Guide sleeve double anti-off assembly, main steam combined valve and assembling method

Abstract

The present application relates to power station valve technical field, especially to a guide sleeve double anti -falling assembly, main steam combined valve and assembly method, guide sleeve double anti -falling assembly includes valve stem, bushing and guide sleeve. Valve stem is inserted in the first through hole of bushing, and the first annular groove and the second annular groove are set up on the inner wall of first through hole, the slot bottom of first annular groove is set up with the inserted slot, the inserted slot extends along the axial direction of bushing and both ends are through, the diameter of the cross section of second annular groove is greater than the diameter of the cross section of first annular groove. Guide sleeve is set on valve stem, and the first limit protruding part is set up on the outer wall of one end of guide sleeve, when guide sleeve is inserted into first annular groove, first limit protruding part moves to second annular groove through inserted slot, guide sleeve rotates first preset angle along the axial direction of itself relative to bushing, so that first limit protruding part is set apart from inserted slot, and the vertical distance between the highest point of first limit protruding part and the axial direction of guide sleeve is greater than the radius of the cross section of first annular groove.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power station valves, in particular to a guide sleeve double anti-disengagement assembly, a main steam combined valve and an assembling method. BACKGROUND

[0002] In an ultra-supercritical power generating unit, the performance of the main steam combined valve of the steam turbine is directly related to whether the steam turbine can operate normally. After the main steam combined valve has been operated for many years, problems such as jamming and poor closing are common, and through investigation, it is found that after the main steam combined valve has been operated for many years, the material performance decreases, and under the action of the friction force of the inner surface of the valve stem on the guide sleeve, the guide sleeve will partially disengage from the original position of the bushing of the valve stem and cannot be reset, which causes the main steam combined valve to close loosely and causes serious safety hazards. SUMMARY

[0003] An object of the present application is to provide a guide sleeve double anti-disengagement assembly which can prevent the guide sleeve from disengaging from the bushing and ensure that the main steam combined valve can be closed tightly, thereby ensuring the safety of the main steam combined valve.

[0004] To achieve this object, the present application adopts the following technical solutions:

[0005] The present application provides a guide sleeve double anti-disengagement assembly, which comprises:

[0006] a valve stem;

[0007] a bushing, the valve stem being inserted into a first through hole of the bushing, a first annular groove and a second annular groove being sequentially formed on the inner wall of the first through hole along the axial direction of the bushing, one end of the first annular groove being an opening of the first through hole, an insertion groove being formed in the groove bottom of the first annular groove, the insertion groove extending along the axial direction of the bushing and being through at both ends, and the diameter of the cross section of the second annular groove being greater than the diameter of the cross section of the first annular groove;

[0008] a guide sleeve, the guide sleeve being sleeved on the valve stem, a first limiting protruding portion being arranged on the outer wall of one end of the guide sleeve, the first limiting protruding portion being moved to the second annular groove through the insertion groove when the guide sleeve is inserted into the first annular groove, the guide sleeve being rotated by a first preset angle along the axial direction of itself relative to the bushing so that the first limiting protruding portion is arranged away from the insertion groove, and the vertical distance between the highest point of the first limiting protruding portion and the axial direction of the guide sleeve being greater than the radius of the cross section of the first annular groove.

[0009] Optionally, the guide sleeve and the groove bottom of the first annular groove are in interference fit.

[0010] Optionally, the guide sleeve is provided with N first limiting protrusions, the bottom of the first annular groove is provided with N insertion grooves, the N first limiting protrusions are arranged in one-to-one correspondence with the N insertion grooves, and N is a positive integer.

[0011] Optionally, the N first limiting protrusions are uniformly arranged on the guide sleeve.

[0012] Optionally, when N is greater than or equal to 2, the bottom of the first annular groove has a second limiting protrusion, and the second limiting protrusion is located between two adjacent insertion grooves.

[0013] Optionally, the first preset angle α satisfies 180° / N-20°≤α≤180° / N+20°.

[0014] Optionally, the radius of the cross section of the second annular groove is greater than the vertical distance between the highest point of the first limiting protrusion and the guide sleeve in the axial direction.

