External pressure pneumatic actuator for oil-forbidding corrugated pipe

Abstract

The utility model relates to the technical field of valves, in particular to an oil-forbidding corrugated pipe external pressure pneumatic actuator which comprises a shell and a valve, a double-layer corrugated pipe is arranged in the shell, a valve rod penetrates through the shell in a sliding mode, the valve rod penetrates through the corrugated pipe, guide sleeves used for preventing the valve rod from deviating are fixedly arranged at the two ends of the shell, and the valve rod penetrates through the double-layer corrugated pipe. A plurality of balls are rotationally embedded in the inner wall of the guide sleeve, the inner wall of the guide sleeve forms an inclined plane, the valve rod can be guided to move stably and linearly, deviation or shaking of the valve rod is effectively prevented, meanwhile, the balls make close contact with the side wall of the valve rod, friction abrasion is remarkably reduced, the surfaces of the valve rod and the guide sleeve are protected against damage, and the service life of the valve rod is prolonged. And the alloy ring is fixedly arranged in the shell, so that extra support and protection are provided for the corrugated pipe, the heat conduction effect is achieved in the high-temperature environment, the corrugated pipe is helped to dissipate heat, and the corrugated pipe is prevented from being damaged due to overheating.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and in particular to an oil-free bellows external pressure pneumatic actuator. Background Technology

[0002] Pneumatic actuators are commonly used drive devices in industrial automation and are widely used in various control systems, such as fluid control, process control, and mechanical automation. They use air pressure as a power source to drive actuators such as valve stems to perform linear or rotary motion, thereby realizing the opening, closing, or regulation of valves.

[0003] Chinese Patent CN221921996U discloses a valve that uses an integral locking element to seal the valve stem and bellows. The locking element seals the drive unit and valve body, and simultaneously locks the locking element and bellows to the valve body and the drive unit, simplifying the valve structure, reducing assembly steps, and improving sealing. Furthermore, this invention uses a rotating connector to automatically adjust the valve head during sealing, improving the sealing between the valve head and valve body and reducing or avoiding minor leaks caused by differences in sealing direction or angle. The stepped design at the threaded connection end of the locking element and valve body, along with the L-shaped pressure washer, improves valve reliability and extends valve life. However, problems arise when the valve stem shifts or wobbles during movement, or when the bellows is easily damaged, leading to inaccurate valve control and decreased performance of the pneumatic actuator. Therefore, this invention provides an oil-free bellows external pressure pneumatic actuator. Utility Model Content

[0004] The main objective of this invention is to provide an oil-free bellows external pressure pneumatic actuator to solve the problems mentioned in related technologies, such as inaccurate valve control and decreased performance of the pneumatic actuator when the valve stem deviates or wobbles during movement and the bellows is easily damaged.

[0005] To achieve the above objectives, according to one aspect of the present invention, an oil-free bellows external pressure pneumatic actuator is provided, comprising a housing and a valve. A double-layer bellows is provided inside the housing, and a valve stem is slidably disposed through the housing and passes through the bellows. Guide sleeves for preventing valve stem deviation are fixedly provided at both ends of the housing. A plurality of balls are rotatably embedded in the inner wall of the guide sleeves, and an alloy ring is fixedly disposed inside the housing.

[0006] Furthermore, the housing includes an upper shell and a lower shell, and screws are symmetrically threaded through one end of the upper shell and the lower shell. A connecting plate is fixedly connected to the other end of the lower shell, and one end of the lower shell is inserted into the valve.

[0007] Furthermore, a mounting block is provided at the connection between the upper shell and the lower shell, and an elastic layer is fixedly connected to the bottom of the mounting block, with a spring embedded in the elastic layer.

[0008] Furthermore, a first connecting block is fixedly connected to the upper end of the two corrugated pipes, the upper surface of the first connecting block is fixedly connected to the lower surface of the elastic layer, a second connecting block is fixedly connected to the lower end of the two corrugated pipes, and a flexible layer is fixedly connected between the two corrugated pipes.

