A load-sensitive multi-way valve group

Abstract

A load-sensitive multi-way valve group includes an oil inlet and return valve body, a reversing valve body and a pressure reducing valve body. The oil inlet and return valve body is provided with an oil inlet port P, an oil return port T, a pressure feedback port LS, a main safety valve, an LS relief valve and a damping valve. The pressure feedback port LS is connected to the oil return port T through the LS relief valve and the damping valve respectively; the reversing valve body is provided with two working oil ports, the reversing valve body is provided with a main valve stem, a pressure compensation valve core and two secondary relief valves, the main valve stem and the reversing valve body form a three-position five-way reversing valve, and the pressure compensation valve core and the reversing valve body form a three-position six-way hydraulic control valve; its A and B ports are respectively connected to the two working oil ports, and the C port is connected to the other end of the pressure compensation valve core and the pressure feedback port LS; the control oil port k of the secondary relief valve is respectively connected to the working oil port. The valve group can accurately control the output flow to match the movement speed of the actuator, and no excess pressure oil higher than the main safety valve flows back to the oil tank, thereby achieving high efficiency and energy saving.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic valves, and in particular to a load-sensitive multi-way valve group. Background Art

[0002] With the continuous development of hydraulic transmission technology, hydraulic components have been widely used in various mainframes and technical equipment. Construction machinery is the largest market for hydraulic components. As a control element, the multi-way valve group is the core component of the hydraulic system of construction machinery and has a significant impact on the overall performance of the mainframe.

[0003] In recent years, construction machinery has been developing towards environmental protection and energy conservation, and hydraulic systems are crucial for achieving these goals. Traditional throttling and speed-regulating hydraulic systems are no longer sufficient for the mainframe. Consequently, load-sensing hydraulic systems are gaining widespread application in construction machinery. Their greatest advantages are high efficiency and energy savings, improving mainframe control performance. Load-sensing valve blocks are key components of this new hydraulic system and represent a high-end manufacturing capability.

[0004] Currently, the front-end valves used in domestic engineering machinery primarily rely on foreign manufacturers such as Germany's Rexroth and Harwe, and the United States' Danfoss. There is a huge demand for import substitution, and at the same time, imported products still have room for technical improvement. Therefore, developing a superior performance main control valve group for engineering machinery is extremely important, both to replace imports and further promote the upgrading of host machine technology.

[0005] Currently, load-sensing hydraulic valves produced by foreign manufacturers can be structurally divided into two categories: pre-valve compensating load-sensing hydraulic valves and post-valve compensating load-sensing hydraulic valves. Both types share the common characteristic of controlling the hydraulic pump output flow rate through load pressure feedback (LS signal) to optimally match it with the actuator's motion. The former differs in that it features an LS relief function, making the system more energy-efficient, but lacks flow sharing. In other words, insufficient output flow during compound operation will cause the actuator on the side with the greater load to cease operation. The latter allows flow sharing independent of system output, allowing the actuator to move proportionally during compound operations regardless of load. However, it lacks an LS relief function, resulting in excessive energy loss when the actuator is overloaded, causing system heating.

[0006] In view of the above reasons, developing a load-sensitive valve group with complementary and compatible pre-valve compensation and post-valve compensation functions will inevitably become the commanding heights of the industry's technological competition. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a load-sensitive multi-way valve group, which can accurately control the output flow of the hydraulic system so that it matches the movement speed of the actuator, and no excess pressure oil higher than the main safety valve flows back to the oil tank, thereby reducing the overflow of the hydraulic system and achieving high efficiency and energy saving.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A load-sensing multi-way valve group includes an oil inlet and return valve body, a reversing valve body, and a pressure reducing valve body with a built-in pressure reducing valve, which are connected in sequence. The oil inlet and return valve body is provided with an oil inlet port P, an oil return port T, a pressure feedback port LS, and is also equipped with a main safety valve, an LS relief valve 2, and a damping valve. The oil inlet port P is connected to the oil return port T through the main safety valve, and the pressure feedback port LS is connected to the oil return port T through the LS relief valve 2 and the damping valve respectively.

