A method for repairing an oversized hole
By performing sealing verification and annular groove design before precision machining of the bushing inner hole, combined with adhesive curing process, the problem of scrapping caused by unqualified bushing sealing was solved, achieving efficient hole repair and improved sealing reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA HANGFA SOUTH IND CO LTD
- Filing Date
- 2025-11-12
- Publication Date
- 2026-07-21
AI Technical Summary
In the existing technology, the failure to seal properly after the inner hole of the bushing is finished results in scrapping, which leads to waste of materials and time, reduced production efficiency and increased costs.
Before the bushing inner hole is precision machined, a sealing verification is performed. Multiple sealing rings are formed through precision boring, ring groove design, and adhesive curing process to ensure that the sealing test is passed before the final dimension machining, thus avoiding rework.
It significantly improves the success rate of repairs and processing efficiency, enhances sealing reliability and bonding strength, and avoids waste of finishing work caused by substandard sealing.
Smart Images
Figure CN121179138B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aero-engine manufacturing technology, and more specifically, to a method for repairing out-of-tolerance holes. Background Technology
[0002] In the manufacturing process of aluminum-magnesium alloy casings for aero engines, critical components such as mounting and positioning holes and precision oil passage holes often suffer from problems such as out-of-tolerance hole diameters, positional deviations, and non-compliance with cylindricity standards due to defects in the blanks or machining errors. Currently, interference-fitting bushings are commonly used to repair these precision holes.
[0003] The existing bushing repair process involves first machining a bushing with specific inner and outer diameters based on the enlarged dimensions of the out-of-tolerance hole. Then, the bushing is press-fitted into the hole using an interference fit. Finally, a sealing test is performed on the repaired hole. However, because this process places the sealing verification after the bushing is pressed in and the inner hole is finished, if the sealing test fails—that is, if there is a microscopic gap between the bushing and the base hole wall causing leakage—the bushing's inner hole has already been machined to its final size, making effective repair impossible. The part must be scrapped, resulting in significant waste of materials and time, reduced production efficiency, and increased production costs. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art, which only discovers the sealing failure after the inner hole of the bushing is precision machined, leading to scrap. It provides a method for repairing out-of-tolerance holes, which verifies the sealing performance in advance before the inner hole of the bushing is precision machined, and discovers the risk of leakage before the final size processing. This avoids rework or even scrap due to sealing failure after precision machining, and improves the repair success rate and processing efficiency.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for repairing out-of-tolerance holes is provided, including the following steps: S1. Measure the parameters of the out-of-tolerance hole and select the bushing material according to the casing material; S2. Perform fine boring and reaming on the out-of-tolerance hole. After the fine boring and reaming is completed, measure the actual final hole diameter and the actual final hole depth of the out-of-tolerance hole. S3. Select the blank bar material according to the bushing material, and perform rough turning and finish turning of the outer diameter of the blank bar material in sequence according to the actual value of the final hole diameter. S4. A ring groove is machined on the outer circle of the precision-machined blank bar. S5. Cut the blank bar into a solid part according to the actual value of the final hole depth, and deburr the end of the solid part. S6. Press the solid part that has been processed as described above into the tolerance hole of the part and then perform adhesive bonding and curing. S7. Perform a sealing test on the out-of-tolerance hole; S8. After the sealing test is passed, the solid part is subjected to rough drilling, semi-fine boring and fine boring in sequence, so as to process an inner hole in the solid part that meets the design size of the out-of-tolerance hole, and form the bushing.
[0006] This repair method involves precisely measuring the parameters of the out-of-tolerance hole and designing and machining a solid part with annular grooves. By setting annular grooves on the outer circumference of the bushing, a storage space for the sealing medium is provided, forming a strong and reliable multi-layered sealing ring between the bushing and the part. This significantly improves the sealing reliability and bonding strength, preventing the bushing from rotating within the out-of-tolerance hole during finishing. This ensures that the inner hole can be finished after assembly. The cylindrical solid part is then press-fitted into the out-of-tolerance hole, and a reliable sealing structure is formed using an adhesive curing process. Ultimately, the sealing test can be performed before the final finishing of the bushing's inner hole, effectively enabling early identification and avoidance of leakage risks. This method not only significantly improves the sealing reliability and bonding strength of the repaired area through the annular groove structure and adhesive process, but also avoids the waste of subsequent finishing work caused by unqualified sealing through optimized process sequence, significantly improving the repair success rate and processing efficiency.
