Rotary shaft structure for polishing machine

Abstract

To provide a rotary shaft structure for a polishing machine that enables easily replacing polishing bars, facilitating user operation, and enhancing user experience.SOLUTION: A rotary shaft structure for a polishing machine comprises a shaft rod and a shaft sleeve, and further comprises a shaft case, a first clamping member, a second clamping member, and a third clamping member. One end of the shaft rod is connected to the shaft sleeve, and the other end of the shaft rod is connected to the third clamping member. The third clamping member has a clamping opening at the end opposite to the shaft rod, the opening being openable and closable. The first clamping member is a hollow circular tube, within which both the second clamping member and the third clamping member are located, with the second clamping member located on a side away from the shaft rod of the third clamping member. An end of the second clamping member is fitted into the clamping opening of the third clamping member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of grinding machines, and particularly to a rotating shaft structure for grinding machines. [Background technology]

[0002] As people's living standards improve, handheld nail polishers have become a popular household appliance among women and pet lovers. Handheld nail polishers are divided into two types: wired and wireless, with wireless nail polishers being powered by a storage battery. The main structure of a nail polisher includes a housing, a power supply module, a control module, a brushless motor, a rotating shaft structure, and a polishing rod. Its operating principle is that the polishing rod is connected to the rotating shaft structure, the rotating shaft structure is connected to the brushless motor, the power supply module supplies power to the brushless motor, the control module controls the start / stop and rotation speed of the brushless motor, and the brushless motor drives the rotating shaft structure and the polishing rod to rotate, thereby achieving the polishing function.

[0003] The polishing rod needs to be replaced constantly, mainly because the polishing rod wears out with use, reducing the polishing effect, and polishing rods with different structures and specifications have different application ranges. In order to easily replace the polishing rod, facilitate user operation, and improve the user experience, the applicant proposes a rotating shaft structure for a polishing machine that allows the polishing rod to be easily replaced. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating shaft structure for a grinding machine, which can easily replace a grinding rod, facilitate user operation, and improve the user's experience. [Means for solving the problem]

[0005] The present invention is realized as follows: A rotating shaft structure for a grinding machine, comprising a shaft rod and a shaft sleeve, and further comprising a shaft case, a first clamping member, a second clamping member, and a third clamping member, one end of the shaft rod is connected to the shaft sleeve, the other end of the shaft rod is connected to the third clamping member, the third clamping member has an openable and closable clamping opening at an end remote from the shaft rod, the first clamping member is a hollow round tube, the second clamping member and the third clamping member are both located within the first clamping member, and the second clamping member is located on the side of the third clamping member remote from the shaft rod, and an end of the second clamping member is connected to the third clamping member. a first spring is fitted to the clamping opening of a material, the first clamping member and the third clamping member are connected so as to be slidable back and forth; a first spring is fitted to the third clamping member; the third clamping member includes a second round tube portion installed on the outer wall of the third clamping member; one end of the first spring is in elastic contact with the second round tube portion and the other end of the first spring is in elastic contact with the second clamping member; the first spring is abutted against the second clamping member by the second round tube portion on the third clamping member; the inner wall of the second clamping member pushes out the clamping opening of the third clamping member, causing the clamping opening on the third clamping member to contract and be in a clamped state.

[0006] Furthermore, a first round tube portion is installed at one end of the axial rod, one end of the third clamping member is inserted into the first round tube portion and rotates synchronously with the first round tube portion, the third clamping member further includes a third round tube portion, the end of the third round tube portion facing the first round tube portion is a clamping opening, and a plurality of opening / closing slits are installed in the circumferential direction on the tube wall of the clamping opening.

[0007] Furthermore, a protrusion structure is provided on the outer wall of the clamping opening of the third circular tube portion, the second clamping member is a hollow circular tube, one end of the second clamping member extends to the outside of the first clamping member, and the end of the second clamping member fitted into the clamping opening has a fitting opening with a gradually decreasing diameter.

