Pneumatic actuator limit device

Abstract

This utility model provides a pneumatic actuator closing limit device, relating to the technical field of pneumatic actuators for valves. One end of the cylinder structure is provided with a limiting housing support, forming an accommodating space between the cylinder structure and the limiting housing support. One end of the limiting push rod structure passes through the limiting housing support and the cylinder structure sequentially and is used to connect to an external valve core. The cylinder structure is used to drive the piston structure, along with the limiting push rod structure, to move in a direction away from the limiting housing support by injecting compressed air into the accommodating space. One end of an elastic element is connected to the cylinder structure, and the other end is connected to the piston structure. The elastic element is used to push the piston structure to move in a direction toward the limiting housing support. This utility model alleviates the technical problems of inaccurate adjustment and poor reliability in existing pneumatic valve closing limit devices, thereby improving the stability of the process flow and reducing equipment maintenance costs and downtime.

Description

Technical Field

[0001] This utility model relates to the technical field of pneumatic actuators for valves, and in particular to a limit device for a pneumatic actuator. Background Technology

[0002] In recent years, with the rapid development of my country's energy industry, especially in the fields of petroleum, chemical, natural gas and power, the application of automated control systems has become increasingly widespread, and the market has put forward higher and stricter requirements for the regulating performance of pneumatic actuators for valves.

[0003] As a key component in fluid control systems, the accuracy, reliability, and response speed of valve control directly affect the overall system's operational efficiency and safety. Currently, most pneumatic actuators for valves on the market rely on traditional mechanical or pneumatic control methods to achieve the air-to-close limit function of valves.

[0004] Traditional pneumatic actuators often suffer from problems such as inaccurate limit switching, difficulty in adjustment, and susceptibility to failure when controlling valve opening and closing. Especially in long-term, high-frequency operating environments, the stability and accuracy of limit devices are often difficult to guarantee. This not only affects the stability of the process flow but also increases equipment maintenance costs and downtime. Utility Model Content

[0005] The purpose of this utility model is to provide a pneumatic actuator closing limit device to alleviate the technical problems of inaccurate adjustment and poor reliability of the valve air closing limit device in the prior art, thereby improving the stability of the process flow and reducing the maintenance cost and downtime of the equipment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This utility model provides a pneumatic actuator limit device, including a cylinder structure, a limit housing bracket, a limit push rod structure, a piston structure and an elastic element. One end of the cylinder structure is provided with the limit housing bracket, and an accommodating space is formed between the cylinder structure and the limit housing bracket. The cylinder structure is used to connect to an external air compression device. One end of the limiting push rod structure passes through the limiting housing bracket and the cylinder structure in sequence and is used to connect to the external valve core, and the limiting push rod structure is connected to the piston structure. The piston structure is disposed within the accommodating space, and the cylinder structure is used to drive the piston structure together with the limiting push rod structure to move in a direction away from the limiting housing support by injecting compressed air into the accommodating space. One end of the elastic element is connected to the cylinder structure, and the other end is connected to the piston structure. The elastic element is used to push the piston structure to move in the direction toward the limiting housing bracket.

[0007] Furthermore, the cylinder structure includes a cylinder body, a bottom cover assembly, and a bracket. The first end of the cylinder body is connected to the limiting housing bracket, and the second end of the cylinder body is connected to the bottom cover assembly, so that the accommodating space is provided inside the cylinder body. The first end of the cylinder body is provided with an air inlet for connecting to the air compression device; The bracket is connected to the side of the bottom cover assembly that faces away from the cylinder body.

[0008] Furthermore, the bottom cover assembly includes a bottom cover body, a bottom cover annular ring, and a retaining ring. The bottom cover body has a protrusion along its edge, which is connected to a groove formed at the second end edge of the cylinder body. The bottom cover body also has a bottom cover annular ring along its edge, which abuts against the inner wall of the cylinder body. The retaining ring is connected to the second end of the cylinder body and is supported at the bottom of the bottom cover body.

