Integrated load-sensitive proportional multi-way valve and control method

Abstract

The invention discloses an integrated load-sensitive proportional multi-way valve and a control method. Comprising a reversing block valve body which is provided with a main oil way channel, an LS load feedback oil way and a pilot control oil way; an oil path P, an oil port A, an oil port B and an oil path R which are communicated with the main oil path channel are arranged on the main oil path channel; the main valve element is arranged in a valve hole of the main valve element of the reversing block valve body in a sliding mode and used for switching connection and disconnection among the oil way P, the oil port A, the oil port B and the oil way R; a pressure compensator is controlled to be connected and disconnected with the P oil way or the LS load feedback oil way; the LS load feedback pressure is controlled to the shuttle valve and the LS load feedback pressure neutral position for unloading; in some systems, some actions need stable flow output, and some actions are easy to generate system oscillation, so that pressure control is selected, and the pressure control and the flow control are further respectively realized at an oil port A and an oil port B of the same reversing block.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and particularly relates to an integrated load-sensing proportional multi-way valve and a control method thereof. Background Art

[0002] When the flow control type commutation block is working, especially in a system with a high-inertia load, in order to ensure a constant pressure difference before and after the main spool, the system pressure Pc will change with the frequency of the high-inertia load pressure Pl, and finally maintain a stable flow output of the valve. For all Ls systems, the oscillation frequency is between 1 / 2 - 2 Hz. For some typical applications, such as large inertia loads or working conditions with pressure control valves, such as the oscillation of the system when used with a balance valve. When the balance valve opens through the pilot pressure and the hydraulic oil at port B of the system returns to the fuel tank, the pressure at port A will decrease, and at this time, there is a situation where the balance valve closes. In these working conditions, continuous oscillation of the system will occur.

[0003] In the prior art, the flow control type commutation block realizes flow stability by dynamically adjusting ΔP. However, in essence, it relies on the instantaneous pressure difference feedback between Pl and Pc, resulting in a coupled oscillation between the system pressure and the load pressure. Although some improvement schemes attempt to introduce damping or compensation circuits, it is still difficult to effectively suppress oscillation under high-inertia or transient impact working conditions, and it may introduce additional energy consumption or control complexity. Therefore, there is an urgent need for a new type of pressure control strategy to solve the oscillation problem of the Ls system and improve the robustness and adaptability of the hydraulic system. Summary of the Invention

[0004] The present invention aims at the above problems and provides an integrated load-sensing proportional multi-way valve and a control method thereof, which has a delicate structure, solves the oscillation problem of the Ls system, and improves the adaptability of the hydraulic system.

[0005] The technical solution of the present invention is as follows: An integrated load-sensing proportional multi-way valve and a control method thereof, comprising: A commutation block valve body, provided with a main oil passage, an LS load feedback oil passage, and a pilot control oil passage; a P oil passage, an A oil port, a B oil port, and an R oil passage communicating with the main oil passage are provided on the main oil passage; A main spool, slidably arranged in the main spool valve hole of the commutation block valve body, used for switching the on-off between the P oil passage, the A oil port, the B oil port, and the R oil passage; controlling the on-off of the pressure compensator with the P oil passage or the LS load feedback oil passage; controlling the LS load feedback pressure to the shuttle valve and the LS load feedback pressure to unload in the middle position; A pressure compensator, arranged in the pressure compensator valve hole between the P oil passage and the main spool; A pressure control valve assembly, comprising a pressure control valve sleeve, a pressure control valve core, a pressure control valve seat and a pressure control valve body; the pressure control valve body is fixedly arranged on one side of the main valve core valve hole; the pressure control valve sleeve and the pressure control valve seat are fixedly arranged in the pressure control valve body; the pressure control valve core is slidably arranged between the pressure control valve sleeve and the pressure control valve seat; A spring cover is fixedly arranged on the other side of the main valve core valve hole; a left retaining ring, a right retaining ring, a reset inner spring and an electro-controlled outer spring are arranged in the spring cover; the right retaining ring is fixedly connected with the main valve core; the left retaining ring is movably sleeved on the extension rod of the main valve core; the reset inner spring is arranged between the left retaining ring and the right retaining ring and is used for resetting the main valve core when the operation at the A oil port ends; the electro-controlled outer spring is arranged between the left retaining ring and the spring cover and is used for comparing the main valve core with the electro-controlled pilot control pressure in the right cavity of the pressure control valve body when the operation at the B oil port is carried out; A proportional relief valve, comprising a proportional relief valve one and a proportional relief valve two, which are respectively fixedly arranged in the proportional relief valve holes of the pilot control oil circuit and are driven by corresponding electromagnets; A shuttle valve is arranged in the shuttle valve hole of the LS load feedback oil circuit of the commutation block.

