Open center multi-way valve, reversing link and valve body thereof

Abstract

The invention provides an open center multi-way valve, a reversing link and a valve body of the reversing link, and is suitable for the technical field of hydraulic pressure. The multi-way valve achieves accurate control over flow and pressure through main valve element proportion control and LS valve element pressure difference adjustment, and a variable pump does not need to be relied on. A reversing linkage main valve element is provided with a left position, a middle position and a right position, the opening degree is dynamically adjusted in cooperation with an LS valve element, the flow of a low-pressure execution unit is limited, and energy waste in a non-working state is reduced through the design of a backpressure channel. The multi-way valve effectively solves the problem of composite action flow control, improves the energy efficiency and response speed of a hydraulic system, and is suitable for high-requirement scenes such as electric engineering machinery.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, and in particular to an open-center multi-way valve, a reversing coupling, and its valve body. Background Technology

[0002] Nowadays, electric-powered construction machinery is rapidly squeezing out traditional oil-powered loaders, and electric construction machinery is gaining an increasingly larger market share. The hydraulic control systems of electric-powered construction machinery have also undergone significant changes. For example, the hydraulic oil source in these machines is now an electric motor driving a hydraulic pump. The motor's speed can be adjusted in real time according to actual operational needs. In other words, the output oil volume of the hydraulic pump can be adjusted by changing the motor's speed. Traditionally, hydraulic equipment driven by gasoline / diesel engines achieved adjustable hydraulic pump output by controlling the displacement of a variable displacement pump through throttle and a series of hydraulic signals. However, variable displacement pumps are very expensive and have a relatively high failure rate.

[0003] Currently, variable displacement pumps are used in electric construction machinery on the market. This configuration can meet the needs of existing working conditions, but the system simultaneously controls the flow rate by regulating the motor speed and the displacement of the variable displacement pump. Having two different flow rate regulation devices simultaneously is considered an over-configuration and doesn't address the high cost of variable displacement pumps. If a fixed displacement pump is used in conjunction with a load-sensitive valve, the following problems also arise: To improve response speed, the motor driving the hydraulic pump in construction machinery typically has a standby speed of around 800 rpm, resulting in a considerable output flow rate. This output flow cannot directly return to the oil, causing continuous energy loss and raising the temperature of the hydraulic system.

[0004] When a fixed displacement pump is used in conjunction with an open-center multi-way valve, if there are multiple parallel actuators in the hydraulic system, there is a situation where the higher the pressure, the lower the flow rate. This phenomenon makes it difficult to control the flow rate in engineering machinery, especially when there are compound actions, resulting in operational difficulties at the actuator end. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an open-center multi-way valve, a reversing coupling, and its valve body.

[0006] The technical solution adopted in this invention is: A type of open-center multi-way valve reversing coupling includes a main valve core. Its valve body has a P port for external connection to the inlet oil line, a T port for external connection to the return oil line, and working oil ports A and B. The main valve core is proportionally controlled and has left, center, and right positions. Transition ports P1 and P2 are provided between the P port and ports A / B. An LS valve core is located between ports P1 and P2, and the LS valve core has left, center, and right positions. Pilot oil passages on both sides of the LS valve core are respectively connected to port P1 and the system... The LS oil circuit is controlled proportionally by the pressure of the P1 port and the system LS oil circuit. The oil inlet of the LS valve core is connected to the P1 port, and the two oil outlets are connected to the system LS oil circuit and the P2 port, respectively. The oil outlet and oil inlet of the system LS oil circuit are connected through the oil passage inside the valve core, and the opening between the oil outlet and oil inlet of the P2 port is controlled by the displacement of the LS valve core. The main valve core is equipped with hydraulic pilot oil circuits a1 and b1 at both ends to control the valve core switching.

[0007] Furthermore, the main valve core is also equipped with back pressure passages P3 and P4, and the opening of the oil ports from P3 to P4 is controlled by the displacement of the main valve core.

[0008] Furthermore, a one-way valve is provided between the oil outlet of the LS valve core and the P2 port, allowing one-way flow from the oil outlet of the LS valve core to the P2 port.

[0009] An open-center multi-way valve includes several open-center multi-way valve reversing couplings arranged in parallel and a first relief valve. The first relief valve is an equal-differential relief valve, whose inlet is connected to the system pressure oil circuit, its two pilot ports are respectively connected to the system pressure oil circuit and the LS oil circuit, and its outlet is used for oil discharge.

