Support plate inner cavity mounting hole machining clamp and machining method

Abstract

The invention discloses a support plate inner cavity mounting hole machining clamp and method, and the clamp comprises a bottom plate which is used as a structure support; the first supporting assembly is arranged on the bottom plate and used for being arranged in the workpiece in a penetrating mode and supporting a supporting part of an inner ring of the workpiece, and positioning grooves matched with the circumferential distribution positions and the height positions of the supporting plates are formed in the first supporting assembly in the axial direction; the pressing assembly is used for being pressed on the supporting part of the inner ring of the workpiece and connected with the first supporting piece so as to press and fix the workpiece; the second supporting assembly is arranged on the bottom plate and used for supporting a supporting part of an outer ring of the workpiece, and the second supporting assembly is provided with a positioning structure matched with the circumferential distribution position and the height position of each positioning groove; the positioning piece is arranged on the positioning structure in a penetrating mode in the radial direction, and the positioning piece sequentially comprises a first positioning section matched with the width of the positioning groove, a second positioning section matched with the size of a cutter used for machining the mounting hole of the inner cavity of the supporting plate and a third positioning section matched with the inner diameter of the positioning structure in the axial direction.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengines, and in particular, to a support plate inner cavity mounting hole processing fixture. In addition, the present invention also relates to a support plate inner cavity mounting hole processing method comprising the support plate inner cavity mounting hole processing fixture. Background Art

[0002] Some castings of aircraft engine parts require oil and gas pipe mounting holes to be processed in the inner cavity of the support plate. The oil and gas pipes are connected to the turbine casing through the outside of the mounting holes. The inner ring is assembled with the power turbine bearing seat, which plays a connecting and load-bearing role in the engine. Typical parts include the bearing seat bracket assembly, load-bearing casing assembly, interstage guide assembly, transition section assembly, etc.

[0003] Take the processing of the inner cavity mounting hole of the support plate of a certain type of bearing seat bracket assembly as an example. The bearing seat bracket assembly is an important component of a certain type of engine. The material of the part is cast high-temperature alloy K438, which has high hardness and poor cutting performance and is a difficult-to-process material. Its inner ring is assembled with the power turbine bearing seat, and the outer circle is assembled with the turbine casing. The inner and outer rings are connected by 4 support plates. The external air pipe penetrates from the support plate and is connected to the power seat. The 4 support plates are directly formed by casting. The diameter of the mounting hole in the support plate is φ12, and the gap with the inner wall of the support plate is only 0.2~0.5. Due to the large deviation in the angular relationship between the blank angular hole and the support plate, when aligning the blank angular hole to process the φ12 hole, the inner wall of the support plate will be processed, resulting in a thinning of the support plate wall thickness, and there are processing marks on the blank surface, and the deviation rate is 100%. Due to the deviation in the casting of the blank support plate, the inner wall of the support plate is easily scratched during the processing of the mounting hole. The main reasons are: there is an angular deviation between the angular hole of the blank and the 4 blank support plates; the gap between the machined φ12 hole and the inner wall of the support plate is too small; the angular position deviation between the 4 cast support plates is large. Summary of the invention

[0004] The present invention provides a support plate inner cavity mounting hole processing fixture and processing method, so as to solve the technical problem in the prior art that when processing the oil and gas pipe mounting holes in the support plate inner cavity of some aircraft engine castings, there is too small gap and large angular deviation, which makes the support plate inner cavity easy to be scratched during processing.

