Bellows cylinder
By using a cylinder with a bellows and spring structure, the problem that existing cylinders cannot simultaneously provide displacement and sealing in high-cleanliness environments has been solved, achieving linear drive and structural simplification for high-cleanliness environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LIAONING SEALTECH TECH CO LTD
- Filing Date
- 2025-07-07
- Publication Date
- 2026-05-29
AI Technical Summary
Existing cylinders cannot simultaneously provide displacement and sealing in high-cleanliness environments, and they also suffer from problems such as seal wear, particulate contamination, and complex structures.
The cylinder employs a bellows and spring structure, with the bellows serving as a sealing and displacement element, combined with the spring to provide reciprocating motion, replacing the traditional piston rod and dynamic sealing ring to achieve unidirectional gas movement.
It achieves linear drive in a high-cleanliness environment, eliminates the risk of wear particles and lubricant leakage, and has a simple structure and small size, making it suitable for equipment miniaturization.
Smart Images
Figure CN224301157U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of bellows technology, specifically relating to a bellows cylinder. Background Technology
[0002] Existing cylinders have limitations in sealing during operation. Traditional cylinders can only provide displacement and cannot achieve sealing. The internal channels and seals (such as piston seals and piston rod seals) of the cylinder body are complex, with a large number of parts. There are multiple sealing points between the piston and cylinder barrel, and between the piston rod and cylinder head. The piston wears down due to long-term reciprocating motion. Friction between the piston rod and the dynamic seals can generate metal particles or seal debris, contaminating the working medium, especially in vacuum and clean environments where requirements cannot be met. For example, in a cleanroom, the failure rate of traditional cylinders used for particulate contamination due to seal wear increased by 35%. Semiconductor manufacturing processes (such as photolithography, etching, thin film deposition, ion implantation, and cleaning) must be carried out in ultra-high cleanliness environments (Class 1 or lower), where even the smallest particulate contamination can lead to a significant decrease in chip yield. Therefore, existing cylinders cannot provide both displacement and a clean seal at the same time.
[0003] Welded bellows are a new type of component that emerged with the development of metal bellows processing and manufacturing technology and the expansion of its structural applications. Compared with traditional hydroformed metal bellows, it features high manufacturing precision, large displacement, large volume compensation, long service life, and a wide range of applicable materials. Therefore, it is widely used as a sealing element, isolation element, pressure sensing element, connecting element, and temperature compensator in the instrumentation industry, aerospace industry, electronics industry, and other industries. Using welded bellows for sealing, reciprocating, oscillating, and rotational motion can be transmitted into a vacuum. If it is degassed at high temperatures, it can transmit motion in high vacuum and even ultra-high vacuum systems. A welded bellows is a tubular shell with transverse corrugations formed by alternately welding multiple annular corrugated sheets stamped from thin plates along their inner and outer edges. The specific welding process is carried out in two steps: first, one upper and one lower corrugated sheet are paired together, and a circumferential seam is welded along the inner edge to form a component strung together; then, a circumferential seam is welded along the outer edge to form the welded bellows.
[0004] In the existing technology, the welded bellows used in the cylinder field are mostly bidirectional gas movement structures, which have disadvantages such as more complex structure, greater difficulty in manufacturing and assembly, difficulty in maintenance and troubleshooting, large volume space occupation, and possible lag in dynamic response. Utility Model Content
[0005] This utility model solves at least one of the above-mentioned technical problems by providing a bellows cylinder, including a first cylinder, a second cylinder, and a movable guide rod; the movable guide rod is disposed inside the first cylinder and the second cylinder; a spring retaining sleeve is disposed between the first cylinder and the second cylinder;
[0006] The first cylinder is provided with an air inlet, and a bellows is provided inside the first cylinder. A first flange and a second flange are provided at both ends of the bellows.
[0007] A spring is installed inside the second cylinder, one end of which is connected to a spring fixing sleeve, and the other end of which is provided with a spring base; a cylinder bottom cover is provided at one end of the second cylinder, the second cylinder is welded to the cylinder bottom cover, and a limiting plate is provided between the spring base and the cylinder bottom cover;
[0008] The first cylinder and the second cylinder are coaxial; a movable guide rod is provided on the axis of the first cylinder and the second cylinder; the movable guide rod is fixedly connected to the spring base.
[0009] Preferably, the movable guide rod includes a first movable rod, a flange, and a second movable rod connected in sequence; the flange is disposed inside the first cylinder.
[0010] Preferably, the first end of the bellows is welded to the first flange, and the last end of the bellows is welded to the second flange.
[0011] Preferably, the movable guide rod passes through the spring fixing sleeve, and a sliding bearing is provided between the movable guide rod and the spring fixing sleeve.
[0012] Preferably, the first flange is welded to the first cylinder.
[0013] Preferably, the maximum outer diameter of the bellows is smaller than the inner diameter of the first cylinder.
[0014] Preferably, the movable guide rod is fixedly connected to the spring base by screws, and a washer is provided between the screws and the spring base.
[0015] Preferably, it also includes a magnet and a sensor.
