Welding and machining tool and method for bolt holes of rear flange of APU air inlet casing

Abstract

The invention discloses a welding and machining tool and method for a bolt hole of a rear flange of an air inlet casing of an auxiliary power unit (APU), and relates to the technical field of welding machining. The positioning disc is used for being detachably connected with a front flange of the air inlet casing, the pressing plate is used for being pressed on a rear flange of the air inlet casing, a supporting disc used for supporting the inner wall of the air inlet casing is arranged between the positioning disc and the pressing plate, and the positioning disc, the supporting disc and the pressing plate are connected through a main shaft. According to the welding and machining method for the rear flange bolt hole of the APU air inlet casing, the overall shape of the air inlet casing can be kept in the welding process, the air inlet casing can be fixed in the machining process, and deformation of the air inlet casing caused by fixing of the air inlet casing is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of welding processing, and in particular to a welding and machining tool and method for bolt holes of a rear flange of an APU air intake casing. Background Art

[0002] The aviation auxiliary power unit (APU) mainly provides power and air for the aircraft on the ground and in the air. The two ends of the air intake casing are connected to the load section and the air intake section of the APU, which plays the role of introducing external air into the load section and the air intake section.

[0003] The air intake casing is a cylindrical ring made of aluminum alloy. Its rear flange is connected to the power section diffuser casing by bolts. Due to the vibration during the operation of the APU, the bolt holes of the rear flange are prone to radial cracking. During the APU overhaul, the fault needs to be repaired by welding and the bolt hole size needs to be restored by machining.

[0004] Due to the low melting point, high thermal expansion coefficient and good thermal conductivity of aluminum alloy, the softening problem of aluminum alloy during welding is relatively serious. Therefore, when there is no anti-deformation tooling protection, the air intake casing is very likely to deform by flanging and other deformations during the welding repair of the rear flange bolt hole. In mild cases, rework is required, and in severe cases, the parts are scrapped. In addition, since the air intake casing may have a certain degree of roundness change after being disassembled from the APU, the center position of each bolt hole is offset. Therefore, when the bolt hole size is restored by machining after welding, the inner diameter of the air intake casing needs to be controlled to ensure the position size of the bolt hole after machining. Summary of the invention

[0005] The object of the present invention is to provide a welding and machining tool and method for the bolt holes of the rear flange of an APU air intake casing, which can not only maintain the overall shape of the air intake casing during the welding process, but also fix the air intake casing during the machining process and avoid deformation of the air intake casing caused by fixing the air intake casing.

[0006] In order to solve the above technical problems, the present invention adopts the following solutions: In the first aspect, a welding and machining tool for bolt holes of the rear flange of an APU air intake casing comprises a positioning plate for detachably connecting with the front flange of the air intake casing and a pressure plate for pressing on the rear flange of the air intake casing, a support plate for supporting the inner wall of the air intake casing is provided between the positioning plate and the pressure plate, and the positioning plate, the support plate and the pressure plate are connected by a main shaft. The support plate is arranged near the pressure plate. A chuck for being grasped by a claw on a machine tool is provided on the side of the positioning plate facing away from the pressure plate, the chuck is coaxially arranged with the positioning plate, the outer diameter of the chuck is smaller than the outer diameter of the positioning plate, and weight-reducing holes for reducing the overall weight of the positioning plate are uniformly hollowed out around the chuck on the positioning plate, and fastening bolt holes are uniformly arranged around the area where the weight-reducing holes are located on the positioning plate, the fastening bolt holes correspond to the bolt holes on the front flange of the air intake casing one by one, and the front flange of the air intake casing is fixed to the positioning plate by a circle of axial bolts passing through the fastening bolt holes and the bolt holes of the front flange, so as to realize the detachable connection between the front flange of the air intake casing and the positioning plate. All bolts are equipped with corresponding nuts, which is common knowledge and will not be elaborated. The main shaft is coaxially arranged with the positioning plate, support plate and pressure plate. Its function is that the air intake casing can be fixed on the positioning plate through the setting of the positioning plate; through the setting of the pressure plate, it can be pressed on the rear flange of the air intake casing to avoid the phenomenon of flanging of the rear flange of the air intake casing during welding; through the setting of the support plate, the inner wall of the air intake casing can be supported to ensure the roundness and processing rigidity of the air intake casing during machining.

