A middle-position limiting pneumatic actuator

Abstract

This utility model relates to the field of actuator technology, and in particular to a centrally positioned pneumatic actuator, comprising a cylinder body and a main shaft disposed inside the cylinder body. A piston is fitted on each side of the main shaft, and the piston drives the main shaft to rotate. The actuator also includes a positioning block, a first adjusting screw, and a second adjusting screw. A hexagonal post is disposed on the main shaft, passing through and connecting to the positioning block. The main shaft drives the positioning block to rotate coaxially via the hexagonal post. The first and second adjusting screws are threaded through the side wall of the cylinder body, and each end of the first and second adjusting screws inside the cylinder body has a first limiting end and a second limiting end, respectively. The first and second limiting ends are used to limit the contact with both ends of the positioning block. This utility model, with its centrally positioned limiting structure, allows for real-time adjustment of the actuator's stroke range.

Description

Technical Field

[0001] This utility model relates to the field of actuator technology, and in particular to a pneumatic actuator with a centrally located limit switch. Background Technology

[0002] A pneumatic actuator is an actuator that uses air pressure to open, close, or regulate a valve. It is also called a pneumatic actuator mechanism or pneumatic device, but it is commonly referred to as a pneumatic head. Pneumatic actuators are sometimes equipped with certain auxiliary devices, such as valve positioners and handwheel mechanisms. The function of a valve positioner is to use the feedback principle to improve the performance of the actuator, so that the actuator can achieve accurate positioning according to the control signal of the controller.

[0003] Although existing pneumatic actuators have a structure that limits the stroke, the limiting component for limiting the stroke is usually set inside the cylinder and cooperates with the piston. That is, the limiting component limits the piston, and in turn limits the rotation angle of the spindle that cooperates with the piston. This structure can only limit the stroke and cannot adjust the stroke according to real-time operating requirements.

[0004] The purpose of this invention is to propose corresponding solutions to the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a pneumatic actuator with a centrally located limit. This invention adopts a centrally located limit structure that allows for real-time adjustment of the actuator's stroke range.

[0006] The technical solution adopted by this utility model is as follows: A pneumatic actuator with a centrally located limit position includes a cylinder body and a main shaft disposed inside the cylinder body. A piston component is respectively fitted on both sides of the main shaft, and the piston component drives the main shaft to rotate. It also includes a positioning block, a first adjusting screw, and a second adjusting screw. A hexagonal column is provided on the main shaft. The hexagonal column passes through the positioning block and is connected to the positioning block. The main shaft drives the positioning block to rotate coaxially through the hexagonal column. The first adjusting screw and the second adjusting screw are both threaded through the side wall of the cylinder body. The ends of the first adjusting screw and the second adjusting screw that pass through the cylinder body are respectively provided with a first limiting end and a second limiting end. The first limiting end and the second limiting end are respectively used to limit the contact with the two ends of the positioning block.

[0007] The first and second adjusting screws are symmetrically arranged on both sides of the main shaft, and the positioning block is rhomboid in shape.

[0008] The inner wall of the positioning block is provided with at least one groove, and each groove is provided with a connecting component. The connecting component includes a connecting screw, one end of which is provided with a threaded section and the other end with a nut section. The threaded section is connected to the side wall of the hexagonal column by threads, and the nut section is located in the groove.

[0009] The connecting assembly also includes an elastic element sleeved on the threaded section, one end of which abuts against the nut section and the other end against the side wall of the hexagonal column.

[0010] The connecting assembly also includes an elastic sleeve that is fitted over the elastic element, and the elastic sleeve abuts against the inner wall of the groove.

[0011] The elastic sleeve is also abutted between the nut section and the hexagonal post. When the connecting screw is tightened toward the hexagonal post, the elastic sleeve is compressed by the nut section and deforms radially.

[0012] The elastic sleeve has at least two protruding rings on its outer periphery, and the two protruding rings are spaced apart.

[0013] The inner wall of each groove is conical, and the inner diameter of the end of the groove closest to the hexagonal prism is smaller than that of the end furthest from the hexagonal prism.

