Automobile hub air tightness detection device

Abstract

The utility model discloses an automobile hub air tightness detection device, which comprises a detection water tank, the interior of the detection water tank is divided into a first chamber and a second chamber through a partition plate, the bottom of the partition plate is provided with a water passing channel, and the first chamber and the second chamber are communicated through the water passing channel; the detection mechanism is arranged in the second cavity and comprises a clamping and sealing assembly used for clamping and sealing the hub and an inflation assembly used for inflating the closed space of the hub; the water level lifting mechanism is arranged in the first cavity and comprises a sliding plug and a lifting assembly, the side face of the sliding plug is in close contact with the inner wall of the first cavity, the lifting assembly is connected with the sliding plug, and the lifting assembly can push the sliding plug to be attached to the inner wall of the first cavity to descend and drive detection water below the sliding plug to flow towards the second cavity. Detection water is stored in the detection water tank and located below the sliding plug. The device is convenient to operate and detect water movement, the movement process is stable, trouble and labor are saved, and the electric power cost and the equipment cost are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile wheel hubs, in particular to an automobile wheel hub air tightness detection device. Background Art

[0002] During the casting process of the automobile wheel hub, sand holes may appear, and during the riveting process, gaps may easily appear, which are difficult to distinguish with the naked eye. If the air tightness test is not performed, the performance of the automobile wheel hub will not guarantee driving safety. Therefore, the air tightness of the wheel hub is an important indicator to measure the performance of the wheel hub and is of great significance.

[0003] The existing automobile wheel hub air tightness detection device adopts water immersion to detect, but during the detection process, multiple electric telescopic rods are required to drive the water tank to rise to submerge the wheel hub. The total mass of the water tank and the stored water used for detection is large. The electric telescopic rod needs to consume more electricity and energy costs in the process of driving the water tank to rise. The electric telescopic rod is easily damaged when working under high load for a long time, which increases the maintenance or replacement cost of the equipment. In addition, the water tank is unstable during the rising process, and the water in the water tank is easy to overflow due to shaking, affecting the operating environment. In addition, the existing automobile wheel hub air tightness detection device seals the wheel hub through a clamping plate and a fixing plate. The clamping plate and the fixing plate are provided with sealing rubber rings. During the detection, the sealing rubber ring is immersed in water. After the detection, the sealing rubber ring is exposed to the air. Long-term use causes the sealing rubber ring to age seriously. Since the sealing rubber ring is fixedly connected to the fixing plate and the clamping plate, the fixing plate and the clamping plate need to be replaced as a whole after the rubber ring ages, which increases the equipment cost. Utility Model Content

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide an automobile wheel hub air tightness detection device, which is convenient for controlling the detection water to submerge the wheel hub to be detected, has convenient and stable operation, and reduces electricity costs and equipment costs.

[0005] The utility model provides an automobile wheel hub air tightness detection device, which is characterized by comprising:

[0006] A detection water tank, wherein the top of the detection water tank is set to be an opening, and the interior of the detection water tank is divided into a first chamber and a second chamber by a partition, and a water passage is opened at the bottom of the partition, and the first chamber and the second chamber are connected through the water passage;

[0007] The detection mechanism is disposed in the second chamber and includes a clamping seal assembly for clamping the sealed wheel hub and an inflation assembly for inflating air into the closed space of the wheel hub;

[0008] The water level lifting mechanism is arranged in the first chamber, and includes a sliding plug and a lifting assembly. The side of the sliding plug is in close contact with the inner wall of the first chamber. The lifting assembly is connected to the sliding plug. The lifting assembly can push the sliding plug to fit the inner wall of the first chamber and descend, thereby driving the detection water under the sliding plug to flow to the second chamber.

[0009] Wherein, the detection water tank is located below the sliding plug and stores detection water.

[0010] Furthermore, the clamping and sealing assembly includes a placing table arranged at the bottom of the second chamber, a lower pressure plate is arranged on the top of the placing table, an upper pressure plate is arranged directly above the lower pressure plate, and the top of the upper pressure plate is connected to a first cylinder for driving the upper pressure plate to rise and fall; the inflation assembly includes an air pipe, one end of the air pipe passes through the upper pressure plate, and the other end is connected to an air pump.

