A bellows fatigue life testing fixture

Abstract

This invention relates to the field of bellows testing fixture technology, specifically disclosing a bellows fatigue life testing fixture. Two testing mechanisms are mounted on the machine body. Each testing mechanism includes a chassis, a top plate, a drive rod, and a sealing cover. A first connecting seat and a second connecting seat are fixed to the chassis and top plate, respectively. An air intake hole is opened on the top plate and connected to an air extraction hose. The drive rod vertically penetrates the chassis and is fixed to a third connecting seat. The sealing cover can seal and connect with the chassis, and a through-connector connecting the air extraction hose to a vacuum generating system is fixed to its side wall. The two drive rods are connected by a synchronizing element; during reciprocating movement, one bellows extends while the other bellows retracts. This testing fixture can test bellows under normal pressure, external vacuum, and internal vacuum environments. It is suitable for welded bellows and ensures the accuracy of test data. Testing efficiency is significantly improved, operation is stable, energy consumption is low, and testing costs are greatly reduced. The structure is relatively simple, easy to manufacture, and has low implementation costs.

Description

Technical Field

[0001] This invention relates to the field of bellows testing fixtures, and more particularly to a bellows fatigue life testing fixture. Background Technology

[0002] Welded bellows, as a core component for high-precision sealing and motion transmission, are widely used in aerospace, vacuum equipment, and precision instruments. Their fatigue life directly affects equipment reliability, especially under vacuum conditions where welded bellows are subjected to cyclic pressure differences and deformation stresses, placing extremely stringent requirements on their fatigue performance. However, most existing fatigue testing equipment is only suitable for testing conventional bellows under normal pressure. When testing welded bellows, it is impossible to stably construct a vacuum environment on the inner or outer side, leading to significant deviations between test data and actual operating conditions.

[0003] The patent technology disclosed in CN119290563A provides a fatigue testing device for bellows under vacuum conditions, which can construct a vacuum environment to simulate the actual working conditions of welded bellows and improve the objectivity of test data. However, in actual implementation and use, there are still some shortcomings: for example, during the reciprocating expansion and contraction of the bellows, the load fluctuation of the drive unit is drastic, which adversely affects the system's operational stability, energy efficiency ratio, and energy consumption; during the test, the rebound force of the bellows and atmospheric pressure will generate reverse loads, and the device cannot effectively recover this energy, resulting in serious energy waste and further increasing energy consumption costs. In addition, the structural design of the air path and transparent cover in this technical solution is relatively complex, making it difficult to guarantee airtightness, resulting in high implementation costs and difficulties. Summary of the Invention

[0004] The technical objective of this invention is to provide a bellows fatigue life testing fixture to address the shortcomings of existing technologies.

[0005] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0006] A bellows fatigue life testing fixture includes a body and a testing mechanism; characterized in that the testing mechanism is provided in two sets, each set of the testing mechanism including:

[0007] The chassis and the top plate are fixed to the machine body, and the first connecting seat and the second connecting seat are fixed on opposite sides respectively; the chassis has a vent hole, and the top plate is connected to an air suction hose and has an air intake hole for connecting the inner cavity of the corrugated pipe to the air suction hose.

[0008] A drive rod that runs vertically through the chassis has a third connecting seat fixed on it, and the third connecting seat is located between the first connecting seat and the second connecting seat.

[0009] The sealing cover can be sealed to the chassis to seal the top plate and the third connecting seat inside it; a through joint is fixed to the side wall of the sealing cover, and the vacuum hose extends into the sealing cover and is connected to the vacuum generating system through the through joint.

[0010] The two drive rods are connected by a synchronizing element. After the bellows are installed in the same way in the two test mechanisms, during the reciprocating movement of the two drive rods, one bellows extends while the other bellows contracts, and so on.

[0011] In a preferred embodiment, the position of the third connecting seat on the drive rod is adjustable.

[0012] In a preferred embodiment, the first connecting seat and the second connecting seat are respectively detachably fixed to the chassis and the top plate, and the third connecting seat is detachably fixed to the drive rod.

[0013] In a preferred embodiment, when the drive rod passes through the vent hole through the chassis and both ends of the bellows are fixed to the first connecting seat and the third connecting seat respectively, the drive rod is located inside the bellows.