[0007] Furthermore, at least three support members for contacting the inner wall of the air intake casing are arranged in a ring shape on the support plate, a spring is arranged between the support member and the support plate, and a positioning member for fixing the position of the support member is arranged on the support plate. Its function is that since vibration is easy to be generated during machining, if an integral rigid structure is used to support the inner wall of the air intake casing, it is easy to cause deformation of the air intake casing, affecting the machining flatness of the rear flange plane of the air intake casing; through the setting of the positioning member, the distance that the support member extends outward can be limited, so that when the support member is at the maximum distance of extending outward, the circular contour surrounded by the outermost ends of all the support members matches the inner wall of the air intake casing.

[0008] Furthermore, the support member includes a support block for directly contacting the inner wall of the air intake casing and a push rod connected to the support rod. The support plate is provided with a push rod groove for embedding the push rod and a support block groove for embedding the support block. The width of the push rod groove is smaller than the width of the support block groove. The support block and the push rod are connected by a fixing pin that penetrates the push rod and the support block simultaneously along the radial direction of the push rod. The push rod is cylindrical, and the support block has a cylindrical surface whose curvature matches the inner wall of the air intake casing and a cylinder for embedding into the push rod. The fixing pin penetrates the cylinder and the push rod to connect the support block with the push rod. One end of the support block of the push rod is provided with a supporting surface for supporting a spring embedded in the push rod, and the outer diameter of the spring matches the inner diameter of the push rod. The push rod groove is in the shape of a cylindrical groove, the inner diameter of the push rod groove matches the outer diameter of the push rod, the support block groove is in the shape of a column with a concave cross section, the distance between the opposite side walls of the support block groove matches the thickness of the support block, and the opposite side walls of the support block groove are in the shape of an outer convex plate on the axial projection of the support disk. Its function is to prevent the push rod from shaking through the setting of the push rod groove; to prevent the support block from rotating through the setting of the support block groove, so that the outer wall of the support block can maintain close contact with the inner wall of the air intake casing, thereby improving the effect of ensuring the roundness of the air intake casing.

[0009] Furthermore, the support plate is provided with a threaded hole connected to the push rod groove, the threaded hole and the push rod groove are arranged obliquely, the push rod is provided with a V-shaped groove, the positioning piece is a positioning bolt threadedly connected in the threaded hole, and when the push rod and the positioning piece are both located in the push rod groove, the bottom end of the positioning piece is located in the V-shaped groove. In the longitudinal section of the push rod, the V-shaped groove is V-shaped, the depth of the V-shaped groove is less than the radius of the push rod, and the side of the V-shaped groove adjacent to the spring is arranged parallel to the axial direction of the threaded hole. Its function is that, through the inclined design of the threaded hole and the push rod groove and the arrangement of the positioning piece and the V-shaped groove, it is possible to limit the distance that the push rod is ejected outward by the spring by only cutting off a small part of the material on the push rod, while ensuring the structural strength of the push rod, ensuring the service life of the push rod, and avoiding damage to the push rod caused by vibration generated during machining.

[0010] Furthermore, the pressure plate includes a rear pressure plate for pressing on the rear end surface of the rear flange of the air intake casing and a front pressure plate for pressing on the front end surface of the rear flange of the air intake casing, and the front pressure plate and the rear pressure plate are connected by clamping bolts. There are at least three clamping bolts evenly distributed in a ring around the axis of the pressure plate, and the inner diameter of the circle of the clamping bolt in the shape of the air intake casing is larger than the outer diameter of the rear flange of the air intake casing. The front pressure plate and the rear pressure plate are both provided with circular holes for the clamping bolts to pass through, and the clamping bolts are provided with matching nuts. Its function is that, through the combination of the front pressure plate, the rear pressure plate and the clamping bolts, the front pressure plate and the rear pressure plate can be respectively pressed on the front and rear surfaces of the rear flange of the air intake casing, so as to realize the deformation control of the rear flange of the air intake casing during the welding process, thereby avoiding the deformation of the rear flange of the air intake casing such as flanging during the welding process, and ensuring the size margin of machining after welding.

[0011] Furthermore, the outer edge of the rear pressure plate is evenly distributed with U-shaped grooves in an annular shape. When the rear pressure plate is assembled on the rear flange of the air intake casing, the U-shaped grooves correspond to the bolt holes of the rear flange of the air intake casing one by one, and the bolt holes of the rear flange of the air intake casing are completely located in the corresponding U-shaped grooves. When the U-shaped grooves correspond to the bolt holes of the rear flange of the air intake casing one by one, in the axial projection of the rear pressure plate, the distance between the U-shaped grooves and the bolt holes of the rear flange is greater than or equal to 5 mm. Its function is to provide space for welding the bolt holes of the rear flange through the setting of the U-shaped grooves.

