Closed center multi-way valve with merging function, hydraulic system and loader

Abstract

The application discloses a closed center multi-way valve with a flow combining function, a hydraulic system and a loader. An inlet of the multi-way valve is connected with inlets of a bucket joint, a boom joint and a tool joint in sequence. An inlet of a hydraulic control valve one is connected with a control end of the hydraulic control valve one, an inlet of the hydraulic control valve one and an inlet of a one-way valve one. An outlet of the one-way valve one is connected with an outlet of a one-way valve three and an inlet of the tool joint. An inlet of a hydraulic control valve two is connected with a spring cavity of the hydraulic control valve one, a control end of a tool joint compensator and a control end of the hydraulic control valve two. An outlet of the hydraulic control valve two is connected with an inlet of a one-way valve two. An outlet of the one-way valve two is connected with a control end of a boom joint compensator and a control end of a bucket joint compensator. The hydraulic system combined with the closed center multi-way valve and the quantitative gear pump can realize two options of standard flow and large flow. In the case that no action is performed, the flow of the flow combining can be normally returned to an oil tank, and the boom joint and the bucket joint can still work in the standard flow in the large flow state.

Description

Technical Field

[0001] This invention belongs to the field of loader technology, specifically relating to a closed-center multi-way valve with confluence function, a hydraulic system, and a loader. Background Technology

[0002] Loaders are typically equipped with various implements for operation, and different implements require different flow rates. Some implements require a large flow rate to operate, usually necessitating a high-flow-rate option in the loader's hydraulic system. For hydraulic systems with fixed displacement gear pumps and closed-center multi-way valves, under high-flow-rate operating conditions, if no action is taken, the combined flow cannot return to the oil tank normally, resulting in a persistent pressure buildup that cannot be resolved. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a closed-center multi-way valve with merging function, a hydraulic system, and a loader. The hydraulic system, which combines a fixed-displacement gear pump with a closed-center multi-way valve, can achieve both standard flow and high flow options. Furthermore, even without any action, the merged flow can return to the oil tank normally, and it can ensure that the boom and bucket linkages still operate at the standard flow rate even under high flow conditions.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, a closed-center multi-way valve with a merging function is provided, comprising: an oil inlet P1 for connecting to oil source one, the oil inlet P1 being sequentially connected to the inlets of the bucket assembly, boom assembly, and implement assembly, and a one-way valve three for unidirectional oil supply to the implement assembly being provided between the boom assembly and the implement assembly; an oil inlet P3 for connecting to oil source two, the oil inlet P3 being connected to the control end of hydraulic control valve one, the inlet of hydraulic control valve one, and the inlet of one-way valve one; the outlet of one-way valve one being connected to the outlet of one-way valve three and the inlet of the implement assembly; the inlet of hydraulic control valve two being connected to the spring chamber of hydraulic control valve one, the control end of the implement assembly compensator, and the control end of hydraulic control valve two; the outlet of hydraulic control valve two being connected to the inlet of one-way valve two; and the outlet of one-way valve two being connected to the control end of the boom assembly compensator and the control end of the bucket assembly compensator.

[0006] Furthermore, it also includes a damping valve, the inlet of which is connected to the spring chamber of hydraulic control valve one, the outlet of the damping valve, and the outlet of hydraulic control valve one is connected to the return port T2.

[0007] Furthermore, it also includes a differential relief valve, with its inlet connected to the oil inlet P1 and its outlet connected to the return oil port T2.

[0008] Secondly, a hydraulic system with a merging function is provided, wherein the hydraulic system is equipped with a closed-center multi-way valve with a merging function as described in the first aspect.

[0009] Furthermore, it also includes a gear pump 1 as an oil source, with its inlet connected to an oil tank and its outlet connected to an oil inlet P1; a gear pump 2 as an oil source, with its inlet connected to an oil tank and its outlet connected to an oil inlet P3; and an electric control valve, with its inlet connected to the outlet of gear pump 2, its outlet connected to an oil tank, and its control end connected to a high-flow button.

[0010] Furthermore, it also includes an overflow valve, the inlet of which is connected to the outlet of gear pump two, and the outlet is connected to the oil tank.

[0011] Furthermore, under standard flow operating conditions, the electric control valve is not energized and is in the connected position. The hydraulic oil output from gear pump two flows to the oil tank through the electric control valve, and the hydraulic oil output from gear pump one enters the closed-center multi-way valve with confluence function through the oil inlet P1. It then drives the bucket cylinder through the bucket linkage, the boom cylinder through the boom linkage, and the implement through the implement linkage.