[0014] At least one positioning pin is provided between the positioning block and the hexagonal column, and the positioning pin is inserted into both the positioning block and the hexagonal column simultaneously, parallel to the axial direction of the hexagonal column.

[0015] The beneficial effects of this utility model are as follows: This utility model adopts a centrally located limiting structure, which can adjust the stroke range of the actuator in real time. Through the first adjusting screw and the second adjusting screw set on the side wall of the cylinder body, the positions of the first limiting end and the second limiting end extending into the cylinder can be precisely adjusted respectively. The two ends constitute the mechanical limiting points of the rotation arc of the positioning block, thereby directly determining the rotation angle of the main shaft. The adjusting screw can be conveniently rotated from the outside without disassembling the actuator, and the stroke range of the actuator can be adjusted in real time and online. This overcomes the technical defects of the fixed and unadjustable limiting structure, and greatly improves the adaptability of the equipment to different working conditions and the flexibility of control. The main shaft is sleeved with the positioning block through a hexagonal column and drives it to rotate coaxially. This non-circular cross-section matching method ensures that the torque transmission is free from slippage and backlash, and the transmission relationship is accurate and has good rigidity. As a direct limiting component, the positioning block avoids the cumulative error and hysteresis that may be caused by indirectly limiting the main shaft angle by limiting the piston movement in the traditional structure. This significantly improves the repeatability of the stroke termination position and the reliability of the action. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0017] Figure 1 This is a schematic diagram of the structure of a pneumatic actuator with a centrally located limit switch according to the present invention; Figure 2 This is a partial cross-sectional view of the present invention; Figure 3 This is a cross-sectional view of the positioning block in this utility model; Figure 4 for Figure 3 A magnified view of a portion of point A in the middle; Figure 5 This is a cross-sectional schematic diagram of another embodiment of the present utility model; In the figure, 1-cylinder body, 2-spindle, 3-piston, 4-locating block, 5-first adjusting screw, 6-second adjusting screw, 7-hexagonal column, 8-first limiting end, 9-second limiting end, 10-groove, 11-connecting screw, 12-threaded section, 13-nut section, 14-elastic element, 15-elastic sleeve, 16-convex ring, 17-locating pin. Detailed Implementation

[0018] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0019] It should be noted that all uses of "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this utility model. Subsequent embodiments will not explain this in detail.

[0020] The directional and positional terms used in this utility model, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0021] like Figures 1 to 4As shown, this is an embodiment of the present invention, a pneumatic actuator with a centrally located limit, including a cylinder body 1 and a main shaft 2 disposed inside the cylinder body 1. A piston 3 is respectively fitted on both sides of the main shaft 2, and the piston 3 drives the main shaft 2 to rotate. It also includes a positioning block 4, a first adjusting screw 5 and a second adjusting screw 6. A hexagonal column 7 is provided on the main shaft 2, and the hexagonal column 7 passes through and is connected to the positioning block 4. The main shaft 2 drives the positioning block 4 to rotate coaxially through the hexagonal column 7. The first adjusting screw 5 and the second adjusting screw 6 are both threaded through the side wall of the cylinder body 1, and the ends of the first adjusting screw 5 and the second adjusting screw 6 that pass through the cylinder body 1 are respectively provided with a first limiting end 8 and a second limiting end 9. The first limiting end 8 and the second limiting end 9 are respectively used to limit the abutment of the two ends of the positioning block 4.

[0022] The beneficial effects of this design are as follows: This invention employs a centrally located limiting structure, allowing for real-time adjustment of the actuator's stroke range. Through the first and second adjusting screws located on the side wall of the cylinder body, the positions of the first and second limiting ends extending into the cylinder can be precisely adjusted respectively. These two ends constitute the mechanical limiting points for the rotational arc of the positioning block, thereby directly determining the rotation angle of the main shaft. The adjusting screws can be conveniently rotated externally without disassembling the actuator, allowing for real-time, online adjustment of the actuator's stroke range. This overcomes the technical defects of fixed and unadjustable limiting structures, greatly improving the equipment's performance. The spindle offers adaptability to different working conditions and flexibility in control. It is connected to the positioning block via a hexagonal column and drives the positioning block to rotate coaxially. This non-circular cross-section connection ensures that torque transmission is free from slippage and backlash, resulting in precise transmission and good rigidity. The positioning block, as a direct limiting component, avoids the cumulative errors and hysteresis that may occur in traditional structures by indirectly limiting the spindle angle by limiting piston movement. This significantly improves the repeatability of the stroke termination position and the reliability of the action. The first and second adjusting screws can be controlled independently to adapt to various complex application requirements and enhance versatility.