[0015] Optionally, the valve head is connected to one end of the valve rod, the valve head has a protruding support portion, one end of the bushing provided with the first annular groove has a support groove, and the protruding support portion is inserted into the support groove.

[0016] Another object of the present application is to provide a main steam combined valve, which can avoid the disengagement of the guide sleeve and the bushing, ensure that the main steam combined valve can be tightly closed, and thus ensure the use safety of the main steam combined valve.

[0017] To achieve the above object, the present application adopts the following technical solutions.

[0018] The present application provides a main steam combined valve, which comprises a housing and the above-mentioned guide sleeve double anti-disengagement assembly, and the guide sleeve double anti-disengagement assembly is arranged in the housing.

[0019] Another object of the present application is to provide an assembly method, which can avoid the disengagement of the guide sleeve and the bushing, ensure that the main steam combined valve can be tightly closed, and thus ensure the use safety of the main steam combined valve.

[0020] To achieve the above object, the present application adopts the following technical solutions.

[0021] The present application provides an assembly method, which is applied to the above-mentioned guide sleeve double anti-disengagement assembly, and the assembly method comprises the following steps.

[0022] Preparation stage: the guide sleeve is soaked in liquid nitrogen for cooling, so that the size of the guide sleeve becomes smaller, and the bushing is heated, so that the size of the bushing becomes larger.

[0023] Assembly stage: insert the guide sleeve into the first annular groove of the bushing, align the first limiting protrusion with the insertion groove, and move through the insertion groove to the second annular groove, and the guide sleeve rotates the first preset angle along its own axis relative to the bushing so that the first limiting protrusion is staggered with the insertion groove.

[0024] Beneficial effects of the present invention:

[0025] The present invention provides a guide sleeve double anti-slip assembly, comprising a valve stem, a bushing and a guide sleeve. The valve stem is inserted into a first through hole of the bushing, and a first annular groove and a second annular groove are sequentially provided on the inner wall of the first through hole along the axial direction of the bushing. One end of the first annular groove is the opening of the first through hole, and an insertion groove is provided at the bottom of the first annular groove. The insertion groove extends along the axial direction of the bushing and is through-connected at both ends. The diameter of the cross section of the second annular groove is greater than the diameter of the cross section of the first annular groove. The guide sleeve is sleeved on the valve stem, and a first limiting protrusion is provided on the outer wall of one end of the guide sleeve. When the guide sleeve is inserted into the first annular groove, the first limiting protrusion moves to the second annular groove through the insertion groove. The guide sleeve rotates relative to the bushing along its own axial direction by a first preset angle so that the first limiting protrusion is staggered with the insertion groove, and the vertical distance between the highest point of the first limiting protrusion and the axial direction of the guide sleeve is greater than the radius of the cross section of the first annular groove. The step surface between the first annular groove and the second annular groove can limit the movement of the first limiting protrusion, which can effectively prevent the guide sleeve from separating from the bushing, and by providing an insertion groove at the bottom of the first annular groove, the first limiting protrusion can be easily slid into the second annular groove. When the diameter of the cross section of the first annular groove is constant, the protruding height of the first limiting protrusion can be increased by deepening the depth of the insertion groove, thereby improving the anti-separation performance of the guide sleeve.

[0026] The present invention also provides a main steam combined valve comprising a housing and the aforementioned guide sleeve double anti-detachment assembly, the guide sleeve double anti-detachment assembly being disposed within the housing. This main steam combined valve prevents the guide sleeve from separating from the bushing, ensuring a tight closure of the main steam combined valve and thus ensuring safe operation.