[0012] Furthermore, when the high flow button is pressed but no action is taken or only the bucket and boom are moved, the electric control valve is energized and in the cut-off position. The hydraulic oil output from gear pump 2 reaches the inlet and control end of hydraulic control valve 1 through inlet P3. Hydraulic control valve 1 is in the connected position. The hydraulic oil output from gear pump 2 flows back to the oil tank through hydraulic control valve 1. The hydraulic oil output from gear pump 1 enters the closed-center multi-way valve with confluence function through inlet P1, and drives the bucket cylinder through the bucket linkage and the boom cylinder through the boom linkage.

[0013] Furthermore, when the high-flow button is pressed and the machine is operated, the hydraulic oil output by gear pump one enters the closed-center multi-way valve with confluence function through the oil inlet P1, and drives the bucket cylinder through the bucket linkage, the boom cylinder through the boom linkage, and the machine through the implement linkage. The hydraulic oil output by gear pump two reaches the inlet and control end of hydraulic control valve one through the oil inlet P3. The inlet of hydraulic control valve two receives the implement action signal fed back by the implement linkage and switches to the connected position. At the same time, the implement action signal fed back by the implement linkage reaches the spring chamber of hydraulic control valve one. Under the combined action of the spring force in the spring chamber and the implement action signal fed back by the implement linkage, hydraulic control valve one switches to the cut-off position. The hydraulic oil output by gear pump two enters the implement linkage through the oil inlet P3 and check valve one, and after merging with the hydraulic oil output by gear pump one, it is used to drive the work of the implement linkage.

[0014] Thirdly, a loader is provided, the loader being equipped with the hydraulic system with merging function described in the second aspect.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention connects the inlets of the bucket assembly, boom assembly, and implement assembly sequentially through the oil inlet P1. A one-way valve three for unidirectional oil supply to the implement assembly is provided between the boom assembly and the implement assembly. The oil inlet P3 is connected to the control end, inlet, and inlet of hydraulic control valve one. The outlet of one-way valve one is connected to the outlet of one-way valve three and the inlet of the implement assembly. The inlet of hydraulic control valve two is connected to the spring chamber of hydraulic control valve one, the control end of the implement assembly compensator, and the control end of hydraulic control valve two. The outlet of hydraulic control valve two is connected to the inlet of one-way valve two. The outlet of one-way valve two is connected to the control end of the boom assembly compensator and the control end of the bucket assembly compensator. This allows the hydraulic system of the fixed displacement gear pump and closed center multi-way valve combination to achieve both standard flow and high flow options. Even without any action, the combined flow can return to the oil tank normally, and it can ensure that the boom assembly and bucket assembly still operate at the standard flow rate under high flow conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a hydraulic system with merging function provided in an embodiment of the present invention;

[0017] In the diagram: 1. Gear pump one; 2. Closed-center multi-way valve; 21. Hydraulic control valve one; 22. Check valve one; 23. Check valve two; 24. Check valve three; 25. Hydraulic control valve two; 26. Damping valve; 27. Differential relief valve; 3. Gear pump two; 4. Electrically controlled valve; 5. Relief valve one; 6. Oil tank; 7. High flow rate button. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0019] Example 1

[0020] like Figure 1 As shown, a closed-center multi-way valve with merging function includes: an oil inlet P1 for connecting to oil source one, the oil inlet P1 being sequentially connected to the inlets of the bucket assembly, boom assembly, and implement assembly; a one-way valve 24 for unidirectional oil supply to the implement assembly is provided between the boom assembly and the implement assembly; an oil inlet P3 for connecting to oil source two, the oil inlet P3 being connected to the control end of hydraulic control valve 21, the inlet of hydraulic control valve 21, and the inlet of one-way valve 22; the outlet of one-way valve 22 being connected to the outlet of one-way valve 24 and the inlet of the implement assembly; the inlet of hydraulic control valve 25 being connected to the spring chamber of hydraulic control valve 21, the control end of the implement assembly compensator, and the control end of hydraulic control valve 25; the outlet of hydraulic control valve 25 being connected to the inlet of one-way valve 23; and the outlet of one-way valve 23 being connected to the control end of the boom assembly compensator and the control end of the bucket assembly compensator.

