Large-flow load-sensitive multi-way valve and control system thereof

Abstract

The invention discloses a high-flow load-sensitive multi-way valve and a control system thereof. The problems that an existing loader control system is unreliable in compound action and large in impact during confluence are solved. The system comprises a large-flow load-sensitive multi-way valve; the valve body is provided with a first oil inlet, a feedback oil way, an oil return port, a first working oil port and a second working oil port; the second oil inlet is connected with the first pump and used for feeding oil; the first oil inlet and the second oil inlet are matched with each other and convey oil to the first reversing valve and / or the second reversing valve; the anti-impact valve comprises an unloading valve element, a first damper and a second damper. The second oil inlet is connected with the oil return port through the unloading valve core; pressure oil of the first damping oil outlet, pressure oil of the second damping oil outlet and set elastic force of the unloading valve element spring cavity interact to control an opening of the unloading valve element. The invention has the advantages of simple structure, reliable action, long service life and the like.

Description

Technical Field

[0001] The present invention relates to an engineering vehicle control system, and particularly to a large-flow load-sensitive multi-way valve and its control system. Background Art

[0002] Engineering vehicles are the main force in a construction project. Thanks to their emergence, the progress of construction projects has doubled, greatly reducing the manpower. Existing engineering vehicles include loaders, bulldozers, rollers, etc. Taking loaders as an example, as an important part of construction machinery, the overall energy-saving performance of loaders is of great significance for the entire construction machinery industry to transform towards a low-carbon and environmentally friendly economy. Energy-saving and high-efficiency have become an important development direction in the loader industry. Moreover, with the full implementation of the "National IV" standard and the rapid development of construction machinery, a large number of construction machinery vehicles are exported. Customers have higher and higher requirements for the overall efficiency, controllability, and energy-saving performance of the machines. However, the lack and immaturity of domestic key core hydraulic components, especially large-flow load-sensitive multi-way valves, have long relied on imports. The main engine factories have long been troubled by high component costs and long supply cycles.

[0003] Currently, most existing loaders adopt open-center multi-way valves, and the principle is as Figure 1 、 2 shown. For the existing open-center multi-way valves, the boom working connection and the bucket working connection are directly connected. When performing combined actions, the movement of the rotation working connection is unreliable. For the control system using this multi-way valve, the structure is very complex. When two pumps are in confluence, the structure is unreliable, and the impact is relatively large when the flow rate is too large. Although it has the advantages of simple system structure and low price, there are still several problems: on the one hand, the working efficiency is low, the overflow loss is large, and the heat generation is large, resulting in low working efficiency and consuming more fuel for loading and unloading the same amount of materials; on the other hand, the instantaneous pressure impact is relatively large; thirdly, there is no compensation function, and the flow rate is greatly affected by the load and the inlet pressure, and the combined action effect of the boom and the bucket is not good. Summary of the Invention

[0004] To solve the problems of unreliable combined actions and large impact during confluence in the existing loader control system in the background art, the present invention provides a large-flow load-sensitive multi-way valve and its control system.

[0005] The technical solution of the present invention is: a large-flow load-sensitive multi-way valve, including a valve body, and the valve body is provided with a first oil inlet, a feedback oil circuit, an oil return port, a first working oil port, and a second working oil port; further including: A first reversing valve, which is arranged in the valve body and slidably cooperates with the valve body, and the first reversing valve is correspondingly arranged with the first working oil port; A second reversing valve, which is arranged in the valve body and slidably cooperates with the valve body, and the second reversing valve is correspondingly arranged with the second working oil port; The second oil inlet is connected to the first pump for oil intake; the first oil inlet and the second oil inlet cooperate with each other and convey oil to the first reversing valve and / or the second reversing valve; The shock-resistant valve includes a pressure-relief valve core, a first damper, and a second damper; the second oil inlet is connected to the oil return port through the pressure-relief valve core, the pressure oil of the second oil inlet is connected to the control chamber of the pressure-relief valve core through the first damper, and the pressure oil of the feedback oil circuit is connected to the spring chamber of the pressure-relief valve core through the second damper; the pressure oil at the oil outlet of the first damper, the pressure oil at the oil outlet of the second damper, and the set elastic force of the spring chamber of the pressure-relief valve core interact to control the opening of the pressure-relief valve core.

