Active independent suspension hydraulic control system and tractor

Abstract

The present application relates to a kind of active independent suspension hydraulic control system and tractor of the system, including suspension oil cylinder, large cavity accumulator and small cavity accumulator, the rodless cavity of the suspension oil cylinder is connected with large cavity accumulator between suspension damping adjusting pipeline, the suspension damping adjusting pipeline is equipped with damping valve, the rod cavity of the suspension oil cylinder is connected with small cavity accumulator, suspension bridge control circuit is connected between the suspension oil cylinder and oil tank, the suspension bridge control circuit includes height adjusting pipeline and stiffness adjusting pipeline, the height adjusting pipeline, stiffness adjusting pipeline are equipped with height adjusting valve and stiffness adjusting valve respectively.In the present application, the soft and hard of suspension system are adjusted by suspension damping adjusting pipeline, the height and stiffness of suspension bridge are adjusted by suspension bridge control circuit, and the division of labor is clear, high reliability, and can be adapted to different road conditions.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery control system technology, specifically to an active independent suspension hydraulic control system and a tractor. Background Technology

[0002] In vehicle suspension systems, adjusting the stiffness of the suspension is a crucial means of improving vehicle performance and comfort. Traditional suspension systems typically achieve functions such as simultaneous raising and lowering of the suspension through mechanical structures or simple hydraulic controls. However, this adjustment method often suffers from drawbacks such as slow response speed, limited adjustment range, and inability to adjust according to actual working conditions. In particular, under complex terrain or load variations, the suspension system's adaptability is insufficient, which can easily lead to reduced vehicle driving stability or weakened traction. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an active independent suspension hydraulic control system and a tractor. The control system adjusts the stiffness of the suspension system by regulating the flow of oil into and out of the accumulator. Furthermore, the different modes of the suspension system are combined with the stiffness and height of the suspension bridge to facilitate adaptation to actual working conditions.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: An active independent suspension hydraulic control system includes a suspension cylinder, a large-cavity accumulator and a small-cavity accumulator. A suspension damping adjustment pipeline is connected between the rodless chamber of the suspension cylinder and the large-cavity accumulator. The suspension damping adjustment pipeline is equipped with a damping valve. The rod chamber of the suspension cylinder is connected to the small-cavity accumulator. A suspension bridge control circuit is connected between the suspension cylinder and the oil tank. The suspension bridge control circuit includes a height adjustment pipeline and a stiffness adjustment pipeline. The height adjustment pipeline and the stiffness adjustment pipeline are respectively equipped with a height adjustment valve and a stiffness adjustment valve.

[0005] The beneficial effects of this invention are: the suspension damping adjustment pipeline adjusts the stiffness of the suspension system, and the suspension bridge control circuit adjusts the height and stiffness of the suspension bridge. The division of labor is clear, the reliability is high, and it can be adapted to different road conditions.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the height adjustment pipeline includes a height lifting section and a height lowering section. The height lifting section is connected between the rodless chamber of the suspension cylinder and the pump outlet P of the oil tank, and is equipped with a height lifting valve. The height lowering section is connected between the rodless chamber of the suspension cylinder and the return port T of the oil tank, and is equipped with a height lowering valve. The height lifting section and the height lowering section are not connected simultaneously.

[0008] The beneficial effect of adopting the above-mentioned further scheme is that the height lifting pipe section and the height lowering pipe section are not connected at the same time, so that the lifting action is independently controllable, and has the advantages of simple control and safety and reliability.

[0009] Furthermore, the stiffness adjustment pipeline includes a stiffness lifting section and a stiffness lowering section. The stiffness lifting section is connected between the rod chamber of the suspension cylinder and the pump oil outlet P of the oil tank, and is equipped with a stiffness lifting valve. The stiffness lowering section is connected between the rod chamber of the suspension cylinder and the return oil port T of the oil tank, and is equipped with a stiffness lowering valve. The stiffness lifting section and the stiffness lowering section are not connected simultaneously.

[0010] The beneficial effect of adopting the above-mentioned further scheme is that the stiffness-raising pipe section and the stiffness-lowering pipe section are not connected at the same time, so that the stiffness raising and lowering adjustment is independent and controllable, and has the advantages of simple control and safety and reliability.

