Shaft housing mounting edge hole processing method

Abstract

The application discloses a shaft-shaped casing mounting edge hole processing method, which comprises the following steps: S1, installing an auxiliary clamping tool on a work platform and clamping the casing horizontally by using the auxiliary clamping tool; S2, adjusting the angle of the work platform so that the end face of the casing is perpendicular to the main shaft; S3, checking the center of the casing by the main shaft and setting the center position G54 of the part; S4, rough machining the edge hole of the end face of the casing; S5, checking the center of the casing by the main shaft again, judging whether the center of the casing is changed, and if the center of the casing is not changed, finishing the edge hole of the end face of the casing; and the auxiliary clamping tool comprises a radial positioning assembly for radial positioning of the casing and an axial positioning assembly for axial positioning of the casing. The application has the effect of improving the machining size precision of the edge hole of the shaft-shaped casing.

Description

Technical Field

[0001] This invention relates to the field of machining of aero-engine parts, and in particular, to a method for machining mounting holes on a shaft-shaped casing. Background Technology

[0002] The rear support casing welding assembly is a major load-bearing component of a certain type of aero-engine. The overall structure of the part is a long cylindrical shape, mainly composed of four welded parts: the front section of the rear support casing, the middle section of the rear support casing, the rear section of the rear support casing, and the expansion ring mounting groove of the rear support casing. After welding, the mounting edge holes on the end face of the casing need to be machined.

[0003] Currently, the common practice for machining mounting holes on the end faces of shaft-type parts is to use a vertical machining center. The shaft-type part is vertically mounted on the worktable, and the cutting tool, along with the spindle, machines the upper end face of the part from top to bottom. However, for rear support casings, this machining method presents several problems. Firstly, aero-engine casing-type parts are generally long and have large diameters. For example, the overall length of a rear support casing part for a certain type of engine reaches 1130.9 mm, and the maximum diameter is Φ405.2 mm. Currently, the maximum Z-axis travel of commonly used CNC machining centers is 1250 mm. The machining tool overhang is 150-200mm, while the part is 1130.9mm long, exceeding the machine tool travel distance and making machining impossible. Furthermore, because the part is a long cylindrical structure with a hollow, through-hole design and a wall thickness of 3mm, its rigidity is poor. The distance between the support / clamping point and the machining position is too great, making deformation likely. Even if a large machining center with sufficient travel distance could be found, machining the mounting holes on the end face of the casing would exert significant pressure on the thin wall of the casing, causing deformation. Additionally, tool vibration during machining makes dimensional accuracy difficult to guarantee. These issues result in a low pass rate for this machining process and a high quality risk. Summary of the Invention

[0004] This invention provides a method for machining mounting side holes in a shaft-shaped casing to solve the technical problem of low dimensional accuracy in machining mounting side holes in shaft-shaped casings.

[0005] According to one aspect of the present invention, a method for machining mounting holes on a shaft-shaped housing is provided, comprising the following steps: S1, installing an auxiliary clamping fixture on a work platform and using the auxiliary clamping fixture to horizontally clamp the housing; S2, adjusting the angle of the work platform so that the end face of the housing is perpendicular to the spindle; S3, using a dial indicator to align the center of the housing on the spindle and setting the center position of the part to G54; S4, rough machining the mounting holes on the end face of the housing; S5, using a dial indicator again on the spindle to determine whether the center of the housing has changed. If the center of the housing has not changed, then finishing machining the mounting holes on the end face of the housing; the auxiliary clamping fixture includes a radial positioning component for radial positioning of the housing and an axial positioning component for axial positioning of the housing.

[0006] Optionally, the radial positioning assembly includes a base and a clamping member disposed on the base. The base has a positioning groove for accommodating the housing. The clamping member includes a column, a pressure plate, and a locking block. The column is perpendicular to the housing axis. The pressure plate slides along the length of the column and extends above the positioning groove to clamp the housing in the positioning groove. The locking block is threadedly engaged with the column to clamp the pressure plate.