[0010] Furthermore, it includes an LS constant flow valve, with one oil port connected to the LS oil circuit and the other oil port used for oil drainage.

[0011] Furthermore, it also includes a second relief valve, whose inlet is connected to the LS oil circuit and whose outlet is used for oil drainage.

[0012] Furthermore, the pilot oil sources on both sides of the main valve core are connected via an electro-proportional pressure reducing valve or a high-speed switching valve.

[0013] A center-opening multi-way valve reversing valve body includes a valve body with a first valve hole inside. A main valve core is installed in the first valve hole. An oil inlet chamber is located at the center of the first valve hole. A first working oil port transition chamber and a second working oil port transition chamber are respectively located on both sides of the oil inlet chamber. The first working oil port transition chamber is connected to the first working oil port, and the second working oil port transition chamber is connected to the second working oil port. A first return oil transition chamber and a second return oil transition chamber are located outside the first working oil port transition chamber and outside the second working oil port transition chamber, respectively. The first and second return oil transition chambers are connected to the return oil chamber. The main valve core has a shoulder. The sliding of the main valve core allows the first working oil port transition chamber and the second working oil port transition chamber to communicate with each other. The working oil port transition chamber is connected to or blocked by the oil chambers on both sides. The valve body also has an inlet oil passage and a return oil passage running through it. The inlet oil passage and the return oil passage are perpendicular to the first valve hole. The inlet oil passage is connected to the inlet oil chamber, and the return oil passage is connected to the return oil chamber. The valve body also has a second through hole and a third valve hole. The second through hole is parallel to the first valve hole, and the third valve hole is perpendicular to and intersects the second through hole. A first transition chamber is provided on one side of the inlet oil chamber, and the first transition chamber is connected to the bottom of the third valve hole. The valve body also has an LS oil passage parallel to the inlet oil passage and the return oil passage. The LS oil passage runs through the valve body and intersects with the third valve hole. An LS valve core is provided inside the third valve hole. The LS valve core slides within the third valve hole, controlling the distance between the bottom of the third valve hole and the second through hole. The LS valve core has an internal oil passage with openings on both sides located at the bottom and top of the LS valve core, respectively. The top opening position matches the position of the LS oil passage. A third transition chamber is provided between the first transition chamber and the first working oil port transition chamber, and a fourth transition chamber is provided between the oil inlet chamber and the second working oil port transition chamber. The third and fourth transition chambers are respectively connected to the second through hole. The main valve core has a first shoulder, a second shoulder, a third shoulder, a fourth shoulder, and a fifth shoulder. The first shoulder is located in the middle of the main valve core, between the oil inlet chamber and the first transition chamber. The first shoulder has a first throttling groove and a second throttling groove on both sides, thereby controlling the oil inlet chamber to the fifth through hole. The opening of a transition cavity; the second shoulder and the third shoulder are located on either side of the first shoulder; the second shoulder is located between the first transition cavity, the third transition cavity, and the first working oil port transition cavity, controlling the opening and closing of the third transition cavity and the first working oil port transition cavity, while ensuring that the first transition cavity and the third transition cavity are not connected; the third shoulder is located between the fourth transition cavity and the second working oil port transition cavity, controlling the opening and closing of the fourth transition cavity and the second working oil port transition cavity; the fourth shoulder is located outside the second shoulder and is located at the first return oil transition cavity, controlling the opening and closing of the first return oil transition cavity; the fifth shoulder is located outside the third shoulder and is located at the second return oil transition cavity, controlling the opening and closing of the second return oil transition cavity.

[0014] Furthermore, a first back pressure chamber and a second back pressure chamber are provided between the oil inlet chamber and the fourth transition chamber. The first back pressure chamber and the second back pressure chamber are respectively connected to the system pressure oil circuit and the return oil circuit. A sixth shoulder is provided between the third shoulder and the first shoulder in the main valve core. The sixth shoulder is located between the second back pressure chamber and the first back pressure chamber. The right side of the third shoulder and the left side of the sixth shoulder control the connection and disconnection between the second back pressure chamber and the first back pressure chamber. The sixth shoulder also ensures that the oil inlet chamber and the first back pressure chamber are not connected.

