Overshoot pressure stop valve of closed system and using method

Abstract

The invention relates to the technical field of closed hydraulic plunger pumps, in particular to a closed system overshoot pressure stop valve which comprises a valve body, a through hole is formed in the valve body, an executing mechanism is arranged in the through hole of the valve body, an adjusting assembly is arranged at one end of the valve body, and a plug is arranged at the other end of the valve body. The executing mechanism comprises a valve sleeve, the valve sleeve is cylindrical, four annular grooves are formed in the outer side surface of the valve sleeve at intervals in the circumferential direction, an oil passing hole is formed in each annular groove, a through hole is formed in the valve sleeve in the axis direction, the diameter of the through hole in the middle of the valve sleeve is smaller than that of the through holes in the two sides, and an ejector rod is arranged in the through hole in the middle of the valve sleeve in a penetrating mode. A first valve element is arranged on the side, close to the ejector rod, in the valve sleeve, a second valve element is arranged on the other side, close to the ejector rod, in the valve sleeve, and a guide sleeve is arranged on the side, away from the ejector rod, of the first valve element. The pressure cut-off valve adopts a cone valve core shuttle valve structural design, and cut-off can be realized when any one of oil ports of the plunger pump is overpressure. The pressure stop valve is of a direct-acting structure, and secondary overshoot of pressure does not exist.

Description

Technical Field

[0001] This invention relates to the field of closed-loop hydraulic piston pump technology, and particularly to a closed-loop system overshoot pressure shut-off valve and its usage method. Background Technology

[0002] Closed-loop piston pumps, due to their high efficiency, compact design, stable and precise control, and high power density, are widely used in skid steer loaders, perfectly resolving the contradiction of achieving powerful, flexible, and precise operations in confined spaces. The application of closed-loop piston pumps in skid steer loaders is not only a technological choice but also an inevitable result of product positioning and market demand, and is one of the key technologies enabling skid steer loaders to become "all-rounders in small construction machinery."

[0003] To achieve high power density, closed-loop systems are typically designed with higher operating pressures than open-loop systems of the same specifications. To prevent the system pressure from rising indefinitely and thus protect the hydraulic pump, motor, pipelines, and seals, a high-pressure relief valve is usually installed in closed-loop piston pumps to limit the maximum system pressure and protect the hydraulic components.

[0004] Based on actual usage, it was found that even in a sliding closed system equipped with a high-pressure relief valve, components were still damaged due to high pressure. Analysis confirmed that the cause of the overpressure damage was: the valve core of the high-pressure relief valve needs a reaction time from closing to opening to overflow. During this short response time, the system pressure will continue to rise, and the pressure will momentarily exceed the limit, thus causing damage to the hydraulic components. Therefore, it is necessary to design a pressure shut-off valve to ensure the safety of the hydraulic components when the high-pressure relief valve experiences excessive pressure. Summary of the Invention

[0005] To address the above issues, a closed-loop system overshoot pressure shut-off valve and its usage method are proposed.

[0006] The technical solution of the present invention is as follows: a closed-loop system overshoot pressure shut-off valve, comprising a valve body, the valve body having a through hole, an actuator being provided within the through hole, an adjusting component being provided at one end of the valve body, and a plug being provided at the other end of the valve body; the actuator includes a valve sleeve, the valve sleeve being cylindrical, four annular grooves being spaced apart circumferentially on the outer surface of the valve sleeve, each annular groove having an oil passage hole, a through hole being provided inside the valve sleeve along the axial direction, the diameter of the through hole in the middle section of the valve sleeve being smaller than the diameter of the through holes on both sides, a push rod being inserted through the through hole in the middle section of the valve sleeve, a first valve core being provided on the side of the valve sleeve near the push rod, a second valve core being provided on the side of the valve sleeve near the push rod, and a guide sleeve being provided on the side of the first valve core away from the push rod.

[0007] Preferably, the guide sleeve has a through hole along the axial direction, and a guide sleeve step is provided on the outer circumferential direction of the guide sleeve. A step is provided in the valve body at a position corresponding to the guide sleeve step. One side of the guide sleeve step abuts against the valve sleeve, and the other side of the guide sleeve step abuts against the step in the valve body.

[0008] Preferably, the first valve core has a through hole along the axial direction, and both ends of the first valve core are tapered. When the first valve core moves along the axial direction toward the guide sleeve, the tapered part of the first valve core near the guide sleeve passes through the through hole of the guide sleeve. When the first valve core moves along the axial direction toward the push rod, the other end of the first valve core abuts against the push rod.