[0009] Furthermore, the bottom cover assembly also includes a first wire retaining ring, a first push rod bushing, and a first push rod annular ring; One end of the limiting push rod structure passes through the bottom cover body and extends into the bracket; The first push rod bushing is connected to the bottom cover body, and the first push rod bushing is sleeved on the outside of the limiting push rod structure; The first wire retaining ring is disposed at the first end of the first push rod bushing and connected to the bottom cover body, and the first wire retaining ring is sleeved on the outside of the limiting push rod structure; The first push rod annular ring is disposed at the second end of the first push rod bushing and connected to the bottom cover body, and the first push rod annular ring is sleeved on the outside of the limiting push rod structure.

[0010] Furthermore, the limiting push rod structure includes a lower push rod, an upper push rod, an elastic cylindrical pin, and an adjusting nut. One end of the upper push rod is connected to the lower push rod through the elastic cylindrical pin, and the other end of the upper push rod passes through the limiting housing bracket and is provided with a threaded portion, and is connected to the adjusting nut. The end of the push rod away from the elastic cylindrical pin extends into the bracket and connects to the valve core.

[0011] Furthermore, the end of the lower push rod opposite to the elastic cylindrical pin is provided with a push rod clamp, and the push rod clamp is provided with a pointer; The bracket is equipped with a travel scale; The pointer is used to indicate the corresponding scale position on the travel scale.

[0012] Furthermore, the push rod is equipped with a sliding element; The support frame is equipped with a slide rail; The slider is slidably connected to the slide rail.

[0013] Furthermore, a sealing sleeve is fitted onto the end of the lower push rod that is away from the elastic cylindrical pin, and the sealing sleeve is used to seal the joint between the lower push rod and the bottom cover assembly.

[0014] Furthermore, the outer wall of the limiting housing bracket is provided with a positioning ring along the circumferential direction, and the positioning ring is used to seal the gap between the limiting housing bracket and the cylinder structure; The inner wall of the limiting housing bracket is provided with a second push rod annular ring, a second push rod bushing, and a second wire retaining ring. The second push rod annular ring, the second push rod bushing, and the second wire retaining ring are all sleeved on the outside of the limiting push rod structure. The top of the limiting housing bracket is provided with a dust cover, which is used to cover the top of the limiting push rod structure.

[0015] Furthermore, the piston structure includes a piston body, a piston retaining sleeve, and a piston annular ring. The piston retaining sleeve is provided at the bottom of the piston body, and both the piston body and the piston retaining sleeve are connected to the limiting push rod structure. A piston annular ring is provided at the edge of the piston body, and the piston annular ring abuts against the inner wall of the cylinder structure.

[0016] This utility model can achieve the following beneficial effects: This utility model provides a pneumatic actuator limiting device, including a cylinder structure, a limiting housing support, a limiting push rod structure, a piston structure, and an elastic element. One end of the cylinder structure is provided with the limiting housing support, and an accommodating space is formed between the cylinder structure and the limiting housing support. The cylinder structure is used to connect to an external air compression device. One end of the limiting push rod structure passes through the limiting housing support and the cylinder structure in sequence and is used to connect to an external valve core. The limiting push rod structure is also connected to the piston structure. The piston structure is located within the accommodating space. The cylinder structure is used to drive the piston structure, along with the limiting push rod structure, to move in a direction away from the limiting housing support by injecting compressed air into the accommodating space. One end of the elastic element is connected to the cylinder structure, and the other end is connected to the piston structure. The elastic element is used to push the piston structure to move in a direction toward the limiting housing support.

[0017] In this invention, the top of the cylinder structure is connected to the limiting housing bracket, and the limiting push rod structure is inserted through the limiting housing bracket and the cylinder structure to form an accommodating space between the cylinder structure and the limiting housing bracket. A piston structure is slidably arranged in this accommodating space and is connected to the limiting push rod structure. When compressed air is injected into the accommodating space through an air compression device, the air pressure in the accommodating space increases, thereby pushing the piston structure to move. During the movement of the piston structure, it drives the limiting push rod structure to move synchronously, so as to move the valve core connected to the limiting push rod structure.

