Clamp and method for machining outer circle face of thin-wall positioning bush for rotating shaft

Abstract

The invention relates to the technical field of aero-engine manufacturing, in particular to a clamp and method for machining the outer circle face of a thin-wall positioning bush for a rotating shaft. The clamp comprises a mandrel assembly, and the mandrel assembly comprises a left shaft body, a right shaft body and a connecting steel pipe connecting the left shaft body and the right shaft body. The left end of the left shaft body is sleeved with a clamping sleeve; a left compression nut, a left cone and a left clamp spring are sequentially mounted on the left shaft body from left to right; the left compression nut is in threaded fit with the left shaft body; the inner hole surface of the left cone is in sliding fit with the outer cylindrical surface of the left shaft body; the outer conical surface of the left cone is matched with the inner conical surface of the left clamp spring and is used for opening the left clamp spring; a right compression nut, a right cone and a right clamp spring are sequentially mounted on the right shaft body from right to left; the right compression nut is in threaded fit with the right shaft body; the inner hole surface of the right cone is in sliding fit with the outer cylindrical surface of the right shaft body; the outer conical surface of the right cone is matched with the inner conical surface of the right clamping spring and used for opening the right clamping spring. According to the clamp, the rigidity of the thin-wall positioning bushing in the machining process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengine manufacturing, and in particular to a fixture and a method for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft. Background Art

[0002] like Figure 1 The figure shows a schematic diagram of the structure of a small-sized thin-walled positioning bushing used to install the rotating shaft on the guide rail beam. Its outer diameter matches the guide rail beam installation base hole, and its inner hole matches the outer diameter of the rotating shaft to ensure the correct positioning of the rotating shaft. The main dimensions and shape and position parameters of this part are as follows:

[0003] L≈1001.95~1003mm;

[0004] d≈Φ28mm~Φ28.21mm, its roundness is 0.5, and its straightness is Φ0.2;

[0005] t≈0.895~1mm;

[0006] Aspect ratio L / d≈35.78~35.82.

[0007] The material grade of the small-sized, long, thin-walled positioning bushing is 0Cr17Ni7Al, the hardness is HRC≧40, the aspect ratio is 35.78-35.82, the wall thickness is 0.895-1, and the inner hole is processed by a deep hole drilling machine. During the outer shape processing, the rigidity is poor due to the structural requirements, and it is difficult to achieve the outer shape processing requirements by using a general clamping method. Summary of the invention

[0008] The main purpose of the present invention is to provide a fixture and method for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, aiming to solve the above-mentioned technical problems.

[0009] To achieve the above-mentioned purpose, on the one hand, the present invention proposes a fixture for processing the outer cylindrical surface of a thin-walled positioning sleeve for a rotating shaft, including a spindle assembly, the spindle assembly including a left shaft body, a right shaft body, and a connecting steel pipe connecting the left shaft body and the right shaft body; a clamping sleeve is provided on the left end of the left shaft body; a left clamping nut, a left vertebral body and a left retaining spring are installed on the left shaft body from left to right in sequence; the left clamping nut is threadedly matched with the left shaft body, and the inner hole surface of the left vertebral body is slidably matched with the outer cylindrical surface of the left shaft body; the outer conical surface of the left vertebral body is matched with the inner conical surface of the left retaining spring, which is used to open the left retaining spring; a right clamping nut, a right vertebral body and a right retaining spring are installed on the right shaft body from right to left in sequence; the right clamping nut is threadedly matched with the right shaft body, and the inner hole surface of the right vertebral body is slidably matched with the outer cylindrical surface of the right shaft body; the outer conical surface of the right vertebral body is matched with the inner conical surface of the right retaining spring, which is used to open the right retaining spring.

[0010] Preferably, a first cylindrical pin is inserted between the clamping sleeve and the left shaft body; a second cylindrical pin is inserted between the left retaining spring and the left shaft body; and a third cylindrical pin is inserted between the right retaining spring and the right shaft body.

[0011] Preferably, the left retaining spring and the left shaft body are interference fit; the right retaining spring and the right shaft body are interference fit; and a transition fit is adopted between the outer cylindrical surface of the left shaft body and the inner hole of the clamping sleeve.