[0012] Furthermore, the front pressure plate includes an upper pressure ring and a lower pressure ring connected by a locking bolt, and the upper pressure ring and the lower pressure ring are both semicircular arc-shaped. The front pressure plate is evenly distributed with ring-shaped clearance holes. When the front pressure plate is assembled on the rear flange of the air intake casing, the clearance holes correspond to the bolt holes of the rear flange of the air intake casing one by one, and the bolt holes of the rear flange of the air intake casing are completely located in the corresponding clearance holes. When the clearance holes correspond to the bolt holes of the rear flange of the air intake casing one by one, in the axial projection of the front pressure plate, the clearance holes are coaxially arranged with the bolt holes of the rear flange, and the diameter of the clearance holes is at least 4 mm larger than the diameter of the bolt holes of the rear flange. A matching nut is provided on the locking bolt. Its function is to prevent the front pressure plate from being partially melted during welding by setting the clearance holes, thereby avoiding contamination of the air intake casing.

[0013] Furthermore, the main shaft includes a connecting plate, a supporting section, a sleeve section, and a threaded section which are sequentially distributed from one end connected to the positioning plate to the other end connected to the pressure plate. The connecting plate and the positioning plate are connected by a plurality of axial bolts which are evenly distributed in a ring shape around the axis of the connecting plate. The supporting plate is provided with a mounting hole for being sleeved on the sleeve section. The outer diameter of the supporting section is larger than the outer diameter of the sleeve section. The inner diameter of the mounting hole is equal to the outer diameter of the sleeve section. The pressure plate is provided with a through hole matching the threaded section. The front and rear sides of the pressure plate are provided with locking nuts for being threadedly connected to the threaded section. The positioning plate, the supporting plate, and the pressure plate are arranged parallel to each other. The main shaft, the positioning plate, the supporting plate, and the pressure plate are all arranged coaxially. The main shaft and the air intake casing are arranged coaxially. Its function is to enable the positioning plate, the supporting plate, and the pressure plate to be connected into a whole through the arrangement of the main shaft structure.

[0014] Furthermore, the through hole is provided on the rear pressure plate, and the rear pressure plate is sleeved on the threaded section. Its function is that, through the provision of two locking nuts, the locking nut located at the front side of the rear pressure plate can press the support plate onto the end surface of the support section, and at the same time, the locking nut located at the rear side of the rear pressure plate can press the rear pressure plate onto the rear end surface of the rear flange of the intake casing.

[0015] In a second aspect, a method for welding and machining bolt holes of a rear flange of an APU air intake casing is provided, using the above-mentioned welding and machining tool for bolt holes of a rear flange of an APU air intake casing, and sequentially comprises the following steps: Step S1, cleaning the air intake casing; Step S2, performing fluorescence detection on the rear flange of the air intake casing and marking cracks; Step S3, opening a U-shaped groove at the crack, and polishing 5-10 mm near the area to be welded to give a metallic luster, the U-shaped groove is the area to be welded after the crack is removed; Step S4, the front flange of the air intake casing is fixedly connected to the positioning plate by a circle of axial bolts; Step S5, pressing the pressing plate onto the rear flange of the air intake casing; Step S6, welding the area to be welded; Step S7, heat-treating the tooling equipped with the air intake casing and slowly cooling it to room temperature; Step S8, fix the bottom chuck of the positioning plate on the claw of the vertical drilling machine, and machine and drill holes to restore the inner diameter of the rear flange bolt hole according to the theoretical size of the rear flange bolt hole from the central axis of the air intake casing; Step S9, disassembling the pressing plate, and fixing the bottom chuck of the positioning plate on the claws of a vertical or horizontal lathe, and machining and cutting to restore the surface flatness of the rear flange of the air intake casing; Step S10, separating the air intake casing from the positioning plate; Step S11, performing fluorescence detection on the welding position.

[0016] The following steps are also included: Step S4a, at the same time as step S4, the support plate enters into the air intake casing, and the cylindrical surfaces of all the support blocks on the support plate are in close contact with the inner wall of the air intake casing; Step S5a, during step S5, firstly, the through hole of the rear pressure plate is passed through the threaded section on the main shaft and attached to the rear end face of the rear flange of the air intake casing, then the locking nut is screwed into the threaded section, so that the locking nut presses the rear pressure plate, thereby pressing the rear end face of the rear flange of the air intake casing, then the upper pressure ring and the lower pressure ring connected to form the front pressure plate by the locking bolt are attached to the front end face of the rear flange of the air intake casing, the clamping bolt is passed through the front pressure plate and the rear pressure plate, and the nuts matched with the clamping bolt are used to press the rear flange of the air intake casing between the front pressure plate and the rear pressure plate; Step S6a: In step S6, the welding is performed by argon arc welding or laser welding. When argon arc welding is performed, an aluminum alloy welding wire with a diameter of 1.6 mm and an alternating current of 40 to 80 A are used for welding; Step S7a: In step S7, the heat treatment temperature is 155-160° C., the heat treatment time is 2 hours, and heat treatment may not be performed when the number of bolt holes on the rear flange of the welded air intake casing does not exceed 2; Step S12: If cracks are still found after the fluorescence detection, mark the cracks and start the loop operation from step S3.