[0009] Preferably, the push rod is provided with a push rod step near the second valve core, and the push rod step is attached to the side wall inside the valve sleeve.

[0010] Preferably, the outer diameter of the second valve core near the push rod is smaller than the outer diameter of the section away from the push rod. One end of the second valve core abuts against the push rod, and the other end of the second valve core abuts against the adjusting assembly. An oil passage hole is provided at the end of the second valve core near the push rod.

[0011] Preferably, the adjusting assembly includes an adjusting sleeve, inside which a first support seat, an elastic element, and a second support seat are disposed. The first support seat has a first step at the end away from the second support seat, and the second support seat has a second step at the end away from the first support seat. The elastic element is sleeved on the first and second support seats, with both ends of the elastic element abutting against the opposite sides of the first and second steps. The end of the adjusting sleeve away from the actuator is connected to the outer thread of the adjusting rod via an internal thread. The side of the first support seat away from the second support seat abuts against the second valve core. The side of the second support seat away from the first support seat abuts against the adjusting rod.

[0012] Preferably, the adjusting sleeve is inserted into the valve body, and a second O-ring is fitted at the connection between the adjusting sleeve and the valve body.

[0013] Preferably, the adjusting rod is provided with a tightening member and a locking cap by threaded sleeve. The tightening member is in close contact with the outer end of the adjusting sleeve, and the locking cap is in close contact with the side of the tightening member away from the adjusting sleeve. A first O-ring is provided at the connection between the tightening member and the adjusting sleeve and at the connection between the locking cap and the tightening member.

[0014] Preferably, the plug is inserted into the valve body, and a third O-ring is provided at the connection between the plug and the valve body.

[0015] A method for using an overshoot pressure shut-off valve in a closed system, comprising the following steps: When the first oil port is the over-pressure working oil port, the second oil port is the low pressure port. Under the action of the over-pressure oil in the first oil port, the first valve core is pushed to one side of the guide sleeve. The conical surface of the first valve core and the through hole of the guide sleeve achieve a conical surface seal. The hydraulic oil reaches the pressure test port through the guide sleeve and the central through hole of the first valve core to realize the monitoring of the over-pressure. At the same time, under the action of the over-pressure oil in the first oil port, the push rod moves towards the second valve core, thereby pushing the second valve core to move against the force of the elastic element. The pilot oil trapped between the second valve core and the valve sleeve is connected to the third oil port through the oil passage and through hole of the valve sleeve, so that the pilot oil port is depressurized to zero. When the second oil port is the over-pressure working oil port, the first oil port is at low pressure. Under the action of the over-pressure oil in the second oil port, the first valve core is pushed to one side of the push rod. The hydraulic oil reaches the pressure test port through the central through hole of the guide sleeve to realize the monitoring of the over-pressure. At the same time, under the action of the over-pressure oil in the second oil port, the first valve core pushes the push rod to move towards the second valve core, thereby pushing the second valve core to move against the force of the elastic element. This allows the pilot oil trapped between the second valve core and the valve sleeve to connect with the third oil port through the oil passage and through hole of the valve sleeve, so that the pilot oil port is depressurized to zero.

[0016] The beneficial effects of this invention are as follows: Firstly, the pressure shut-off structure is ingeniously designed, with a small overall size, integrated into the pump cover, thus not increasing the design volume of the plunger pump. Secondly, the pressure shut-off valve adopts a cone valve core shuttle valve structure design, ensuring shut-off even if any port of the plunger pump experiences overpressure. Furthermore, the pressure shut-off valve uses a direct-acting structure, resulting in faster response, no secondary pressure overshoot, and high reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overshoot pressure shut-off valve structure of the closed system of the present invention; Figure 2 This is a schematic diagram of the valve sleeve structure of the present invention. Figure 3 This is a schematic diagram of the overshoot pressure shut-off valve for the closed system of the present invention.