[0009] Furthermore, the inner wall of one bellows is in close contact with the side wall of the valve stem, and the outer wall of the other bellows is in close contact with the inner wall of the alloy ring.

[0010] Furthermore, a limiting ring is fixedly connected to the outer wall of the valve stem, and the limiting ring is fixedly disposed within the second connecting block.

[0011] Furthermore, the diameter of the guide sleeve gradually decreases from one end to the other, and the ball at the bottom is in close contact with the side wall of the valve stem.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. In this oil-free bellows external pressure pneumatic actuator, the inner wall of the guide sleeve forms an inclined surface, which can guide the valve stem to move smoothly and linearly, effectively preventing the valve stem from deviating or shaking. At the same time, the close contact between the ball and the side wall of the valve stem significantly reduces friction and wear, protects the surface of the valve stem and the guide sleeve from damage, and enhances the stability of the valve stem within the guide sleeve.

[0014] 2. In this oil-free bellows external pressure pneumatic actuator, an elastic layer is provided at the upper end of the bellows, and a spring is embedded in the elastic layer, which significantly improves the rebound speed of the bellows, thereby accelerating the valve stem reset process. In addition, the alloy ring on the outside of the bellows not only provides additional support and protection for the bellows, but also plays a role in heat conduction in high-temperature environments, helping the bellows dissipate heat and preventing it from being damaged due to overheating, further improving the durability and safety of the actuator. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the oil-free bellows external pressure pneumatic actuator in a preferred embodiment of this utility model;

[0016] Figure 2 This is a preferred embodiment of the present invention. Figure 1 Enlarged schematic diagram of the structure at point A in the middle;

[0017] Figure 3 This is a preferred embodiment of the present invention. Figure 1 Enlarged schematic diagram of the structure at point B;

[0018] Figure 4 This is a preferred embodiment of the present invention. Figure 1 Enlarged schematic diagram of the structure at point C.

[0019] Illustration:

[0020] 1. Shell; 11. Upper shell; 12. Lower shell; 121. Connecting plate; 13. Screw;

[0021] 2. Corrugated pipe; 21. First connecting block; 22. Second connecting block; 23. Flexible layer;

[0022] 3. Valve stem; 31. Limit ring;

[0023] 4. Mounting block; 41. Elastic layer; 42. Spring;

[0024] 5. Alloy ring; 6. Guide sleeve; 61. Ball bearing; 7. Valve. Detailed Implementation

[0025] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0026] Please see Figures 1-4 As shown, the purpose of this embodiment is to provide an oil-free bellows external pressure pneumatic actuator, including a housing 1 and a valve 7. A double-layer bellows 2 is provided inside the housing 1, and a valve stem 3 is slidably arranged through the housing 1 and the valve stem 3 passes through the bellows 2. Guide sleeves 6 are fixedly provided at both ends of the housing 1 to prevent the valve stem 3 from deviating. A plurality of balls 61 are rotatably embedded in the inner wall of the guide sleeve 6, and an alloy ring 5 is fixedly provided inside the housing 1.

[0027] The housing 1 includes an upper shell 11 and a lower shell 12, and screws 13 are symmetrically threaded through one end of the upper shell 11 and the lower shell 12 to tightly fix the upper shell 11 and the lower shell 12 together. A connecting plate 121 is fixedly connected to the other end of the lower shell 12, and one end of the lower shell 12 is inserted into the valve 7. At this time, the connecting plate 121 is tightly fitted with the side wall of the valve 7. The connecting plate 121 has a mounting hole. By installing the bolt thread into the mounting hole, the connecting plate 121 and the valve 7 are fixedly connected, allowing a certain sealing effect to be formed between the housing 1 and the valve 7. In order to ensure the sealing performance, an O-ring is provided at the insertion point of the lower shell 12 and the valve 7.