[0008] Furthermore, the first clamping member includes a first mounting round tube portion and a second mounting round tube portion. The aperture diameter of the first mounting round tube portion is larger than that of the second mounting round tube portion. Both the second round tube portion and the third round tube portion of the third clamping member are completely located within the first mounting round tube portion. The outer diameter of the second round tube portion is larger than the aperture diameter of the second mounting round tube portion. The length of the second round tube portion is L1, and the distance from the second round tube portion to the protruding structure is L2. The first clamping member is fixedly connected to the second clamping member, and the second clamping member is installed within the first mounting round tube portion of the first clamping member. The distance between the second clamping member and the second mounting round tube portion is L3, and L3 satisfies the formula L3 < L1 + L2.

[0009] Furthermore, two bearings are installed within the shaft case. The first clamping member is installed within the two bearings, and both ends of the first clamping member penetrate through both ends of the shaft case. A positioning ring and a second spring are further installed within the shaft case. Both the positioning ring and the second spring are sleeved on the first clamping member. The second spring is clamped between the positioning ring and the bearing approaching the shaft rod. The end of the shaft case near the shaft rod is open and installed, and a threaded structure is installed on the inner wall of this end. An axial cover is attached to the threaded structure by a screw. A through hole through which the first clamping member penetrates is installed at the center of the axial cover

[0010] Furthermore, a through hole through which the first clamping member penetrates is installed at the end of the shaft case away from the shaft rod, and a first annular concave groove is installed on the outer cylindrical wall of this end. A first rubber ring is installed in the first annular concave groove. A second annular concave groove is installed on the outer cylindrical wall of the axial cover, and a second rubber ring is installed in the second annular concave groove.

[0011] Furthermore, a limiting push platform is sleeved on the outer wall of the end of the first clamping member away from the shaft rod. The limiting push platform is annular, and the outer diameter of the limiting push platform is larger than the aperture diameter of the through hole through which the first clamping member installed on the shaft case penetrates.

[0012] Furthermore, a limiting sleeve case is further installed within the shaft case, the limiting sleeve case having a circular structure, the outer diameter of the limiting sleeve case being the same as the hole diameter of the shaft case, the limiting sleeve case being positioned between the two bearings, and both ends of the limiting sleeve case respectively contacting the outer rings of the two bearings.

[0013] Furthermore, a stroke chamber and a non-circular connecting through-hole are provided in the shaft sleeve, an insertion rod portion that fits into the non-circular connecting through-hole is provided at the end of the shaft rod connected to the shaft sleeve, and the insertion rod portion of the shaft rod passes through the stroke chamber and is inserted into the non-circular connecting through-hole of the shaft sleeve.

[0014] Furthermore, a limiting member is fixedly installed on the axial rod, and the limiting member is located near the center of the axial rod. A third annular groove is formed at the end of the axial rod body near the insertion rod portion, and a third rubber ring is installed in the third annular groove. A fourth annular groove is formed on the inner wall of the end of the axial sleeve away from the axial rod, and a fourth rubber ring is installed in the fourth annular groove. [Effects of the Invention]

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] First, the rotating shaft structure for a grinding machine according to the present invention allows for easy replacement of the grinding rod during use, facilitating user operation and improving the user experience.

[0017] Secondly, the rotating shaft structure for a grinding machine according to the present invention has a shaft sleeve installed, which makes the connection between the shaft rod and the motor of the grinding machine more stable, making it easier to assemble, and also has the advantage of reducing vibration, improving the operational stability of the grinding machine and reducing operational noise. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of the three-dimensional structure according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the overall structure according to the present invention. [Figure 3] FIG. 3 is a diagram showing a separated state of the first clamping member, the second clamping member, and the third clamping member according to the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing the first clamping member, the second clamping member, and the third clamping member according to the present invention clamping a polishing rod. [Figure 5] FIG. 5 is a view showing a state in which the first clamping member, the second clamping member, and the third clamping member according to the present invention are separated from the shaft rod and the shaft sleeve. [Figure 6] FIG. 6 is a schematic diagram of the internal structure of the shaft case according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] In the present invention, unless otherwise clearly defined and limited, the terms "attached," "coupled," "connected," "fixed," etc. should be understood in a broad sense, and may mean, for example, a fixed connection, a detachable connection, or an integral unit, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate element, internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0020] The present invention will be further explained below with reference to specific examples and drawings.