[0017] The present invention has the beneficial effects: 1. The air intake casing can be fixed on the positioning plate by setting the positioning plate; the pressure plate can be pressed on the rear flange of the air intake casing to avoid the phenomenon of flanging of the rear flange of the air intake casing during welding; the support plate can support the inner wall of the air intake casing to ensure the roundness and processing rigidity of the air intake casing during machining; 2. Since vibration is easily generated during machining, if an integral rigid structure is used to support the inner wall of the air intake casing, the air intake casing is easily deformed, affecting the machining flatness of the rear flange plane of the air intake casing; by setting the positioning parts, the distance that the support parts extend outward can be limited, so that when the support parts are at the maximum outward distance, the circular contour surrounded by the outermost ends of all the support parts matches the inner wall of the air intake casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the three-dimensional structure of Example 1; Figure 2 This is a schematic diagram of the three-dimensional structure of Example 1 with an air intake casing installed; Figure 3 This is a front view of the structure of Example 1 with an air intake casing installed; Figure 4for Figure 3 Schematic diagram of the cross-sectional structure at AA in the middle; Figure 5 for Figure 4 A schematic diagram of the enlarged structure at B in the middle; Figure 6 Schematic diagram of the three-dimensional structure of the main shaft in Example 1; Figure 7 is a schematic diagram of the three-dimensional structure of the support block in Example 1; Figure 8 This is a schematic diagram of the three-dimensional structure of the top rod in Example 1.

[0019] : Illustrations: 1. positioning plate; 2. pressure plate; 201. rear pressure plate; 202. front pressure plate; 3. support plate; 301. support block groove; 302. push rod groove; 4. main shaft; 401. connecting plate; 402. support section; 403. sleeve section; 404. threaded section; 5. support member; 501. support block; 502. push rod; 6. spring; 7. positioning member; 8. threaded hole; 9. V-shaped groove; 10. U-shaped groove; 11. front flange; 12. rear flange; 13. clamping bolt; 14. bolt hole of rear flange; 15. upper pressure ring; 16. lower pressure ring; 17. locking bolt; 18. clearance hole; 19. mounting hole; 20. through hole; 21. locking nut. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0021] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. 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 direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0022] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Example 1 In the first aspect, a welding and machining tool for bolt holes of the rear flange of an APU air intake casing is provided, such as Figure 1 As shown, it includes a positioning plate 1 for detachably connecting with the front flange 11 of the air intake casing and a pressure plate 2 for pressing on the rear flange 12 of the air intake casing. A support plate 3 for supporting the inner wall of the air intake casing is provided between the positioning plate 1 and the pressure plate 2. The positioning plate 1, the support plate 3 and the pressure plate 2 are connected by a main shaft 4. The support plate 3 is arranged near the pressure plate 2. A chuck for being grasped by a claw on a machine tool is provided on the side of the positioning plate 1 facing away from the pressure plate 2. The chuck is coaxially arranged with the positioning plate 1. The outer diameter of the chuck is smaller than the outer diameter of the positioning plate 1. The positioning plate 1 is evenly hollowed out around the chuck to reduce the overall weight of the positioning plate 1. The positioning plate 1 is evenly provided with fastening bolt holes around the area where the weight-reducing holes are located. The fastening bolt holes correspond to the bolt holes on the front flange 11 of the air intake casing one by one. The front flange 11 of the air intake casing is fixed to the positioning plate 1 by a circle of axial bolts passing through the fastening bolt holes and the bolt holes of the front flange 11, so as to realize the detachable connection between the front flange 11 of the air intake casing and the positioning plate 1. All bolts are equipped with corresponding nuts, which is common knowledge and will not be elaborated. The main shaft 4 is coaxially arranged with the positioning plate 1, the support plate 3, and the pressure plate 2. Its function is that, through the setting of the positioning plate 1, the air intake casing can be fixed on the positioning plate 1; through the setting of the pressure plate 2, it can be pressed on the rear flange 12 of the air intake casing to avoid the phenomenon of flanging of the rear flange 12 of the air intake casing during welding; through the setting of the support plate 3, the inner wall of the air intake casing can be supported to ensure the roundness and processing rigidity of the air intake casing during machining.

