Pinion and rack type pneumatic actuating mechanism

Abstract

The utility model provides a gear and rack type pneumatic actuating mechanism which comprises a box body with openings at two ends, a gear shaft arranged on the box body in a vertically penetrating manner, two piston mechanisms arranged in the box body and end covers arranged at two ends of the box body, and the end covers seal the openings corresponding to the end covers; the gear shaft is rotationally arranged on the box body and is provided with a first rotating part and a second rotating part which rotate relative to the top wall and the bottom wall of the box body respectively, and the diameters of the first rotating part and the second rotating part are the same; in the length direction of the box body, the two piston mechanisms are arranged on the two sides of the gear shaft respectively, each piston mechanism comprises a piston arranged in the box body in a sliding mode and a rack arranged on the piston, and the racks are meshed with the gear shaft. The gear rack type pneumatic actuating mechanism disclosed by the utility model has higher use stability.

Description

Technical Field

[0001] The utility model relates to the technical field of valve control, in particular to a gear rack type pneumatic actuator. Background Art

[0002] Pneumatic actuators are commonly known as pneumatic heads or pneumatic actuators. They can be divided into three categories according to the energy form: pneumatic, electric and hydraulic, to suit different occasions. At the same time, pneumatic actuators can also be divided into two types: single-acting and double-acting. Among them, the switching action of the actuator is driven by the air source, which is called a double-acting pneumatic actuator. The actuator is only driven by the air source to open or close, and the opposite action is reset by the spring, which is called a single-acting one.

[0003] Pneumatic actuators include diaphragm type, piston type, scotch fork type and gear rack type. Because gear rack pneumatic actuators have the advantages of simple structure, stable and reliable operation, safety and explosion-proof, they are widely used in production processes with high safety requirements such as power generation, chemical industry, and oil refining.

[0004] The gear shaft of the existing rack and pinion pneumatic actuator is usually installed from the bottom of the box and arranged perpendicular to the horizontal axis (i.e., the length direction) of the box. At the same time, the gear shaft penetrates and is rotatably arranged on the box. However, due to the different diameters of the rotating parts of the gear shaft relative to the top wall and the bottom wall (the two opposite side walls along the height direction of the box) of the box, the diameter of the rotating part of the gear shaft corresponding to the bottom wall is generally larger, which makes it easy for the gear shaft to shake along its own axis or fall out of the bottom (part) of the box due to inconsistent air pressure during operation, causing the equipment to become unstable or even damaged, which is not conducive to ensuring operation stability. Utility Model Content

[0005] In view of this, the utility model aims to provide a rack and pinion pneumatic actuator with higher operating stability.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] A gear rack type pneumatic actuator comprises a box body with openings at both ends, a gear shaft provided on the box body so as to penetrate the box body from top to bottom, two piston mechanisms provided in the box body, and end covers provided at both ends of the box body, wherein the end covers block the openings corresponding thereto;

[0008] The gear shaft is rotatably arranged on the box body and has a first rotating part and a second rotating part which rotate relative to the top wall and the bottom wall of the box body respectively, and the diameters of the first rotating part and the second rotating part are the same;

[0009] In the length direction of the box body, the two piston mechanisms are respectively arranged on both sides of the gear shaft, and each of the piston mechanisms includes a piston slidably arranged in the box body, and a rack arranged on the piston, and the rack is meshed with the gear shaft.

[0010] Further, the first rotating part is provided with a first sealing ring and a first bushing, and the first sealing ring and the first bushing are both clamped between the first rotating part and the top wall; and / or, the second rotating part is provided with a second sealing ring and a second bushing, and the second sealing ring and the second bushing are both clamped between the second rotating part and the bottom wall.

[0011] Furthermore, the first rotating part is provided with a first groove and a second groove which are axially extended around the gear shaft, the first sealing ring is arranged in the first groove, and the first bushing is arranged in the second groove; the second rotating part is provided with a third groove and a fourth groove which are axially extended around the gear shaft, the second sealing ring is arranged in the third groove, and the second bushing is arranged in the fourth groove.

[0012] Furthermore, an adjusting block is provided on the gear shaft, and a limiting bolt for limiting the rotation range of the adjusting block is provided on the box body.