[0021] As shown in FIGS. 1 to 6 , this rotating shaft structure for a grinding machine includes a shaft rod 1, a shaft sleeve 2, a shaft case 3, a first clamping member 4, a second clamping member 5, and a third clamping member 6. The shaft sleeve 2 connects the motor shaft and the shaft rod 1. A stroke chamber 201 and a non-circular connecting through-hole 202 are provided in the shaft sleeve 2, and the stroke chamber 201 is located at the end connected to the shaft rod 1. The non-circular connecting through-hole 202 may be cross-shaped, triangular, regular hexagonal, splined, or the like. An insertion rod portion 101 that fits into the non-circular connecting through-hole is provided at the end of the shaft rod 1 that connects to the shaft sleeve 2. The insertion rod portion 101 of the shaft rod 1 passes through the stroke chamber 201 and is inserted into the non-circular connecting through-hole 202 of the shaft sleeve 2, thereby realizing synchronous rotation of the shaft rod 1 and the shaft sleeve 2. A limiting member 15 is fixedly provided on the shaft rod 1 and is located near the center of the shaft rod 1. The stroke chamber 201 and the limiting member 15 provide a certain amount of space for the axial sleeve 2 and the axial rod 1 to move axially relative to each other, thereby serving to dampen vibration. The axial rod body is located between the inserted rod part 101 and the limiting member 15. A third annular groove is located at the end of the axial rod body closer to the inserted rod part 101, and a third rubber ring 16 is installed in the third annular groove. A fourth annular groove is located on the inner wall of the end of the axial sleeve 2 away from the axial rod 1, and a fourth rubber ring 17 is installed in the fourth annular groove. The third and fourth rubber rings 16, 17 function as seals and vibration dampers.

[0022] As shown in Figures 1 to 6, the end of the shaft case 3 closest to the shaft rod 1 is open, and a threaded structure is formed on the inner wall of this end. A shaft cover 10 is screwed onto this threaded structure. The installation of the shaft cover 10 facilitates assembly of the internal components, prevents dust from entering the shaft case 3 and adversely affecting the use efficiency of the bearing 7, and also reduces noise during operation of the bearing 7. A through-hole is formed in the center of the shaft cover 10 through which the first clamping member 4 passes. The end of the shaft case 3 away from the shaft rod 1 is also formed with a through-hole through which the first clamping member 4 passes, and a first annular groove is formed in the outer cylindrical wall of this end, into which a first rubber ring 11 is installed. A second annular groove is formed in the outer cylindrical wall of the shaft cover 10, and a second rubber ring 12 is installed in the second annular groove. The installation of the first and second rubber rings 11 and 12 helps to reduce vibration between the shaft cover and the mounting housing of a nail grinder or other grinding tool.

[0023] As shown in Figures 1 to 6, one end of the axial rod 1 is inserted into the axial sleeve 2 and connected to rotate synchronously with the axial sleeve 2. The other end of the axial rod 1 is inserted into the third clamping member 6 and connected to rotate synchronously therewith. The third clamping member 6 has an openable clamping opening at its end away from the axial rod 1, and a grinding rod 18 is attached to the clamping opening. In this manner, when the motor of the grinding machine rotates, the axial sleeve 2 drives and rotates the axial rod 1, which in turn drives and rotates the third clamping member 6 and the grinding rod 18. Two bearings 7 and a limiting sleeve case 13 are installed in the shaft case 3. The limiting sleeve case 13 has an annular structure and the outer diameter of the limiting sleeve case 13 is the same as the bore diameter of the shaft case 3. The limiting sleeve case 13 is located between the two bearings 7, and both ends of the limiting sleeve case 13 respectively contact the outer rings of the two bearings 7. A first clamping member 4 is installed within the two bearings 7, and both ends of the first clamping member 4 respectively pass through the shaft case 3 and the shaft cover 10.