[0014] In a preferred embodiment, a plurality of vertically extending support columns are fixed on the chassis, and the top plate is supported and fixed by the support columns.

[0015] In a preferred embodiment, a vacuum detection device for detecting the internal vacuum level is connected to the through joint.

[0016] In a preferred embodiment, the synchronizing element is a gear transmission mechanism or a linkage mechanism, which is rotatably connected to the machine body, and the ends of the two drive rods away from the third connecting seat are connected via the gear transmission mechanism or linkage mechanism.

[0017] In a preferred embodiment, the synchronizing element is a fixed connector, and the ends of the two drive rods away from the third connecting seat are fixedly connected via the fixed connector.

[0018] In a preferred embodiment, the machine body includes a vertically extending frame; two testing mechanisms are supported by the frame, spaced apart vertically, and the axes of the two drive rods coincide; the ends of the two drive rods away from the third connecting seat are opposite each other and are fixedly connected by a synchronizing element; a driving device that is transmittedly connected to the synchronizing element is fixed inside the frame.

[0019] Furthermore, each of the two sealing covers is fixed on a sliding frame, and the frame is provided with a linear guide rail that cooperates with the sliding frame and a drive mechanism that is connected to the sliding frame.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] 1. It can perform fatigue life tests on bellows under normal pressure, external vacuum and internal vacuum environments, with strong applicability. In particular, it can meet the vacuum testing requirements of welded bellows, and improve the objectivity and accuracy of welded bellows test data.

[0022] 2. The two testing mechanisms work together, significantly improving testing efficiency; the load fluctuation during testing is small, the drive and transmission systems work stably and are highly energy efficient. In particular, the reverse load generated by the rebound force of the bellows and atmospheric pressure can be recovered and utilized, avoiding energy waste, significantly reducing the energy consumption of tooling operation, and saving testing costs.

[0023] 3. The overall structure is simple and reasonable. In particular, the air passage and sealing cover adopt an extremely simplified design, which makes it easy to ensure tightness. This makes the bellows fatigue life test fixture easy to manufacture and inexpensive to implement. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0025] Figure 1 This is a schematic diagram of the overall structure of the bellows fatigue life testing fixture in the embodiment.

[0026] Figure 2 This is a schematic diagram of the cooperation structure between the two testing mechanisms and the machine body in the embodiment.

[0027] Figure 3 This is a schematic diagram of the test mechanism in the embodiment.

[0028] Figure 4 This is a schematic diagram of the working state of the bellows fatigue life testing fixture in the normal pressure testing mode in the embodiment.

[0029] Figure 5 This is a schematic diagram of the working state of the bellows fatigue life testing fixture in the internal vacuum testing mode in the embodiment.

[0030] Figure 6 This is a schematic diagram of the working state of the bellows fatigue life testing fixture in the external vacuum testing mode in the embodiment.

[0031] Figure 7 This is a schematic diagram of the cooperation structure between the two test mechanisms and the machine body when the synchronization component is a linkage mechanism in the embodiment.

[0032] Figure 8 This is a schematic diagram of the cooperation structure between the two test mechanisms and the machine body when the synchronization component is a gear transmission mechanism in the embodiment.

[0033] In the diagram: 1. Body, 2. Sealing cover, 3. Vacuum hose, 4. Second connecting seat, 5. Synchronizing component, 6. Sealing gasket, 7. Drive rod, 8. Third connecting seat, 9. Stand, 10. First connecting seat, 11. Chassis, 12. Top plate, 13. Vacuum detection device, 14. Through joint, 15. Support column, 16. Vent hole, 17. Sliding frame, 18. Drive mechanism, 19. Linear guide rail, 20. Suction hole, 21. Drive device, 22. Vacuum generating system, 23. Linkage mechanism, 24. Gear transmission mechanism. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] See Figures 1-6 As shown in the embodiment, a bellows fatigue life testing fixture is disclosed, including a body 1, in which a drive device 21, a control system and two sets of testing mechanisms are installed; the testing mechanism includes a chassis 11, a top plate 12, a drive rod 7 and a sealing cover 2.