[0007] The use of auxiliary clamping fixtures for horizontal clamping of the housing includes the following steps: removing the pressure plate and installing the housing in the positioning groove; installing the pressure plate on the column and rotating the locking block to move the locking block downwards to press the housing.

[0008] Optionally, the clamping component further includes a support rod, which is arranged parallel to the column. One end of the support rod is fixedly connected to the base, and the other end of the support rod is used to support the pressure plate. The length of the support rod is adapted to the diameter of the casing. In the step of installing the pressure plate on the column and rotating the locking block to move the locking block downward to clamp the casing, the locking block is stopped when the pressure plate moves to contact the support rod.

[0009] Optionally, a gasket is embedded in the pressure plate at the position for contacting the casing, and the hardness of the gasket is less than that of the casing.

[0010] Optionally, the axial positioning assembly includes a clamping seat and a clamping plate. The clamping seat is used to fix the machine to the base or work platform. The clamping plate is provided with a locking bolt that is threadedly connected to the clamping seat. The edge of the end face of the machine housing to be processed is located between the clamping seat and the clamping plate. The horizontal clamping of the machine housing using the auxiliary clamping fixture further includes the following steps: moving the machine housing axially so that the edge of the end face of the machine housing to be processed contacts the clamping seat; installing the clamping plate and rotating the locking bolt so that the locking bolt is threadedly connected to the clamping seat.

[0011] Optionally, a protective protrusion is provided at the end of the clamping plate away from the housing; in the step of installing the clamping plate and rotating the locking bolt to make the locking bolt threaded onto the clamping seat, the rotation of the locking bolt is stopped after the protective protrusion contacts the clamping seat.

[0012] Optionally, in the step of adjusting the angle of the working platform to make the end face of the casing perpendicular to the spindle, the end face of the casing is checked by dial indicator. The end face runout is checked by dragging the dial indicator laterally and longitudinally on the end face of the casing. If the end face runout is greater than the preset value, the lateral adjustment is made by rotating the A-axis and the longitudinal adjustment is made by rotating the C-axis to ensure that the end face of the part is horizontal and the runout is not greater than the preset value.

[0013] Optionally, in the step of installing the pressure plate on the column and rotating the locking block to move the locking block downward to press the housing, a dial indicator needs to be used to observe whether there is any deformation of the parts before and after pressing. The change of the dial indicator needle before and after pressing is not allowed to exceed the preset standard.

[0014] Optionally, before using the auxiliary clamping fixture to horizontally clamp the housing, fill the housing cavity with EPE foam padding.

[0015] Optionally, multiple sets of the axial positioning components are evenly spaced along the circumference of the casing.

[0016] In summary, this application includes at least one of the following beneficial technical effects:

[0017] By using auxiliary clamping fixtures to horizontally clamp the casing, the problem of limited travel on general-purpose machining centers is solved, enabling the machining of parts that were previously impossible. Using dial indicators before and after clamping allows for timely detection of deformation of the casing parts during clamping, preventing scrapping due to excessive clamping force causing deformation beyond acceptable limits. Aligning the end faces of the casing parts before machining improves machining accuracy. The auxiliary clamping fixtures include radial and axial positioning components, which together support the casing, distributing the cutting force and preventing excessive deformation due to localized stress.

[0018] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the auxiliary clamping fixture according to a preferred embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the radial positioning component according to a preferred embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the axial positioning component according to a preferred embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the alignment and leveling process in a preferred embodiment of the present invention.

[0024] Legend:

[0025] 1. Base; 2. Clamping component; 21. Column; 22. Pressure plate; 23. Locking block; 24. Support rod; 31. Clamping seat; 32. Clamping plate; 33. Locking bolt; 4. Positioning groove. Detailed Implementation

[0026] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0027] The following is in conjunction with the appendix Figure 1 —4 provides further detailed description of this application.

