Bidirectional electromagnetic pressure-maintaining unloading valve

Abstract

The application relates to a bidirectional electromagnetic pressure-maintaining unloading valve, which comprises a three-position four-way electromagnetic reversing valve provided with an a-side electromagnet, a b-side electromagnet, an A channel, a B channel, a P channel and a T channel, and further comprises a main valve body provided with A1 and B1 inlet and outlet oil port channel cavities, A2 and B2 inlet and outlet oil port channel cavities, an oil inlet P and an oil return T; two hydraulic control one-way valves arranged between the A1 and B1 inlet and outlet oil port channel cavities and between the A2 and B2 inlet and outlet oil port channel cavities respectively. The application can be used for bypass unloading oil return in a bidirectional high-pressure large-flow hydraulic system hydraulic circuit, and can be used for zero-leakage bidirectional pressure-maintaining, impact-free unloading oil return in cooperation with a large-flow ''Y'' function or ''H'' function spool type directional valve.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to a bidirectional electromagnetic pressure-maintaining unloading valve. BACKGROUND

[0002] At present, the pressure-maintaining unloading valve in the prior art is usually of a single-channel type, and the pressure is usually 31.5 MPa. The unloading impact is large in high-pressure and large-flow applications. Some high-pressure applications cannot select a suitable valve, and have to select a manual ball valve operation instead.

[0003] Due to the low pressure and large impact in the prior art, the valve cannot be selected for a high-pressure and large-flow system above 40 MPa, especially needs to be installed in two parts in a bidirectional hydraulic circuit, so that the overall hydraulic system is not compact in structure, has poor integration, and is not convenient to install.

[0004] Therefore, a bidirectional electromagnetic pressure-maintaining unloading valve is urgently needed to solve a series of problems such as the need for a double-channel, bidirectional pressure-maintaining, impact-free unloading oil return in a high-pressure and large-flow application in a hydraulic system hydraulic circuit. SUMMARY

[0005] The present application aims at the above problems in the prior art, and provides a bidirectional electromagnetic pressure-maintaining unloading valve.

[0006] In order to achieve the above application purpose, the present application adopts the following technical scheme: the bidirectional electromagnetic pressure-maintaining unloading valve comprises a three-position four-way electromagnetic reversing valve provided with an a-side electromagnet, a b-side electromagnet, an A channel, a B channel, a P channel and a T channel, and further comprises:

[0007] a main valve body provided with an A1 inlet and outlet oil port channel cavity and a B1 inlet and outlet oil port channel cavity in communication with the A channel, an A2 inlet and outlet oil port channel cavity and a B2 inlet and outlet oil port channel cavity in communication with the B channel, an oil inlet P in communication with the P channel, and an oil return T in communication with the T channel, the oil inlet P being connected to a pressure oil source, and the oil return T being connected to an oil tank;

[0008] two hydraulic control one-way valves respectively arranged between the A1 inlet and outlet oil port channel cavity and the B1 inlet and outlet oil port channel cavity and between the A2 inlet and outlet oil port channel cavity and the B2 inlet and outlet oil port channel cavity;

[0009] wherein the A1 inlet and outlet oil port channel cavity and the B1 inlet and outlet oil port channel cavity form a first channel, and the A2 inlet and outlet oil port channel cavity and the B2 inlet and outlet oil port channel cavity form a second channel;

[0010] when the three-position four-way electromagnetic reversing valve is in the middle position, under the action of the two hydraulic control one-way valves, the liquid flow in the direction from the A1 inlet and outlet oil port channel cavity to the B1 inlet and outlet oil port channel cavity and in the direction from the A2 inlet and outlet oil port channel cavity to the B2 inlet and outlet oil port channel cavity is cut off;

[0011] When the b side electromagnet of the three-position four-way electromagnetic reversing valve is electrified, the pressure oil source switches to the A channel, so that the hydraulic control check valve located at the a side is actuated to realize the bidirectional flow of the first channel, which is the first channel unloading function opening state.

[0012] When the a side electromagnet of the three-position four-way electromagnetic reversing valve is electrified, the pressure oil source switches to the B channel, so that the hydraulic control check valve located at the b side is actuated to realize the bidirectional flow of the second channel, which is the second channel unloading function opening state.

