Self-centering clamp and graphite crucible secondary machining equipment with self-centering clamp

Abstract

The utility model relates to a self-centering clamp and graphite crucible secondary machining equipment with the same, and relates to the technical field of graphite crucible machining, the self-centering clamp comprises a shell, a first clamping assembly and a second clamping assembly, a first end face is provided with a first sliding groove and a second sliding groove which are arranged in a crossed mode, and a second end face is provided with a second sliding groove; the first clamping assembly moves in the length direction of the first sliding groove, the two ends, located in the center of the first end face, of the first clamping assembly can be close to or away from the center of the first end face simultaneously, and the second clamping assembly moves in the length direction of the second sliding groove, and the two ends, located in the center of the first end face, of the second clamping assembly can be close to or away from the center of the first end face simultaneously. The utility model further provides secondary machining equipment of the graphite crucible. The secondary machining equipment comprises a lathe bed and the self-centering clamp. An existing four-jaw chuck is improved, four-jaw simultaneous linkage of the four-jaw chuck is changed into two-way independent linkage, and the problems that an existing two-way independent linkage clamp is complex in structure and high in manufacturing cost are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of graphite crucible processing, and more specifically, to a self-centering fixture applicable to graphite crucibles and a secondary processing device for graphite crucibles with the same. Background Technique

[0002] In the prior art, a crucible is usually a device used to hold metal during high-temperature smelting. During the manufacturing process of the crucible, the cylindrical structure thereof is prone to deformation during the firing process. After deformation, it presents an elliptical shape at the opening position. In the later stage, it is necessary to turn the deformed part of the crucible. During the turning process, a self-centering fixture is required to hold the crucible and position the crucible at the same time.

[0003] Traditional two-way self-centering fixtures are divided into three-jaw and four-jaw fixtures. The four-jaw fixtures can be further divided into fixtures with two-way synchronous linkage and fixtures with two-way independent linkage. The fixture with two-way synchronous linkage is a structure in which a threaded disc drives the movement of the jaws, approaching and separating simultaneously in two directions. The fixture with two-way independent linkage is a structure of a gear rack or a screw rod, and the two directions can move independently.

[0004] However, during use, the three-jaw self-centering fixture will generate eccentricity when clamping the characteristics of elliptical parts. The fixture with two-way synchronous linkage cannot clamp the irregular characteristics on the surface of the workpiece, such as rectangles or ellipses. And for the fixture with two-way independent linkage, due to its small demand, its price is inflated and its structure is complex.

[0005] Therefore, how to provide a new two-way self-centering fixture, which has the characteristics of low cost and is improved on the existing mature clamping scheme to achieve the purpose of clamping the irregular characteristics on the surface of the workpiece, is an urgent problem to be solved by those skilled in the art. Content of the Utility Model

[0006] In view of this, the utility model provides a self-centering fixture and a secondary processing device for graphite crucibles with the same, aiming to solve the above technical problems.

[0007] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0008] A self-centering fixture, comprising:

[0009] A housing, the housing has a first end face, the first end face is provided with a first chute and a second chute, the first chute and the second chute are arranged crosswise and both pass through the center of the first end face;

[0010] The first clamping assembly, the first clamping assembly includes a first clamping part and a first driving part. The number of the first clamping parts is two, and the two first clamping parts are symmetrically distributed on both sides of the center of the first end face and are both slidably connected to the first sliding groove. The first driving part includes a fixed block and a bidirectional screw. The fixed block is fixed at the intersection of the first sliding groove and the second sliding groove. The fixed block is provided with a mounting hole along the length direction of the first sliding groove. The middle part of the bidirectional screw is rotatably connected in the mounting hole. The rod bodies of the bidirectional screw on both sides of the fixed block have opposite threads and are respectively helically connected to the two first clamping parts;

[0011] The second clamping assembly, the second clamping assembly includes a second clamping part and a second driving part. The number of the second clamping parts is two, and the two second clamping parts are symmetrically distributed on both sides of the center of the first end face and are slidably connected to the second sliding groove. The second driving part is rotatably connected inside the housing, and a spiral groove is provided on a surface of the second driving part close to the first end face. The second clamping part is in meshing transmission with the spiral groove.