[0013] Furthermore, the adjusting block is located between the top wall and the tooth portion of the gear shaft, and a first gasket is sandwiched between the adjusting block and the top wall.

[0014] Furthermore, a second gasket and a retaining spring are provided on the portion of the gear shaft extending out of the top wall, and the second gasket is fixed between the retaining spring and the top wall.

[0015] Furthermore, it also includes an elastic component arranged on the side of the piston away from the rack; the elastic component is located between the piston and the corresponding end cover, and includes a first sleeve arranged on the piston, a second sleeve arranged on the end cover, a guide rod slidably arranged in the first sleeve and the second sleeve, and a spring sleeved on the first sleeve, the guide rod and the second sleeve.

[0016] Furthermore, the piston is provided with a first mounting groove, and the first sleeve is arranged in the first mounting groove; and / or, the end cover is provided with a second mounting groove, and the second sleeve is arranged in the second mounting groove.

[0017] Furthermore, the tooth portion of the gear shaft includes a plurality of meshing teeth arranged in sequence around the axial direction of the gear shaft, and a tooth groove is formed between two adjacent meshing teeth; a limiting portion is provided at both ends of the tooth groove, and each limiting portion is used to limit each rack from disengaging from the tooth groove in the axial direction of the gear shaft.

[0018] Furthermore, the limiting portion includes limiting protrusions arranged at both ends of the tooth groove, and a limiting inclined surface is formed on the side of each limiting protrusion facing the tooth groove, and each limiting inclined surface extends from the middle to the end along the axial direction of the gear shaft, and is arranged to be inclined outward along the radial direction of the gear shaft.

[0019] Compared with the prior art, the utility model has the following advantages:

[0020] The rack and pinion pneumatic actuator described in the utility model can make the air pressure at both ends of the gear shaft the same by setting the first rotating part and the second rotating part to have the same diameter, so as to avoid the problem of the gear shaft shaking along its own axis or even falling out of the box during rotation, thereby ensuring the overall operating stability of the equipment and having a good use effect.

[0021] In addition, the coordinated use of the first sealing ring and the first bushing is conducive to ensuring the sealing between the first rotating part and the top wall, and can avoid hard friction between the two. At the same time, the coordinated use of the second sealing ring and the second bushing is also conducive to ensuring the sealing between the second rotating part and the bottom wall, and avoiding hard friction between the two, thereby improving the service life. The provision of each groove can facilitate the arrangement and installation of each sealing ring and each bushing.

[0022] Secondly, the use of the adjustment block and the limit bolt can prevent the gear shaft from rotating too far and disengaging from the racks, thus ensuring operational stability. The setting of the first gasket can avoid hard friction between the adjustment block and the top wall and relieve vibration. The use of the second gasket and the retaining spring can facilitate the disassembly and assembly of the second gasket and relieve vibration.

[0023] In addition, the coordinated use of the first sleeve, the second sleeve, the guide rod and the spring has a simple structure and high stability. The use of the first mounting groove and the second mounting groove is conducive to the assembly of the elastic component. By setting the limiting portion, it is possible to prevent each rack from being separated from each tooth groove and causing structural instability. The limiting portion includes a limiting protrusion and a limiting inclined surface, which can guide each rack to reset when each rack has a tendency to be separated from each tooth groove, thereby preventing each rack from being separated from each tooth groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0025] Figure 1 It is a schematic diagram of the overall structure of the rack and pinion pneumatic actuator according to an embodiment of the utility model;

[0026] Figure 2 for Figure 1 A schematic diagram of the structure from another perspective of the structure shown in ;

[0027] Figure 3 It is a structural schematic diagram of the gear shaft and the first piston mechanism and the second piston mechanism when they are assembled according to an embodiment of the utility model;

[0028] Figure 4 This is a schematic diagram of the structure of the gear shaft according to an embodiment of the utility model;

[0029] Figure 5 This is a schematic structural diagram of the first piston mechanism and the end cover when assembled according to an embodiment of the utility model;

[0030] Figure 6 This is a schematic diagram of the structure of the piston described in the embodiment of the utility model;

[0031] Figure 7 This is a schematic diagram of the structure of the end cover according to an embodiment of the utility model;