[0005] According to one aspect of the present invention, a fixture for machining mounting holes in a support plate inner cavity is provided, which is applied to machining a workpiece having a support plate inner cavity in an aero-engine, comprising:

[0006] Base plate, used as structural support;

[0007] A first support assembly is arranged on the bottom plate and is used to penetrate the workpiece and support the support portion of the inner ring of the workpiece. The first support assembly is provided with a positioning groove along the axial direction to match the circumferential distribution position and height position of each support plate;

[0008] A clamping assembly, used for being pressed onto the support portion of the inner ring of the workpiece and connected to the first support member to clamp and fix the workpiece;

[0009] A second supporting assembly is disposed on the bottom plate and is used to support the supporting portion of the outer ring of the workpiece. The second supporting assembly is provided with a positioning structure that matches the circumferential distribution position and height position of each positioning groove;

[0010] The positioning piece is radially penetrated in the positioning structure, and the positioning piece includes a first positioning section matching the width of the positioning groove, a second positioning section matching the size of a tool for machining the inner cavity mounting hole of the support plate, and a third positioning section matching the inner diameter of the positioning structure in sequence along the axial direction.

[0011] As a further improvement of the above technical solution, the clamping assembly includes a pressure plate, a stud bolt and a first nut. The pressure plate is pressed onto the supporting portion of the inner ring of the workpiece. The stud bolt passes through the pressure plate and is threadedly connected to the first supporting assembly. The first nut is threadedly connected to the stud bolt to lock the pressure plate.

[0012] As a further improvement of the above technical solution, the processing fixture includes a first cylindrical pin respectively penetrated through the pressure plate and the first supporting assembly.

[0013] As a further improvement of the above technical solution, the positioning structure includes a fixing hole opened in the second supporting assembly and a bushing arranged in the fixing hole, and the inner diameter of the bushing matches the outer diameter of the third positioning section.

[0014] As a further improvement of the above technical solution, the matching clearance between the first positioning section and the positioning groove is 0.002-0.012 mm, and the matching clearance between the third positioning section and the positioning structure is 0.01-0.0275 mm.

[0015] As a further improvement of the above technical solution, a support block is provided on the top of the second support assembly, and the support block is used to cooperate with the support portion of the outer ring of the workpiece.

[0016] As a further improvement of the above technical solution, as a further improvement of the above technical solution, both ends of the positioning groove are respectively provided with expansion structures with a size larger than the width of the positioning groove.

[0017] As a further improvement of the above technical solution, the diameter of the third positioning segment is larger than the diameter of the second positioning segment, and the diameter of the first positioning segment is smaller than the diameter of the second positioning segment.

[0018] According to another aspect of the present invention, a method for machining a support plate inner cavity mounting hole is also provided, which includes the above-mentioned support plate inner cavity mounting hole machining fixture, and the machining method includes:

[0019] S1. Clamp the workpiece and align the fixture;

[0020] S2. Processing the angle hole of the workpiece installation edge;

[0021] S3. Insert the positioning member into the corresponding positioning groove through the positioning structure;

[0022] S4. Rotate the workpiece in the first direction until the inner cavity of the support plate is close to the positioning piece, and set the pressure gauge on one side of the support plate to zero. Rotate the workpiece in the second direction until the inner cavity of the support plate is close to the positioning piece and then read the pressure gauge value. Rotate the workpiece in the first direction to half of the pressure gauge value.

[0023] S5. Clamp the workpiece and align the fixture;

[0024] S6. Process the mounting holes in the inner cavity of the support plate.

[0025] As a further improvement of the above technical solution:

[0026] The workpiece has four support plate cavities, and step S3 includes:

[0027] S31. Insert the positioning members into the corresponding positioning grooves by the positioning structures in the X-direction and Y-direction directions. If the positioning members can be inserted, proceed to step S4. If there are positioning members that cannot be inserted into the positioning grooves, proceed to step S32.

[0028] S32. Adjust the position of the workpiece so that the positioning slot that cannot be inserted is adjusted to the positive X direction, and insert the positioning piece into the corresponding positioning slot again from the negative X direction and the Y direction. If the positioning piece can be inserted, go to step S4. If there is a positioning piece that cannot be inserted, the angular deviation of the workpiece support plate is too large. Replace the workpiece and go to step S1.