[0013] Further, each hydraulic control check valve is a spiral plug-in hydraulic control check valve and is symmetrically arranged on both sides of the main valve body.

[0014] This setting, the hydraulic control check valve is different from the ordinary check valve, which has an additional control oil way. When the control oil way is not connected to the pressure oil, the hydraulic control check valve works like an ordinary check valve, and the pressure oil only flows from the oil inlet to the oil outlet and cannot flow in the opposite direction. When the control oil way has a control pressure input, the piston rod moves to the right under the action of the pressure oil, and the single-way valve is opened by the piston rod, so that the oil inlet and outlet are connected. If the oil outlet is greater than the oil inlet, the oil can flow in the opposite direction. The spiral plug-in hydraulic control check valve can be more conveniently installed in the main valve body, and the structure is simple and easy to disassemble and maintain.

[0015] Further, each hydraulic control check valve is provided with a flange plug and a sealing ring, and each hydraulic control check valve is sealed in the main valve body through the flange plug and the sealing ring.

[0016] Further, the main valve core of each hydraulic control check valve is a ball valve core with pre-unloading.

[0017] Further, the main valve body is provided with an O-ring and a corresponding step, and the sealing between the oil inlets and outlets A1 and B1 and the sealing between the oil inlets and outlets A2 and B2 are realized through the close contact between the step and the shoulder of the main valve body mounting bottom hole, so as to form A1 oil inlet and outlet cavities and B1 oil inlet and outlet cavities and A2 oil inlet and outlet cavities and B2 oil inlet and outlet cavities. That is, the first channel and the second channel are respectively twisted into the main valve body mounting screw holes (the valve body is provided with an O-type sealing ring, and the sealing between the oil inlet and outlet channels is realized through the close contact between the valve body step and the shoulder of the main valve body mounting bottom hole).

[0018] Further, the main valve body is provided with a plurality of oil channel process hole plugs, and the control oil channels on the first channel and the second channel are sealed from the outside through the oil channel process hole plugs.

[0019] Further, the main valve body is provided with a plurality of mounting screw holes. The main valve body can be conveniently mounted on other components.

[0020] Further, the pre-unloading control ratio of each hydraulic control check valve is 10-26:1.

[0021] Further, the main valve body is made of 42CrMo, and the design pressure is 500 bar. The test pressure is not less than 630 bar.

[0022] Further, the cover plate is used to replace the three-position four-way electromagnetic reversing valve, and the cover plate is provided with an A port control oil channel threaded interface and a B port control oil channel threaded interface, which correspond to the control oil channels of the first channel and the second channel respectively, and the A port control oil channel threaded interface and the B port control oil channel threaded interface are respectively connected to the pressure oil source, the hydraulic control check valve damping hole and the main valve core piston channel.

[0023] According to the working condition requirements, the three-position four-way electromagnetic reversing valve can be removed, and then the cover plate is installed on the main valve body, and the A port control oil channel and the B port control oil channel are respectively connected to the variable pressure oil source, so as to realize remote control.

[0024] Working principle and beneficial effects: 1. Compared with the prior art, the bidirectional electromagnetic pressure maintaining and unloading valve can realize bidirectional pressure maintaining, high pressure unloading without impact, bypass unloading, and low pressure control high pressure in the bidirectional high pressure and large flow scene. The control oil way (the oil way in the three-position four-way electromagnetic reversing valve) and the main oil way (the first channel and the second channel) have two parts of oil ways which do not interfere with each other, the valve core control pressure ratio is large, and then the accumulator or the low pressure and small flow hydraulic pump can be used as the external pressure oil source, so as to realize the main oil way unloading and oil return in the A1 or A2 pressure maintaining state of the main oil way. In this working condition, energy can be saved, and production cost can be reduced;

[0025] 2. Compared with the prior art, when the three-position four-way electromagnetic reversing valve is in the middle position, under the action of the two hydraulic control check valves, after the liquid flow of the A1 inlet and outlet port channel cavity to the B1 inlet and outlet port channel cavity direction and the A2 inlet and outlet port channel cavity to the B2 inlet and outlet port channel cavity direction is cut off, the A1 inlet and outlet port channel cavity and the A2 inlet and outlet port channel cavity can be pressurized without leakage and pressure maintaining, thereby playing a pressure maintaining role.