[0011] Furthermore, the first cylinder is fixedly connected to the detection water tank through a first mounting frame, and the telescopic end of the first cylinder passes through the first mounting frame and is connected to the upper pressure plate;

[0012] The air pump is fixedly connected to the detection water tank via a second mounting frame.

[0013] Furthermore, the lifting assembly includes a third mounting frame and a second cylinder, the third mounting frame is arranged on the top of the detection water tank, and the telescopic end of the second cylinder passes through the third mounting frame and is connected to the sliding plug.

[0014] Furthermore, an upper fixing plate is detachably provided at the bottom of the upper pressing plate, an upper sealing rubber ring is fixedly connected to the bottom of the upper fixing plate, and one end of the air delivery pipe passes through the upper pressing plate and the upper fixing plate in sequence and extends to the inner side and lower side of the upper sealing rubber ring;

[0015] A lower fixing plate is detachably provided on the top of the lower pressing plate, and a lower sealing rubber ring is fixedly connected to the top of the lower fixing plate.

[0016] Furthermore, a plurality of auxiliary plates are evenly arranged on the top of the upper fixed plate along its circumference, and a first connecting member is hinged on the top of the auxiliary plate;

[0017] The upper pressure plate is provided with a plurality of auxiliary channels for the auxiliary plate to pass through, and the top of the upper pressure plate is evenly provided with a plurality of second connecting members matching the first connecting member along its circumference, and the first connecting member is fixedly connected with the second connecting member by bolts.

[0018] Furthermore, a plurality of slide grooves are evenly opened on the top of the upper pressure plate along its circumference, a slide rod is arranged in the slide groove, the second connecting member is slidably connected to the slide rod, a spring is sleeved on the slide rod, one end of the spring is fixedly connected to the inner wall of the slide groove, and the other end is fixedly connected to the second connecting member.

[0019] Compared with the prior art, the beneficial effects of the utility model are:

[0020] 1. The detection water tank of the utility model stores detection water below the sliding plug. When the automobile wheel hub is detected, the wheel hub is clamped by the sealing clamping assembly in the second chamber to form a sealed space inside the wheel hub. Subsequently, the sliding plug is driven downward by the lifting assembly to drive the detection water below it to flow into the second chamber through the water passage until the detection water submerges the wheel hub to be detected in the second chamber. Then, the closed space in the wheel hub is inflated by the inflation assembly, and whether the air tightness of the wheel hub meets the requirements is judged by observing whether there are bubbles on the water surface. The present application drives the detection water to move by the sliding plug, and the operation process is simple, which saves electricity costs. The lifting assembly drives the sliding plug to move up and down, and the sliding plug is light in weight, which causes less wear on the lifting assembly, reduces the maintenance and replacement costs of the equipment, and the detection water will not overflow during the movement process, and the detection process is more convenient and stable.

[0021] 2. The bottom of the upper pressure plate of the utility model is detachably connected to the upper fixing plate, the bottom of the upper fixing plate is provided with an upper sealing rubber ring, the top of the lower pressure plate is detachably provided with a lower fixing plate, and the top of the lower fixing plate is provided with a lower sealing rubber ring. The wheel hub is sealed by deformation of the upper sealing rubber ring and the lower sealing rubber ring, thereby improving the airtightness of the wheel hub and preventing air leakage during inflation, which affects the detection result. The upper fixing plate and the lower fixing plate can be used to conveniently remove the sealing rubber ring from the upper pressure plate and the lower pressure plate for replacement, thereby avoiding the need to replace the upper pressure plate or the lower pressure plate as a whole after the sealing rubber ring is aged, thereby reducing the replacement cost of the equipment.