[0007] Furthermore, in step S2, when the depth of the out-of-tolerance hole is less than 3mm, the final hole depth is increased to be greater than or equal to 3mm by precision boring. This step, by actively deepening the original shallow hole, ensures that the bushing has the necessary installation space and structural integrity, enabling the annular groove structure to be effectively formed and perform its adhesive storage and sealing function. It also enhances the load-bearing capacity of the bushing within the out-of-tolerance hole, thereby significantly expanding the adaptability of this repair process to out-of-tolerance holes of different depths.
[0008] Further, in step S3, the outer diameter is precision machined to the outer diameter dimension D, wherein the outer diameter dimension D satisfies:
[0009] in, This represents the final actual aperture value. For the interference and This dimensional design is achieved by adjusting the bushing outer diameter D with the final bore diameter measurement. The quantitative relationship between X and the precision interference Z ensures the precise control of the interference fit, provides sufficient bonding strength to prevent bushing loosening, and controls the assembly stress within a reasonable range to avoid deformation of the thin-walled casing.
[0010] Further, in step S4, at least one annular groove is machined on the outer diameter of the blank bar, wherein the axial width dimension of the annular groove is... satisfy:
[0011] in, The length dimension of the bushing is equal to the actual value of the final hole depth.
[0012] When the bushing length L is less than 3mm, this bushing structure cannot be used for combined repair. If it is necessary, the depth of the out-of-tolerance hole in the part should be increased to 3mm as needed, that is, the bushing length L should be equal to 3mm. This invention provides a shaped storage space for the sealing medium by setting a ring groove of a specific size on the outer cylindrical surface of the solid part. When it is interference-fitted with the hole of the part, the sealing medium in the ring groove is squeezed and filled with all the micro gaps. After curing, it forms multiple continuous sealing rings, thereby achieving reliable sealing. This not only solves the leakage problem of high-pressure oil and gas media, but also enhances the bonding strength of the bushing, fundamentally improving the sealing performance and structural reliability after bushing repair.
[0013] Furthermore, in step S4, when the length L of the bushing is less than 5mm, only one annular groove is provided on the outer circumference of the blank bar. When the bushing length L is less than 5mm, by optimizing the annular groove structure to only provide one groove, the sealing performance and structural integrity are balanced within the limited axial space: it ensures that an effective sealing ring can be formed to meet the most basic sealing function, while maximizing the preservation of the bushing's solid material, preventing excessive weakening of its overall rigidity and strength due to too many annular grooves, thereby ensuring the reliability of the bushing during press-fitting and use.
[0014] Further, in step S4, the axial position dimension L1 of the annular groove satisfies: The radial depth h of the annular groove is 0.04mm to 0.05mm. By precisely setting the axial position of the annular groove at L1=LC / 2 and controlling its radial depth h within a microscale of 0.04mm to 0.05mm, this structure ensures sufficient volume to accommodate the sealing medium while minimizing the weakening of the bushing body's strength. This ensures that during interference fitting, the sealant can be uniformly squeezed and fully filled to the mating interfaces on both sides of the annular groove, forming a continuous and dense sealing ring. Ultimately, a balance is achieved between achieving reliable high-pressure sealing and maintaining the structural load-bearing strength.
[0015] Furthermore, in step S5, the end face of the solid part is rounded, and the radius C of the rounded circle is less than or equal to 0.2 mm. By rounding the end face of the solid part, burrs are effectively removed during processing, and the sealant layer is prevented from being scratched during assembly, allowing the sealing medium to flow smoothly and fill evenly during the pressing process.