[0036] The chassis 11 and the top plate 12 are fixed to the body 1 and spaced apart. A first connecting seat 10 and a second connecting seat 4 are respectively installed and fixed on opposite sides of the chassis 11 and the top plate 12. The first connecting seat 10 and the second connecting seat 4 can be sealed to the end of the bellows. The chassis 11 has a vent 16 for communicating the inner cavity of the bellows with the atmosphere. The top plate 12 is connected to a suction hose 3 and has a suction hole 20 for communicating the inner cavity of the bellows with the suction hose 3.

[0037] The drive rod 7 is perpendicular to the chassis 11 and passes through the chassis 11. A third connecting seat 8 is fixed on the drive rod 7. The third connecting seat 8 can be sealed to the end of the bellows and block the end of the bellows. The third connecting seat 8 is located between the first connecting seat 10 and the second connecting seat 4. The three are distributed along the length of the drive rod 7.

[0038] The sealing cover 2 can be combined and separated from the chassis 11. The sealing cover 2 adopts a closed design, is cylindrical, and has an open end that can be sealed and connected with the chassis 11. To ensure sealing, a sealing gasket 6 can be installed on the mating surface of the sealing cover 2 and the chassis 11. When the sealing cover 2 is sealed and connected with the chassis 11, the top plate 12 and the third connecting seat 8 are sealed inside the sealing cover 2. A through joint 14 is sealed and fixed on the side wall of the sealing cover 2. The vacuum hose 3 extends into the sealing cover 2 and is connected to the vacuum generating system 22 through the through joint 14.

[0039] The two drive rods 7 in the two sets of testing mechanisms are connected by a synchronization element 5, thereby enabling the two drive rods 7 to transmit kinetic energy. The synchronization element 5 or one drive rod 7 is connected to the drive device 21, and the two drive rods 7 are driven by the drive device 21 to move synchronously. The synchronous movement only refers to the same stroke, movement speed, and reciprocating frequency, and does not mean that the movement direction of the two drive rods 7 must be the same. The control system can control the operating state of the drive device 21, and can set and adjust the position, movement speed, stroke, and reciprocating frequency of the two drive rods 7. After the corrugated pipes are installed and fixed in the same way in the two sets of testing mechanisms, the two drive rods 7 move synchronously back and forth during the operation of the fixture. When one corrugated pipe extends, the other corrugated pipe retracts, and so on alternately.

[0040] The working principle and testing method of this bellows fatigue life testing fixture are as follows:

[0041] Before testing, parameters such as the stroke, movement speed, and number of reciprocations of the drive rod are set according to the test requirements, and the corresponding test mode is selected, including atmospheric pressure test mode, internal vacuum test mode, and external vacuum test mode.

[0042] Atmospheric pressure test mode:

[0043] like Figure 4 As shown, the two bellows to be tested are fixed to the two test mechanisms in the same way; specifically, one end of the bellows is fixed to the first connecting seat 10 or the second connecting seat 4, which can be selected according to the convenience of operation, and the other end of the bellows is fixed to the third connecting seat 8; the test fixture is started and the two bellows alternately expand and contract in an atmospheric pressure environment until the test is completed or the termination condition is reached.

[0044] Internal vacuum test mode:

[0045] like Figure 3 , Figure 5As shown, the two bellows to be tested are respectively installed and fixed on the two test mechanisms; specifically, one end of the bellows is sealed and fixed on the second connecting seat 4, and the other end is sealed and fixed on the third connecting seat 8. At this time, the vacuum generating system 22 is connected to the inside of the bellows through the through joint 14, the suction hose 3 and the suction hole 20, which can evacuate the inside of the bellows to form an internal vacuum environment; the test fixture is started and the two bellows alternately expand and contract in the internal vacuum environment until the test is completed or the termination condition is reached.

[0046] External vacuum test mode:

[0047] like Figure 3 , Figure 6 As shown, two corrugated pipes to be tested are respectively installed and fixed on two testing mechanisms. Specifically, one end of the corrugated pipe is sealed and fixed to the first connecting seat 10, and the other end is sealed and fixed to the third connecting seat 8. The position of the sealing cover 2 is adjusted so that the open end of the sealing cover 2 is sealed and connected to the chassis 11. At this time, the sealing cover 2 and the corrugated pipe form a sealed interlayer space. The vacuum generating system 22 is connected to the interlayer space through the through joint 14, the suction hose 3 and the suction hole 20, which can evacuate the interlayer space to form an external vacuum environment. The inner cavity of the corrugated pipe is kept in contact with the atmosphere through the vent hole 16. The testing fixture is started and the two corrugated pipes alternately expand and contract in the external vacuum environment until the test is completed or the termination condition is reached.