[0027] The present invention also provides an assembly method, which is applied to the above-mentioned guide sleeve double anti-detachment assembly, and the assembly method includes the following steps: a preparatory stage: immersing the guide sleeve in liquid nitrogen to cool it down so that the size of the guide sleeve becomes smaller, and heating the bushing to increase the size of the bushing; an assembly stage: inserting the guide sleeve into the first annular groove of the bushing, aligning the first limiting protrusion with the insertion groove, and moving it to the second annular groove through the insertion groove, and rotating the guide sleeve relative to the bushing along its own axis by a first preset angle so that the first limiting protrusion and the insertion groove are staggered. The guide sleeve double anti-detachment assembly obtained by adopting this assembly method can prevent the guide sleeve from detaching from the bushing, ensure that the main steam combined valve can be closed tightly, and thus ensure the safety of the main steam combined valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a cross-sectional view of a guide sleeve double anti-slip assembly provided by an embodiment of the present invention from a first perspective;

[0029] Figure 2 is a cross-sectional view of a guide sleeve double anti-slip assembly provided by an embodiment of the present invention from a second perspective;

[0030] Figure 3 2. It is a structural schematic diagram of a guide sleeve double anti-slip assembly provided in an embodiment of the present invention;

[0031] Figure 4 1 is a schematic diagram of the assembly of the guide sleeve and the bushing provided in an embodiment of the present invention;

[0032] Figure 5 is a cross-sectional view of a bushing provided by an embodiment of the present invention;

[0033] Figure 6 is a schematic structural diagram of a bushing provided in an embodiment of the present invention;

[0034] Figure 7 is a cross-sectional view of a guide sleeve provided by an embodiment of the present invention;

[0035] Figure 8 1 is a schematic structural diagram of a guide sleeve provided in an embodiment of the present invention;

[0036] Figure 9 It is a flow chart of the assembly method provided by an embodiment of the present invention.

[0037] In the picture:

[0038] 1. Valve stem; 2. Bushing; 21. First annular groove; 211. Insertion groove; 22. Second annular groove; 23. Support groove;

[0039] 3. Guide sleeve; 31. First limit protrusion; 4. Valve head; 41. Protruding support portion; 5. Locking nut. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only show portions relevant to the present invention, not all of them.

[0041] In the description of the present application, it is necessary to point out that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0043] As shown in Figures 1-8 The guide sleeve double anti-disengagement assembly of the embodiment includes a valve stem 1, a bushing 2 and a guide sleeve 3. The bushing 2 is sleeved on the valve stem 1, a first annular groove 21 and a second annular groove 22 are sequentially formed on the inner wall of the first through hole of the bushing 2 along the axial direction of the bushing 2, one end of the first annular groove 21 is the opening of the first through hole, an insertion groove 211 is formed on the groove bottom of the first annular groove 21, that is, the insertion groove 211 is formed on the inner wall of the through hole of the bushing 2, and the insertion groove 211 is located only at the first annular groove 21. The insertion groove 211 extends along the axial direction of the bushing 2 and penetrates through both ends, and the diameter of the cross section of the second annular groove 22 is greater than that of the first annular groove 21. The guide sleeve 3 is sleeved on the valve stem 1, a first limiting protruding part 31 is arranged on the outer wall of one end of the guide sleeve 3, when the guide sleeve 3 is inserted into the first annular groove 21, the first limiting protruding part 31 moves to the second annular groove 22 through the insertion groove 211, the guide sleeve 3 rotates by a first preset angle along the axial direction of itself relative to the bushing 2, so that the first limiting protruding part 31 is arranged away from the insertion groove 211, and the vertical distance between the highest point of the first limiting protruding part 31 and the axial direction of the guide sleeve 3 is greater than the radius of the cross section of the first annular groove 21. It can be known that the cross section of the valve stem 1 is circular, the cross sections of the inner wall and the outer wall of the main body of the guide sleeve 3 are both circular rings, and the cross sections of the groove bottoms of the first annular groove 21 and the second annular groove 22 are both circular rings.

[0044] The step surface between the first annular groove 21 and the second annular groove 22 can limit the movement of the first limiting protrusion 31, and can effectively prevent the guide sleeve 3 from being separated from the bushing 2. The insertion groove 211 is arranged at the bottom of the first annular groove 21, so that the first limiting protrusion 31 can slide into the second annular groove 22 and rotate by a certain angle. In the case that the cross-sectional diameter of the first annular groove 21 is constant, the protruding height of the first limiting protrusion 31 can be increased by deepening the depth of the insertion groove 211, thereby improving the anti-separation performance of the guide sleeve 3, and effectively avoiding the problem that the main steam combined valve cannot be tightly closed due to the protrusion of the guide sleeve 3, so as to ensure the safety of the main steam combined valve.