[0028] An installation block 4 is provided at the connection between the upper shell 11 and the lower shell 12. In use, the installation block 4 needs to be installed in the predetermined position on the lower shell 12 first, and then the upper shell 11 is placed on top of the lower shell 12 to ensure that the alignment and positioning between them are accurate. The upper shell 11 and the lower shell 12 are fixed by tightening the screw 13 to form an integral shell 1. An elastic layer 41 is fixedly connected to the bottom of the installation block 4, and a spring 42 is embedded in the elastic layer 41.

[0029] The housing 1 is equipped with two layers of bellows 2. Compared to a single-layer bellows 2, its overall structural strength is significantly improved, allowing the bellows 2 to better withstand external pressure, including the internal air pressure during pneumatic actuator operation and potential external impacts or vibrations. The design of the double-layer bellows 2 also takes into account safety and reliability requirements. During the operation of the pneumatic actuator, if the single-layer bellows 2 is damaged or leaks for some reason, the double-layer bellows 2 can act as a second line of defense to prevent the medium from leaking into the external environment, thereby avoiding potential safety hazards and improving the overall safety and reliability of the pneumatic actuator.

[0030] The upper ends of the two corrugated pipes 2 are fixedly connected to a first connecting block 21, the upper surface of the first connecting block 21 is fixedly connected to the lower surface of the elastic layer 41, the lower ends of the two corrugated pipes 2 are fixedly connected to a second connecting block 22, and a flexible layer 23 is fixedly connected between the two corrugated pipes 2. The flexible layer 23 is preferably a silicone film. The silicone film has excellent flexibility, chemical corrosion resistance and high temperature stability, so it is very suitable as a connecting material between the corrugated pipes 2.

[0031] One of the bellows 2 has its inner wall in close contact with the side wall of the valve stem 3, and the other bellows 2 has its outer wall in close contact with the inner wall of the alloy ring 5. The alloy ring 5 not only provides additional support and protection, but in some cases, it can also play a role in heat conduction, helping the bellows 2 to dissipate heat. When the pneumatic actuator is working in a high-temperature environment, the bellows 2 may expand due to the heating of the internal medium. At this time, the alloy ring 5 can quickly conduct the heat on the bellows 2 to the surrounding environment, thereby preventing the bellows 2 from being damaged due to overheating.

[0032] A limiting ring 31 is fixedly connected to the outer wall of the valve stem 3, and the limiting ring 31 is fixedly set inside the second connecting block 22. When the valve stem 3 slides downward under the action of pneumatic pressure, the limiting ring 31 serves as the connection point between the valve stem 3 and the second connecting block 22. As the valve stem 3 slides down, the second connecting block 22 drives the bellows 2 to stretch downward. During this process, the corrugated structure of the bellows 2 gradually unfolds, and at the same time, the elastic layer 41 is also stretched. When the external pressure disappears, the bellows 2 begins to rebound due to its own elastic characteristics. At this time, the spring 42 in the elastic layer 41 begins to play a role, providing additional restoring force and accelerating the rebound process of the bellows 2. The elastic force of the spring 42 and the elasticity of the bellows 2 combine to enable the valve stem 3 to quickly and smoothly return to the initial position, thereby improving the dynamic response speed of the actuator.

[0033] The setting of spring 42 significantly improves the rebound speed of bellows 2, thereby speeding up the reset process of valve stem 3. This means that when the air pressure is released, the actuator can respond and return to the initial state more quickly, improving the dynamic performance and response speed of the entire system.

[0034] The guide sleeve 6 has a gradually decreasing diameter from one end to the other, forming a frustum-shaped annular structure. This special design creates an inclined surface on the inner wall of the guide sleeve 6. When the valve stem 3 moves axially under the action of aerodynamic force, the inclined surface of the guide sleeve 6 guides the valve stem 3 to move smoothly and linearly, effectively preventing the valve stem 3 from deviating or shaking. Furthermore, the ball bearing 61 located at the bottom is in close contact with the side wall of the valve stem 3, reducing frictional wear on the valve stem 3. The introduction of the ball bearing 61 significantly reduces frictional wear between the valve stem 3 and the guide sleeve 6. During the sliding process of the valve stem 3, the ball bearing 61 acts as an intermediary, bearing most of the frictional force, thus protecting the surfaces of the valve stem 3 and the guide sleeve 6 from damage. The close contact of the ball bearing 61 also enhances the stability of the valve stem 3 within the guide sleeve 6. Due to the rolling action of the ball bearing 61, the valve stem 3 can maintain a more stable movement trajectory during sliding, reducing additional friction and wear caused by shaking or deviating.