[0006] As a further improvement of the present invention, a third reversing valve is further included, and the third reversing valve is arranged between the second oil inlet and the first damper.

[0007] As a further improvement of the present invention, the feedback oil circuit is connected to the control chamber of the third reversing valve, and the pressure oil of the feedback oil circuit and the set elastic force of the third reversing valve cooperate with each other to control the opening of the third reversing valve.

[0008] As a further improvement of the present invention, it further includes: A first pressure compensator, the pressure oil of the second oil inlet and / or the first oil inlet is connected to the first pressure compensator through the first reversing valve, and the oil outlet of the first pressure compensator is respectively connected to the feedback oil circuit and, after passing through the first reversing valve, to the first working oil port; A second pressure compensator, the pressure oil of the second oil inlet and / or the first oil inlet is connected to the second pressure compensator through the second reversing valve, and the oil outlet of the second pressure compensator is respectively connected to the feedback oil circuit and, after passing through the second reversing valve, to the second working oil port.

[0009] As a further improvement of the present invention, a compensation check valve is further included, which is arranged between the oil outlet of the first pressure compensator and the feedback oil circuit and between the oil outlet of the second pressure compensator and the feedback oil circuit, and is used to pick up the feedback oil pressure of the feedback oil circuit.

[0010] As a further improvement of the present invention, an overload valve is further included, which is arranged between the second oil port and the oil return port and is used for load overload protection.

[0011] As a further improvement of the present invention, it further includes: A main relief valve, which is used to receive the pressure oil of the first oil inlet and / or the second oil inlet, and the oil outlet of the main relief valve is connected to the oil return port, and is used to improve the safety performance of the system; A feedback relief valve, which is arranged between the feedback oil circuit and the oil return port and is used for overload protection.

[0012] As a further improvement of the present invention, the feedback oil circuit includes a first feedback channel and a second feedback channel. The feedback overflow valve is provided on the second feedback channel. A third damper is provided between the first feedback channel and the second feedback channel. A fixed flow valve is provided on the first feedback channel, and the fixed flow valve is connected to the oil return port.

[0013] As a further improvement of the present invention, it further includes an extension connection. A fourth reversing valve and a third working oil port are provided on the extension connection. The extension connection is provided on the valve body and is detachably connected to the valve body. The fourth reversing valve is slidably engaged with the extension connection. The fourth reversing valve receives the pressure oil from the first oil inlet and / or the second oil inlet and is correspondingly arranged with the third working oil port.

[0014] A control system includes: The above-mentioned large-flow load-sensitive multi-way valve; A second pump for providing pressure oil; A steering power source for controlling the steering of the product; A steering priority valve is connected to the second pump and is respectively connected to the steering power source and the first oil inlet, and is used for preferentially supplying oil to the steering power source; A selection shuttle valve selects the oil at the steering priority valve and the feedback oil of the feedback oil circuit and is connected to the second pump for controlling the output of the second pump; A pilot control oil source for providing a pilot oil source.

[0015] The beneficial effects of the present invention are as follows: An impact-resistant valve is provided to protect the system from pressure shocks and extend the service life of components. When the system suddenly encounters huge loads, rapid movements, or frequent telescoping of the oil cylinder and other working conditions, the variable pump has not yet responded in time to the load change to change the output pressure, and the impact-resistant valve can respond quickly to eliminate the pressure peak. The present invention also has the advantages of simple structure, reliable operation, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 is a schematic structural diagram of a multi-way valve of an existing loader.

[0017] Attached Figure 2 is a schematic structural diagram of a control system of an existing loader.