[0006] Specifically, the outer end of the pressure control valve sleeve is fixedly and sealingly connected with the pressure control valve body; The pressure control valve seat is fixedly and sealingly connected with the inner end of the pressure control valve sleeve; [[ID=1३]]A pressure control sliding cavity adapted to the pressure control valve core is formed between the pressure control valve sleeve and the pressure control valve seat.

[0007] Specifically, the cross section of the pressure control valve core is in a T-shaped structure, one end is located in the pressure control sliding cavity, and the other end extends out from the through hole in the middle of the pressure control valve seat 403 and is used for propping up the main valve core.

[0008] Specifically, the pressure compensator comprises a compensating valve core, the first end of which is in pressure communication with the P oil circuit, and the second end of which is in communication with the load pressure cavity through a compensating spring.

[0009] Specifically, the following are arranged in the spring cover: A reset inner spring with a stiffness coefficient of 0.5 - 1.2 N / mm, configured to provide the reset force of the main valve core in the pressure control mode; An electro-controlled outer spring with a stiffness coefficient of 30 - 35 N / mm, configured to form a displacement-force balance relationship with the pilot pressure in the flow control mode.

[0010] Specifically, the pressure control valve assembly and the proportional pressure reducing valve cooperate. In the pressure control mode, the pressure at port A pushes the main spool in the opposite direction through the pressure control spool, achieving a force closed-loop control with the pilot pressure. In the flow control mode, the displacement of the main spool is determined by the combined force of the pilot pressure and the electric control external spring, and the pressure compensator maintains a constant ΔP.

[0011] A control method for an integrated load-sensing proportional multi-way valve, comprising: In the neutral state, the pilot control oil in the spring cover and the pressure control valve body is respectively connected to the T oil circuit, and the LS load feedback pressure is connected to the R oil circuit through the main spool, realizing the unloading of the LS load feedback oil circuit. At this time, ports A, B, the P oil circuit, and the R oil circuit are all blocked. In the pressure control mode, the pressure at port A is directly compared with the pilot pressure output by the proportional pressure reducing valve through the pressure control valve assembly. In the flow control mode, the pressure compensator dynamically adjusts ΔP at both ends of the main spool, making the flow rate determined only by the displacement of the main spool.

[0012] Specifically, in the pressure control state; The solenoid coil A is energized, and the push rod of the solenoid coil A pushes the first spool of the proportional pressure reducing valve to move to the left, so that the pilot control oil circuit outputs pressure to the spring cover, and the magnitude of the output pressure is proportional to the magnitude of the energizing current of the solenoid coil A. Under the control of the pilot control oil pressure, the main spool moves to the left, connecting the P oil circuit to port A and the R oil circuit to port B. The pressure at port A is fed back to the shuttle valve through the main spool for comparison with the load pressure of other commutation joints. The shuttle valve feeds back the higher load pressure to the variable pump to achieve the load-sensing control function. At the same time, the pressure at port A is fed back to the pressure control valve assembly, causing the pressure control spool to move to the right and contact the main spool. The left side of the main spool is subjected to the thrust of the pressure control spool, and the right side is subjected to the pilot control oil pressure; Thrust of the left pressure control spool = Pressure at port A * Passage area of the pressure control spool; Force on the right side of the main spool = Pilot control oil pressure * Passage area of the main spool and spring force of the return inner spring; When comparing the forces on the left and right sides of the main spool: When the left force is larger, the pressure control spool pushes the main spool to move to the right, cutting off the connection between the P oil circuit and port A.

[0013] When the right-side force is relatively large, the pilot control oil pressure pushes the main spool to move leftward, increasing the flow area between the P oil passage and the A oil passage, achieving dynamic balance of the two-side forces. Thus, by controlling the magnitude of the energizing current of the solenoid coil A, the magnitude of the pilot control oil pressure is changed, and further the magnitude of the output pressure at the A oil port is controlled. At this time, the P oil passage is connected to the control chamber of the pressure compensator through the main spool, and the pressures on both sides of the pressure compensator are both the pressure of the P oil passage. Under the action of the spring force, the pressure compensator is in a normally open state.