[0011] Furthermore, the suspension bridge control circuit also includes an overload protection pipeline, which is connected to the rodless chamber of the suspension cylinder and the oil return port T of the oil tank, and the overload protection pipeline is equipped with an overload valve.

[0012] The beneficial effect of adopting the above-mentioned further solutions is that it helps protect the reliability and lifespan of the system and its components, and achieves overload protection.

[0013] Furthermore, it also includes a pressure feedback oil circuit, which is connected to the stiffness enhancement pipe section and the height enhancement pipe section respectively.

[0014] The beneficial effect of adopting the above-mentioned further scheme is that the actual load pressure is collected by the pressure feedback oil circuit, and automatic adjustment is achieved by using the hydraulic pressure signal.

[0015] Furthermore, the oil pump outlet P of the oil tank is connected to the stiffness enhancement pipe section and the height enhancement pipe section respectively through a filter.

[0016] The advantage of adopting the above-mentioned further solution is that it avoids the flow of metal particles or fine impurities caused by wear into the system, which helps to protect various valve components and pipelines in the system.

[0017] Furthermore, it also includes a control unit, wherein the damping valve is a bidirectional solenoid valve, and the height adjustment valve and stiffness adjustment valve are both unidirectional solenoid valves, and the damping valve, height adjustment valve and stiffness adjustment valve are controlled by the control unit.

[0018] The beneficial effect of adopting the above-mentioned further solution is that the damping valve, height adjustment valve and stiffness adjustment valve are controlled by the control unit, which has the advantages of simple structure, precise control and automatic adjustment.

[0019] Furthermore, there are two small-cavity accumulators, two large-cavity accumulators, and two suspension cylinders. The two suspension cylinders are connected in parallel. The oil chamber of each small-cavity accumulator is connected to the rod chamber of one suspension cylinder. The oil chamber of each large-cavity accumulator is connected to one end of the parallel connection of the rodless chambers of the two suspension cylinders through a suspension damping adjustment pipeline. Each suspension damping adjustment pipeline is equipped with a damping valve. One end of the parallel connection of the oil chambers of the two large-cavity accumulators is connected to one end of the parallel connection of the rodless chambers of the two suspension cylinders through a throttle valve.

[0020] The beneficial effect of adopting the above-mentioned further solution is that the suspension system can be adjusted independently by allowing the oil cylinders on both sides to exchange fluid with the accumulator according to the actual load changes on the left and right sides, thereby improving the stability and adaptability of the vehicle.

[0021] The present invention also provides a tractor to solve the above-mentioned technical problems, including the active independent suspension hydraulic control system as described above. The suspension damping adjustment pipeline is used to control the suspension system to switch between damping mode and non-damping mode. When the suspension system is in non-damping mode, the suspension damping adjustment pipeline is open, and when the suspension system is in damping mode, the suspension damping adjustment pipeline is closed. The suspension bridge control circuit is used to control the height change and stiffness change of the suspension bridge.

[0022] The beneficial effects of adopting the above-mentioned further solutions are that the suspension system can switch between damping mode and non-damping mode, and the suspension bridge circuit can adjust the height and stiffness simultaneously, so that the tractor can adapt to the changes in the terrain of field operations by adjusting the softness and hardness of the suspension system, adapt to multiple working conditions, reduce the wear and tear of parts, improve driving comfort, and help improve the quality of work and extend the service life.

[0023] Furthermore, when operating at transport speed, the suspension system is in undamped mode; when the suspension system is in its lowest or highest position, it is in damped mode; when the load is increased, the power take-off shaft is engaged, or both sides are braked, the suspension system is in damped mode.