[0010] There are two working oil ports on the reversing valve body, and the main valve stem, pressure compensation valve core and two secondary relief valves are installed in the reversing valve body. The main valve stem and the reversing valve body form a three-position five-way reversing valve, and the pressure compensation valve core and the reversing valve body form a three-position six-way hydraulic control valve.

[0011] The P and T ports of the three-position five-way directional control valve are connected to the oil inlet P and the oil return port T, respectively; the A and B ports are connected to the P and T ports of the three-position six-way hydraulic control valve, respectively; and the C port is connected to the P1 port of the three-position six-way hydraulic control valve, the control oil chamber at one end of the pressure compensation valve core, and the oil inlet i of the two secondary relief valves, respectively; when the three-position five-way directional control valve is in the middle position, its A, B, and C ports are all connected to the T port; when the three-position five-way directional control valve is in the two end positions, its C port is connected to the A and B ports, respectively;

[0012] The A and B ports of the three-position six-way hydraulic control valve are connected to the two corresponding working oil ports respectively, and the C port is connected to the reset oil chamber at the other end of the pressure compensation valve core and the pressure feedback port LS; the control oil ports k of the two secondary relief valves are connected to the two corresponding working oil ports respectively; when the pressure of one of the working oil ports is greater than the set pressure of the secondary relief valve, the secondary relief valve corresponding to the working oil port opens, and the oil inlet i is connected to the oil return port T through the secondary relief valve.

[0013] As a further preference, when the three-position six-way hydraulic control valve is in the initial lower position, each port is cut off; when it is in the working upper position, its P port is connected to the A port, the B port is connected to the T port, and the P1 port is connected to the C port; when it is in the working middle position, its P port is throttled and connected to the A port, the B port is throttled and connected to the T port, and the P1 port is cut off from the C port; when it is used to connect two or more actuators for compound action, it can achieve speed control that is independent of the load.

[0014] As a further preference, valve covers are respectively provided on both sides of the reversing valve body, and both ends of the main valve stem are respectively inserted into the valve covers; a proportional solenoid valve is installed on one of the valve covers, and the proportional solenoid valve is composed of two oil inlet valves installed in the right valve cover and an explosion-proof proportional electromagnet fixed on the right valve cover, the oil inlet chambers of the two oil inlet valves are respectively connected to the oil outlet of the pressure reducing valve, and the oil outlets of the two oil inlet valves are respectively connected to the main valve stem chambers in the valve covers on both sides; the explosion-proof proportional electromagnet has two solenoid valve cores and corresponds to the two oil inlet valves, respectively, for selectively controlling the conduction of the two oil inlet valves, thereby controlling the reversing of the three-position five-way reversing valve.

[0015] As a further preference, the reversing valve body consists of three pieces and is sequentially arranged between the oil inlet and return valve body and the pressure reducing valve body, for respectively connecting and controlling a plurality of actuators.

[0016] As a further preference, the secondary relief valve includes a valve sleeve and valve core, a sealing cover, an adjusting spring and an adjusting screw that are matched through a sliding clearance. The valve sleeve is inserted into the mounting hole on the top surface of the reversing valve body and is limited by the sealing cover. The adjusting screw is installed in the center hole of the sealing cover through a thread. The adjusting spring is clamped between the adjusting screw and the valve core to adjust the opening pressure of the secondary relief valve.

[0017] As a further preference, the control oil port k and the oil inlet i are radially arranged up and down on the valve sleeve, and an annular groove is provided in the middle of the valve core corresponding to the control oil port k, and the outer edge diameter of the valve core above the annular groove is larger than the outer edge diameter below the annular groove, so that the cross-sectional area of ​​the annular shoulder at the upper end of the annular groove is larger than the cross-sectional area of ​​the annular shoulder at the lower end of the annular groove, so that when the pressure difference acting on the two ends of the annular groove on the valve core is greater than the pressure of the adjusting spring, the valve core of the secondary relief valve is moved upward and opened.

