Pilot valve plunger sealing structure

Abstract

The invention relates to the technical field of hydraulic pressure, and discloses a pilot valve plunger sealing structure which comprises a pilot valve body, a pilot valve plunger is arranged in the pilot valve body in a sliding mode, the periphery of the pilot valve plunger is sleeved with a plunger guide sleeve, and a main sealing piece is arranged in the side, close to the pilot valve plunger, of the plunger guide sleeve in a sliding mode. The side, away from the plunger guide sleeve, of the main sealing piece abuts against a check ring, a plunger hole and a sealing hole are formed in the pilot valve body, a valve element is installed in the pilot valve body, and the periphery of the valve element is sleeved with a metering spring and a reset spring. The O-shaped sealing ring assists in static sealing and dynamic sealing, static sealing and dynamic sealing are achieved through the sealing piece formed by the fixing sleeve, the hydrogenated butadiene-acrylonitrile rubber of a special structure and the self-tightening spring, the multiple static sealing and dynamic sealing modes are adopted, the sealing performance of the plunger is improved, and the possibility of hydraulic oil leakage is reduced.

Description

Technical Field

[0001] The invention relates to the field of hydraulic technology, in particular to a pilot valve plunger sealing structure. Background Art

[0002] A pilot valve is a device that uses a smaller control signal (such as a hydraulic, pneumatic or electrical signal) to guide and control the action of the main valve or the entire system. It is a key component in hydraulic and pneumatic systems. Through the pilot valve, a small signal can be amplified to a large flow or high-pressure operation sufficient to drive the main valve, thereby achieving precise control of the system. It is characterized by rapid response, low energy consumption, compact structure, and is suitable for high-precision control of complex systems. Pilot valves are widely used in industrial automation, construction machinery, hydraulic equipment and pneumatic devices, such as the hydraulic system of excavators, pneumatic component control of factory automation, and various fluid control systems, which can significantly improve the control efficiency and stability of the equipment; The pilot valve plunger seal is a device used to seal the gap between the pilot valve plunger and the valve body. By using high-pressure and wear-resistant sealing materials (such as rubber, polyurethane or metal), it ensures that the plunger does not leak during movement and ensures that the flow path of the hydraulic or pneumatic medium is accurate. Its design can not only withstand high-pressure environments, but also reduce wear and increase service life. It is a key component for the stable operation and sealing performance of the pilot valve; In the hydraulic system, the quality of the pilot valve plunger seal directly affects the performance of the hydraulic system. For example, the precise control of the excavator's boom, dipper and other movements depends on the pilot valve. The plunger in the pilot valve moves frequently in the pilot valve body. When the hydraulic oil pushes the plunger to move through the control channel of the pilot valve, if the seal is not good, it will cause hydraulic oil leakage, making the system pressure unstable and causing the loader bucket to lift weakly or shake, affecting work efficiency and work quality. Early pilot valve plunger seal structures mostly used rubber seals. Traditional rubber seals will be corroded by hydraulic oil during long-term use, and will age, harden or swell. When the system pressure exceeds the limit that the rubber seal can withstand, the seal is easily squeezed out of the sealing groove, resulting in seal failure. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a pilot valve plunger sealing structure, which solves the problem that traditional sealing only uses O-ring rubber and skeleton sealing, and has a high risk of hydraulic oil leakage and seepage.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: a pilot valve plunger sealing structure, including a pilot valve body, a pilot valve plunger sliding inside the pilot valve body, a plunger guide sleeve sleeve arranged on the outer periphery of the pilot valve plunger, a main seal sliding inside the plunger guide sleeve on the side close to the pilot valve plunger, a retaining ring abutting against the side of the main seal away from the plunger guide sleeve, a plunger hole and a sealing hole are provided inside the pilot valve body, a valve core is installed inside the pilot valve body, a metering spring and a return spring are respectively sleeved on the outer periphery of the valve core, the metering spring and the return spring abut against a card gasket at one end close to the pilot valve plunger, and an open retaining ring is installed at the outer periphery of one end of the pilot valve plunger close to the valve core.