[0048] This bellows fatigue life testing fixture offers the three testing modes mentioned above, enabling testing of bellows used in different working scenarios. It is particularly suitable for fatigue life testing of welded bellows, improving the objectivity and accuracy of test data.

[0049] This bellows fatigue life testing fixture adopts a dual-testing-mechanism design, enabling simultaneous testing of two bellows, significantly improving testing efficiency. Furthermore, it achieves remarkable technical improvements in operational stability and energy efficiency. The reasons for this are as follows:

[0050] See Figures 4-6 As shown, when the two testing mechanisms operate in tandem, one bellows extends while the other contracts, alternating in this manner. This results in smaller overall load fluctuations in the drive unit 21, enabling it to operate with a more constant output power, improving energy efficiency and operational stability, and effectively preventing increased wear on the transmission system caused by load fluctuations. Simultaneously, during testing, the rebound force of the bellows and atmospheric pressure generate reverse loads on the drive rods 7. The reverse load on one drive rod 7 can provide driving force for the other drive rod 7, achieving reverse load recovery and utilization, avoiding energy waste, significantly reducing the operating energy consumption of the drive unit 21, and saving testing costs.

[0051] In this bellows fatigue life testing fixture, the air path design is ingenious. The switching between internal and external vacuum testing modes is achieved through the installation method of the bellows. Vacuuming is performed using the same air path, eliminating the need for branch air paths and reversing devices. This significantly simplifies the air path, avoids the high failure rate caused by nodes and electronic control components, and makes the airtightness more stable. The sealing cover 2 has a simple structure, its tightness is easy to ensure, and its assembly and disassembly operations are convenient and quick. As a result, this bellows fatigue life testing fixture is easy to manufacture and has low implementation costs.

[0052] More specifically, the sealing cover 2 is made of transparent material to facilitate observation of the test conditions; the driving device 21 is selected from one of the following devices: linear motor with linear drive function, hydraulic cylinder, pneumatic cylinder, electric actuator, etc.

[0053] In this bellows fatigue life testing fixture, the suction hose 3 is positioned between the third connecting seat 8 and the sealing cover 2, ensuring that the suction port 20 is connected to the vacuum generating system 22 and that the position of the sealing cover 2 can be adjusted. When the sealing cover 2 is combined with the chassis 11, the suction hose 3 will be completely retracted into the sealing cover 2. To prevent the suction hose 3 from sagging and hindering the movement of the third connecting seat 8 or the expansion and contraction of the bellows, the suction hose 3 can be a spring-loaded telescopic hose. Alternatively, a spiral protective sleeve or drag chain or other auxiliary components can be installed on the outside of the suction hose 3 to guide the direction of the suction hose when it bends and avoid creating spatial obstacles with other components.

[0054] To further improve the applicability of the bellows fatigue life testing fixture to bellows, in a preferred embodiment:

[0055] The position of the third connecting seat 8 on the drive rod 7 is adjustable to accommodate bellows of different lengths and extension ranges. The specific mating structure between the third connecting seat 8 and the drive rod 7 can be implemented in various ways. For example, the third connecting seat 8 can be sleeved on the drive rod 7 with a sealed sliding fit, and a locking element can be provided to lock the third connecting seat 8 and the drive rod 7 in the pre-adjusted position. Other examples include... Figure 2 , Figure 3 As shown, the drive rod 7 is a telescopic rod, and the position of the third connecting seat 8 is adjusted by extending or retracting the drive rod 7;

[0056] like Figure 2 , Figure 3As shown, the first connecting seat 10 and the second connecting seat 4 are respectively detachably fixed to the chassis 11 and the top plate 12, and the third connecting seat 8 is detachably fixed to the drive rod 7. The detachable methods include common means such as bolt fixing and clamping. The first connecting seat 10, the second connecting seat 4 and the third connecting seat 8 have diverse designs, such as flange joints, threaded joints, quick joints or clamps that can seal and fix the ends of the bellows. When testing the bellows, the first connecting seat 10, the second connecting seat 4 and the third connecting seat 8 are replaced accordingly to adapt to the joint types at both ends of the bellows.