[0026] 3. Compared with the prior art, in this application, when the external pressure oil source is connected to the b-side electromagnet of the three-position four-way solenoid directional valve through the oil inlet P and the oil return port T, the solenoid valve function is switched to P→A and B→T. The pressure oil pushes the a-side hydraulic control check valve to act through the control oil passage A. Under the condition of pressurization or pressure holding of the A1 oil inlet and outlet channel cavity, the hydraulic control check valve has a pre-unloading function. The oil inlet and outlet channel cavity of A1 can be unloaded and returned to the oil tank without impact from the B1 oil inlet and outlet channel cavity. When the electromagnet on side a of the three-position four-way solenoid directional valve is energized, the solenoid valve's directional function switches to P→B and A→T. The pressurized oil passes through control oil passage B and pushes the hydraulic control check valve on side b to operate. Subsequently, under the pressurized or pressure-holding state of the A2 inlet / outlet channel cavity, due to the pre-unloading function of the hydraulic control check valve, the oil inlet / outlet channel cavity of A2 can be unloaded and return to the oil tank without impact from the B2 inlet / outlet channel cavity. This function, through the directional switching of the three-position four-way solenoid valve, achieves bidirectional unloading and oil return.

[0027] Compared with the prior art, this application uses a spiral cartridge hydraulic control check valve as a component, which has the advantages of compact structure, good sealing performance, easy installation and maintenance, and zero leakage under high pressure. Combined with the overall structure of this application, the compactness of the structure can be further improved. In the hydraulic system, it is no longer necessary to install it separately, thus solving the problems of the prior art's non-compact structure, poor integration, inconvenient installation and use, and inability to meet the requirements of certain high-pressure, high-flow bidirectional external control systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention;

[0029] Figure 2 yes Figure 1 Oil circuit diagram;

[0030] Figure 3 yes Figure 1 The three views;

[0031] Figure 4 This is a schematic diagram of another embodiment of the present invention;

[0032] Figure 5 yes Figure 4 Oil circuit diagram;

[0033] Figure 6 yes Figure 4 The three views;

[0034] Figure 7 yes Figure 1 A magnified view of a portion of the image.

[0035] In the diagram, 1. Three-position four-way solenoid directional valve; 2. Control port B oil passage process hole plug; 4. First flange plug; 5. First damping hole; 6. Main valve body; 7. First screw cylinder; 8. First piston; 9. First return spring; 10. First main push rod; 11. First O-ring; 12. B2 inlet / outlet oil passage cavity; 13. First pre-unloading pin; 14. Second O-ring; 15. First main valve core; 16. First pre-unloading steel ball; 17. First spring seat; 18. First pagoda spring; 19. First spring seat nut; 20. A2 inlet / outlet oil passage cavity; 21. Return oil port T; 22. Inlet oil port P; 23. Control oil passage A oil passage process hole plug; 5. Second flange plug; 26. Second damping hole; 27. Second spiral cylinder; 28. Second piston; 29. ​​Second return spring; 30. Second main push rod; 31. Third O-ring; 32. B1 inlet / outlet channel cavity; 33. Second pre-unloading pin; 34. Fourth O-ring; 35. Second main valve core; 36. Second pre-release steel ball; 37. Second spring seat; 38. Second pagoda spring; 39. Second spring seat nut; 40. A1 inlet / outlet channel cavity; 41. First valve seat; 42. Second valve seat; 43. A-side electromagnet; 44. B-side electromagnet; 45. Mounting screw hole; 46. Cover plate; 47. A-port control oil passage; 48. B-port control oil passage. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0037] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0038] like Figures 1-3 as well as Figure 7 As shown, this bidirectional electromagnetic pressure-holding and unloading valve includes:

[0039] The three-position four-way solenoid directional valve 1 is equipped with an a-side electromagnet 43, a b-side electromagnet 44, an A channel, a B channel, a P channel, and a T channel.