[0018] As a further preference, an annular unloading oil chamber is provided between the lower end of the valve sleeve and the mounting hole on the top surface of the reversing valve body, an oil drain hole is provided radially at the lower end of the valve sleeve, and an oil return channel tangentially connected to the unloading oil chamber is provided on the reversing valve body. When the valve core of the secondary relief valve moves upward and opens, the oil inlet i is connected to the oil return port T through the inner hole of the valve sleeve, the oil drain hole, the unloading oil chamber and the return oil channel in sequence.

[0019] As a further preference, the pressure reducing valve is a cartridge-type pressure reducing valve and is installed in the pressure reducing valve body through threads. The oil inlet of the pressure reducing valve is connected to the oil inlet P through an oil channel and the P port of the three-position five-way reversing valve provided on the reversing valve body. The oil outlet of the pressure reducing valve is connected to the oil inlet chamber of each of the oil inlet valves through oil channels provided on the pressure reducing valve body and the reversing valve body.

[0020] The beneficial effects of the present invention are:

[0021] 1. This valve group and the variable piston pump form a hydraulic system. The pressure compensation valve core provided in the reversing valve body and the reversing valve body form a three-position six-way hydraulic control valve. Its C port is connected to the reset oil chamber at the other end of the pressure compensation valve core and the pressure feedback port LS. Therefore, during operation, the oil inlet pressure of the oil inlet P can be fed back to the variable piston pump through the three-position five-way reversing valve and the three-position six-way hydraulic control valve via the pressure feedback port LS, thereby accurately controlling the output flow of the hydraulic system to match the movement speed of the actuator. No excess oil with a pressure higher than that of the main safety valve flows back to the oil tank, thereby reducing the overflow of the hydraulic system and achieving high efficiency and energy saving.

[0022] 2. Since two secondary relief valves are provided in the reversing valve body, the C port of the three-position five-way reversing valve is respectively connected to the P1 port of the three-position six-way hydraulic control valve, the control oil chamber at one end of the pressure compensation valve core and the oil inlet i of the two secondary relief valves, and the control oil port k of the two secondary relief valves is respectively connected to the two working oil ports; when the pressure of one of the working oil ports is greater than the set pressure of the secondary relief valve, the secondary relief valve corresponding to the working oil port opens, and the oil inlet i is connected to the return oil port T through the secondary relief valve. Therefore, the pressure of the pressure feedback port LS can be quickly adjusted by the secondary relief valve, and the flow of the oil inlet P and the working oil port is adjusted by the variable piston pump, so that the valve group achieves the optimal working state of high efficiency, energy saving and precise control, and has the advantages of compact structure and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 yes Figure 1 Bottom view of .

[0025] Figure 3 yes Figure 2 Left view of .

[0026] Figure 4 yes Figure 2 Right view of .

[0027] Figure 5 yes Figure 2 AA cross-sectional view.

[0028] Figure 6 yes Figure 2 BB cross-sectional view.

[0029] Figure 7 yes Figure 2 CC cross-sectional view.

[0030] Figure 8 yes Figure 6 A partial enlarged view of .

[0031] Figure 9 It is a hydraulic principle diagram of the present invention.

[0032] In the figure: oil inlet and return valve body 1, LS relief valve 2, secondary relief valve 3, connecting bolt 4, pressure reducing valve body 5, proportional solenoid valve 6, reversing valve body 7, mounting hole 701, oil return channel 702, control oil chamber 703, reset oil chamber 704, main safety valve 8, damping valve 9, main valve stem 10, left valve cover 11, reset spring 12, pressure compensation valve core 13, right valve cover 14, reset spring 15, pressure reducing valve 16, valve core 17, valve sleeve 18, oil drain hole 1801, sealing cover 19, nut 20, adjusting screw 21, adjusting spring 22, unloading oil chamber 23, three-position five-way reversing valve 24, three-position six-way hydraulic control valve 25. DETAILED DESCRIPTION