[0018] Attached Figure 3 is a schematic structural diagram of an embodiment of the present invention.

[0019] Attached Figure 4 is a schematic hydraulic principle diagram of a loader control system according to an embodiment of the present invention.

[0020] Attached Figure 5 is a schematic hydraulic principle diagram of a multi-way valve according to an embodiment of the present invention.

[0021] In the figure, 1 is the valve body; 11 is the first working oil port; 12 is the second working oil port; 2 is the first reversing valve; 3 is the second reversing valve; 4 is the shock-resistant valve; 41 is the unloading spool; 42 is the first damper; 43 is the second damper; 44 is the third reversing valve; 51 is the first pressure compensator; 52 is the second pressure compensator; 53 is the compensating check valve; 54 is the overload valve; 6 is the main relief valve; 71 is the feedback relief valve; 72 is the first feedback channel; 73 is the second feedback channel; 74 is the third damper; 75 is the constant flow valve; 8 is the extended connection; 81 is the fourth reversing valve; 82 is the third working oil port; 91 is the second pump; 92 is the steering power source; 93 is the steering priority valve; 94 is the selection shuttle valve; 95 is the pilot control oil source; 96 is the first pump; 97 is the multi-way valve; P1 is the first oil inlet; P2 is the second oil inlet; LS is the feedback oil circuit; T is the oil return port. Detailed implementation mode

[0022] The embodiments of the present invention will be further described below with reference to the accompanying drawings: From Figure 3 Combined with Figures 4-5 As shown, a large-flow load-sensitive multi-way valve includes a valve body 1, and the valve body is provided with a first oil inlet P1, a feedback oil circuit LS, an oil return port T, a first working oil port 11 and a second working oil port 12; it also includes: The first reversing valve 2 is arranged in the valve body and slidably cooperates with the valve body, and the first reversing valve is correspondingly arranged with the first working oil port; The second reversing valve 3 is arranged in the valve body and slidably cooperates with the valve body, and the second reversing valve is correspondingly arranged with the second working oil port; The second oil inlet P2 is connected to the first pump 96 for oil inlet; the first oil inlet and the second oil inlet cooperate with each other and convey oil to the first reversing valve and / or the second reversing valve; The impact-resistant valve 4 includes a pressure-relief valve core 41, a first damper 42, and a second damper 43. The second oil inlet is connected to the oil return port through the pressure-relief valve core. The pressure oil at the second oil inlet is connected to the control chamber of the pressure-relief valve core through the first damper. The pressure oil in the feedback oil circuit is connected to the spring chamber of the pressure-relief valve core through the second damper. The pressure oil at the oil outlet of the first damper, the pressure oil at the oil outlet of the second damper, and the set elastic force of the spring chamber of the pressure-relief valve core interact to control the opening of the pressure-relief valve core. The beneficial effects of the present invention are that an impact-resistant valve is provided to protect the system from pressure shocks and extend the service life of components. When the system suddenly encounters huge loads, rapid movements, or frequent telescoping of the oil cylinder and other working conditions, the variable pump has not yet responded in time to the load change to change the output pressure. The impact-resistant valve can respond quickly and eliminate the pressure peak. The present invention also has the advantages of simple structure, reliable operation, and long service life. The impact-resistant valve integrated in the multi-way valve of the present invention has a low-pressure unloading function, making the system more energy-efficient. At the same time, it also has high-pressure overflow, improving the safety performance of the product. This system greatly reduces the number of components and can reduce the cost by about 40% compared with the existing system.