[0012] Preferably, the right end of the left shaft body is inserted into the inner hole of the left end of the connecting steel pipe, and the two are interference fit; a fourth cylindrical pin is inserted between the connecting steel pipe and the left shaft body; the left end of the right shaft body is inserted into the inner hole of the right end of the connecting steel pipe, and the two are interference fit; a fifth cylindrical pin is inserted between the connecting steel pipe and the right shaft body.

[0013] Preferably, a first arc-shaped protrusion is provided on the left end surface of the left vertebral body, and a first groove is provided in the first arc-shaped protrusion; a first annular platform is integrally formed on the outer peripheral surface of the right end of the left clamping nut; the first annular platform is rotatably clamped in the first groove; a second arc-shaped protrusion is provided on the right end surface of the right vertebral body, and a second groove is provided in the second arc-shaped protrusion; a second annular platform is integrally formed on the outer peripheral surface of the left end of the right clamping nut; the second annular platform is rotatably clamped in the second groove.

[0014] Preferably, an open first plug interface is provided on the first arc-shaped protrusion; the first annular platform is inserted into the first card slot from the first plug interface; an open second plug interface is provided on the second arc-shaped protrusion; the second annular platform is inserted into the second card slot from the second plug interface.

[0015] Preferably, the single-side clearance between the outer cylindrical surface of the connecting steel pipe and the inner hole of the processed thin-walled positioning bushing is 0.015-0.035 mm.

[0016] Preferably, a first center hole is provided at the center of the left end face of the left shaft body; a second center hole is provided at the center of the right end face of the right shaft body; the fixture also includes a process bushing, which is respectively used to be mounted on the left retaining ring and the right retaining ring and to check the shape and position accuracy of the fixture; the outer cylindrical surface of the clamping sleeve is stepped, including a clamping section, and a retaining ring located at the right end of the clamping section.

[0017] Preferably, the full jump of the outer cylindrical surface of the clamping section of the clamping sleeve relative to the first center hole and the second center hole is 0.025; when the process bushing is mounted on the left retaining spring and the right retaining spring, and the left retaining spring and the right retaining spring are in a tightened state, the full jump of the outer peripheral surface of the process bushing relative to the first center hole and the second center hole is 0.025; the full jump of the outer peripheral surface of the connecting steel pipe relative to the first center hole and the second center hole is 0.025.

[0018] On the other hand, the present invention also provides a method for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, using the above-mentioned fixture, comprising the following steps:

[0019] S1. Fixture precision detection: After the two process bushings are respectively sleeved on the left retaining spring and the right retaining spring, turn the left clamping nut and push the left vertebra to move toward the center of the centripetal shaft assembly, and the outer conical surface of the left vertebra cooperates with the inner conical surface of the left retaining spring, so that the left retaining spring tightens the process bushing; turn the right clamping nut and push the right vertebra to move toward the center of the centripetal shaft assembly, and the outer conical surface of the right vertebra cooperates with the inner conical surface of the right retaining spring, so that the right retaining spring tightens the process bushing; detect the full runout of the outer circumference of the two process bushings relative to the first top hole and the second top hole; and detect the full runout of the outer circumference of the connecting steel pipe and the outer cylindrical surface of the clamping section of the clamping sleeve relative to the first top hole and the second top hole; if the fixture shape and position precision detection is qualified, remove its process bushing for storage;

[0020] S2. Installation, positioning and tightening of the thin-walled positioning bushing: Install the thin-walled positioning bushing on the connecting steel pipe, and apply force to the right vertebral body and the left vertebral body respectively by rotating the right clamping nut and the left clamping nut, so that the right vertebral body and the left vertebral body move toward the center of the spindle assembly. After the outer conical surfaces of the right vertebral body and the left vertebral body are respectively pressed against the inner conical surfaces of the right retaining spring and the left retaining spring, the right retaining spring and the left retaining spring expand radially to tighten the two ends of the thin-walled positioning bushing respectively;

[0021] S3. Processing of thin-walled positioning bushing: Clamp the clamping section of the clamping sleeve on the three-jaw chuck of the lathe, and tighten the center hole at the right end of the right shaft body with the center of the lathe tailstock; Align the outer circle of the clamping section of the clamping sleeve so that the runout value meets the design shape and position tolerance of the fixture, and then fine-turn the outer circle of the thin-walled positioning bushing;