[0032] Figure 8 It is a partial structural schematic diagram of the elastic component according to an embodiment of the utility model;

[0033] Fig. 9 This is a schematic diagram of the structure of the adjustment block according to an embodiment of the utility model;

[0034] Description of reference numerals:

[0035] 1. Box body; 11. Top wall; 12. Bottom wall; 13. Side wall; 130. Air port; 14. End cover; 141. Second mounting groove; 15. Limit bolt;

[0036] 2. gear shaft; 20. keyway; 21. first rotating part; 211. first groove; 212. second groove; 22. second rotating part; 221. third groove; 222. fourth groove; 23. meshing teeth; 24. tooth groove; 25. limiting inclined surface; 26. fifth groove; 27. sixth groove;

[0037] 3. Piston mechanism; 31. Piston; 311. First mounting groove; 32. Rack; 33. Elastic component; 331. First sleeve; 332. Second sleeve; 333. Guide rod; 334. Spring;

[0038] 4. First sealing ring; 5. First bushing; 6. Second sealing ring; 7. Second bushing; 8. Adjustment block; 9. Second gasket; 100. Circlip. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0040] In the description of the present invention, it should be noted that if there are terms such as "upper", "lower", "inner", "outer" and the like indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, if there are terms such as "first" and "second", they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection" and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0043] This embodiment relates to a rack and pinion pneumatic actuator, the overall structure of which is as follows: Figures 1 to 9 As shown, the rack and pinion pneumatic actuator of this embodiment includes a box body 1 with openings at both ends, a gear shaft 2 that passes through the box body 1 from top to bottom, two piston mechanisms 3 arranged in the box body 1, and end covers 14 arranged at both ends of the box body 1, and the end covers 14 block the corresponding openings.

[0044] Furthermore, the gear shaft 2 is rotatably disposed on the housing 1 and has a first rotating portion 21 and a second rotating portion 22 that rotate relative to the top wall 11 and the bottom wall 12 of the housing 1, respectively, and the diameters of the first rotating portion 21 and the second rotating portion 22 are the same. In the length direction of the housing 1, two piston mechanisms 3 are disposed on both sides of the gear shaft 2, and each piston mechanism 3 includes a piston 31 slidably disposed in the housing 1, and a rack 32 disposed on the piston 31, and the rack 32 is meshed with the gear shaft 2.

[0045] At this time, as set above, by setting the diameters of the first rotating part 21 and the second rotating part 22 to be the same, the air pressure at both ends of the gear shaft 2 can be made the same, thereby preventing the gear shaft 2 from shaking along its own axial direction or even falling out of the box body 1 during rotation, thereby ensuring the overall operating stability of the equipment, thereby having a good use effect.

[0046] It should be noted that the bottom of the gear shaft 2 of this embodiment is provided with a keyway 20 for connecting to the valve stem in the valve. Moreover, the expressions related to directions in this embodiment are only used as an exemplary description of this embodiment. In specific implementation, the direction expressions in this embodiment vary with the different directions in which the box body 1 is set, that is, the directions in this embodiment refer to a relative coordinate system based on the box body 1.

[0047] Based on the above overall introduction, in detail, in this embodiment, as a preferred implementation form, Figure 4 As shown, the first rotating part 21 is sleeved with a first sealing ring 4 and a first bushing 5, and the first sealing ring 4 and the first bushing 5 are both sandwiched between the first rotating part 21 and the top wall 11. At the same time, as a preferred implementation form, the second rotating part 22 is sleeved with a second sealing ring 6 and a second bushing 7, and the second sealing ring 6 and the second bushing 7 are both sandwiched between the second rotating part 22 and the bottom wall 12.

[0048] It can be understood that the use of the first sealing ring 4 and the first bushing 5 is conducive to ensuring the sealing between the first rotating part 21 and the top wall 11, and can avoid hard friction between the two. At the same time, the use of the second sealing ring 6 and the second bushing 7 is also conducive to ensuring the sealing between the second rotating part 22 and the bottom wall 12, and avoid hard friction between the two, thereby improving the service life.