[0021] The inlet of damping valve 26 is connected to the spring chamber of hydraulic control valve 21, and the outlet of damping valve 26 and the outlet of hydraulic control valve 21 are connected to return port T2.

[0022] The inlet of the differential relief valve 27 is connected to the oil inlet port P1, and the outlet is connected to the oil return port T2.

[0023] Hydraulic control valve 1 21 is a hydraulically controlled two-position four-way valve, and hydraulic control valve 2 25 is a hydraulically controlled two-position four-way valve.

[0024] The inlet of gear pump 1, which serves as the oil source, draws oil through oil tank 6, and the outlet enters the inlet P1 of closed-center multi-way valve 2. The oil then returns to oil tank 6 through the return port T2 of closed-center multi-way valve 2 via differential relief valve 27.

[0025] The inlet of gear pump 2 3, which serves as the second oil source, draws oil through oil tank 6 and the outlet enters the inlet P3 of closed-center multi-way valve 2, which is connected to the inlet c1 of hydraulic control valve 1 21. The outlet c2 of hydraulic control valve 1 21 is connected to the return port T2 of closed-center multi-way valve 2.

[0026] The oil inlet P3 of the closed center multi-way valve 2 is connected to the inlet e1 of the one-way valve 22. The outlet e2 of the one-way valve 22 is connected to the oil inlet P4 of the closed center multi-way valve 2 and the outlet f2 of the one-way valve 24 of the boom linkage. The inlet f1 of the one-way valve 24 is connected to the return port T4 of the boom linkage.

[0027] The outlet g1 of check valve 23 is connected to the Ls feedback oil circuit of closed-center multi-way valve 2. The inlet g2 of check valve 23 is connected to the outlet d1 of hydraulic control valve 25. The inlet d2 of hydraulic control valve 25 is connected to the control end d3 of hydraulic control valve 25 and the spring cavity c3 of hydraulic control valve 1 21, and is also connected to the inlet q1 of damping valve 26. The outlet q2 of damping valve 26 is connected to the return port T2 of closed-center multi-way valve 2.

[0028] Example 2

[0029] Based on the closed-center multi-way valve with merging function described in Embodiment 1, this embodiment provides a hydraulic system with merging function.

[0030] The inlet b1 of the electrically controlled valve 4 (two-position two-way solenoid valve) is connected to the oil inlet P3 of the closed-center multi-way valve 2, and the outlet b2 is connected to the oil tank 6.

[0031] The inlet a1 of the overflow valve 5 is connected to the oil inlet P3 of the closed-center multi-way valve 2, and the outlet a2 is connected to the oil tank 6.

[0032] The high-flow button 7 controls the on / off power of the electric valve 4, thereby achieving the switching between standard flow and high flow.

[0033] The hydraulic system of the present invention with merging function has the following three working states after the vehicle engine is started.

[0034] First working state:

[0035] When the vehicle starts and operates at standard flow, the inlet of gear pump 1 draws oil through the oil tank 6, and the outlet enters the inlet P1 of the closed-center multi-way valve 2. Then, it returns to the oil tank 6 through the differential relief valve 27 and the return port T2 of the closed-center multi-way valve 2. At this time, the electronic control valve 4 is de-energized, and its inlet b1 and outlet b2 are connected. After the gear pump 3 draws oil through the oil tank 6, it returns to the oil tank 6 again at low pressure through the outlet b2 of the electronic control valve 4.

[0036] When the bucket and boom begin to move, the oil inlet P1 of the closed-center multi-way valve 2 enters the pressure oil control A and B compensators to realize the action. Since this control is based on the conventional technical principle of the closed-center multi-way valve, it will not be explained in detail here.

[0037] When the implement is in motion, the pressure oil of the closed-center multi-way valve 2 controls the C compensator to achieve the implement's motion. It should be noted that during implement motion, the C compensator can feed back the system pressure of the implement motion to the control terminal d3 of the hydraulic control valve 25, causing the hydraulic control valve 25 to switch. The feedback pressure signal from the implement connection opens the one-way valve 23, connecting its outlet g1 to its inlet g2, thereby transmitting pressure to the Ls feedback signal oil circuit of the bucket and boom connection, achieving a combined action of the bucket, boom, and implement. Since this control is based on the conventional technical principle of a closed-center multi-way valve, it will not be explained in detail here.

[0038] Second working state:

[0039] When the vehicle is started and the high flow button 7 is pressed, but no action is taken, or only the bucket and boom are moved, the electronic control valve 4 is energized and the inlet b1 to outlet b2 is closed.

