Rapid electric spark machining clamp for outer ring block of aero-engine and clamping method

Abstract

The machining clamp comprises a base, a positioning block and a supporting plate are fixed to the upper end of the base, a restraining hole is formed in the positioning block, a positioning pin is matched with the restraining hole, a threaded hole is formed in the supporting plate and used for installing a twisting rod, and the front end of the twisting rod is assembled with a radial pressing block; the radial pressing block is of an arc-shaped structure. According to the clamping method, the positioning pin acts on the U-shaped groove of the outer ring block to quickly position the outer ring block in the circumferential direction, the outer ring block is axially restrained through the action of the axial datum plane of the positioning block, and the outer ring block is radially restrained through the action of the restraining face, the supporting plate, the twisting rod and the radial pressing block of the positioning block. The outer ring block is rapidly clamped, aligned and machined through rapid alignment of the alignment groove and the alignment face. And when the clamp is used for aligning once, the other outer ring blocks do not need to be repeatedly aligned again, electric spark machining can be carried out only by clamping, and the efficiency is improved by 53%.

Description

Technical Field

[0001] The invention belongs to the technical field of electrospark machining fixtures and clamping, and in particular relates to an electrospark rapid machining fixture for an outer ring block of an aero-engine and a clamping method. Background Art

[0002] The outer ring is a part of the low-pressure turbine guide vane of an aircraft engine. It is composed of 36 equal outer ring blocks, which are used to limit and constrain the outer casing assembly of the low-pressure turbine guide vane. There are three axial grooves in the annular groove of the outer contour of each outer ring block, such as Figure 1 and Figure 2 As shown, electric spark machining is required. The common clamping method currently used is to clamp the lower end of the outer ring block, and then align the cross sections at both ends for processing. Due to the large radius of the outer ring block, the error of aligning the cross sections at both ends is large, resulting in the groove processing size not meeting the design requirements. The 36 segments of outer ring blocks make up an outer ring part. The scrapping of one outer ring block makes the other outer ring blocks unusable, causing the entire outer ring to be scrapped, causing huge losses in manpower and financial resources. In addition, the parts need to be repeatedly fine-tuned and clamped during alignment. Each outer ring block needs to be clamped and aligned. It takes 40 minutes to process each outer ring block, and it takes 1440 minutes to process each outer ring. The processing efficiency is low and cannot meet the requirements of engine production tasks.

[0003] The current clamping and alignment method is to clamp the lower end face of the outer ring block with a pressure plate, and then align it through the cross section of the outer ring block. Since the lower end face of the outer ring block is narrow, it relies entirely on the lower end face for positioning and restraint, and the clamping is unstable. In addition, the outer ring block has a large radius, and the alignment error through the cross section of the outer ring block is large, and the reliability is poor. In order to ensure accurate alignment, repeated fine-tuning of the clamping is required, and each arc block processed must be repeatedly aligned, which is inefficient.

[0004] The Chinese invention patent with publication number CN114226896B discloses a positioning clamp for arc parts. The positioning clamp for arc parts of this scheme realizes accurate positioning of arc parts through arc positioning parts and limiters, improves processing quality, and then simplifies clamping operation and improves processing efficiency through elastic compression. Finally, through the modular design between the positioning seat and the arc positioning parts, the design and development cost of the arc part clamp is reduced, while the processing efficiency is improved. This clamp cannot realize one-time clamping and positioning, and is not suitable for the parts of this scheme. Summary of the invention

[0005] In order to solve the above problems, the present invention aims to provide an electrospark machining fixture and a clamping method for an outer ring block of an aircraft engine.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an aerospace engine outer ring block electrospark rapid processing fixture, including a base, a positioning block and a support plate are fixed to the upper end of the base, a constraint hole is opened on the positioning block, the constraint hole is equipped with a positioning pin, and a threaded hole is opened on the support plate for installing a torsion rod. The front end of the torsion rod is assembled with a radial pressure block, and the radial pressure block is an arc-shaped structure.

[0007] Preferably, the base is of a special-shaped structure and is symmetrical, with a number of positioning holes and screw holes provided on the base. The front end of the base is a support plate support surface, and the rear end of the base is a positioning block support surface. The positioning block support surface is raised relative to the support plate support surface, and a horizontal handle mounting hole is provided at the vertical end of the base for connecting the handle.

