Flow distributor, multi-way valve, hydraulic system and working machine

Abstract

The present application relates to hydraulic technology, in order to solve the problem that the existing flow distributor is not coordinated in the composite action under the small flow operation state and the load pressure is not quickly established in response, the present application constructs a flow distributor, a multi-way valve, a variable hydraulic system and engineering machinery, wherein the flow distributor is provided with a spool cavity and an Ls flow supplement oil way in the valve rod, the spool cavity is arranged with a spool, the first end cavity chamber of the spool is communicated with the Pa / Pb cavity, and the second end cavity chamber of the spool is communicated with the Ls cavity; the two ends of the Ls flow supplement oil way are respectively communicated with the P1 cavity and the Ls cavity; the spool is configured to open the Ls flow supplement oil way when the pressure of the first end cavity chamber is greater than that of the second end cavity chamber, otherwise the Ls flow supplement oil way is closed. In the present application, the Ls flow supplement oil way is controlled to open and close by the pressure of the Pa / Pb cavity, the pressure of the Pa / Pb cavity is the real load pressure, and the Ls flow supplement oil way can be quickly opened to establish the load feedback pressure under the small flow operation state.

Description

Technical Field

[0001] This invention relates to hydraulic technology, and more specifically, to a flow distributor, a multi-way valve, a hydraulic system, and engineering machinery. Background Technology

[0002] In load-sensitive hydraulic systems, the variable displacement pump receives the load pressure signal from a multi-way valve and adjusts its displacement accordingly to input the corresponding flow rate. Multi-way valves typically include a multi-control master valve to control multiple hydraulic actuators for individual or combined actions.

[0003] Figure 1 Figure 2 An existing flow distributor is shown. Flow distributor 1 is connected downstream of control main valve 2. When control main valve 2 performs a reversing operation, pressure oil from the variable pump acts on the P1 chamber of flow distributor 1 through the valve core oil passage of control main valve 2, pushing the valve stem 20 of flow distributor 1 towards spring chamber 14. This connects P1 chamber 11 with Pa / Pb chamber 12. Pressure oil in Pa / Pb chamber 11 flows to the hydraulic actuator through working port A or B in the valve core oil passage of control main valve 2. After the valve stem 20 moves a certain distance towards spring chamber 14, P1 chamber 11 connects to Ls chamber 13 through the Ls flow supplement oil passage 21, providing flow to Ls chamber 13. Simultaneously, Ls chamber 13 connects to spring chamber 14, allowing the pressure in P1 chamber 11 and Ls chamber 14 to be compared on the valve stem 20.

[0004] In existing technology, when multiple hydraulic actuators controlled by a multi-way valve perform multi-link compound actions, the flow distributor 11 of each link compares the pressures of its respective P1 chamber 11 and Ls chamber 13. Based on the position of the valve stem 20 of each flow distributor 1, pressure compensation is achieved from P1 chamber 11 to Pa / Pb chamber 12, thus ensuring that the flow from P1 chamber 11 to each link is unaffected by the load. In the flow distributor 1, the position of the valve stem 20 is automatically adjusted by comparing the pressures of the spring chamber 14 and P1 chamber 11, thereby adjusting the valve opening between P1 chamber 11 and Pa / Pb chamber 12. An Ls flow replenishment oil passage 21 is provided on the valve stem 20 to replenish the flow to Ls chamber 13. The Ls flow replenishment oil passage 21 requires the valve stem 20 to move a certain distance to be open. When the flow rate input to P1 chamber 11 is small but the load is large, the displacement of valve stem 20 is also small. As a result, Ls flow supplement oil passage 21 may not be opened. The pressure of P1 chamber 11 cannot be fed back to Ls chamber 13 through Ls flow supplement oil passage 21 to control the flow rate in the main oil circuit of the main valve 2 to the actuator with a small load. The actuator with a large load has a small flow rate or even none. Specifically, this manifests as the inability to perform compound actions or the incoordination of compound actions when the whole engine is idling.

[0005] In addition, in the prior art, the P1 chamber 11 provides flow by connecting the Ls flow supplement oil passage 21 to the Ls chamber 13, which requires the valve stem 20 to move a large distance to the spring chamber, that is, the valve port between the P1 chamber 11 and the Pa / Pb chamber 12 to the corresponding position, which makes the Ls chamber 13 slow to establish pressure response. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that existing flow distributors have uncoordinated compound actions and slow response to load pressure establishment under low flow conditions. The present invention provides a flow distributor, a multi-way valve, a hydraulic system and engineering machinery.