[0023] Further configuration: the first adjusting screw 5 and the second adjusting screw 6 are symmetrically arranged on both sides of the main shaft 2, and the positioning block 4 is rhomboid in shape.

[0024] The beneficial effects of this design are as follows: the rhombus has two acute vertices, which are used to cooperate with the first and second limit ends respectively. This can effectively prevent the spindle from bearing additional radial load at the moment of limit, significantly improve the smoothness of the actuator's operation and structural reliability at the end of the stroke, extend the service life of the spindle and its seals, and has the advantages of simple structure and long positioning accuracy retention period.

[0025] Further, the inner wall of the positioning block 4 is provided with at least one groove 10, and each groove 10 is provided with a connecting component. The connecting component includes a connecting screw 11, one end of the connecting screw 11 is provided with a threaded section 12 and the other end is provided with a nut section 13. The threaded section 12 is connected to the side wall of the hexagonal column 7 by threads, and the nut section 13 is located in the groove 10.

[0026] The beneficial effects of this setup are as follows: by rigidly fastening the positioning block to the hexagonal column through the connecting screw, the gaps in the sleeve are eliminated, the connection is prevented from loosening, and the spindle torque is efficiently and without lag transmitted to the positioning block, making the limit action more immediate and accurate.

[0027] In a further configuration, the connecting assembly also includes an elastic element 14 sleeved on the threaded section 12, one end of which abuts against the nut section 13 and the other end of which abuts against the side wall of the hexagonal post 7.

[0028] The beneficial effects of this design are as follows: In this embodiment, the elastic element adopts a spring of existing technology, which provides a continuous and stable axial preload to the threaded section, eliminates thread gap, makes the threaded connection more secure, represents a qualitative leap from rigid relaxation to elastic relaxation, has stronger anti-loosening ability, and also has the advantages of impact resistance and vibration resistance.

[0029] In a further configuration, the connecting assembly also includes an elastic sleeve 15 that is sleeved outside the elastic member 14, and the elastic sleeve 15 abuts against the inner sidewall of the groove 10.

[0030] The beneficial effects of this design are as follows: the elastic sleeve can be made of materials such as silicone or rubber, making it deformable. The elastic sleeve fills the gap between the connecting screw and the side wall of the groove, ensuring that the positioning block can rotate synchronously when the main shaft rotates, and is used to bear the circumferential force to prevent wear on the connecting screw.

[0031] Furthermore, the elastic sleeve 15 is also abutted between the nut section 13 and the hexagonal post 7. When the connecting screw 11 is tightened toward the hexagonal post 7, the elastic sleeve 15 is compressed by the nut section 13 and deforms radially.

[0032] The beneficial effects of this design are as follows: the elastic sleeve can be pressed by the connecting screw and deformed radially, making the elastic sleeve more tightly abut against the inner wall of the groove, and bearing stronger and more uniform force.

[0033] Furthermore, the elastic sleeve 15 is provided with at least two protruding rings 16 on its outer periphery, and the two protruding rings 16 are spaced apart.

[0034] The beneficial effects of this design are as follows: when the elastic sleeve deforms, the two spaced convex rings increase the contact area, the elastic sleeve wall thickness increases, and it fits tightly against the inner wall of the groove more quickly.

[0035] Furthermore, the inner wall of each groove 10 is conical, and the inner diameter of the end of the groove 10 closest to the hexagonal prism 7 is smaller than that of the end furthest from the hexagonal prism 7.