[0008] Preferably, two identical support plate positioning holes are opened in the middle area of ​​the support plate support surface, and two identical first screw holes are opened in the area outside the support plate positioning holes, and the two support plate positioning holes and the first screw holes are symmetrical relative to the center line of the base;

[0009] Two identical first positioning holes are opened on the center line of the positioning block support surface, and four identical second screw holes are opened in the outer area of ​​the first positioning holes. The second screw holes are symmetrical with respect to the center line of the base.

[0010] Preferably, the positioning block is an inverted T-shaped structure, the front end of the positioning block is an axial reference plane, a horizontal constraint hole is opened in the vertical direction of the positioning block, one side through which the constraint hole passes is an arc-shaped first constraint surface, a rectangular alignment groove is also provided in the uppermost area in the vertical direction, and two symmetrical positioning block positioning holes are opened on the base of the positioning block in the horizontal direction.

[0011] Preferably, the constraining hole is located directly above the center line of the base, and the center line of the alignment groove is located directly above the center line of the base.

[0012] Preferably, the positioning pin comprises three parts: a second constraint surface, a first fixed surface, and a second fixed surface. The first fixed surface of the positioning pin contacts the constraint hole of the positioning block to ensure that the axis of the positioning pin is directly above the center line of the base.

[0013] Preferably, the support plate is an L-shaped structure, mainly comprising a fourth vertical screw hole, a second positioning hole and a horizontal threaded hole, the threaded hole is located above the front face, and the axis of the threaded hole is located directly above the center line of the base.

[0014] Preferably, the support plate positioning hole and the second positioning hole of the support plate are assembled by positioning pins to accurately position the support plate, ensuring that the axis of the threaded hole of the support plate is directly above the center line of the base; the first screw hole and the fourth screw hole on the support plate are assembled by the first screw to completely fix the support plate on the base; the first positioning hole and the positioning block positioning hole on the positioning block are assembled and positioned by positioning pins to ensure that the constraint hole of the positioning block is directly above the center line of the base; the second screw hole and the third screw hole on the positioning block are fixedly connected to the base through the action of screws.

[0015] A method for clamping an outer ring block of an aero-engine by an electric spark processing fixture comprises the following steps:

[0016] Step 1: Clamp the outer ring block on the fixture, tighten the positioning pin to act on the U-shaped groove of the outer ring block, and the second constraint surface contacts the U-shaped groove of the outer ring block to quickly position the outer ring block in the circumferential direction;

[0017] Step 2: The outer ring block is axially and radially constrained. The outer ring block is axially constrained through the axial reference surface of the positioning block, and the outer ring block is radially constrained through the first constraint surface of the positioning block, the support plate, the torsion rod, and the radial pressure block;

[0018] Step 3: Align the outer ring block once, and quickly align it through the alignment groove and the alignment surface, so that the outer ring block can be quickly clamped and aligned for processing.

[0019] Preferably, the first constraint surface is an arc surface, and its polar radius is the same as the diameter of the outer circular surface of the outer ring block, so as to ensure that the first constraint surface fits the outer circular surface of the outer ring block;

[0020] The radial pressure block is an arc-shaped structure, and its polar radius is the same as the polar radius of the inner circle surface of the outer block. It contacts the inner circle surface of the outer block, so that the axial force of the torsion rod is evenly pressed on the outer ring block, thereby radially pressing and positioning the outer ring block.

[0021] Compared with the prior art, the present invention has the following advantages: the fixture and clamping method for rapid EDM machining of the outer ring block of an aircraft engine of the present invention can quickly position the outer ring block circumferentially by acting on the U-shaped groove of the outer ring block through the positioning pin, and can axially constrain the outer ring block through the axial reference surface of the positioning block, and radially constrain the outer ring block through the constraining surface, support plate, torsion rod, and radial pressure block of the positioning block. The outer ring block can be quickly clamped and aligned for machining by rapid alignment through the alignment groove and the alignment surface. And the fixture only needs to be aligned once, and the remaining outer ring blocks do not need to be repeatedly aligned again, and only need to be clamped for EDM machining, which improves the efficiency by 53%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings required for use in the description of the embodiments 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 these drawings without paying creative work.