[0016] Further, step S6 includes the following steps: S61. Check whether there are burrs on the surface of the out-of-tolerance hole and the surface of the solid part. After removing dust, perform degreasing treatment and place the degreased parts and solid parts at room temperature to dry. S62. Heating the part to enlarge the out-of-tolerance hole or cooling the solid part to reduce the outer diameter of the solid part; S63. A sealing medium is uniformly coated on the surface of the out-of-tolerance hole and the outer circumferential surface of the solid part. S64. Press the solid part into the tolerance hole, rotate the solid part to keep the sealing medium evenly distributed, and remove the overflowed sealing medium. S65. The part is cured at room temperature, then baked and cured in an electric furnace and cooled with the furnace. After cooling, visual inspection shows that there is no residual sealing medium at the out-of-tolerance holes. This adhesive curing process, through surface treatment, hot and cold assembly control, precise adhesive layer coating and rotary uniform application, and a staged curing process, ensures that the sealing medium can fully fill the annular groove and be evenly distributed throughout the mating interface, thereby forming a dense adhesive layer without gaps or defects between the solid part and the substrate, ultimately optimizing the strength and sealing performance of the connection structure.
[0017] Further, in step S62, heating the part includes placing it in an electric furnace and heating it to 95~105℃ for baking; the cooling process includes placing the solid part in a pure nitrogen freezer for cooling. By heating the part to 95~105℃ to achieve thermal expansion of the hole wall, and simultaneously using pure nitrogen to cool the solid part to cause its outer diameter to shrink, this temperature difference synergistic effect creates an assembly gap. This not only makes the interference fit process smooth and avoids surface scratches, but also ensures that the sealing medium is not excessively sheared during assembly, providing a key guarantee for forming a complete and uniform sealing interface.
[0018] Furthermore, in step S63, the sealing medium is an anaerobic adhesive. Choosing an anaerobic adhesive as the sealing medium allows it to rapidly cure in the sealed environment of the annular groove, which is in contact with the metal surface and isolated from air, forming a tough solid polymer. This not only fills the microscopic gaps between the solid component and the substrate to achieve a reliable seal, but also significantly enhances the structural connection strength through synergistic effects with interference fits. Simultaneously, its excellent oil resistance, temperature resistance, and media resistance ensure the long-term sealing stability of the repaired area under the complex operating conditions of an aero-engine.
[0019] Further, in step S65, the room temperature curing time is greater than or equal to 120 minutes, and the baking curing temperature is 95~105℃ for 45~55 minutes. This curing process ensures sufficient leveling and preliminary shaping of the colloid by setting a room temperature initial curing time of ≥120 minutes, followed by cross-linking curing through a medium-temperature baking at 95~105℃ for 45~55 minutes. This staged temperature control strategy ensures that the sealing medium can fully penetrate and fill the micro-gap to form a high-strength adhesive layer, while effectively releasing the internal stress of the adhesive layer through a slow heating and cooling process. Ultimately, this results in a sealing structure that simultaneously possesses excellent interfacial bonding strength, heat resistance stability, and resistance to media penetration.
[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The process route of pressing the bushing into place, bonding and curing, sealing test and final finishing is adopted. This allows the sealing to be verified in advance before the inner hole of the bushing is finished. The risk of leakage can be detected before the final size is processed, avoiding rework or even scrap due to unqualified sealing after finishing, thus improving the repair success rate and processing efficiency. 2. Filling the out-of-tolerance holes with solid bushings is equivalent to "welding" the complete blank at the defect, providing a variety of options for subsequent precision machining methods, while avoiding the inherent thermal deformation, shrinkage and internal stress problems of the welding process. 3. By setting an annular groove on the outer circle of the bushing, a storage space is provided for the sealing medium, forming a strong and reliable multi-layer sealing ring between the bushing and the parts, which significantly improves the sealing reliability and bonding strength of the bushing part. Attached Figure Description
[0021] Figure 1 A flowchart of the bushing machining process; Figure 2 This is a schematic diagram of step S61; Figure 3 This is a schematic diagram of step S63; Figure 4 This is a schematic diagram of step S8; Figure 5 This is a structural schematic diagram of the solid component.