[0012] Through the above technical solutions, the utility model avoids the defect of the complex structure of the two-way self-centering fixture in the prior art. On the existing two-way synchronous linkage fixture, the original structure with an internal second driving part is retained. Through the cooperation of spiral transmission, the two second clamping parts can be driven to approach and separate. On this basis, another set of clamping assemblies adopts the cooperation of a bidirectional screw and a fixed block. Only by turning the bidirectional screw can the two first clamping parts be directly driven to approach and separate. This self-centering fixture can be directly improved on the basis of the original structure, with simple structure, low transformation cost and stable structure.

[0013] Preferably, in the above self-centering fixture, the first clamping part includes a first slider. One side of the first slider is slidably connected to the first sliding groove, and a first clamping block is fixedly connected to the other side of the first slider. A through threaded hole is provided on the first clamping block, and the threaded hole is helically connected to the bidirectional screw.

[0014] Preferably, in the above self-centering fixture, the second clamping part includes a second slider. One side of the second slider has spiral teeth meshing with the spiral groove, and the second slider is slidably connected to the second sliding groove. A second clamping block is fixedly connected to the other side.

[0015] The beneficial effects of the above two technical solutions are as follows: The first slider and the first clamping block are detachably connected, and the second slider and the second clamping block are detachably connected. Different first clamping blocks and second clamping blocks can be replaced according to different needs to realize the clamping of the outer wall or inner hole of the workpiece.

[0016] Preferably, in the above self-centering fixture, the second driving part includes a driving disk and a bevel gear. An annular tooth groove is formed on a surface of the driving disk away from the first end face, and a bevel gear meshing with the annular tooth groove is rotatably connected to the side wall of the housing.

[0017] The beneficial effects of the above technical solutions are as follows: The transmission direction of the driving disk is changed by the bevel gear. The bevel gear, as the power input end of the second driving part, is rotatably connected to the side wall of the housing, which is convenient for power input.

[0018] Preferably, in the above self-centering fixture, both ends of the first clamping block and the second clamping block away from the center of the first end face are provided with clamping claws. The length direction of the clamping claws is perpendicular to the first end face, and a groove is formed on the side of the middle position of the clamping claws along their length direction and away from the center of the first end face.

[0019] The beneficial effects of the above technical solutions are as follows: The clamping claws can clamp the workpiece. The grooves can reduce the contact area between the clamping claws and the graphite crucible, increase the clamping force, and at the same time avoid the convex defects on the surface of the graphite crucible, resulting in insecure clamping between the clamping claws and the graphite crucible.

[0020] Preferably, in the above self-centering fixture, the housing is formed by butting a first half housing and a second half housing. Corresponding frustum cones are fixed on the inner bottom surfaces of the first half housing and the second half housing. A first fitting part is radially formed at the butting gap of the two, and a second fitting part corresponding to the first fitting part is radially formed at the butting gap of the first half housing and the second half housing. One end of the bevel gear is rotatably connected to the first fitting part, and the other end is rotatably connected to the second fitting part.

[0021] The beneficial effects of the above technical solutions are as follows: By dividing the housing into a first half housing and a second half housing, it is convenient for the assembly of the driving disk and the bevel gear. The two ends of the bevel gear are respectively rotatably connected to the first fitting part and the second fitting part, improving the structural stability.

[0022] Preferably, in the above self-centering fixture, tooth teeth are arranged at the middle positions of both ends of the bevel gear for meshing transmission with the annular tooth groove, and an inner square groove is formed at one end of the bevel gear and is exposed outside the side wall of the housing.

[0023] The beneficial effects of the above technical solutions are as follows: The bevel gear has tooth teeth for meshing transmission with the annular tooth groove, improving the transmission efficiency. And a groove is formed at the end of the bevel gear exposed outside the housing, providing a force application point for the rotation of the bevel gear, and the driving disk can be more conveniently driven through the bevel gear.

[0024] Preferably, in the above self-centering fixture, rotating blocks are fixed at both ends of the bidirectional screw.

[0025] The beneficial effects of the above technical solution are: providing a force point for the rotation of the bidirectional screw, and the bidirectional screw can be driven more conveniently by the rotating block.

[0026] The utility model also provides a secondary processing device for a graphite crucible, comprising: a bed and the above-mentioned self-centering fixture;

[0027] One end of the bed is rotatably connected to a rotating part, and an ejector base is slidably connected to the bed, the sliding direction of the ejector base corresponds to the rotating part, and the ejector base is rotatably connected to a side of the rotating part.

[0028] The side of the housing facing away from the first end surface is fixed to the rotation output end of the rotating part.