[0057] See Figure 6 As shown, in the external vacuum test mode, after the sealing cover 2 and the chassis 11 are combined, a sealed interlayer space should be formed between the sealing cover 2 and the bellows. The mating structure of the chassis 11 and the drive rod 7, as well as the supporting structure of the top plate 12, all need to consider their impact on the airtightness of the interlayer space; in the preferred embodiment:

[0058] like Figure 3 , Figure 6 As shown, when the drive rod 7 passes through the vent 16 and penetrates the chassis 11, and both ends of the bellows are fixed to the first connecting seat 10 and the third connecting seat 8 respectively, the drive rod 7 is located inside the bellows. This ensures that the fit clearance between the drive rod 7 and the chassis 11 is outside the interlayer space, thus eliminating the need for a sealed fit and facilitating implementation.

[0059] The chassis 11 is fixed with several vertically extending support columns 15, and the top plate 12 is supported and fixed by the support columns 15. Thus, when the sealing cover 2 is combined with the chassis 11, the top plate 12 and its support structure are located inside the sealing cover 2, so as not to affect the airtightness of the interlayer space. At the same time, the sealing cover 2 does not need to make space avoidance for the support structure of the top plate 12, so a more complete integrated structure can be adopted.

[0060] like Figure 3 As shown, in a preferred embodiment, a vacuum detection device 13 for detecting the internal vacuum level is connected to the through joint 14, such as a thermocouple vacuum gauge or an ionization vacuum gauge. Thus, the control system can determine whether the bellows is leaking based on the vacuum level data fed back by the vacuum detection device 13. Since both the external vacuum test mode and the internal vacuum test mode use the same gas path for vacuuming, the vacuum detection device 13 can play the expected role in both the external vacuum test mode and the internal vacuum test mode.

[0061] In this bellows fatigue life testing fixture, the function of the synchronizing element 5 is to connect the two drive rods 7 and ensure that the two drive rods 7 can drive the two bellows to alternately extend and retract. Depending on the installation method of the two testing mechanisms, the synchronizing element 5 can be implemented in various ways, specifically:

[0062] See Figure 7 , Figure 8 As shown, for example, when the drive rods 7 of both testing mechanisms are located in the vertical direction and the installation directions of the two testing mechanisms on the body 1 are consistent, the synchronizing element 5 can be a gear transmission mechanism 24 or a linkage mechanism 23 with a direction switching function; specifically, the gear transmission mechanism 24 is composed of a gear and a rack meshing, the gear is rotatably fixed on the body 1, and the rack is fixed to the end of the two drive rods 7 away from the third connecting seat 8, thereby enabling the two drive rods 7 to achieve a transmission connection; the linkage mechanism 23 includes a connecting rod, the connecting rod has a hinge point in the middle and is rotatably connected to the body 1, and the two ends of the connecting rod are movably connected to the end of the two drive rods 7 away from the third connecting seat 8; when the synchronizing element 5 adopts the above structure, when one drive rod 7 moves upward, the other drive rod 7 moves downward, thereby achieving the technical purpose of alternating extension and retraction of the two bellows;

[0063] See Figure 1 , Figure 2 As shown, for example, when the drive rods 7 of the two testing mechanisms are both located in the vertical direction and the installation directions of the two testing mechanisms on the body 1 are opposite, the synchronizing member 5 can be a fixed connecting member. The ends of the two drive rods 7 away from the third connecting seat 8 are fixedly connected by the fixed connecting member. Thus, the two drive rods 7 are driven to reciprocate in the same direction. Based on the opposite installation directions of the two testing mechanisms, the technical purpose of alternating expansion and contraction of the two bellows can be achieved.

[0064] See Figures 1-3 As shown, in a preferred embodiment, the body 1 includes a vertically extending frame 9, and the two test mechanisms are supported by the frame 9 respectively, distributed vertically at intervals, and the axes of the two drive rods 7 coincide; the ends of the two drive rods 7 away from the third connecting seat 8 are opposite to each other and are fixedly connected by a synchronizing member 5, which is preferably a coupling; the drive device 21 is fixed inside the frame 9 and is connected to the synchronizing member 5 in a transmission manner.