[0016] The beneficial effects of this utility model are:
[0017] When a traditional cylinder shaft is connected to a vacuum chamber, it can only provide displacement and cannot achieve sealing, especially the seal between the shaft and the chamber. This invention uses a bellows as a sealing and displacement element, and combines it with a spring to provide reciprocating motion, providing linear drive in a high-cleanliness environment.
[0018] This invention relates to a cylinder combining a bellows and a spring structure. Through a completely sealed structure using the bellows (which replaces the piston rod and dynamic sealing ring of a traditional cylinder), it completely eliminates the risks of metal or seal wear particles caused by friction during the reciprocating motion of the piston rod in existing technologies, as well as the risk of lubricant leakage. This invention features unidirectional gas movement, a simple structure, and a smaller overall size, facilitating miniaturization or compact layout of equipment. Attached Figure Description
[0019] Figure 1 This is a perspective view of a bellows cylinder according to this utility model.
[0020] Figure 2 This is a schematic diagram of the structure of a movable guide rod in a bellows cylinder according to this utility model.
[0021] Figure 3 This is a structural schematic diagram of a bellows cylinder according to the present invention.
[0022] Figure 4 This is a schematic diagram of the structure of a bellows cylinder in which the bellows is in a free state (stretched state).
[0023] Figure 5 This is a schematic diagram of the structure of a bellows cylinder in a compressed state according to the present invention.
[0024] In the diagram, the markings are as follows: 1 is bellows; 2 is first flange; 3 is moving guide rod; 4 is first cylinder; 5 is second cylinder; 6 is spring retaining sleeve; 7 is sliding bearing; 8 is spring; 9 is spring base; 10 is limiting plate; 11 is cylinder bottom cover; 12 is screw; 13 is washer; 14 is magnet; 15 is air inlet; 16 is second flange; 17 is first cavity; 18 is second cavity; 19 is sensor; 20 is ventilation channel; 21 is welding point; 301 is flange; 302 is first moving rod; 303 is second moving rod. Detailed Implementation
[0025] To make the technical problems solved, the technical solutions, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0026] Combination Figures 1 to 5 As shown, a bellows cylinder includes a first cylinder 4, a second cylinder 5, and a movable guide rod 3; the movable guide rod 3 is disposed inside the first cylinder 4 and the second cylinder 5; a spring fixing sleeve 6 is disposed between the first cylinder 4 and the second cylinder 5; the spring fixing sleeve 6 has a ventilation function, preferably, the spring fixing sleeve 6 is provided with a ventilation channel 20, and compressed gas entering from the air inlet 15 can enter the interior of the second cylinder 5 through the ventilation channel 20.
[0027] The first cylinder 4 is provided with an air inlet 15, and a bellows 1 is provided inside the first cylinder 4. The bellows 1 is a sealed structure and serves to isolate the vacuum. The bellows 1 is preferably a welded bellows.
[0028] The air inlet 15 is connected to the first cavity 17, but not to the bellows 1. The bellows 1 has a first flange 2 and a second flange 16 at both ends. Specifically, the first end of the bellows 1 is welded to the first flange 2, and the tail end of the bellows 1 is welded to the second flange 16. The bellows 1 is a sealed structure. Figure 5 Part of the welding point 21 is shown in the image.
[0029] A spring 8 is installed inside the second cylinder 5. One end of the spring 8 is connected to the spring fixing sleeve 6, and the other end of the spring 8 is provided with a spring base 9. A cylinder bottom cover 11 is provided at one end of the second cylinder 5. The second cylinder 5 is welded to the cylinder bottom cover 11. A limiting plate 10 is provided between the spring base 9 and the cylinder bottom cover 11. The setting of the limiting plate 10 restricts the movement range of the spring base 9, ensuring the stability and safety of the cylinder operation.
[0030] The first cylinder 4 and the second cylinder 5 are coaxial; a movable guide rod 3 is provided on the axis between the first cylinder 4 and the second cylinder 5; this arrangement ensures that the movable guide rod 3 moves smoothly and is fixedly connected to the spring base 9.
[0031] Specifically, the movable guide rod 3 includes a first movable rod 302, a flange 301, and a second movable rod 303 connected in sequence; the flange 301 is located inside the first cylinder 4. For example... Figure 4 As shown, when the bellows 1 is in a free state (stretched state), the first moving rod 302 is inside the first flange 2; as Figure 5 As shown, when the bellows 1 is in a compressed state, the first moving rod 302 extends out of the first flange 2.
[0032] The first cavity 17 is located between the first flange 2 and the flange 301, and the bellows 1 is disposed in the first cavity 17.
[0033] Specifically, the movable guide rod 3 passes through the spring retaining sleeve 6, and a sliding bearing 7 is provided between the movable guide rod 3 and the spring retaining sleeve 6. For example... Figure 3 As shown, the flange 301 is shaped to fit the spring retaining sleeve 6. The spring retaining sleeve 6 has a central hole through which the second moving rod 303 passes. A sliding bearing 7 is provided between the spring retaining sleeve 6 and the second moving rod 303. The sliding bearing 7 reduces the frictional resistance when the moving guide rod 3 moves, making the cylinder run more smoothly.
