Clamping tool for aero-engine blade machining

Abstract

The invention relates to a clamping tool for aero-engine blade machining, and relates to the field of blade clamping tools, the clamping tool comprises a base plate with an upper plate face and a lower plate face, and the plate face of the base plate is perpendicular to the first direction X; the clamping assembly comprises two clamping blocks, the two clamping blocks are distributed in the second direction Y in a spaced mode, in the second direction Y, the base plate is located between the two clamping blocks, a clamping space is formed by the clamping blocks and the base plate in the second direction Y, and the depth direction of the clamping space is parallel to the first direction X; the clamping block is connected to the clamping block in a sliding mode in the second direction Y so that the length of the clamping space in the second direction Y can be changed. The method has the effect of improving the universality.

Description

Technical Field

[0001] The present application relates to the field of blade clamping tooling, and in particular to a clamping tooling for machining aircraft engine blades. Background Art

[0002] The aircraft engine blade has a shaft body, and the shaft body of the blade needs to be finely processed. During processing, the shaft body of the blade needs to be fixed to reduce the shaking of the shaft body during the processing of the shaft body, so as to improve the processing accuracy as much as possible.

[0003] Reference Figure 1 At present, when clamping the blade shaft 01, a clamping tool is used for clamping. The current clamping tool includes a frame 02, and a clamping hole 022 is opened through the panel 021 of the frame 02. The clamping hole 022 is used for inserting the blade shaft 01. A top screw 03 is also threadedly connected to the panel 021 of the frame 02. After passing through the panel 021, the top screw 03 can extend into the clamping hole 022, so that the blade shaft 01 can be fixed by the top screw 03.

[0004] Regarding the above-mentioned related technologies, since the aperture of the clamping hole is a fixed value, it cannot adapt to blade shafts of different sizes and has poor versatility. Summary of the invention

[0005] In order to improve versatility, the present application provides a clamping tool for machining aircraft engine blades.

[0006] The present application provides a clamping tool for machining aero-engine blades using the following technical solution: A clamping tool for machining an aero-engine blade, comprising: a substrate having an upper surface and a lower surface, wherein the surface of the substrate is perpendicular to the first direction X; and A clamping assembly, the clamping assembly comprising: Two clamping blocks are spaced apart in the second direction Y, and in the second direction Y, the substrate is located between the two clamping blocks, the clamping blocks and the substrate form a clamping space in the second direction Y, and the depth direction of the clamping space is parallel to the first direction X; the clamping block is slidably connected to the clamping block along the second direction Y to change the length of the clamping space in the second direction Y.

[0007] By adopting the above technical solution, when it is necessary to clamp a blade, the blade is inserted into the clamping space, and then the clamping block is moved toward one side of the substrate along the second direction Y, so that the length of the clamping space in the second direction Y can be changed, so that the substrate can be clamped by the clamping block; since the clamping block in the present disclosure can move in the first direction X, if it is necessary to clamp blades of different models, it only needs to move the clamping block to different positions to clamp blades of different models, and it has high versatility.

[0008] Optionally, a first clamping groove is formed on a side of the clamping block close to the clamping space, and an opening of the first clamping groove faces one side of the clamping space.

[0009] By adopting the above technical solution and providing the first clamping groove and the second clamping groove, the length of the entire tooling in the second direction Y can be reduced.

[0010] Optionally, a bidirectional driving component is further included, and the bidirectional driving component includes: A mounting frame, the mounting frame is fixedly connected to the base plate; A rotating rod having an active end and a driven end, wherein two rotating rods are provided, wherein the middle portion of each rotating rod is rotatably connected to the mounting frame via a first rotating shaft, wherein the first rotating shaft is parallel to the third direction Z; the two first rotating shafts are spaced apart in the second direction Y; the active ends of the two rotating rods are located on a side where the two first rotating shafts are close to each other, and the driven ends of the two rotating rods are located on a side where the two first rotating shafts are far away from each other; A pressing driving member, the pressing driving member is slidably connected to the base plate along a first direction X, the pressing driving member is located on a side of the rotating rod close to the base plate, and the pressing driving member is in contact with a side of the driven end close to the base plate; and A push block, each active end of the rotating rod is correspondingly connected with the push block, and in the second direction Y, the push block abuts against a side of the clamping block away from the clamping space; The push block can be adjusted between a clamping posture and a force-unloading posture along with the rotating rod. In the process of the push block moving from the clamping block to the substrate along with the rotating rod, the push block is adjusted from the force-unloading posture to the clamping posture, and in the second direction Y, the straight-line distance between the push block and the clamping space gradually decreases.