[0022] In the attached diagram: 100, bushing; 110, annular groove; 200, part; 210, tolerance hole; 300, sealing medium; 400, solid part. Detailed Implementation
[0023] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0024] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0025] Example 1 This embodiment is the first embodiment of the out-of-tolerance hole repair method, such as... Figure 1 As shown, it includes the following steps: S1. Measure the parameters of the out-of-tolerance hole 210, and select the material of bushing 100 according to the casing material; S2. Perform precision boring and reaming on the out-of-tolerance hole 210. After the precision boring and reaming is completed, measure the actual final hole diameter and the actual final hole depth of the out-of-tolerance hole 210. S3. Select a blank bar material according to the material of bushing 100, and perform rough turning and finish turning of the outer diameter of the blank bar material in sequence according to the actual value of the final hole diameter. S4. A ring groove 110 is machined on the outer circle of the precision-machined blank bar. S5. Cut the blank bar into solid parts 400 according to the actual value of the final hole depth, and deburr the ends of the solid parts 400. S6. Press the solid part 400, which has been processed as described above, into the tolerance hole 210 of the part 200 and then perform adhesive bonding and curing. S7. Perform a sealing test on the out-of-tolerance hole 210; S8. After the sealing test is passed, the solid part 400 is subjected to rough drilling, semi-fine boring and fine boring in sequence, so as to process an inner hole in the solid part 400 that meets the design size of the out-of-tolerance hole 210, and form the bushing 100.
[0026] In step S3, the outer circle is precision machined to the outer diameter dimension D, and the outer diameter dimension D satisfies:
[0027] in, This represents the final actual aperture value. For the interference and .
[0028] In step S4, at least one annular groove 110 is machined on the outer diameter of the blank bar, wherein the axial width dimension of the annular groove 110 is... satisfy:
[0029] in, The length dimension of the bushing 100 is equal to the actual value of the final hole depth.
[0030] In step S4, the axial position dimension L1 of the annular groove 110 satisfies: L1 = L - C 2. The radial depth h of the annular groove 110 is 0.04mm~0.05mm.
[0031] In step S5, the end face of the solid part 400 is provided with a rounded edge, and the radius C of the rounded edge is less than or equal to 0.2 mm.
[0032] This embodiment selects the oil inlet hole of a typical complex thin-walled multi-oil-path aluminum-magnesium casing for repair. First, the parameters of the out-of-tolerance hole 210 are measured, and the diameter of the precision oil inlet hole is determined. 15 (+0.032, 0) out of tolerance The following defects were found: 15.07 mm deviation, positional tolerance (0.03, A, B) exceeding the tolerance by 0.072, cylindricity (0.02, 0.034) exceeding the tolerance. The precision oil inlet hole depth is 18 mm, affecting component assembly and rendering the casing unusable. The casing material is ZL114A, and the bushing 100 material is also ZL114A.
[0033] The out-of-tolerance hole 210 is enlarged by precision boring to correct its position and cylindricity. After precision boring and enlargement, the actual final diameter of the out-of-tolerance hole 210 is measured. The actual final hole depth is 18mm, and the diameter is 15.162mm. The outer diameter D is calculated based on the actual final hole depth: D = 15.162 + 2 × 0.02 = 15.202mm. In this embodiment, the interference fit Z is chosen to be 0.02mm. The selected specification in this embodiment is... A 25×30mm aluminum rod is used as the blank material. The outer diameter of the blank material is rough turned and then finish turned to process it to the outer diameter dimension D.
[0034] Subsequently, an annular groove 110 is machined on the outer diameter of the precision-machined bar stock. In this embodiment, the depth of the precision oil inlet hole is 18mm, therefore the length L of the bushing 100 is 18mm, and the axial width of the annular groove 110 is... =2mm, the remaining dimensions of the annular groove 110 are selected as follows: axial position dimension L1 of the annular groove 110 = / 2=1mm, the radial depth h of the annular groove 110 is 0.05mm, and the rounding radius C is 0.1mm. The finished solid part is 400... Figure 5 As shown, the actual dimension of solid part 400 is D=15.204mm. =2.01mm, L1=1.06mm, h=0.05mm, C=0.13mm.
[0035] The blank bar is cut to form a solid part 400 according to the actual value of the final hole depth of 18mm, and the end of the solid part 400 is deburred. Then, the solid cylindrical part 400 is assembled into the out-of-tolerance hole 210 and glued and cured. After curing, a sealing test is performed.
[0036] In this embodiment, the sealing test is conducted by introducing pressure from the oil outlet of the oil circuit under the conditions of rust inhibitor pressure of 0.5±0.05MPa and temperature of 25±6℃, and maintaining the pressure for 5 minutes. Special attention is paid to checking the out-of-tolerance hole 210, and no leakage is allowed.
