Pneumatic pull rod reversing valve with emergency function

Abstract

The utility model discloses a pneumatic pull rod reversing valve with an emergency function, and relates to the technical field of hydraulic system oil way control elements. The valve comprises a valve body arranged in the front-back direction. A valve rod is slidably connected into the valve body. The rear end of the valve rod is fixedly sleeved with an air piston; a positioning cavity, an oil return cavity, a high-pressure cavity, a lifting cavity and a reversing air cavity are sequentially formed in the valve body from front to back. A reset spring used for pushing the valve rod forwards to reset is arranged in the positioning cavity. The lower part of the oil return cavity is communicated with that of the high-pressure cavity; an overflow valve is fixed outside the valve body; the upper end of the high-pressure cavity is connected with the overflow valve; an oil inlet is fixed outside the valve body; the oil inlet is connected with the high-pressure cavity through an oil inlet one-way valve. The hydraulic reversing valve has the advantages that the problems that due to excessive hydraulic oil impurities, a valve element of an existing reversing valve is clamped, maintenance and replacement are inconvenient, and the service cost is high are solved, and meanwhile the production difficulty that the concentricity is high when the valve body and the valve element are machined is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic system oil circuit control elements, in particular to a pneumatic pull-rod reversing valve with an emergency function. Background Art

[0002] The conventional function of the pneumatic pull-rod reversing valve is a reversing switch used to change the direction of the liquid flow in the hydraulic lifting system of a dump truck. This switch is used in conjunction with a hydraulic pump, a control air valve, and a limit air valve to form a dump truck hydraulic system to achieve lifting, lowering, and intermediate stops.

[0003] The existing pneumatic control reversing valve main components are mostly assembled by connecting the valve body, cylinder and valve core, and fixed with bolts. This structural form has two main defects in use and assembly.

[0004] The defect of use is: after the dump truck has been used for a period of time, if it is not maintained regularly and the air filter and hydraulic oil are not replaced in time, it will cause excessive impurities in the hydraulic oil, causing the valve core of the reversing valve to get stuck. For example, if it gets stuck after lifting the cargo box, the large box will not fall. In order to ensure safety, the maintenance master will generally use a crane or a traveling crane to temporarily fix the cargo box according to the environment where the dump truck is located, and then clean or replace the hydraulic reversing valve for maintenance. The cost of replacement parts and related service costs will be very high.

[0005] The assembly defect is that the concentricity of the connection between the valve body and the valve core requires extremely high processing precision. When the concentricity of the positioning step connecting the valve body and the valve core is low, the valve core will be stuck and unable to achieve reversal, resulting in a low one-time pass rate for the installed finished product. Utility Model Content

[0006] The technical problem to be solved by the present invention is to provide a pneumatic pull-rod reversing valve with an emergency function in response to the above-mentioned technical deficiencies. The pneumatic pull-rod reversing valve solves the problems of the existing reversing valve in which the valve core is stuck due to excessive impurities in the hydraulic oil, which makes maintenance and replacement inconvenient and the service cost high. At the same time, the pneumatic pull-rod reversing valve solves the production difficulty of requiring high concentricity when processing the valve body and the valve core.

[0007] The technical solution adopted by the utility model is to provide a pneumatic pull-rod reversing valve with an emergency function, comprising a valve body arranged along the front-back direction; a valve stem is slidably connected to the inside of the valve body; a gas piston is sleeved and fixed on the rear end of the valve stem;

[0008] The interior of the valve body is provided with a positioning chamber, an oil return chamber, a high-pressure chamber, a lifting chamber and a reversing air chamber in sequence from front to back; a return spring is provided inside the positioning chamber for pushing the valve stem forward and returning it to its original position; the lower part of the oil return chamber is connected to the lower part of the high-pressure chamber; a relief valve is fixed to the outside of the valve body; the upper end of the high-pressure chamber is connected to the relief valve; an oil inlet is fixed to the outside of the valve body; the oil inlet is connected to the high-pressure chamber through an oil inlet check valve; the lower part of the high-pressure chamber is connected to the upper part of the lifting chamber; the lower part of the lifting chamber is connected to the lifting port; the rear end of the reversing air chamber is sealed and fixed with a cylinder head; the air piston is slidingly and sealingly connected in the reversing air chamber; the upper side of the front end of the reversing air chamber is connected to the lifting port, and the upper side of the rear end is connected to the descending port;

[0009] The valve stem is integrally formed with three sections of valve cores coaxially distributed in the front, middle and rear sections; the valve core of the front section blocks the positioning chamber and the return oil chamber; the valve core at the rear end blocks the lifting chamber and the reversing air chamber; the valve core in the middle section is used to switch the connection state between the high-pressure chamber and the lifting chamber; when the valve stem slides backward inside the valve body, the valve core in the front section blocks the return oil chamber and the high-pressure chamber, and the valve core in the middle section releases the blockage between the high-pressure chamber and the lifting chamber; when the valve stem slides forward inside the valve body, the valve core in the front section releases the blockage between the return oil chamber and the high-pressure chamber, and the valve core in the middle section blocks the high-pressure chamber and the lifting chamber; the front end of the valve stem extends out of the valve body and is provided with an emergency hole.