[0014] Specifically, in the flow control state; The solenoid coil B is energized, and the push rod of the solenoid coil B pushes the spool of the proportional pressure reducing valve II to move leftward, causing the output pressure of the pilot control oil passage to enter the right chamber of the pressure control valve body. The magnitude of the output pressure is proportional to the magnitude of the energizing current of the solenoid coil B. Under the control of the pilot control oil pressure, the main spool moves rightward. The P oil passage is connected to the B oil port, and the R oil passage is connected to the A oil port. The pressure at the B oil port is fed back to the shuttle valve through the main spool and compared with the magnitude of the load pressure of other commutation links. The shuttle valve feeds back the higher load pressure to the variable pump to achieve the load sensing control function. At the same time, it is fed back to the pressure control valve assembly, causing the pressure control spool to move rightward. At this time, the main spool also moves rightward, so the pressure control spool and the main spool do not contact.

[0015] Specifically, the left side of the main spool is subject to the pilot control oil pressure, and the right side is subject to the spring forces of the electric control external spring and the reset internal spring. The force on the left side of the main spool = pilot control oil pressure * cross-sectional area of the main spool's through-hole. When comparing the forces on the left and right sides of the main spool, the moving position of the main spool is determined by the pilot control oil pressure, and the pilot control oil pressure is determined by the magnitude of the current of the solenoid coil B. The LS load feedback oil passage connects the pressure at the B oil port to the control chamber of the pressure compensator through the main spool. The pressure on the right side of the pressure compensator is the pressure of the P oil passage, and the pressure on the left side is the pressure at the B oil port and the spring force of the pressure compensator. By comparing the pressures on the left and right sides, the connection and closing of the pressure compensator spool are controlled, so as to control the pressure difference on both sides of the main spool opening to always be maintained at 6 - 7 bar, thereby realizing that the output flow rate of the main spool is only related to the opening size of the main spool.

[0016] Advantages of the present invention: Aiming at the oscillation problem of the system, a pressure control type commutation block is designed. When the control current is constant, Pc is a constant pressure, and Pl is the fluctuating load pressure. However, the pressure difference between Pc and Pl will become smaller and smaller over time, resulting in the change of the system flow rate Ql. The resistance to pressure fluctuation comes from the fluctuation of the flow rate, that is, the change of the pressure difference. Thus, the elimination effect on pressure oscillation is achieved.

[0017] In some systems, certain actions require a stable flow output, while certain actions are prone to system oscillations, so pressure control is selected. Further, pressure control and flow control are respectively implemented at the A and B ports of the same switching block. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a three-dimensional structural schematic diagram of the split state of the present invention; Figure 2 is a cross-sectional structural schematic diagram of the present invention; Figure 3 is a structural schematic diagram of the pressure compensator; Figure 4 is a structural schematic diagram of the flow control state; Figure 5 is a structural schematic diagram of the pressure control state; Figure 6 is a structural schematic diagram of the neutral state; Figure 7 is a structural schematic diagram of the main spool valve; Figure 8 is a structural schematic diagram of the interior of the spring cover; Figure 9 is a structural schematic diagram of the principle of the present invention; In the figure, 1 is the switching block valve body, 2 is the main spool valve, 3 is the pressure compensator, 301 is the compensating spool valve, 302 is the compensating spring, 303 is the load pressure chamber, 4 is the pressure control valve assembly, 401 is the pressure control valve sleeve, 402 is the pressure control spool valve, 403 is the pressure control valve seat, 404 is the pressure control valve body, 5 is the spring cover, 51 is the left retaining ring, 52 is the right retaining ring, 53 is the reset inner spring, 54 is the electrically controlled outer spring, 6 is the proportional pressure reducing valve, 7 is the electromagnet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention. In the description of the present invention, unless otherwise specified, the meaning of "plural" is two or more.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly defined 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 circumstances.