[0024] The beneficial effects of adopting the above-mentioned further solutions are that, in undamped mode, the shock absorption and operational stability are improved; when the suspension is at its limit position, the suspension system is in damped mode, which can improve the vehicle's operating efficiency and driving stability, and extend the service life of the suspension system; when the load is lifted, the power output shaft is engaged, or both sides are braked, the damped mode increases the suspension rigidity and improves grip and traction. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an active independent suspension hydraulic control system according to the present invention; Figure 2This is a schematic diagram of an active independent suspension hydraulic control system in damping mode according to the present invention. Figure 3 This is a schematic diagram of an active independent suspension hydraulic control system in non-damped mode according to the present invention. Figure 4 This is a schematic diagram of the active independent suspension hydraulic control system of the present invention when the height of the suspended bridge is increased; Figure 5 This is a schematic diagram of the active independent suspension hydraulic control system of the present invention when the height of the suspended bridge decreases; Figure 6 This is a schematic diagram of the active independent suspension hydraulic control system of the present invention when the stiffness of the suspension bridge is improved; Figure 7 This is a schematic diagram of an active independent suspension hydraulic control system of the present invention when the stiffness of a suspended bridge decreases; Figure 8 This is a schematic diagram of an active independent suspension hydraulic control system under overload protection according to the present invention.

[0026] The attached diagram lists the components represented by each number as follows: 1. Suspension cylinder; 2. Large-cavity accumulator; 3. Small-cavity accumulator; 4. Damping valve; 51. Height increase valve; 52. Height decrease valve; 61. Stiffness increase valve; 62. Stiffness decrease valve; 7. Overload valve; 81. Throttle valve; 82. Pressure holding valve; 9. Filter; T, oil return port; LS, load feedback port; P, pump oil outlet. Detailed Implementation

[0027] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] Example 1 This embodiment provides an active independent suspension hydraulic control system, including a suspension cylinder 1, a large-cavity accumulator 2, and a small-cavity accumulator 3. A suspension damping adjustment pipeline is connected between the rodless chamber of the suspension cylinder 1 and the large-cavity accumulator 2. The suspension damping adjustment pipeline is equipped with a damping valve 4. The rod chamber of the suspension cylinder 1 is connected to the small-cavity accumulator 3. A suspension bridge control circuit is connected between the suspension cylinder 1 and the oil tank. The suspension bridge control circuit includes a height adjustment pipeline and a stiffness adjustment pipeline. The height adjustment pipeline and the stiffness adjustment pipeline are respectively equipped with a height adjustment valve and a stiffness adjustment valve.

[0029] In this way, the suspension damping adjustment pipeline adjusts the stiffness of the suspension system, and the suspension bridge control circuit adjusts the height and stiffness of the suspension bridge. The division of labor is clear, the reliability is high, and it can be adapted to different road conditions.

[0030] Specifically, in this embodiment, a variable pump is configured at the outlet of the oil tank. The outlet of the variable pump serves as the pumping outlet P of the oil tank, which is used to pump high-pressure oil into the suspension bridge control circuit. The suspension bridge control circuit sends the hydraulic oil back to the oil tank through the return port T of the oil tank.

[0031] Furthermore, it also includes a control unit. The damping valve 4 is a bidirectional solenoid valve, while the height adjustment valve and stiffness adjustment valve are both unidirectional solenoid valves. The damping valve 4, height adjustment valve, and stiffness adjustment valve are controlled by the control unit. Thus, the control unit controls the damping valve 4, height adjustment valve, and stiffness adjustment valve, which has the advantages of simple structure, precise control, and automatic adjustment.

[0032] In this embodiment, the suspension damping adjustment pipeline is used to control the stiffness of the suspension system. The damping valve 4 is set to automatic mode, and the control unit outputs a control signal to achieve automatic switching. That is, the damping valve 4 is controlled by the control unit. When the damping valve 4 is energized, it opens the suspension damping adjustment pipeline, increasing the oil exchange speed between the oil chamber of the large-cavity accumulator 2 and the rodless chamber of the suspension cylinder 1, resulting in a softer suspension system. When the damping valve 4 is de-energized, it closes the suspension damping adjustment pipeline, sealing off the oil between the oil chamber of the large-cavity accumulator 2 and the rodless chamber of the suspension cylinder 1, resulting in a stiffer suspension system. Of course, in other embodiments, the damping valve 4 can also open the suspension damping adjustment pipeline in the de-energized state and close it in the energized state.

[0033] The suspension bridge control circuit is used to control the height and stiffness changes of the suspension bridge. Specifically, the height adjustment pipeline includes a height lifting section and a height lowering section. The height lifting section is connected between the rodless chamber of the suspension cylinder 1 and the pump outlet P of the oil tank, and is equipped with a height lifting valve 51. The height lowering section is connected between the rodless chamber of the suspension cylinder 1 and the return port T of the oil tank, and is equipped with a height lowering valve 52. The height lifting section and the height lowering section are not simultaneously connected. This separation allows for independent control of the lifting and lowering actions, offering advantages such as simple control and high reliability.