[0011] By adopting the above technical solution, when the push block needs to be adjusted from the clamping posture to the unloading posture, it is only necessary to press the downward driving member toward the rotating rod side to move the push block toward the substrate side to clamp the blade.

[0012] Optionally, the push block is detachably connected to the driven end of the rotating rod.

[0013] By adopting the above technical solution, the position of the push block in the second direction Y can be adjusted to adapt to the clamping of blades of different models.

[0014] Optionally, the end of the push block close to the clamping block is in an arc shape with an opening facing an end away from the push block.

[0015] By adopting the above technical solution, one end of the push block close to the clamping block is in an arc shape, which can make the sliding process of the push block along the clamping block smoother.

[0016] Optionally, in the third direction Z, the clamping assemblies are distributed in plurality, and each of the rotating rods is also provided with a plurality of push blocks, and each of the clamping blocks in the clamping assemblies is correspondingly configured with the push blocks.

[0017] By adopting the above technical solution, the clamping blocks in multiple clamping assemblies are driven to move synchronously by a rotating rod, so that more blades can be clamped at one time to improve the working efficiency.

[0018] Optionally, the pressing driving member is penetrated through the base plate along the first direction X, and the pressing driving member is threadably connected to the base plate, and one end of the pressing driving member close to the driven end of the rotating rod can contact the driven end of the rotating rod.

[0019] By adopting the above technical solution, by screwing the pressing driving member, the pressing driving member can drive the active end of the rotating rod to move toward the side away from the substrate, and the threaded connection method is relatively simple and convenient.

[0020] Optionally, it further comprises a protective sleeve having a material hole, wherein the protective sleeve is cylindrical, the material hole is used to accommodate blades, and the clamping space is used for inserting the protective sleeve.

[0021] By adopting the above technical solution, the blade is inserted into the protective sleeve, and the protective sleeve can wrap the blade in all directions. Therefore, inserting the protective sleeve into the clamping space can prevent the substrate and the clamping block from damaging the blade during the process of applying the clamping force.

[0022] Optionally, also include: A limit block having a limit end, the limit block being connected to the base plate; the limit block is arranged on the side of at least one of the clamping spaces; The outer peripheral wall of the protective sleeve is provided with a limiting groove, the limiting groove penetrates the protective sleeve along the first direction X, and the limiting groove is used for the limiting block to be inserted.

[0023] By adopting the above technical solution, when the limiting block is located in the limiting groove, it can prevent the protective sleeve from rotating in the clamping space to a certain extent, and has a certain limiting effect.

[0024] Optionally, the protective sleeve has a first limiting surface and a first avoiding surface in the limiting groove, the first limiting surface is perpendicular to the tangent line of the protective sleeve, and an angle is formed between the first avoiding surface and the first limiting surface; The limiting end of the limiting block has a second limiting surface and a second avoidance surface, the distance between the second limiting surface and the second avoidance surface gradually decreases toward the side of the protective sleeve, and the angle between the second limiting surface and the second avoidance surface is smaller than the angle formed between the first avoidance surface and the first limiting surface; The first limiting surface can rotate along with the protective sleeve to a position in contact with and parallel to the second limiting surface.

[0025] By adopting the above technical solution, since the angle of the limit end is smaller than the angle of the inner wall of the avoidance groove, it is possible to facilitate the insertion of the limit block into the limit groove and avoid interference between the first avoidance surface and the second avoidance surface. The contact between the first limit surface and the second limit surface can prevent the protective sleeve from rotating unidirectionally from the first limit surface to the second limit surface.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: 1. This application can clamp blades of different models and has high versatility; 2. By providing the first clamping groove and the second clamping groove, the length of the entire tooling in the second direction Y can be reduced; 3. The present application can clamp multiple blades simultaneously through a bidirectional drive assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a blade in the related technology of this application; Figure 2 This is a schematic diagram of the overall structure of the first viewing angle of the embodiment of the present application; Figure 3 is a schematic diagram of the overall structure of the second viewing angle of the embodiment of the present application; Figure 4 is a cross-sectional view of an embodiment of the present application; Figure 5 This is a structural view of the guide assembly in the embodiment of the present application; Figure 6 is a schematic structural diagram of a limit block in an embodiment of the present application at a first viewing angle; Figure 7 It is a schematic diagram of the structure of the limit block in the embodiment of the present application at a second viewing angle.