[0029] The present invention has the following beneficial effects:

[0030] The machining fixture supports the inner ring and outer ring of the workpiece respectively by respectively setting a first supporting assembly and a second supporting assembly, and the clamping assembly is clamped and fixed to the first supporting assembly to position and clamp the workpiece; by setting a positioning groove on the first supporting assembly and a positioning structure on the second supporting assembly, the circumferential distribution position of each positioning groove and the circumferential distribution position of each positioning structure are matched with the distribution position of the inner cavity of the support plate, and the height position is also matched; the positioning groove and the positioning structure perform two-point positioning of the positioning member to ensure the angular position accuracy of the positioning member, and the second positioning section of the positioning member simulates the insertion of the machining tool into the inner cavity of the support plate. When each positioning member can be smoothly inserted into the inner cavity of the support plate to the positioning groove, it can be judged that the machining tool will not process the inner wall of the inner cavity of the support plate in actual machining, thereby avoiding scratches on the workpiece, ensuring that the problem of poor machining appearance quality is eliminated before part machining, improving the machining preparation and alignment efficiency, and shortening the workpiece machining time.

[0031] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 is a structural schematic diagram of a processing fixture according to a preferred embodiment of the present invention;

[0034] Figure 2 yes Figure 1 G-direction cross-sectional view;

[0035] Figure 3 is a schematic diagram of the workpiece structure of the first embodiment of the present invention;

[0036] Figure 4 yes Figure 3 A-direction sectional view;

[0037] Figure 5 This is a process diagram of step S3 of the first embodiment of the present invention;

[0038] Figure 6 This is the clamping scheme diagram of comparative example 1;

[0039] Figure 7 This is a positioning scheme diagram for comparative example 1;

[0040] Figure 8 This is the clamping scheme diagram of comparative example 2;

[0041] Fig. 9 This is a positioning scheme diagram for comparative example 2.

[0042] Legend:

[0043] 1. Base plate; 11. Lifting ring; 12. First screw; 13. Second cylindrical pin; 2. First supporting assembly; 21. Positioning groove; 3. Second supporting assembly; 31. Bushing; 32. Support block; 33. Second screw; 4. Positioning piece; 41. First positioning section; 42. Second positioning section; 43. Third positioning section; 5. Press plate; 6. Stud bolt; 7. First nut; 8. First cylindrical pin; 9. Second nut. DETAILED DESCRIPTION

[0044] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0045] like Figures 1 to 5 As shown, the support plate inner cavity mounting hole processing fixture of this embodiment is applied to the processing of a workpiece having a support plate inner cavity in an aero-engine, and includes:

[0046] Base plate 1, used as a structural support;

[0047] The first support assembly 2 is arranged on the bottom plate 1 and is used to penetrate the workpiece and support the inner ring of the workpiece. The first support assembly 2 is provided with a positioning groove 21 along the axial direction to match the circumferential distribution position and height position of each support plate;

[0048] A clamping assembly, used for being pressed onto the support portion of the inner ring of the workpiece and connected to the first support member to clamp and fix the workpiece;

[0049] The second support group 3 pieces are arranged on the bottom plate 1 and are used to support the support portion of the outer ring of the workpiece. The second support group 3 pieces are provided with positioning structures matching the circumferential distribution position and height position of each positioning groove 21;

[0050] The positioning member 4 is radially penetrated in the positioning structure, and the positioning member 4 includes a first positioning section 41 matching the width of the positioning groove 21, a second positioning section 42 matching the size of a tool for machining the inner cavity mounting hole of the support plate, and a third positioning section 43 matching the inner diameter of the positioning structure.