[0022] An integrated load-sensing proportional multi-way valve, comprising: A directional valve body 1, provided with a main oil passage, an LS load feedback oil passage ( Figure 4 the part shown by the purple dotted line in the figure) and a pilot control oil passage ( Figure 4 the part shown by the yellow dotted line in the figure); a P oil passage, an A oil port, a B oil port and an R oil passage communicating with the main oil passage are provided on the main oil passage; A main spool 2, slidably arranged in the main spool valve hole of the directional valve body 1, for switching the on-off between the P oil passage, the A oil port, the B oil port and the R oil passage; at the same time, the main spool 2 controls the on-off between the P oil passage ( Figure 4 the part shown by the red dotted line in the figure) or the LS load feedback oil passage and the control chamber of the pressure compensator 3; at the same time, the main spool 2 controls the LS load feedback pressure to the shuttle valve and the LS load feedback pressure neutral unloading; Specifically, as Figure 6 shown, when configured in the first position (neutral position), the connection between the P oil passage and the A / B oil ports is cut off; As Figure 4 shown, in the second position (a position), the P oil passage → A oil port is connected, the B oil port → R oil passage is connected, and the P oil passage is connected to the control chamber of the pressure compensator 3; As Figure 5 shown, in the third position (b position), the P oil passage → B oil port is connected, the A oil port → R oil passage is connected, and the LS load feedback oil passage is connected to the control chamber of the pressure compensator 3; In this case, the on / off between the P oil passage, A oil port, B oil port and R oil passage is achieved by two spaced flow grooves 21 on the main spool 2; the on / off between the control chambers of the pressure compensator 3 and the P oil passage or the LS load feedback oil passage is achieved by multiple groups of counterbores 22. The number of each group of counterbores is set to ensure that during the full stroke of the main spool commutation, the control chambers of the pressure compensator 3 are always connected to the P oil passage or the LS load feedback oil passage respectively.

[0023] The pressure compensator 3 is arranged in the pressure compensator valve hole between the P oil passage and the main spool 2, and maintains the pressure difference ΔP between the two ends of the main spool 2 constant at 6 - 7 bar in the flow control mode; ΔP is the pressure difference between the two ends of the main spool 21 passage. The pressure control valve assembly 4 includes a pressure control valve sleeve 401, a pressure control spool 402, a pressure control valve seat 403 and a pressure control valve body 404; the pressure control valve body 404 is fixedly arranged on one side of the main spool valve hole; the pressure control valve sleeve 401 and the pressure control valve seat 403 are fixedly arranged in the pressure control valve body 404; the pressure control spool 402 is slidably arranged between the pressure control valve sleeve 401 and the pressure control valve seat 403. As Figure 5 shown, when the A oil port is connected to the P oil passage and the B oil port is connected to the R oil passage, the control chamber of the pressure control spool 402 is connected to the A oil port. When the pressure control spool 402 pushes the main spool 2 towards the spring cover direction, one side of the main spool 2 close to the spring cover 5 is subject to the pilot control pressure, one side is the thrust of the pressure control spool push rod, the magnitude of the thrust is determined by the pressure of the A oil port, and the other side is the pressure of the pilot control oil. These two forces are compared for dynamic force balance. The spring cover 5 is fixedly arranged on the other side of the main spool valve hole; the spring cover 5 is provided with a left retaining ring 51, a right retaining ring 52, a reset inner spring 53 and an electric control outer spring 54; the right retaining ring is fixedly connected to the main spool 2; the left retaining ring is movably sleeved on the extension rod of the main spool 2, the diameter of the extension rod is smaller than the diameter of the main spool 2, and a step is formed between them; the reset inner spring is arranged between the left retaining ring and the right retaining ring for the main spool to reset when the work of the A oil port ends; the electric control outer spring is arranged between the left retaining ring and the spring cover 5 for the main spool to compare with the electric control pilot control pressure in the right chamber of the pressure control valve body when the B oil port is working. The proportional pressure reducing valve 6 includes a proportional pressure reducing valve one and a proportional pressure reducing valve two, which are respectively fixedly arranged in the proportional pressure reducing valve holes of the pilot control oil passage and are driven by the corresponding electromagnets 7; the system pilot pressure source (2 MPa) is adjusted to a variable pilot pressure output according to the input current and output to the spring cover 5 or the cavity of the pressure control valve body 404. The shuttle valve 8 is arranged in the shuttle valve hole of the LS load feedback oil circuit of the reversing block, and is used to compare the load pressure of the pressure / flow control reversing joint with the load pressure of the flow / flow control reversing joint of the valve group, and then feedback the higher load pressure to the variable pump. The pressure control valve assembly 4 and the proportional pressure reducing valve 6 cooperate with each other. In the pressure control mode, the pressure at port A pushes the main spool 2 back through the pressure control spool 402, and a force closed-loop control is achieved with the pilot pressure; in the flow control mode, the displacement of the main spool 2 is determined by the resultant force of the pilot pressure and the electric control external spring 8, and the ΔP is maintained constant by the pressure compensator 3.