[0010] To further optimize this technical solution, the front end of the positioning cavity of the pneumatic pull-rod reversing valve with an emergency function is sleeved and fixed with a hole retaining ring; the front part of the valve stem is sleeved and fixed with a shaft retaining ring; the hole retaining ring is used to block the shaft retaining ring; the valve stem is slidingly sleeved with a spring washer and a spring sleeve; the return spring is sleeved on the valve stem; the front and rear ends of the return spring are respectively blocked by the spring washer and the spring sleeve; the front end of the spring washer is blocked by the shaft retaining ring; and the rear end of the spring sleeve is blocked by the rear end of the positioning cavity.

[0011] To further optimize this technical solution, the front end of the valve body of the pneumatic pull-rod reversing valve with an emergency function is detachably connected to a dust cap; the dust cap is covered on the outside of the front end of the valve stem.

[0012] The beneficial effects of the present invention are:

[0013] High-pressure air can be injected through the lifting air port to push the air piston backward in the reversing air chamber, thereby driving the valve stem to move backward, thereby realizing the lifting action; the high-pressure hydraulic oil in the high-pressure chamber can enter the lifting chamber, and the pressure provided by the hydraulic oil to the middle section of the valve core can achieve locking of the lifting state, thereby ensuring full support for the cargo box.

[0014] High-pressure air can be injected through the descending air port to push the air piston forward in the reversing air chamber, driving the valve stem forward, that is, realizing the descending action; the hydraulic oil in the high-pressure chamber can flow back to the return oil chamber, and the descending state can be locked with the help of the pressure of the hydraulic oil; the overflow valve plays a safety protection role, which can discharge the excess hydraulic oil in the high-pressure chamber to prevent the system pressure from being too high and affecting the lifting and lowering action of the valve stem; the elastic force of the reset spring helps to push the valve stem forward and reset it to the descending end position.

[0015] The front end of the valve stem extends out of the valve body and is provided with an emergency hole. The valve stem can be urgently lowered by pulling the emergency hole, solving the problem of the lifted cargo box getting stuck, making maintenance convenient and saving costs. The valve core and valve stem are integrally formed to avoid the difficulty of combined installation requiring high concentricity of the valve body and valve core, and avoid the problem of low one-time pass rate of the installed finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the local structure at the front end of the valve stem;

[0018] Figure 3 It is a schematic diagram of the overall appearance structure of the utility model.

[0019] In the figure, 1. valve body; 2. valve stem; 3. air piston; 4. positioning chamber; 5. oil return chamber; 6. high-pressure chamber; 7. lifting chamber; 8. reversing air chamber; 9. return spring; 10. relief valve; 11. oil inlet; 12. oil inlet check valve; 13. lifting port; 14. cylinder head; 15. lifting port; 16. descending port; 17. valve core; 18. emergency hole; 19. retaining ring for hole; 20. retaining ring for shaft; 21. spring washer; 22. spring sleeve; 23. dust cap. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0021] like Figure 1 As shown, the pneumatic pull-rod reversing valve with emergency function includes a valve body 1 arranged along the front-back direction; a valve stem 2 is slidably connected to the inside of the valve body 1; and a gas piston 3 is sleeved and fixed to the rear end of the valve stem 2;

[0022] like Figure 1-3As shown, the interior of the valve body 1 is provided with a positioning chamber 4, an oil return chamber 5, a high-pressure chamber 6, a lifting chamber 7 and a reversing air chamber 8 in sequence from front to back; a return spring 9 is provided inside the positioning chamber 4 for pushing the valve stem 2 forward and resetting; the lower part of the oil return chamber 5 is connected to the lower part of the high-pressure chamber 6; an overflow valve 10 is fixed to the outside of the valve body 1; the upper end of the high-pressure chamber 6 is connected to the overflow valve 10; an oil inlet 11 is fixed to the outside of the valve body 1; the oil inlet 11 is connected to the high-pressure chamber 6 through an oil inlet check valve 12; the lower part of the high-pressure chamber 6 is connected to the upper part of the lifting chamber 7; the lower part of the lifting chamber 7 is connected to the lifting port 13; the rear end of the reversing air chamber 8 is sealed and fixed with a cylinder head 14; the gas piston 3 is slidingly and sealingly connected in the reversing air chamber 8; the upper side of the front end of the reversing air chamber 8 is connected to the lifting air port 15, and the upper side of the rear end is connected to the descending air port 16;