[0018] Compared with the prior art, the pneumatic actuator limit device provided by this utility model injects compressed air into the cylinder structure to make the piston structure move, thereby driving the limit push rod structure and the valve core to move synchronously, thus realizing the accuracy and reliability of regulating the valve, and making the entire process more stable.

[0019] In summary, this utility model at least alleviates the technical problems of inaccurate adjustment and poor reliability of valve air-closing limit devices in the prior art, thereby improving the stability of the process flow and reducing equipment maintenance costs and downtime. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the overall cross-sectional structure of the pneumatic actuator limit device provided in this embodiment of the utility model; Figure 2 A partial cross-sectional schematic diagram of the first part of the pneumatic actuator limit device provided in an embodiment of this utility model; Figure 3 This is a partial cross-sectional schematic diagram of the second part of the pneumatic actuator limit device provided in an embodiment of the present invention; Figure 4 A schematic cross-sectional view of the limiting portion of the pneumatic actuator limiting device provided in an embodiment of this utility model.

[0022] Icons: 1-Cylinder block structure; 11-Cylinder block body; 111-Intake port; 12-Bottom cover assembly; 121-Bottom cover body; 1211-Protrusion; 122-Bottom cover annular ring; 123-Snap ring; 124-First wire retaining ring; 125-First push rod bushing; 126-First push rod annular ring; 13-Bracket; 131-Stroke scale; 132-Slide rail; 2-Limit housing bracket; 21-Positioning annular ring; 22-Second push rod 23-Second push rod bushing; 24-Second wire retaining ring; 25-Dust cover; 3-Limiting push rod structure; 31-Lower push rod; 311-Sealing sleeve; 312-Push rod clamp; 3121-Pointer; 3122-Sliding part; 32-Upper push rod; 321-Threaded part; 33-Elastic cylindrical pin; 34-Adjusting nut; 4-Piston structure; 41-Piston body; 42-Piston fixing sleeve; 43-Piston annular ring; 5-Elastic part. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of this utility model, it should be noted that the terms "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] Example 1 This embodiment provides a pneumatic actuator limit switch, referring to... Figure 1 The pneumatic actuator's limiting device includes a cylinder structure 1, a limiting housing support 2, a limiting push rod structure 3, a piston structure 4, and an elastic element 5. One end of the cylinder structure 1 is provided with the limiting housing support 2, and an accommodating space is formed between the cylinder structure 1 and the limiting housing support 2. The cylinder structure 1 is used to connect to an external air compression device. One end of the limiting push rod structure 3 passes through the limiting housing support 2 and the cylinder structure 1 in sequence and is used to connect to an external valve core. The limiting push rod structure 3 is also connected to the piston structure 4. The piston structure 4 is located within the accommodating space. The cylinder structure 1 is used to drive the piston structure 4, together with the limiting push rod structure 3, to move in a direction away from the limiting housing support 2 by injecting compressed air into the accommodating space. One end of the elastic element 5 is connected to the cylinder structure 1, and the other end is connected to the piston structure 4. The elastic element 5 is used to push the piston structure 4 to move in a direction toward the limiting housing support 2.

[0031] This utility model embodiment at least alleviates the technical problems of inaccurate adjustment and poor reliability of valve air-closing limit devices in the prior art, thereby improving the stability of the process flow and reducing equipment maintenance costs and downtime.

[0032] In this embodiment of the present invention, the top of the cylinder structure 1 is connected to the limiting housing bracket 2, and the limiting push rod structure 3 is inserted through the limiting housing bracket 2 and the cylinder structure 1 to form an accommodating space between the cylinder structure 1 and the limiting housing bracket 2. A piston structure 4 is slidably arranged in this accommodating space. The piston structure 4 is connected to the limiting push rod structure 3, so that when compressed air is injected into the accommodating space by an air compression device, the air pressure in the accommodating space increases, thereby pushing the piston structure 4 to move. During the movement of the piston structure 4, it drives the limiting push rod structure 3 to move synchronously, so as to move the valve core connected to the limiting push rod structure 3.