[0024] The structure of the pressure control valve assembly 4 is further described as follows: The outer end of the pressure control valve sleeve 401 is fixedly and sealingly connected to the pressure control valve body 404; The pressure control valve seat 403 is fixedly and sealingly connected to the inner end of the pressure control valve sleeve 401; A pressure control sliding cavity adapted to the pressure control spool 402 is formed between the pressure control valve sleeve 401 and the pressure control valve seat 403.

[0025] The cross-section of the pressure control spool 402 is in a T-shaped structure. One end is located in the pressure control sliding cavity, and the other end extends out from the through hole in the middle of the pressure control valve seat 403 for propping up the main spool 2.

[0026] The structure of the pressure compensator 3 is further described as follows: The pressure compensator 3 includes a compensating spool 301. Its first end is in pressure communication with the P oil circuit, and its second end is in communication with the load pressure chamber 303 through a compensating spring 302; The load pressure chamber 303 receives the load pressure of the multi-way valve through the LS load feedback oil circuit, and forms a differential pressure feedback loop with the pressure on the outlet side of the main spool 2, or receives the P oil circuit pressure, and the compensating spool 301 is in a normally open state under the action of the spring force of the compensating spring 302.

[0027] Inside the spring cover 5 of this case: The reset inner spring 53 has a stiffness coefficient of 0.5 - 1.2 N / mm and is configured to provide a reset force for the main spool 2 in the pressure control mode; The electric control external spring 54 has a stiffness coefficient of 30 - 35 N / mm and is configured to form a displacement-force balance relationship with the pilot pressure in the flow control mode.

[0028] An integrated load sensing proportional multi-way valve and control method, including: In the neutral state, as Figure 7As shown; the pilot control oil in the spring cover 5 and the pressure control valve body 404 is respectively connected to the T oil circuit, and the LS load feedback pressure is connected to the R oil circuit through the main spool 2, realizing the unloading of the LS load feedback oil circuit. At this time, the A oil port, B oil port, P oil circuit, and R oil circuit are all blocked; In the pressure control mode, the pressure at the A port is directly compared with the pilot pressure output by the proportional pressure reducing valve 6 through the pressure control valve assembly 4; In the flow control mode, the ΔP at both ends of the main spool 2 is dynamically adjusted by the pressure compensator 3, so that the flow rate is only determined by the displacement of the main spool; When in the pressure control state, as Figure 6 shown; When the coil A of the electromagnet 7 is energized, the push rod of the coil A of the electromagnet 7 pushes the spool of the proportional pressure reducing valve 1 to move to the left, so that the pilot control oil circuit outputs pressure to the spring cover 5, and the magnitude of the output pressure is proportional to the magnitude of the energizing current of the coil A of the electromagnet 7; Under the control of the pilot control oil pressure, the main spool 2 moves to the left, connecting the P oil circuit with the A oil port and the R oil circuit with the B oil port; the pressure at the A oil port is fed back to the shuttle valve 8 through the main spool 2 for comparison with the magnitude of the load pressure of other loads. The shuttle valve feeds back the higher load pressure to the variable pump to realize the load sensing control function. At the same time, the pressure at the A oil port is fed back to the pressure control valve assembly 4, causing the pressure control spool 402 to move to the right and contact the main spool 2. The left side of the main spool 2 is subjected to the thrust of the pressure control spool 402, and the right side is subjected to the pilot control oil pressure; Thrust of the left pressure control spool = Pressure at the A oil port * Passing area of the pressure control spool; Force on the right main spool = Pilot control oil pressure * Passing area of the main spool and spring force of the return inner spring (the spring force of the return inner spring is relatively small and can be ignored). In this case, the passing diameter of the main spool is 20 mm, the passing diameter of the pressure control spool is 4.5 mm, and the pilot control pressure change range is 0 - 1.8 MPa. From this, the control pressure range of the A oil port can be calculated as 0 - 35.5 MPa.

[0029] When comparing the forces on both sides of the main spool 2: When the left force is larger, the pressure control spool 402 pushes the main spool to move to the right, cutting off the connection between the P oil circuit and the A oil port.