[0065] Furthermore, each of the two sealing covers 2 is fixed on a sliding frame 17. The upright frame 9 is provided with a linear guide rail 19 that cooperates with the sliding frame 17 and a drive mechanism 18 that is connected to the sliding frame 17. The drive mechanism 18 is used to adjust the position of the sealing cover 2 to realize the automatic operation of the combination and separation of the sealing cover 2. The drive mechanism 18 can be one of the following devices: a linear motor with linear drive function, a hydraulic cylinder, a pneumatic cylinder, an electric actuator, etc.

[0066] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

Claims

1. A bellows fatigue life testing fixture, comprising a body and a testing mechanism; characterized in that, The testing facility consists of two sets, each set including: The chassis and the top plate are fixed to the body, and the first connecting seat and the second connecting seat are fixed on opposite sides respectively. The chassis has a vent hole for connecting the inner cavity of the bellows to the atmosphere, and the top plate is connected to a suction hose and has a suction hole for connecting the inner cavity of the bellows to the suction hose. A drive rod that runs vertically through the chassis has a third connecting seat fixed on it, and the third connecting seat is located between the first connecting seat and the second connecting seat. The sealing cover can be sealed to the chassis to seal the top plate and the third connecting seat inside it; a through joint is fixed to the side wall of the sealing cover, and the vacuum hose extends into the sealing cover and is connected to the vacuum generating system through the through joint. The two drive rods are connected by a synchronous component. After the bellows are installed in the same way in the two test mechanisms, during the reciprocating movement of the two drive rods, one bellows extends while the other bellows contracts, and so on alternately. In the internal vacuum test mode, the two bellows are respectively installed and fixed on the two test mechanisms, and the two ends of the bellows are respectively sealed and fixed on the second connecting seat and the third connecting seat; in the external vacuum test mode, the two bellows are respectively installed and fixed on the two test mechanisms, and the two ends of the bellows are respectively sealed and fixed on the first connecting seat and the third connecting seat, and the opening end of the sealing cover is sealed and connected to the chassis.

2. The bellows fatigue life testing fixture according to claim 1, characterized in that: The position of the third connecting seat on the drive rod is adjustable.

3. The bellows fatigue life testing fixture according to claim 1, characterized in that: The first connecting seat and the second connecting seat are respectively detachably fixed to the chassis and the top plate, and the third connecting seat is detachably fixed to the drive rod.

4. The bellows fatigue life testing fixture according to claim 1, characterized in that: When the drive rod passes through the vent hole through the chassis and both ends of the bellows are fixed to the first connecting seat and the third connecting seat respectively, the drive rod is located inside the bellows.

5. The bellows fatigue life testing fixture according to claim 1, characterized in that: The chassis is fixed with several vertically extending support columns, and the top plate is supported and fixed by the support columns.

6. The bellows fatigue life testing fixture according to claim 1, characterized in that: A vacuum detection device for detecting the internal vacuum level is connected to the through joint.

7. The bellows fatigue life testing fixture according to claim 1, characterized in that: The synchronizing element is a gear transmission mechanism or a linkage mechanism, which is rotatably connected to the machine body. The ends of the two drive rods away from the third connecting seat are connected by the gear transmission mechanism or linkage mechanism.

8. The bellows fatigue life testing fixture according to claim 1, characterized in that: The synchronizing element is a fixed connector, and the ends of the two drive rods away from the third connecting seat are fixedly connected by the fixed connector.

9. The bellows fatigue life testing fixture according to claim 1, characterized in that: The machine body includes a vertically extending frame; two testing mechanisms are supported by the frame respectively, distributed vertically at intervals, and the axes of the two drive rods coincide; the ends of the two drive rods away from the third connecting seat are opposite each other and are fixedly connected by a synchronizing element; a drive device that is transmittedly connected to the synchronizing element is fixed inside the frame.

10. The bellows fatigue life testing fixture according to claim 9, characterized in that: Each of the two sealing covers is fixed on a sliding frame. The upright frame is equipped with a linear guide rail that cooperates with the sliding frame and a drive mechanism that is connected to the sliding frame.

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