[0015] Furthermore, a first one-way valve core and a second one-way valve core are respectively installed on both sides of the second through hole located on the third valve hole, so that the oil in the second through hole located on both sides of the third valve hole can flow unidirectionally to the third transition chamber and the fourth transition chamber.

[0016] Furthermore, a third overflow valve core and a fourth overflow valve core are respectively provided on the outside of the first one-way valve core and the second one-way valve core in the second through hole. The inlets of the third overflow valve core and the fourth overflow valve core are respectively connected to the oil circuit of the working oil port of the first working oil port transition chamber and the second working oil port transition chamber. The outlets of the third overflow valve core and the fourth overflow valve core are respectively connected to the first return oil transition chamber and the second return oil transition chamber.

[0017] A valve body for an open-center multi-way valve that realizes the function of an open-center multi-way valve includes a first valve body and a last valve body installed on both sides of several open-center multi-way valve reversing valve bodies. The first valve body is connected to the outlet of the hydraulic pump and is provided with an oil port that connects to the oil inlet channel and LS oil circuit of the open-center multi-way valve reversing valve body. The last valve body is connected to the oil tank and is provided with an oil port that connects to the oil return channel of the open-center multi-way valve reversing valve body. The first or last valve body has an equal-gradient relief valve hole.

[0018] The open-center multi-way valve of this invention controls the opening degree of the LS valve core by controlling the pressure difference between the multi-way valve and the system load-sensitive oil circuit, thereby limiting the flow rate of the low-pressure actuator. The differential relief valve maintains a constant pressure difference between the load-sensitive oil circuit and the supply line. Combined with the throttling orifice formed between the throttling groove and the valve body when the directional valve core reverses, this allows for precise flow and pressure control without relying on a variable displacement pump or load-sensitive pump. Furthermore, by setting a back pressure chamber whose opening degree is controlled by the main valve core, the pressure of the multi-way valve only increases during operation, significantly reducing energy waste during non-operational periods. Through the above structure, combined with an electronic control scheme to control the motor speed for flow control, the multi-way valve is highly compatible with the motor-motor-displacement pump system. Attached Figure Description

[0019] Figure 1 This is a longitudinal cross-sectional view of the multi-way valve reversing linkage of the present invention; Figure 2 This is a longitudinal cross-sectional view of the multi-way valve switching valve body of the present invention; Figure 3 This is a structural diagram of the main valve core of the multi-way valve reversing linkage of the present invention; Figure 4 This is a structural diagram of the LS valve core of the multi-way valve reversing linkage of the present invention; Figure 5 This is a schematic diagram of the multi-way valve structure of the present invention; Figure 6 This is a schematic diagram of the multi-way valve reversing connection principle of the present invention; Figure 7 This is a schematic diagram of the multi-way valve of the present invention; Figure 8 This is a schematic diagram of the functional structure of the Q-type slide valve with multi-way valve reversing linkage of the present invention; Figure 9 This is a schematic diagram of the functional structure of the multi-way valve reversing Y-type slide valve of the present invention; Figure 10 This is a schematic diagram of the pressure source principle of the multi-way valve matched with the dual quantitative pump of the present invention; Figure 11 This is a schematic diagram of the multi-way valve matched with a dual quantitative pump pressure source structure of the present invention; Figure 12 This is a schematic diagram of the pressure source principle of the multi-way valve matching fixed displacement pump-variable displacement pump of the present invention.

[0020] In the diagram: 1 - Main valve body, 11-First valve port, 110-Oil inlet chamber, 111-First transition chamber, 112-First back pressure chamber, 113-Third transition chamber, 114-Fourth transition chamber, 115-First working oil port transition chamber, 116-Second working oil port transition chamber, 117-First return oil transition chamber, 118-Second return oil transition chamber, 119-Second back pressure chamber 12-Second through hole, 121-First one-way valve hole, 122-First one-way passage cavity, 123-Second one-way valve hole, 124-Second one-way passage cavity, 125-Third overflow valve hole, 126-Fourth overflow valve hole, 127-Third overflow valve outlet cavity, 128-Fourth overflow valve outlet cavity. 13-Third valve port, 131-LS transition chamber 14 - First oil passage, 15 - Second oil passage, 16 - Third oil passage, 17 - Fourth oil passage, 18 - Fifth oil passage, 19 - Sixth oil passage, 20 - Seventh oil passage 2-Main valve core, 21-First shoulder, 22-Second shoulder, 23-Third shoulder, 24-Fourth shoulder, 25-Fifth shoulder, 26-Sixth shoulder 211 - First throttling channel, 212 - Second intercepting channel 31-First working oil port, 32-Second working oil port, 33-Return oil chamber 41-Inlet oil passage, 42-Return oil passage, 43-LS oil passage 5-LS valve core, 50-inner oil passage, 51-first check valve core, 52-second check valve core, 53-third relief valve core, 54-fourth relief valve core.