[0040] The inlet of gear pump 1 draws oil through oil tank 6, and the outlet enters the oil inlet P1 of closed-center multi-way valve 2.

[0041] The inlet of gear pump 23 draws oil through oil tank 6, and the outlet enters the inlet P3 of closed-center multi-way valve 2. At this time, the spring chamber c3 of hydraulic control valve 121 is in a pressureless state, and the pressure generated by the control end c4 pushes hydraulic control valve 121 to the connected position, with inlet c1 and outlet c2 connected. The hydraulic oil of gear pump 23 returns to oil tank 6 through outlet c2 of hydraulic control valve 121.

[0042] The third type of work status:

[0043] When the vehicle is started, press the high flow button 7 and operate the machine. The inlet of gear pump 1 draws oil through the oil tank 6 and the outlet is connected to the oil inlet P1 of the closed center multi-way valve 2. At the same time, oil is supplied to the bucket, boom and machine assembly. At this time, the hydraulic oil in the oil inlet P1 enters the oil inlet P4 of the machine assembly through the outlet f2 of the one-way valve 24.

[0044] After the gear pump 23 draws oil from the oil tank 6, its outlet enters the inlet P3 of the closed-center multi-way valve 2. At this time, the pressure at the control terminal c4 of the hydraulic control valve 21 is the same as that at the inlet P1. The C compensator feeds back the system pressure of the implement's operation to the control terminal d3 of the hydraulic control valve 25, which can cause the hydraulic control valve 25 to switch, opening the check valve 23 so that its outlet g1 is connected to its inlet g2. This transmits the feedback pressure signal from the implement linkage to the bucket linkage and the boom linkage. At this time, the spring chamber of the hydraulic control valve 21... The pressure of c3 is greater than or equal to the pressure of control end c4. The pressure of spring chamber c3 plus spring pressure is greater than the pressure of control end c4. Therefore, the hydraulic control valve 21 is pushed to switch, and the inlet c1 and outlet c2 are disconnected. The hydraulic oil of gear pump 3 opens check valve 22 through the inlet e1 of check valve 22, and then connects with the inlet P4 of closed center multi-way valve 2 through the outlet e2 of check valve 22. At this time, gear pump 1 and gear pump 2 3 merge and enter the machine tool, achieving a large flow state.

[0045] At this time, the pressure at the inlet q1 of the damping valve is the same as the pressure at the spring chamber c3 of the hydraulic control valve 21. The hydraulic oil returns to the oil tank 6 through the outlet q2 of the damping valve 26. Because the damping port of the damping valve 26 is very small, it can ensure that the spring chamber c3 of the hydraulic control valve 21 always maintains a high pressure state when the machine is working together, thus improving the responsiveness of the confluence function.

[0046] Finally, it should be noted that the function of relief valve 5 is to limit the pressure of high-flow systems and protect the safety of components in high-flow systems.

[0047] This invention enables the combined flow rate of the equipment to be increased by only increasing the flow area of ​​the closed-center multi-way valve, thereby reducing the overall size and cost of the valve and making it easier to arrange. When the merging function is activated, if the equipment does not operate, the merging flow rate can return to the oil tank at a pressure lower than that of the differential relief valve, resulting in greater energy savings. This invention is equipped with a damping valve, which significantly improves the responsiveness of the initial state of merging activation.

[0048] This invention combines a fixed-displacement gear pump with a closed-center multi-way valve to enable the hydraulic system to offer both standard and high-flow options. Even without any operation, the combined flow returns normally to the oil tank, ensuring that the boom and bucket linkages operate at standard flow rates even under high-flow conditions. This expands the range of implements that can be mounted on the machine, improves its adaptability to various working conditions, and enhances its market competitiveness. It also makes a significant contribution to improving work efficiency and reducing labor intensity for users.