[0030] That is: in the pressure control mode, when the force F1 exerted by the pressure at the A oil port on the pressure control spool 402 and the force F2 exerted by the pilot pressure on the right side of the main spool satisfy F1 ≥ F2, the main spool 2 closes the P→A channel; When F1 < F2, the main spool 2 opens the P→A channel, and the opening degree is dynamically adjusted by the difference value of (F2 - F1).

[0031] When the right-side force is relatively large, the pilot control oil pressure pushes the main spool 2 to move leftward, increasing the flow area between the P oil passage and the A oil passage, achieving dynamic balance of the forces on both sides. Thus, by controlling the magnitude of the energizing current of coil A of the electromagnet 7, the magnitude of the pilot control oil pressure is changed, and further the magnitude of the output pressure of the A oil port is controlled. At this time, the P oil passage is connected to the control chamber of the pressure compensator 3 through the main spool 2, and the pressures on both sides of the pressure compensator 3 are both the pressure of the P oil passage. Under the action of the spring force, the pressure compensator 3 is in a normally open state.

[0032] In the flow control state, as Figure 5 shown; Coil B of the electromagnet 7 is energized, and the push rod of coil B of the electromagnet 7 pushes the spool of the proportional pressure reducing valve II to move leftward, causing the output pressure of the pilot control oil passage to enter the right chamber of the pressure control valve body. The magnitude of the output pressure is proportional to the magnitude of the energizing current of coil B of the electromagnet 7. Under the control of the pilot control oil pressure, the main spool 2 moves rightward, the P oil passage is connected to the B oil port, and the R oil passage is connected to the A oil port. The pressure of the B oil port is fed back to the shuttle valve 8 through the main spool 2, and compared with the magnitude of the load pressure of other commutation joints. The shuttle valve feeds back the higher load pressure to the variable pump to achieve the load sensing control function, and at the same time feeds back to the pressure control valve assembly 4, causing the pressure control spool 402 to move rightward. At this time, the main spool also moves to the right, so the pressure control spool 402 does not contact the main spool 2.

[0033] The left side of the main spool 2 is subject to the pilot control oil pressure, and the right side is subject to the spring forces of the electric control external spring 54 and the return internal spring 53 (the spring force of the return internal spring is relatively small and can be ignored). The force on the left side of the main spool = pilot control oil pressure * cross-sectional area of the main spool's through-hole diameter. In this case, the through-hole diameter of the main spool is 20 mm, and the variation range of the pilot control pressure is 0 - 1.8 MPa; the variation range of the spring force of the electric control external spring is 110 - 370 N.

[0034] When comparing the forces on the left and right sides of the main spool 2, the main spool 2 moves to a certain specific position, which is determined by the pilot control oil pressure, and the pilot control oil pressure is determined by the magnitude of the current of coil B of the electromagnet line 7. The LS load feedback oil passage connects the pressure of the B oil port to the control chamber of the pressure compensator 3 through the left-side counterbore of the main spool 2. The pressure on the right side of the pressure compensator 3 is the pressure of the P oil passage, and the pressure on the left side is the pressure of the B oil port and the spring force of the pressure compensator 3. By comparing the pressures on the left and right sides, the connection and closing of the spool of the pressure compensator 3 are controlled, so as to control the pressure difference on both sides of the opening of the main spool 2 to always be maintained at 6 - 7 bar, thereby realizing that the output flow rate of the main spool 2 is only related to the opening size of the main spool 2, that is, related to the stroke of the main spool 2, and this stroke is determined by the magnitude of the energizing current of the electromagnetic coil B.

[0035] Regarding the content disclosed in this case, the following points also need to be explained: (1) The accompanying drawings of the embodiments disclosed in this case only relate to the structures involved in the embodiments disclosed in this case. For other structures, reference may be made to the general design; (2) Without conflict, the embodiments disclosed in this case and the features in the embodiments may be combined with each other to obtain new embodiments; The above is only the specific implementation manner disclosed in this case, but the protection scope of this disclosure is not limited thereto. The protection scope disclosed in this case shall be subject to the protection scope of the claims.