[0033] Compared with the prior art, the pneumatic actuator limit device provided in this embodiment of the utility model injects compressed air into the cylinder structure 1 to make the piston structure 4 move, thereby driving the limit push rod structure 3 and the valve core to move synchronously, thereby realizing the accuracy and reliability of regulating the valve, and making the entire process more stable.

[0034] In an optional implementation of this embodiment, refer to Figure 1 and Figure 2 The cylinder structure 1 includes a cylinder body 11, a bottom cover assembly 12, and a bracket 13. The first end of the cylinder body 11 is connected to the limiting housing bracket 2, and the second end of the cylinder body 11 is connected to the bottom cover assembly 12, so that the cylinder body 11 has an accommodating space. The first end of the cylinder body 11 has an air inlet 111 for connecting to an air compression device. The bracket 13 is connected to the side of the bottom cover assembly 12 away from the cylinder body 11.

[0035] Specifically: the bottom of the cylinder body 11 is connected to the bottom cover assembly 12, and the top of the cylinder body 11 is connected to the limiting housing bracket 2. A bracket 13 is provided at the bottom of the bottom cover assembly 12. The limiting push rod structure 3 passes through the limiting housing bracket 2, the cylinder body 11, and the bottom cover assembly 12 in sequence and is inserted into the bracket 13. In use, compressed air is injected into the accommodating space through the air inlet 111 located on one side of the top of the cylinder body 11, so that the air pressure in the accommodating space changes, thereby driving the piston structure 4 to move towards the bottom cover assembly 12, and synchronously driving the limiting push rod structure 3 to move.

[0036] Furthermore, referring to Figure 2 The bottom cover assembly 12 includes a bottom cover body 121, a bottom cover annular ring 122, and a retaining ring 123. The bottom cover body 121 has a protrusion 1211 along its edge, which is connected to a groove formed at the second end edge of the cylinder body 11. The bottom cover body 121 also has a bottom cover annular ring 122 along its edge, which abuts against the inner wall of the cylinder body 11. The retaining ring 123 is connected to the second end of the cylinder body 11 and is supported at the bottom of the bottom cover body 121.

[0037] Specifically: a through hole is provided at the center of the bottom cover body 121 for the limit push rod structure 3 to pass through, and a bottom cover annular ring 122 is provided around the edge of the bottom cover body 121. The bottom cover annular ring 122 is in close contact with the inner wall of the cylinder body 11 to seal the gap between the cylinder body 11 and the bottom cover body 121; while the retaining ring 123 is engaged in the annular groove at the bottom of the cylinder body 11 and is used to support the bottom cover body 121.

[0038] Furthermore, referring to Figure 2 The bottom cover assembly 12 also includes a first wire retaining ring 124, a first push rod bushing 125, and a first push rod annular ring 126; one end of the limiting push rod structure 3 passes through the bottom cover body 121 and extends into the bracket 13; the first push rod bushing 125 is connected to the bottom cover body 121 and is sleeved on the outside of the limiting push rod structure 3; the first wire retaining ring 124 is located at the first end of the first push rod bushing 125 and is connected to the bottom cover body 121, and is sleeved on the outside of the limiting push rod structure 3; the first push rod annular ring 126 is located at the second end of the first push rod bushing 125 and is connected to the bottom cover body 121, and is sleeved on the outside of the limiting push rod structure 3.

[0039] Specifically: a first push rod bushing 125 is provided in the through hole of the bottom cover body 121, and the first push rod bushing 125 is clamped on the outside of the limiting push rod structure 3; while the first push rod annular ring 126 is located below the first push rod bushing 125 and clamped on the outside of the limiting push rod structure 3, so as to achieve the sealing between the limiting push rod structure 3 and the bottom cover body 121 through the first push rod annular ring 126; while the first steel wire retaining ring 124 is distributed along the circumference of the through hole and is engaged with the hole wall of the bottom cover body 121, so as to achieve the limiting and fixing of the first push rod bushing 125.