[0021] 6-First relief valve, 7-Second relief valve, 8-LS constant flow valve. Detailed Implementation

[0022] like Figure 1-2 As shown, a center-opening multi-way valve reversing valve body includes a valve body (1), with a first valve hole (11) and a second through hole (12) arranged laterally inside the valve body (1). Below the first valve hole (11) is a return oil chamber (33), and the top of the valve body (1) has a first working oil port (31) and a second working oil port (32). From left to right, the first valve hole (11) is provided with a second return oil transition chamber (118), a second working oil port transition chamber (116), a fourth transition chamber (114), a second back pressure chamber (119), a first back pressure chamber (112), an oil inlet chamber (110), a first transition chamber (111), a third transition chamber (113), a first working oil port transition chamber (115), and a first return oil transition chamber (117). The second through hole (12) is, from left to right, the fourth overflow valve hole 126, the fourth overflow valve outlet cavity 128, the second one-way valve hole 123, the second one-way passage cavity 124, the first one-way passage cavity 122, the first one-way valve hole 121, the third overflow valve outlet cavity 127, and the third overflow valve hole 125.

[0023] The valve body (1) is also provided with a longitudinal third valve hole (13), which is located at the top of the valve body (1) and intersects with the second through hole (12) located between the first unidirectional passage cavity 122 and the second unidirectional passage cavity 124. The bottom of the third valve hole (13) is provided with an LS transition cavity 131.

[0024] The valve body (1) is also provided with an oil inlet passage (41), an oil return passage (42), and an LS oil passage (43) that penetrate the valve body and are perpendicular to the first valve hole (11), the second through hole (12), and the third valve hole (13). The oil inlet passage (41) is alternately connected to the oil inlet chamber (110), the oil return passage (42) is alternately connected to the oil return chamber (33), and the LS oil passage (43) is alternately connected to the LS transition chamber 131.

[0025] A first oil passage 14 connects the first transition chamber (111) and the LS transition chamber 131. A second oil passage 15 connects the third transition chamber (113) and the first one-way passage 122. A third oil passage 16 connects the fourth transition chamber (114) and the second one-way passage 124. A fourth oil passage 17 connects the first working port transition chamber (115) and the first working port (31). The fourth oil passage 17 is partially interleaved with the first one-way valve hole 121 and the third overflow valve outlet 127 in the second through hole (12). A fifth oil passage 18 connects the second working port transition chamber (116) and the second working port (32). The fifth oil passage 18 is partially interleaved with the fourth overflow valve outlet 128 and the second one-way valve hole 123 in the second through hole (12). The bottom of the first return oil transition chamber (117) and the second return oil transition chamber (118) are connected to the return oil chamber (33). The sixth oil passage 19 is opened between the first return oil transition chamber (117) and the third overflow valve outlet chamber 127. The seventh oil passage 20 is opened between the second return oil transition chamber (118) and the fourth overflow valve outlet chamber 128.

[0026] like Figure 3 As shown, the main valve core (2) is provided with a fifth shoulder (25), a third shoulder (23), a sixth shoulder (26), a first shoulder (21), a second shoulder (22), and a fourth shoulder (24) from left to right. The first shoulder (21) has a first throttling groove (211) on the left side and a second throttling groove (212) on the right side.