[0007] The technical solution of this invention to achieve its objective is as follows: A flow distributor is provided, comprising a valve body and a valve stem disposed within the valve body; the valve body is provided with a P1 cavity, a Pa / Pb cavity, an Ls cavity, and a spring cavity; the P1 cavity is located at the first end of the valve stem, and the spring cavity is located at the second end of the valve stem and communicates with the Ls cavity; the valve stem is used to control the valve opening between the P1 cavity and the Pa / Pb cavity; a spring is disposed within the spring cavity, with its two ends respectively abutting against the second end of the valve stem and the valve body axially; The valve stem is provided with a valve core cavity and an Ls flow replenishment oil passage. The valve core is arranged in the valve core cavity. The first end chamber of the valve core is connected to the Pa / Pb cavity, and the second end chamber of the valve core is connected to the Ls cavity. The two ends of the Ls flow replenishment oil passage are connected to the P1 cavity and the Ls cavity, respectively. The valve core is configured to open the Ls flow replenishment oil passage when the pressure in its first end chamber is greater than the pressure in its second end chamber, and otherwise close the Ls flow replenishment oil passage.

[0008] In the flow distributor of the present invention, the first end of the valve core cavity is provided with a first screw plug that blocks and isolates the first end chamber of the valve core from the P1 cavity.

[0009] In the flow distributor of the present invention, a second screw plug is provided at the second end of the valve core cavity, and a damping hole is provided on the second screw plug to connect the second end cavity of the valve core with the spring cavity.

[0010] In the flow distributor of the present invention, the oil passage connecting the spring cavity and the Ls cavity is provided inside the valve stem.

[0011] In the flow distributor of the present invention, the valve body includes a plug that is directly opposite to the second end of the valve stem and threadedly connected to the main body of the valve body, and the spring abuts against the plug; the P1 cavity has a step that axially limits the first end of the valve stem.

[0012] The technical solution of the present invention to achieve its purpose is as follows: a multi-way valve is provided, including a multi-link control main valve, each of the control main valves is equipped with the aforementioned flow distributor, the P1 chamber and Pa / Pb chamber of each flow distributor are connected to the main oil circuit outlet and working oil circuit inlet in the corresponding control main valve, and the Ls chamber of each flow distributor is interconnected.

[0013] The technical solution of this invention to achieve its objective is as follows: A hydraulic system is provided, which has the aforementioned multi-way valve. Further, the hydraulic pump supplying oil to the multi-way valve in the hydraulic system is a variable displacement pump, and the Ls chambers 13 of each flow distributor 1 interconnected in the multi-way valve are connected to the load feedback port of the variable displacement pump via an oil circuit; or the hydraulic pump supplying oil to the multi-way valve in the hydraulic system is a fixed displacement pump.

[0014] The technical solution of the present invention to achieve its purpose is as follows: to provide an engineering machine having the aforementioned multi-way valve or the aforementioned hydraulic system.

[0015] Compared with the prior art, in this invention, the Ls flow replenishment oil passage is opened and closed by the pressure control of the Pa / Pb chamber. The pressure of the Pa / Pb chamber is the actual load pressure. Under low flow operation, the Ls flow replenishment oil passage can be opened quickly to establish load feedback pressure. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an existing flow distributor.

[0017] Figure 2 This is a schematic diagram of the principle of controlling the main valve and flow distributor in an existing multi-way valve.

[0018] Figure 3 This is a schematic diagram of the flow distributor of the present invention. Figure 1 .

[0019] Figure 4 This is a schematic diagram of the flow distributor of the present invention. Figure 2 .

[0020] Figure 5 This is a schematic diagram illustrating the principle of controlling the main valve and the flow distributor in the multi-way valve of the present invention.

[0021] Component names and serial numbers in the diagram: Flow distributor 1, control main valve 2.

[0022] Valve body 10, P1 chamber 11, Pa / Pb chamber 12, Ls chamber 13, spring chamber 14, plug 15, spring 16, connecting oil passage 17.

[0023] Valve stem 20, Ls flow replenishment oil passage 21, first screw plug 22, second screw plug 23, damping hole 24.

[0024] Valve core 40, valve core first end chamber 41, valve core second end chamber 42. Detailed Implementation

[0025] The specific implementation plan is described below with reference to the attached diagram.