[0028] This application discloses a method for machining mounting side holes in a shaft-shaped casing, including the following steps:

[0029] S1, Install auxiliary clamping fixture on the work platform and use the auxiliary clamping fixture to horizontally clamp the machine housing;

[0030] S2, Adjust the angle of the work platform so that the end face of the casing is perpendicular to the spindle;

[0031] S3, use a dial indicator to align the spindle to the center of the housing, and set the center position of the part G54;

[0032] S4, rough machining of the end face edge hole of the casing;

[0033] S5, check the spindle dial indicator again to determine if the center of the housing has changed. If the center of the housing has not changed, then finish machine the edge holes on the end face of the housing.

[0034] The auxiliary clamping fixture includes a radial positioning assembly for radial positioning of the casing and an axial positioning assembly for axial positioning of the casing.

[0035] Reference Figure 1In this embodiment, by using auxiliary installation fixtures, the casing can be horizontally clamped with the end of the casing to be processed facing the spindle and the end of the casing not to be processed extending into the space outside the machine tool travel, so that the tail of the part is exposed outside the machine tool worktable, making full use of the space outside the machine tool travel for clamping and fixing. The mounting holes of the casing undergo two machining processes: roughing and finishing, which improves machining accuracy. Before roughing, the casing is first aligned using a dial indicator to ensure its center is correct. After roughing and before finishing, the casing is aligned again using a dial indicator to check if its center has changed due to movement or deformation under the cutting force during roughing. If there is no change or the change is minimal and within the allowable accuracy range, finishing can proceed normally. If the casing centerline changes significantly after roughing, the tooling needs to be checked to see if loose clamping caused the casing to move during machining. After ruling out clamping-related factors, the casing perimeter is then aligned using a dial indicator to check for deformation. The radial and axial positioning components work together to support the casing, distributing the cutting force and preventing excessive deformation due to localized stress.

[0036] Reference Figure 2 The radial positioning assembly includes a base 1 and a clamping member 2 disposed on the base 1. The base 1 has a positioning groove 4 for accommodating the casing. The clamping member 2 includes a column 21, a pressure plate 22 and a locking block 23. The column 21 is perpendicular to the axial direction of the casing. The pressure plate 22 slides along the length of the column 21 and is in slidable engagement with the column 21. The pressure plate 22 extends above the positioning groove 4 to clamp the casing in the positioning groove 4. The locking block 23 is threadedly engaged with the column 21 to clamp the pressure plate 22.

[0037] The base 1 is bolted to the machine tool's worktable. The bottom end of the column 21 is welded to the base 1. The pressure plate 22 is horizontally positioned and slides in cooperation with the column 21. Sliding the pressure plate 22 upwards allows it to disengage from the column 21. To avoid interference from the pressure plate 22, before installing the housing, the pressure plate 22 is first moved upwards to disengage from the column 21. After installing the housing into the positioning slot 4, the pressure plate 22 is then installed on the column 21, and the locking block 23 is rotated to move downwards and press the housing. Optionally, multiple clamping elements 2 are spaced apart along the length of the housing to improve clamping stability. Optionally, a return spring is fitted on the column 21. One end of the return spring abuts against the base 1, and the other end contacts the pressure plate 22. When the pressure plate 22 is locked by the locking block 23, the return spring is compressed. When the locking block 23 is loosened, the pressure plate 22 moves upwards under the action of the return spring.

[0038] The clamping component 2 also includes a support rod 24, which is parallel to the column 21. One end of the support rod 24 is fixedly connected to the base 1, and the other end of the support rod 24 is used to support the pressure plate 22. The length of the support rod 24 is adapted to the diameter of the casing. During the step of installing the pressure plate 22 on the column 21 and rotating the locking block 23 to move it downwards and clamp the casing, the tightening of the locking block 23 should be stopped when the pressure plate 22 contacts the support rod 24. During this step, a dial indicator needs to be used to observe whether there is any deformation of the parts before and after clamping. The change in the dial indicator needle before and after clamping should not exceed the preset standard.