[0022] It should be understood that the contents described in the utility model summary are not intended to limit the key or important features of the embodiments of the utility model, nor are they intended to limit the scope of the utility model. Other features of the utility model will become easy to understand through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0024] Figure 1 It is a schematic diagram of the structure of the utility model;

[0025] Figure 2 is a structural schematic diagram of the upper fixed plate;

[0026] Figure 3 Schematic diagram of the top view of the upper fixed plate;

[0027] Figure 4 It is a structural schematic diagram of the upper fixing plate and the upper pressing plate in the installed state;

[0028] Numbers in the figure: 1, detection water tank; 2, partition; 3, detection mechanism; 4, water level lifting mechanism; 5, auxiliary plate; 6, first connecting piece; 7, second connecting piece; 8, sliding rod; 9, spring;

[0029] 11. First chamber; 12. Second chamber;

[0030] 31. Clamping and sealing assembly; 32. Inflating assembly;

[0031] 41. Sliding plug; 42. Lifting assembly;

[0032] 311, placing table; 312, lower pressing plate; 313, upper pressing plate; 314, first cylinder; 315, upper fixing plate; 316, upper sealing rubber ring;

[0033] 321, gas pipeline; 322, air pump;

[0034] 421. Second cylinder. DETAILED DESCRIPTION

[0035] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It is also necessary to explain that, for the convenience of description, only the parts related to the utility model are shown in the accompanying drawings.

[0036] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] Please refer to Figure 1 The embodiment of the utility model provides an automobile wheel hub air tightness detection device, comprising a detection water tank 1, the upper part of the detection water tank 1 is set as an opening, the interior of the detection water tank is divided into a first chamber 11 and a second chamber 12 by a partition 2, a water passage is provided at the bottom of the partition 2, the first chamber 11 and the second chamber 12 are connected through the water passage, and detection water (clean water can be used as detection water) is stored in the detection water tank through a water pipe, and the detection water is located below the sliding plug 41;

[0038] The utility model also includes a detection mechanism 3 and a water level lifting mechanism 4, wherein the detection component 3 is arranged in the second chamber 12, including a clamping sealing component 31 for clamping the sealing hub and an inflation component 32 for inflating air into the closed space of the hub; the water level lifting mechanism 4 is arranged in the first chamber 11, including a sliding plug 41 and a lifting component 42, the side of the sliding plug 41 is in close contact with the inner wall of the first chamber 11, the lifting component 42 is connected to the sliding plug 41, and the lifting component 42 can push the sliding plug 41 to fit the inner wall of the first chamber 11 and descend, thereby driving the detection water below the sliding plug 41 to flow to the second chamber 12.

[0039] In this embodiment, before the detection begins, water is injected into the detection water tank 1 using a water pipe. After the injection, the sliding plug 41 is located above the water level, and the water levels in the first chamber 11 and the second chamber 12 are flush. At this time, the water level in the second chamber 12 is located below the clamping seal assembly 31, so as to prevent the detection water from submerging the detection seal assembly 31, resulting in water inside the wheel hub and affecting the detection structure.

[0040] During the inspection, the wheel hub to be inspected is placed on the clamping seal assembly 31, and the inner wall of the wheel hub is formed into a closed space through the inspection seal assembly 31. Then, the lifting assembly 42 is started to drive the sliding plug 41 to move downward, and the inspection water under the sliding plug 41 is pushed to flow to the second chamber 12 through the water passage. The water level in the first chamber 11 is reduced, and the water level in the second chamber 12 is increased until the inspection water in the second chamber 12 submerges the wheel hub to be inspected. Then, the inflation assembly 32 is started to inflate the closed space inside the wheel hub. If bubbles are generated on the water surface, the air tightness of the wheel hub does not meet the requirements. The present application uses the lifting assembly 42 and the sliding plug 41 to push the inspection water in the first chamber 11 to flow to the second chamber 12 until the water in the second chamber 12 submerges the wheel hub to be inspected. The equipment is simple and can save electricity costs. The lifting assembly 42 drives the light-weight sliding plug 41 to rise and fall, which can reduce the loss and reduce the equipment maintenance cost. The movement process of the inspection water is stable and will not overflow. The operation process is stable to avoid affecting the operating environment.