[0034] In this embodiment, the suspension bridge is always within the midpoint range of 50% ± 5%. When the suspension bridge is outside this range, the height increase valve 51 and height decrease valve 52, controlled by the control unit, are activated to independently connect the height increase pipe section and the height decrease pipe section to change the height of the suspension bridge. At the same time, during vehicle operation, the suspension bridge can be raised to cross bumps or lowered to its lowest position for maintenance, and the height change of the suspension bridge can also be controlled manually.

[0035] The stiffness adjustment pipeline includes a stiffness lifting section and a stiffness lowering section. The stiffness lifting section connects the rod chamber of the suspension cylinder 1 to the pump outlet P of the oil tank and is equipped with a stiffness lifting valve 61. The stiffness lowering section connects the rod chamber of the suspension cylinder 1 to the return port T of the oil tank and is equipped with a stiffness lowering valve 62. The stiffness lifting section and the stiffness lowering section are not simultaneously connected. This separation allows for independent and controllable stiffness adjustment, offering advantages such as simple control and high reliability.

[0036] In this embodiment, the rod chamber of the suspension cylinder 1 is connected to the oil chamber of the small chamber accumulator 3. When the pump oil outlet P increases the oil volume between the rod chamber of the suspension cylinder 1 and the oil chamber of the small chamber accumulator 3 through the stiffness enhancement pipe section, the stiffness of the suspension bridge is enhanced. When the stiffness enhancement pipe section is connected to the oil return port T of the oil tank, the oil volume between the rod chamber of the suspension cylinder 1 and the oil chamber of the small chamber accumulator 3 is reduced, and the stiffness of the suspension bridge is reduced.

[0037] Typically, the pump outlet P of the oil tank is connected to the stiffness enhancement pipe section and the height enhancement pipe section via filter 9. This prevents metal particles or small impurities caused by wear from flowing into the system, thus protecting various valve components and pipelines in the system.

[0038] Furthermore, it also includes a pressure feedback oil circuit, which is connected to the stiffness enhancement pipe section and the height enhancement pipe section respectively. In this way, the actual load pressure is collected by the pressure feedback oil circuit, and automatic adjustment is achieved using the hydraulic pressure signal.

[0039] In this embodiment, one end of the pressure feedback oil circuit is connected to the load feedback port LS, and the other end has two branches. One branch is connected to the stiffness enhancement pipe section to provide feedback on the pressure signal of the stiffness enhancement pipe section, and the other branch is connected to the height enhancement pipe section to provide feedback on the pressure signal of the height enhancement pipe section. In this embodiment, each branch is equipped with a pressure holding valve 82. Typically, the internal flow of the pressure feedback oil circuit is extremely small and is not used to transport hydraulic oil; it is only used to transmit load changes. The pressure feedback oil circuit for load pressure feedback is existing technology.

[0040] Furthermore, the suspension bridge control circuit also includes an overload protection pipeline, which connects the rodless chamber of the suspension cylinder 1 to the oil return port T of the oil tank. The overload protection pipeline is equipped with an overload valve 7, which is a hydraulically controlled check valve. This design improves the reliability and lifespan of the protection system and its components, thus achieving overload protection.

[0041] Preferably, in the active independent suspension hydraulic control system, there are two small-cavity accumulators 3, two large-cavity accumulators 2, and two suspension cylinders 1. The two suspension cylinders 1 are connected in parallel, that is, the rod-side chambers of the two suspension cylinders 1 are connected, and the rodless chambers of the two suspension cylinders 1 are connected. The oil chamber of each small-cavity accumulator 3 is connected to the rod-side chamber of one suspension cylinder 1, and the oil chamber of each large-cavity accumulator 2 is connected to one end of the parallel connection of the rodless chambers of the two suspension cylinders 1 through a suspension damping adjustment pipeline. Each suspension damping adjustment pipeline is equipped with a damping valve 4. One end of the parallel connection of the oil chambers of the two large-cavity accumulators 2 is connected to the other end of the parallel connection of the rodless chambers of the two suspension cylinders 1 via a throttle valve 81. One suspension cylinder 1, along with its directly or indirectly connected suspension damping adjustment line, damping valve 4, one large-cavity accumulator 2, and one small-cavity accumulator 3, corresponds to the left side of the suspension system. The other suspension cylinder 1, along with its directly or indirectly connected suspension damping adjustment line, another damping valve 4, another large-cavity accumulator 2, and another small-cavity accumulator 3, corresponds to the right side of the suspension system. This allows the suspension system to adjust independently based on actual load changes on both sides, with each cylinder exchanging fluid with the accumulator, thus improving vehicle stability and adaptability.