[0051] Among them, the first support assembly 2 includes a cylindrical first support member, the top of the first support member is closed to facilitate the connection of the clamping assembly; the second support assembly 3 includes a cylindrical second support member; the bottom plate 1 is symmetrically provided with lifting rings 11 for lifting and transportation; the bottom plate 1 is connected to the first support member and the second support member respectively by a first screw 12, and a second cylindrical pin 13 is provided to achieve positioning; it should be understood that the positioning structure and the layout position of the positioning groove 21 match the theoretical design position of the support plate rather than the actual position;

[0052] It can be understood that the present machining fixture respectively supports the inner ring support portion and the outer ring support portion of the workpiece by respectively setting a first supporting assembly 2 and a second supporting assembly 3, and the clamping assembly is clamped and fixed to the first supporting assembly 2 to position and clamp the workpiece; by setting a positioning groove 21 in the first supporting assembly 2 and a positioning structure in the second supporting assembly 3, the circumferential distribution position of each positioning groove 21 and the circumferential distribution position of each positioning structure are matched with the distribution position of the inner cavity of the support plate, and the height position is also matched; the positioning groove 21 and the positioning structure perform two-point positioning of the positioning member 4 to ensure the angular position accuracy of the positioning member 4, and the second positioning section 42 of the positioning member 4 simulates the insertion of the machining tool into the inner cavity of the support plate. When each positioning member 4 can be smoothly inserted into the inner cavity of the support plate to the positioning groove 21, it can be judged that in actual machining, the machining tool will not process the inner wall of the inner cavity of the support plate, thereby avoiding scratches on the workpiece, ensuring that the problem of poor machining appearance quality is eliminated before part machining, improving the machining preparation and alignment efficiency, and shortening the workpiece machining time.

[0053] In this embodiment, the clamping assembly includes a pressing plate 5, a stud bolt 6 and a first nut 7. The pressing plate 5 is pressed onto the supporting portion of the inner ring of the workpiece. The stud bolt 6 is passed through the pressing plate 5 and is threadedly connected to the first supporting assembly 2. The first nut 7 is threadedly connected to the stud bolt 6 to lock the pressing plate 5. A step structure is provided at the end of the first supporting structure to radially position the workpiece and ensure concentricity. At the same time, the force of the clamping and clamping in contact with the workpiece is more uniform, thereby reducing deformation of the clamped workpiece. Furthermore, a groove that cooperates with the step structure is provided on the mating end face of the pressing plate 5, so that when the pressing plate 5 is pressed onto the workpiece, the step structure is embedded in the groove to enable the two to be radially positioned and matched. In order to make the pressing more stable, a second nut 9 is provided on the stud bolt 6 between the closed end faces of the pressing plate 5 and the first supporting member, and is tightened until it abuts against the first supporting member to ensure that the first nut 7 is more stable and reliable after being tightened.

[0054] In this embodiment, the diameter of the third positioning segment 43 is greater than the diameter of the second positioning segment 42, and the diameter of the first positioning segment 41 is smaller than the diameter of the second positioning segment 42, that is, the positioning member 4 is a step pin, and the positioning member 4 is inserted from the positioning structure of the outermost ring. The first positioning segment 41 passes through the positioning structure and the inner cavity of the support plate and cooperates with the positioning groove 21. At this time, the second positioning segment 42 is inserted into the inner cavity of the support plate, and the third positioning segment 43 is inserted into the positioning structure.

[0055] Furthermore, the processing fixture includes a first cylindrical pin 8 respectively passed through the pressure plate 5 and the first supporting assembly 2. Positioning holes are respectively provided on the pressure plate 5 and the first supporting assembly 2. The first cylindrical pin 8 is a step pin, and its lower diameter is smaller than the upper diameter. After the pressure plate 5 is pressed onto the workpiece, the first cylindrical pin 8 is inserted from top to bottom into the positioning hole of the pressure plate 5 to the positioning hole of the first supporting assembly 2, thereby realizing radial positioning of the pressure plate 5 and ensuring concentricity.

[0056] In this embodiment, the positioning structure includes a fixing hole opened in the second support group 3 and a bushing 31 arranged in the fixing hole, and the inner diameter of the bushing 31 matches the outer diameter of the third positioning section 43; during the clamping process, the positioning member 4 needs to be inserted into the positioning structure into the positioning groove 21. After long-term use, the inner wall of the positioning structure will be worn, affecting the positioning accuracy. Based on this, the positioning structure is set to be a fixing hole opened in the second support group 3 and a detachable bushing 31 arranged in the fixing hole. The bushing 31 ensures the positioning accuracy of the positioning member 4 at this position. After wear, only the bushing 31 needs to be replaced, which has lower maintenance costs and is easier to operate.