[0045] Optionally, the guide sleeve 3 is in interference fit with the bottom of the first annular groove 21, that is, the outer wall of the guide sleeve 3 abuts against the bottom of the first annular groove 21. The areas of the two surfaces are large, so that the guide sleeve 3 can still not rotate and slide relative to the bushing 2 under the condition of bearing a large axial force, torque and dynamic load.

[0046] It can be known that, if the insertion groove 211 is not arranged, in order to ensure that the guide sleeve 3 is in interference fit with the bottom of the first annular groove 21, the protruding size of the first limiting protrusion 31 on the guide sleeve 3 needs to be as small as possible, so as to avoid that the friction between the first limiting protrusion 31 and the inner wall of the bushing 2 is too large. The too large friction will lead to difficult assembly on one hand, and the root of the first limiting protrusion 31 is easy to be damaged on the other hand. After working for a period of time, the first limiting protrusion 31 is easy to be broken and fail, so that the guide sleeve 3 is easy to be separated from the bushing 2.

[0047] Optionally, the guide sleeve 3 is provided with N first limiting protrusions 31, the bottom of the first annular groove 21 is provided with N insertion grooves 211, and the N first limiting protrusions 31 and the N insertion grooves 211 are arranged one by one, and N is a positive integer. That is, the N first limiting protrusions 31 can pass through the N insertion grooves 211 respectively, and finally enter the second annular groove 22. In this embodiment, N is 4, that is, four first limiting protrusions 31 correspond to four insertion grooves 211 respectively. Of course, in other embodiments, N can be 1, 2, 3, 5, 6, 7 or other larger positive integers, which can be adjusted as required and is not limited herein.

[0048] Optionally, the N first limiting protrusions 31 are uniformly arranged on the guide sleeve 3. That is, the N first limiting protrusions 31 are uniformly arranged on the outer wall of the guide sleeve 3 in the circumferential direction, and the N insertion grooves 211 are uniformly arranged on the inner wall of the first annular groove 21 of the bushing 2 in the circumferential direction.

[0049] Optionally, when N is greater than or equal to 2, the bottom of the second annular groove 22 has a second limiting protrusion between two adjacent insertion grooves 211, which can prevent the first limiting protrusion 31 from moving excessively. Once the first limiting protrusion 31 moves excessively, it can correspond to the position of the adjacent insertion groove 211, and the first limiting protrusion 31 is easy to be separated from the second annular groove 22 and enter the insertion groove 211, so that the limiting effect of the first limiting protrusion 31 is lost, and the guide sleeve 3 is separated from the bushing 2.

[0050] Optionally, the first preset angle a satisfies 180° / N-20°≤a≤180° / N+20°. When N is 4, a satisfies 25°≤a≤65°. For the setting of the first preset angle value range, it can prevent the guide sleeve 3 from rotating excessively relative to the bushing 2, so that the first limiting protrusion 31 easily separates from the second annular groove 22 and enters the insertion groove 211, so that the limiting effect of the first limiting protrusion 31 is lost. Optionally, in the embodiment, the value of N is 4, and the first preset angle a is 30°.

[0051] Optionally, the radius of the cross section of the second annular groove 22 is greater than the vertical distance between the highest point of the first limiting protrusion 31 and the axial direction of the guide sleeve 3. That is, the outer wall of the first limiting protrusion 31 does not contact the bottom of the second annular groove 22, avoiding that the first limiting protrusion 31 bears axial force and causes the first limiting protrusion 31 to break and fail.

[0052] Optionally, the vertical distance between the bottom of the insertion groove 211 and the axial direction of the bushing 2 is greater than the vertical distance between the highest point of the first limiting protrusion 31 and the axial direction of the guide sleeve 3, that is, during the process of inserting the guide sleeve 3 into the bushing 2, the outer wall surface of the first limiting protrusion 31 does not contact the bottom of the insertion groove 211, so as to further ensure that the first limiting protrusion 31 is not stressed and damaged.