[0026] like Figures 3 to 5 As shown, the flow distributor 1 includes a valve body 10 and a valve stem 20 arranged inside the valve body 10. The valve body 10 is provided with a P1 chamber 11, a Pa / Pb chamber 12, an Ls chamber 13, and a spring chamber 14. The P1 chamber 11 is located at the first end of the valve stem 20, and the spring chamber 14 is located at the second end of the valve stem 20 and communicates with the Ls chamber 13. The valve stem 20 is used to control the valve opening between the P1 chamber 11 and the Pa / Pb chamber 12. A spring 16 is provided in the spring chamber 14, with its two ends respectively abutting against the second end of the valve stem 20 and the valve body 10 axially. The valve stem 20 is provided with a valve core cavity and an Ls flow replenishment oil passage 21. A valve core 40 is arranged in the valve core cavity, which divides the valve core cavity into a first end chamber 41 and a second end chamber 42. The first end chamber 41 is connected to the Pa / Pb cavity 12, and the second end chamber 42 is connected to the Ls cavity 13. The two ends of the Ls flow replenishment oil passage 21 are connected to the P1 cavity 11 and the Ls cavity 13, respectively. The valve core 40 is configured to open the Ls flow replenishment oil passage 21 when the pressure in its first end chamber 41 is greater than the pressure in its second end chamber 42, and otherwise close the Ls flow replenishment oil passage 21.

[0027] like Figure 3 As shown, the valve core cavity is formed by installing a first screw plug and a second screw plug at both ends of the shaft hole in the valve stem, respectively. The second screw plug has a damping hole, which connects to the spring cavity. The first screw plug is used to seal and isolate the first end chamber of the valve core from the P1 cavity. The connecting oil passage 17, which connects the spring cavity 14 and the Ls cavity 13, is provided in the valve stem 20. The second end chamber 42 of the valve core is connected to the Ls cavity 13 through the spring cavity 14 and the connecting oil passage 17.

[0028] The valve body 10 includes a plug 15 that is directly opposite to the second end of the valve stem 20 and is threadedly connected to the main body of the valve body 10, and a spring 16 abuts against the plug 15; the P1 cavity 11 has a step that axially limits the first end of the valve stem 20.

[0029] This embodiment provides a multi-way valve, such as Figure 5 As shown, the multi-way valve includes a multi-control main valve 2 (only one control main valve is shown in the figure). Each control main valve 2 is equipped with the aforementioned flow distributor 1. The P1 chamber 11 of each flow distributor 1 is connected to the main oil circuit outlet in the corresponding control main valve. The Pa / Pb chamber 12 of each flow distributor 1 is connected to the working oil circuit inlet. The Ls chamber 13 of each flow distributor 1 is interconnected.

[0030] In the multi-way valve, the P port of each control main valve 2 is connected to the variable pump. When the valve stem of the control main valve 2 moves and reverses direction, the P port of the control main valve 2 is connected to the main oil circuit outlet through the main oil circuit controlled by the valve stem of the control main valve. The working oil circuit inlet is connected to port A or port B through the working oil circuit controlled by the valve stem of the control main valve. Port A and port B are connected to the hydraulic actuator. The hydraulic oil flows from the variable pump through the P port of the control main valve, the main oil circuit outlet, P1 chamber 11, Pa / Pb chamber 12, the working oil circuit inlet, port A or port B to the hydraulic actuator.

[0031] An embodiment provides a hydraulic system having the aforementioned multi-way valve. The P port of the multi-way valve is connected to the pump port of a variable pump. The Ls chambers 13 of each flow distributor 1 in the multi-way valve are connected to the load feedback port of the variable pump through an oil circuit. The variable pump controls its displacement according to the load pressure feedback from the Ls chambers 13, thereby providing a suitable flow rate for the hydraulic system.

[0032] An embodiment provides a hydraulic system having the aforementioned multi-way valve. The P port of the multi-way valve is connected to the pump port of a hydraulic pump, which can be a fixed displacement pump. The Ls chambers 13 of each flow distributor 1 in the multi-way valve are interconnected. The hydraulic system is a fixed displacement system. In a fixed displacement hydraulic system, the Ls chambers 13 of each interconnected flow distributor 1 are sealed with screw plugs at their Ls ports connected to the outside, and no load feedback pressure is provided to the hydraulic pump.

[0033] An embodiment provides an engineering machine having the aforementioned multi-way valve or the aforementioned hydraulic system. This engineering machine may be a loader, excavator, etc.