[0024] As shown in FIGS. 2 to 6, the first clamping member 4 is a hollow round tube, and the second clamping member 5 and the third clamping member 6 are both located within the first clamping member 4.The member 5 is located on the side of the third clamping member 6 away from the axial rod 1, the first clamping member 4 is fixedly connected to the second clamping member 5, and the first clamping member 4 and the third clamping member 6 are connected to be slidable back and forth. A first round tube portion 601 is installed on one end of the axial rod 1, and one end of the third clamping member 6 is inserted into the first round tube portion 601 and rotates synchronously with the first round tube portion 601. The third clamping member 6 further includes a third round tube portion 603, the end of which facing the first round tube portion 601 is a clamping opening, and a plurality of open / close slits 604 are formed in the tube wall of the clamping opening along the circumferential direction, and synchronous rotation with the first round tube portion 601 is achieved by a fixed connection or other means. A protrusion structure 605 is installed on the outer wall of the clamping opening of the third circular tube portion 603, the second clamping member 5 is hollow circular tube-shaped, one end of the second clamping member 5 extends to the outside of the first clamping member 4, the other end of the second clamping member 5 is fitted into the clamping opening of the third clamping member 6, and the second clamping member 5 has a fitting opening whose diameter gradually decreases at the end, so that the protrusion structure 605 can be tightened and loosened by moving the fitting opening, and further the opening and closing of the opening slit 604 can be realized, i.e., the clamping opening can be loosened and tightened. At the same time, the third clamping member 6 and the second clamping member 5 are linked together, so that when the third clamping member 6 rotates, the second clamping member 5 rotates synchronously. A first spring 19 is fitted to the third clamping member 6, which includes a second cylindrical tube 602 attached to the outer wall of the third clamping member 6. One end of the first spring 19 is in elastic contact with the second cylindrical tube 602, and the other end of the first spring 19 is in elastic contact with the second clamping member 5. The second cylindrical tube 602 on the third clamping member 6 presses the first spring 19 against the second clamping member 5, causing the inner wall of the second clamping member 5 to push out the clamping opening of the third clamping member 6, contracting the clamping opening on the third clamping member 6 and clamping it, i.e., the clamping opening clamps the polishing rod 18. The first clamping member 4 includes a first cylindrical mounting tube and a second cylindrical mounting tube, and the bore diameter of the first cylindrical mounting tube is larger than that of the second cylindrical mounting tube.Both the second round tube portion 602 and the third round tube portion 603 of the third clamping member 6 are completely located within the first mounting round tube portion. The outer diameter of the second round tube portion 602 is larger than the hole diameter of the second mounting round tube portion. The length of the second round tube portion 602 is L1, the distance from the second round tube portion 602 to the protrusion structure 605 is L2. The first clamping member 4 is fixedly connected to the second clamping member 5. The second clamping member 5 is installed within the first mounting round tube portion of the first clamping member 4. The distance between the second clamping member 5 and the second mounting round tube portion is L3, and L3 satisfies the formula L3 < L1 + L2. In this way, it can be realized that the second clamping member 5 does not come off from the third round tube portion 603 of the third clamping member 6.

[0025] As shown in FIGS. 1, FIGS. 2 and FIGS. 3, a positioning ring 8 and a second spring 9 are further installed within the shaft case 3. The second spring 9 is sleeved within the limiting sleeve case 13. Both the positioning ring 8 and the second spring 9 are sleeved on the first clamping member 4. And the positioning ring 8 moves synchronously with the first clamping member 4. The second spring 9 is clamped between the positioning ring 8 and the bearing 7 approaching the shaft rod 1. The positioning ring 8 is installed between the two bearings 7. The positioning ring 8 contacts the adjacent bearing 7. The two bearings 7 are fixedly connected to the first clamping member 4. By installing the two bearings 7, the operating stability of the entire rotating shaft structure is improved. A limiting pushing platform 14 is sleeved on the outer wall of the end of the first clamping member 4 away from the shaft rod 1, and the two move synchronously. The limiting pushing platform 14 is annular. The outer diameter of the limiting pushing platform 14 is larger than the hole diameter of the through hole through which the first clamping member 4 installed on the shaft case 3 passes, so that the limiting pushing platform 14 cannot enter the shaft case 3. Through the mutual engagement of the stepped structure formed by the limiting pushing platform 14, the second round tube portion 602, and the boundary between the first mounting round tube portion and the second mounting round tube portion, the movement of the first clamping member 4 in the axial direction is restricted within a certain range.