[0027] like Figure 1-3As shown, after the main valve core (2) is installed into the first valve hole (11), the first shoulder (21) is located between the oil inlet chamber (110) and the first transition chamber (111), controlling the opening degree from the oil inlet chamber (110) to the first transition chamber (111). The second shoulder (22) is located between the first transition chamber (111), the third transition chamber (113), and the first working oil port transition chamber (115), controlling the opening and closing of the third transition chamber (113) and the first working oil port transition chamber (115), while keeping the first transition chamber (111) and the third transition chamber (113) disconnected; the third shoulder (23) is located between the fourth transition chamber (114) and the second working oil port transition chamber (116), controlling the opening and closing of the fourth transition chamber (114) and the second working oil port transition chamber (116). The fourth shoulder (24) is located at the first return oil transition chamber (117), controlling the opening and closing of the first return oil transition chamber (117). The fifth shoulder (25) is located at the second return oil transition chamber (118) and controls the opening and closing of the second return oil transition chamber (118). The sixth shoulder (26) is located between the second back pressure chamber (119) and the first back pressure chamber (112). The right side of the third shoulder (23) and the left side of the sixth shoulder (26) control the connection and disconnection between the second back pressure chamber (119) and the first back pressure chamber (112), while ensuring that the oil inlet chamber (110) and the first back pressure chamber (112) are not connected. Figure 5 As shown, the first back pressure chamber (112) and the second back pressure chamber (119) are respectively connected to the external oil circuit. The two external oil circuits are in opposite directions, so that the back pressure chambers of the multiple series multi-way valves form a series passage. The external oil circuit of the back pressure chamber on one side of the multiple series multi-way valves is connected to the system pressure oil circuit, and the external oil circuit of the back pressure valve on the other side is connected to the return oil circuit.

[0028] like Figure 1 , 2 As shown in Figure 4, an LS valve core (5) is installed in the third valve hole (13), and a screw plug is installed on the top. The LS valve core (5) has an inner oil passage (50). One end of the inner oil passage (50) is located on the bottom surface of the LS valve core (5), and the other end is located on the top side of the LS valve core (5). The position of the inner oil passage (50) at the top side of the LS valve core (5) satisfies the following: when the LS valve core (5) is lifted up and the LS transition cavity 131 is connected to the second through hole (12), the inner oil passage (50) at the top side of the LS valve core (5) is connected to the LS oil passage.

[0029] like Figure 1As shown, one-way valve cores are installed in the first one-way valve hole 121 and the second one-way valve hole 123 to enable one-way flow from the second through hole (12) to the first one-way flow chamber 122 and the second one-way flow chamber 124. Overflow valve cores are installed in the third overflow valve hole 125 and the fourth overflow valve hole 126 to allow the oil in the fourth oil passage 17 to flow into the return oil chamber (33) through the third overflow valve outlet 127 and the first return oil transition chamber (117), and to allow the oil in the fifth oil passage 18 to flow into the return oil chamber (33) through the fourth overflow valve outlet 128, the seventh oil passage 20 and the second return oil transition chamber (118).

[0030] When the actuator controlled by the multi-way valve operates, it is through, for example... Figure 1 The pilot control or manual control shown causes the main valve core to slide, connecting the oil inlet chamber (110) and the first transition chamber (111). Depending on the sliding distance, the first throttling groove (211) or the second intercepting groove 212 on the first shoulder will generate different openings, controlling the speed of the corresponding execution unit. If the main valve core moves to the left, the third transition chamber (113) and the first working oil port transition chamber (115) will be connected, and the second working oil port transition chamber (116) and the second return oil transition chamber (118) will be connected; if the main valve core moves to the right, the fourth transition chamber (114) and the second working oil port transition chamber (116) will be connected, and the first working oil port transition chamber (115) and the first return oil transition chamber (117) will be connected.

[0031] The system pressure oil enters the LS transition chamber 131 through the first oil passage 14, pushes the LS valve core 131 upward, and makes the pressure oil enter the second through hole 2. Then, it passes through the one-way valve on one side and finally flows out from the working oil port on that side. The return oil flows into the return oil chamber (33) through the working oil port on the other side and finally flows into the system return oil circuit. During this process, pressurized oil flows into the load-sensitive oil circuit of the system through the inner oil passage (50) and the LS oil passage (43). When multiple multi-way valves work at the same time, the oil pressure in the load-sensitive oil circuit of the system is the oil pressure of the highest execution pressure. At this time, the oil in the LS oil passage (43) of the multi-way valve with low oil pressure flows back, reducing the opening of the LS valve core (5) or even closing it. After the opening of the LS valve core (5) decreases or closes, the oil pressure in the LS transition chamber 131 gradually accumulates and increases. When it rises to be close to the oil pressure of the system load-sensitive oil circuit and finally balances, the opening of the LS valve core (5) will eventually form a balance point that produces appropriate pressure loss according to the load pressure of the execution unit and the pressure difference of the LS transition chamber 131, so that the execution unit with lower pressure can maintain a reasonable flow rate.