[0040] In this embodiment, the three-position four-way solenoid directional valve 1 is a prior art product, readily available on the market. It serves as a switching element between the hydraulic control system and the electrical control system, utilizing the attraction of electromagnets at both ends to move the valve core, changing the flow of oil and thus reversing the actuator. "Three-position four-way" can be understood as follows: "Three-position" refers to the valve core's ability to change between three positions. "Four-way" refers to the ability to connect four oil ports in different ways. For example, this example uses a three-position four-way solenoid directional valve 1 with a "Y" functional valve core. The valve core can change between left, center, and right positions. When the valve core is in the center position, the P port channels are not connected, while channels A, B, and T are interconnected. When the valve core is in the left position, oil can enter through channel P and exit through channel A, while channels B and T are connected. When the valve core is in the right position, oil can enter through channel P and exit through channel B, while channels A and T are connected.

[0041] Therefore, its internal structure and principle are existing technologies and will not be elaborated here. This application utilizes its function and characteristics, namely, switching the direction through a three-position four-way solenoid directional valve 1 via an external pressure oil source. The product has the advantages of mature technology and low cost. Once damaged, it can be directly removed from the main valve body 6 for replacement, resulting in low maintenance costs and a simple structure.

[0042] The main valve body 6 is provided with an A1 inlet / outlet channel cavity 40 and a B1 inlet / outlet channel cavity 32 connected to channel A, an A2 inlet / outlet channel cavity 20 and a B2 inlet / outlet channel cavity 12 connected to channel B, an oil inlet port P22 connected to channel P, and an oil return port T21 connected to channel T. The oil inlet port P22 is connected to a pressure oil source, and the oil return port T21 is connected to an oil tank.

[0043] In this embodiment, the main valve body 6 is provided with an oil circuit that cooperates with the four channels of the three-position four-way solenoid directional valve 1, as well as a cavity for installing the hydraulic control check valve assembly.

[0044] Preferably, the main valve body 6 is made of high-strength alloy steel 42CrMo, which is heat-treated and then precision-machined. It is designed for a pressure of 500 bar and can withstand high-pressure, high-strength tests up to 630 bar, ensuring high safety.

[0045] Two hydraulically controlled check valves are respectively located between the A1 inlet / outlet channel cavity 40 and the B1 inlet / outlet channel cavity 32, and between the A2 inlet / outlet channel cavity 20 and the B2 inlet / outlet channel cavity 12.

[0046] In this embodiment, the two-way hydraulic control check valves can be existing products from German company Hawe or other manufacturers; no limitation is made here. This type of spiral cartridge hydraulic control check valve with pre-unloading function serves as the valve core of the main valve body 6. This valve core design offers advantages such as high pressure, mature technology, simple installation, convenient maintenance, compact structure, good sealing performance, and high integration. These advantages ensure the performance and reliability of this invention.

[0047] The difference between a hydraulically controlled check valve and a regular check valve is the addition of a control oil circuit. When the control oil circuit is not connected to pressurized oil, the hydraulically controlled check valve operates like a regular check valve, with pressurized oil flowing only from the inlet to the outlet and not in the reverse direction. When control pressure is input to the control oil circuit, the piston rod moves under the action of the pressurized oil, opening the check valve and connecting the inlet and outlet. If the outlet is larger than the inlet, the oil can flow in the reverse direction. Furthermore, the screw-insertion type hydraulically controlled check valve can be more easily installed within the main valve body 6, featuring a simple structure and convenient assembly and disassembly.

[0048] The pre-unloading valve core is a small ball-type check valve located inside the main valve core (the valve port is spherical), with the valve seat situated within the inner cavity of the main valve core. Before the main valve port opens, the small ball-type check valve opens first, creating an annular gap that acts as a throttling mechanism, achieving shock-free (pre)unloading.

[0049] Specifically, each spiral cartridge hydraulic check valve includes a damping orifice, a spiral cylinder, a piston, a return spring, a main push rod, an O-ring, a pre-unloading pin, a main valve core, a pre-unloading steel ball, a spring seat, a pagoda spring, and a spring seat nut, etc.

[0050] For example, the hydraulic control check valve located on side b includes a first damping orifice 5, a first spiral cylinder 7, a first piston 8, a first return spring 9, a first main push rod 10, a first O-ring 11, a first pre-unloading pin 13, a second O-ring 14, a first main valve core 15, a first pre-unloading steel ball 16, a first spring seat 17, a first pagoda spring 18, and a first spring seat nut 19, etc.