[0023] Figure 1 The three-dimensional schematic diagram of the outer ring block in the present invention Figure 1 ;

[0024] Figure 2 The three-dimensional schematic diagram of the outer ring block in the present invention Figure 1 ;

[0025] Figure 3 It is a front view of the outer ring block clamped by the electrospark machining fixture of the present invention;

[0026] Figure 4 It is a side view of the outer ring block clamped by the electrospark machining fixture of the present invention;

[0027] Figure 5 A top view of the outer ring block clamped by the electrospark machining fixture of the present invention;

[0028] Figure 6 is a top view of the base in the present invention;

[0029] Figure 7 It is a front view of the base in the present invention;

[0030] Figure 8 It is a front view of the positioning block in the present invention;

[0031] Fig. 9 It is a side view of the positioning block in the present invention;

[0032] Fig.10 A top view of the positioning block in the present invention;

[0033] Fig.11 is a schematic diagram of a positioning pin in the present invention;

[0034] Fig.12 It is a front view of the support plate in the present invention;

[0035] Fig.13 It is a side view of the support plate in the present invention;

[0036] In the figure, 1-base; 2-positioning block; 3-support plate; 4-outer ring block; 5-radial pressure block; 6-positioning pin; 7-torsion rod; 8-first screw; 9-second screw; 10-positioning pin; 11-handle; 12-positioning block supporting surface; 13-support plate supporting surface; 14-support plate positioning hole; 15-first screw hole; 16-second screw hole; 17-first positioning hole; 18-handle mounting hole; 19-first constraint surface; 20-constraint hole; 21-positioning block positioning hole; 22-alignment groove; 23-third screw hole; 24-second constraint surface; 25-first fixing surface; 26-second fixing surface; 27-fourth screw hole; 28-alignment surface; 29-threaded hole; 30-second positioning hole; 31-axial reference surface. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0038] The present invention provides a fixture and a clamping method for rapid electrospark machining of an outer ring block of an aero-engine. Figure 3-5 The fixture mainly includes a base 1, a positioning block 2, a support plate 3, a positioning pin 6, a radial pressure block 5, and a torsion rod 7.

[0039] Reference Figure 6 and Figure 7 The base 1 is bilaterally symmetrical, and mainly has a support plate positioning hole 14, a first screw hole 15, a second screw hole 16, and a first positioning hole 17. It is used to support the positioning block 2 and the support plate 3, and ensure that the constraint hole 20 of the positioning block 2, the threaded hole 29 of the support plate 3, and the center line of the base are in the same plane.

[0040] The front end of the base 1 is a support plate support surface 13, which contacts the lower end surface of the support plate 3 and is used to support the support plate 3. There are two identical support plate positioning holes 14 in the middle area of ​​the support plate support surface 13, and the two support plate positioning holes 14 are symmetrical relative to the center line of the base 1. The support plate positioning holes 14 and the second positioning holes 30 of the support plate 3 are assembled through the positioning pins 10 to accurately position the support plate 3 and ensure that the axis of the threaded hole 29 of the support plate 3 is directly above the center line of the base 1. There are two identical first screw holes 15 in the area outside the support plate positioning holes 14, and the first screw holes 15 are symmetrical relative to the center line of the base. The first screw holes 15 and the fourth screw holes 27 on the support plate 3 are used by screws 8 to completely fix the support plate 3 on the base 1.

[0041] The rear end of the base 1 is a positioning block support surface 12, which is raised relative to the support plate support surface 13 to support the positioning block 2. There are two identical first positioning holes 17 on the center line of the positioning block support surface 12. The first positioning holes 17 and the positioning block positioning holes 21 on the positioning block 2 are assembled and positioned by positioning pins 10 to ensure that the constraint hole 20 of the positioning block is directly above the center line of the base 1. There are four identical second screw holes 16 in the area outside the positioning holes 17, which are symmetrical relative to the center line of the base. The second screw holes 16 and the third screw holes 23 on the positioning block 2 are fixedly connected to the base 1 by screws 9.