[0028] Description of reference numerals: 01, blade shaft; 02, frame; 021, panel; 022, clamping hole; 03, top screw; 1, base plate; 11, support leg; 12, second clamping groove; 13, guide hole; 14, mounting groove; 15, upper plate surface; 16, lower plate surface; 2, clamping assembly; 21, clamping block; 211, first clamping groove; 22, clamping space; 3, two-way drive assembly; 31, mounting frame; 32, rotation Rod; 321, active end; 322, driven end; 323, first rotating shaft; 324, connecting strip; 33, downward driving member; 34, push block; 4, guide assembly; 41, guide strip; 42, guide rod; 5, protective sleeve; 51, material hole; 52, limiting groove; 521, first limiting surface; 522, first avoidance surface; 6, limiting block; 60, limiting end; 61, second limiting surface; 62, second avoidance surface. DETAILED DESCRIPTION

[0029] The following is combined with Figure 2-7 The present application is further described in detail. For the convenience of description, the present application introduces directional words such as a first direction X, a second direction Y, and a third direction Z to form a three-dimensional reference direction. The directional words used, such as "a first direction X, a second direction Y, and a third direction Z", can be specifically shown with reference to the figure, wherein X represents the first direction X, Y represents the second direction Y, and Z represents the third direction Z, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0030] The present application embodiment discloses a clamping tool for machining aerospace engine blades. Figure 2 The clamping tool for processing aircraft engine blades includes a base plate 1 and a clamping assembly 2 arranged on the base plate 1. The plate surface of the base plate 1 is perpendicular to the first direction X. The two plate surfaces of the base plate 1 are an upper plate surface 15 and a lower plate surface 16. When the first direction X is a vertical direction, the upper surface of the base plate 1 is the upper plate surface 15, and the lower surface is the lower plate surface 16; the clamping assembly 2 is used to clamp the blade to the base plate 1; a support leg 11 is fixedly connected to the base plate 1.

[0031] Reference Figure 2 and Figure 3 The clamping assembly 2 includes two clamping blocks 21, the two clamping blocks 21 are spaced apart in the second direction Y, and the substrate 1 is located between the two clamping blocks 21 in the second direction Y, and the clamping blocks 21 and the substrate 1 form a clamping space 22 in the second direction Y, and the clamping space 22 is arranged through the first direction X to accommodate the blade, and can be used for the blade to be inserted into the clamping space 22 along the first direction X; In order to limit the blade, a first clamping groove 211 is formed on the side of the clamping block 21 close to the substrate 1, and a second clamping groove 12 is formed on the side of the substrate 1 close to the clamping block 21. The clamping space 22 is formed by the groove wall of the first clamping groove 211 and the groove wall of the second clamping groove 12. The clamping block 21 is slidably connected to the base plate 1 along the second direction Y to change the length of the clamping space 22 in the second direction Y. The blade can be clamped or loosened by changing the length of the clamping space 22 in the second direction Y.

[0032] Reference Figure 3 In some embodiments of the present application, a plurality of clamping assemblies 2 are provided, and the plurality of clamping assemblies 2 are spaced apart and distributed in the third direction Z. Preferably, two clamping assemblies 2 are provided in the present disclosure.

