Method for repairing and machining double-sided blind hole bearing bush of aero-engine gearbox shell

Abstract

The invention relates to a method for repairing and machining a double-sided blind hole bearing bush of an aero-engine gear box shell, and solves the technical problems that the position precision of a machined hole cannot meet the requirement, and out-of-tolerance and repair are easy to occur. Comprising the following steps: selecting a repair processing reference, selecting two holes in a front shell as reference holes, and selecting a combination surface of the reference holes and a rear shell as a reference surface; two holes in the rear shell are selected as reference holes, and the combination surfaces of the reference holes and the front shell are selected as reference surfaces; a three-dimensional repairing and machining model is established, the position relation between shafting holes and the precision requirement are guaranteed, a model graph is automatically driven to change according to actually-measured reference hole coordinates, a new repairing and machining model graph is formed, and the coordinates of other holes are read into a machine tool; machining of linings of the front shell and the rear shell is completed respectively; and the front shell and the rear shell are combined, the coaxiality of the output axis lining and the base body hole is checked, and if the coaxiality is not qualified, the positioning pin on the combination face is replaced to enable the coaxiality to be qualified. The method is high in repairing efficiency, short in period and traceable in quality.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engine gearbox repair, and particularly relates to a repair processing method for a double-sided blind hole bearing bushing of an aero-engine gearbox housing. Background Art

[0002] The aero-engine gearbox housing is an important basic component, which connects parts such as gear shafts, bearings, and bushings together according to certain mutual relationships and moves coordinately according to a certain transmission relationship. The processing quality of the gearbox housing assembly directly affects the assembly accuracy, motion accuracy, service performance, and life of the gearbox. When repairing or troubleshooting the gearbox, there are problems such as eccentric wear and deformation of the bearing bushings, and replacement and repair must be carried out. The dimensional tolerance of the bearing bushing hole is small, and the positioning accuracy requirement of the shaft system hole is high. The two double-sided blind holes (i.e., no holes are opened on the outside of the housing) of the bushings on the 2nd and 4th shafts cannot combine the housing to achieve one-cut processing, and only split processing can be carried out. It is extremely difficult to ensure the coaxiality, and the position accuracy of the shaft system hole is difficult to meet the requirements. The repair processing after replacing the bushing is difficult, has a long cycle, and the processing quality is unstable. Summary of the Invention

[0003] The invention provides a repair processing method for a double-sided blind hole bearing bushing of an aero-engine gearbox housing to solve the technical problems that the position accuracy of the processed holes cannot meet the requirements and it is easy to have out-of-tolerance and rework problems in the repair of the aero-engine gearbox housing bearing bushing.

[0004] The purpose of the invention is achieved through the following technical solutions:

[0005] A repair processing method for a double-sided blind hole bearing bushing of an aero-engine gearbox housing, where some shaft system holes of the gearbox are double-sided blind holes and some shaft system holes output transmission accessories unidirectionally, includes the following steps:

[0006] S1. Select the machining reference for the shaft system holes of the gearbox repair

[0007] For the front housing and the rear housing, select two shaft holes with outputs as the hole system positioning machining references respectively, and at the same time, select holes in different hole systems for the front housing and the rear housing; select the joint surface of the front housing and the rear housing as the reference surface;

[0008] S2. Establish a repair processing model for the gearbox housing

[0009] Taking the selected shaft system holes of the front housing as the reference, according to the shaft system position relationship in the design drawing, use 3D software to establish the coordinates of the remaining shaft system holes of the front housing; taking the selected shaft system holes of the rear housing as the reference, according to the shaft system position relationship in the design drawing, use 3D software to establish the coordinates of the remaining shaft system holes of the rear housing; the coordinates of the reference holes are obtained by measurement and installation on the machine tool;

[0010] During 3D modeling, the absolute dimensions in the product drawing are converted into relative dimensions, that is, the absolute coordinate angles are converted into relative angles between the holes, and the coordinates of the model are converted according to the principle of one plane and two holes positioning;

[0011] S3. Proofread the repair and machining model of the gearbox housing

[0012] Establish the front housing and rear housing models in one coordinate system. Based on the two reference holes of the front housing or rear housing, improve the equal constraint on the distance between the corresponding two hole positions of the two housings, measure the corresponding angles of one of the reference holes in the front housing and rear housing, and check the hole position difference of one of the reference holes in the front housing and rear housing. Meeting the position tolerance requirements indicates that the repair and machining model can be used;