[0022] S4. After finishing, the processed thin-walled positioning bushing is removed; and steps S2 and S3 are repeated to process another thin-walled positioning bushing to be processed.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] By using the fixture and method for machining the outer cylindrical surface of a thin-walled locating bushing for a rotating shaft provided by the present invention, the thin-walled locating bushing is installed on the connecting steel pipe during machining, and the right clamping nut and the left clamping nut are rotated to apply force to the right vertebral body and the left vertebral body respectively, so that the right vertebral body and the left vertebral body move toward the center of the centripetal shaft assembly. After the outer conical surfaces of the right vertebral body and the left vertebral body are respectively tightly attached to the inner conical surfaces of the right retaining spring and the left retaining spring, the right retaining spring and the left retaining spring radially expand to tighten the two ends of the thin-walled locating bushing respectively, thereby improving the rigidity of the thin-walled locating bushing during machining and ensuring the dimensional accuracy and form and position tolerance accuracy of the outer cylindrical surface of the thin-walled locating bushing after machining. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of a thin-walled positioning bushing;

[0027] Figure 2 The general diagram of the clamp provided by the present invention

[0028] Figure 3 A partial enlarged view of the left end of the clamp provided by the present invention;

[0029] Figure 4 A partial enlarged view of the right end of the clamp provided by the present invention;

[0030] Figure 5 It is a structural schematic diagram of the central axis assembly of the present invention;

[0031] Figure 6 It is a main cross-sectional view of the left retaining spring in the present invention;

[0032] Figure 7 for Figure 6 Left view of the middle left retaining spring;

[0033] Figure 8 The main cross-sectional view of the right retaining spring in the present invention

[0034] Fig. 9 for Figure 8 Right view of the middle right retaining spring;

[0035] Fig.10 It is a main cross-sectional view of the left vertebral body in the present invention;

[0036] Fig.11 for Fig.10 Left view of the middle left vertebra;

[0037] Fig.12 It is a main cross-sectional view of the left compression nut in the present invention;

[0038] Fig.13 for Fig.12 Left view of the center left compression nut;

[0039] Fig.14 It is a main cross-sectional view of the right vertebral body in the present invention;

[0040] Fig.15 for Fig.14 Right view of the middle right vertebra;

[0041] Fig.16 It is a main cross-sectional view of the right compression nut in the present invention;

[0042] Fig.17 for Fig.16 Right side view of the middle right compression nut;

[0043] Fig.18 It is a main cross-sectional view of the clamping sleeve in the present invention;

[0044] Fig.19 It is the main cross-sectional view of the process bushing in the present invention.

[0045] Explanation of the accompanying drawings: 1. Left shaft body; 1a. First center hole; 2. Connecting steel pipe; 3. Right shaft body; 3a. Second center hole; 4. Process bushing; 5. Right clamping nut; 5a. Second annular platform; 6. Right vertebral body; 6a. Second arc-shaped protrusion; 6b. Second slot; 6c. Second plug interface; 7. Right retaining spring; 8. Left retaining spring; 9. Left vertebral body; 9a. First arc-shaped protrusion; 9b. First slot; 9c. First plug interface; 10. Left clamping nut; 10a. First annular platform; 11. Clamping sleeve; 11a. Clamping section; 11b. Retaining ring; 12. First cylindrical pin; 13. Second cylindrical pin; 14. Third cylindrical pin; 15. Fourth cylindrical pin; 16. Fifth cylindrical pin. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] Combination Figures 2 to 19 As shown, on the one hand, this embodiment provides a fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, including a spindle assembly, the spindle assembly including a left shaft body 1, a right shaft body 3, and a connecting steel pipe 2 connecting the left shaft body 1 and the right shaft body 3; a clamping sleeve 11 is provided on the left end of the left shaft body 1; a left clamping nut 10, a left cone 9 and a left retaining spring 8 are installed on the left shaft body 1 from left to right in sequence; the left clamping nut 10 is threadedly matched with the left shaft body 1, and the inner hole surface of the left cone 9 is aligned with the outer cylindrical surface of the left shaft body 1 Sliding fit, the left vertebral body 9 can slide axially on the left shaft body 1; the outer conical surface of the left vertebral body 9 cooperates with the inner conical surface of the left retaining spring 8 to open the left retaining spring 8; the right clamping nut 5, the right vertebral body 6 and the right retaining spring 7 are installed on the right shaft body 3 from right to left in sequence; the right clamping nut 5 is threadedly matched with the right shaft body 3, the inner hole surface of the right vertebral body 6 is slidingly matched with the outer cylindrical surface of the right shaft body 3, and the right vertebral body 6 can slide axially on the right shaft body 3; the outer conical surface of the right vertebral body 6 cooperates with the inner conical surface of the right retaining spring 7 to open the right retaining spring 7.