[0039] In this embodiment, the column 21 is located between the casing and the support column. The support column can limit the sliding stroke of the pressure plate 22, preventing the pressure plate 22 from moving too far downward when the locking force of the locking member is too large, which would cause large deformation of the casing. When one end of the pressure plate 22 contacts the casing, the other end of the pressure plate 22 also contacts the top of the support column at the same time, so that the pressure plate 22 will not move downward.

[0040] A shim is inlaid on the pressure plate 22 at the position where it contacts the casing. The hardness of the shim is less than that of the casing. The shim further reduces the risk of damaging the parts. In one specific embodiment, the shim is a copper sheet.

[0041] Reference Figure 1 and Figure 3 The axial positioning assembly includes a clamping seat 31 and a clamping plate 32. The clamping seat 31 is used to fix it to the base 1 or the working platform. The clamping plate 32 is provided with a locking bolt 33 that is threadedly connected to the clamping seat 31. The edge of the end face of the housing to be machined is located between the clamping seat 31 and the clamping plate 32. Optionally, multiple sets of axial positioning assemblies are evenly spaced along the circumference of the housing, so that the housing can be clamped and fixed in all directions around the circumference. Optionally, a protective boss is provided at the end of the clamping plate 32 away from the housing. The protective boss can prevent the clamping plate 32 from clamping too tightly and causing deformation of the end face of the housing.

[0042] The use of auxiliary clamping tooling for horizontal clamping housing also includes the following steps: moving the housing axially so that the edge of the end face of the housing to be processed contacts the clamping seat 31; installing the clamping plate 32 and rotating the locking bolt 33 so that the locking bolt 33 is threaded onto the clamping seat 31; stopping the rotation of the locking bolt 33 after the protective protrusion contacts the clamping seat 31.

[0043] Reference Figure 4In the step of adjusting the work platform angle to make the end face of the housing perpendicular to the spindle, the end face of the housing is checked by using a dial indicator. The end face runout is checked laterally and longitudinally by dragging the dial indicator. If the runout exceeds the preset value, the lateral adjustment is made by rotating the A-axis, and the longitudinal adjustment is made by rotating the C-axis, ensuring the end face of the part is horizontal and the runout does not exceed the preset value. During clamping and pressing, a dial indicator is used to observe whether there is any clamping deformation of the part before and after clamping. The change in the dial indicator needle before and after clamping should not exceed 0.02. After clamping the part, the end face of the part is checked by using a dial indicator. The end face runout is checked laterally and longitudinally by dragging the dial indicator. It should not exceed 0.02. If it exceeds this value, the lateral adjustment is made by rotating the C-axis, and the longitudinal adjustment is made by rotating the C-axis, ensuring the end face of the part is horizontal and the runout does not exceed 0.02. Then, the spindle dial indicator is used to align the inner hole of the part. The runout of the four symmetrical points of the part should not exceed 0.02, thus aligning the center and setting the center position of the part to G54.