[0024] Specifically, Figure 4 As shown, at least three support members 5 for contacting the inner wall of the air intake casing are arranged in a ring shape on the support plate 3, a spring 6 is arranged between the support member 5 and the support plate 3, and a positioning member 7 for fixing the position of the support member 5 is arranged on the support plate 3. Its function is that since vibration is easy to be generated during machining, if the inner wall of the air intake casing is supported by an integral rigid structure, the air intake casing is easy to be deformed, affecting the machining flatness of the plane of the rear flange 12 of the air intake casing; through the setting of the positioning member 7, the distance that the support member 5 extends outward can be limited, so that when the support member 5 is at the maximum distance of extending outward, the circular contour surrounded by the outermost ends of all the support members 5 matches the inner wall of the air intake casing.

[0025] Specifically, Figure 5As shown, the support member 5 includes a support block 501 for directly contacting the inner wall of the air intake casing and a push rod 502 connected to the support rod. The support plate 3 is provided with a push rod groove 302 for embedding the push rod 502 and a support block groove 301 for embedding the support block 501. The width of the push rod groove 302 is smaller than the width of the support block groove 301. The support block 501 and the push rod 502 are connected by a fixing pin that penetrates the push rod 502 and the support block 501 along the radial direction of the push rod 502. Figure 8 As shown, the top rod 502 is cylindrical. Figure 7 As shown, the support block 501 has a cylindrical surface whose curvature matches the inner wall of the air intake casing and a cylinder for embedding into the push rod 502. The fixing pin penetrates the cylinder and the push rod 502 to connect the support block 501 with the push rod 502. One end of the support block 501 of the push rod 502 is provided with a support surface for supporting the spring 6 embedded in the push rod 502. The outer diameter of the spring 6 matches the inner diameter of the push rod 502. The push rod groove 302 is in the shape of a cylindrical groove. The push rod groove 302 extends radially along the support plate 3. The inner diameter of the push rod groove 302 matches the outer diameter of the push rod 502. The support block groove 301 is in the shape of a column with a concave cross section. The distance between the opposite side walls of the support block groove 301 matches the thickness of the support block 501. Its function is to prevent the push rod 502 from shaking through the setting of the push rod groove 302; to prevent the support block 501 from rotating through the setting of the support block groove 301, so that the outer wall of the support block 501 can maintain close contact with the inner wall of the air intake casing, thereby improving the effect of ensuring the roundness of the air intake casing.

[0026] Specifically, Figure 5 As shown, the support plate 3 is provided with a threaded hole 8 connected to the push rod groove 302, the threaded hole 8 is inclined with the push rod groove 302, the push rod 502 is provided with a V-shaped groove 9, the positioning member 7 is a positioning bolt threadedly connected in the threaded hole 8, and when the push rod 502 and the positioning member 7 are both located in the push rod groove 302, the bottom end of the positioning member 7 is located in the V-shaped groove 9. In the longitudinal section of the push rod 502, the V-shaped groove 9 is V-shaped, the depth of the V-shaped groove 9 is less than the radius of the push rod 502, and the side of the V-shaped groove 9 adjacent to the spring 6 is arranged parallel to the axial direction of the threaded hole 8. Its function is that, through the inclined design of the threaded hole 8 and the ejector groove 302 and the arrangement of the positioning piece 7 and the V-shaped groove 9, only a small part of the material on the ejector 502 can be cut off to limit the distance that the ejector 502 is ejected outward by the spring 6, while ensuring the structural strength of the ejector 502 and the service life of the ejector 502, and avoiding damage to the ejector 502 caused by vibration generated during machining.

[0027] Specifically, Figure 4 , Figure 5As shown, the pressure plate 2 includes a rear pressure plate 201 for pressing on the rear end surface of the rear flange 12 of the air intake casing and a front pressure plate 202 for pressing on the front end surface of the rear flange 12 of the air intake casing, and the front pressure plate 202 is connected to the rear pressure plate 201 by clamping bolts. There are at least three clamping bolts evenly distributed in a ring around the axis of the pressure plate 2, and the inner diameter of the circle of the clamping bolt in the shape of the air intake casing is greater than the outer diameter of the rear flange 12 of the air intake casing. Both the front pressure plate 202 and the rear pressure plate 201 are provided with round holes for the clamping bolts to pass through, and the clamping bolts are provided with matching nuts. Its function is that, through the combined arrangement of the front pressure plate 202, the rear pressure plate 201 and the clamping bolts, the front pressure plate 202 and the rear pressure plate 201 can respectively clamp the front and rear surfaces of the intake casing rear flange 12, thereby realizing deformation control of the intake casing rear flange 12 during the welding process, thereby avoiding deformation such as flanging of the intake casing rear flange 12 during the welding process, and ensuring the dimensional margin of machining after welding.