[0051] For example, the hydraulic control check valve located on side a includes a second damping orifice 26, a second spiral cylinder 27, a second piston 28, a second return spring 29, a second main push rod 30, a third O-ring 31, a second pre-unloading pin 33, a fourth O-ring 34, a second main valve core 35, a second pre-unloading steel ball, a second spring seat 37, a second pagoda spring 38, and a second spring seat nut 39, etc.

[0052] The first channel is formed by the oil inlet / outlet channel cavity 40 of A1 and the oil inlet / outlet channel cavity 32 of B1, and the second channel is formed by the oil inlet / outlet channel cavity 20 of A2 and the oil inlet / outlet channel cavity 12 of B2; that is, the two hydraulic check valves control the two channels separately.

[0053] Specifically, each pilot-operated check valve is externally fitted with a flange plug (first flange plug 4 and second flange plug 25), which seals each pilot-operated check valve within the main valve body 6. Furthermore, each pilot-operated check valve has an O-ring and a valve seat installed at its center, allowing the first and second channels to be isolated via the O-ring, valve seat, and main valve body 6, respectively. The valve seat is used to mount the pilot-operated check valve, and the O-rings (second O-ring 14 and fourth O-ring 34) are mounted on the valve seat (first valve seat 41 and second valve seat 42). Because this application uses a screw-type cartridge pilot-operated check valve, only two cartridge components need to be easily screwed into the mounting screw holes of the main valve body 6. The main valve body 6 has a step with (second O-ring 14 and fourth O-ring 34) installed on it. Through tight contact between the valve body step and the shoulder of the mounting hole in the main valve body 6, a seal is achieved between inlet / outlet ports A1 and B1, and between inlet / outlet ports A2 and B2. This forms two channels: a first channel (A1 and B1) and a second channel (A2 and B2).

[0054] That is, A1-B1 is the first channel, and A2-B2 is the second channel. The first channel is isolated by the fourth O-ring 34, the first valve seat 41, and the main valve body 6; the second channel is isolated by the second O-ring 14, the second valve seat 42, and the main valve body 6. This forms chambers A1 and B1, as well as chambers A2 and B2.

[0055] Preferably, the main valve body 6 is provided with multiple oil passage process hole plugs (control oil port B oil passage process hole plug 2 and control oil passage A oil passage process hole plug 23), which seal the oil passage process holes on the first channel and the second channel.

[0056] like Figure 1 Combination Figure 2 As shown in the schematic diagram, when the three-position four-way solenoid directional valve 1 is in the neutral position (when the electromagnet 43 on side a and the electromagnet 44 on side b are not energized), according to the characteristics of the hydraulic control check valve, under the action of the first pagoda spring 18 and the second pagoda spring 38, the fluid flow in the direction from A1 inlet / outlet channel cavity 40 to B1 inlet / outlet channel cavity 32 (A1→B1) and the direction from A2 inlet / outlet channel cavity 20 to B2 inlet / outlet channel cavity 12 (A2→B2) is cut off; in this state, the pressure in cavities A1 and A2 can be maintained without leakage, thereby playing a pressure-maintaining role.

[0057] When the electromagnet 44 on side b of the three-position four-way solenoid directional valve 1 is energized (left position), P→A is open and B→T is open. The pressure oil source switches to channel A, causing the hydraulic control check valve on side a to operate and achieve bidirectional flow in the first channel. This is the first channel unloading function open state; that is, the pressure oil source direction (oil inlet P22) switches to chamber A, passes through the control oil circuit on side a, enters the second damping orifice 26, pushes the second piston 28, the second main push rod 30, and the second pre-unloading pin 33, opens the second pre-release steel ball 36, and then opens the second main valve core 35, realizing flow through A1→B1 and B1→A1. This is the first channel unloading function open state. At this time, under the pressure or pressure holding state of chamber A1, because the second main valve core 35 has a pre-unloading function, chamber A1 can be unloaded and return oil to the oil tank without impact.