[0013] S4. Instantiate the repair and machining model

[0014] Adopt the method of expressions in modeling, input the coordinates of the reference holes of the rear housing and front housing into the values of the expressions, drive to form a new model drawing, the coordinates of the remaining holes will change automatically, read the coordinate values of the holes, write them into the machine tool program for machining, and complete the machining of the bearing bushing holes according to the coordinate values;

[0015] S5. Positioning pin adjustment

[0016] The original positioning pin is used to adjust and correct the relative position after the combination of the front and rear housings. When necessary, change the position of the positioning pin during the repair process. The change method is: according to the calculated coordinates of the rear / front housing holes, adjust the position of the front / rear housing so that the two reference holes of the front / rear housing are consistent with the corresponding two hole positions of the rear / front housing. If the requirements are not met, re-machine the positioning pin or holes. The diameter of the positioning pin is increased to not exceed Ф9.5mm, which is an acceptable range;

[0017] S6. Check the coaxiality of the output shaft system hole bushings

[0018] After machining, check the coaxiality of the reference hole shaft system bushings and the matrix holes. After the coaxiality meets the requirements, deliver it to the warehouse for storage.

[0019] The present invention shortens the cycle of the gearbox housing. One housing forms one model drawing, the quality is traceable, and the failure rate is reduced. Description of the drawings

[0020] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0021] Figure 1 is the structural block diagram of a method for repairing and machining double-sided blind hole bearing bushings of an aeroengine gearbox housing according to the present invention;

[0022] Figure 2 Schematic diagram of the gearbox housing structure according to an embodiment of the present invention, wherein Fig. a is a sectional view taken along line A-A of Fig. b;

[0023] Figure 3 Schematic diagram of the repair and machining model according to an embodiment of the present invention, wherein Fig. a is the front housing and Fig. b is the rear housing;

[0024] In the figure, 1, 2, 3, 4, 5, 6 are shafting position numbers, 7, 8 are positioning pins (holes), 100 is the front housing, 101, 102, 103, 104, 105, 106 are bearing bushes on the front housing, 200 is the rear housing, 201, 202, 203, 204, 206 are bearing bushes on the rear housing, 1030, 1060, 2010, 2050 are axis matrix holes. Detailed implementation manners

[0025] As Figures 1-3 shown, the present invention provides a repair and machining method for double-sided blind hole bearing bushes of an aeroengine gearbox housing, which involves 6 shafting holes of the gearbox, numbered 1 to 6 respectively, wherein the 2nd and 4th shafting holes are double-sided blind holes, and the 1st, 3rd, 5th, and 6th shafting holes output transmission accessories unidirectionally, including the following steps:

[0026] Select the machining reference for the repaired shafting holes of the gearbox. Generally, one surface (joint surface) and two holes (bearing bush holes or pin shaft holes) are selected for shafting hole positioning. When designing the rear housing, the 5th hole and the 3rd hole are selected as shafting positioning points. The lateral distance between the holes is 160 mm, the longitudinal distance is 37 mm, and the linear distance between the holes is 164.2 mm; calculate the lateral distance between the 5th hole and the 1st hole, which is 177.4 mm, the longitudinal distance is 45.8 mm, and the linear distance between the holes is 183.2 mm; actually measure the lateral distance between the 1st and 5th holes of a certain rear housing, which is 180 mm, the longitudinal distance is 34 mm, and the linear distance between the holes is 183.2 mm. It can be seen that the linear distance between the two holes is equal while the longitudinal and lateral distances are not equal. There is a difference between the actually measured longitudinal and lateral distances between the 5th hole and the 1st hole and the design. If the design reference is maintained for repair, the position of the 1st hole must be changed, and the external output hole of the 1st hole is the accessory installation stop. It is necessary to correct the dimensions of the accessory installation stop and related connecting parts, which will cause the housing to lose its repair value. Therefore, the repair of the gearbox housing is a process of restoring the manufacturing state, rather than the design state. When repairing the gearbox housing, it is a feasible method to select the shaft hole with output as the hole system positioning reference to facilitate ensuring the connection structure of the external accessories of the gearbox, and the internal shafting holes ensure the relationship between the shaftings by machining the bearing bush holes.