[0041] In a preferred embodiment, if Figure 1 As shown, the clamping and sealing assembly 31 includes a placing table 311 arranged at the bottom of the second chamber 12, a lower pressure plate 312 is arranged on the top of the placing table 311, an upper pressure plate 313 is arranged directly above the lower pressure plate 312, and the top of the upper pressure plate 313 is connected to a first cylinder 314 for driving the upper pressure plate 313 to rise and fall; the inflation assembly 32 includes an air pipe 321, one end of the air pipe 321 passes through the upper pressure plate 313, and the other end is connected to an air pump 322.

[0042] Preferably, the first cylinder 314 is fixedly connected to the detection water tank 1 through the first mounting frame, and the telescopic end of the first cylinder 314 passes through the first mounting frame and is connected to the upper pressing plate 313;

[0043] The air pump 322 is fixedly connected to the detection water tank 1 through a second mounting frame.

[0044] In this embodiment, a first mounting frame and a second mounting frame are fixedly arranged on the detection water tank 1, the first mounting frame extends to the inside of the second chamber 12, the first cylinder 314 is arranged on the first mounting frame in the vertical direction, and the telescopic end of the first cylinder 314 is fixedly connected to the upper pressing plate 313, the telescopic end of the first cylinder 314 can drive the upper pressing plate 313 to rise or fall, and the upper pressing plate 313 corresponds to the lower pressing plate 312; the second mounting frame is arranged on the outside of the detection water tank 1, and the air pump 322 is installed on the second mounting frame;

[0045] When inspecting the wheel hub, the wheel hub to be inspected is first placed on the lower pressure plate 312 on the top of the placement table 311, and then the first cylinder 314 is started. The telescopic end of the first cylinder 314 extends downward, driving the upper pressure plate 313 to move downward to squeeze the wheel hub to be inspected, and stably clamping the wheel hub while forming a closed space inside the wheel hub to be inspected. Then, the water in the second chamber 12 is submerged in the wheel hub to be inspected through the sliding plug 41, and then the air pump 322 is started, and air is inflated into the closed space of the wheel hub through the air supply pipe 321 connected to the air pump 322. Whether the air tightness of the wheel hub is qualified is judged by observing whether bubbles are generated on the water surface. The inspection process is simple and easy to operate. After the inspection is completed, the sliding plug 41 can be lifted upward to lower the water level in the second chamber 12, and the next wheel hub to be inspected can be placed. Then, the sliding plug 41 is pushed down again to raise the water level in the second chamber 12, and the next wheel hub is inspected. The operation is convenient and labor-saving.

[0046] In a preferred embodiment, if Figure 1 As shown, an upper fixing plate 315 is detachably provided at the bottom of the upper pressing plate 313, an upper sealing rubber ring 316 is fixedly connected to the bottom of the upper fixing plate 315, and one end of the air delivery pipe 321 passes through the upper pressing plate 313 and the upper fixing plate 315 in sequence and extends to the inner side and lower side of the upper sealing rubber ring 316;

[0047] A lower fixing plate is detachably provided on the top of the lower pressing plate 312, and a lower sealing rubber ring is fixedly connected to the top of the lower fixing plate.

[0048] In this embodiment, when the wheel hub is clamped, the wheel hub is placed on the lower sealing rubber ring 316, and the upper sealing rubber ring 316 and the lower sealing rubber ring cooperate with each other to press against the two ends of the automobile wheel hub, so that the inside of the automobile wheel hub is better sealed, avoiding air leakage inside the wheel hub during the inflation process, resulting in the inability to determine the leakage position of the wheel hub, affecting the detection results.

[0049] In a preferred embodiment, if Figure 2 to Figure 4As shown, a plurality of auxiliary plates 5 are evenly arranged on the top of the upper fixed plate 315 along its circumference, and a first connecting member 6 is hinged on the top of the auxiliary plate 5;

[0050] The upper pressing plate 313 is provided with a plurality of auxiliary channels for the auxiliary plates 5 to pass through. The top of the upper pressing plate 313 is evenly provided with a plurality of second connecting members 7 matching the first connecting members 6 along its circumference. The first connecting member 6 is fixedly connected to the second connecting member 7 by bolts.