[0058] When the electromagnet 43 on side a of the three-position four-way solenoid directional valve 1 is energized (right position), P→B and A→T are connected, and the pressure oil source is switched to channel B. This causes the hydraulic control check valve on side b to operate, realizing bidirectional flow in the second channel. This is the second channel unloading function open state. That is, the pressure oil source direction (oil inlet P22) is to the B chamber, passes through the control oil circuit on side b, enters the first damping orifice 5, pushes the first piston 8, the first main push rod 10, and the first pre-unloading pin 13, opens the first pre-unloading steel ball 16, and then opens the first main valve core 15, realizing flow between A2 and B2, and flow between B2 and A2. This is the second channel unloading function open state. At this time, under the pressure or pressure holding state of the A2 chamber, due to the pre-unloading function of the first main valve core 15, the A2 chamber can be unloaded and return oil to the oil tank without impact.

[0059] Thus, it can be seen that the valve body of this application can achieve multiple functions such as bidirectional pressure holding and shock-free unloading after the pressure oil source is switched by the three-position four-way solenoid directional valve 1.

[0060] Please see Figures 4-6 In other embodiments, depending on the operating conditions, the three-position four-way solenoid valve can be removed, and the cover plate 46 can be connected to the screw hole 47 corresponding to the control oil passage of port A and the screw hole 48 corresponding to the control oil passage of port B through an external pipeline. The control pressure oil source can be remotely controlled (equivalent to moving the solenoid valve to another location and connecting ports A and B with a hose). It is also possible to remotely control both ends to open the valve core simultaneously for unloading.

[0061] It also includes a cover plate 46, which is used to replace the three-position four-way solenoid directional valve 1 (with the same installation dimensions). The cover plate 46 is provided with a screw hole 47 for the A-port control oil passage and a screw hole 48 for the B-port control oil passage, while the P-port and T-port are sealed. Screw holes 47 and 48 are used to connect the corresponding first and second channel external control pipelines, respectively. That is, when the A-port control oil passage 47 is connected to the pressure oil source, the oil passage through the A-cavity leads to the second damping hole 26, pushing the second piston 28, the second main push rod 30, and the second pre-unloading pin 33 to open the second pre-release steel ball 36 and then open the second main valve core 35. A1→B1 flow and B1→A1 flow. At this time, under the pressure-pressurized or pressure-holding state of the A1 cavity, due to the pre-unloading function of the main valve core, the A1 cavity can be unloaded and return oil to the oil tank without impact.

[0062] When the B-port control oil passage 48 is connected to the pressure oil source, the oil flows through the B-chamber oil passage to the first damping orifice 5, pushing the first piston 8, the first main push rod 10, and the first pre-unloading pin 13 to open the first pre-unloading steel ball 16, after which the first main valve core 15 opens. Flow is then allowed from A2 to B2 and from B2 to A2. At this time, under the pressure-pressurized or pressure-holding state of the A2 chamber, due to the pre-unloading function of the main valve core, the A2 chamber can unload and return oil to the oil tank without impact.

[0063] The parts of this invention not described in detail are prior art, therefore they are not described in detail here.

[0064] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0065] Although this paper extensively uses the following components: 1. Three-position four-way solenoid directional valve; 2. Control port B oil passage process hole plug; 3. First flange plug; 4. First damping hole; 5. Main valve body; 6. First screw cylinder; 7. First piston; 8. First return spring; 9. First main push rod; 10. First O-ring; 11. B2 inlet / outlet channel cavity; 12. First pre-unloading pin; 13. Second O-ring; 14. First main valve core; 15. First pre-unloading steel ball; 16. First spring seat; 17. First pagoda spring; 18. First spring seat nut; 19. A2 inlet / outlet channel cavity; 20. Return oil port T21. Inlet oil port P22. Control oil passage A oil passage process hole plug; 23. Second flange plug 25. Second damping hole; 26. Second spiral cylinder; 27. Second piston; 28. Second return spring; 29. ​​Second main push rod; 30. Third O-ring; 31. B1 inlet / outlet channel cavity; 32. Second pre-unloading pin; 33. Fourth O-ring; 34. Second main valve core; 35. Second pre-release steel ball; 36. Second spring seat; 37. Second pagoda spring; 38. Second spring seat nut; 39. A1 inlet / outlet channel cavity; 40. First valve seat; 41. Second valve seat; 42. A-side electromagnet; 43. B-side electromagnet; 44. Mounting screw hole; 45. Cover plate; 46. A-port control oil passage; 47. B-port control oil passage; 48. etc., but the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0066] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to that of this application falls within the protection scope of this invention.