[0037] After passing the sealing test, the inner hole is machined to the design dimensions of the precision oil inlet in the solid part (400mm). After repair, the dimensions of the oil inlet in the casing are measured using a coordinate measuring machine (CMM) to determine the hole diameter. The measurement result of 15 (+0.032,0) is The measurement results for 15.026mm, positional tolerance |0.03|A|B| are 0.03, and cylindricity |0.02| are 0.015. The casing meets the design requirements, and the out-of-tolerance hole 210 has been successfully repaired.
[0038] Example 2 This embodiment is the second embodiment of the method for repairing out-of-tolerance hole 210, which includes the following steps: In step S2, when the depth of the out-of-tolerance hole 210 is less than 3mm, the final hole depth is made greater than or equal to 3mm by precision boring and enlarging.
[0039] In step S4, when the length L of the bushing 100 is less than 5mm, the annular groove 110 is provided only once on the outer circle of the blank bar.
[0040] Step S6 includes the following steps: S61. Check whether there are burrs on the surface of the out-of-tolerance hole 210 and the surface of the solid part 400. After removing dust, perform degreasing treatment and place the degreased parts 200 and 400 at room temperature to dry. S62. Heating the part 200 to enlarge the out-of-tolerance hole 210 or cooling the solid part 400 to reduce the outer diameter of the solid part 400; S63. A sealing medium 300 is uniformly coated on the surface of the out-of-tolerance hole 210 and the outer circumferential surface of the solid part 400. S64. Press the solid part 400 into the tolerance hole 210, rotate the solid part 400 to keep the sealing medium 300 evenly distributed, and remove the overflowing sealing medium 300. S65. Place the part 200 at room temperature to cure, then bake and cure in an electric furnace and cool with the furnace. After cooling, visually inspect that there is no residual sealing medium 300 at the out-of-tolerance hole 210.
[0041] like Figure 2 As shown, in step S61, the surfaces of the out-of-tolerance hole 210 and the solid part 400 should be free of burrs and excess material. Dust and dirt should be removed from the bonding surfaces of the out-of-tolerance hole 210 and the solid part 400. The surfaces of the two out-of-tolerance holes 210 to be bonded should be carefully wiped with clean, acetone-soaked cotton to remove oil stains, cleaning until the cotton does not change color. Immediately after degreasing, the surfaces should be dried with cotton, and the surface of the out-of-tolerance hole 210 must not be touched with bare hands. The degreased parts 200 and 400 should be air-dried at room temperature for 15 minutes.
[0042] like Figure 3 As shown, in step S63, a layer of anaerobic adhesive is evenly applied to the bonding surface of the out-of-tolerance hole 210. Similarly, the annular groove 110 on the outer circle of the solid part 400 is also fully coated with anaerobic adhesive. In this embodiment, Loctite 609 anaerobic adhesive is used. Before applying the anaerobic adhesive, a temperature and humidity meter is used to check the temperature of the bonding area. The temperature should be within the range of 10 to 35 degrees Celsius. The relative humidity should be within the range of 40% to 70%, and the site should be well-ventilated, clean, and tidy.
[0043] In step S64, the solid part 400 with anaerobic adhesive is slowly assembled into the tolerance hole 210, rotating back and forth to ensure that the adhesive layer is evenly distributed on the mating surface, and to ensure radial uniform fit and axial assembly. After assembly, excess adhesive is wiped off with clean degreased cotton. The amount of adhesive applied should be just enough to squeeze out a ring of adhesive.
[0044] like Figure 4As shown, in step S8, after the seal passes the test, the seal is machined by a precision five-axis machining center. The oil inlet hole that meets the design requirements is directly machined on the seal according to the design process of the casing. Since the anaerobic adhesive is provided in the annular groove 110, the bonding force between the bushing 100 and the part 200 is increased, which can prevent the bushing 100 from loosening due to the cutting force.
[0045] Example 3 This embodiment is the third embodiment of the method for repairing out-of-tolerance holes 210. This embodiment is similar to the second embodiment, except that in step S62, heating the part 200 includes placing the part 200 in an electric furnace and heating it to 95~105°C for baking; the cooling process includes placing the solid part 400 in a pure nitrogen freezer for cooling.
[0046] In step S65, the room temperature curing time is greater than or equal to 120 minutes, and the baking curing temperature is 95~105℃ for 45~55 minutes. During baking curing, the electric furnace should be heated to the specified temperature before placing the part 200 into the furnace. After baking curing, excess adhesive should be wiped clean with a cotton cloth or cotton yarn to prevent it from corroding other parts of the part 200. After curing, visually inspect the bonded areas for any lumpy adhesive residue.