[0029] Through the above technical scheme, the utility model positions and supports the bottom of the graphite crucible by the ejector pin, and then clamps the open end of the graphite crucible by the self-centering clamp, thereby ensuring the stability of the graphite crucible during the processing. The ejector pin base is slidably connected to the bed, and different distances can be adjusted according to graphite crucibles of different sizes.

[0030] Preferably, in the above-mentioned secondary processing equipment for graphite crucible, one end of the ejector pin facing the rotating part is a pointed end.

[0031] The beneficial effects of the above technical solution are: the cutting-edge design facilitates the positioning of the workpiece, ensuring that the workpiece can always maintain a stable position and rotation axis during the processing, preventing the workpiece from shaking or offsetting, thereby ensuring the accuracy and quality of the processing

[0032] It can be seen from the above technical solutions that, compared with the prior art, the utility model discloses a self-centering fixture and a secondary processing device for a graphite crucible having the same, which has the following beneficial effects:

[0033] 1. The first clamping assembly and the second clamping assembly of the utility model move independently, and parts with elliptical features or parts that are easily deformed during processing can be better clamped or clamped, and during the clamping process, the center of the elliptical feature is always located at the center of the first end face;

[0034] 2. The self-centering clamp of the utility model is modified on the basis of the existing two-way synchronous linkage clamp, and the first clamping component is also processed and modified on its existing structure, which has a simple structure, low modification cost and stable structure;

[0035] 3. The first clamping block and the first sliding block, as well as the second clamping block and the second sliding block of the utility model are detachably connected, and different clamping blocks can be replaced according to different requirements to achieve clamping of the outer wall or inner hole of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic perspective view of the self-centering fixture provided by the present utility model;

[0037] Figure 2 Schematic perspective view of the first clamping assembly provided by the present utility model;

[0038] Figure 3 Schematic perspective view of the second clamping assembly provided by the present utility model;

[0039] Figure 4 Schematic perspective view of the drive disk provided by the present utility model;

[0040] Figure 5 is Figure 4 schematic perspective view of the other side of;

[0041] Figure 6 Top view of the housing provided by the present utility model;

[0042] Figure 7 is Figure 6 B-B sectional view of;

[0043] Figure 8 Schematic perspective view of the bevel gear provided by the present utility model;

[0044] Figure 9 Assembly schematic diagram of the bed body and the self-centering fixture provided by the present utility model;

[0045] Figure 10 Schematic perspective view of the secondary processing equipment of the graphite crucible provided by the present utility model;

[0046] Figure 11 Schematic perspective view of the graphite crucible provided by the present utility model.

[0047] Wherein:

[0048] 1 - Bed body; 2 - Self-centering fixture; 3 - Graphite crucible; 11 - Rotating part; 12 - Thimble base; 21 - Housing; 22 - First clamping assembly; 23 - Second clamping assembly; 123 - Thimble; 211 - First half housing; 212 - Second half housing; 213 - First mating part; 214 - Second mating part; 221 - First clamping part; 222 - First driving part; 231 - Second clamping part; 232 - Second driving part; 2211 - First slider; 2212 - First clamping block; 2200 - Claw; 2221 - Fixed block; 2222 - Bidirectional screw; 2202 - Rotating block; 2311 - Second slider; 2312 - Second clamping block; 2321 - Drive disk; 2322 - Bevel gear; 2300 - Tooth; 2301 - Spiral groove; 2302 - Annular tooth groove. Detailed implementation manners

[0049] The principles and features of the present utility model will be described below in conjunction with the accompanying drawings. The examples given are only for explaining the present utility model and are not intended to limit the scope of the present utility model.

[0050] Embodiment 1:

[0051] Referring to the attached Figures 1-4 , an embodiment of the present invention discloses a self-centering fixture, including:

[0052] A housing 21, the housing 21 has a first end face, the first end face is provided with a first chute and a second chute, the first chute and the second chute are arranged crosswise and both pass through the center of the first end face;

[0053] A first clamping assembly 22, the first clamping assembly 22 includes a first clamping portion 221 and a first driving portion 222. The number of the first clamping portions 221 is two, and the two first clamping portions 221 are symmetrically distributed on both sides of the center of the first end face and are both slidably connected to the first chute. The first driving portion 222 includes a fixed block 2221 and a bidirectional screw 2222. The fixed block 2221 is fixed at the intersection of the first chute and the second chute. The fixed block 2221 is provided with a mounting hole along the length direction of the first chute. The middle part of the bidirectional screw 2222 is rotatably connected in the mounting hole. The rod bodies of the bidirectional screw 2222 on both sides of the fixed block 2221 have opposite threads and are respectively helically connected to the two first clamping portions 221;