[0042] Combination Figure 1-8 A specific connection method for an active independent suspension hydraulic control system is provided.

[0043] like Figure 1 As shown, the rodless chambers of the two suspension cylinders 1 are connected in parallel. The rodless chamber of each suspension cylinder 1 is connected to the oil chamber of a large-cavity accumulator 2 through a suspension damping adjustment pipeline. Each suspension damping adjustment pipeline is equipped with a damping valve 4. One end of the parallel connection of the oil chambers of the two large-cavity accumulators 2 is connected to the other end of the parallel connection of the two suspension cylinders 1 through a connecting pipeline. The connecting pipeline is equipped with a throttle valve 81. The rod chambers of the two suspension cylinders 1 are connected in parallel. The rod chamber of each suspension cylinder 1 is connected to the oil chamber of a small-cavity accumulator 3. The oil chambers of the two small-cavity accumulators 3 are connected in parallel.

[0044] like Figure 2 As shown, when the suspension system is in damping mode, the two damping valves 4 are de-energized and shut off, the suspension damping adjustment pipeline is shut off, and the oil chambers of the two large-chamber accumulators 2 are connected to the rodless chamber of the suspension cylinder 1 through connecting pipelines; as shown Figure 3 As shown, when the suspension system is in non-damped mode, the two damping valves 4 are energized, the suspension damping adjustment pipeline is open, and the connecting pipeline remains closed.

[0045] The pump oil outlet P of the variable pump is connected to the inlet of the filter 9. The outlet of the filter 9 is connected to two pipelines. One pipeline serves as a height lifting pipeline and is connected to the rodless chamber of each of the two suspension cylinders 1. The height lifting pipeline is equipped with a height lifting valve 51, which controls the opening and closing of the height lifting pipeline. A throttle valve 81 and a pressure holding valve 82 are sequentially installed on the pipeline between the height lifting valve 51 and the rodless chamber of the suspension cylinder 1. The other pipeline serves as a stiffness lifting pipeline and is connected to the rod chamber of each of the two suspension cylinders 1. The stiffness lifting pipeline is controlled by a stiffness lifting valve 61, which is sequentially installed on the pipeline between the stiffness lifting valve 61 and the rod chamber of the suspension cylinder 1. A throttle valve 81 and a pressure holding valve 82 are sequentially installed on the pipeline between the stiffness lifting valve 61 and the rod chamber of the suspension cylinder 1.

[0046] The oil return port T of the oil tank is connected to three pipelines. One pipeline serves as a stiffness reduction pipeline, connecting to the rod chambers of the two cylinders. The stiffness reduction pipeline is equipped with a stiffness reduction valve 62, which controls the opening and closing of the stiffness reduction pipeline. The remaining two pipelines serve as a height reduction pipeline and an overload protection pipeline, respectively. The height reduction pipeline is equipped with a height reduction valve 52, which controls the opening and closing of the height reduction pipeline. The overload protection pipeline is equipped with an overload valve 7, which controls the opening and closing of the overload protection pipeline.

[0047] One end of the pressure feedback oil circuit is connected to the load feedback port LS, and the other end forms two branches that are connected to the height enhancement pipe section and the stiffness enhancement pipe section, respectively. Figure 1 In the middle, two branches are respectively connected to the pipe section between the throttle valve 81 and the pressure holding valve 82, and each branch is equipped with a pressure holding valve 82.