[0050] Combination Figure 2 As shown, when the thin-walled positioning bushing to be processed is clamped, the thin-walled positioning bushing is installed on the connecting steel pipe 2, and the right clamping nut 5 is threadedly matched with the right shaft body 3. When the right clamping nut 5 is rotated to move to the left along the right shaft body 3, a leftward thrust can be formed on the right vertebral body 6, pushing the right vertebral body 6 to move to the left, so that the outer cone surface of the right vertebral body 6 is matched with the inner cone surface of the right retaining spring 7, which can be radially expanded in the inner hole at the right end of the thin-walled positioning bushing after the right retaining spring 7 is opened. Similarly, the left clamping nut 10 is threadedly matched with the left shaft body 1. When the left clamping nut 10 is rotated to move to the right along the left shaft body 1, a rightward thrust can be formed on the left vertebral body 9, pushing the left vertebral body 9 to move to the right, so that the outer cone surface of the left vertebral body 9 is matched with the inner cone surface of the left retaining spring 8, which can be radially expanded in the inner hole at the left end of the thin-walled positioning bushing after the left retaining spring 8 is opened. The clamping of the thin-walled positioning bushing is completed.

[0051] In this embodiment, when the entire fixture is installed on a lathe, the three-jaw chuck on the lathe is clamped on the clamping sleeve 11 to drive the entire fixture and the workpiece to be processed to rotate together.

[0052] Combination Figure 2 As shown, a first cylindrical pin 12 is inserted between the clamping sleeve 11 and the left shaft body 1; a second cylindrical pin 13 is inserted between the left retaining spring 8 and the left shaft body 1; and a third cylindrical pin 14 is inserted between the right retaining spring 7 and the right shaft body 3. Further, the left retaining spring 8 and the left shaft body 1 are interference fit; the right retaining spring 7 and the right shaft body 3 are interference fit; and a transition fit is adopted between the outer cylindrical surface of the left shaft body 1 and the inner hole of the clamping sleeve 11. The right end of the left shaft body 1 is inserted into the inner hole of the left end of the connecting steel pipe 2, and the two are interference fit; a fourth cylindrical pin 15 is inserted between the connecting steel pipe 2 and the left shaft body 1; the left end of the right shaft body 3 is inserted into the inner hole of the right end of the connecting steel pipe 2, and the two are interference fit; and a fifth cylindrical pin 16 is inserted between the connecting steel pipe 2 and the right shaft body 3.

[0053] Combination Figure 2 , Figures 10 to 17 As shown, a first arc-shaped protrusion 9a is provided on the left end surface of the left vertebral body 9, and a first clamping groove 9b is provided in the first arc-shaped protrusion 9a; a first annular platform 10a is integrally formed on the right end outer peripheral surface of the left clamping nut 10; the first annular platform 10a is rotatably clamped in the first clamping groove 9b; a second arc-shaped protrusion 6a is provided on the right end surface of the right vertebral body 6, and a second clamping groove 6b is provided in the second arc-shaped protrusion 6a; a second annular platform 5a is integrally formed on the left end outer peripheral surface of the right clamping nut 5; the second annular platform 5a is rotatably clamped in the second clamping groove 6b. Further, an open first plug-in interface 9c is provided on the first arc-shaped protrusion 9a; an open second plug-in interface 6c is provided on the second arc-shaped protrusion 6a.