[0049] Example 3

[0050] Based on the closed-center multi-way valve with merging function described in Embodiment 1 and the hydraulic system with merging function described in Embodiment 2, this embodiment provides a loader, which is equipped with the closed-center multi-way valve with merging function described in Embodiment 1 or the hydraulic system with merging function described in Embodiment 2.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A closed-center multi-way valve with merging function, characterized in that, include: The oil inlet P1 is used to connect to the oil source one. The oil inlet P1 is connected to the inlet of the bucket assembly, boom assembly and implement assembly in sequence. A one-way valve three (24) is provided between the boom assembly and the implement assembly for one-way oil supply to the implement assembly. The oil inlet P3 is used to connect to the oil source 2. The oil inlet P3 is connected to the control end of the hydraulic control valve 1 (21), the inlet of the hydraulic control valve 1 (21), and the inlet of the check valve 1 (22). The outlet of the check valve 1 (22) is connected to the outlet of the check valve 3 (24) and the inlet of the tool connection. The inlet of hydraulic control valve 2 (25) is connected to the spring chamber of hydraulic control valve 1 (21), the control end of the machine tool compensator, and the control end of hydraulic control valve 2 (25). The outlet of hydraulic control valve 2 (25) is connected to the inlet of check valve 2 (23). The outlet of check valve 2 (23) is connected to the control end of boom compensator and the control end of bucket compensator. It also includes a damping valve (26), the inlet of which is connected to the spring chamber of the hydraulic control valve (21), the outlet of the damping valve (26) and the outlet of the hydraulic control valve (21) are connected to the return port T2; It also includes a differential relief valve (27), the inlet of which is connected to the oil inlet P1 and the outlet is connected to the return oil port T2.

2. A hydraulic system with a merging function, characterized in that, The hydraulic system is equipped with a closed-center multi-way valve with merging function as described in claim 1.

3. The hydraulic system with confluence function according to claim 2, characterized in that, It also includes a gear pump (1) as an oil source, with the inlet of the gear pump (1) connected to the oil tank (6) and the outlet connected to the oil inlet P1; Gear pump 2 (3) serves as the second oil source; the inlet of gear pump 2 (3) is connected to the oil tank (6), and the outlet is connected to the oil inlet P3; The inlet of the electric control valve (4) is connected to the outlet of the gear pump (3), the outlet is connected to the oil tank (6), and the control end is connected to the high flow button (7).

4. The hydraulic system with confluence function according to claim 3, characterized in that, It also includes overflow valve 1 (5), the inlet of overflow valve 1 (5) is connected to gear pump 2 (3) outlet, and the outlet is connected to oil tank (6).

5. The hydraulic system with confluence function according to claim 3 or 4, characterized in that, Under standard flow operating conditions, the electric control valve (4) is not energized and is in the connected position. The hydraulic oil output by the gear pump 2 (3) flows to the oil tank (6) through the electric control valve (4). The hydraulic oil output by the gear pump 1 (1) enters the closed center multi-way valve (2) with confluence function through the oil inlet P1, and drives the bucket cylinder through the bucket linkage, drives the boom cylinder through the boom linkage, and drives the implement through the implement linkage.

6. The hydraulic system with confluence function according to claim 3 or 4, characterized in that, When the high flow button (7) is pressed, but no action is taken or only the bucket and boom are moved, the electric control valve (4) is energized and is in the cut-off position. The hydraulic oil output by the gear pump (3) reaches the inlet and control end of the hydraulic control valve (21) through the inlet P3. The hydraulic control valve (21) is in the connected position. The hydraulic oil output by the gear pump (3) flows back to the oil tank (6) through the hydraulic control valve (21). The hydraulic oil output by the gear pump (1) enters the closed center multi-way valve (2) with the confluence function through the inlet P1, and drives the bucket cylinder through the bucket linkage and the boom cylinder through the boom linkage.

7. The hydraulic system with confluence function according to claim 3 or 4, characterized in that, When the high flow button (7) is pressed and the machine is operated, the hydraulic oil output by gear pump 1 (1) enters the closed center multi-way valve (2) with the confluence function through the oil inlet P1, and drives the bucket cylinder through the bucket linkage, drives the boom cylinder through the boom linkage, and drives the machine to work through the machine linkage. The hydraulic oil output by gear pump 2 (3) reaches the inlet and control end of hydraulic control valve 1 (21) through inlet P3. The inlet of hydraulic control valve 2 (25) receives the machine action signal fed back by the machine link and switches to the connected position. At the same time, the machine action signal fed back by the machine link reaches the spring chamber of hydraulic control valve 1 (21). Under the combined action of the spring force in the spring chamber and the machine action signal fed back by the machine link, hydraulic control valve 1 (21) switches to the cut-off position. The hydraulic oil output by gear pump 2 (3) enters the machine link through inlet P3 and check valve 1 (22), and merges with the hydraulic oil output by gear pump 1 (1) to drive the machine link to work.

8. A loader, characterized in that, The loader is equipped with a hydraulic system with merging function as described in any one of claims 2 to 7.

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