[0027] Establish a repair and machining model for the gearbox housing. For the front housing, taking the shaft holes of axes 3 and 6 as the reference, and according to the shaft system position relationship in the design drawing, use 3D software to establish the shaft holes of axes 1, 2, 4, and 5; for the rear housing, taking the shaft holes of axes 1 and 5 as the reference, and according to the shaft system position relationship in the design drawing, use 3D software to establish the shaft holes of axes 2, 3, 4, and 6. For 3D modeling, it is necessary to convert the absolute dimensions in the product drawing into relative dimensions, mainly converting the absolute coordinate angles into relative angles between the holes. The coordinates of the model are converted according to the idea of locating with one plane and two holes. The coordinates of the reference holes are obtained by measurement when installed on the machine tool. In this way, a repair and machining model for the gearbox housing is established.

[0028] Check the repair and machining model of the gearbox housing. As Figure 3 shown, for the established repair and machining models of the front housing and the rear housing, the shaft holes should be in a mirror image relationship with each other. By connecting the holes one by one to check the model, it is found that the relevant angles between the shaft holes of axes 1 and 2 and other shaft holes differ by about 0.1 degree. When checking the position of the bushing of hole 1, it differs by 0.8 mm, and the deviation is too large; establish the models of the front housing and the rear housing in a coordinate system, and add an equal constraint improvement to increase the distance between the positions of holes 1 and 6 of the two housings (that is, connect the positions of holes 1 and 6 of the front housing and adjust it to be equal to the distance between the positions of holes 1 and 6 of the rear housing), measure the corresponding angles, and the difference is about 0.0005 degree. When checking the position of hole 1, it differs by 0.004 mm, meeting the position tolerance requirements, indicating that the repair and machining model can be used.

[0029] Instantiate the repair and machining model. After the front housing and the rear housing are clamped on the machine tool, it is necessary to instantiate the model onto the machine tool. That is, reflect the actual position of one plane and two holes of the rear housing clamped on the machine tool onto the model, and map the relative positions (coordinates) between the bushing holes determined by the model onto the machine tool, that is, the instantiation conversion of the model. If modeling according to the actual position of one plane and two holes every time, it will surely take a lot of time. Here, the method of expressions in modeling is adopted, that is, input the coordinates of holes 1 and 5 of the rear housing and holes 3 and 6 of the front housing into the value of the expression, drive to form a new model drawing, and the coordinates of the remaining holes will change automatically. Read the coordinate values of the holes and write them into the machine tool program for machining. The instantiation process is within 20 minutes. Machine the bearing bushing holes according to the coordinate values.

[0030] Adjust the positioning pins. The original positioning pins are used to adjust and correct the relative positions after the combination of the front and rear housings. When necessary, change the positions of the positioning pins during the repair process. According to the calculated coordinates of the holes of the rear housing, adjust the position of the front housing to make the positions of holes 3 and 6 consistent. If the requirements are not met, re-machine the positioning pin (hole), and increase the diameter of the positioning pin to not exceed Ф9.5 mm, which is an acceptable range.

[0031] Output shaft system hole bushing coaxiality inspection. After machining, check the coaxiality of the bushings and matrix holes of shafts 1, 5, 3, and 6. After the coaxiality meets the requirements, deliver it to the warehouse for storage.

[0032] Embodiment:

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0034] Figure 1 is a structural block diagram of a repair machining method for a double-sided blind hole bearing bushing of an aeroengine gearbox housing according to a preferred embodiment of the present invention; Figure 2 is a schematic structural diagram of an aeroengine gearbox housing according to a preferred embodiment of the present invention.

[0035] The repair machining method of this embodiment includes the following steps:

[0036] Install the front housing joint surface facing up on the machine tool workbench, adjust so that the joint surface runout does not exceed 0.02 mm, align the runout of holes 1030 and 1060 to be no greater than 0.02 mm, and read the center coordinates of these two holes. Install the rear housing joint surface facing up on the machine tool workbench, adjust so that the joint surface runout does not exceed 0.02 mm, align the runout of holes 2010 and 2050 to be no greater than 0.02 mm, and read the center coordinates of these two holes.

[0037] Figure 3 is a repair machining model of the embodiment. Input the center coordinates of holes 1030, 1060, 2010, and 2050 into the three-dimensional model for calculation. This model drives the graphic change according to the reference hole coordinates after the actual housing is installed on the machine tool, and automatically forms the new model hole coordinates. One housing is one product model drawing; read out the center coordinates of the bushing holes of 101, 102, 104, 105, 202, 203, 204, and 206, and use special software to write the coordinate values into the machine tool machining program.

[0038] For the 6 bushings 101, 102, 103, 104, 105, and 106 of the front housing, complete the machining according to the read hole center coordinates. For the 5 bushings 201, 202, 203, 204, and 206 of the rear housing, complete the machining according to the read hole center coordinates.

