valve (9).

10. The tractor rear suspension hydraulic system according to claim 1, characterized in that: The outlet of the oil pump (1) is also provided with a safety branch, on which a safety valve (10) is provided, and the outlet of the safety valve (10) is connected to the oil tank (2).

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