[0033] like Figures 1-9 As shown, the present invention relates to a load-sensitive multi-way valve group, including an oil inlet and return valve body 1, a reversing valve body 7 and a pressure reducing valve body 5 with a built-in pressure reducing valve 16, which are connected in sequence by connecting bolts 4. An oil inlet P and an oil return port T are provided on the top surface of the oil inlet and return valve body 1, and a pressure feedback port LS, an oil drain port Y and a pressure measuring port G are provided on the outer end surface of the oil inlet and return valve body 1. A main safety valve 8, an LS relief valve 2 and a damping valve 9 are respectively inserted into and threadedly installed in the oil inlet and return valve body 1. The oil inlet P is connected to the pressure measuring port G and is connected to the oil return port T through the main safety valve 8 and the oil channel provided in the oil inlet and return valve body 1. The pressure feedback port LS is connected to the oil return port T through the oil channel, the LS relief valve 2 and the damping valve 9 provided in the oil inlet and return valve body 1.

[0034] The reversing valve body 7 is composed of multiple pieces and is sequentially arranged and clamped between the oil inlet and return valve body 1 and the pressure reducing valve body 5, and is used to connect and control multiple actuators. This embodiment takes three reversing valve bodies 7 as an example.

[0035] Two working oil ports are respectively provided on the top surface of each reversing valve body 7. The working oil ports of the three reversing valve bodies 7 are A1, B1, A2, B2 and A3, B3 respectively. A main valve stem 10, a pressure compensating valve core 13 and two secondary relief valves 3 are respectively inserted in each reversing valve body 7. The main valve stem 10 and the corresponding reversing valve body 7 respectively form a three-position five-way reversing valve 24, and the pressure compensating valve core 13 and the corresponding reversing valve body 7 respectively form a three-position six-way hydraulic control valve 25.

[0036] The P and T ports of the three-position, five-way directional valve 24 on the three-piece directional valve body 7 are interconnected and connected to the oil inlet port P and oil return port T, respectively, via oil passages provided within the oil inlet and return valve body 1. The A and B ports of the three-position, five-way directional valve 24 are connected to the P and T ports of the corresponding three-position, six-way hydraulic control valve 25, respectively. Port C is connected to port P1 of the three-position, six-way hydraulic control valve 25, the control oil chamber 703 at one end of the pressure compensation valve core 13, and the oil inlet port i of the two secondary relief valves 3, respectively, via oil passages provided within the directional valve body 7 and the pressure compensation valve core 13. When the three-position, five-way directional valve 24 is in the neutral position, its A, B, and C ports are all connected to port T. When the three-position, five-way directional valve 24 is in either end position, its C port is connected to ports A and B, respectively.

[0037] Ports A and B of the three-position, six-way hydraulically controlled valve 25 communicate with the two corresponding working oil ports on the directional control valve body 7. Port C of the three-position, six-way hydraulically controlled valve 25 communicates with a reset oil chamber 704 at the other end of the pressure compensating valve core 13 via an oil passage within the pressure compensating valve core 13, and also communicates with the pressure feedback port LS via an oil passage. A reset spring 12 is provided within the reset oil chamber 704, located between the pressure compensating valve core 13 and the corresponding left valve cover 11, to reset the pressure compensating valve core 13.

[0038] When the three-position six-way hydraulic control valve 25 is in the initial lower position, all ports are blocked; when in the working upper position, its P port is connected to the A port, the B port is connected to the T port, and the P1 port is connected to the C port; when in the working middle position, its P port is throttled and connected to the A port, the B port is throttled and connected to the T port, and the P1 port is blocked from the C port; when used to connect two or more actuators for compound action, it can achieve speed control that is independent of the load.

[0039] The control oil ports k of the two secondary relief valves 3 are respectively connected to the two working oil ports on the corresponding reversing valve body 7 through the oil channels provided in the reversing valve body 7; when the pressure of one of the working oil ports is greater than the set pressure of the secondary relief valve 3, the secondary relief valve 3 corresponding to the working oil port opens, and the oil inlet i is connected to the oil return port T through the secondary relief valve 3.