[0044] Optionally, before using the auxiliary clamping tool to horizontally clamp the housing, fill the housing cavity with EPE pearl cotton foam board. The foam thickness should be no less than 35mm. This can increase the rigidity of the parts, absorb shock, and prevent the parts from rebounding during processing. During the filling process, a hand force of no less than 20N should be used to press the foam board to make the foam board tighten the housing cavity.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of machining a boss hole for a shaft-shaped case mounting edge, characterized by, Includes the following steps: S1, Install auxiliary clamping fixture on the work platform and use the auxiliary clamping fixture to horizontally clamp the machine housing; S2, Adjust the angle of the work platform so that the end face of the casing is perpendicular to the spindle; S3, use a dial indicator to align the spindle to the center of the housing, and set the center position of the part G54; S4, rough machining of the end face edge hole of the casing; S5, check the spindle dial indicator again to determine if the center of the housing has changed. If the center of the housing has not changed, then finish machine the edge holes on the end face of the housing. The auxiliary clamping fixture includes a radial positioning assembly for radial positioning of the casing and an axial positioning assembly for axial positioning of the casing. The radial positioning assembly includes a base (1) and a clamping member (2) disposed on the base (1). The base (1) has a positioning groove (4) for accommodating the casing. The clamping member (2) includes a column (21), a pressure plate (22), and a locking block (23). The column (21) is perpendicular to the axial direction of the casing. The pressure plate (22) slides along the length of the column (21) and is in slidable engagement with the column (21). The pressure plate (22) extends above the positioning groove (4) to clamp the casing in the positioning groove (4). The locking block (23) is threadedly engaged with the column (21) to clamp the pressure plate (22). The use of auxiliary clamping fixtures for horizontal clamping of the housing includes the following steps: Remove the pressure plate (22) and install the casing into the positioning slot (4); Install the pressure plate (22) on the column (21), rotate the locking block (23) to move the locking block (23) downward to press the housing; The axial positioning assembly includes a clamping seat (31) and a clamping plate (32). The clamping seat (31) is used to fix it on the base (1) or the working platform. The clamping plate (32) is provided with a locking bolt (33) that is threadedly connected to the clamping seat (31). The edge of the end face to be processed of the casing is located between the clamping seat (31) and the clamping plate (32). The horizontal clamping housing using auxiliary clamping fixtures also includes the following steps: Move the housing along the axial direction so that the edge of the end face of the housing to be processed contacts the clamping seat (31); Install the clamping plate (32) and rotate the locking bolt (33) so that the locking bolt (33) is threaded onto the clamping seat (31); In the step of installing the pressure plate (22) on the column (21) and rotating the locking block (23) to move the locking block (23) downward to press the housing, it is necessary to use a dial indicator to observe whether there is any pressing deformation of the parts before and after pressing. The change of the dial indicator before and after pressing is not allowed to exceed the preset standard.

2. The method for machining mounting side holes of the shaft-shaped casing according to claim 1, characterized in that, The clamping component (2) also includes a support rod (24), which is arranged parallel to the column (21). One end of the support rod (24) is fixedly connected to the base (1), and the other end of the support rod (24) is used to support the pressure plate (22). The length of the support rod (24) is adapted to the diameter of the casing. In the step of installing the pressure plate (22) on the column (21) and rotating the locking block (23) to move the locking block (23) downward to press the housing, when the pressure plate (22) moves to contact the support rod (24), the tightening of the locking block (23) is stopped.

3. The method for machining mounting side holes of the shaft-shaped casing according to claim 2, characterized in that, The pressure plate (22) is fitted with a gasket at the position for contacting the casing, and the hardness of the gasket is less than that of the casing.

4. The method for machining mounting side holes of the shaft-shaped casing according to claim 3, characterized in that, The clamping plate (32) is provided with a protective protrusion at the end away from the casing; In the step of installing the clamping plate (32) and rotating the locking bolt (33) so that the locking bolt (33) is threaded onto the clamping seat (31), the rotation of the locking bolt (33) is stopped after the protective protrusion contacts the clamping seat (31).

5. The method for machining mounting side holes of the shaft-shaped casing according to claim 4, characterized in that: In the step of adjusting the angle of the working platform to make the end face of the casing perpendicular to the spindle, the end face of the casing is checked by using a dial indicator. The end face runout is checked by dragging the dial indicator horizontally and vertically on the end face of the casing. If the end face runout is greater than the preset value, the horizontal adjustment is made by rotating the A-axis, and the vertical adjustment is made by rotating the C-axis to ensure that the end face of the part is horizontal and the runout is not greater than the preset value.

6. The method for machining mounting side holes of the shaft-shaped casing according to claim 1, characterized in that, Before using the auxiliary clamping fixture to horizontally clamp the housing, fill the housing cavity with EPE foam padding.

7. The method for machining mounting side holes of the shaft-shaped casing according to claim 6, characterized in that, The axial positioning components are arranged in multiple sets at even intervals along the circumference of the casing.

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