[0028] Specifically, Figure 2 As shown, the outer edge of the rear pressure plate 201 is evenly distributed with U-shaped grooves 10 in an annular shape. When the rear pressure plate 201 is assembled on the rear flange 12 of the air intake casing, the U-shaped grooves 10 correspond to the bolt holes 14 of the rear flange of the air intake casing one by one, and the bolt holes 14 of the rear flange of the air intake casing are completely located in the corresponding U-shaped grooves 10. When the U-shaped grooves 10 correspond to the bolt holes 14 of the rear flange of the air intake casing one by one, in the axial projection of the rear pressure plate 201, the distance between the U-shaped grooves 10 and the bolt holes 14 of the rear flange is greater than or equal to 5 mm. Its function is to provide space for welding the bolt holes 14 of the rear flange through the arrangement of the U-shaped grooves 10.

[0029] Specifically, Figure 3 As shown, the front pressure plate 202 includes an upper pressure ring 15 and a lower pressure ring 16 connected by a locking bolt 17, and the upper pressure ring 15 and the lower pressure ring 16 are both semicircular arc-shaped. The front pressure plate 202 is evenly distributed with ring-shaped clearance holes 18. When the front pressure plate 202 is assembled on the rear flange 12 of the air intake casing, the clearance holes 18 correspond to the bolt holes 14 of the rear flange of the air intake casing one by one, and the bolt holes 14 of the rear flange of the air intake casing are completely located in the corresponding clearance holes 18. When the clearance holes 18 correspond to the bolt holes 14 of the rear flange of the air intake casing one by one, in the axial projection of the front pressure plate 202, the clearance holes 18 are coaxially arranged with the bolt holes 14 of the rear flange, and the diameter of the clearance holes 18 is at least 4 mm larger than the diameter of the bolt holes 14 of the rear flange. The locking bolt 17 is provided with a matching nut. Its function is to avoid partial melting of the front pressure plate 202 during welding through the setting of the clearance hole 18, thereby avoiding contamination of the air intake casing.

[0030] Specifically, Figure 6As shown, the spindle 4 includes a connecting disk 401, a supporting section 402, a sleeve section 403, and a threaded section 404 which are sequentially distributed from one end connected to the positioning disk 1 to the end connected to the pressure plate 2. The connecting disk 401 is connected to the positioning disk 1 by a plurality of axial bolts which are evenly distributed in a ring shape around the axis of the connecting disk 401. The supporting disk 3 is provided with a mounting hole 19 for sleeved on the sleeve section 403. The outer diameter of the supporting section 402 is greater than the outer diameter of the sleeve section 403. The inner diameter of the mounting hole 19 is equal to the outer diameter of the sleeve section 403. The pressure plate 2 is provided with a through hole 20 which matches the threaded section 404. The front and rear sides of the pressure plate 2 are provided with locking nuts 21 which are threadedly connected to the threaded section 404. The positioning disk 1, the supporting disk 3, and the pressure plate 2 are arranged parallel to each other. The spindle 4, the positioning disk 1, the supporting disk 3, and the pressure plate 2 are all arranged coaxially. The spindle 4 is arranged coaxially with the air intake casing. Its function is to connect the positioning plate, the supporting plate 3 and the pressing plate 2 into a whole through the structural setting of the main shaft 4.

[0031] Specifically, Figure 4 As shown, the through hole 20 is provided on the rear pressure plate 201, and the rear pressure plate 201 is sleeved on the threaded section 404. Its function is that, through the provision of two locking nuts 21, the locking nut 21 located at the front side of the rear pressure plate 201 can press the support plate 3 onto the end surface of the support section 402, and at the same time, the locking nut 21 located at the rear side of the rear pressure plate 201 can press the rear pressure plate 201 onto the rear end surface of the intake casing rear flange 12.