[0054] A second clamping assembly 23, the second clamping assembly 23 includes a second clamping portion 231 and a second driving portion 232. The number of the second clamping portions 231 is two, and the two second clamping portions 231 are symmetrically distributed on both sides of the center of the first end face and are slidably connected to the second chute. The second driving portion 232 is rotatably connected inside the housing 21, and a spiral groove 2301 is provided on a surface thereof close to the first end face. The second clamping portion 231 is meshed and driven with the spiral groove 2301.

[0055] In this embodiment, a threaded hole is provided around the center of the first end face of the housing 21, and a bolt mounting hole is provided on the fixed block 2221. The fixed block 2221 is fixedly connected to the housing 21 by bolts.

[0056] In this embodiment, an annular boss is provided at the center position of the first end face inside the mounting hole. The fixed block 2221 is divided into upper and lower parts. An annular groove matching the annular boss is provided in the radial direction at the center of the bidirectional screw 2222. Thus, the bidirectional screw 2222 can be more conveniently installed in the mounting hole, and the movement of the bidirectional screw 2222 in the axial direction of the mounting hole is restricted.

[0057] To further optimize the above technical solution, rotating blocks 2202 are fixed to both ends of the bidirectional screw 2222.

[0058] In this embodiment, the rotating block 2202 has a structure with an external square, external hexagon, internal square, or internal hexagon.

[0059] See the appendix Figure 2 , the first clamping portion 221 includes a first slider 2211. One side of the first slider 2211 is slidably connected to the first chute, and a first clamping block 2212 is fixedly connected to the other side of the first slider 2211. A through threaded hole is formed in the first clamping block 2212, and the threaded hole is in threaded connection with the bidirectional screw 2222.

[0060] In this embodiment, the first slider 2211 is processed on the basis of the original claw of the existing bidirectional synchronous linkage fixture. The spiral teeth that cooperate with the driving disc on the original claw are removed by processing, and a groove and a threaded hole that are positioned and matched with the first clamping block 2212 are processed on the other side where the spiral teeth are removed. The first clamping block 2212 and the first slider 2211 are fixedly connected by bolts.

[0061] See the appendix Figure 3 , the second clamping portion 231 includes a second slider 2311. One side of the second slider 2311 has spiral teeth that mesh with the spiral groove 2301, and the second slider 2311 is slidably connected to the second chute, and a second clamping block 2312 is fixedly connected to the other side.

[0062] In this embodiment, the second slider 2311 is processed on the basis of the original claw of the existing bidirectional synchronous linkage fixture. A groove and a threaded hole that are positioned and matched with the second clamping block 2312 are processed on the other side. The second clamping block 2312 and the second slider 2311 are fixedly connected by bolts. Thus, the technical effect of bidirectional independent linkage can be achieved through simple processing on the existing structure, which has the characteristics of simple structure, low cost, and stable structure.

[0063] In this embodiment, the threaded hole is symmetric with respect to the groove for positioning and matching. Thus, the directions of the first clamping block 2212 and the second clamping block 2312 can be reversed to clamp the outer wall or inner hole of the workpiece.

[0064] See the appendix Figure 3 and the appendix Figure 5 , the second driving portion 232 includes a driving disc 2321 and a bevel gear 2322. An annular tooth groove 2302 is formed on a surface of the driving disc 2321 away from the first end face, and a bevel gear 2322 that meshes with the annular tooth groove 2302 is rotatably connected to the side wall of the housing 21.

[0065] In this embodiment, a plurality of bevel gears 2322 are evenly distributed on the side wall of the housing 21 in the radial direction of the drive disk 2321. Thus, the second clamping part can be adjusted more conveniently at different angles.

[0066] To further optimize the above technical solution, both ends of the first clamping block 2212 and the second clamping block 2312 away from the center of the first end face are provided with claw teeth 2200. The length direction of the claw teeth 2200 is perpendicular to the first end face, and a groove is provided on one side of the middle position of the claw teeth 2200 along its length direction and away from the center of the first end face.

[0067] In this embodiment, for the end faces on both sides of the groove, the end face close to the first end face is higher than the end face away from the first end face. Thus, the height difference between the two end faces can limit the axial direction of the graphite crucible 3.