[0057] Similarly, a support block 32 is provided on the top of the second support group 3, which is connected to the second support member by a second screw 33. The support block 32 is used to cooperate with the support portion of the outer ring of the workpiece. The top of the support block 32 serves as a positioning reference. It will be worn during the long-term placement of the workpiece, and later maintenance only requires replacement of the support block 32.

[0058] In this embodiment, the fitting clearance between the first positioning section 41 and the positioning groove 21 is 0.002~0.012mm, and the fitting clearance between the third positioning section 43 and the positioning structure is 0.01~0.0275mm, so as to reduce the positioning error; the positioning member 4 has linearity and coaxiality, so the fitting clearance at the bushing 31 is larger than the fitting clearance of the positioning groove 21, so as to adjust the position and ensure that the positioning member 4 is accurately inserted.

[0059] In this embodiment, both ends of the positioning groove 21 are respectively provided with expansion structures whose size is larger than the width of the positioning groove 21 . After the expansion structures are provided at both ends of the positioning groove 21 , it is convenient to start processing the positioning groove 21 from the ends.

[0060] It can be understood that the bottom plate 1 and the surroundings of the fixture are hollowed out to reduce weight; holes matching the holes on the workpiece are provided on each mating surface of the fixture, and the hole diameter is increased by 1 mm compared to the hole position of the workpiece;

[0061] The method for processing the inner cavity mounting hole of the support plate of this embodiment is applied to the above-mentioned inner cavity mounting hole processing fixture of the support plate, and the processing method includes:

[0062] S1. Clamp the workpiece and align the fixture; specifically, press the workpiece into the fixture, press the pressure plate 5 and lock it; the jig support surface runout is ≤0.02, the jig positioning circle runout is ≤0.02, and the inspection hole F runout is ≤0.05;

[0063] S2. Process the angular holes of the workpiece installation edge; convert the angular holes of the blank into precision holes to determine the angle;

[0064] S3. Insert the positioning member 4 into the corresponding positioning groove 21 through the positioning structure;

[0065] S4. Rotate the workpiece in the first direction until the inner cavity of the support plate is close to the positioning member 4, and set the pressure gauge on one side of the support plate to zero. Rotate the workpiece in the second direction until the inner cavity of the support plate is close to the positioning member 4 and read the pressure gauge value. Rotate the workpiece in the first direction to half of the pressure gauge value. After this step, the second positioning section 42 of the positioning member 4 is located in the middle of the inner cavity of the support plate. Keep this clamping state to effectively avoid the tool from scratching the inner cavity of the support plate in subsequent processing;

[0066] S5. Clamp the workpiece and align the fixture; maintain the current circumferential position of the workpiece and lock the pressure plate 5; align the fixture support surface runout ≤0.02, and find the first reference D of the workpiece runout ≤0.02; align the angular hole A reference after the processing in step S2;

[0067] S6. Process the mounting holes in the inner cavity of the support plate.

[0068] Embodiment 1

[0069] This embodiment applies the fixture and processing method of the above preferred embodiment. The workpiece to be processed is a bearing seat bracket assembly, the inner ring of which is assembled with the power turbine bearing seat, the outer circle is assembled with the turbine casing, the inner and outer rings are connected by four support plates, the external air pipe penetrates from the support plate and is connected with the power seat, the four support plates are directly formed by casting, the diameter of the mounting hole in the support plate is φ12, and the gap with the inner wall of the inner cavity of the support plate is only 0.2-0.5mm, and the angular relationship between the angular hole of the blank and the support plate has a large deviation;