[0051] In this embodiment, the upper fixed plate 315 is a cylindrical structure, the bottom of the upper fixed plate 315 is fixedly connected with an upper sealing rubber ring 316, and the top of the upper fixed plate 315 is evenly fixedly connected with four auxiliary plates 5 along its circumference. The provision of multiple auxiliary plates 5 can increase the stability of the connection between the fixed plate 315 and the upper pressure plate 313; the top of the auxiliary plate 5 is hinged with a first connecting member 6, and the top of the upper pressure plate 313 is provided with a second connecting member 7 corresponding to the first connecting member. The first connecting member 6 and the second connecting member 7 are penetrated by through holes, and the positions of the two through holes correspond to each other. The auxiliary channel on the upper pressure plate 313 corresponds to the auxiliary plate 5. After the auxiliary plate 5 passes through the auxiliary channel, the first connecting member 6 and the second connecting member 7 hinged on the top are fixed by bolts. The connection method between the lower fixed plate and the lower pressure plate 312 is the same as the connection method between the upper fixed plate 315 and the upper pressure plate 312, which will not be repeated here;

[0052] When the sealing rubber ring is aged, the bolts are removed, and the upper fixing plate 315 is removed from the upper pressure plate 313 to complete the replacement of the upper sealing rubber ring 316, thereby avoiding the need to replace the upper pressure plate 313 as a whole and reducing the replacement cost of the equipment.

[0053] In a preferred embodiment, if Figure 4 As shown, a plurality of slide grooves are evenly opened on the top of the upper pressure plate 313 along its circumference, a slide rod 8 is arranged in the slide groove, the second connecting member 7 is slidably connected to the slide rod 8, a spring 9 is sleeved on the slide rod 8, one end of the spring 9 is fixedly connected to the inner wall of the slide groove, and the other end is fixedly connected to the second connecting member 7.

[0054] In this embodiment, the number of slide grooves is the same as the number of second connecting members 7, which are set to four in this embodiment; the spring 9 is connected to the end of the second connecting member 7 away from the auxiliary channel. In the initial state, the spring 9 is in a normal state. When the auxiliary plate 5 is inserted into the auxiliary channel, the second connecting member 7 is pulled to move toward the end close to the auxiliary channel, and then the first connecting member 6 is rotated so that the first connecting member 6 is located on the side of the second connecting member 7 away from the auxiliary channel. Then, the spring is released to make the first connecting plate 6 and the second connecting plate 7 contact, and the first connecting plate 6 and the second connecting plate 7 are fixed by bolts; after the second connecting member 7 is connected to the first connecting member 6, the spring is in a stretched state. Under the action of the spring, the contact between the first connecting member 6 and the second connecting member 7 is closer, making the connection between the two more stable.

[0055] Working process:

[0056] When testing the automobile wheel hub, the automobile wheel hub to be tested is placed on the lower sealing rubber ring on the top of the lower pressure plate 312, and the upper pressure plate 313 is driven downward by the first cylinder 314 to make the upper sealing rubber ring 316 at the bottom of the upper pressure plate 313 contact the end face of the wheel hub. The upper sealing rubber ring 316 and the lower sealing rubber ring are deformed to form a closed space inside the automobile wheel hub to avoid a large amount of air leakage inside the wheel hub during inflation, which affects the test result. After the wheel hub is sealed, the second cylinder 421 is started, and the second cylinder 421 drives the sliding plug 41 to move downward. The sliding plug 41 pushes the test water below it to flow into the second chamber 12 through the water passage, the water level in the first chamber 11 drops, and the water level in the second chamber 12 rises until the wheel hub to be tested is submerged. The test water is driven to move by the sliding plug 41, which is simple to operate, saves trouble and labor, and saves electricity costs. In addition, the test water is stable and will not overflow during the movement, and does not affect the operating environment. Then start the air pump 322, and the air pump 322 inflates the inside of the wheel hub through the air pipe 321. By observing whether bubbles are generated on the water surface, it is judged whether the air tightness of the wheel hub meets the requirements.