[0068] See the attached Figure 6 and the attached Figure 7 , the housing is formed by the mating of a first half housing 211 and a second half housing 212. Corresponding truncated cones are fixed on the inner bottom surfaces of the first half housing 211 and the second half housing 212. A first fitting portion 213 is radially provided at the gap formed after the mating of the two truncated cones. A second fitting portion 214 corresponding to the first fitting portion 213 is radially provided at the gap formed after the mating of the first half housing 211 and the second half housing 212. One end of the support shaft body of the bevel gear is rotatably connected to the first fitting portion 213, and the other end is rotatably connected to the second fitting portion 214.

[0069] In this embodiment, both the first half housing 211 and the second half housing 212 are cylindrical housings. After the openings of the first half housing 211 and the second half housing 212 are mated, they are then fastened by bolts.

[0070] See the attached Figure 8 , tooth teeth 2300 are arranged at the middle positions of both ends of the bevel gear and meshed with the annular tooth groove 2302 for transmission. An inner square groove is provided at one end of the bevel gear 2322 and is exposed outside the side wall of the housing 21.

[0071] The specific principle and usage method of the self-centering fixture provided in this embodiment are as follows:

[0072] 1. Rotate the rotating block 2202 to drive the bidirectional screw 2222 to rotate, and the first clamping parts 221 on both sides of the fixed block 2221 approach or move away from the center of the first end face simultaneously;

[0073] 2. Rotate the bevel gear 2322 on the side wall of the housing 21 to drive the drive disk 2321 to rotate, and the second clamping parts 231 meshed with the spiral groove 2301 in the drive disk 2321 approach or move away from the center of the first end face simultaneously.

[0074] Embodiment 2:

[0075] See attached Figures 9-11 , the embodiment of the present invention discloses a secondary processing equipment for graphite crucible, comprising: a bed 1 and the self-centering fixture in embodiment 1;

[0076] One end of the bed 1 is rotatably connected to a rotating part 11, and an ejector base 12 is slidably connected to the bed 1. The sliding direction of the ejector base 12 corresponds to the rotating part 11, and the ejector base 12 is rotatably connected to one side of the rotating part 11 with an ejector 123;

[0077] The side of the housing 21 facing away from the first end surface is fixed to the rotation output end of the rotating part 11 .

[0078] In order to further optimize the above technical solution, the end of the ejector pin 123 facing the housing 21 is a pointed end.

[0079] The specific method of using the secondary processing equipment of the graphite crucible provided in this embodiment is:

[0080] 1. Preparation: Rotate the rotating block 2202 to drive the bidirectional screw 2222 to rotate, so that the first clamping parts 221 on both sides of the fixed block 2221 are close to the center of the first end surface at the same time;

[0081] 2. Preparation: Rotate the bevel gear 2322 on the side wall of the housing 21 to drive the driving disk 2321, and the second clamping portion 231 that is meshed with the spiral groove 2301 in the driving disk 2321 is close to the center of the first end surface at the same time;

[0082] 3. Preparation: slide the ejector base 12 away from the rotating part 11;

[0083] 4. Hoisting: hoist the graphite crucible 3 so that the center of the open end of the graphite crucible 3 is roughly located at the center of the first end surface, and the axial direction of the graphite crucible 3 is parallel to the length direction of the bed 1;

[0084] 5. Pre-tighten, rotate the rotating block 2202, drive the bidirectional screw 2222 to rotate, and the first clamping parts 221 on both sides of the fixed block 2221 move away from the center of the first end surface at the same time, until the claws 2200 contact the inner wall of the graphite crucible 3;

[0085] 6. Pre-tighten, rotate the bevel gear 2322 on the side wall of the housing 21, drive the driving disk 2321 to rotate, and the second clamping portion 231 meshing with the spiral groove 2301 in the driving disk 2321 is moved away from the center of the first end surface at the same time, until the claw 2200 contacts the inner wall of the graphite crucible 3;

[0086] 7. Tighten, slide the ejector base 12 close to the rotating part 11, until the ejector 123 pushes the graphite crucible 3, and the end surface of the opening end of the graphite crucible 3 contacts the surface of the groove of the claw 2200 close to the first end surface;

[0087] 8. Tighten it to keep a certain clamping force between the clamping jaw 2200 and the graphite crucible 3, and lock the ejector pin base 12.