[0032] When the main valve core (2) is in the neutral position, the oil inlet chamber (110) and the first transition chamber (111) are blocked by the first shoulder (21), and the first back pressure chamber (112) and the second back pressure chamber (119) are connected and in the state of maximum opening. When the main valve core (2) gradually moves to both sides, the opening between the first back pressure chamber (112) and the second back pressure chamber (119) gradually decreases, and the pressure gradually increases. As the pressure in the chamber close to the system pressure oil circuit gradually increases, the pressure in the oil inlet chamber (110), which is also connected to the system pressure oil circuit, also increases synchronously, thus establishing back pressure in advance for the start-up of the actuator.

[0033] Through the above structure, a structure is formed as follows: Figure 6 The functions shown are as follows.

[0034] like Figure 6 , 7 As shown, the open center multi-way valve includes several reversing valves, a first relief valve (6), a second relief valve (7), and an LS constant flow valve (8). The reversing coupling includes a main valve core (2), whose valve body is provided with a P port for external connection to the inlet oil pipeline, a T port for external connection to the return oil pipeline, and working oil ports A and B. The main valve core (2) is proportionally controlled and is provided with left, middle and right positions. There are transition ports P1 and P2 between the P port and the A / B port. There is an LS valve core between the P1 and P2 ports. The LS valve core is provided with left, middle and right positions. The pilot oil circuits on both sides of the LS valve core are respectively connected to the P1 port and the system LS oil circuit. The proportional control of its displacement is achieved by the pressure of the P1 port and the system LS oil circuit. The oil inlet end of the LS valve core is connected to the P1 port, and the two oil outlets are respectively connected to the system LS oil circuit and the P2 port. The oil outlet and the oil inlet connected to the system LS oil circuit are connected through the oil passage inside the valve core. The opening between the oil outlet and the oil inlet connected to the P2 port is controlled by the displacement of the LS valve core. Both ends of the main valve core (2) are equipped with hydraulic pilot oil circuits a1, b1, a2, b2, a3, and b3 to control the valve core reversal. Back pressure passages P3 and P4 are also provided at the main valve core, with the opening of the ports from P3 to P4 controlled by the displacement of the main valve core (2). A one-way valve is installed between the LS valve core outlet and port P2, allowing unidirectional flow from the LS valve core outlet to port P2. Each of the working ports A1, B1, A2, B2, A3, and B3 is equipped with a relief valve.

[0035] The first relief valve (6) is a differential relief valve. Its inlet is connected to the system pressure oil circuit, its two pilot ports are connected to the system pressure oil circuit and the LS oil circuit respectively, and its outlet is connected to the return oil line. The second relief valve (7) and the LS constant flow valve (8) are set in parallel. The inlet of the second relief valve (7) and one side port of the LS constant flow valve (8) are connected to the LS oil circuit. The outlet of the second relief valve (7) and the other side port of the LS constant flow valve (8) are connected to a separate S oil circuit return oil tank to avoid interference from the return oil of other components.

[0036] like Figure 8 , 9 As shown, in addition to the above embodiments, the main valve core function of the multi-way valve reversing linkage of the present invention can also be various mid-position functions included in Q-type, Y-type, P-type and other reversing valves, in order to adapt to different working conditions.

[0037] In the above embodiment, the pressure source is a metering pump on the P01 side. Furthermore, it can also be such as... Figure 10 In the multi-way valve, there are dual pressure sources on both sides of P01 and P02. Both P01 and P02 are driven by a motor-driven fixed displacement pump. When the multi-way valve is operating, both pressure sources supply oil simultaneously, making flow control more flexible. Correspondingly, the P02 port is located in the tail connection of the multi-way valve. Figure 11 As shown. Furthermore, a one-way valve is installed at the connection point between P01 and P02, extending from P01 to P02, as shown. Figure 12 As shown, this avoids adverse effects between pressure sources.