Claims

1. An integrated load sensing proportional multi-way valve, characterized in that, Comprising: A reversing block valve body (1), provided with a main oil passage, an LS load feedback oil passage, and a pilot control oil passage; A main spool (2), slidably arranged in the main spool valve hole of the reversing block valve body (1), switching the on-off between the P oil passage, the A oil port, the B oil port, and the R oil passage on the main oil passage; controlling the on-off of the control pressure compensator (3) with the P oil passage or the LS load feedback oil passage respectively; controlling the LS load feedback pressure to the shuttle valve and the LS load feedback pressure neutral unloading; A pressure compensator (3), arranged in the pressure compensator valve hole between the P oil passage and the main spool (2); A pressure control valve assembly (4), including a pressure control valve sleeve (401), a pressure control spool (402), a pressure control valve seat (403), and a pressure control valve body (404); the pressure control valve body (404) is fixedly arranged on one side of the main spool valve hole of the main spool (2); the pressure control valve sleeve (401) and the pressure control valve seat (403) are fixedly arranged in the pressure control valve body (404); the pressure control spool (402) is slidably arranged between the pressure control valve sleeve (401) and the pressure control valve seat (403); A spring cover (5), fixedly arranged on the other side of the main spool valve hole; internally provided with a left retaining ring (51), a right retaining ring (52), a reset inner spring (53), and an electrically controlled outer spring (54); the right retaining ring (52) is fixedly connected to the main spool (2); the left retaining ring is movably sleeved on the extension rod of the main spool (2); the reset inner spring is arranged between the left retaining ring and the right retaining ring, used for resetting the main spool when the work of the A oil port ends; the electrically controlled outer spring is arranged between the left retaining ring and the spring cover (5), used for comparing the main spool with the electrically controlled pilot control pressure in the right cavity of the pressure control valve body when the B oil port is working; A proportional reducing valve (6), including a first proportional reducing valve and a second proportional reducing valve, respectively fixedly arranged in the proportional reducing valve holes of the pilot control oil passage, and driven by corresponding electromagnets (7); A shuttle valve (8), arranged in the shuttle valve hole of the reversing block LS load feedback oil passage.

2. The integrated load sensing proportional multi-way valve according to claim 1, wherein The outer end of the pressure control valve sleeve (401) is fixedly and sealingly connected to the pressure control valve body (404); The pressure control valve seat (403) is fixedly and sealingly connected to the inner end of the pressure control valve sleeve (401); A pressure control sliding cavity adapted to the pressure control spool (402) is formed between the pressure control valve sleeve (401) and the pressure control valve seat (403).

3. The integrated load-sensing proportional multi-way valve according to claim 2, wherein The cross section of the pressure control spool (402) is in a T-shaped structure, one end is located in the pressure control sliding cavity, and the other end extends out from the through hole in the middle of the pressure control valve seat 403, used for propping up the main spool (2).

4. An integrated load sensing proportional multi-way valve according to claim 1, characterized in that, The pressure compensator (3) includes a compensating spool (301), its first end is in pressure communication with the P oil passage, and its second end is communicated with the load pressure chamber (303) through a compensating spring (302).

5. An integrated load-sensing proportional multi-way valve according to claim 1, characterized in that, The spring cover (5) is internally provided with: A reset inner spring (53), with a stiffness coefficient of 0.5 - 1.2 N / mm, configured to provide the reset force for the main spool (2) in the pressure control mode; The electrically controlled outer spring (54) has a stiffness coefficient of 30-35 N / mm and is configured to form a displacement-force balance relationship with the pilot pressure in the flow control mode.

6. The integrated load sensing proportional multi-way valve according to claim 1, wherein The pressure control valve assembly (4) and the proportional pressure reducing valve (6) work together. In the pressure control mode, the pressure at the oil port A pushes back the main valve core (2) through the pressure control valve core (402), and realizes force closed-loop control with the pilot pressure. In the flow control mode, the displacement of the main valve core (2) is determined by the combined force of the pilot pressure and the electric control external spring (54), and ΔP is maintained constant through the pressure compensator (3).

7. A control method for an integrated load-sensing proportional multi-way valve, including an integrated pressure control and flow control load-sensing proportional multi-way valve as described in claim 1, characterized in that, include: ‌ In the neutral state, the pilot control oil in the spring cover (5) and the pressure control valve body (404) flows through the T oil circuit respectively, and the LS load feedback pressure is connected to the R oil circuit through the main valve core (2), thereby unloading the LS load feedback oil circuit. At this time, the A oil port, the B oil port, the P oil circuit and the R oil circuit are all blocked; In the pressure control mode, the pressure at port A is directly compared with the pilot pressure output by the proportional pressure reducing valve (6) through the pressure control valve assembly (4); In the flow control mode, the ΔP at both ends of the main valve core (2) is dynamically adjusted by the pressure compensator (3), so that the flow rate is determined only by the displacement of the main valve core.