[0005] Preferably, a first O-ring is provided on a side of the plunger guide sleeve close to the pilot valve plunger, and a second O-ring is provided on a side of the plunger guide sleeve away from the pilot valve plunger.

[0006] Preferably, the main seal includes a fixed sleeve, which is arranged inside the plunger guide sleeve, and a hydrogenated nitrile rubber is arranged on the side of the fixed sleeve close to the pilot valve plunger, and a sealing upper lip and a sealing lower lip are respectively arranged on the side of the hydrogenated nitrile rubber close to the pilot valve plunger, and a self-tightening spring is arranged on the side of the hydrogenated nitrile rubber away from the pilot valve plunger.

[0007] Preferably, an inner sealing groove is provided inside the plunger guide sleeve, the first O-ring slides inside the inner sealing groove, an outer sealing groove is opened on the outer periphery of the plunger guide sleeve, the second O-ring slides inside the outer sealing groove, a static sealing groove is opened in the middle of the plunger guide sleeve, and the fixed sleeve is slidably connected to the inside of the static sealing groove.

[0008] Preferably, the valve core is slidably connected to the interior of the pilot valve plunger, and the main seal is interference fit with the pilot valve plunger.

[0009] Preferably, a side of the opening retaining ring close to the pilot valve plunger abuts against a side of the retaining ring away from the main seal, and a side of the opening retaining ring away from the pilot valve plunger abuts against a side of the card gasket close to the pilot valve plunger.

[0010] Preferably, a mounting plate is provided on the periphery of the plunger guide sleeve away from the pilot valve plunger, and the mounting plate is fixed to the periphery of the pilot valve body by fastening screws.

[0011] Preferably, the valve core is slidably connected to the middle part of the card gasket, and a side of the card gasket away from the metering spring abuts against an end of the pilot valve plunger close to the valve core.

[0012] The present invention provides a pilot valve plunger sealing structure, which has the following beneficial effects: 1. The pilot valve plunger is automatically reset by the reset spring of the pilot valve body. When the pilot valve plunger moves up and down, the main seal and the plunger surface slide more smoothly, reducing the possibility of leakage and being able to output the pilot fluid pressure stably.

[0013] 2. The present invention closely fits the pilot valve plunger through the main seal. The interior of the main seal is composed of a fixed sleeve, hydrogenated nitrile rubber and a self-tightening spring to form an integrated sealing component. The self-tightening spring is wrapped around the hydrogenated nitrile rubber. The spring tension makes the main seal and the pilot valve plunger fit more closely. Even if the oil temperature rises during operation, due to the effect of the self-tightening spring, the interference fit can always be maintained to prevent the occurrence of hydraulic oil leakage. Compared with traditional rubber sealing rings, the sealing is more secure and the service life is longer.

[0014] 3. The present invention provides a first O-ring inside the plunger guide sleeve and a second O-ring outside the plunger guide sleeve, which not only seals the pilot valve plunger and the pilot valve body, but also plays a positioning and guiding role, ensuring the concentricity accuracy of the pilot valve plunger and the seal, making the seal more reliable.

[0015] 4. The present invention adopts a multiple sealing design, and the structure of the sealing element has multiple oil storage ring grooves to reduce the plunger The friction force is greatly increased, which greatly improves the service life of the entire sealing structure and the performance of the pilot valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the main seal of the present invention; Figure 3 It is a structural schematic diagram of the retaining ring of the present invention; Figure 4 It is a structural schematic diagram of the plunger guide sleeve of the present invention; Figure 5 It is a structural schematic diagram of the card gasket of the present invention; Figure 6 It is a structural schematic diagram of the pilot valve plunger assembly of the present invention.