[0049] Furthermore, in this embodiment, as a preferred implementation form, the first rotating part 21 is provided with a first groove 211 and a second groove 212 extending axially around the gear shaft 2, the first sealing ring 4 is provided in the first groove 211, and the first bushing 5 is provided in the second groove 212. The second rotating part 22 is provided with a third groove 221 and a fourth groove 222 extending axially around the gear shaft 2, the second sealing ring 6 is provided in the third groove 221, and the second bushing 7 is provided in the fourth groove 222. In this way, the arrangement of each groove can facilitate the arrangement and installation of each sealing ring and each bushing.

[0050] In addition, in this embodiment, as a preferred implementation form, combined with Figure 4 and Fig. 9 As shown, the gear shaft 2 is provided with an adjustment block 8, and the housing 1 is provided with a limit bolt 15 for limiting the rotation range of the adjustment block 8. The use of the adjustment block 8 and the limit bolt 15 together can prevent the gear shaft 2 from rotating too much and disengaging from each rack 32, thereby ensuring operational stability.

[0051] In specific implementation, the gear shaft 2 of this embodiment is also provided with a fifth groove 26 extending around its own axial direction, and the fifth groove 26 is used to install the adjustment block 8. At this time, the structural shape of the adjustment block 8 can be set and adjusted accordingly according to the actual rotation range requirements of the gear shaft 2. For example, the adjustment block 8 can be roughly annular, so as to have a mounting hole that can be mounted in the fifth groove 26, and the adjustment block 8 is provided with a limiting surface for cooperating with the limiting bolt 15. Furthermore, the adjustment block 8 can be assembled from two sub-blocks to facilitate the assembly of the adjustment block 8 on the gear shaft 2.

[0052] At the same time, the limiting bolts 15 can be specifically arranged on one side wall 13 thereof, and the number of the limiting bolts 15 can be set and adjusted accordingly according to actual limiting requirements, for example, set to two at intervals.

[0053] Secondly, in this embodiment, as a preferred implementation form, the adjustment block 8 is located between the top wall 11 and the tooth portion of the gear shaft 2, and a first gasket is sandwiched between the adjustment block 8 and the top wall 11. In this way, the first gasket can avoid hard friction between the adjustment block 8 and the top wall 11 and play a role in alleviating vibration.

[0054] Furthermore, in this embodiment, as a preferred implementation form, Figure 1 As shown, the portion of the gear shaft 2 extending out of the top wall 11 is provided with a second gasket 9 and a retaining spring 100, and the second gasket 9 is fixed between the retaining spring 100 and the top wall 11. The second gasket 9 and the retaining spring 100 are used in combination to facilitate the disassembly and assembly of the second gasket 9 and alleviate vibration.

[0055] Moreover, the second gasket 9 and the retaining spring 100 of this embodiment can be directly sleeved on the gear shaft 2. Figure 4 As shown, in order to facilitate the installation convenience and stability of the retaining spring 100, a sixth groove 27 for installing the retaining spring 100 is further provided on the gear shaft 2.

[0056] In addition, in this embodiment, as a preferred implementation form, Figure 3 , Figure 5 and 8 As shown, the elastic component 33 is also provided on the side of the piston 31 away from the rack 32, the elastic component 33 is located between the piston 31 and the corresponding end cover 14, and the elastic component 33 includes a first sleeve 331 provided on the piston 31, a second sleeve 332 provided on the end cover 14, a guide rod 333 slidably provided in the first sleeve 331 and the second sleeve 332, and a spring 334 sleeved on the first sleeve 331, the guide rod 333 and the second sleeve 332. The main advantage of this arrangement is that it is not only simple in structure, but also highly stable.

[0057] Furthermore, in this embodiment, as a preferred implementation form, Figure 6 As shown, the piston 31 is provided with a first mounting groove 311, and the first sleeve 331 is arranged in the first mounting groove 311. In this embodiment, as a preferred implementation form, Figure 7 As shown, the end cover 14 is provided with a second mounting groove 141, and the second sleeve 332 is disposed in the second mounting groove 141. The use of the first mounting groove 311 and the second mounting groove 141 here can facilitate the assembly of the elastic component 33 and improve the stability in use.