Claims

1. A center-operated multi-way valve reversing coupling, comprising a main valve core (2), wherein the valve body is provided with a P port for external connection to the inlet oil pipeline, a T port for external connection to the return oil pipeline, and working oil ports A and B, characterized in that: The main valve core (2) is proportionally controlled and has left, middle and right positions; there are transition ports P1 and P2 between port P and port A / B, and an LS valve core (5) is set between ports P1 and P2. The LS valve core (5) has left, middle and right positions. The pilot oil circuits on both sides of the LS valve core are connected to port P1 and the system LS oil circuit respectively. The proportional control of its displacement is achieved by the pressure of port P1 and the system LS oil circuit. The oil inlet of the LS valve core (5) is connected to port P1, and the two oil outlets are connected to the system LS oil circuit and port P2 respectively. The oil outlet and oil inlet of the system LS oil circuit are connected through the oil passage inside the valve core. The opening between the oil outlet and oil inlet of the P2 port is controlled by the displacement of the LS valve core. The main valve core (2) has hydraulic pilot oil circuits a1 and b1 at both ends to control the valve core reversal.

2. The open-center multi-way valve reversing coupling according to claim 1, characterized in that: Back pressure passages P3 and P4 are also provided at the main valve core (2), and the opening of the oil port from P3 to P4 is controlled by the displacement of the main valve core (2).

3. The open-center multi-way valve reversing coupling according to claim 1, characterized in that: A one-way valve is provided between the oil outlet of the LS valve core (5) and the P2 port, allowing one-way flow from the oil outlet of the LS valve core (5) to the P2 port.

4. A center-opening multi-way valve, characterized in that: It includes several open-center multi-way valves with reversing connections and a first relief valve (6) connected in parallel. The first relief valve (6) is an equal-differential relief valve, whose inlet is connected to the system pressure oil circuit, its two pilot ports are connected to the system pressure oil circuit and the LS oil circuit respectively, and its outlet is used for oil discharge.

5. The open-center multi-way valve according to claim 4, characterized in that: It also includes an LS constant flow valve (8), with one side of the LS constant flow valve (8) connected to the LS oil circuit and the other side used for oil draining.

6. The open-center multi-way valve according to claim 5, characterized in that: It also includes a second overflow valve (7), the oil inlet of which is connected to the LS oil circuit and the oil outlet is used for oil discharge.

7. The open-center multi-way valve according to claim 4, characterized in that: The pilot oil sources on both sides of the main valve core (2) are connected through an electro-proportional pressure reducing valve or a high-speed switching valve.

8. A valve body for implementing the open-center multi-way valve reversing function as described in any one of claims 1-3, comprising a valve body (1), a first valve hole (11) provided in the valve body (1), a main valve core (2) installed in the first valve hole (11), an oil inlet chamber (110) provided in the middle of the first valve hole (11), a first working oil port transition chamber (115) and a second working oil port transition chamber (116) respectively provided on both sides of the oil inlet chamber (110), the first working oil port transition chamber (115) connecting to the first working oil port (31), the second working oil port transition chamber (116) connecting to the second working oil port (32), and a first return oil transition chamber provided outside the first working oil port transition chamber (115). (117), a second return oil transition chamber (118) is provided outside the second working oil port transition chamber (116). The first return oil transition chamber (117) and the second return oil transition chamber (118) are connected to the return oil chamber (33). The main valve core (2) is provided with a shoulder. The sliding of the main valve core (2) allows the first working oil port transition chamber (115) and the second working oil port transition chamber (116) to be connected to or blocked from the oil chambers on both sides. The valve body (1) is also provided with an oil inlet passage (41) and an oil return passage (42). The oil inlet passage (41) and the oil return passage (42) are perpendicular to the first valve hole. The oil inlet passage (41) is connected to the oil inlet chamber (110), and the oil return passage (42) is connected to the oil return chamber (33). Its characteristics are: The valve body (1) is also provided with a second through hole (12) and a third valve hole (13). The second through hole (12) is parallel to the first valve hole (11), and the third valve hole (13) is perpendicular to the second through hole (12). A first transition chamber (111) is provided on one side of the oil inlet chamber (110), and the first transition chamber (111) is connected to the bottom of the third valve hole (13). The valve body (1) is also provided with an LS oil passage (43) parallel to the oil inlet passage (41) and the oil return passage (42). The LS oil passage (43) penetrates the valve body (1) and intersects with the third valve hole (13). An LS valve core (5) is provided in the third valve hole (13). The LS valve core (5) is located in the third valve hole (13). 13) Sliding inside, controlling the opening between the bottom of the third valve hole (13) and the second through hole. An inner oil passage (50) is provided inside the LS valve core (5). The openings on both sides of the inner oil passage (50) are located on the bottom and top of the LS valve core (5), respectively. The position of the top opening matches the position of the LS oil passage (43). A third transition chamber (113) is provided between the first transition chamber (111) and the first working oil port transition chamber (115). A fourth transition chamber (114) is provided between the oil inlet chamber (110) and the second working oil port transition chamber (116). The third transition chamber (113) and the fourth transition chamber (114) are respectively connected to the second through hole (12). The main valve core (2) is provided with a first shoulder (2). 1) Second shoulder (22), third shoulder (23), fourth shoulder (24), and fifth shoulder (25). The first shoulder (21) is located in the middle of the main valve core and is set between the oil inlet chamber (110) and the first transition chamber (111). The first shoulder (21) has a first throttling groove (211) and a second throttling groove (212) on both sides, thereby controlling the opening of the oil inlet chamber (110) to the first transition chamber (111). The second shoulder (22) and the third shoulder (23) are located on both sides of the first shoulder (21). The second shoulder (22) is set between the first transition chamber (111), the third transition chamber (113), and the first working oil port transition chamber (115), controlling the opening of the third transition chamber (111). 3) The opening and closing of the first working oil port transition chamber (115) simultaneously prevents the first transition chamber (111) and the third transition chamber (113) from communicating; the third shoulder (23) is located in the fourth transition chamber (114) and the second working oil port transition chamber (116) to control the opening and closing of the fourth transition chamber (114) and the second working oil port transition chamber (116); the fourth shoulder (24) is located outside the second shoulder (22), and the fourth shoulder (24) is located in the first return oil transition chamber (117) to control the opening and closing of the first return oil transition chamber (117); the fifth shoulder (25) is located outside the third shoulder (23), and the fifth shoulder (25) is located in the second return oil transition chamber (118) to control the opening and closing of the second return oil transition chamber (118).

