Laser welding fixture and laser welding method for aircraft engine air duct inner tube assembly

Abstract

The present invention relates to a laser welding fixture and a laser welding method for an inner tube assembly of an aircraft engine air duct, which belongs to the field of mechanical processing technology, and includes a core shaft, a gland, a first clamp and a second clamp; the core shaft is a cylindrical structure, one end of the core shaft is connected to the gland, and the other end is provided with a flange, the heat shield sleeve is connected to the core shaft surface, and its two ends are connected between the flange and the gland and limited by the first clamp, and a plurality of damping rings are limited to the surface of the heat shield cylinder by the second clamp. The present invention ensures the precise fit between the damping ring and the heat shield through a laser welding fixture, and the precisely positioned damping ring can more effectively control the thermal deformation and cracks during the welding process, which helps to improve the stability and durability of the overall structure, provide a guarantee for the welding method, reduce the error during the welding process, improve the welding efficiency, and meet the production and use requirements.

Description

Technical Field

[0001] The invention relates to a laser welding fixture and a laser welding method, in particular to a laser welding fixture and a laser welding method for an inner tube assembly of an aero-engine air duct, and belongs to the technical field of mechanical processing. Background Art

[0002] The air duct inner tube assembly is welded by a heat shield and a damping ring. As an important component of the aircraft engine turbine component, it constitutes a part of the double-layer air duct of the turbine component. It belongs to the rotor part and plays a vital role in the cooling process of the turbine component. The heat shield is a thin-walled long cylindrical structure with an axial opening. Compared with conventional cylindrical parts, the structure is more complex; the opening size of the heat shield cylinder in the free state is 15 to 50 mm, and the cross-section is circular in the clamped state. The damping rings are equidistantly distributed on the outer surface of the heat shield cylinder along the axial direction. The cross-section of the damping ring is arched and maintains a certain angle relationship with the axial opening. The edge is welded to the heat shield cylinder by laser welding.

[0003] The thickness of the damping ring is 0.5mm, the thickness of the heat shield cylinder is 0.5mm, and the overall size of the air duct inner tube assembly is φ120×480. Laser welding of large-sized thin-walled parts is very easy to cause deformation. When assembling this part, it is necessary to ensure that the cylinder of the part is flat and the outer circle of the damping ring is in full contact with the inner wall of the air duct.

[0004] The Chinese utility model patent with the authorization announcement number CN216264364U discloses an aircraft engine duct welding fixture, which includes a first clamp body and a second clamp body that are relatively arranged and have the same structure, a balancing assembly is connected between the first clamp body and the second clamp body, and a welding gun bracket is abutted on the outer side of the balancing assembly. This welding fixture can solve the problem of circumferential or axial deformation of the two ducts due to heat, but is not suitable for welding the heat shield cylinder and the damping ring. The Chinese invention patent application with the publication number CN116748621A discloses a vacuum brazing method for the inner wall of the air duct and the damping ring, which discloses a welding method for the damping ring and the air duct, but it does not disclose the corresponding welding fixture, and cannot avoid the problem that the damping ring may be displaced during welding, and cannot meet the welding requirements.

[0005] Therefore, a novel welding fixture is urgently needed to overcome the above problems. Summary of the invention

[0006] In order to overcome the deficiencies in the prior art, the present invention provides a laser welding fixture and a laser welding method for an aircraft engine air duct inner tube assembly. During the entire welding process, the positioning is accurate, the welding deformation is small, and the welding efficiency is improved.

[0007] To achieve the above-mentioned purpose, the present invention discloses a laser welding fixture for an aircraft engine air duct inner tube assembly, wherein the air duct inner tube assembly is welded by a heat insulation cover and a damping ring, and comprises a core shaft, a pressure cover, a first clamp and a second clamp; the core shaft is a cylindrical structure, one end of the core shaft is connected to the pressure cover, and the other end is provided with a flange, the heat insulation cover is sleeved and connected to the surface of the core shaft, and the two ends of the heat insulation cover are connected between the flange and the pressure cover and are limited by the first clamp, and a plurality of damping rings are limited on the surface of the heat insulation cover cylinder by the second clamp.

[0008] Furthermore, an annular protrusion is provided at the connection between the core shaft surface and the end face of the heat insulation cover, a connecting plate is provided at the connecting end of the core shaft and the gland, a connecting rod is provided on the connecting plate, and the gland is connected to the core shaft through the connecting rod.

[0009] Furthermore, the first clamp and the second clamp are of semicircular arc structure and are used in pairs; the inner wall of the first clamp is provided with a groove that fits the end surface of the heat insulation cover, and the inner wall of the second clamp is provided with a convex groove that matches the outer circular surface of the damping ring.

[0010] Furthermore, connecting ears are extended from the ends of the first clamp and the second clamp.

[0011] Furthermore, it also includes a soft clamp and a block. The soft clamp is a circular locking piece with a limited through hole on its surface. The block can fit with the surface of the heat insulation cover cylinder. The soft clamp and the block are used together to angularly position the damping ring on the surface of the heat insulation cover.

[0012] Furthermore, it also includes a pressure ring; the pressure ring is a semicircular arc structure, and is used in groups of two to axially position the damping ring on the surface of the heat shield.