[0023] The present invention also includes a third reversing valve 44, and the third reversing valve is arranged between the second oil inlet and the first damper. Specifically, the feedback oil circuit is connected to the control chamber of the third reversing valve, and the pressure oil in the feedback oil circuit and the set elastic force of the third reversing valve cooperate with each other to control the opening of the third reversing valve. In the present invention, P2 is connected to a fixed-displacement gear pump, and P1 is connected to the EF port of the variable pump of the steering system. Confluence can be achieved on the premise of ensuring priority steering. That is, when not steering, the variable pump picks up the load pressure through the shuttle valve, and the oil of the variable pump enters P1 through the priority valve stem and confluences with the gear pump, greatly increasing the flow rate of the working system and improving the working efficiency of the whole machine. The first-stage integrated impact-resistant valve has a relatively low set pressure (about 10 - 15 bar) and is used as a three-way flow valve to ensure the pressure difference at the outlet of the fixed-displacement pump. When not working, it unloads at low pressure. When connected to a variable pump, the set pressure of the impact-resistant valve is slightly higher than the differential pressure valve of the load-sensitive pump (about 30 bar - 35 bar). After the spool of the working-stage valve quickly returns to the middle position, the pressure oil at the P port is sealed. The pump variable mechanism requires time to respond. According to tests, it is found that setting the impact-resistant valve can eliminate the pressure peak from the pump outlet to the valve, eliminate hydraulic shocks, and extend the service life of the pump and valve. In the present invention, the bridge circuit composed of the pressure-relief valve core, the first damper, and the second damper can be designed according to the vehicle working conditions. The dynamic response effect of the working structure movement is good, it can be accurately controlled, and the adaptation range is wide.

[0024] The present invention also includes: A first pressure compensator 51. The pressure oil at the second oil inlet and / or the first oil inlet is connected to the first pressure compensator through a first reversing valve. The oil outlet of the first pressure compensator is respectively connected to the feedback oil circuit and, after passing through the first reversing valve, to the first working oil port. A second pressure compensator 52, the pressure oil at the second oil inlet and / or the first oil inlet is connected to the second pressure compensator through a second reversing valve, and the oil outlet of the second pressure compensator is respectively connected to the feedback oil circuit and, after passing through the second reversing valve, to the second working oil port. Specifically, it further includes a compensation check valve 53, which is provided between the oil outlet of the first pressure compensator and the feedback oil circuit and between the oil outlet of the second pressure compensator and the feedback oil circuit, for picking up the feedback oil pressure of the feedback oil circuit. The multi-way valve of the present invention has load-sensing control, good fine-tuning performance, can realize the simultaneous operation of multiple actuating structures, and the flow rate is independent of the load. In the present invention, each spool valve (the first reversing valve, the second reversing valve, the fourth reversing valve) can be separately set for flow rate and pressure, and can achieve fast and precise control of each control mechanism, improving the smoothness and reliability of the operation of the whole machine. Each compensation spool valve (pressure compensator) of the multi-way valve of the present invention has the function of a check valve (compensation check valve), preventing the load from sliding down during operation. When the bucket and the boom perform a combined action, when there is a difference in the load pressures of the two actions, the joint with a higher load pressure demand will slide down due to insufficient pressure to overcome the load; the compensation spool valve has the function of a check valve, which can ensure that the compensation spool valve can only open when the pressure at the P port is greater than the load demand pressure, ensuring the safety of the loader during operation. During the combined action, the compensation check valve picks up the pressure, and both the boom and the bucket will feedback the load pressure to the pump. The pump will pick up the highest pressure and then adjust the swash plate angle to control the output. Without this check valve, the high-pressure oil will press the compensator at the low-load end to death, and the compensator cannot be opened.

[0025] The present invention further includes an overload valve 54, which is provided between the second oil port and the oil return port for load overload protection. Usually, the overload valve is set in the working connection of the bucket rotation to prevent the bucket from rotating beyond the set limit, improving the safety performance of the system and the operator. In fact, in the present invention, a load-holding check valve for the large chamber of the boom is also provided to prevent the boom from automatically retracting; and a make-up check valve for the small chamber of the boom is provided for oil make-up.