[0058] In specific implementation, the elastic components 33 of this embodiment can be arranged in multiple intervals, and at the same time, the first installation groove 311 and the second installation groove 141 are adapted to the elastic components 33 to achieve a better installation effect. Moreover, when the elastic component 33 is applied to the rack and pinion pneumatic actuator of this embodiment, it can be used as a single-acting pneumatic actuator.

[0059] In addition, in this embodiment, as a preferred implementation form, continue to refer to Figure 4 As shown, the tooth portion of the gear shaft 2 includes a plurality of meshing teeth 23 arranged in sequence around the axial direction of the gear shaft 2, and a tooth groove 24 is formed between two adjacent meshing teeth 23. Limiting parts are respectively provided at both ends of the tooth groove 24, and each limiting part is used to limit each rack 32 from being separated from the tooth groove 24 in the axial direction of the gear shaft 2. The main benefit of providing the limiting part is that it can prevent each rack 32 from being separated from each tooth groove 24 and causing structural instability.

[0060] At the same time, in this embodiment, as a preferred implementation form, the limiting portion includes limiting protrusions arranged at both ends of the tooth groove 24, and a limiting inclined surface 25 is formed on the side of each limiting protrusion facing the tooth groove 24, and each limiting inclined surface 25 extends from the middle to the end along the axial direction of the gear shaft 2, and is arranged to be inclined outward along the radial direction of the gear shaft 2.

[0061] It is understandable that the limiting portion includes a limiting protrusion and a limiting inclined surface 25 , which can guide each rack 32 to reset when each rack 32 has a tendency to disengage from each tooth groove 24 , thereby preventing each rack 32 from disengaging from each tooth groove 24 .

[0062] It is worth mentioning that, in a specific implementation, the box body 1 of this embodiment also includes two oppositely arranged side walls 13 provided between the top wall 11 and the bottom wall 12, and two air ports 130 provided on one side wall 13 thereof, and the two air ports 130 are connected to an external high-pressure air source, etc.

[0063] At the same time, the gear shaft 2 of the present embodiment can be applied to both single-acting rack and pinion pneumatic actuators and double-acting rack and pinion pneumatic actuators. Specifically, when the elastic component 33 is not installed in the rack and pinion pneumatic actuator of the present embodiment, that is, the rack and pinion pneumatic actuator at this time can be used as a double-acting actuator. When one of its air ports 130 is intake air and the other air port 130 is exhaust air, the two pistons 31 move toward both ends under the action of the air source, drive the gear shaft 2 to rotate clockwise, and the actuator moves to the closed position (0°) (drive the valve stem of the valve to move to the closed position through the key slot 20), driving the valve to close; when the air inlet and outlet of the above-mentioned two air ports 130 are reversed, the two pistons 31 move toward the middle under the action of the air source, drive the gear shaft 2 to rotate counterclockwise, and the actuator moves to the open position (90°) (drive the valve stem of the valve to move to the open position through the key slot 20), driving the valve to open.

[0064] When the elastic component 33 is installed in the gear rack pneumatic actuator of this embodiment, the gear rack pneumatic actuator can be used as a single-acting actuator. When one of its air ports 130 is intake air and the other air port 130 is exhaust air, the two pistons 31 move toward both ends under the action of the air source, driving the gear shaft 2 to rotate clockwise, and the springs 334 in the two elastic components 33 are compressed, and the actuator moves to the closed position (0°), driving the valve to close; when one of the above-mentioned air ports 130 is exhaust air, each spring 334 extends and pushes the corresponding piston 31 to move toward the middle, driving the gear shaft 2 to rotate counterclockwise, and the actuator moves to the open position (90°), driving the valve to open.

[0065] The rack and pinion pneumatic actuator of this embodiment, by setting the first rotating part 21 and the second rotating part 22 to have the same diameter, can make the air pressure at both ends of the gear shaft 2 the same, so as to avoid the problem of the gear shaft 2 shaking along its own axis or even falling out of the box body 1 during rotation, thereby ensuring the overall operating stability of the equipment and having a good use effect.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A rack and pinion pneumatic actuator, characterized in that: It comprises a box body (1) with openings at both ends, a gear shaft (2) provided on the box body (1) so as to penetrate the box body (1) from top to bottom, two piston mechanisms (3) provided in the box body (1), and end covers (14) provided at both ends of the box body (1), wherein the end covers (14) block the openings corresponding thereto; The gear shaft (2) is rotatably mounted on the housing (1) and comprises a first rotating portion (21) and a second rotating portion (22) which are respectively rotatable relative to the top wall (11) and the bottom wall (12) of the housing (1), wherein the first rotating portion (21) and the second rotating portion (22) have the same diameter; In the length direction of the housing (1), the two piston mechanisms (3) are arranged on both sides of the gear shaft (2), and each piston mechanism (3) comprises a piston (31) slidably arranged in the housing (1), and a rack (32) arranged on the piston (31), and the rack (32) is meshed with the gear shaft (2).