[0034] Specifically, the first flange 2 is welded to the first cylinder 4. Laser welding is preferred.
[0035] Specifically, the maximum outer diameter of the bellows 1 is smaller than the inner diameter of the first cylinder 4.
[0036] Specifically, the movable guide rod 3 is fixedly connected to the spring base 9 by screws 12, and a washer 13 is provided between the screws 12 and the spring base 9.
[0037] Specifically, it also includes a magnet 14 and a sensor 19. The magnet 14 is fixed to the movable guide rod 3 and moves with the movable guide rod 3. The sensor 19 is installed on the outside of the first cylinder 4. When the magnet 14 approaches the sensor 19, the change in magnetic field causes electrons inside the sensor 19 to migrate, generating a voltage signal. After processing by the amplification circuit, a pulse signal is output. The displacement of the magnet 14 inside the cylinder is reflected by the cooperation of the magnet 14 and the sensor 19. The rate of change of the displacement of the magnet 14 can also be monitored to determine whether the cylinder is stuck, or the spring 8 is malfunctioning.
[0038] The working process of this utility model:
[0039] like Figure 5 As shown, compressed gas is introduced through the air inlet 15 of the first cylinder 4, entering the first chamber 17 and then the second chamber 18 through the ventilation channel 20. The pressure inside the second chamber 18 is higher than the external atmospheric pressure. The moving guide rod 3 drives the spring base 9 to move towards the first chamber 17, forcing the spring 8 to compress. The bellows 1 is compressed under pressure, and the compressed gas enters the second chamber. Figure 5 In the compressed state, the guide rod 3 extends.
[0040] like Figure 4 As shown, when the compressed gas is discharged and the pressure inside the first chamber 17 and the second chamber 18 is the same as the external atmospheric pressure, the spring 8 pushes the spring base 9, which drives the moving guide rod 3. The moving guide rod 3 drives the second flange 16, which drives the bellows 1 to return to the free state or the stretched state.
[0041] This utility model is a cylinder that combines a bellows 1 and a spring 8. Through the completely sealed structure of the bellows 1 (the bellows 1 replaces the piston rod and dynamic sealing ring of the traditional cylinder), the risk of metal or seal wear particles caused by friction during the reciprocating motion of the piston rod in the prior art, as well as the risk of lubricating grease leakage, is completely eliminated.
[0042] Compared with unidirectional structures, bidirectional gas movement structures have disadvantages such as more complex structure, greater difficulty in manufacturing and assembly, more sealing points leading to easy leakage, high energy loss due to high gas flow resistance, difficulty in maintenance and troubleshooting, large volume space occupation, and potential lag in dynamic response. This utility model effectively avoids these problems by simplifying it into a unidirectional structure, achieving stable operation and structural simplification.
[0043] It is understood that the above specific description of this utility model is only used to illustrate this utility model and is not limited to the technical solutions described in the embodiments of this utility model. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to this utility model to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of this utility model.
Claims
1. A bellows cylinder, characterized in that: It includes a first cylinder (4), a second cylinder (5), and a movable guide rod (3); the movable guide rod (3) is disposed inside the first cylinder (4) and the second cylinder (5); a spring retaining sleeve (6) is disposed between the first cylinder (4) and the second cylinder (5); The first cylinder (4) is provided with an air inlet (15), and a bellows (1) is provided inside the first cylinder (4). The two ends of the bellows (1) are provided with a first flange (2) and a second flange (16). A spring (8) is provided inside the second cylinder (5). One end of the spring (8) is connected to the spring fixing sleeve (6), and the other end of the spring (8) is provided with a spring base (9). A cylinder bottom cover (11) is provided at one end of the second cylinder (5), and a limiting plate (10) is provided between the spring base (9) and the cylinder bottom cover (11). The first cylinder (4) and the second cylinder (5) are coaxial; a movable guide rod (3) is provided on the axis of the first cylinder (4) and the second cylinder (5); the movable guide rod (3) is fixedly connected to the spring base (9).
2. A bellows cylinder according to claim 1, characterized in that: The movable guide rod (3) includes a first movable rod (302), a flange (301), and a second movable rod (303) connected in sequence; the flange (301) is located inside the first cylinder (4).
3. A bellows cylinder according to claim 1, characterized in that: The first end of the bellows (1) is welded to the first flange (2), and the tail end of the bellows (1) is welded to the second flange (16).
4. A bellows cylinder according to claim 1, characterized in that: The movable guide rod (3) passes through the spring fixing sleeve (6), and a sliding bearing (7) is provided between the movable guide rod (3) and the spring fixing sleeve (6).
5. A bellows cylinder according to claim 1, characterized in that: The first flange (2) is welded to the first cylinder (4).
6. A bellows cylinder according to claim 1, characterized in that: The maximum outer diameter of the bellows (1) is smaller than the inner diameter of the first cylinder (4).
7. A bellows cylinder according to claim 1, characterized in that: The movable guide rod (3) is fixedly connected to the spring base (9) by screws (12), and a washer (13) is provided between the screws (12) and the spring base (9).
8. A bellows cylinder according to claim 1, characterized in that: It also includes a magnet (14) and a sensor (19).