[0070] The fixture is designed with 4 φ6-wide positioning grooves 21 and φ14 bushings 31, and the axial position of the positioning grooves 21 and the bushings 31 relative to the fixture is consistent with the theoretical position of the distance from the center of the inner cavity of the workpiece support plate to the first reference D; the positioning grooves 21 and the first positioning section 41 have a clearance fit (single side 0.002-0.012mm), the bushings 31 and the third positioning section 43 have a clearance fit (single side 0.01-0.0275mm), and the bottom hole of the blank support plate is φ8;

[0071] The φ12 blank angular hole is aligned in step S1, and the angular hole is finely processed in step S2;

[0072] It should be noted that the workpiece has four support plate cavities. The bearing seat support assembly, the load-bearing casing assembly, the interstage guide assembly, the transition section assembly, etc. in the prior art all have four cavities, which are evenly distributed at 90° angular intervals. Figure 5 , step S3 comprises:

[0073] S31. Insert the positioning member 4 into the corresponding positioning groove 21 by the positioning structure in the X-reverse direction and the Y-direction direction. If the positioning member 4 can be inserted, proceed to step S4. If there is a positioning member 4 that cannot be inserted into the positioning groove 21, proceed to step S32.

[0074] S32. Adjust the position of the workpiece so that the positioning groove 21 that cannot be inserted is adjusted to the X positive direction, and insert the positioning member 4 into the corresponding positioning groove 21 again from the X reverse direction and the Y direction. If the positioning member 4 can be inserted, go to step S4. If there is a positioning member 4 that cannot be inserted, the angular deviation of the workpiece support plate is too large. Replace the workpiece and go to step S1.

[0075] It should be noted that the oil and gas pipe mounting holes of the workpiece have different apertures. In step S3, the positioning pin that cannot be inserted is adjusted to the positive direction of X, and the positioning member 4 is inserted into the inner cavity of the other support plate. When the positioning member 4 can be smoothly inserted into the inner cavity of the other three support plates, the inner cavity of the support plate in the positive direction of X is used as the processing position of the mounting hole with the smallest aperture, which can effectively avoid scratches on the workpiece and ensure that the workpiece is smoothly processed.

[0076] After the workpiece processing is completed through steps S3-S6, there is no scratch on the inner wall of the inner cavity of the workpiece support plate, the quality is stable, and the qualified rate is 100%.

[0077] Comparative Example 1

[0078] In this comparative example, reference Figure 6 and Figure 7 The difference from Example 1 is that the angular directions are determined by the four blank angular holes of the workpiece, and four φ8 angular pins are inserted into the angular holes, and then inserted into the 6mm wide vertical grooves fixed at 90° to each other in the center of the fixture. Since the tolerance of the φ8 blank hole is too large, the workpiece can still rotate greatly after the angular pins are inserted, and the distance between the φ8 blank hole and the groove on the fixture is too short to provide rotation constraints for the angular pins. In addition, the support plate is a special-shaped support plate, and the axial position of the hole cannot be determined by taking the φ8 blank hole as the angular direction. Therefore, the inner wall of the workpiece of the clamping scheme of Example 1 has scratches, and the depth is deep and there is no obvious pattern.

[0079] Comparative Example 2

[0080] In this comparative example, reference Figure 8 and Fig. 9 The difference from Example 1 is that four blank support plates are used to determine the angle together, and four external height-adjustable sliders at 90° to each other fix the axial height. Four φ12 angle pins are inserted into the support plates through the positioning holes of the sliders. This solution can ensure that the milling cutter and the angle pin are at the same height during subsequent processing, but the positioning hole of the external slider is too short, resulting in a jump of 0.8mm between the end and the front end of the angle pin, which cannot achieve the angular positioning effect. Therefore, the inner wall portion of the workpiece processed by the solution of Example 2 is processed, the depth is shallow, and the quality stability is poor.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fixture for machining mounting holes in the inner cavity of a support plate, which is used for machining workpieces with inner cavities of support plates in aircraft engines, and is characterized in that: include: A base plate (1) for structural support; A first support assembly (2) is arranged on the bottom plate (1) and is used to penetrate the workpiece and support the support portion of the inner ring of the workpiece. The first support assembly (2) is provided with a positioning groove (21) along the axial direction to match the circumferential distribution position and height position of each support plate; A clamping assembly, used for being pressed onto the support portion of the inner ring of the workpiece and connected to the first support member to clamp and fix the workpiece; A second support assembly (3) is arranged on the bottom plate (1) and is used to support the support portion of the outer ring of the workpiece. The second support assembly (3) is provided with a positioning structure that matches the circumferential distribution position and height position of each positioning groove (21); A positioning member (4) is radially penetrated in the positioning structure, and the positioning member (4) comprises, in sequence, along the axial direction, a first positioning section (41) matching the width of the positioning groove (21), a second positioning section (42) matching the size of a tool used for machining the mounting hole in the inner cavity of the support plate, and a third positioning section (43) matching the inner diameter of the positioning structure.

2. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: The clamping assembly includes a pressure plate (5), a stud bolt (6) and a first nut (7); the pressure plate (5) is pressed onto the supporting portion of the inner ring of the workpiece; the stud bolt (6) is passed through the pressure plate (5) and is threadedly connected to the first supporting assembly (2); the first nut (7) is threadedly connected to the stud bolt (6) to lock the pressure plate (5).

3. The fixture for machining the inner cavity mounting hole of the support plate according to claim 2, characterized in that: The processing fixture comprises a first cylindrical pin (8) respectively penetrating the pressing plate (5) and the first supporting assembly (2).

4. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: The positioning structure comprises a fixing hole opened in the second support assembly (3) and a bushing (31) arranged in the fixing hole, and the inner diameter of the bushing (31) matches the outer diameter of the third positioning section (43).

5. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: The matching clearance between the first positioning section (41) and the positioning groove (21) is 0.002-0.012 mm, and the matching clearance between the third positioning section (43) and the positioning structure is 0.01-0.0275 mm.

6. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: A support block (32) is provided at the top of the second support assembly (3), and the support block (32) is used to cooperate with the support portion of the outer ring of the workpiece.

7. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: Both ends of the positioning groove (21) are respectively provided with expansion structures whose size is larger than the width of the positioning groove (21).

8. The fixture for machining the inner cavity mounting hole of the support plate according to claim 1, characterized in that: The diameter of the third positioning section (43) is greater than the diameter of the second positioning section (42), and the diameter of the first positioning section (41) is smaller than the diameter of the second positioning section (42).

9. A method for processing a mounting hole in a support plate inner cavity, characterized in that: The fixture for machining the inner cavity mounting hole of the support plate according to any one of claims 1 to 8, wherein the machining method comprises: S1. Clamp the workpiece and align the fixture; S2. Processing the angle hole of the workpiece installation edge; S3. Insert the positioning member into the corresponding positioning groove through the positioning structure; S4. Rotate the workpiece in the first direction until the inner cavity of the support plate is close to the positioning piece, and set the pressure gauge on one side of the support plate to zero. Rotate the workpiece in the second direction until the inner cavity of the support plate is close to the positioning piece and then read the pressure gauge value. Rotate the workpiece in the first direction to half of the pressure gauge value. S5. Clamp the workpiece and align the fixture; S6. Process the mounting holes in the inner cavity of the support plate.

10. The method for machining the inner cavity mounting hole of the support plate according to claim 9, characterized in that: The workpiece has four support plate cavities, and step S3 includes: S31. Insert the positioning members into the corresponding positioning grooves by the positioning structures in the X-direction and Y-direction directions. If the positioning members can be inserted, proceed to step S4. If there are positioning members that cannot be inserted into the positioning grooves, proceed to step S32. S32. Adjust the position of the workpiece so that the positioning slot that cannot be inserted is adjusted to the positive X direction, and insert the positioning piece into the corresponding positioning slot again from the negative X direction and the Y direction. If the positioning piece can be inserted, go to step S4. If there is a positioning piece that cannot be inserted, the angular deviation of the workpiece support plate is too large. Replace the workpiece and go to step S1.

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