[0026] The present invention further includes: A main relief valve 6, which is used to receive the pressure oil at the first oil inlet and / or the second oil inlet, and the oil outlet of the main relief valve is connected to the oil return port, for improving the safety performance of the system; A feedback relief valve 71, which is provided between the feedback oil circuit and the oil return port for overload protection. Specifically, the feedback oil circuit LS includes a first feedback channel 72 and a second feedback channel 73, the feedback relief valve is provided on the second feedback channel, a third damper 74 is provided between the first feedback channel and the second feedback channel, and a fixed flow valve 75 is provided on the first feedback channel, and the fixed flow valve is connected to the oil return port. The main safety valve (main relief valve) and the load protection relief valve (feedback relief valve) can effectively protect against overload and improve the safety of the system.

[0027] The present invention further includes an extension joint 8, on which a fourth reversing valve 81 and a third working oil port 82 are provided; the extension joint is arranged on the valve body and is detachably connected to the valve body, the fourth reversing valve is slidably matched with the extension joint, and the fourth reversing valve receives the pressure oil from the first oil inlet and / or the second oil inlet and is correspondingly arranged with the third working oil port. This multi-way valve can be extended as needed and is used in cooperation with a vehicle. Usually, the extension joint is used as a working joint for a tool.

[0028] A control system includes: The large-flow load-sensitive multi-way valve 97 described above; A second pump 91 for providing pressure oil; A steering power source 92 for controlling the steering of the product; A steering priority valve 93, connected to the second pump and respectively connected to the steering power source and the first oil inlet, for preferentially supplying oil to the steering power source; A selection shuttle valve 94, selecting the oil at the steering priority valve and the feedback oil in the feedback oil circuit and connecting it to the second pump, for controlling the output of the second pump; A pilot control oil source 95 for providing a pilot oil source. An efficient and energy-saving hydraulic system is disclosed in the present invention. The steering system is a load-sensitive variable system, and the working system is a fixed-displacement pump system. That is, the first pump is a fixed-displacement pump, and the second pump is a variable pump. Specifically, the second pump is a load-sensitive variable pump. In the hydraulic system of the present invention, an anti-shock valve is arranged at the outlet of the variable pump to protect the system from pressure shocks and extend the service life of components. When the cylinders in the steering joint or the working joint suddenly encounter huge loads, move quickly, or the cylinders extend and retract frequently, etc., the variable pump has not yet responded to the load change in time to change the output pressure, and the anti-shock valve can respond quickly to eliminate the pressure peak. The hydraulic system of the present invention has a load-sensitive pump with a pressure cut-off function for steering. When the cylinder reaches the limit working condition, the fixed-displacement pump unloads first, and then the pump performs pressure cut-off. Without redundant flow loss under the condition of meeting the system pressure and flow requirements, the entire system has high efficiency. Combined with the main valve with post-compensation, the compound action is good and the control accuracy is high. The hydraulic system of the present invention solves the problem of poor compound action effect between the boom and the bucket, realizes perfect compound of multiple actions, and improves the operation efficiency; the hydraulic system of the present invention has a simple structure and low maintenance cost, and has a large cost advantage; the multi-way valve and the hydraulic system of the present invention can be applied to engineering vehicles such as loaders, bulldozers, and road rollers.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, in the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0031] All technicians should note that although the present invention has been described according to the above specific embodiments, the inventive concept of the present invention is not limited to this invention alone. Any modification using the inventive concept of the present invention will be included in the scope of protection of the patent right of the present invention.