2. The rack and pinion pneumatic actuator according to claim 1, characterized in that: The first rotating part (21) is sleeved with a first sealing ring (4) and a first bushing (5), and the first sealing ring (4) and the first bushing (5) are both sandwiched between the first rotating part (21) and the top wall (11); and / or, A second sealing ring (6) and a second bushing (7) are sleeved on the second rotating part (22); the second sealing ring (6) and the second bushing (7) are both sandwiched between the second rotating part (22) and the bottom wall (12).

3. The rack and pinion pneumatic actuator according to claim 2, characterized in that: The first rotating part (21) is provided with a first groove (211) and a second groove (212) which are arranged to extend axially around the gear shaft (2); the first sealing ring (4) is arranged in the first groove (211); and the first bushing (5) is arranged in the second groove (212); The second rotating part (22) is provided with a third groove (221) and a fourth groove (222) which are arranged to extend axially around the gear shaft (2); the second sealing ring (6) is arranged in the third groove (221); and the second bushing (7) is arranged in the fourth groove (222).

4. The rack and pinion pneumatic actuator according to claim 1, characterized in that: The gear shaft (2) is provided with an adjustment block (8), and the box body (1) is provided with a limit bolt (15) for limiting the rotation range of the adjustment block (8).

5. The rack and pinion pneumatic actuator according to claim 4, characterized in that: The adjustment block (8) is located between the top wall (11) and the tooth portion of the gear shaft (2), and a first gasket is sandwiched between the adjustment block (8) and the top wall (11).

6. The rack and pinion pneumatic actuator according to claim 4, characterized in that: A second gasket (9) and a retaining spring (100) are provided on the portion of the gear shaft (2) extending out of the top wall (11); the second gasket (9) is fixed between the retaining spring (100) and the top wall (11).

7. The rack and pinion pneumatic actuator according to claim 1, characterized in that: It also includes an elastic component (33) arranged on a side of the piston (31) away from the rack (32); The elastic component (33) is located between the piston (31) and the corresponding end cover (14), and comprises a first sleeve (331) provided on the piston (31), a second sleeve (332) provided on the end cover (14), a guide rod (333) slidably provided in the first sleeve (331) and the second sleeve (332), and a spring (334) sleeved on the first sleeve (331), the guide rod (333) and the second sleeve (332).

8. The rack and pinion pneumatic actuator according to claim 7, characterized in that: The piston (31) is provided with a first mounting groove (311), and the first sleeve (331) is arranged in the first mounting groove (311); and / or the end cover (14) is provided with a second mounting groove (141), and the second sleeve (332) is arranged in the second mounting groove (141).

9. The rack and pinion pneumatic actuator according to any one of claims 1 to 8, characterized in that: The toothed portion of the gear shaft (2) comprises a plurality of meshing teeth (23) arranged in sequence around the axial direction of the gear shaft (2), and a tooth groove (24) is formed between two adjacent meshing teeth (23); Limiting portions are respectively provided at both ends of the tooth groove (24), and each limiting portion is used to limit each rack (32) from disengaging from the tooth groove (24) in the axial direction of the gear shaft (2).

10. The rack and pinion pneumatic actuator according to claim 9, characterized in that: The limiting portion comprises limiting protrusions arranged at both ends of the tooth groove (24), and a limiting inclined surface (25) is formed on one side of each limiting protrusion facing the tooth groove (24), and each limiting inclined surface (25) extends from the middle to the end along the axial direction of the gear shaft (2) and is arranged to be inclined outward along the radial direction of the gear shaft (2).

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