[0032] In a second aspect, a method for welding and machining bolt holes of a rear flange of an APU air intake casing is provided, using the above-mentioned welding and machining tool for bolt holes of a rear flange of an APU air intake casing, and sequentially comprises the following steps: Step S1, cleaning the air intake casing; Step S2, performing fluorescence detection on the rear flange 12 of the air intake casing and marking cracks; Step S3, opening a U-shaped groove at the crack, and polishing 5-10 mm near the area to be welded to give a metallic luster, the U-shaped groove is the area to be welded after the crack is removed; Step S4, the front flange 11 of the air intake casing is fixedly connected to the positioning plate 1 by a circle of axial bolts; Step S5, pressing the pressing plate 2 onto the rear flange 12 of the air intake casing; Step S6, welding the area to be welded; Step S7, heat-treating the tooling equipped with the air intake casing and slowly cooling it to room temperature; Step S8, fix the bottom chuck of the positioning plate 1 on the claw of the vertical drilling machine, and machine and drill the rear flange bolt hole 14 according to the theoretical size of the rear flange bolt hole 14 from the central axis of the air intake casing to restore the inner diameter of the rear flange bolt hole 14; Step S9, disassembling the pressing plate 2, and fixing the bottom chuck of the positioning plate 1 on the claws of a vertical or horizontal lathe, and machining and cutting to restore the surface flatness of the rear flange 12 of the air intake casing; Step S10, separating the air intake casing from the positioning plate 1; Step S11, performing fluorescence detection on the welding position.

[0033] The following steps are also included: Step S4a, at the same time as step S4, the support plate 3 enters into the air intake casing, and the cylindrical surfaces of all the support blocks 501 on the support plate 3 are in close contact with the inner wall of the air intake casing; Step S5a, during step S5, firstly, the through hole 20 of the rear pressure plate 201 is passed through the threaded section 404 on the main shaft 4 and affixed to the rear end surface of the rear flange 12 of the air intake casing, then the locking nut 21 is screwed into the threaded section 404, so that the locking nut 21 presses the rear pressure plate 201, thereby the rear pressure plate 201 presses the rear end surface of the rear flange 12 of the air intake casing, then the upper pressure ring 15 and the lower pressure ring 16 connected to the front pressure plate 202 by the locking bolts 17 are affixed to the front end surface of the rear flange 12 of the air intake casing, the clamping bolts are passed through the front pressure plate 202 and the rear pressure plate 201, and the nuts matched with the clamping bolts are used to press the rear flange 12 of the air intake casing between the front pressure plate 202 and the rear pressure plate 201; Step S6a: In step S6, the welding is performed by argon arc welding or laser welding. When argon arc welding is performed, an aluminum alloy welding wire with a diameter of 1.6 mm and an alternating current of 40 to 80 A are used for welding; Step S7a: In step S7, the heat treatment temperature is 155-160° C., the heat treatment time is 2 hours, and no heat treatment is required when the number of the welded intake casing rear flange bolt holes 14 does not exceed 2; Step S12: If cracks are still found after the fluorescence detection, mark the cracks and start the loop operation from step S3.

[0034] The working principle of this embodiment is described as follows: through the setting of the positioning plate 1, it can not only play the role of fixing the connection of the air intake casing, but also facilitate the installation of the entire tooling on the clamping claws of the machine tool; through the setting of the front pressure plate 202 and the rear pressure plate 201, it can avoid the rear flange 12 of the air intake casing from flanging and other deformations during the welding process, and it is convenient to dismantle after the welding is completed, which is beneficial to the processing of the surface of the rear flange 12 of the air intake casing; through the setting of the support plate 3 and the support members 5 and springs 6 in the support plate 3, it is possible to maintain the roundness of the air intake casing during welding and avoid the air intake casing from being deformed by heat, and it can also shrink inwards due to the vibration of the air intake casing during machining to avoid deformation of the air intake casing support.

[0035] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A welding and machining tool for bolt holes of the rear flange of an APU air intake casing, characterized in that: The invention comprises a positioning plate (1) for being detachably connected to a front flange (11) of an air intake casing and a pressure plate (2) for being pressed onto a rear flange (12) of the air intake casing. A support plate (3) for supporting the inner wall of the air intake casing is provided between the positioning plate (1) and the pressure plate (2). The positioning plate (1), the support plate (3) and the pressure plate (2) are connected via a main shaft (4).

2. The APU air intake casing rear flange bolt hole welding and machining tool according to claim 1, characterized in that: At least three support members (5) for contacting the inner wall of the air intake casing are arranged in a ring shape on the support plate (3), a spring (6) is provided between the support member (5) and the support plate (3), and a positioning member (7) for fixing the position of the support member (5) is provided on the support plate (3).

3. The APU air intake case rear flange bolt hole welding and machining tool according to claim 2, characterized in that: The support member (5) comprises a support block (501) for directly contacting the inner wall of the air intake casing and a push rod (502) connected to the support rod, and the support plate (3) is provided with a push rod groove (302) for embedding the push rod (502) and a support block groove (301) for embedding the support block (501), and the width of the push rod groove (302) is smaller than the width of the support block groove (301).

