Speed limiting valve special for forklift

Abstract

The speed limiting valve special for the forklift comprises a valve body and a valve cover, an oil inlet is formed in the surface of the valve body, an oil outlet is formed in the surface of the valve cover, an assembly structure is arranged between the valve body and the valve cover, a valve element structure is arranged in the valve body, and an oil resistance adjusting structure is arranged on the right side of the valve element structure. By arranging the valve element structure and the oil resistance adjusting structure, when the adjusting screw rod is rotated, the position of the piston can be changed, so that the contraction strength of the compression spring can be controlled by utilizing the piston to be close to or far away from the conical valve element, and compared with the prior art, the device can drive the piston to be far away from the conical valve element when valuables fall under light load; therefore, the elastic force of the compression spring can be reduced, hydraulic oil can be forced to push the conical valve element to be close to the conical ring with small power, the descending speed of the pallet fork can be reduced when the pallet fork is in light load, and precious goods are prevented from being damaged due to the fact that the descending speed of the pallet fork is too high.

Description

Technical Field

[0001] The utility model relates to the technical field of valves, in particular to a speed limiting valve for forklifts. Background Art

[0002] The speed limiting valve for forklifts disclosed in the publication number CN 206377087U includes a valve housing and a joint that are adapted to each other. An external oil port Z is provided on the valve housing, and an external oil port P is provided on the joint. A valve core assembly is assembled in the valve housing. The valve core assembly includes a speed limiting valve body, a speed limiting valve core, an adjusting rod, a throttle valve core, a spring seat, and a speed limiting spring. The speed limiting valve core is axially slidably assembled in the speed limiting valve body. One end of the adjusting rod is fixed to the end face of the speed limiting valve core, and a spring seat is assembled at the other end of the adjusting rod. The speed limiting spring is assembled between the spring seat and the speed limiting valve body. The throttle valve core is axially slidably sleeved on the adjusting rod. The advantages of the utility model are as follows: the structure is simple, and the pressure loss in the P to Z direction is small; the speed limiting flow rate difference in the Z to P direction is small and stable under different loads, and the current limiting response speed is fast, and it can also perform well under extreme working conditions.

[0003] However, the device has the following defects when in use: the device uses the flow resistance generated by the self-weight of the forklift load driving the hydraulic oil to flow and the spring force to balance each other to adjust the flow rate. Although the flow rate of the oil can be adjusted, the flow rate of the speed limiting valve cannot be adjusted according to different working conditions. Especially when a valuable item is dropped under a light load, the falling speed of the forklift fork cannot be flexibly changed. For this reason, we propose a speed limiting valve for forklifts. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a speed limiting valve for forklifts to solve the problems raised in the above background art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A speed limiting valve for forklifts includes a valve body and a valve cover. An oil inlet is provided on the surface of the valve body, an oil outlet is provided on the surface of the valve cover, an assembly structure is provided between the valve body and the valve cover, a valve core structure is provided inside the valve body, and an oil resistance adjusting structure is provided on the right side of the valve core structure;

[0007] The valve core structure includes a conical ring fixedly installed on the inner ring surface of the valve body, and a conical valve core slidably installed on the inner wall of the conical ring. A drain hole is provided at the central position of the conical valve core;

[0008] The oil resistance adjusting structure includes a piston slidably installed on the inner wall of the valve body, and an adjusting screw rod slidably connected to the right end of the valve body through a sealing ring. The left end of the adjusting screw rod extends into the interior of the valve body and is rotatably connected to the right end of the piston. A plurality of oil delivery holes are provided on the surface of the piston in a circumferential array.

[0009] Preferably, the piston is located on the right side of the conical valve core. The right end of the adjusting screw extends to the outside of the valve body and is threadedly connected with a locking nut, and the left end of the locking nut is fixedly connected to the right end of the valve body.

[0010] Preferably, the assembly structure includes an external thread provided on the outer circumferential surface of the valve body and an internal thread provided on the inner circumferential surface of the valve cover, and a sealing ring is provided inside the valve cover.

[0011] Preferably, a through hole communicating with the oil discharge hole is provided at the right end of the conical valve core. A compression spring is provided on the inner wall of the through hole, and one end of the compression spring away from the conical valve core abuts against the left end of the piston.

[0012] Preferably, the oil inlet communicates with the inside of the valve body, and the oil outlet communicates with the inside of the valve cover.

[0013] Preferably, a plurality of baffles for restricting excessive movement of the conical valve core are arranged in a circumferential array at the right end of the conical valve core.