[0054] By adopting the above structure, the first clamping groove 9b on the left cone 9 is used to rotate and clamp with the first annular platform 10a on the left clamping nut 10. When the left clamping nut 10 is rotated on the left shaft body 1 and moves along the axial direction of the left shaft body 1, the left cone 9 can be driven to move along the axial direction of the left shaft body 1 on the left shaft body 1. Similarly, the second clamping groove 6b on the right cone 6 is used to rotate and clamp with the second annular platform 5a on the right clamping nut 5. When the right clamping nut 5 is rotated on the right shaft body 3 and moves along the axial direction of the right shaft body 3, the right cone 6 can be driven to move along the axial direction of the right shaft body 3 on the right shaft body 3. By providing the first plug-in interface 9c, it is convenient to insert the first annular platform 10a of the left clamping nut 10 from the first plug-in interface 9c into the first clamping groove 9b; similarly, by providing the second plug-in interface 6c, it is convenient to insert the second annular platform 5a of the right clamping nut 5 from the second plug-in interface 6c into the second clamping groove 6b.

[0055] In this embodiment, the single-side clearance between the outer cylindrical surface of the connecting steel pipe 2 and the inner hole of the processed thin-walled positioning bushing is 0.015-0.035 mm, so that the outer cylindrical surface of the connecting steel pipe 2 and the inner hole surface of the processed thin-walled positioning bushing form a clearance fit, which is convenient for installing the processed thin-walled positioning bushing.

[0056] Combination Figures 2 to 4 As shown, a first top hole 1a is provided at the center of the left end face of the left shaft body 1; a second top hole 3a is provided at the center of the right end face of the right shaft body 3; the fixture also includes a process bushing 4, which is used to be respectively sleeved on the left retaining spring 8 and the right retaining spring 7 and to check the shape and position accuracy of the fixture; the outer cylindrical surface of the clamping sleeve 11 is stepped, including a clamping section 11a, and a retaining ring 11b located at the right end of the clamping section 11a. The full jump of the outer cylindrical surface of the clamping section 11a of the clamping sleeve 11 relative to the first center hole 1a and the second center hole 3a is 0.025; when the process bushing 4 is mounted on the left retaining spring 8 and the right retaining spring 7, and the left retaining spring 8 and the right retaining spring 7 are in a tightened state, the full jump of the outer peripheral surface of the process bushing 4 relative to the first center hole 1a and the second center hole 3a is 0.025; the full jump of the outer peripheral surface of the connecting steel pipe 2 relative to the first center hole 1a and the second center hole 3a is 0.025.

[0057] On the other hand, this embodiment also provides a method for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, using the above-mentioned fixture, comprising the following steps:

[0058] S1. Fixture precision detection: After the two process bushings 4 are respectively sleeved on the left retaining spring 8 and the right retaining spring 7, the left clamping nut 10 is rotated and the left vertebral body 9 is pushed to move toward the center of the spindle assembly. The outer conical surface of the left vertebral body 9 cooperates with the inner conical surface of the left retaining spring 8, so that the left retaining spring 8 tightens the process bushing 4; the right clamping nut 5 is rotated and the right vertebral body 6 is pushed to move toward the center of the spindle assembly. The outer conical surface of the right vertebral body 6 cooperates with the inner conical surface of the right retaining spring 7, so that the right retaining spring 7 tightens the process bushing 4; the full runout of the outer circumferential surfaces of the two process bushings 4 relative to the first top hole 1a and the second top hole 3a is detected; and the full runout of the outer circumferential surface of the connecting steel pipe 2 and the outer cylindrical surface of the clamping section 11a of the clamping sleeve 11 relative to the first top hole 1a and the second top hole 3a is detected; if the fixture shape and position precision detection is qualified, its process bushing 4 is removed and stored;

[0059] S2. Installation, positioning and tightening of the thin-walled positioning bushing: Install the thin-walled positioning bushing on the connecting steel pipe 2, and apply force to the right vertebral body 6 and the left vertebral body 9 by rotating the right clamping nut 5 and the left clamping nut 10 respectively, so that the right vertebral body 6 and the left vertebral body 9 move toward the center of the spindle assembly. After the outer conical surfaces of the right vertebral body 6 and the left vertebral body 9 are respectively pressed against the inner conical surfaces of the right retaining spring 7 and the left retaining spring 8, the right retaining spring 7 and the left retaining spring 8 are radially expanded to tighten the two ends of the thin-walled positioning bushing respectively;

[0060] S3, processing of thin-walled positioning bushing: clamp the clamping section 11a of the clamping sleeve 11 on the three-jaw chuck of the lathe, and the top hole at the right end of the right shaft body 3 is tightly matched with the top of the lathe tailstock; align the outer circle of the clamping section 11a of the clamping sleeve 11 so that the runout value meets the design shape and position tolerance of the fixture, and then fine-turn the outer circle of the thin-walled positioning bushing;

[0061] S4. After finishing, the processed thin-walled positioning bushing is removed; and steps S2 and S3 are repeated to process another thin-walled positioning bushing to be processed.