4. The APU air intake case rear flange bolt hole welding and machining tool according to claim 3, characterized in that: The support plate (3) is provided with a threaded hole (8) connected to the push rod groove (302), the threaded hole (8) and the push rod groove (302) are arranged obliquely, the push rod (502) is provided with a V-shaped groove (9), the positioning member (7) is a positioning bolt threadedly connected in the threaded hole (8), and when the push rod (502) and the positioning member (7) are both located in the push rod groove (302), the bottom end of the positioning member (7) is located in the V-shaped groove (9).

5. The APU air intake case rear flange bolt hole welding and machining tool according to claim 1, characterized in that: The pressure plate (2) comprises a rear pressure plate (201) for pressing on the rear end surface of the rear flange (12) of the air intake casing and a front pressure plate (202) for pressing on the front end surface of the rear flange (12) of the air intake casing, wherein the front pressure plate (202) and the rear pressure plate (201) are connected via a clamping bolt (13).

6. The APU air intake case rear flange bolt hole welding and machining tool according to claim 5, characterized in that: The outer edge of the rear pressure plate (201) is evenly distributed with U-shaped grooves (10) in an annular shape. When the rear pressure plate (201) is assembled on the intake casing rear flange (12), the U-shaped grooves (10) correspond to the intake casing rear flange bolt holes (14) one by one, and the intake casing rear flange bolt holes (14) are completely located in the corresponding U-shaped grooves (10).

7. The APU air intake case rear flange bolt hole welding and machining tool according to claim 5, characterized in that: The front pressure plate (202) comprises an upper pressure ring (15) and a lower pressure ring (16) connected by a locking bolt (17); the upper pressure ring (15) and the lower pressure ring (16) are both semicircular in shape; the front pressure plate (202) is provided with evenly distributed ring-shaped clearance holes (18); when the front pressure plate (202) is assembled on the rear flange (12) of the air intake casing, the clearance holes (18) correspond one-to-one with the bolt holes (14) of the rear flange of the air intake casing, and the bolt holes (14) of the rear flange of the air intake casing are completely located in the corresponding clearance holes (18).

8. The APU air intake case rear flange bolt hole welding and machining tool according to claim 5, characterized in that: The main shaft (4) comprises a connecting plate (401), a supporting section (402), a sleeve section (403), and a threaded section (404) which are sequentially arranged from one end connected to the positioning plate (1) to the other end connected to the pressing plate (2); the connecting plate (401) is connected to the positioning plate (1) via an axis bolt; the supporting plate (3) is provided with a mounting hole (19) for being sleeved on the sleeve section (403); the outer diameter of the supporting section (402) is greater than the outer diameter of the sleeve section (403); the inner diameter of the mounting hole (19) is equal to the outer diameter of the sleeve section (403); the pressing plate (2) is provided with a through hole (20) matching the threaded section (404); and locking nuts (21) for being threadedly connected to the threaded section (404) are provided on the front and rear sides of the pressing plate (2).

9. The APU air intake case rear flange bolt hole welding and machining tool according to claim 8, characterized in that: The through hole (20) is provided on the rear pressing plate (201), and the rear pressing plate (201) is sleeved on the threaded section (404).

10. A method for welding and machining bolt holes of the rear flange of an APU air intake casing, characterized in that: The use of the welding and machining tooling for the bolt hole (14) of the rear flange of an APU air intake casing as claimed in any one of claims 1 to 9 comprises the following steps in sequence: Step S1, cleaning the air intake casing; Step S2, performing fluorescence detection on the rear flange (12) of the air intake casing and marking cracks; Step S3, make a U-shaped groove at the crack, and polish 5-10 mm near the area to be welded to give it a metallic luster; Step S4, the front flange (11) of the air intake casing is fixedly connected to the positioning plate (1) by a circle of axial bolts; Step S5, pressing the pressing plate (2) onto the rear flange (12) of the air intake casing; Step S6, welding the area to be welded; Step S7, heat-treating the tooling equipped with the air intake casing and slowly cooling it to room temperature; Step S8, fix the bottom chuck of the positioning plate (1) on the jaws of the drilling machine, and machine and drill holes according to the theoretical size of the rear flange bolt hole (14) from the central axis of the air intake casing to restore the inner diameter of the rear flange bolt hole (14); Step S9, disassembling the pressing plate (2), fixing the bottom chuck of the positioning plate (1) on the claws of the lathe, and machining and cutting to restore the surface flatness of the rear flange (12) of the air intake casing; Step S10, separating the air intake casing from the positioning plate (1); Step S11, performing fluorescence detection on the welding position.

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