[0088] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A self-centering fixture, characterized in that, Comprising: A housing (21), the housing (21) having a first end face, the first end face being provided with a first sliding groove and a second sliding groove, the first sliding groove and the second sliding groove being arranged crosswise and both passing through the center of the first end face; A first clamping assembly (22), the first clamping assembly (22) including a first clamping portion (221) and a first driving portion (222), the number of the first clamping portions (221) being two, the two first clamping portions (221) being symmetrically distributed on both sides of the center of the first end face and both being slidably connected to the first sliding groove, the first driving portion (222) including a fixed block (2221) and a bidirectional screw (2222), the fixed block (2221) being fixed at the intersection of the first sliding groove and the second sliding groove, the fixed block (2221) being provided with a mounting hole along the length direction of the first sliding groove, the middle of the bidirectional screw (2222) being rotatably connected in the mounting hole, the rod bodies of the bidirectional screw (2222) on both sides of the fixed block (2221) having opposite threads and being respectively helically connected to the two first clamping portions (221); A second clamping assembly (23), the second clamping assembly (23) including a second clamping portion (231) and a second driving portion (232), the number of the second clamping portions (231) being two, the two second clamping portions (231) being symmetrically distributed on both sides of the center of the first end face and being slidably connected to the second sliding groove, the second driving portion (232) being rotatably connected inside the housing (21), and a spiral groove (2301) being provided on a surface of the second driving portion (232) close to the first end face, the second clamping portion (231) being in meshing transmission with the spiral groove (2301).

2. The self-centering fixture according to claim 1, wherein The first clamping portion (221) includes a first slider (2211), one side of the first slider (2211) being slidably connected to the first sliding groove, a first clamping block (2212) being tightly connected to the other side of the first slider (2211), a through threaded hole being provided in the first clamping block (2212), and the threaded hole being helically connected to the bidirectional screw (2222).

3. A self-centering fixture according to claim 2, characterized in that, The second clamping portion (231) includes a second slider (2311), one side of the second slider (2311) having spiral teeth meshing with the spiral groove (2301), the second slider (2311) being slidably connected to the second sliding groove, and a second clamping block (2312) being tightly connected to the other side.

4. The self-centering fixture according to claim 3, characterized in that, The second driving portion (232) includes a driving disk (2321) and a bevel gear (2322), an annular tooth groove (2302) being provided on a surface of the driving disk (2321) away from the first end face, and a bevel gear (2322) meshing with the annular tooth groove (2302) being rotatably connected to the side wall of the housing (21).

5. The self-centering fixture according to claim 4, wherein One end of each of the first clamping block (2212) and the second clamping block (2312) away from the center of the first end face is provided with a claw (2200), and a groove is provided on a side of the claw (2200) away from the center of the first end face.

6. The self-centering fixture according to claim 5, characterized in that, The shell is composed of a first half shell (211) and a second half shell (212) matched together. The inner bottom surfaces of the first half shell (211) and the second half shell (212) are both fixed with mutually corresponding frustums. A first matching portion (213) is radially opened at the gap between the two frustums after the two frustums are matched together. A second matching portion (214) corresponding to the first matching portion (213) is radially opened at the gap between the first half shell (211) and the second half shell (212) after the first half shell (211) and the second half shell (212) are matched together. One end of the support shaft of the bevel gear is rotatably connected to the first matching portion (213), and the other end is rotatably connected to the second matching portion (214).

7. The self-centering fixture according to claim 6, characterized in that, Teeth (2300) are arranged in the middle of both ends of the bevel gear to mesh with the annular tooth groove (2302) for transmission, and an inner square groove is formed at one end of the bevel gear (2322) and is exposed on the side wall of the housing (21).

8. The self-centering fixture according to claim 1, wherein Rotating blocks (2202) are fixed to both ends of the bidirectional screw (2222).

9. A secondary processing device for a graphite crucible, characterized in that, include: A bed (1) and a self-centering fixture as claimed in any one of claims 1 to 8; One end of the bed (1) is rotatably connected to a rotating part (11), and a thimble base (12) is slidably connected to the bed (1), the sliding direction of the thimble base (12) corresponds to the rotating part (11), and the thimble base (12) is rotatably connected to a side of the rotating part (11); The side of the housing (21) facing away from the first end surface is fixed on the rotation output end of the rotating part (11).

10. The secondary processing equipment for a graphite crucible according to claim 9, characterized in that, One end of the ejector pin (123) facing the housing (21) is a pointed end.

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