[0039] After machining, combine the front housing onto the rear housing, check the coaxiality of the two bushings and the matrix holes on the 3rd and 6th axes. If the inspection is unqualified, remove the 7th and 8th positioning pins on the joint surface, move the front housing to adjust the coaxiality of the bushings on the 3rd and 6th axes to be qualified, ream the positioning pin holes, and install the enlarged positioning pins.

[0040] Turn the housing over and check the coaxiality of the two bushings and the base holes on the 1st and 5th axes. If the inspection is unqualified, readjust the position of the positioning pins (no unqualified situation has been encountered during the turnover inspection).

[0041] After checking that the coaxiality of the 3rd, 6th, 1st, and 5th axes is qualified, deliver it to the warehouse for storage and the work is completed.

[0042] The above has introduced in detail the repair and processing method of the double-sided blind hole bearing bushings of the aeroengine gearbox housing of the present invention. Specific embodiments are applied in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only for understanding the method and core idea of the present invention. The above is only the preferred implementation manner of the present invention. It should be understood that the present invention is not limited to the form disclosed in this article, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described in this article through the above teachings or the technology or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A repair and machining method for a double-sided blind hole bearing bushing of an aeroengine gearbox housing. Some shaft system holes of the gearbox are double-sided blind holes, and some shaft system holes output transmission accessories unidirectionally. The characteristics are as follows: It includes the following steps: S1. Select the machining reference for the shaft system holes of the gearbox repair For the front housing and the rear housing, select two shaft holes with outputs as the machining reference for the hole system positioning. At the same time, the front housing and the rear housing select holes of different hole systems; S2. Establish the repair machining model of the gearbox housing Taking the selected shaft system holes as the reference, according to the shaft system position relationship in the design drawing, use 3D software to establish the coordinates of the remaining shaft system holes of the front housing; taking the selected shaft system holes as the reference, according to the shaft system position relationship in the design drawing, use 3D software to establish the coordinates of the remaining shaft system holes of the rear housing; the coordinates of the reference holes are obtained by measurement and installation on the machine tool; S3. Proofread the repair machining model of the gearbox housing Establish the models of the front housing and the rear housing in one coordinate system. Based on the two reference holes of the front housing or the rear housing, perform equal constraint improvement on the distance between the corresponding two hole positions of the two housings, measure the corresponding angles of one of the reference holes in the front housing and the rear housing, and check the hole position difference of one of the reference holes in the front housing and the rear housing. If the position tolerance requirements are met, it indicates that the repair machining model can be used; S4. Instantiate the repair machining model Adopt the method of expressions in modeling, input the coordinates of the reference holes of the rear housing and the front housing into the values of the expressions, drive to form a new model diagram, the coordinates of the remaining holes will change automatically, read the coordinate values of the holes, write them into the machine tool program for machining, and complete the machining of the bearing bushing holes according to the coordinate values; S5. Output the coaxiality inspection of the shaft system hole bushings After machining, conduct the coaxiality inspection of the reference hole shaft system bushings and the matrix holes. After the coaxiality meets the requirements, deliver it to the warehouse for storage.

2. A repair and machining method for a double-sided blind hole bearing bushing of an aeroengine gearbox housing according to claim 1, characterized in that: The original positioning pins are used to adjust and correct the relative positions after the combination of the front and rear housings. When necessary, change the positions of the positioning pins during the repair process. The change method is: according to the calculated coordinates of the rear / front housing holes, adjust the positions of the front / rear housings to make the two reference holes of the front / rear housings consistent with the corresponding two hole positions of the rear / front housings. If the requirements are not met, re-machine the positioning pins or holes.

3. A repair and machining method for a double-sided blind hole bearing bushing of an aeroengine gearbox housing according to claim 1, characterized in that: In step S2, during 3D modeling, convert the absolute dimensions in the product drawing into relative dimensions, that is, convert the absolute coordinate angles into the relative angles between the holes, and convert the coordinates of the model according to the principle of one plane and two holes positioning.

4. A repair and machining method for a double-sided blind hole bearing bushing of an aeroengine gearbox housing according to claim 1, characterized in that: In step S4, during machining: Install the front housing with the joint surface facing up on the machine tool workbench, adjust to make the joint surface runout not exceed 0.02 mm, align the runout of the two reference holes not greater than 0.02 mm, and read the center coordinates of these two holes; install the rear housing with the joint surface facing up on the machine tool workbench, adjust to make the joint surface runout not exceed 0.02 mm, align the runout of the two reference holes not greater than 0.02 mm, and read the center coordinates of these two holes.

Images