[0018] The component names corresponding to the various reference numerals in the diagram are as follows: 1. Valve body; 2. Actuator; 21. Valve sleeve; 211. Circular groove; 212. Oil passage hole; 22. First valve core; 23. Second valve core; 231. Oil passage hole; 24. Push rod; 241. Push rod step; 25. Guide sleeve; 251. Guide sleeve step; 3. Adjusting assembly; 31. Locking cap; 32. Adjusting rod; 33. Tightening component; 34. Adjusting sleeve; 35. First support seat; 351. First step; 36. Elastic component; 37. Second support seat; 371. Second step; 38. First O-ring; 39. Second O-ring; 4. Plug; 41. Third O-ring; 5. First oil port; 6. Second oil port; 7. Pressure test port; 8. Third oil port; 9. Pilot oil port. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0020] refer to Figure 1 , 2 As shown in the figure, this application discloses a closed system overshoot pressure shut-off valve, including a valve body 1, a through hole provided in the valve body 1, an actuator 2 provided in the through hole of the valve body 1, an adjustment component 3 provided at one end of the valve body 1, and a plug 4 provided at the other end of the valve body 1.

[0021] The actuator 2 includes a valve sleeve 21, which is cylindrical. Four annular grooves 211 are spaced circumferentially on the outer surface of the valve sleeve 21. Each annular groove 211 has an oil passage hole 212. A through hole is provided inside the valve sleeve 21 along the axial direction. The diameter of the through hole in the middle section of the valve sleeve 21 is smaller than the diameter of the through holes on both sides. A push rod 24 passes through the through hole in the middle section of the valve sleeve 21. A first valve core 22 is provided on the side of the valve sleeve 21 near the push rod 24, and a second valve core 23 is provided on the other side of the valve sleeve 21 near the push rod 24. A guide sleeve 25 is provided on the side of the first valve core 22 away from the push rod 24.

[0022] The guide sleeve 25 has a through hole along the axial direction, and the outer circumferential of the guide sleeve 25 has a guide sleeve step 251. Inside the valve body 1, there is a step at a position corresponding to the guide sleeve step 251. One side of the guide sleeve step 251 abuts against the valve sleeve 21, and the other side abuts against the step inside the valve body 1, so as to limit its position.

[0023] The first valve core 22 has a through hole along the axial direction. Both ends of the first valve core 22 are tapered. When the first valve core 22 moves along the axial direction toward the guide sleeve 25, the tapered part of the first valve core 22 near the guide sleeve 25 passes through the through hole of the guide sleeve 25. The tapered surface of the first valve core 22 and the through hole of the guide sleeve 25 achieve tapered surface sealing. When the first valve core 22 moves along the axial direction toward the push rod 24, the other end of the first valve core 22 abuts against the push rod 24.

[0024] The push rod 24 is provided with a push rod step 241 near the second valve core 23. The push rod step 241 is attached to the side wall inside the valve sleeve 21, so that the push rod 24 is limited when it moves away from the second valve core 23.

[0025] The outer diameter of the section of the second valve core 23 near the push rod 24 is smaller than the outer diameter of the section away from the push rod 24. The second valve core 23 near the push rod 24 is provided with an oil passage hole 231. One end of the second valve core 23 abuts against the push rod 24, and the other end of the second valve core 23 abuts against the adjusting assembly 3. When the push rod 24 abuts against the second valve core 23 and moves it toward the adjusting assembly 3, the outer space of the section of the second valve core 23 with the smaller outer diameter and the oil passage hole are connected to the pilot oil port 9, so that the pilot oil port 9 is depressurized.

[0026] The adjusting assembly 3 includes an adjusting sleeve 34, in which a first support 35, an elastic element 36, and a second support 37 are disposed. The first support 35 has a first step 351 at the end away from the second support 37, and the second support 37 has a second step 371 at the end away from the first support 35. The elastic element 36 can be a spring. The elastic element 36 is sleeved on the first support 35 and the second support 37. The two ends of the elastic element 36 abut against the opposite side of the first step 351 and the second step 371. The end of the adjusting sleeve 34 away from the actuator 2 is connected to the outer thread of the adjusting rod 32 through an internal thread.

[0027] The first support seat 35 has a groove on the side away from the second support seat 37, and the end of the second valve core 23 away from the push rod 24 abuts in the groove of the first support seat 35; the second support seat 37 has a groove on the side away from the first support seat 35, and the adjusting rod 32 abuts in the groove of the second support seat 37.

[0028] The outer side of the adjusting sleeve 34 is threaded through the valve body 1, and a second O-ring 39 is fitted at the connection between the adjusting sleeve 34 and the valve body 1 for sealing.

[0029] The adjusting rod 32 is threaded with a tightening member 33 and a locking cap 31. The tightening member 33 is a tightening nut, and the locking cap 31 is a locking nut. The tightening member 33 is close to the outer end of the adjusting sleeve 34, and the locking cap 31 is close to the side of the tightening member 33 away from the adjusting sleeve 34. The tightening member 33 and the locking cap 31 fix the position of the adjusting rod 32 after the elastic force of the elastic member 36 is adjusted.