[0042] Reference Figure 8-Figure 10 The positioning block 2 is an inverted T-shaped structure, including a first constraint surface 19, a constraint hole 20, a positioning block positioning hole 21, a alignment groove 22, a third screw hole 23, and an axial reference surface 31. The constraint surface 19 is an arc surface, and the polar radius is the same as the diameter of the outer circumferential surface of the outer ring block 4, so as to ensure that the constraint surface 19 fits the outer circumferential surface of the outer ring block 4, so as to radially constrain the outer ring block 4.

[0043] The positioning block 2 has a constraint hole 20, which is located just above the center line of the base 1 and is used to assemble the positioning pin 6. The front end of the positioning block 2 is an axial reference surface 31, which contacts the lower end surface of the outer ring block to support and axially constrain the outer ring block to ensure that the outer ring block has good flatness. The upper end area of ​​the positioning block 2 has a rectangular alignment groove 22, the center line of which is just above the center line of the base 1, which is used to align the outer ring block.

[0044] Reference Fig.11 The positioning pin 6 includes three parts: the second constraint surface 24, the first fixed surface 25, and the second fixed surface 26. The fixed surface 25 of the positioning pin 6 contacts the constraint hole 20 of the positioning block 2 to ensure that the axis of the positioning pin is directly above the center line of the base 1. The second constraint surface 24 contacts the U-shaped groove of the outer ring block to axially constrain the outer ring block and ensure that the center line of the outer ring block is directly above the center line of the base 1.

[0045] Reference Fig.12 and Fig.13 The support plate 3 is an L-shaped structure, mainly including a fourth screw hole 27, a front face 28, a threaded hole 29, and a second positioning hole 30. The axis of the threaded hole 29 is located directly above the center line of the base 1, and is used to install the torsion rod 7. The front end of the torsion rod 7 is assembled with the radial pressing block 5. The radial pressing block 5 is an arc-shaped structure, and its polar radius is the same as the polar radius of the inner circle surface of the outer shape block. It contacts the inner circle surface of the outer shape block, so that the axial force of the torsion rod 7 is evenly pressed on the outer ring block, thereby radially pressing and positioning the outer ring block.

[0046] In summary, through the fixture and clamping method for rapid EDM machining of the outer ring block of an aircraft engine of the present invention, the positioning pin 6 acts on the U-shaped groove of the outer ring block to quickly position the outer ring block circumferentially, and the axial reference surface 31 of the positioning block 2 acts to constrain the outer ring block axially, and the first constraint surface 19 of the positioning block 2, the support plate 3, the torsion rod 7, and the radial pressure block 5 act to constrain the outer ring block radially. The outer ring block is quickly clamped and aligned through the alignment groove 22 and the alignment surface 28. And the fixture is used for alignment only once, and the remaining outer ring blocks do not need to be repeatedly aligned again. They only need to be clamped for EDM machining, which improves the efficiency by 53%.

[0047] The above is a detailed introduction to the electrospark machining fixture and clamping method of an aircraft engine outer ring block provided by the present invention. This article uses specific examples to illustrate the structure and working principle of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A fixture for rapid electrospark machining of an outer ring block of an aircraft engine, characterized in that: The invention comprises a base (1), a positioning block (2) and a support plate (3) are fixed to the upper end of the base (1), a constraint hole (20) is provided on the positioning block (2), a positioning pin (6) is matched with the constraint hole (20), a threaded hole (29) is provided on the support plate (3) for installing a torsion rod (7), the front end of the torsion rod (7) is assembled with a radial pressure block (5), and the radial pressure block (5) is an arc-shaped structure.

2. The aero-engine outer ring block electrospark rapid machining fixture according to claim 1 is characterized in that: The base (1) is of a special-shaped structure and is symmetrical. A plurality of positioning holes and screw holes are provided on the base (1). The front end of the base (1) is a support plate support surface (13), and the rear end of the base (1) is a positioning block support surface (12). The positioning block support surface (12) is raised relative to the support plate support surface (13). A horizontal handle mounting hole (18) is provided at the vertical end of the base (1) for connecting the handle (11).