[0023] like Figure 1-2 As shown, the valve stem 2 is integrally formed with three sections of valve cores 17 coaxially distributed in the front, middle and rear sections; the valve core 17 of the front section blocks the positioning chamber 4 and the return oil chamber 5; the valve core 17 at the rear end blocks the lifting chamber 7 and the reversing air chamber 8; the valve core 17 in the middle section is used to switch the communication state between the high-pressure chamber 6 and the lifting chamber 7; when the valve stem 2 slides backward inside the valve body 1, the valve core 17 of the front section blocks the return oil chamber 5 and the high-pressure chamber 6, and the valve core 17 in the middle section releases the blockage between the high-pressure chamber 6 and the lifting chamber 7; when the valve stem 2 slides forward inside the valve body 1, the valve core 17 of the front section releases the blockage between the return oil chamber 5 and the high-pressure chamber 6, and the valve core 17 in the middle section blocks the high-pressure chamber 6 and the lifting chamber 7; the front end of the valve stem 2 extends out of the valve body 1 and is provided with an emergency hole 18.

[0024] In this technical solution, the rearward movement of the valve stem 2 represents a lifting action on the cargo box, while the forward movement represents a lowering action.

[0025] During the lifting action, high-pressure gas enters the front side of the reversing air chamber 8 through the lifting air port 15, pushing the air piston 3 to move backward, and the descending air port 16 is exhausted at this time, thereby driving the valve stem 2 to lift the cargo box, and at this time, through the movement of the valve core 17, the high-pressure chamber 6 is connected with the lifting chamber 7, and the high-pressure chamber 6 is blocked from the oil return chamber 5. The hydraulic oil entering the high-pressure chamber 6 through the oil inlet 11 and the oil inlet one-way valve 12 can enter the lifting chamber 7, exerting sufficient pressure on the corresponding valve core 17, so that the lifting state can be locked at any time, ensuring sufficient supporting force for the cargo box.

[0026] During the descent, high-pressure gas flows from the descent port 16 into the reversing chamber 8, pushing the gas piston 3 forward. The lift port 15 then vents, driving the valve stem 2 forward and lowering the cargo box. Simultaneously, the movement of the valve core 17 connects the return chamber 5 with the high-pressure chamber 6, blocking the high-pressure chamber 6 from the lift chamber 7. This locks the descent state through the hydraulic oil pressure. The lift port 13 drains excess hydraulic oil to prevent pressure instability.

[0027] The relief valve 10 serves as a safety protection and can discharge excess hydraulic oil in the high-pressure chamber 6 to prevent the system pressure from being too high and affecting the lifting and lowering action of the valve stem 2.

[0028] Under normal working conditions, the valve stem 2 can descend smoothly, and the pressure of the return spring 9 can also help to reset the valve stem 2 to the position of the descent end point. However, if the valve stem 2 and the valve core 17 of the reversing valve are stuck due to excessive impurities in the hydraulic oil, it will not be able to descend smoothly. The traditional method requires the use of external lifting equipment to fix the cargo box first, and then carry out maintenance, which is costly, time-consuming and labor-intensive. In this technical solution, since the valve stem 2 extends all the way to the outside of the valve body 1 and an emergency hole 18 is provided, it is possible to easily apply external force through the emergency hole 18 to pull the valve stem 2 urgently to make the valve stem 2 descend. After that, maintenance is very convenient, saving time and cost.

[0029] In addition, during assembly, the valve stem 2 and the valve core 17 in the present technical solution are processed in an integral manner, which will not cause the valve core 17 to get stuck easily due to errors in traditional assembly installation. It also avoids the difficulty of processing the high concentricity requirements of the valve body 1 and the valve core 17 during combined assembly and installation, as well as the problem of low one-time pass rate of the installed finished product.

[0030] like Figure 1-2 As shown, the front end of the positioning cavity 4 is sleeved and fixed with a hole retaining ring 19; the front part of the valve stem 2 is sleeved and fixed with a shaft retaining ring 20; the hole retaining ring 19 is used to block the shaft retaining ring 20; the valve stem 2 is slidably sleeved with a spring washer 21 and a spring sleeve 22; the return spring 9 is sleeved on the valve stem 2; the front and rear ends of the return spring 9 are respectively blocked by the spring washer 21 and the spring sleeve 22; the front end of the spring washer 21 is blocked by the shaft retaining ring 20; the rear end of the spring sleeve 22 is blocked by the rear end of the positioning cavity 4.