[0062] In step S1, when the accuracy of the fixture is tested, the outer cylindrical surface of the clamping section 11a of the clamping sleeve 11 is required to have a full runout of 0.025 relative to the first top hole 1a and the second top hole 3a; after the process bushing 4 is sleeved on the left clamping spring 8 and the right clamping spring 7, and the left clamping spring 8 and the right clamping spring 7 are in a tightened state, the outer peripheral surface of the process bushing 4 has a full runout of 0.025 relative to the first top hole 1a and the second top hole 3a; the outer peripheral surface of the connecting steel pipe 2 has a full runout of 0.025 relative to the first top hole 1a and the second top hole 3a. If this requirement is met, the fixture needs to be repaired to meet this requirement.

[0063] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, comprising a spindle assembly, characterized in that: The spindle assembly comprises a left spindle body (1), a right spindle body (3), and a connecting steel pipe (2) connecting the left spindle body (1) and the right spindle body (3); a clamping sleeve (11) is sleeved on the left end of the left spindle body (1); A left clamping nut (10), a left cone (9) and a left retaining spring (8) are sequentially installed on the left shaft body (1) from left to right; the left clamping nut (10) is threadedly engaged with the left shaft body (1), and the inner hole surface of the left cone (9) is slidably engaged with the outer cylindrical surface of the left shaft body (1); the outer conical surface of the left cone (9) is engaged with the inner conical surface of the left retaining spring (8) to open the left retaining spring (8); A right clamping nut (5), a right cone (6) and a right retaining spring (7) are sequentially installed on the right shaft body (3) from right to left; the right clamping nut (5) is threadedly engaged with the right shaft body (3), and the inner hole surface of the right cone (6) is slidingly engaged with the outer cylindrical surface of the right shaft body (3); the outer conical surface of the right cone (6) is engaged with the inner conical surface of the right retaining spring (7) to open the right retaining spring (7).

2. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: A first cylindrical pin (12) is inserted between the clamping sleeve (11) and the left shaft body (1); A second cylindrical pin (13) is inserted between the left clamping spring (8) and the left shaft body (1); A third cylindrical pin (14) is inserted between the right clamping spring (7) and the right shaft body (3).

3. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: The left retaining spring (8) and the left shaft body (1) are in interference fit; the right retaining spring (7) and the right shaft body (3) are in interference fit; and a transition fit is adopted between the outer cylindrical surface of the left shaft body (1) and the inner hole of the clamping sleeve (11).

4. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: The right end of the left shaft body (1) is inserted into the inner hole of the left end of the connecting steel pipe (2), and the two are interference fit; a fourth cylindrical pin (15) is inserted between the connecting steel pipe (2) and the left shaft body (1); The left end of the right shaft body (3) is inserted into the inner hole of the right end of the connecting steel pipe (2), and the two are interference fit; a fifth cylindrical pin (16) is inserted between the connecting steel pipe (2) and the right shaft body (3).

5. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: A first arc-shaped protrusion (9a) is provided on the left end surface of the left cone (9), and a first clamping groove (9b) is provided in the first arc-shaped protrusion (9a); a first annular platform (10a) is integrally formed on the outer peripheral surface of the right end of the left clamping nut (10); the first annular platform (10a) is rotatably clamped in the first clamping groove (9b); a second arc-shaped protrusion (6a) is provided on the right end surface of the right cone (6), and a second clamping groove (6b) is provided in the second arc-shaped protrusion (6a); a second annular platform (5a) is integrally formed on the outer peripheral surface of the left end of the right clamping nut (5); the second annular platform (5a) is rotatably clamped in the second clamping groove (6b).

6. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 5, characterized in that: An open first plug-in interface (9c) is provided on the first arc-shaped protrusion (9a); the first annular platform (10a) is inserted into the first card slot (9b) from the first plug-in interface (9c); An open second plug-in interface (6c) is provided on the two arc-shaped protrusions (6a); the second annular platform (5a) is inserted into the second card slot (6b) from the second plug-in interface (6c).

7. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: The single-side clearance between the outer cylindrical surface of the connecting steel pipe (2) and the inner hole of the processed thin-walled positioning bushing is 0.015-0.035 mm.

8. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 1, characterized in that: A first center hole (1a) is arranged at the center of the left end face of the left shaft body (1); a second center hole (3a) is arranged at the center of the right end face of the right shaft body (3); the fixture further comprises a process bushing (4) which is respectively used to be sleeved on the left retaining ring (8) and the right retaining ring (7) and to check the shape and position accuracy of the fixture; the outer cylindrical surface of the clamping sleeve (11) is stepped, comprising a clamping section (11a) and a retaining ring (11b) located at the right end of the clamping section (11a).

9. A fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft as claimed in claim 8, characterized in that: The outer cylindrical surface of the clamping section (11a) of the clamping sleeve (11) has a full runout of 0.025 relative to the first center hole (1a) and the second center hole (3a); When the process bushing (4) is sleeved on the left retaining spring (8) and the right retaining spring (7), and the left retaining spring (8) and the right retaining spring (7) are in a tightened state, the full jump of the outer peripheral surface of the process bushing (4) relative to the first center hole (1a) and the second center hole (3a) is 0.025; The total runout of the outer peripheral surface of the connecting steel pipe (2) relative to the first center hole (1a) and the second center hole (3a) is 0.

025.

10. A method for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft, characterized in that: The fixture for machining the outer cylindrical surface of a thin-walled positioning bushing for a rotating shaft according to claim 9 comprises the following steps: S1. Fixture precision test: After the two process bushings (4) are respectively mounted on the left retaining spring (8) and the right retaining spring (7), the left clamping nut (10) is rotated to push the left vertebral body (9) toward the center of the spindle assembly. The outer conical surface of the left vertebral body (9) cooperates with the inner conical surface of the left retaining spring (8), so that the left retaining spring (8) supports the process bushing (4); the right clamping nut (5) is rotated to push the right vertebral body (6) toward the center of the spindle assembly. The outer conical surface of the right vertebral body (6) cooperates with the inner conical surface of the right retaining spring (8). 7) so that the right retaining ring (7) tightens the process bushing (4); detects the full jump of the outer circumference of the two process bushings (4) relative to the first top hole (1a) and the second top hole (3a); and detects the full jump of the outer circumference of the connecting steel pipe (2) and the outer cylindrical surface of the clamping section (11a) of the clamping sleeve (11) relative to the first top hole (1a) and the second top hole (3a); if the fixture shape and position accuracy test is qualified, remove its process bushing (4) for storage; S2. Installation, positioning and tightening of the thin-walled positioning bushing: The thin-walled positioning bushing is installed on the connecting steel pipe (2), and the right compression nut (5) and the left compression nut (10) are rotated to apply force to the right vertebral body (6) and the left vertebral body (9) respectively, so that the right vertebral body (6) and the left vertebral body (9) move toward the center of the spindle assembly. After the outer conical surfaces of the right vertebral body (6) and the left vertebral body (9) are respectively pressed against the inner conical surfaces of the right retaining spring (7) and the left retaining spring (8), the right retaining spring (7) and the left retaining spring (8) are radially expanded to tighten the two ends of the thin-walled positioning bushing respectively; S3, processing of thin-walled positioning bushing: clamping the clamping section (11a) of the clamping sleeve (11) on the three-jaw chuck of the lathe, and the center hole at the right end of the right shaft body (3) is tightly matched with the center of the lathe tailstock; aligning the outer circle of the clamping section (11a) of the clamping sleeve (11) so that the runout value meets the design shape and position tolerance of the fixture, and then finishing the outer circle of the thin-walled positioning bushing; S4. After finishing, the processed thin-walled positioning bushing is removed; and steps S2 and S3 are repeated to process another thin-walled positioning bushing to be processed.

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