[0053] Optionally, the groove width of the insertion groove 211 is greater than the width of the first limiting protrusion 31, that is, the circumferential dimension of the insertion groove 211 along the bushing 2 is greater than the circumferential dimension of the first limiting protrusion 31 along the guide sleeve 3, that is, the two sides of the first limiting protrusion 31 do not contact the side wall of the insertion groove 211, that is, during the process of inserting the guide sleeve 3 into the bushing 2, the side wall surface of the first limiting protrusion 31 does not contact the inner side wall of the insertion groove 211, so as to further ensure that the first limiting protrusion 31 is not stressed and damaged.

[0054] Optionally, the guide sleeve double anti-disengagement assembly further comprises a valve head 4 connected to one end of the valve rod 1, the valve head 4 has a protruding support part 41, one end of the bushing 2 having the first annular groove 21 has a support groove 23, the protruding support part 41 is inserted into the support groove 23. The valve head 4 penetrates to form a second through hole, one end of the second through hole has an internal thread, the locking nut 5 has an external thread, the locking nut 5 is inserted into the end of the second through hole, and the external thread is matched with the internal thread. The end surface of the locking nut 5 facing the valve head 4 is provided with a groove, the side wall of the groove has an internal thread, and one end of the valve rod 1 is screwed to the internal thread of the locking nut 5 through the second through hole.

[0055] The outer wall of the main body of the guide sleeve 3 of the guide sleeve double anti-disengagement assembly is in interference fit with the groove bottom of the first annular groove 21, so that the two surfaces in contact can withstand larger axial force, torque and dynamic load, so that the guide sleeve 3 is not easy to rotate or slide relative to the bushing 2. After the first limiting protruding part 31 of the guide sleeve 3 enters the second annular groove 22, the first limiting protruding part 31 is rotated to be misaligned with the insertion slot 211 of the bushing 2, and the movement of the first limiting protruding part 31 can be limited by the stepped surface between the first annular groove 21 and the second annular groove 22. The axial movement of the guide sleeve 3 relative to the bushing 2 caused by the reciprocating movement of the valve rod 1 can be effectively avoided, so that the problem of the main steam combined valve not being tightly closed due to the protrusion of the guide sleeve 3 from the bushing 2 can be avoided.

[0056] The embodiment also provides a main steam combined valve, which comprises a housing and the guide sleeve double anti-disengagement assembly described above, and the guide sleeve double anti-disengagement assembly is arranged in the housing. The main steam combined valve can avoid the disengagement of the guide sleeve 3 from the bushing 2, ensure that the main steam combined valve can be tightly closed, and thus ensure the use safety of the main steam combined valve.

[0057] As shown in Figure 9 The embodiment also provides an assembly method, which is applied to the guide sleeve double anti-disengagement assembly described above, and the assembly method comprises a preparation stage and an assembly stage.

[0058] The preparation stage: since the outer wall of the main body of the guide sleeve 3 is in interference fit with the groove bottom of the first annular groove 21, in order to facilitate the assembly of the guide sleeve 3 into the bushing 2, the guide sleeve 3 and the bushing 2 need to be prepared according to the principle of thermal expansion and cold contraction. Optionally, the guide sleeve 3 is soaked in liquid nitrogen to reduce the size of the guide sleeve 3. At this time, an assembly attempt can be made, and if the guide sleeve 3 still cannot be assembled into the bushing 2, the bushing 2 is further heated to increase the size of the bushing 2.

[0059] The assembly stage: the guide sleeve 3 is inserted into the first annular groove 21 of the bushing 2, the first limiting protruding part 31 is aligned with the insertion slot 211, and is moved to the second annular groove 22 through the insertion slot 211, the guide sleeve 3 is rotated by a first preset angle relative to the bushing 2 along the axial direction of the guide sleeve 3, so that the first limiting protruding part 31 is misaligned with the insertion slot 211.

[0060] The double anti-disengagement assembly of the guide sleeve obtained by using the assembly method can avoid disengagement of the guide sleeve 3 from the bushing 2, ensure that the main steam combined valve can be tightly closed, and thus ensure the use safety of the main steam combined valve.