[0040] In an optional implementation of this embodiment, refer to Figure 3 The limiting push rod structure 3 includes a lower push rod 31, an upper push rod 32, an elastic cylindrical pin 33, and an adjusting nut 34. One end of the upper push rod 32 is connected to the lower push rod 31 through the elastic cylindrical pin 33, and the other end of the upper push rod 32 passes through the limiting housing bracket 2 and is provided with a threaded part 321, and is connected to the adjusting nut 34. The end of the lower push rod 31 away from the elastic cylindrical pin 33 extends into the bracket 13 and is connected to the valve core.

[0041] Specifically: the lower push rod 31 and the upper push rod 32 are connected by an elastic cylindrical pin 33, so that the lower push rod 31 and the upper push rod 32 are connected end to end. Among them, the lower push rod 31 is connected to the piston structure 4, and the bottom of the lower push rod 31 passes through the bottom cover body 121 and extends into the bracket 13; the lower push rod 31 is used to connect to the bottom cover body 121 through the first steel wire retaining ring 124, the first push rod bushing 125 and the first push rod annular ring 126. The bottom of the lower push rod 31 is provided with a valve core, which can move down with the lower push rod 31 until it passes through the bottom of the bracket 13; the top of the upper push rod 32 is provided with a threaded part 321, and the threaded part 321 is provided with an adjusting nut 34. Preferably, there are two adjusting nuts 34, and the two adjusting nuts 34 are used to determine the downward movement length of the limiting push rod structure 3 by adjusting their positions on the threaded part 321.

[0042] Furthermore, referring to Figure 2 The lower push rod 31 is provided with a push rod clamp 312 at the end away from the elastic cylindrical pin 33, and the push rod clamp 312 is provided with a pointer 3121; the bracket 13 is provided with a travel scale 131; the pointer 3121 is used to indicate the corresponding scale position on the travel scale 131.

[0043] Specifically: The bottom of the push rod 31 is equipped with a pointer 3121, and correspondingly, the bracket 13 is equipped with a travel scale 131, which is set along the extension direction of the push rod 31. In use, as the push rod 31 moves downward, the pointer 3121 points to the corresponding mark on the travel scale 131, thereby determining the downward movement length of the push rod 31.

[0044] Furthermore, referring to Figure 2 The push rod clamp 312 is provided with a sliding member 3122; the bracket 13 is provided with a slide rail 132; the sliding member 3122 is slidably connected to the slide rail 132.

[0045] Specifically: the push rod clamp 312 is provided with a slider 3122, which is located at the opposite end of the pointer 3121, and the bracket 13 is provided with a slide rail 132 along the extension direction of the lower push rod 31. The slider 3122 is slidably connected to the slide rail 132 so that the lower push rod 31 moves more smoothly.

[0046] In an optional implementation of this embodiment, refer to Figure 2 A sealing sleeve 311 is fitted on the end of the lower push rod 31 away from the elastic cylindrical pin 33. The sealing sleeve 311 is used to seal the joint between the lower push rod 31 and the bottom cover assembly 12.

[0047] Specifically: the sealing sleeve 311 is located below the bottom cover body 121, and the sealing sleeve 311 is clamped on the outside of the lower push rod 31. The sealing sleeve 311 is used to seal the joint between the lower push rod 31 and the bottom cover assembly 12 to prevent dust or other dirt or moisture from entering the accommodating space.

[0048] In an optional implementation of this embodiment, refer to Figure 4 The outer wall of the limiting housing bracket 2 is provided with a positioning ring 21 along the circumference. The positioning ring 21 is used to seal the gap between the limiting housing bracket 2 and the cylinder structure 1. The inner wall of the limiting housing bracket 2 is provided with a second push rod ring 22, a second push rod bushing 23 and a second wire retaining ring 24. The second push rod ring 22, the second push rod bushing 23 and the second wire retaining ring 24 are all sleeved on the outside of the limiting push rod structure 3. The top of the limiting housing bracket 2 is provided with a dust cover 25, which is used to cover the top of the limiting push rod structure 3.