[0048] Combination Figure 1 , 4 -8 provides the following details for adjusting the suspension bridge control loop in damping mode: like Figure 4 As shown, when the height of the suspension bridge is raised, the height raising valve 51 is energized. The oil flows from the pump oil outlet P through the filter 9, the height raising valve 51, the throttle valve 81, and the pressure holding valve 82 in sequence, and then enters the rodless chamber of the two suspension cylinders 1 and the oil chamber of the two large chamber accumulators 2. The pressure feedback oil circuit obtains the pressure signal from the height raising pipe section of the suspension bridge. At this time, the height lowering valve 52 is de-energized, keeping the height lowering pipe section closed.

[0049] like Figure 5 As shown, when the height of the suspension bridge decreases, the height reduction valve 52 is energized, and the oil flows out from the oil chamber of the large chamber accumulator 2 and the rodless chamber of the suspension cylinder 1. After passing through the height reduction valve 52, the oil returns to the oil tank from the oil return port T. At this time, the height increase valve 51 is de-energized, keeping the height increase pipe section closed.

[0050] like Figure 6As shown, when the stiffness of the suspension bridge increases, the stiffness increase valve 61 is energized. The oil flows from the pump oil outlet P through the filter 9, stiffness increase valve 61, throttle valve 81, and pressure holding valve 82 in sequence, and then enters the rod chambers of the two suspension cylinders 1 and the oil chambers of the two small chamber accumulators 3. The pressure feedback oil circuit obtains the pressure signal from the stiffness increase pipe section of the suspension bridge. At this time, the stiffness decrease valve 62 is de-energized, keeping the stiffness decrease pipe section closed.

[0051] like Figure 7 As shown, when the stiffness of the suspension bridge decreases, the stiffness reduction valve 62 is energized, and the oil flows out from the oil chamber of the small cavity accumulator 3 and the rod chamber of the suspension cylinder 1. After passing through the stiffness reduction valve 62, it returns to the oil tank from the oil return port T. At this time, the stiffness lifting valve 61 is de-energized, keeping the stiffness lifting pipe section closed.

[0052] like Figure 8 As shown, when passing an obstacle during driving, the load suddenly increases. In order to protect the reliability and lifespan of the system and its components, the overload valve 7 is guided through the overload circuit, allowing the oil to flow back from the rodless chamber of the large-cavity accumulator 2 and the suspension cylinder 1 to the oil tank, thereby relieving pressure and achieving the overload protection function.

[0053] Of course, the above-mentioned suspension bridge control loop can also be adjusted in non-damped mode.

[0054] Example 2 This embodiment provides a tractor, including the active independent suspension hydraulic control system described in the above embodiment. The suspension damping adjustment pipeline is used to control the suspension system to switch between damping mode and non-damping mode. When the suspension system is in non-damping mode, the damping valve 4 switches to have its inlet and outlet connected. When the suspension system is in damping mode, the damping valve 4 switches to have its inlet and outlet cut off. The suspension bridge control circuit is used to control the height and stiffness changes of the suspension bridge.

[0055] In this way, the suspension system can switch between damping mode and non-damping mode, and the suspension bridge control circuit can adjust the height and stiffness simultaneously, so that the tractor can adapt to the changes in the terrain of field operations by adjusting the softness and hardness of the suspension system, adapt to multiple working conditions, reduce the wear and tear of parts, improve driving comfort, and help improve the quality of work and extend service life.

[0056] Specifically, in undamped mode, the suspension system is the softest and has stronger shock absorption; in damped mode, the suspension system is stiffer.

[0057] When the tractor is operating at transport speed, the suspension system is in undamped mode, which improves shock absorption and operational stability. When the suspension system is in its lowest or highest position, it is in damped mode, which improves the vehicle's operating efficiency and driving stability, and extends the service life of the suspension system. When the load is lifted, the power take-off shaft is engaged, or both sides are braked, the suspension system is in damped mode. In these situations, the damped mode increases suspension rigidity, thereby improving grip and traction.