[0031] When the valve stem 2 moves backward and is lifted, the shaft retaining ring 20 pushes the spring washer 21 to move backward. Since the spring sleeve 22 is blocked by the positioning cavity 4, the return spring 9 is compressed at this time; when the valve stem 2 moves forward and descends, the valve stem 2 drives the shaft retaining ring 20 to move forward, and the deformation of the return spring 9 begins to recover, generating thrust to help the valve stem 2 move forward until the shaft retaining ring 20 is blocked by the hole retaining ring 19 again, and the valve stem 2 descends to the end point.

[0032] like Figure 1-3As shown, a dust cap 23 is detachably connected to the front end of the valve body 1; the dust cap 23 covers the exterior of the front end of the valve stem 2. The dust cap 23 shields and protects the exposed portion of the front end of the valve stem 2, preventing foreign matter from entering the valve body 1 through the valve stem 2, thereby improving the reliability of the reversing valve. The dust cap 23 can be connected to the valve body 1 using a threaded or snap-fit ​​connection, allowing for quick and easy removal. When the valve stem 2 needs to be urgently pulled through the emergency hole 18, the dust cap 23 can be quickly removed.

[0033] It is understood that the present invention is described by way of certain embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the guidance of the present invention, these features and embodiments may be modified to suit specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A pneumatic pull-rod reversing valve with emergency function, characterized by: It comprises a valve body (1) arranged in the front-back direction; a valve stem (2) is slidably connected inside the valve body (1); a gas piston (3) is sleeved and fixed at the rear end of the valve stem (2); The valve body (1) is provided with a positioning chamber (4), an oil return chamber (5), a high pressure chamber (6), a lifting chamber (7) and a reversing air chamber (8) in sequence from front to back; a return spring (9) is provided inside the positioning chamber (4) for pushing the valve stem (2) forward and returning it to its original position; the lower part of the oil return chamber (5) is connected to the lower part of the high pressure chamber (6); an overflow valve (10) is fixed to the outside of the valve body (1); the upper end of the high pressure chamber (6) is connected to the overflow valve (10); an oil inlet is fixed to the outside of the valve body (1) (11); the oil inlet (11) is connected to the high-pressure chamber (6) through an oil inlet check valve (12); the lower part of the high-pressure chamber (6) is connected to the upper part of the lifting chamber (7); the lower part of the lifting chamber (7) is connected to the lifting port (13); the rear end of the reversing air chamber (8) is sealed and fixed with a cylinder head (14); the gas piston (3) is slidingly sealed and connected in the reversing air chamber (8); the upper side of the front end of the reversing air chamber (8) is connected to the lifting port (15), and the upper side of the rear end is connected to the descending port (16); The valve stem (2) is integrally formed with three sections of valve cores (17) coaxially distributed in front, middle and back. The valve core (17) in the front section blocks the positioning chamber (4) and the oil return chamber (5); the valve core (17) in the rear section blocks the lifting chamber (7) and the reversing air chamber (8); the valve core (17) in the middle section is used to switch the communication state between the high-pressure chamber (6) and the lifting chamber (7); when the valve stem (2) slides and moves backward inside the valve body (1), the valve core (17) in the front section blocks the oil return chamber ( The valve stem (2) is connected to the oil return chamber (5) and the high pressure chamber (6), and the valve core (17) in the middle section releases the blockage between the high pressure chamber (6) and the lifting chamber (7); when the valve stem (2) slides forward inside the valve body (1), the valve core (17) in the front section releases the blockage between the oil return chamber (5) and the high pressure chamber (6), and the valve core (17) in the middle section blocks the high pressure chamber (6) and the lifting chamber (7); the front end of the valve stem (2) extends out from the valve body (1) and is provided with an emergency hole (18).

2. The pneumatic pull-rod reversing valve with emergency function according to claim 1, characterized in that: A hole retaining ring (19) is sleeved and fixed on the front end of the positioning cavity (4); a shaft retaining ring (20) is sleeved and fixed on the front end of the valve stem (2); the hole retaining ring (19) is used to block the shaft retaining ring (20); a spring washer (21) and a spring sleeve (22) are slidably sleeved on the valve stem (2); a return spring (9) is sleeved on the valve stem (2); the front and rear ends of the return spring (9) are respectively blocked by the spring washer (21) and the spring sleeve (22); the front end of the spring washer (21) is blocked by the shaft retaining ring (20); and the rear end of the spring sleeve (22) is blocked by the rear end of the positioning cavity (4).

3. The pneumatic pull-rod reversing valve with emergency function according to claim 1, characterized in that: The front end of the valve body (1) is detachably connected to a dust cap (23); the dust cap (23) covers the outside of the front end of the valve stem (2).

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