Claims

1. A two-way electromagnetic pressure-holding and unloading valve, comprising a three-position four-way electromagnetic directional valve, equipped with an a-side electromagnet, a b-side electromagnet, an A channel, a B channel, a P channel, and a T channel, characterized in that, Also includes: The main valve body is provided with an A1 inlet / outlet channel cavity and a B1 inlet / outlet channel cavity connected to channel A, an A2 inlet / outlet channel cavity and a B2 inlet / outlet channel cavity connected to channel B, an inlet port P connected to channel P, and a return port T connected to channel T. The inlet port P is connected to a pressure oil source, and the return port T is connected to an oil tank. Two hydraulically controlled check valves are respectively located between the A1 inlet / outlet channel cavity and the B1 inlet / outlet channel cavity, and between the A2 inlet / outlet channel cavity and the B2 inlet / outlet channel cavity; The A1 oil inlet / outlet channel cavity and the B1 oil inlet / outlet channel cavity form the first channel, and the A2 oil inlet / outlet channel cavity and the B2 oil inlet / outlet channel cavity form the second channel. When the three-position four-way solenoid directional valve is in the neutral position, under the action of the two hydraulic check valves, the flow of liquid in the direction from the A1 inlet / outlet channel to the B1 inlet / outlet channel and from the A2 inlet / outlet channel to the B2 inlet / outlet channel is cut off. When the electromagnet on side b of the three-position four-way solenoid directional valve is energized, the pressure oil source switches to channel A, causing the hydraulic control check valve on side a to operate and realize bidirectional flow in the first channel. This is the first channel unloading function open state. When the electromagnet on side a of the three-position four-way solenoid directional valve is energized, the pressure oil source switches to channel B, causing the hydraulic control check valve on side b to operate and realize bidirectional flow in the second channel. This is the second channel unloading function open state.

2. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 1, characterized in that, Each of the aforementioned hydraulic control check valves is a spiral-type cartridge hydraulic control check valve, and is symmetrically arranged on both sides of the main valve body.

3. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 2, characterized in that, Each of the hydraulic control check valves is provided with a flange plug, which seals each hydraulic control check valve in the mounting hole of the main valve body, isolating it from the outside.

4. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 2, characterized in that, The main valve core of each of the hydraulic control check valves is a pre-unloaded ball valve core.

5. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 1, characterized in that, The main valve body is provided with an O-ring and a corresponding step. Through the tight contact between the step and the mounting bottom hole shoulder of the main valve body, the sealing between the oil inlet and outlet ports A1 and B1 and the oil inlet and outlet ports A2 and B2 are achieved, thereby forming the oil inlet and outlet chambers A1 and B1, as well as the oil inlet and outlet chambers A2 and B2.

6. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 1, characterized in that, The main valve body is provided with multiple oil passage process hole plugs, which are used to seal the first channel control oil passage and the second channel control oil passage from the outside.

7. The bidirectional electromagnetic pressure-holding and unloading valve according to claim 1, characterized in that, The main valve body is provided with multiple mounting screw holes.

8. The bidirectional electromagnetic pressure-holding and unloading valve according to any one of claims 1-7, characterized in that, The pre-unloading ratio of each of the hydraulically controlled check valves is 10 to 26:

1.

9. The bidirectional electromagnetic pressure-holding and unloading valve according to any one of claims 1-7, characterized in that, The main valve body is made of 42CrMo material.

10. The bidirectional electromagnetic pressure-holding and unloading valve according to any one of claims 1-7, characterized in that, It also includes a cover plate, which is used to replace the three-position four-way solenoid directional valve. The cover plate is provided with an A-port control oil passage threaded interface and a B-port control oil passage threaded interface, which are respectively connected to the control oil passages of the first channel and the second channel. The A-port control oil passage threaded interface and the B-port control oil passage threaded interface are respectively connected to the pressure oil source to the damping hole of the hydraulic check valve to the main valve core piston channel.

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