3. The aerospace engine outer ring block electrospark rapid machining fixture according to claim 2 is characterized in that: Two identical support plate positioning holes (14) are provided in the middle area of ​​the support plate bearing surface (13), and two identical first screw holes (15) are provided in the area outside the support plate positioning holes (14), and the two support plate positioning holes (14) and the first screw holes (15) are symmetrical relative to the center line of the base (1); Two identical first positioning holes (17) are provided on the center line of the positioning block support surface (12), four identical second screw holes (16) are provided in the outer area of ​​the first positioning holes (17), and the second screw holes (16) are symmetrical relative to the center line of the base (1).

4. The aero-engine outer ring block electrospark rapid machining fixture according to claim 1, characterized in that: The positioning block (2) is an inverted T-shaped structure. The front end of the positioning block (2) is an axial reference surface (31). A horizontal constraint hole (20) is provided in the vertical direction of the positioning block (2). One side through which the constraint hole (20) passes is an arc-shaped first constraint surface (19). A rectangular alignment groove (22) is also provided in the uppermost region in the vertical direction. Two symmetrical positioning block positioning holes (21) are provided on the base of the positioning block (2) in the horizontal direction.

5. The aero-engine outer ring block electrospark rapid machining fixture according to claim 5 is characterized in that: The restraining hole (20) is located directly above the center line of the base (1), and the center line of the alignment groove (22) is located directly above the center line of the base (1).

6. The aero-engine outer ring block electrospark rapid machining fixture according to claim 1, characterized in that: The positioning pin (6) comprises three parts: a second constraint surface (24), a first fixing surface (25), and a second fixing surface (26). The first fixing surface (25) of the positioning pin (6) contacts the constraint hole (20) of the positioning block (2), ensuring that the axis of the positioning pin is directly above the center line of the base (1).

7. The aero-engine outer ring block electrospark rapid machining fixture according to claim 1, characterized in that: The support plate (3) is an L-shaped structure, mainly comprising a fourth vertical screw hole (27), a second positioning hole (30) and a horizontal threaded hole (29), the threaded hole (29) is located above the front face (28), and the axis of the threaded hole (29) is located directly above the center line of the base (1).

8. The aero-engine outer ring block electrospark rapid machining fixture according to claim 1, characterized in that: The support plate positioning hole (14) and the second positioning hole (30) of the support plate (3) are assembled through the positioning pin (10) to accurately position the support plate (3) and ensure that the axis of the threaded hole (29) of the support plate (3) is directly above the center line of the base (1); the first screw hole (15) and the fourth screw hole (27) on the support plate (3) are assembled through the first screw (8) to completely fix the support plate (3) on the base (1); the first positioning hole (17) and the positioning block positioning hole (21) on the positioning block (2) are assembled and positioned through the positioning pin (10) to ensure that the constraint hole (20) of the positioning block is directly above the center line of the base (1); the second screw hole (16) and the third screw hole (23) on the positioning block (2) are fixedly connected to the base (1) through the action of the screw (9).

9. A method for clamping an outer ring block of an aircraft engine using an electrospark machining fixture as claimed in any one of claims 1 to 8, characterized in that: The following steps are included: Step 1: Clamp the outer ring block (4) on the fixture, tighten the positioning pin (6) to act on the U-shaped groove of the outer ring block, and the second constraint surface (24) contacts the U-shaped groove of the outer ring block to quickly position the outer ring block in the circumferential direction; Step 2: The outer ring block is axially and radially constrained. The outer ring block is axially constrained through the axial reference surface (31) of the positioning block (2). The outer ring block is radially constrained through the first constraining surface (19) of the positioning block (2), the support plate (3), the torsion rod (7), and the radial pressure block (5); Step 3: The outer ring block (4) is aligned once, and is quickly aligned through the alignment groove (22) and the alignment surface (28), so that the outer ring block can be quickly clamped and aligned.

10. The clamping method of the aero-engine outer ring block electrospark rapid machining fixture according to claim 9, characterized in that: The first constraint surface (19) is an arc surface, and its polar radius is the same as the diameter of the outer circumferential surface of the outer ring block (4), so as to ensure that the first constraint surface (19) and the outer circumferential surface of the outer ring block fit together; The radial pressure block (5) is an arc-shaped structure, and its polar radius is the same as the polar radius of the inner circular surface of the outer shape block (4). It contacts the inner circular surface of the outer shape block, so that the axial force of the torsion rod (7) is evenly pressed on the outer ring block, thereby radially pressing and positioning the outer ring block (4).

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