[0026] The operating principle of the present invention is as follows: the polishing rod 18 is attached to the clamping opening of the third clamping member 6, and when the motor of the polishing machine rotates, the shaft sleeve 2 drives and rotates the shaft rod 1, which in turn drives and rotates the third clamping member 6, the second clamping member 5, and the first clamping member 4, and when the third clamping member 6 rotates, the polishing rod 18 is driven and rotated, thereby polishing nails or other objects. When replacing the polishing rod 18, the limiting pusher 14 is pushed, which drives the first clamping member 4, the second clamping member 5, the positioning ring 8, the two bearings 7, and the shaft case 3 to move synchronously. A certain distance of relief space is provided between the first clamping member 4 and the shaft rod 1, allowing the third clamping member 6 to slide a certain distance toward the shaft rod 1. As the second clamping member 5 moves, it pushes out the first spring 19, which is compressed. As the first spring 19 is compressed, the fitting opening of the second clamping member 5 loosens the protrusion structure 605 of the third clamping member 6, opening the opening / closing slit 604. In this way, the polishing rod 18 can be removed and replaced. After the replacement of the polishing rod 18 is completed, the first clamping member 4 and the limiting push table 14 are loosened, and the return action of the first spring 19 causes the first spring 19 to push the second clamping member 5, thereby synchronously restoring the first clamping member 4, positioning ring 8, two bearings 7, and shaft case 3, and by abutting or tightening the second clamping member 5, the fitting opening of the second clamping member 5 tightens the protrusion structure 605 of the third clamping member 6, closing the opening / closing slit 604, and in this way the polishing rod 18 can be tightened.

[0027] In short, the rotating shaft structure for a grinding machine according to the present invention allows for easy replacement of the grinding rod 18 during use, facilitating user operation and improving the user experience. The rotating shaft structure for a grinding machine according to the present invention is provided with the shaft sleeve 2, which makes the connection between the shaft rod 1 and the grinding machine motor more stable, facilitating assembly, and also has the advantage of reducing vibration, improving the operational stability and reducing operating noise of the grinding machine.

[0028] The above is merely a preferred embodiment of the present invention, and is not intended to limit the present invention. Those skilled in the art can make various modifications and changes to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall all fall within the protection scope of the present invention. [Explanation of symbols]

[0029] 1 shaft rod 101 insertion rod portion 2 shaft sleeve 201 stroke chamber 202 non-circular connection through hole 3 shaft case 4 first clamping member 5 second clamping member 6 third clamping member 601 first round tube portion 602 second round tube portion 603 third round tube portion 604 opening and closing slit 605 protrusion structure 7 bearing 8 positioning ring 9 second spring 10 shaft cover 11 first rubber ring 12 second rubber ring 13 limiting sleeve case 14 limiting push table 15 limiting member 16 third rubber ring 17 fourth rubber ring 18 polishing rod 19 first spring

Claims

1. A rotating shaft structure for a grinding machine, comprising an axial rod and an axial sleeve, further comprising a shaft case, a first clamping member, a second clamping member and a third clamping member, one end of the axial rod is connected to the axial sleeve and the other end of the axial rod is connected to the third clamping member, the third clamping member has an openable and closable clamping opening at an end remote from the axial rod, the first clamping member is a hollow round tube, the second clamping member and the third clamping member are both located within the first clamping member, and the second clamping member is located on the side of the third clamping member remote from the axial rod, an end of the second clamping member is fitted into the clamping opening of the third clamping member, and the first clamping member and the third clamping member a third clamping member and a third clamping member are connected to each other so as to be slidable back and forth; a first spring is mounted on the third clamping member; the third clamping member includes a second round tube portion installed on an outer wall of the third clamping member; one end of the first spring is in elastic contact with the second round tube portion and the other end of the first spring is in elastic contact with the second clamping member; the first spring is abutted against the second clamping member by the second round tube portion on the third clamping member; the inner wall of the second clamping member pushes out the clamping opening of the third clamping member, causing the clamping opening on the third clamping member to contract and be in a clamped state.