[0017] Among them, 1. pilot valve plunger; 2. first O-ring; 3. main seal; 4. second O-ring; 5. pilot valve body; 6. reset spring; 7. valve core; 8. metering spring; 9. card gasket; 10. open retaining ring; 11. retaining ring; 12. mounting plate; 13. fastening screw; 14. plunger guide sleeve; 15. fixing sleeve; 16. hydrogenated nitrile rubber; 17. self-tightening spring; 18. sealing lower lip; 19. sealing upper lip; 20. inner sealing groove; 21. outer sealing groove; 22. static sealing groove. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Please see attached Figure 1 The embodiment of the present invention provides a pilot valve plunger sealing structure, including a pilot valve body 5, a pilot valve plunger 1 sliding inside the pilot valve body 5, a plunger guide sleeve 14 sleeved on the outer periphery of the pilot valve plunger 1, a mounting plate 12 is provided on the outer periphery of the plunger guide sleeve 14 away from the pilot valve plunger 1, the mounting plate 12 is fixed to the outer periphery of the pilot valve body 5 by fastening screws 13, a main seal 3 slides inside the side of the plunger guide sleeve 14 close to the pilot valve plunger 1, a plunger hole and a sealing hole are provided inside the pilot valve body 5, a valve core 7 is installed inside the pilot valve body 5, a metering spring 8 and a reset spring 6 are sleeved on the outer periphery of the valve core 7, and an open retaining ring 10 is installed on the outer periphery of one end of the pilot valve plunger 1 close to the valve core 7.

[0020] In the present invention, a plunger hole and a sealing hole are provided inside the pilot valve body 5, and the valve core 7, the pilot valve plunger 1, the reset spring 6 and the metering spring 8 are installed to fit tightly on the card gasket 9. The pilot valve plunger 1 is pressurized to move the card gasket 9 downward, thereby driving the valve core 7 downward, the pilot valve plunger 1 is depressurized, and the reset spring 6 is automatically reset. Therefore, the valve core 7 and the metering spring 8 move up and down, which can provide a stable pressure output for the pilot valve. The sealing quality of the pilot valve plunger 1 directly affects the performance of the pilot valve. Please see attached Figure 1 - Attachment Figure 2 The main seal 3 includes a fixed sleeve 15, which is arranged inside the plunger guide sleeve 14. A hydrogenated nitrile rubber 16 is arranged on the side of the fixed sleeve 15 close to the pilot valve plunger 1. A sealing upper lip 19 and a sealing lower lip 18 are respectively arranged on the side of the hydrogenated nitrile rubber 16 close to the pilot valve plunger 1. A self-tightening spring 17 is arranged on the side of the hydrogenated nitrile rubber 16 away from the pilot valve plunger 1.

[0021] In the present invention, the main seal 3 is an integrated seal composed of a fixed sleeve 15, a hydrogenated nitrile rubber 16 and a self-tightening spring 17. The upper part of the hydrogenated nitrile rubber 16 of the seal is provided with a significantly inclined wedge-shaped sealing upper lip 19, and the sealing upper lip 19 is a convex structure. The middle section of the upper lip is provided with a friction-reducing air-avoiding ring groove, so that the pilot valve plunger 1 can move up and down more smoothly. The sealing upper lip 19 acts as a static sealing liquid, and the lower part is provided with a significantly inclined wedge-shaped sealing lower lip 18, and the sealing lower lip 18 is a convex structure. The structure is that an oil storage ring groove is arranged in the middle section of the lower lip to lubricate the dynamic seal of the pilot valve plunger 1 and reduce the friction of the joint surface. The main seal 3 is sealed with the joint surface of the plunger guide sleeve 14 and the pilot valve plunger 1 by interference fit. The self-tightening spring 17 is surrounded by a circle of hydrogenated nitrile rubber 16. The spring tension makes the main seal 3 and the pilot valve plunger 1 fit more closely. Even if the oil temperature rises during operation, the interference fit can always be guaranteed due to the action of the self-tightening spring 17 to prevent the occurrence of hydraulic oil leakage.