[0014] The utility model has the following advantages compared with the prior art:

[0015] 1. By setting the valve core structure and the oil resistance adjustment structure in the utility model, when the forklift fork load drops due to its own weight, at this time, the hydraulic oil will enter the valve cover along the oil discharge port. The hydraulic oil in the valve cover will push the conical valve core to move to the right against the elastic force of the compression spring. When the conical valve core gradually moves to the right, the conical valve core will largely block the gap between the conical valve core and the conical ring, thereby reducing the flow rate and slowing down the descending speed of the forklift fork. When the adjusting screw is rotated, the position of the piston can be changed, so that the piston can be used to approach or move away from the conical valve core to control the contraction strength of the compression spring. Compared with the prior art, when the device drops precious items under light load, the piston can be driven to move away from the conical valve core, thereby reducing the elastic force of the compression spring, forcing the hydraulic oil to require very little power to push the conical valve core close to the conical ring, so that the descending speed of the forklift fork can be slowed down under light load of the forklift fork, avoiding damage to the goods caused by too fast descending speed.

[0016] 2. By setting the oil discharge hole in the utility model, when the load on the forklift fork is too large, the conical valve core will completely block the conical ring. At this time, the hydraulic oil will slowly flow into the valve body along the oil discharge hole, avoiding the problem that the hydraulic oil cannot flow through and the forklift fork cannot descend due to too large a load on the forklift fork. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The three-dimensional structure diagram proposed by the utility model;

[0018] Figure 2 The front sectional structure diagram proposed by the utility model;

[0019] Figure 3 Schematic three-dimensional structure diagram of the valve body proposed for the utility model;

[0020] Figure 4 Schematic front sectional structure diagram of the valve body proposed for the utility model;

[0021] Figure 5 Schematic front sectional structure diagram of the valve cover proposed for the utility model;

[0022] Figure 6 Schematic side sectional structure diagram of the valve body proposed for the utility model.

[0023] In the figure: 1 valve body, 2 valve cover, 3 oil inlet, 4 oil drain port, 5 conical ring, 6 conical valve core, 7 oil drain hole, 8 piston, 9 adjusting screw, 10 oil delivery hole, 11 locking nut, 12 external thread, 13 internal thread, 14 sealing ring, 15 compression spring, 16 baffle, 17 sealing ring. Specific embodiments

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments.

[0025] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0026] Refer to Figure 1-6 , a special speed limit valve for forklifts, including a valve body 1 and a valve cover 2. An oil inlet 3 is provided on the surface of the valve body 1, and an oil drain port 4 is provided on the surface of the valve cover 2. The oil inlet 3 is communicated with the inside of the valve body 1, and the oil drain port 4 is communicated with the inside of the valve cover 2. And an assembly structure is provided between the valve body 1 and the valve cover 2. The assembly structure includes an external thread 12 opened on the outer ring surface of the valve body 1 and an internal thread 13 opened on the inner ring surface of the valve cover 2. And a sealing ring 14 is provided inside the valve cover 2. The external thread 12 on the valve body 1 is threadedly connected with the internal thread 13 inside the valve cover 2, so that the valve body 1 and the valve cover 2 can be assembled into one body. At this time, the sealing ring 14 will seal the connection between the valve body 1 and the valve cover 2.

[0027] Inside the valve body 1, a spool structure is provided. The spool structure includes a conical ring 5 fixedly installed on the inner ring surface of the valve body 1, and a conical spool 6 slidably installed on the inner wall of the conical ring 5. An oil drain hole 7 is opened at the central position of the conical spool 6. At the right end of the conical spool 6, a plurality of baffles 16 for restricting the excessive movement of the conical spool 6 are arranged in a circumferential array. When the conical spool 6 moves to the left, the gap between the conical ring 5 and the conical spool 6 becomes larger at this time, so as to increase the flow rate of the hydraulic oil. And when the conical spool 6 moves excessively to the left, the baffle 16 will contact the right side of the conical ring 5 at this time, so as to restrict the conical spool 6 from continuing to move to the left.

[0028] On the right side of the spool structure, an oil resistance adjusting structure is provided. The oil resistance adjusting structure includes a piston 8 slidably installed on the inner wall of the valve body 1, and an adjusting screw 9 slidably connected to the right end of the valve body 1 through a sealing ring 17. The left end of the adjusting screw 9 extends into the interior of the valve body 1 and is rotatably connected to the right end of the piston 8. A plurality of oil delivery holes 10 are arranged in a circumferential array on the surface of the piston 8. The piston 8 is located on the right side of the conical spool 6. The right end of the adjusting screw 9 extends to the outside of the valve body 1 and is threadedly connected with a locking nut 11, and the left end of the locking nut 11 is fixedly connected to the right end of the valve body 1. When the hydraulic oil enters the valve body 1 from the oil inlet 3, the hydraulic oil will push the conical spool 6 to move to the left. The hydraulic oil will enter the valve cover 2 along the oil delivery holes 10, the conical ring 5 and the oil drain hole 7, and be discharged along the oil drain port 4.