[0033] Reference Figure 3 and Figure 4 In order to facilitate driving the two clamping blocks 21 to clamp the blades at the same time, in some embodiments of the present application, a bidirectional driving assembly 3 is also included, the bidirectional driving assembly 3 includes a mounting frame 31 and a rotating rod 32 having an active end 321 and a driven end 322, and also includes a downward driving member 33 and a push block 34; The mounting frame 31 is fixedly connected to the substrate 1, and two mounting frames 31 are distributed in the second direction Y; in the second direction Y, the substrate 1 is located between the two mounting frames 31; Two rotating rods 32 are provided, and the middle part of each rotating rod 32 is rotatably connected to the mounting frame 31 through a first rotating shaft 323, and the first rotating shaft 323 is located between the active end 321 and the driven end 322, and the two first rotating shafts 323 are spaced apart in the second direction Y, and the first rotating shafts 323 are parallel to the third direction Z; in the second direction Y, the active ends 321 of the two rotating rods 32 are located on the side where the two first rotating shafts 323 are close to each other, and the driven ends 322 of the two rotating rods 32 are located on the side where the two first rotating shafts 323 are away from each other; In order to push the active end 321 of the rotating rod 32 from the upper plate surface 15 to the lower plate surface 16 of the substrate 1, the pressing driving member 33 is penetrated in the substrate 1 along the first direction X, and the pressing driving member 33 has a pressing end, which contacts the side of the active end 321 close to the substrate 1. Therefore, in the process of moving the pressing driving member 33 to the side of the rotating rod 32, the pressing driving member 33 can push the rotating rod 32 to rotate; in some embodiments of the present application, the pressing driving member 33 is threadedly connected to the substrate 1. Therefore, in the process of rotating the pressing driving member 33 along the substrate 1, the pressing driving member 33 can press the rotating rod 32 toward the side away from the substrate 1; preferably, the pressing driving member 33 in the present disclosure is a bolt; In the first direction X, when the two active ends 321 are pressed from the upper plate surface 15 to the lower plate surface 16 at the same time, the driven end 322 will rotate from the lower plate surface 16 to the upper plate surface 15, so that the rotating rod 32 is adjusted from the unloading posture to the clamping posture; when the rotating rod 32 is in the unloading posture, the rotating rod 32 is parallel to the second direction Y, and during the process of the rotating rod 32 rotating from the unloading posture to the clamping posture, the driven end 322 of the rotating rod 32 rotates from the lower plate surface 16 to the upper plate surface 15; The push block 34 is detachably connected to the rotating rod 32. Specifically, the push block 34 is fixedly connected to the rotating rod 32 by screws, and the push block 34 is located on the side of the clamping block 21 away from the substrate 1, so that when the rotating rod 32 rotates from the unloading posture to the clamping posture, the push block 34 pushes the clamping block 21 toward the side of the substrate 1; in the present disclosure, each clamping block 21 is correspondingly configured with a push block 34; in order to install a plurality of push blocks 34 on the driven end 322 of the rotating rod 32, a connecting strip 324 is detachably connected to the driven end 322 of the rotating rod 32 by screws. In the case of the connecting strip 324, the connecting strip 324 in the present disclosure is detachably connected to the push block 34 by screws, and the connecting strip 324 is parallel to the third direction Z, and a plurality of push blocks 34 are fixedly connected to the connecting strip 324; In order to improve the smoothness of the movement of the clamping block 21 by the push block 34, in some embodiments of the present application, the end of the push block 34 close to the clamping block 21 is arc-shaped, and the opening of the arc-shaped faces the side away from the clamping block 21; In addition, since in the present disclosure, the driven end 322 of each rotating rod 32 is fixedly connected with a plurality of push blocks 34, and each push block 34 pushes a corresponding clamping block 21 to move, therefore, a rotating rod 32 can simultaneously push a plurality of clamping blocks 21 to move; and since each downward driving member 33 simultaneously presses two rotating rods 32 to move, therefore, a downward driving member 33 can synchronously drive a plurality of clamping blocks 21 on both sides to move toward a side close to each other.

[0034] Reference Figure 5In order to make the push block 34 push the clamping block 21 to move along the second direction Y more stably, in some embodiments of the present application, a guide assembly 4 is also included, and each clamping block 21 is connected to the substrate 1 through a corresponding guide assembly 4; specifically, the guide assembly 4 includes a guide bar 41 and two guide rods 42, the guide bar 41 is parallel to the third direction Z, and a guide rod 42 is fixedly connected to each end of the guide bar 41, and the guide rod 42 is parallel to the second direction Y. A guide hole 13 for the guide rod 42 to pass through is opened on the side wall of the substrate 1, and the guide rod 42 passes through the guide hole 13 and can move along the second direction Y under the guidance of the hole wall of the guide hole 13; in the second direction Y, the guide bar 41 is clamped between the clamping block 21 and the push block 34, and the clamping block 21 is fixedly connected to the guide bar 41. In the process of pushing the guide bar 41 to move, the push block 34 can push the clamping block 21 to move through the guide bar 41.