[0061] Obviously, the above embodiments of the present application are merely exemplary and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is not necessary or possible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. The double anti-drop assembly of the guide sleeve is characterized by: include: Valve stem (1); A bushing (2), the valve stem (1) is inserted into a first through hole of the bushing (2), a first annular groove (21) and a second annular groove (22) are sequentially provided on the inner wall of the first through hole along the axial direction of the bushing (2), one end of the first annular groove (21) is the opening of the first through hole, an insertion groove (211) is provided at the bottom of the first annular groove (21), the insertion groove (211) extends along the axial direction of the bushing (2) and is through-connected at both ends, and the diameter of the cross section of the second annular groove (22) is larger than the diameter of the cross section of the first annular groove (21); A guide sleeve (3), the guide sleeve (3) is sleeved on the valve stem (1), and a first limiting protrusion (31) is provided on the outer wall of one end of the guide sleeve (3). When the guide sleeve (3) is inserted into the first annular groove (21), the first limiting protrusion (31) moves to the second annular groove (22) through the insertion groove (211), and the guide sleeve (3) rotates along its own axial direction by a first preset angle relative to the bushing (2) so that the first limiting protrusion (31) and the insertion groove (211) are staggered, and the vertical distance between the highest point of the first limiting protrusion (31) and the axial direction of the guide sleeve (3) is greater than the radius of the cross section of the first annular groove (21).

2. The guide sleeve double anti-drop assembly according to claim 1, characterized in that: The guide sleeve (3) is interference-fitted with the bottom of the first annular groove (21).

3. The guide sleeve double anti-drop assembly according to claim 1, characterized in that: The guide sleeve (3) is provided with N first limiting protrusions (31), the bottom of the first annular groove (21) is provided with N insertion grooves (211), the N first limiting protrusions (31) are arranged in a one-to-one correspondence with the N insertion grooves (211), and N is a positive integer.

4. The guide sleeve double anti-drop assembly according to claim 3, characterized in that: N first limiting protrusions (31) are evenly spaced and arranged on the guide sleeve (3).

5. The guide sleeve double anti-drop assembly according to claim 3, characterized in that: When N is greater than or equal to 2, the bottom of the first annular groove (21) has a second limiting protrusion, and the second limiting protrusion is located between two adjacent insertion grooves (211).

6. The guide sleeve double anti-drop assembly according to claim 3, characterized in that: The first preset angle α satisfies the following condition: 180° / N-20°≤α≤180° / N+20°.

7. The guide sleeve double anti-drop assembly according to claim 1, characterized in that: The radius of the cross section of the second annular groove (22) is greater than the vertical distance between the highest point of the first limiting protrusion (31) and the axial direction of the guide sleeve (3).

8. The guide sleeve double anti-drop assembly according to claim 1, characterized in that: It also includes a valve head (4), the valve head (4) is connected to one end of the valve stem (1), the valve head (4) has a protruding support portion (41), and the end of the bushing (2) where the first annular groove (21) is opened has a support groove (23), and the protruding support portion (41) is inserted into the support groove (23).

9. Main steam combined valve, characterized in that: It comprises a shell and a guide sleeve double anti-slip assembly according to any one of claims 1 to 8, wherein the guide sleeve double anti-slip assembly is arranged in the shell.

10. Assembly method, characterized in that, Applied to the guide sleeve double anti-slip assembly according to any one of claims 1 to 8, the assembly method comprises the following steps: Preparatory stage: immersing the guide sleeve (3) in liquid nitrogen to reduce the temperature so as to reduce the size of the guide sleeve (3), and heating the bushing (2) so as to increase the size of the bushing (2); Assembly stage: the guide sleeve (3) is inserted into the first annular groove (21) of the bushing (2), the first limiting protrusion (31) is aligned with the insertion groove (211), and is moved to the second annular groove (22) through the insertion groove (211), and the guide sleeve (3) is rotated along its own axial direction by the first preset angle relative to the bushing (2) so that the first limiting protrusion (31) and the insertion groove (211) are staggered.

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