[0035] Furthermore, key components such as the bellows 2 are made of oil-free materials, ensuring that the entire actuator will not introduce grease contamination during use and meeting the requirements for oil-free media.

[0036] In practical use, one end of the lower shell 12 is inserted into the valve 7, and the lower shell 12 and the valve 7 are fixedly connected by the connecting plate 121. The mounting block 4 is installed in a predetermined position on the lower shell 12, and then the upper shell 11 is placed on top of the lower shell 12. The upper shell 11 and the lower shell 12 are fixedly connected by tightening the screw 13. When the valve stem 3 slides down under the action of pneumatic pressure, as the valve stem 3 slides down, the limiting ring 31 drives the second connecting block 22 to slide down. The second connecting block 22 then drives the bellows 2 to stretch down, and at the same time the elastic layer 41 is also stretched. When the external pressure disappears, the bellows 2 begins to rebound using its own elastic properties and the additional restoring force provided by the spring 42, so that the valve stem 3 quickly and smoothly returns to the initial position. During this process, due to the setting of the guide sleeve 6, the valve stem 3 is smoothly guided during the movement to prevent deviation or shaking.

[0037] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An oil-free bellows external pressure pneumatic actuator, comprising a housing (1) and a valve (7), wherein a double-layer bellows (2) is provided inside the housing (1), and a valve stem (3) is slidably disposed through the housing (1), and the valve stem (3) penetrates the bellows (2), characterized in that, Both ends of the housing (1) are fixedly provided with guide sleeves (6) to prevent the valve stem (3) from deflecting. Several balls (61) are rotatably embedded in the inner wall of the guide sleeve (6), and an alloy ring (5) is fixedly provided inside the housing (1).

2. The oil-free bellows external pressure pneumatic actuator according to claim 1, characterized in that, The housing (1) includes an upper shell (11) and a lower shell (12), and screws (13) are symmetrically threaded through one end of the upper shell (11) and the lower shell (12). A connecting plate (121) is fixedly connected to the other end of the lower shell (12), and one end of the lower shell (12) is inserted into the valve (7).

3. The oil-free bellows external pressure pneumatic actuator according to claim 2, characterized in that, An installation block (4) is provided at the connection between the upper shell (11) and the lower shell (12). An elastic layer (41) is fixedly connected to the bottom of the installation block (4), and a spring (42) is embedded in the elastic layer (41).

4. The oil-free bellows external pressure pneumatic actuator according to claim 3, characterized in that, The upper ends of the two corrugated pipes (2) are fixedly connected to a first connecting block (21), the upper surface of the first connecting block (21) is fixedly connected to the lower surface of the elastic layer (41), the lower ends of the two corrugated pipes (2) are fixedly connected to a second connecting block (22), and a flexible layer (23) is fixedly connected between the two corrugated pipes (2).

5. The oil-free bellows external pressure pneumatic actuator according to claim 1, characterized in that, The inner wall of one of the bellows (2) is in close contact with the side wall of the valve stem (3), and the outer wall of the other bellows (2) is in close contact with the inner wall of the alloy ring (5).

6. The oil-free bellows external pressure pneumatic actuator according to claim 4, characterized in that, The valve stem (3) is fixedly connected to a limiting ring (31) on its outer wall, and the limiting ring (31) is fixedly installed inside the second connecting block (22).

7. The oil-free bellows external pressure pneumatic actuator according to claim 1, characterized in that, The guide sleeve (6) has a gradually decreasing diameter from one end to the other, and the ball (61) at the bottom is in close contact with the side wall of the valve stem (3).

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