[0022] Please see attached Figure 1 and attached Figure 3 A retaining ring 11 is abutted against the side of the main seal 3 away from the plunger guide sleeve 14 .

[0023] In the present invention, the retaining ring 11 is a flange structure with a flange, and the flange surface is placed on the sealing hole shoulder seat provided inside the pilot valve body 5 for positioning. The inner hole of the retaining ring 11 supports the main seal 3, so that the main seal 3 fits tightly with the pilot valve plunger 1 and the plunger guide sleeve 14, thereby improving the sealing accuracy. The plunger guide sleeve 14 presses the upper surface of the retaining ring 11 flange, and the fixing sleeve 15 provided on the main seal 3 presses the upper end surface of the retaining ring 11, so that the main seal 3 is more firmly fastened and the sealing effect is better. Please see attached Figure 1 and attached Figure 4 A first O-ring 2 is provided on the side of the plunger guide sleeve 14 close to the pilot valve plunger 1, and a second O-ring 4 is provided on the side of the plunger guide sleeve 14 away from the pilot valve plunger 1. An inner sealing groove 20 is provided inside the plunger guide sleeve 14, and the first O-ring 2 slides inside the inner sealing groove 20. An outer sealing groove 21 is provided on the outer periphery of the plunger guide sleeve 14, and the second O-ring 4 slides inside the outer sealing groove 21. A static sealing groove 22 is provided in the middle of the plunger guide sleeve 14, and the fixed sleeve 15 is slidably connected inside the static sealing groove 22.

[0024] In the present invention, an inner sealing groove 20 is provided in the inner hole of the plunger guide sleeve 14, and the first O-ring 2 is installed in the groove, which is interference-fitted with the pilot valve plunger 1 to serve as a dynamic seal. An outer sealing groove 21 is provided on the outer surface of the plunger guide sleeve 14, and the second O-ring 4 is installed in the groove, which is interference-fitted with the sealing hole provided on the pilot valve body 5 to serve as a static seal. A static sealing groove 22 is provided in the middle of the plunger guide sleeve 14, and the upper part of the main seal 3 extends into the static sealing groove 22, wherein the sealing upper lip 19 is interference-fitted with the inner side of the static sealing groove 22 to serve as a static seal.

[0025] Please see attached Figure 1 and attached Figure 5 The metering spring 8 and the return spring 6 are in contact with a card gasket 9 at one end close to the pilot valve plunger 1, the valve core 7 is slidably connected to the inside of the pilot valve plunger 1, the main seal 3 is interference fit with the pilot valve plunger 1, the valve core 7 is slidably connected to the middle of the card gasket 9, and the side of the card gasket 9 away from the metering spring 8 is in contact with the end of the pilot valve plunger 1 close to the valve core 7.

[0026] In the present invention, the card gasket 9 has an upper and lower groove structure, the upper groove positions the pilot valve plunger 1, and the lower groove positions the reset spring 6 and the metering spring 8. There is a long hole in the middle of the card gasket 9, and the valve core 7 can move up and down through the hole center. The metering spring 8 pushes the valve core 7 to move and outputs a stable pilot valve liquid pressure.

[0027] Please see attached Figure 1 and attached Figure 6 The side of the open retaining ring 10 close to the pilot valve plunger 1 abuts against the side of the retaining ring 11 away from the main seal 3, and the side of the open retaining ring 10 away from the pilot valve plunger 1 abuts against the side of the card gasket 9 close to the pilot valve plunger 1.

[0028] In the present invention, the pilot valve plunger 1 is provided with a limiting groove, and the limiting groove is used to install an opening retaining ring 10 to prevent the pilot valve plunger 1 from falling out. The outer diameter of the pilot valve plunger 1 is consistent, and a high-precision sealing surface can be obtained by honing technology, thereby reducing processing costs and maximizing sealing reliability.