[0047] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.
[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for repairing out-of-tolerance holes, characterized in that, Includes the following steps: S1. Measure the parameters of the out-of-tolerance hole (210) and select the bushing (100) material according to the casing material; S2. The out-of-tolerance hole (210) is precision bored and enlarged. After the precision boring and enlargement is completed, the actual value of the final hole diameter and the actual value of the final hole depth of the out-of-tolerance hole (210) are measured. S3. Select the blank bar material according to the bushing (100) material, and perform rough turning and finish turning of the outer diameter of the blank bar material in sequence according to the actual value of the final hole diameter. S4. A ring groove (110) is machined on the outer circle of the finished blank bar. S5. Cut the blank bar into a solid part (400) according to the actual value of the final hole depth, and deburr the end of the solid part (400). S6. The solid part (400) that has been processed as described above is press-fitted into the tolerance hole (210) of the part (200) and then bonded and cured. S7. Perform a sealing test on the out-of-tolerance hole (210); S8. After the sealing test is passed, the solid part (400) is subjected to rough drilling, semi-fine boring and fine boring in sequence, so as to process an inner hole in the solid part (400) that meets the design size of the out-of-tolerance hole (210) to form the bushing (100).
2. The method for repairing out-of-tolerance holes according to claim 1, characterized in that, In step S2, when the depth of the out-of-tolerance hole (210) is less than 3mm, the final hole depth is made greater than or equal to 3mm by precision boring.
3. The method for repairing out-of-tolerance holes according to claim 1, characterized in that, In step S3, the outer circle is precision machined to the outer diameter dimension D, and the outer diameter dimension D satisfies: in, This represents the final actual aperture value. For the interference and .
4. The method for repairing out-of-tolerance holes according to claim 1, characterized in that, In step S4, at least one annular groove (110) is machined on the outer circle of the blank bar, with an axial width dimension of satisfy: in, The length dimension of the bushing (100) is equal to the actual value of the final hole depth.
5. The method for repairing out-of-tolerance holes according to claim 4, characterized in that, In step S4, when the length L of the bushing (100) is less than 5mm, the annular groove (110) is provided only once on the outer circle of the blank bar.
6. The method for repairing out-of-tolerance holes according to claim 4, characterized in that, In step S4, the axial position dimension L1 of the annular groove (110) satisfies: The radial depth h of the annular groove (110) is 0.04mm~0.05mm.
7. The method for repairing out-of-tolerance holes according to claim 1, characterized in that, In step S5, the end face of the solid part (400) is provided with a rounded edge, and the radius C of the rounded edge is less than or equal to 0.2 mm.
8. The method for repairing out-of-tolerance holes according to claim 1, characterized in that, Step S6 includes the following steps: S61. Check whether there are burrs on the surface of the out-of-tolerance hole (210) and the surface of the solid part (400). After removing the dust, perform degreasing treatment. Place the degreased parts (200) and solid parts (400) at room temperature to dry. S62. Heating the part (200) to enlarge the out-of-tolerance hole (210) or cooling the solid part (400) to reduce the outer diameter of the solid part (400); S63. A sealing medium (300) is uniformly coated on the surface of the out-of-tolerance hole (210) and the outer circumferential surface of the solid part (400); S64. Press the solid part (400) into the tolerance hole (210) with an interference fit, rotate the solid part (400) to keep the sealing medium (300) evenly distributed, and remove the overflowing sealing medium (300). S65. Place the part (200) at room temperature to cure, then bake it in an electric furnace and cool it with the furnace. After cooling, visually inspect the out-of-tolerance hole (210) to ensure there is no residual sealing medium (300).
9. The method for repairing out-of-tolerance holes according to claim 8, characterized in that, In step S62, heating the part (200) includes placing the part (200) in an electric furnace and heating it to 95~105°C for baking; the cooling process includes placing the solid part (400) in a pure nitrogen freezer for cooling.
10. The method for repairing out-of-tolerance holes according to claim 8, characterized in that, In step S65, the room temperature curing time is greater than or equal to 120 min, and the baking curing temperature is 95~105℃, and the time is 45~55 min.