Claims

1. A large-flow load-sensitive multi-way valve, comprising a valve body, characterized in that: The described valve body is provided with a first oil inlet, a feedback oil circuit, an oil return port, a first working oil port, and a second working oil port; further comprising: A first reversing valve, disposed within the valve body and slidably engaged with the valve body, and the first reversing valve is correspondingly arranged with the first working oil port; A second reversing valve, disposed within the valve body and slidably engaged with the valve body, and the second reversing valve is correspondingly arranged with the second working oil port; A second oil inlet, connected to a first pump for oil inlet; the first oil inlet and the second oil inlet cooperate with each other and convey oil to the first reversing valve and / or the second reversing valve; An impact-resistant valve, including a unloading valve core, a first damper, and a second damper; the second oil inlet is connected to the oil return port through the unloading valve core, the pressure oil of the second oil inlet is connected to the control chamber of the unloading valve core through the first damper, and the pressure oil of the feedback oil circuit is connected to the spring chamber of the unloading valve core through the second damper; the pressure oil at the outlet of the first damper, the pressure oil at the outlet of the second damper, and the set elastic force of the spring chamber of the unloading valve core interact to control the opening of the unloading valve core.

2. The large-flow load-sensitive multi-way valve according to claim 1, characterized in that Further comprising a third reversing valve, which is disposed between the second oil inlet and the first damper.

3. The large-flow load-sensitive multi-way valve according to claim 2, characterized in that The feedback oil circuit is connected to the control chamber of the third reversing valve, and the pressure oil of the feedback oil circuit and the set elastic force of the third reversing valve cooperate with each other to control the opening of the third reversing valve.

4. The large-flow load-sensitive multi-way valve according to claim 1, wherein Further comprising: A first pressure compensator, the pressure oil of the second oil inlet and / or the first oil inlet is connected to the first pressure compensator through the first reversing valve, and the outlet of the first pressure compensator is respectively connected to the feedback oil circuit and, after passing through the first reversing valve, to the first working oil port; A second pressure compensator, the pressure oil of the second oil inlet and / or the first oil inlet is connected to the second pressure compensator through the second reversing valve, and the outlet of the second pressure compensator is respectively connected to the feedback oil circuit and, after passing through the second reversing valve, to the second working oil port.

5. The large-flow load-sensitive multi-way valve according to claim 4, wherein Further comprising compensating check valves, which are disposed between the outlet of the first pressure compensator and the feedback oil circuit and between the outlet of the second pressure compensator and the feedback oil circuit, for picking up the feedback oil pressure of the feedback oil circuit.

6. The large-flow load-sensitive multi-way valve according to claim 1, characterized in that Further comprising an overload valve, which is disposed between the second oil port and the oil return port for load overload protection.

7. The large-flow load-sensitive multi-way valve according to claim 1, characterized in that Further comprising: A main relief valve, for receiving the pressure oil of the first oil inlet and / or the second oil inlet, and the outlet of the main relief valve is connected to the oil return port for improving the safety performance of the system; A feedback relief valve, disposed between the feedback oil circuit and the oil return port for overload protection.

8. The large-flow load-sensitive multi-way valve according to claim 7, characterized in that The feedback oil circuit includes a first feedback channel and a second feedback channel, the feedback relief valve is disposed on the second feedback channel, a third damper is provided between the first feedback channel and the second feedback channel, a fixed flow valve is provided on the first feedback channel, and the fixed flow valve is connected to the oil return port.

9. The large-flow load-sensitive multi-way valve according to claim 1, wherein Further comprising an extended connection, on which a fourth reversing valve and a third working oil port are provided; the extended connection is disposed on the valve body and is detachably connected to the valve body; The fourth reversing valve is slidably engaged with the extended connection, and the fourth reversing valve receives the pressure oil of the first oil inlet and / or the second oil inlet and is correspondingly arranged with the third working oil port.

10. A control system, characterized in that: Including: Adopt the large-flow load-sensitive multi-way valve described in any one of claims 1-9; A second pump for providing pressure oil; A steering power source for controlling the steering of the product; A steering priority valve connected to the second pump and respectively connected to the steering power source and the first oil inlet, for preferentially supplying oil to the steering power source; A selection shuttle valve for selecting the oil at the steering priority valve and the feedback oil in the feedback oil circuit and connecting it to the second pump, for controlling the output of the second pump; A pilot control oil source for providing a pilot oil source.

Images