[0036] The beneficial effects of this design are as follows: the inner wall of the groove is conical, which increases the space of the groove, facilitates assembly, and further prevents the positioning block from becoming loose from the hexagonal column.

[0037] like Figure 5 As shown, further, at least one positioning pin 17 is provided between the positioning block 4 and the hexagonal column 7, and the positioning pin 17 is inserted into the positioning block 4 and the hexagonal column 7 simultaneously, parallel to the axial direction of the hexagonal column 7.

[0038] The beneficial effects of this configuration are as follows: In another embodiment, the positioning pin is directly embedded between the positioning block and the hexagonal column, which increases the firmness of the connection between the positioning block and the hexagonal column. The positioning pin can be directly inserted along the axial direction, making assembly easier.

[0039] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A pneumatic actuator with a centrally located limit switch, comprising a cylinder body (1) and a main shaft (2) disposed inside the cylinder body (1), wherein a piston (3) is respectively fitted on both sides of the main shaft (2), and the piston (3) drives the main shaft (2) to rotate, characterized in that: It also includes a positioning block (4), a first adjusting screw (5) and a second adjusting screw (6). A hexagonal column (7) is provided on the main shaft (2). The hexagonal column (7) passes through the positioning block (4) and is connected to the positioning block (4). The main shaft (2) drives the positioning block (4) to rotate coaxially through the hexagonal column (7). The first adjusting screw (5) and the second adjusting screw (6) are both threaded through the side wall of the cylinder body (1). The first adjusting screw (5) and the second adjusting screw (6) are respectively provided with a first limiting end (8) and a second limiting end (9) at one end inside the cylinder body (1). The first limiting end (8) and the second limiting end (9) are respectively used to limit the contact between the two ends of the positioning block (4).

2. The pneumatic actuator with a centrally located limit switch according to claim 1, characterized in that: The first adjusting screw (5) and the second adjusting screw (6) are symmetrically arranged on both sides of the main shaft (2), and the positioning block (4) is rhomboid in shape.

3. A pneumatic actuator with a centrally located limit switch according to claim 1, characterized in that: The inner wall of the positioning block (4) is provided with at least one groove (10), and each groove (10) is provided with a connecting component. The connecting component includes a connecting screw (11), one end of the connecting screw (11) is provided with a threaded section (12) and the other end is provided with a nut section (13). The threaded section (12) is connected to the side wall of the hexagonal column (7) by threads, and the nut section (13) is located in the groove (10).

4. A pneumatic actuator with a centrally located limit switch according to claim 3, characterized in that: The connecting assembly also includes an elastic element (14) sleeved on the threaded section (12), one end of which abuts against the nut section (13) and the other end of which abuts against the side wall of the hexagonal column (7).

5. A pneumatic actuator with a centrally located limit switch according to claim 4, characterized in that: The connecting assembly also includes an elastic sleeve (15) that is sleeved outside the elastic member (14) and the elastic sleeve (15) abuts against the inner wall of the groove (10).

6. A pneumatic actuator with a centrally located limit switch according to claim 5, characterized in that: The elastic sleeve (15) is also abutted between the nut section (13) and the hexagonal column (7). When the connecting screw (11) is tightened toward the hexagonal column (7), the elastic sleeve (15) is compressed by the nut section (13) and deforms radially.

7. A pneumatic actuator with a centrally located limit switch according to claim 6, characterized in that: The elastic sleeve (15) has at least two protruding rings (16) on its outer periphery, and the two protruding rings (16) are spaced apart.

8. A pneumatic actuator with a centrally located limit switch according to claim 3, characterized in that: The inner wall of each groove (10) is conical, and the inner diameter of the end of the groove (10) near the hexagonal prism (7) is smaller than that of the end away from the hexagonal prism (7).

9. A pneumatic actuator with a centrally located limit switch according to claim 1, characterized in that: At least one positioning pin (17) is provided between the positioning block (4) and the hexagonal column (7), and the positioning pin (17) is inserted into the positioning block (4) and the hexagonal column (7) simultaneously in parallel with the axial direction of the hexagonal column (7).

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