9. The open-center multi-way valve reversing valve body according to claim 8, characterized in that: A first back pressure chamber (112) and a second back pressure chamber (119) are provided between the oil inlet chamber (110) and the fourth transition chamber (114). The first back pressure chamber (112) and the second back pressure chamber (119) are respectively connected to the system pressure oil circuit and the return oil circuit. A sixth shoulder (26) is provided between the third shoulder (23) and the first shoulder (21) in the main valve core (2). The sixth shoulder (26) is located between the second back pressure chamber (119) and the first back pressure chamber (112). The right side of the third shoulder (23) and the left side of the sixth shoulder (26) control the connection and disconnection between the second back pressure chamber (119) and the first back pressure chamber (112). The sixth shoulder (26) also ensures that the oil inlet chamber (110) and the first back pressure chamber (112) are not connected.

10. The open-center multi-way valve reversing valve body according to claim 8, characterized in that: The second through hole (12) is located on both sides of the third valve hole (13) and the first one-way valve core (51) and the second one-way valve core (52) are respectively installed, so that the oil in the second through hole (12) located on both sides of the third valve hole (13) can be unidirectionally guided to the third transition chamber (113) and the fourth transition chamber (114).

11. The open-center multi-way valve reversing valve body according to claim 8, 9 or 10, characterized in that: The second through hole (12) is located outside the first one-way valve core (51) and the second one-way valve core (52), respectively provided with a third overflow valve core (53) and a fourth overflow valve core (54). The inlets of the third overflow valve core (53) and the fourth overflow valve core (54) are respectively connected to the oil circuit of the first working oil port transition chamber (115) and the second working oil port transition chamber (116). The outlets of the third overflow valve core (53) and the fourth overflow valve core (54) are respectively connected to the first return oil transition chamber (117) and the second return oil transition chamber (118).

12. A valve body for implementing the open-center multi-way valve function as described in any one of claims 4-7, comprising a plurality of open-center multi-way valve directional valve bodies as described in any one of claims 8-11, characterized in that: Several open-center multi-way valve reversing valve bodies are respectively equipped with a first valve body and a tail valve body on both sides. The first valve body is connected to the hydraulic pump outlet and is provided with an oil port that connects to the oil inlet channel and LS oil circuit of the open-center multi-way valve reversing valve body. The tail valve body is connected to the oil tank and is provided with an oil port that connects to the oil return channel of the open-center multi-way valve reversing valve body. The first or tail valve body is provided with an equal-gradient overflow valve hole.

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