8. A control method for an integrated load-sensitive proportional multi-way valve according to claim 7, characterized in that In pressure control state; When the coil A of the electromagnet (7) is energized, the push rod of the coil A of the electromagnet (7) pushes the valve core of the proportional pressure reducing valve to the left, causing the pilot control oil circuit to output pressure to the spring cover (5). The magnitude of the output pressure is proportional to the magnitude of the current flowing through the coil A of the electromagnet (7); Under the control of the pilot control oil pressure, the main valve core (2) moves to the left, so that the P oil circuit is connected to the A oil port, and the R oil circuit is connected to the B oil port; the pressure of the A oil port is fed back to the shuttle valve (8) through the main valve core (2) to compare the load pressure with other reversing links. The shuttle valve feeds back the higher load pressure to the variable pump to realize the load-sensitive control function. At the same time, the pressure of the A oil port is fed back to the pressure control valve assembly (4), so that the pressure control valve core (402) moves to the right and contacts the main valve core (2). The left side of the main valve core (2) is pushed by the pressure control valve core (402), and the right side is pushed by the pilot control oil pressure. The thrust of the left pressure control valve core = the pressure of the oil port A * the diameter area of the pressure control valve core; The force on the right main valve core = pilot control oil pressure * the diameter area of the main valve core and the spring force of the return inner spring; When comparing the forces on the left and right sides of the main valve core (2): When the force on the left side is greater, the pressure control valve core (402) pushes the main valve core to the right, cutting off the P oil circuit and the A oil port; When the force on the right side is larger, the pilot control oil pressure pushes the main valve core (2) to move to the left, increasing the flow area between the P oil circuit and the A oil circuit, achieving a dynamic balance of forces on both sides, thereby changing the magnitude of the pilot control oil pressure by controlling the magnitude of the current flowing through the coil A of the electromagnet (7), thereby controlling the magnitude of the output pressure of the A oil port; at this time, the P oil circuit is connected to the control chamber of the pressure compensator (3) through the main valve core (2), and the pressure on both sides of the pressure compensator (3) is the P oil circuit pressure. Under the action of the spring force, the pressure compensator (3) is in a normally open state.

9. A control method for an integrated load-sensing proportional multi-way valve according to claim 7, characterized in that, In flow control state; When the coil B of the electromagnet (7) is energized, the push rod of the coil B of the electromagnet (7) pushes the spool of the proportional pressure reducing valve II to move in the left direction, so that the pilot control oil circuit outputs pressure to the right chamber of the pressure control valve body, and the magnitude of the output pressure is proportional to the magnitude of the energizing current of the coil B of the electromagnet (7); Under the control of the pilot control oil pressure, the main spool (2) moves to the right, the P oil circuit is communicated with the B oil port, and the R oil circuit is communicated with the A oil port; the pressure of the B oil port is fed back to the shuttle valve (8) through the main spool (2), and is compared with the load pressure of other commutation joints. The shuttle valve feeds back the higher load pressure to the variable pump to realize the load sensing control function, and at the same time feeds back to the pressure control valve assembly (4), so that the pressure control spool (402) moves to the right. At this time, the main spool also moves to the right, so the pressure control spool (402) does not contact the main spool (2).

10. The control method of an integrated load-sensing proportional multi-way valve according to claim 9, characterized in that, The left side of the main spool (2) is subject to the pilot control oil pressure, and the right side is subject to the spring forces of the electric control outer spring (54) and the return inner spring (53); The force on the left side of the main spool = the pilot control oil pressure * the cross-sectional area of the through-hole of the main spool; When comparing the forces on the left and right sides of the main spool (2), the moving position of the main spool (2) is determined by the pilot control oil pressure, and the pilot control oil pressure is determined by the magnitude of the current of the electromagnet wire (7) coil B; The LS load feedback oil circuit communicates the pressure of the B oil port with the control chamber of the pressure compensator (3) through the main spool (2). The pressure on the right side of the pressure compensator (3) is the pressure of the P oil circuit, and the pressure on the left side is the pressure of the B oil port and the spring force of the pressure compensator (3); By comparing the pressures on the left and right sides, the communication and closing of the spool of the pressure compensator (3) are controlled, so as to control the pressure difference on both sides of the opening of the main spool (2) to always be maintained at 6-7 bar, so as to realize that the output flow of the main spool (2) is only related to the opening size of the main spool (2).

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