[0029] A through hole communicating with the oil drain hole 7 is opened at the right end of the conical spool 6. A compression spring 15 is arranged on the inner wall of the through hole. The end of the compression spring 15 away from the conical spool 6 abuts against the left end of the piston 8. When the forklift fork descends under the load of its own weight, the hydraulic oil will enter the valve cover 2 along the oil drain port 4 at this time. The hydraulic oil in the valve cover 2 will overcome the elastic force of the compression spring 15 and push the conical spool 6 to move to the right. When the conical spool 6 gradually moves to the right, the conical spool 6 will block the gap between the conical spool 6 and the conical ring 5 on a large area, so as to reduce the flow rate and slow down the descending speed of the forklift fork.

[0030] Rotate the adjusting screw 9. By using the screw drive between the adjusting screw 9 and the locking nut 11, the position of the piston 8 can be changed, so as to control the contraction strength of the compression spring 15 by moving the piston 8 closer to or away from the conical spool 6. Compared with the prior art, when the device drops valuable items under light load, the piston 8 can be driven away from the conical spool 6, so as to reduce the elastic force of the compression spring 15, forcing the hydraulic oil to require very little power to push the conical spool 6 close to the conical ring 5, so as to slow down the descending speed of the forklift fork under light load and avoid damage to valuable goods caused by too fast descending speed.

[0031] When the load on the forklift forks is too large, the conical valve core 6 will completely block the conical ring 5. At this time, the hydraulic oil will slowly flow into the valve body 1 along the oil drain hole 7, avoiding the problem that the forklift forks cannot descend due to the non-flow of hydraulic oil caused by excessive load on the forklift forks.

[0032] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A special speed limit valve for a forklift, comprising a valve body (1) and a valve cover (2), characterized in that: An oil inlet (3) is provided on the surface of the valve body (1), an oil drain port (4) is provided on the surface of the valve cover (2), an assembly structure is provided between the valve body (1) and the valve cover (2), a valve core structure is provided inside the valve body (1), and an oil resistance adjusting structure is provided on the right side of the valve core structure; The valve core structure includes a conical ring (5) fixedly installed on the inner ring surface of the valve body (1), and a conical valve core (6) slidably installed on the inner wall of the conical ring (5), and an oil drain hole (7) is opened at the central position of the conical valve core (6); The oil resistance adjusting structure includes a piston (8) slidably installed on the inner wall of the valve body (1), and an adjusting screw (9) slidably connected to the right end of the valve body (1) through a sealing ring (17). The left end of the adjusting screw (9) extends into the interior of the valve body (1) and is rotatably connected to the right end of the piston (8), and a plurality of oil delivery holes (10) are arranged in a circumferential array on the surface of the piston (8).

2. The special speed limit valve for forklift according to claim 1, characterized in that: The piston (8) is located on the right side of the conical valve core (6). The right end of the adjusting screw (9) extends to the outside of the valve body (1) and is threadedly connected with a locking nut (11), and the left end of the locking nut (11) is fixedly connected to the right end of the valve body (1).

3. The special speed-limiting valve for forklift trucks according to claim 1, characterized in that: The assembly structure includes an external thread (12) opened on the outer ring surface of the valve body (1), and an internal thread (13) opened on the inner ring surface of the valve cover (2), and a sealing ring (14) is provided inside the valve cover (2).

4. A special speed limit valve for forklifts according to claim 1, characterized in that: A through hole communicating with the oil drain hole (7) is opened at the right end of the conical valve core (6), a compression spring (15) is provided on the inner wall of the through hole, and one end of the compression spring (15) away from the conical valve core (6) abuts against the left end of the piston (8).

5. The special speed limit valve for forklift according to claim 1, characterized in that: The oil inlet (3) communicates with the interior of the valve body (1), and the oil drain port (4) communicates with the interior of the valve cover (2).

6. A special speed limit valve for forklifts according to claim 1, characterized in that: A plurality of baffles (16) for restricting excessive movement of the conical valve core (6) are arranged in a circumferential array at the right end of the conical valve core (6).

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