[0034] In this implementation, after the main control valve 2 reverses, the P port of the main control valve enters the P1 chamber through the main oil circuit outlet, generating pressure in the P1 chamber 11. When the pressure in the P1 chamber 11 is greater than the pressure in the Ls chamber 13, the valve stem 20 moves towards the second end. At this time, the P1 chamber 11 is connected to the Pa / Pb chamber 12. The oil in the P1 chamber 11 flows to the Pa / Pb chamber 12, and the oil in the Pa / Pb chamber 12 flows to the working oil circuit inlet of the main control valve, flowing to the hydraulic actuator through port A or port B. Simultaneously, the oil in the Pa / Pb chamber 12 flows to the first end chamber 41 of the valve core, and the pressure in the Ls chamber 13 acts on the second end of the valve core 40 through the second end chamber 42 of the valve core, realizing the pressure comparison between the Ls chamber 13 and the Pa / Pb chamber 12. When the pressure in the Pa / Pb chamber 12 is greater than the pressure in the Ls chamber 13, the valve core 40 moves towards the second end, and the Ls flow supplement oil passage 21 is opened. Figure 4As shown, the pressure in Ls chamber 13 is higher than the pressure before Ls flow supplement oil passage 21 is opened. The increased pressure in Ls chamber 13 acts on the flow distributors of other lines through the pipeline. The valve stem 20 in the other flow distributor 1 moves under the increased pressure in Ls chamber 13 and reaches equilibrium again. During the process of reaching equilibrium, the valve opening of its P1 chamber 11 and Pa / Pb chamber 12 is reduced, thereby reducing the flow input of the main control valve of other lines with smaller loads.

[0035] In this embodiment, the connection of the Ls flow supplement oil passage 21 is determined by comparing the pressures of Ls chamber 12 and Pa / Pb chamber 11. Whether the load-sensitive compensation system is established depends on the pressure (load pressure) of Pa / Pb chamber 12 in the flow distributor 1, and is independent of the valve opening between P1 chamber 11 and Pa / Pb chamber 12. Therefore, the valve stem 20 does not need to move to a predetermined position before responding, allowing the load-sensitive compensation system to respond quickly. Since the establishment of the load-sensitive compensation system is independent of the valve opening between P1 chamber 11 and Pa / Pb chamber 12, it can be established even with very low flow rates. This enables multiple actuators to perform compound actions regardless of the pump's output flow rate.

Claims

1. A flow distributor, comprising a valve body and a valve stem disposed within the valve body; the valve body is provided with a P1 chamber, a Pa / Pb chamber, an Ls chamber, and a spring chamber, the P1 chamber being located at a first end of the valve stem, the spring chamber being located at a second end of the valve stem and communicating with the Ls chamber, the valve stem being used to control the valve opening degree between the P1 chamber and the Pa / Pb chamber; a spring is disposed within the spring chamber, with its two ends respectively abutting against the second end of the valve stem and the valve body axially; characterized in that: The valve stem is provided with a valve core cavity and an Ls flow replenishment oil passage. The valve core cavity is arranged with a valve core. The first end chamber of the valve core is connected to the Pa / Pb cavity. The second end of the valve core cavity is provided with a second screw plug. The second screw plug is provided with a damping hole connecting the second end chamber of the valve core to the spring cavity. The two ends of the Ls flow replenishment oil passage are connected to the P1 cavity and the Ls cavity, respectively. The valve core is configured to open the Ls flow replenishment oil passage when the pressure in the first end chamber of the valve core is greater than the pressure in the second end chamber of the valve core, and otherwise close the Ls flow replenishment oil passage.

2. The flow distributor according to claim 1, characterized in that, The first end of the valve core cavity is provided with a first screw plug that seals and isolates the first end chamber of the valve core from the P1 cavity.

3. The flow distributor according to claim 1 or 2, characterized in that, The oil passage connecting the spring cavity and the Ls cavity is located inside the valve stem.

4. The flow distributor according to claim 1, characterized in that, The valve body includes a plug that is directly opposite the second end of the valve stem and is threadedly connected to the main body of the valve body, and the spring abuts against the plug; the P1 cavity has a step that axially limits the first end of the valve stem.

5. A multi-way valve, comprising a multi-control main valve, characterized in that, Each of the control main valves is equipped with a flow distributor as described in any one of claims 1 to 4. The P1 chamber and Pa / Pb chamber of each flow distributor are connected to the main oil circuit outlet and working oil circuit inlet of the valve core oil circuit of the corresponding control main valve, and the Ls chamber of each flow distributor is connected to each other.

6. A hydraulic system, characterized in that, It has the multi-way valve as described in claim 5.

7. The hydraulic system according to claim 6, characterized in that, The hydraulic pump supplying oil to the multi-way valve in the hydraulic system is a variable pump. The Ls chambers of the interconnected flow distributors in the multi-way valve are connected to the load feedback port of the variable pump through an oil circuit.

8. The hydraulic system according to claim 6, characterized in that, The hydraulic pump supplying oil to the multi-way valve in the hydraulic system is a fixed displacement pump.

9. An engineering machinery, characterized in that, It has a multi-way valve as described in claim 5 or a hydraulic system as described in any one of claims 6 to 8.

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