[0058] Furthermore, when the tractor uses the front or rear traction device to lift the load, the system can maintain the damping mode for a short time; preferably, the system maintains the damping mode for 5 seconds.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An active independent suspension hydraulic control system, characterized in that, The system includes a suspension cylinder (1), a large-cavity accumulator (2), and a small-cavity accumulator (3). The rodless cavity of the suspension cylinder (1) is connected to the large-cavity accumulator (2) via a suspension damping adjustment pipeline. The suspension damping adjustment pipeline is equipped with a damping valve (4). The rod cavity of the suspension cylinder (1) is connected to the small-cavity accumulator (3). The suspension cylinder (1) is connected to the oil tank via a suspension bridge control circuit. The suspension bridge control circuit includes a height adjustment pipeline and a stiffness adjustment pipeline. The height adjustment pipeline and the stiffness adjustment pipeline are respectively equipped with a height adjustment valve and a stiffness adjustment valve.

2. The active independent suspension hydraulic control system according to claim 1, characterized in that, The height adjustment pipeline includes a height lifting section and a height lowering section. The height lifting section is connected between the rodless chamber of the suspension cylinder (1) and the oil pump outlet P of the oil tank. The height lifting section is equipped with a height lifting valve (51). The height lowering section is connected between the rodless chamber of the suspension cylinder (1) and the oil return port T of the oil tank. The height lowering section is equipped with a height lowering valve (52). The height lifting section and the height lowering section are not connected at the same time.

3. The active independent suspension hydraulic control system according to claim 2, characterized in that, The stiffness adjustment pipeline includes a stiffness lifting section and a stiffness lowering section. The stiffness lifting section is connected between the rod chamber of the suspension cylinder (1) and the pump oil outlet P of the oil tank. The stiffness lifting section is equipped with a stiffness lifting valve (61). The stiffness lowering section is connected between the rod chamber of the suspension cylinder (1) and the return oil port T of the oil tank. The stiffness lowering section is equipped with a stiffness lowering valve (62). The stiffness lifting section and the stiffness lowering section are not connected at the same time.

4. The active independent suspension hydraulic control system according to claim 3, characterized in that, The suspension bridge control circuit also includes an overload protection pipeline, which is connected to the rodless chamber of the suspension cylinder (1) and the return port T of the oil tank. The overload protection pipeline is equipped with an overload valve (7).

5. The active independent suspension hydraulic control system according to claim 3, characterized in that, It also includes a pressure feedback oil circuit, which is connected to the stiffness enhancement pipe section and the height enhancement pipe section respectively.

6. The active independent suspension hydraulic control system according to claim 3, characterized in that, The oil tank's pump outlet P is connected to the stiffness enhancement pipe section and the height enhancement pipe section respectively through a filter (9).

7. The active independent suspension hydraulic control system according to claim 1, characterized in that, It also includes a control unit, wherein the damping valve (4) is a two-way solenoid valve, and the height adjustment valve and stiffness adjustment valve are both one-way solenoid valves. The damping valve (4), the height adjustment valve and the stiffness adjustment valve are controlled by the control unit.

8. The active independent suspension hydraulic control system according to claim 1, characterized in that, Two small cavity accumulators (3), two large cavity accumulators (2), and two suspension cylinders (1) are provided. The two suspension cylinders (1) are connected in parallel. The oil chamber of each small cavity accumulator (3) is connected to the rod chamber of one suspension cylinder (1). The oil chamber of each large cavity accumulator (2) is connected to one end of the rodless chamber of the two suspension cylinders (1) after being connected in parallel through a suspension damping adjustment pipeline. Each suspension damping adjustment pipeline is equipped with a damping valve (4). One end of the oil chambers of the two large cavity accumulators (2) after being connected in parallel is connected to one end of the rodless chamber of the two suspension cylinders (1) after being connected in parallel through a throttle valve (81).

9. A tractor, characterized in that, The system includes an active independent suspension hydraulic control system as described in any one of claims 1-8, wherein the suspension damping adjustment pipeline is used to control the suspension system to switch between damping mode and non-damping mode; when the suspension system is in non-damping mode, the damping valve (4) switches to its inlet and outlet connected; when the suspension system is in damping mode, the damping valve (4) switches to its inlet and outlet cut off; and the suspension bridge control circuit is used to control the height and stiffness changes of the suspension bridge.

10. A tractor according to claim 9, characterized in that, When operating at transport speed, the suspension system is in undamped mode; when the suspension system is at its lowest or highest position, it is in damped mode; when the load is increased, the power take-off shaft is engaged, or both sides are braked, the suspension system is in damped mode.

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