[0035] Reference Figure 6 and Figure 7 In some embodiments of the present application, a protective sleeve 5 having a material hole 51 is further included. The protective sleeve 5 is cylindrical. The material hole 51 is used to accommodate the blades. The clamping space 22 is used for inserting the protective sleeve 5 so as to fix the protective sleeve 5 through the clamping block 21 and the substrate 1. In some embodiments of the present application, after the protective sleeve 5 is inserted into the clamping space 22, if it is necessary to limit the protective sleeve 5 to a certain extent, it is only necessary to open a mounting groove 14 connected to the clamping space 22 on the substrate 1, the groove depth of the mounting groove 14 is perpendicular to the first direction X, and a limiting block 6 is inserted in the mounting groove 14, and the limiting block 6 can move in the mounting groove 14, so that the limiting end 60 of the limiting block 6 is inserted into the limiting groove 52 or passes through the limiting groove 52 and then moves to the clamping space 22; A limiting groove 52 is formed through the outer peripheral wall of the protective sleeve 5 along the first direction X. The limiting groove 52 is used for inserting the limiting block 6. After the limiting block 6 is inserted into the limiting groove 52, the groove wall of the limiting groove 52 can prevent the protective sleeve 5 from rotating. The protective sleeve 5 has a first limiting surface 521 and a first avoiding surface 522 in the limiting groove 52. The first limiting surface 521 is perpendicular to the tangent of the protective sleeve 5. An angle is formed between the first avoiding surface 522 and the first limiting surface 521. In the present disclosure, a 90° angle is formed between the first avoiding surface 522 and the first limiting surface 521. The limiting block 6 has a second limiting surface 61. After the limiting block 6 is inserted into the limiting groove 52, the first limiting surface 521 can move with the protective sleeve 5 to be parallel to the second limiting surface 61, so that the second limiting surface 61 can limit the protective sleeve 5 from rotating in the direction from the first limiting surface 521 to the second limiting surface 61. In some embodiments of the present application, an end surface of the limit block 6 close to the protective sleeve 5 is a second avoidance surface 62, and the angle formed between the second avoidance surface 62 and the first limit surface 521 is smaller than the angle between the first avoidance surface 522 and the first limit surface 521, so as to prevent the first avoidance surface 522 and the second avoidance surface 62 from contacting each other, and to prevent interference between the first avoidance surface 522 and the second avoidance surface 62.

[0036] The implementation principle of a clamping tool for processing aircraft engine blades in an embodiment of the present application is: insert the blade into the clamping space 22, and then rotate the downward driving member 33, so that the active end 321 of the rotating rod 32 is driven by the downward driving member 33 to rotate from the upper plate surface 15 to the lower plate surface 16, and at the same time, the driven end 322 of the rotating rod 32 can be rotated from the lower plate surface 16 to the upper plate surface 15 to shorten the distance between the push block 34 and the substrate 1 in the second direction Y, so that the push block 34 can push the clamping block 21 toward the substrate 1 by squeezing the guide strip 41 to clamp the blade.

[0037] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A clamping tool for machining aircraft engine blades, characterized in that: include: A substrate (1) having an upper surface (15) and a lower surface (16), wherein the surface of the substrate (1) is perpendicular to a first direction X; as well as A clamping assembly (2), the clamping assembly (2) comprising: Two clamping blocks (21) are arranged at intervals in a second direction Y, and in the second direction Y, the substrate (1) is located between the two clamping blocks (21); the clamping blocks (21) and the substrate (1) form a clamping space (22) in the second direction Y, and the depth direction of the clamping space (22) is parallel to the first direction X; the clamping block (21) is slidably connected to the clamping block (21) along the second direction Y to change the length of the clamping space (22) in the second direction Y.

2. The clamping tool for machining aero-engine blades according to claim 1, characterized in that: A first clamping groove (211) is provided on a side of the clamping block (21) close to the clamping space (22), and a second clamping groove (12) is provided on a side of the substrate (1) close to the clamping block (21), and the clamping space (22) is formed by splicing a groove wall of the first clamping groove (211) and a groove wall of the second clamping groove (12).