[0049] Specifically: the limiting housing bracket 2 is connected to the cylinder body 11, and the limiting housing bracket 2 is penetrated by the upper push rod 32 along its extension direction. The threaded portion 321 at the top of the upper push rod 32 is located on the outside of the limiting housing bracket 2. The wall of the through hole of the limiting housing bracket 2 is provided with a second push rod annular ring 22, a second push rod bushing 23, and a second wire retaining ring 24 from top to bottom. The second push rod annular ring 22 and the second push rod bushing 23 are both clamped to the outer wall of the upper push rod 32. The second wire retaining ring 24 is engaged with the limiting housing bracket 2 and supported at the bottom of the second push rod bushing 23. The dust cover 25 is detachably connected to the limiting housing bracket 2 by bolts, and the dust cover 25 is used to cover the outside of the threaded portion 321 and the adjusting nut 34.

[0050] In an optional implementation of this embodiment, refer to Figure 3 The piston structure 4 includes a piston body 41, a piston retaining sleeve 42, and a piston annular ring 43. The piston body 41 is provided with a piston retaining sleeve 42 at its bottom, and both the piston body 41 and the piston retaining sleeve 42 are connected to the limiting push rod structure 3. The piston body 41 is provided with a piston annular ring 43 at its edge, and the piston annular ring 43 abuts against the inner wall of the cylinder structure 1.

[0051] Specifically: A piston retaining sleeve 42 is provided at the bottom of the piston body 41. A lower push rod 31 passes through the piston body 41 and the piston retaining sleeve 42 in sequence. The outer wall of the lower push rod 31 has a protruding section. The top of this protruding section abuts against the bottom of the piston retaining sleeve 42, so that the piston retaining sleeve 42 moves down and pushes the protruding section and the lower push rod 31 down synchronously. After the downward movement is completed, the injected compressed air is released, and the piston body 41 connected to the elastic element 5 moves up and resets due to the restoring thrust of the compressed elastic element 5. It should be noted that the elastic element 5 can be a spring. A piston annular ring 43 is provided along the circumferential edge of the piston body 41. The piston annular ring 43 is used to seal the gap between the piston body 41 and the inner wall of the cylinder body 11 to prevent air from flowing between the upper and lower chambers of the piston body 41 when compressed air is injected, thereby avoiding the situation of poor sealing.

[0052] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. The above embodiments in this specification are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of this utility model.

Claims

1. A limit switch for a pneumatic actuator, characterized in that, It includes a cylinder structure (1), a limiting housing bracket (2), a limiting push rod structure (3), a piston structure (4), and an elastic element (5). One end of the cylinder structure (1) is provided with the limiting housing bracket (2), and an accommodating space is formed between the cylinder structure (1) and the limiting housing bracket (2). The cylinder structure (1) is used to connect to an external air compression device. One end of the limiting push rod structure (3) passes through the limiting housing bracket (2) and the cylinder structure (1) in sequence and is used to connect with the external valve core, and the limiting push rod structure (3) is connected with the piston structure (4). The piston structure (4) is located in the accommodating space, and the cylinder structure (1) is used to drive the piston structure (4) together with the limiting push rod structure (3) to move in a direction away from the limiting housing support (2) by injecting compressed air into the accommodating space. One end of the elastic element (5) is connected to the cylinder structure (1), and the other end is connected to the piston structure (4). The elastic element (5) is used to push the piston structure (4) to move in the direction toward the limiting housing bracket (2).

2. The pneumatic actuator limit device according to claim 1, characterized in that, The cylinder structure (1) includes a cylinder body (11), a bottom cover assembly (12) and a bracket (13). The first end of the cylinder body (11) is connected to the limiting housing bracket (2), and the second end of the cylinder body (11) is connected to the bottom cover assembly (12), so that the cylinder body (11) has the accommodating space. The first end of the cylinder body (11) is provided with an air inlet (111) for connecting to the air compression device. The bracket (13) is connected to the side of the bottom cover assembly (12) that is away from the cylinder body (11).