[0030] A first O-ring 38 is provided at the connection between the clamping member 33 and the adjusting sleeve 34, and at the connection between the locking cap 31 and the clamping member 33, for sealing purposes.

[0031] The plug 4 is threaded through the valve body 1, and a third O-ring 41 is provided at the connection between the plug 4 and the valve body 1 for sealing.

[0032] refer to Figure 1 , 3 As shown, a method for using an overshoot pressure shut-off valve in a closed system includes the following steps: When the first oil port 5 is the over-pressure working oil port, the second oil port 6 is the low pressure port. Under the action of the over-pressure oil at the first oil port 5, the first valve core 22 is pushed to one side of the guide sleeve 25. The conical surface of the first valve core 22 and the through hole of the guide sleeve 25 achieve a conical surface seal. The hydraulic oil reaches the pressure measuring port 7 through the central through hole of the guide sleeve 25 and the first valve core 22 to monitor the over-pressure. At the same time, under the action of the over-pressure oil at the first oil port 5, the push rod 24 moves towards the second valve core 23, thereby pushing the second valve core 23 to move against the force of the elastic element 36. This allows the pilot oil of the pilot oil port 9, which is trapped between the second valve core 23 and the valve sleeve 21, to connect with the third oil port 8 through the oil passage 212 and the oil passage 231 of the valve sleeve, so that the pilot oil port 9 is depressurized to zero.

[0033] When the second oil port 6 is the over-pressure working oil port, the first oil port 5 is at low pressure. Under the action of the over-pressure oil in the second oil port 6, the first valve core 22 is pushed to one side of the push rod 24. The hydraulic oil reaches the pressure measuring port 7 through the central through hole of the guide sleeve 25 to realize the monitoring of the over-pressure. At the same time, under the action of the over-pressure oil in the second oil port 6, the first valve core 22 pushes the push rod 24 to move towards the second valve core 23, thereby pushing the second valve core 23 to move against the force of the elastic element 36. This allows the pilot oil in the pilot oil port 9, which is trapped between the second valve core 23 and the valve sleeve 21, to connect with the third oil port 8 through the oil passage hole 212 and the oil passage hole 231 of the valve sleeve, so that the pilot oil port 9 is depressurized to zero.

[0034] The beneficial effects are: This invention features a cleverly designed pressure shut-off structure with a small overall size, integrated into the pump cover without increasing the design volume of the plunger pump. Secondly, the pressure shut-off valve employs a cone valve core shuttle valve structure design, ensuring shut-off even in the event of overpressure at any port of the plunger pump. Furthermore, the pressure shut-off valve utilizes a direct-acting structure, resulting in faster response, eliminating secondary pressure overshoot, and ensuring high reliability.

[0035] It should be noted that the terms "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present 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, and therefore should not be construed as a limitation of the present invention. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. "A plurality of" means two or more. "Installed," "connected," and "joined" should be interpreted broadly; for example, it can refer to a fixed connection, a detachable connection, or an integral connection.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A closed-loop system overshoot pressure shut-off valve, characterized in that, The valve body (1) includes a valve body (1) with a through hole. An actuator (2) is provided inside the through hole of the valve body (1). An adjusting component (3) is provided at one end of the valve body (1), and a plug (4) is provided at the other end of the valve body (1). The actuator (2) includes a valve sleeve (21), which is cylindrical. Four annular grooves (211) are opened circumferentially on the outer surface of the valve sleeve (21). Each annular groove (211) is provided with an oil passage hole (212). 21) An internal through hole is provided along the axial direction. The diameter of the through hole in the middle section of the valve sleeve (21) is smaller than the diameter of the through holes on both sides. A push rod (24) is inserted through the through hole in the middle section of the valve sleeve (21). A first valve core (22) is provided on the side of the valve sleeve (21) close to the push rod (24). A second valve core (23) is provided on the other side of the valve sleeve (21) close to the push rod (24). A guide sleeve (25) is provided on the side of the first valve core (22) away from the push rod (24).

2. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The guide sleeve (25) has a through hole along the axial direction. The outer circumferential direction of the guide sleeve (25) has a guide sleeve step (251). A step is provided in the valve body (1) at the corresponding position of the guide sleeve step (251). One side of the guide sleeve step (251) abuts against the valve sleeve (21), and the other side of the guide sleeve step (251) abuts against the step in the valve body (1).

3. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The first valve core (22) has a through hole along the axial direction. Both ends of the first valve core (22) are tapered. When the first valve core (22) moves along the axial direction to the guide sleeve (25), the tapered part of the first valve core (22) near the guide sleeve (25) passes through the through hole of the guide sleeve (25). When the first valve core (22) moves along the axial direction to the push rod (24), the other end of the first valve core (22) abuts against the push rod (24).

4. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The push rod (24) is provided with a push rod step (241) near the second valve core (23), and the push rod step (241) is attached to the side wall inside the valve sleeve (21).

5. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The outer diameter of the second valve core (23) near the top rod (24) is smaller than the outer diameter of the section away from the top rod (24). One end of the second valve core (23) rests against the top rod (24), and the other end of the second valve core (23) rests against the adjusting assembly (3). The end of the second valve core (23) near the top rod (24) is provided with an oil passage hole (231).

6. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The adjustment assembly (3) includes an adjustment sleeve (34), in which a first support seat (35), an elastic element (36), and a second support seat (37) are provided. The first support seat (35) has a first step (351) at the end away from the second support seat (37), and the second support seat (37) has a second step (371) at the end away from the first support seat (35). The elastic element (36) is sleeved on the first support seat (35) and the second support seat (37). The two ends of the elastic element (36) abut against the opposite side of the first step (351) and the second step (371). The end of the adjustment sleeve (34) away from the actuator (2) is connected to the outer thread of the adjustment rod (32) through an internal thread. The side of the first support seat (35) away from the second support seat (37) abuts against the second valve core (23). The side of the second support seat (37) away from the first support seat (35) abuts against the adjustment rod (32).

7. The overshoot pressure shut-off valve for a closed system according to claim 6, characterized in that, The adjusting sleeve (34) is inserted inside the valve body (1), and a second O-ring (39) is fitted at the connection between the adjusting sleeve (34) and the valve body (1).

8. The overshoot pressure shut-off valve for a closed system according to claim 6, characterized in that, The adjusting rod (32) is threaded with a tightening member (33) and a locking cap (31). The tightening member (33) is in close contact with the outer port of the adjusting sleeve (34), and the locking cap (31) is in close contact with the side of the tightening member (33) away from the adjusting sleeve (34). A first O-ring (38) is provided at the connection between the tightening member (33) and the adjusting sleeve (34) and at the connection between the locking cap (31) and the tightening member (33).

9. The overshoot pressure shut-off valve for a closed system according to claim 1, characterized in that, The plug (4) is inserted inside the valve body (1), and a third O-ring (41) is provided at the connection between the plug (4) and the valve body (1).

10. A method of using an overshoot pressure shut-off valve in a closed system as described in any one of claims 1-9, characterized in that, The steps are as follows: When the first oil port (5) is the over-pressure working oil port, the second oil port (6) is the low pressure port. Under the action of the over-pressure oil at the first oil port (5), the first valve core (22) is pushed to one side of the guide sleeve (25). The conical surface of the first valve core (22) and the through hole of the guide sleeve (25) achieve a conical surface seal. The hydraulic oil reaches the pressure measuring port (7) through the central through hole of the guide sleeve (25) and the first valve core (22), thus realizing the over-pressure... The monitoring; at the same time, under the action of the over-adjustment pressure oil of the first oil port (5), the push rod (24) moves towards the second valve core (23), thereby pushing the second valve core (23) to move against the force of the elastic element (36), so that the pilot oil of the pilot oil port (9) trapped between the second valve core (23) and the valve sleeve (21) is connected to the third oil port (8) through the oil passage hole (212) and the oil passage hole (231) of the valve sleeve, so that the pilot oil port (9) is depressurized to zero; When the second oil port (6) is the over-pressure working oil port, the first oil port (5) is low pressure. Under the action of the over-pressure oil in the second oil port (6), the first valve core (22) is pushed to one side of the push rod (24). The hydraulic oil reaches the pressure measuring port (7) through the central through hole of the guide sleeve (25) to realize the monitoring of the over-pressure. At the same time, under the action of the over-pressure oil in the second oil port (6), the first valve core (22) pushes the push rod (24) to move towards the second valve core (23), thereby pushing the second valve core (23) to move against the force of the elastic element (36). The pilot oil of the pilot oil port (9) trapped between the second valve core (23) and the valve sleeve (21) is connected to the third oil port (8) through the oil passage (212) and the oil passage (231) of the valve sleeve, so that the pilot oil port (9) is depressurized to zero.

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