3. The clamping tool for machining aero-engine blades according to claim 1, characterized in that: It also includes a bidirectional drive component (3), the bidirectional drive component (3) comprising: A mounting frame (31), the mounting frame (31) being fixedly connected to the base plate (1); A rotating rod (32) having an active end (321) and a driven end (322), wherein two rotating rods (32) are provided, and the middle portion of each rotating rod (32) is rotatably connected to the mounting frame (31) via a first rotating shaft (323) corresponding thereto, and the first rotating shaft (323) is parallel to the third direction Z; the two first rotating shafts (323) are spaced apart in the second direction Y; the active ends (321) of the two rotating rods (32) are located on a side where the two first rotating shafts (323) are close to each other, and the driven ends (322) of the two rotating rods (32) are located on a side where the two first rotating shafts (323) are away from each other; a downward pressing driving member (33), the downward pressing driving member (33) being slidably connected to the base plate (1) along a first direction X, the downward pressing driving member (33) being located on a side of the rotating rod (32) close to the base plate (1), and the downward pressing driving member (33) being in contact with a side of the driven end (322) close to the base plate (1); and A push block (34), each active end (321) of the rotating rod (32) is correspondingly connected with the push block (34), and in the second direction Y, the push block (34) abuts against a side of the clamping block (21) away from the clamping space (22); The push block (34) can be adjusted between a clamping posture and a force-releasing posture along with the rotating rod (32); when the push block (34) moves from the clamping block (21) to the substrate (1) along with the rotating rod (32), the push block (34) is adjusted from the force-releasing posture to the clamping posture, and in the second direction Y, the straight-line distance between the push block (34) and the clamping space (22) gradually decreases.

4. The clamping tool for machining aero-engine blades according to claim 3, characterized in that: The push block (34) is detachably connected to the driven end (322) of the rotating rod (32).

5. The clamping tool for machining aero-engine blades according to claim 3, characterized in that: The end of the push block (34) close to the clamping block (21) is in an arc shape with an opening facing the end away from the push block (34).

6. The clamping tool for machining aero-engine blades according to claim 4, characterized in that: In the third direction Z, the clamping components (2) are distributed in plurality, and each of the rotating rods (32) is also provided with a plurality of push blocks (34), and each of the clamping blocks (21) in the clamping components (2) is correspondingly provided with a push block (34).

7. The clamping tool for machining aero-engine blades according to claim 5, characterized in that: The pressing-down driving member (33) is penetrated through the base plate (1) along the first direction X, and the pressing-down driving member (33) is threadably connected to the base plate (1), and one end of the pressing-down driving member (33) close to the driven end (322) of the rotating rod (32) is capable of contacting the driven end (322) of the rotating rod (32).

8. A clamping tool for machining aero-engine blades according to any one of claims 1 to 7, characterized in that: It also comprises a protective sleeve (5) having a material hole (51), wherein the protective sleeve (5) is cylindrical, the material hole (51) is used to accommodate blades, and the clamping space (22) is used for inserting the protective sleeve (5).

9. The clamping tool for machining aero-engine blades according to claim 8, characterized in that: Also includes: a limit block (6) having a limit end (60), the limit block (6) being connected to the base plate (1); the limit block (6) being arranged on the side of at least one of the clamping spaces (22); The outer peripheral wall of the protective sleeve (5) is provided with a limiting groove (52), the limiting groove (52) penetrates the protective sleeve (5) along the first direction X, and the limiting groove (52) is used for the limiting block (6) to be inserted.

10. The clamping tool for machining aero-engine blades according to claim 9, characterized in that: The protective sleeve (5) has a first limiting surface (521) and a first avoiding surface (522) in the limiting groove (52), the first limiting surface (521) is perpendicular to a tangent line of the protective sleeve (5), and an angle is formed between the first avoiding surface (522) and the first limiting surface (521); The limiting end (60) of the limiting block (6) has a second limiting surface (61) and a second avoiding surface (62), the distance between the second limiting surface (61) and the second avoiding surface (62) gradually decreases toward one side of the protective sleeve (5), and the angle between the second limiting surface (61) and the second avoiding surface (62) is smaller than the angle formed between the first avoiding surface (522) and the first limiting surface (521); The first limiting surface (521) can rotate along with the protective sleeve (5) to a position in contact with and parallel to the second limiting surface (61).

Images