[0029] Working principle: After installing the main seal 3, retaining ring 11 and plunger guide sleeve 14 in the sealing hole of the pilot valve body 5, use the mounting plate 12 to press the plunger guide sleeve 14, and use the fastening screws 13 to fasten the mounting plate 12 to the pilot valve body 5, so that the inner cavity of the pilot valve body 5 forms a closed oil cavity. When the pilot valve plunger 1 moves up and down, under the action of the valve core 7, the return spring 6 and the metering spring 8, a stable pilot liquid pressure is output, thereby realizing the function of the entire pilot valve plunger sealing structure and ensuring the excellent sealing performance of the pilot valve.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pilot valve plunger sealing structure, comprising a pilot valve body (5), characterized in that: A pilot valve plunger (1) slides inside the pilot valve body (5), a plunger guide sleeve (14) is sleeved on the outer periphery of the pilot valve plunger (1), a main seal (3) slides inside the plunger guide sleeve (14) on the side close to the pilot valve plunger (1), a retaining ring (11) abuts against the side of the main seal (3) away from the plunger guide sleeve (14), a plunger hole and a sealing hole are provided inside the pilot valve body (5), a valve core (7) is installed inside the pilot valve body (5), a metering spring (8) and a return spring (6) are sleeved on the outer periphery of the valve core (7), a card gasket (9) abuts against one end of the metering spring (8) and the return spring (6) close to the pilot valve plunger (1), and an open retaining ring (10) is installed on the outer periphery of one end of the pilot valve plunger (1) close to the valve core (7).

2. A pilot valve plunger sealing structure according to claim 1, characterized in that: A first O-ring (2) is provided on a side of the plunger guide sleeve (14) close to the pilot valve plunger (1), and a second O-ring (4) is provided on an end of the plunger guide sleeve (14) away from the pilot valve plunger (1).

3. A pilot valve plunger sealing structure according to claim 2, characterized in that: The main seal (3) comprises a fixed sleeve (15), the fixed sleeve (15) being arranged inside the plunger guide sleeve (14), a hydrogenated nitrile rubber (16) being arranged on a side of the fixed sleeve (15) close to the pilot valve plunger (1), a sealing upper lip (19) and a sealing lower lip (18) being arranged on a side of the hydrogenated nitrile rubber (16) close to the pilot valve plunger (1), and a self-tightening spring (17) being arranged on a side of the hydrogenated nitrile rubber (16) away from the pilot valve plunger (1).

4. A pilot valve plunger sealing structure according to claim 3, characterized in that: An inner sealing groove (20) is provided inside the plunger guide sleeve (14), the first O-ring (2) slides inside the inner sealing groove (20), an outer sealing groove (21) is provided on the outer periphery of the plunger guide sleeve (14), the second O-ring (4) slides inside the outer sealing groove (21), a static sealing groove (22) is provided in the middle of the plunger guide sleeve (14), and the fixed sleeve (15) is slidably connected inside the static sealing groove (22).

5. A pilot valve plunger sealing structure according to claim 1, characterized in that: The valve core (7) is slidably connected to the interior of the pilot valve plunger (1), and the main sealing component (3) is interference-fitted with the pilot valve plunger (1).

6. A pilot valve plunger sealing structure according to claim 1, characterized in that: The side of the opening retaining ring (10) close to the pilot valve plunger (1) abuts against the side of the retaining ring (11) away from the main seal (3), and the side of the opening retaining ring (10) away from the pilot valve plunger (1) abuts against the side of the clamping gasket (9) close to the pilot valve plunger (1).

7. A pilot valve plunger sealing structure according to claim 1, characterized in that: A mounting plate (12) is provided on the outer periphery of the plunger guide sleeve (14) away from the pilot valve plunger (1); the mounting plate (12) is fixed to the outer periphery of the pilot valve body (5) by means of fastening screws (13).

8. A pilot valve plunger sealing structure according to claim 1, characterized in that: The valve core (7) is slidably connected to the middle part of the card gasket (9), and the side of the card gasket (9) away from the metering spring (8) abuts against the end of the pilot valve plunger (1) close to the valve core (7).

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