[0040] The secondary relief valve 3 includes a valve sleeve 18 and a valve core 17, a sealing cover 19, an adjusting spring 22 and an adjusting screw 21 that are matched through a sliding clearance. The valve sleeve 18 is inserted into the mounting hole 701 in the middle of the top surface of the reversing valve body 7 and is limited by the sealing cover 19. The sealing cover 19 is inserted into the upper mouth of the mounting hole 701 and is fixed to the reversing valve body 7 by screws. The adjusting screw 21 is threadedly installed in the center hole of the sealing cover 19 and a nut 20 is threadedly connected to the outer end of the adjusting screw 21. The adjusting spring 22 is clamped between the adjusting screw 21 and the valve core 17 to adjust the opening pressure of the secondary relief valve 3.

[0041] The control oil port k and the oil inlet i are arranged radially up and down on the valve sleeve 18, and an annular groove is provided in the middle of the valve core 17 corresponding to the control oil port k, and the outer edge diameter of the valve core 17 above the annular groove is larger than the outer edge diameter below the annular groove, so that the cross-sectional area of ​​the annular shoulder at the upper end of the annular groove is larger than the cross-sectional area of ​​the annular shoulder at the lower end of the annular groove. When the pressure difference acting on the two ends of the annular groove on the valve core 17 is greater than the pressure of the adjusting spring 22, the valve core 17 of the secondary relief valve 3 moves up and opens.

[0042] An annular unloading oil chamber 23 is provided between the lower end of the valve sleeve 18 and the lower end of the mounting hole 701 on the top surface of the reversing valve body 7. Oil drain holes 1801 are evenly distributed along the radial circumference of the lower end of the valve sleeve 18. An oil return channel 702 tangentially connected to the unloading oil chamber 23 is provided on the reversing valve body 7. When the valve core 17 of the secondary relief valve 3 moves upward to open, the oil inlet i is connected to the oil return port T through the inner hole of the valve sleeve 18, the oil drain hole 1801, the unloading oil chamber 23 and the return oil channel 702 in sequence.

[0043] A left valve cover 11 and a right valve cover 14 are connected to both sides of the reversing valve body 7 by screws, and both ends of the main valve stem 10 are respectively inserted into the main valve stem cavities of the left and right valve covers; a reset spring 15 is provided in the main valve stem cavity of the right valve cover 14 and is sleeved on the main valve stem 10, and both ends of the reset spring 15 are respectively sleeved on the main valve stem 10 through spring seats, so as to realize automatic reset of the main valve stem 10 when there is no pressure pilot oil.

[0044] A proportional solenoid valve 6 is mounted on the right valve housing 14. This solenoid valve 6 consists of two oil inlet valves mounted within the right valve housing 14 and an explosion-proof proportional electromagnet fixed to the right valve housing 14. The oil inlet chambers of the two oil inlet valves are connected to the oil outlets of the pressure reducing valve 16. The oil outlets of the two oil inlet valves are connected to the main valve stem chambers in the left and right valve housings via oil passages provided within the reversing valve body 7 and the left and right valve housings, respectively. The explosion-proof proportional electromagnet has two solenoid valve cores, each corresponding to the valve cores of the two oil inlet valves, to selectively control the conduction of the two oil inlet valves, thereby controlling the reversing direction of the three-position, five-way reversing valve 24.

[0045] The pressure-reducing valve 16 is a plug-in type pressure-reducing valve threadedly mounted within the pressure-reducing valve body 5. The oil inlet port f of the pressure-reducing valve 16 communicates with the oil inlet port P via an oil passage and port P of the three-position, five-way reversing valve 24 located on the reversing valve body 7. The oil outlet port c of the pressure-reducing valve 16 leads to a pressure measurement port X at the outer end of the pressure-reducing valve body 5 and communicates with the oil inlet chamber of each of the oil inlet valves via oil passages g located within the pressure-reducing valve body 5, the reversing valve body 7, and the right valve housing 14, respectively, to transfer the reduced-pressure oil to the two oil inlet valves. The oil drain ports of the proportional solenoid valve 6 and the pressure-reducing valve 16 communicate with the oil drain port Y via oil passages located within the reversing valve body 7.