[0057] In the description of this specification, the terms "connection", "installation", "fixation" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] In the description of this specification, the description of the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0059] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automobile wheel hub air tightness detection device, characterized in that: include: A detection water tank (1), wherein the top of the detection water tank (1) is arranged to be open, and the interior of the detection water tank (1) is divided into a first chamber (11) and a second chamber (12) by a partition (2), and a water passage is provided at the bottom of the partition (2), and the first chamber (11) and the second chamber (12) are connected via the water passage; A detection mechanism (3) is arranged in the second chamber (12), comprising a clamping seal assembly (31) for clamping the sealed wheel hub and an inflation assembly (32) for inflating air into the closed space of the wheel hub; The water level lifting mechanism (4) is arranged in the first chamber (11), and comprises a sliding plug (41) and a lifting assembly (42). The side surface of the sliding plug (41) is in close contact with the inner wall of the first chamber (11). The lifting assembly (42) is connected to the sliding plug (41). The lifting assembly (42) can push the sliding plug (41) to fit the inner wall of the first chamber (11) and descend, thereby driving the detection water below the sliding plug (41) to flow toward the second chamber (12). The detection water tank (1) is located below the sliding plug (41) and stores detection water.

2. The automobile wheel hub air tightness detection device according to claim 1, characterized in that: The clamping sealing component (31) includes a placing platform (311) arranged at the bottom of the second chamber (12), a lower pressure plate (312) is arranged on the top of the placing platform (311), an upper pressure plate (313) is arranged directly above the lower pressure plate (312), and the top of the upper pressure plate (313) is connected to a first cylinder (314) for driving the upper pressure plate (313) to rise and fall; the inflation component (32) includes an air supply pipe (321), one end of the air supply pipe (321) passes through the upper pressure plate (313), and the other end is connected to an air pump (322).

3. The automobile wheel hub air tightness detection device according to claim 2, characterized in that: The first cylinder (314) is fixedly connected to the detection water tank (1) via a first mounting frame, and the telescopic end of the first cylinder (314) passes through the first mounting frame and is connected to the upper pressing plate (313); The air pump (322) is fixedly connected to the detection water tank (1) via a second mounting frame.

4. The automobile wheel hub air tightness detection device according to claim 1, characterized in that: The lifting assembly (42) comprises a third mounting frame and a second cylinder (421), wherein the third mounting frame is arranged on the top of the detection water tank (1), and the telescopic end of the second cylinder (421) passes through the third mounting frame and is connected to the sliding plug (41).

5. The automobile wheel hub air tightness detection device according to claim 2, characterized in that: An upper fixing plate (315) is detachably provided at the bottom of the upper pressing plate (313), an upper sealing rubber ring (316) is fixedly connected to the bottom of the upper fixing plate (315), and one end of the air delivery pipe (321) passes through the upper pressing plate (313) and the upper fixing plate (315) in sequence and extends to the inner side and lower side of the upper sealing rubber ring (316); A lower fixing plate is detachably provided on the top of the lower pressing plate (312), and a lower sealing rubber ring is fixedly connected to the top of the lower fixing plate.

6. The automobile wheel hub air tightness detection device according to claim 5, characterized in that: A plurality of auxiliary plates (5) are evenly arranged on the top of the upper fixed plate (315) along its circumference, and a first connecting member (6) is hingedly connected to the top of the auxiliary plate (5); The upper pressure plate (313) is provided with a plurality of auxiliary channels for the auxiliary plate (5) to pass through, and a plurality of second connecting members (7) matching the first connecting member (6) are evenly arranged on the top of the upper pressure plate (313) along its circumference, and the first connecting member (6) and the second connecting member (7) are fixedly connected by bolts.

7. The automobile wheel hub air tightness detection device according to claim 6, characterized in that: The top of the upper pressure plate (313) is evenly provided with a plurality of slide grooves along its circumference, a slide rod (8) is arranged in the slide groove, the second connecting member (7) is slidably connected to the slide rod (8), a spring (9) is sleeved on the slide rod (8), one end of the spring (9) is fixedly connected to the inner wall of the slide groove, and the other end is fixedly connected to the second connecting member (7).

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