3. The pneumatic actuator limit device according to claim 2, characterized in that, The bottom cover assembly (12) includes a bottom cover body (121), a bottom cover annular ring (122), and a retaining ring (123). The bottom cover body (121) has a protrusion (1211) along its edge. The protrusion (1211) is connected to a groove opened at the second end edge of the cylinder body (11). The bottom cover body (121) has a bottom cover annular ring (122) along its edge. The bottom cover annular ring (122) abuts against the inner wall of the cylinder body (11). The retaining ring (123) is connected to the second end of the cylinder body (11), and the retaining ring (123) is supported at the bottom of the bottom cover body (121).

4. The pneumatic actuator limit device according to claim 3, characterized in that, The bottom cover assembly (12) also includes a first wire retaining ring (124), a first push rod bushing (125), and a first push rod annular ring (126). One end of the limiting push rod structure (3) passes through the bottom cover body (121) and extends into the bracket (13); The first push rod bushing (125) is connected to the bottom cover body (121), and the first push rod bushing (125) is sleeved on the outside of the limiting push rod structure (3); The first wire retaining ring (124) is disposed at the first end of the first push rod bushing (125) and connected to the bottom cover body (121), and the first wire retaining ring (124) is sleeved on the outside of the limiting push rod structure (3); The first push rod ring (126) is located at the second end of the first push rod bushing (125) and connected to the bottom cover body (121), and the first push rod ring (126) is sleeved on the outside of the limiting push rod structure (3).

5. The pneumatic actuator limit device according to claim 2, characterized in that, The limiting push rod structure (3) includes a lower push rod (31), an upper push rod (32), an elastic cylindrical pin (33), and an adjusting nut (34). One end of the upper push rod (32) is connected to the lower push rod (31) through the elastic cylindrical pin (33), and the other end of the upper push rod (32) passes through the limiting housing bracket (2) and is provided with a threaded part (321), and is connected to the adjusting nut (34). The end of the lower push rod (31) away from the elastic cylindrical pin (33) extends into the bracket (13) and is connected to the valve core.

6. The pneumatic actuator limit device according to claim 5, characterized in that, The lower push rod (31) is provided with a push rod clamp (312) at the end away from the elastic cylindrical pin (33), and the push rod clamp (312) is provided with a pointer (3121). The bracket (13) is equipped with a travel scale (131); The pointer (3121) is used to indicate the corresponding scale position on the travel scale (131).

7. The pneumatic actuator limit device according to claim 6, characterized in that, The push rod clamp (312) is provided with a sliding member (3122); The bracket (13) is provided with a slide (132); The slider (3122) is slidably connected to the slide rail (132).

8. The pneumatic actuator limit device according to claim 5, characterized in that, The end of the lower push rod (31) away from the elastic cylindrical pin (33) is fitted with a sealing sleeve (311), which is used to seal the joint between the lower push rod (31) and the bottom cover assembly (12).

9. The pneumatic actuator limit device according to claim 1, characterized in that, The outer wall of the limiting housing bracket (2) is provided with a positioning ring (21) along the circumferential direction. The positioning ring (21) is used to seal the gap between the limiting housing bracket (2) and the cylinder structure (1). The inner wall of the limiting housing bracket (2) is provided with a second push rod annular ring (22), a second push rod bushing (23), and a second wire retaining ring (24). The second push rod annular ring (22), the second push rod bushing (23), and the second wire retaining ring (24) are all sleeved on the outside of the limiting push rod structure (3). The top of the limiting housing bracket (2) is provided with a dust cover (25), which is used to cover the top of the limiting push rod structure (3).

10. The pneumatic actuator limit device according to claim 1, characterized in that, The piston structure (4) includes a piston body (41), a piston fixing sleeve (42) and a piston ring (43). The piston fixing sleeve (42) is provided at the bottom of the piston body (41), and both the piston body (41) and the piston fixing sleeve (42) are connected to the limiting push rod structure (3). The piston body (41) is provided with a piston ring (43) at its edge, and the piston ring (43) abuts against the inner wall of the cylinder structure (1).

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