[0046] During operation, connect the oil inlet P and pressure feedback port LS to the oil outlet and feedback port of the variable displacement piston pump, respectively. Connect the oil return port T and drain port Y to the fuel tank. Connect the operating oil ports A1 and B1 on the reversing valve body 7 to the actuator. The main safety valve 8 allows manual pressure adjustment according to system requirements. The damping valve 9 suppresses significant vibration in the pipeline or equipment, reducing its amplitude and thus protecting it. When the system is shut down, the high pressure at the pressure feedback port LS must be reduced to near zero pressure to minimize the displacement of the variable displacement piston pump. The damping valve 9 drains the high-pressure oil back to the fuel tank, gradually reducing the pressure at the pressure feedback port LS.

[0047] When the valve group is in standby state, the pressure at the pressure feedback port LS approaches zero, so that the displacement of the variable piston pump is at the minimum state and the output flow approaches zero.

[0048] When working Figure 9As shown, the position of the main valve stem 10 of the 5 / 3-way directional valve 24 is controlled by the proportional solenoid valve 6, thereby controlling the operation of the actuator. When the proportional solenoid valve 6 is de-energized, the main valve stem 10 is in the neutral position, and the pressure feedback port LS is pressureless, causing the variable pump displacement to approach zero and the valve block to be inoperative. When the proportional solenoid valve controls the main valve stem 10 downward, pressurized oil flows through the oil inlet P and the 5 / 3-way directional valve into the control oil chamber 703 at one end of the pressure compensation valve core 13, pushing the pressure compensation valve core 13 to the upper position. At this point, the pressurized oil flows through the 6 / 3-way hydraulic control valve 25 and outputs oil pressure through the working oil port B1, activating the actuator. Simultaneously, the pressurized oil returns to the pressure feedback port LS through the 6 / 3-way hydraulic control valve 25, ultimately feeding the pressure signal back to the variable pump. When the actuator is overloaded, the pressure of the working oil port B1 is greater than the set pressure of the corresponding secondary relief valve 3. The pressure oil entering the control oil port k acts on the valve core of the secondary relief valve 3, causing the valve core of the secondary relief valve 3 to move upward and open. At this time, the pressure feedback port LS connected to the oil inlet i of the secondary relief valve is unloaded through the secondary relief valve and the return oil port T, causing the pressure of the pressure feedback port LS to drop rapidly, thereby causing the variable piston pump to automatically adjust its output flow and reduce the flow of the oil inlet P and the working oil port. It can be seen that the load pressure of the working oil port can be adjusted by the set pressure of the secondary relief valve.

[0049] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A load-sensitive multi-way valve group, comprising an oil inlet and return valve body, a reversing valve body and a pressure reducing valve body with a pressure reducing valve installed therein, which are connected in sequence, and is characterized by: The oil inlet and return valve body is provided with an oil inlet port P, an oil return port T, a pressure feedback port LS, and is installed with a main safety valve, an LS relief valve and a damping valve. The oil inlet port P is connected to the oil return port T through the main safety valve, and the pressure feedback port LS is connected to the oil return port T through the LS relief valve and the damping valve respectively; There are two working oil ports on the reversing valve body, and a main valve stem, a pressure compensation valve core and two secondary relief valves are arranged in the reversing valve body. The main valve stem and the reversing valve body form a three-position five-way reversing valve, and the pressure compensation valve core and the reversing valve body form a three-position six-way hydraulic control valve. The P and T ports of the three-position five-way reversing valve are respectively connected to the oil inlet P and the oil return port T, the A and B ports are respectively connected to the P and T ports of the three-position six-way hydraulic control valve, and the C port is respectively connected to the P1 port of the three-position six-way hydraulic control valve, the control oil chamber at one end of the pressure compensation valve core and the oil inlet i of the two secondary relief valves; when the three-position five-way reversing valve is in the middle position, its A, B and C ports are all connected to the T port; when the three-position five-way reversing valve is in the two end positions, its C port is respectively connected to the A and B ports; The A and B ports of the three-position six-way hydraulic control valve are connected to two corresponding working oil ports respectively, and the C port is connected to the reset oil chamber at the other end of the pressure compensation valve core and the pressure feedback port LS; the control oil ports k of the two secondary relief valves are connected to two corresponding working oil ports respectively; when the pressure of one of the working oil ports is greater than the set pressure of the secondary relief valve, the secondary relief valve corresponding to the working oil port opens, and the oil inlet i is connected to the oil return port T through the secondary relief valve.