2. 2. The rotating shaft structure for a grinding machine according to claim 1, wherein a first round tube portion is installed at one end of the shaft rod, one end of the third clamping member is inserted into the first round tube portion and rotates synchronously with the first round tube portion, the third clamping member further includes a third round tube portion, an end of the third round tube portion facing the first round tube portion is a clamping opening, and a plurality of opening / closing slits are installed in the tube wall of the clamping opening along the circumferential direction.

3. 3. The rotating shaft structure for a grinding machine according to claim 2, wherein a protrusion structure is provided on an outer wall of the clamping opening of the third circular tube portion, the second clamping member is a hollow circular tube, one end of the second clamping member extends to the outside of the first clamping member, and the end of the second clamping member fitted in the clamping opening has a fitting opening with a gradually decreasing diameter.

4. 4. The rotating shaft structure for a grinding machine according to claim 3, wherein the first clamping member includes a first circular mounting tube portion and a second circular mounting tube portion, the hole diameter of the first circular mounting tube portion is larger than the hole diameter of the second circular mounting tube portion, the second circular mounting tube portion and the third circular mounting tube portion of the third clamping member are both located completely within the first circular mounting tube portion, the outer diameter of the second circular mounting tube portion is larger than the hole diameter of the second circular mounting tube portion, the length of the second circular tube portion is L1, the distance from the second circular tube portion to the protrusion structure is L2, the first clamping member is fixedly connected to the second clamping member, the second clamping member is installed within the first circular mounting tube portion of the first clamping member, the distance between the second clamping member and the second circular mounting tube portion is L3, and L3 satisfies the formula L3<L1+L2.

5. 2. The rotating shaft structure for a grinding machine according to claim 1, characterized in that two bearings are installed in the shaft case, the first clamping member is installed in the two bearings, and both ends of the first clamping member pass through both ends of the shaft case, a positioning ring and a second spring are further installed in the shaft case, the positioning ring and the second spring are both fitted to the first clamping member, and the second spring is clamped between the positioning ring and the bearing closest to the shaft rod, the end of the shaft case closer to the shaft rod is open, and a threaded structure is installed on the inner wall of said end, and a shaft cover is attached to said threaded structure by screws, and a through hole is installed in the center of the shaft cover through which the first clamping member passes.

6. 6. The rotating shaft structure for a grinding machine according to claim 5, wherein the shaft case has a through hole at an end remote from the shaft rod, through which the first clamping member passes, and a first annular groove is formed on the outer cylindrical wall of said end, a first rubber ring is installed in said first annular groove, a second annular groove is formed on the outer cylindrical wall of the shaft cover, and a second rubber ring is installed in said second annular groove.

7. 7. The rotating shaft structure for a grinding machine according to claim 6, wherein a limiting pusher is fitted to the outer wall of the end of the first clamping member away from the shaft rod, the limiting pusher is annular, and the outer diameter of the limiting pusher is larger than the diameter of the through hole through which the first clamping member installed in the shaft case passes.

8. 2. The rotating shaft structure for a grinding machine according to claim 1, characterized in that a limiting sleeve case is further installed in the shaft case, the limiting sleeve case has a circular structure, the outer diameter of the limiting sleeve case is the same as the hole diameter of the shaft case, the limiting sleeve case is located between two bearings, and both ends of the limiting sleeve case respectively contact the outer rings of the two bearings.

9. 2. The rotary shaft structure for a grinding machine according to claim 1, wherein the shaft sleeve is provided with a stroke chamber and a non-circular connecting through-hole, the end of the shaft rod connected to the shaft sleeve is provided with an insertion rod portion that fits into the non-circular connecting through-hole, and the insertion rod portion of the shaft rod passes through the stroke chamber and is inserted into the non-circular connecting through-hole of the shaft sleeve.

10. 10. The rotary shaft structure for a grinding machine according to claim 9, wherein a limiting member is fixedly installed on the axial rod, the limiting member is located near the center of the axial rod, the axial rod main body is between the insertion rod portion and the limiting member, a third annular groove is provided at an end of the axial rod main body near the insertion rod portion, a third rubber ring is installed in the third annular groove, a fourth annular groove is provided on an inner wall of an end of the axial sleeve away from the axial rod, and a fourth rubber ring is installed in the fourth annular groove.

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