2. A load-sensing multi-way valve assembly according to claim 1, characterized in that: When the three-position six-way hydraulic control valve is in the initial lower position, each port is cut off; when it is in the working upper position, its P port is connected to the A port, the B port is connected to the T port, and the P1 port is connected to the C port; when it is in the working middle position, its P port is throttled to the A port, the B port is throttled to the T port, and the P1 port is cut off from the C port; when it is used to connect two or more actuators for compound action, it can achieve speed control that is independent of the load.

3. A load-sensing multi-way valve assembly according to claim 1, characterized in that: Valve covers are respectively provided on both sides of the reversing valve body, and both ends of the main valve stem are respectively inserted into the valve covers; a proportional solenoid valve is installed on one of the valve covers, and the proportional solenoid valve is composed of two oil inlet valves installed in the right valve cover and an explosion-proof proportional electromagnet fixed on the right valve cover, and the oil inlet chambers of the two oil inlet valves are respectively connected to the oil outlet of the pressure reducing valve, and the oil outlets of the two oil inlet valves are respectively connected to the main valve stem chambers in the valve covers on both sides; the explosion-proof proportional electromagnet has two solenoid valve cores and corresponds to the two oil inlet valves respectively, for selectively controlling the conduction of the two oil inlet valves, thereby controlling the reversing of the three-position five-way reversing valve.

4. A load-sensing multi-way valve assembly according to claim 3, characterized in that: The reversing valve body is composed of three pieces and is arranged in sequence between the oil inlet and return valve body and the pressure reducing valve body, and is used to connect and control multiple actuators respectively.

5. The load-sensing multi-way valve assembly according to claim 1 is characterized in that: The secondary relief valve includes a valve sleeve and a valve core, a sealing cover, an adjusting spring and an adjusting screw that are matched through a sliding clearance. The valve sleeve is inserted into the mounting hole on the top surface of the reversing valve body and is limited by the sealing cover. The adjusting screw is installed in the center hole of the sealing cover through a thread. The adjusting spring is clamped between the adjusting screw and the valve core to adjust the opening pressure of the secondary relief valve.

6. A load-sensing multi-way valve assembly according to claim 5, characterized in that: The valve sleeve is radially provided with the control oil port k and the oil inlet port i which are arranged up and down, and an annular groove is provided in the middle of the valve core corresponding to the control oil port k, and the outer edge diameter of the valve core located above the annular groove is larger than the outer edge diameter below the annular groove, so that the cross-sectional area of ​​the annular shoulder at the upper end of the annular groove is larger than the cross-sectional area of ​​the annular shoulder at the lower end of the annular groove, so that when the pressure difference acting on the two ends of the annular groove on the valve core is greater than the pressure of the adjusting spring, the valve core of the secondary relief valve is moved up and opened.

7. A load-sensing multi-way valve assembly according to claim 6, characterized in that: An annular unloading oil chamber is provided between the lower end of the valve sleeve and the mounting hole on the top surface of the reversing valve body, an oil drain hole is radially provided at the lower end of the valve sleeve, and an oil return channel tangentially connected to the unloading oil chamber is provided on the reversing valve body. When the valve core of the secondary relief valve moves upward and opens, the oil inlet i is connected to the oil return port T through the inner hole of the valve sleeve, the oil drain hole, the unloading oil chamber and the oil return channel in sequence.

8. The load-sensing multi-way valve assembly according to claim 3 is characterized in that: The pressure reducing valve is a plug-in pressure reducing valve and is installed in the pressure reducing valve body by threads. The oil inlet of the pressure reducing valve is connected with the oil inlet P through an oil passage and the P port of a three-position five-way reversing valve arranged on the reversing valve body. The oil outlet of the pressure reducing valve is connected with the oil inlet chamber of each oil inlet valve through oil passages arranged on the pressure reducing valve body and the reversing valve body.

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