[0013] The laser welding method based on the laser welding fixture for the inner tube assembly of the aircraft engine air duct comprises the following steps:

[0014] Step S1, fitting parts: fitting the heat insulation cover onto the mandrel, with one end of the heat insulation cover attached to the annular protrusion of the mandrel, and tightening the surface of the heat insulation cover by using a plurality of sets of pressure rings to make it fully contact with the mandrel;

[0015] Step S2, positioning the heat insulation cover: adjusting the ends of the heat insulation cover to make them flush, tightening the heat insulation cover as a whole by setting multiple groups of soft clamps, embedding the gland into the heat insulation cover, close to the other end of the heat insulation cover, connecting the nut on the connecting rod to achieve the connection between the mandrel and the gland, using the first clamp to tighten the two ends of the heat insulation cover, and tightening the connecting ears on each group of the first clamps with bolts, and tightening the nuts to complete the overall positioning of the heat insulation cover;

[0016] Step S3, assembling the damping ring: loosen a section of the soft clamp and the pressure ring, calculate the axial distribution position of the damping ring, adjust the pressure ring to the damping ring assembly position and clamp it, locate the axial position of the damping ring through the side of the pressure ring, and put the soft clamp on the damping ring, place the block in the limiting through hole on the surface of the soft clamp, one end of the block is pressed against the axial opening of the heat insulation cover, and the other end is pressed against the end face of the damping ring, and the angular position of the damping ring is located by the block to complete the determination of the damping ring position, and perform positioning welding, then remove the soft clamp, use the second clamp to fix the damping ring, and use bolts to tighten the connecting ears. At this point, one group of damping rings is assembled, and the remaining damping rings are cyclically operated in this way to complete the assembly of all damping rings;

[0017] Step S4, clamping the tooling: the assembled tooling and the parts are clamped using a chuck on the welding equipment, and the welding equipment can control the longitudinal, transverse and vertical movement of the tooling, and can control its rotation around the rotary axis, as well as the overall movement around the X axis;

[0018] Step S5, welding programming: adjust the rotary axis of the part to be collinear with the Y axis, adjust the laser output head to determine the coordinate origin, and adjust the welding parameters as planned; refer to the planned weld position, start trajectory programming, all trajectory movements are achieved by keeping the laser output head stationary and moving the part, the movement of the laser output head only adjusts the incident angle of the laser on the part, the welding process is carried out in a circle-by-circle order, and the circles are welded one circle at a time;

[0019] Step S6, laser welding of parts: after programming is completed, the laser output head is adjusted to the program starting point, and the laser welding of parts is started after testing that the shielding gas is normally supplied. The welding process is monitored by the CCD imaging system on the equipment;

[0020] Step S7, take out the parts: After welding is completed, wait for the parts to cool down for 1 minute, remove the tooling and parts from the equipment, first remove the second clamp in the middle, then remove the first clamps at both ends, and finally remove the nuts and glands to take out the parts.

[0021] Furthermore, in step S5, the welding parameters include: defocus amount +lOmm, laser peak power 370W~400W, welding speed 6mm / s, shielding gas flow rate 15L / min, and in the adjustment of the laser timing, each weld starts with a power rise section of 0.1s and a power attenuation section of 0.2s.

[0022] Beneficial effects: The present invention provides a groove matching the end of the heat insulation cover on the inner wall of the first clamp, so as to achieve precise connection between the heat insulation cover and the clamp; and provides a convex groove matching the outer cylindrical surface of the damping ring on the inner wall of the second clamp, so as to limit the damping ring; through the laser welding clamp, the precise fit between the damping ring and the heat insulation cover is ensured, and the precise positioning of the damping ring can effectively control the thermal deformation during welding and reduce the generation of welding cracks; during the welding process, the positions of all damping rings are restricted, and the restriction is completed by only one overall clamping, which can effectively avoid the influence of the secondary clamping on the relative position of the damping ring, help to improve the position accuracy of the damping ring after welding, enhance the stability and durability of the overall structure of the air duct inner tube assembly, provide guarantee for the welding method, reduce errors in the welding process, and the formulated welding sequence and welding parameters can effectively reduce the post-welding deformation of the air duct inner tube assembly, such as overall bamboo deformation and wave deformation, while ensuring welding efficiency, so as to meet the production and use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The structure of the present invention is schematically shown Figure 1 ;

[0024] Figure 2 The structure of the present invention is schematically shown Figure 2 ;

[0025] Figure 3 for Figure 1 A schematic diagram of the enlarged structure of part A;

[0026] Figure 4 It is a structural schematic diagram of the inner tube assembly of the air duct of the present invention;

[0027] Figure 5 It is a structural schematic diagram of the mandrel of the present invention;

[0028] Figure 6 It is a structural schematic diagram of the gland of the present invention;

[0029] Figure 7 It is a schematic structural diagram of the first clamp of the present invention;

[0030] Figure 8 It is a schematic structural diagram of the second clamp of the present invention;

[0031] Fig. 9 It is a structural schematic diagram of the soft clamp of the present invention;

[0032] Fig.10 It is a structural schematic diagram of the mold block of the present invention;

[0033] Fig.11 It is a schematic structural diagram of the pressure ring of the present invention.

[0034] In the figure, 1, heat insulation cover; 2, damping ring; 3, core shaft; 4, pressure cover; 5, first clamp; 6, second clamp; 7, flange; 8, connecting plate; 9, connecting rod; 10, groove; 11, convex groove; 12, connecting ear; 13, soft clamp; 14, block; 15, limiting through hole; 16, pressure ring; 17, annular protrusion. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1 To Attachment Fig.11 The principles and features of the present invention are described, and the examples given are only used to explain the present invention, rather than to limit the scope of the present invention.

[0036] A laser welding fixture is used for an aircraft engine air duct inner tube assembly, the air duct inner tube assembly is welded by a heat insulation cover 1 and a damping ring 2, including a core shaft 3, a pressure cover 4, a first clamp 5 and a second clamp 6; the core shaft 3 is a cylindrical structure, one end of the core shaft 3 is connected to the pressure cover 4, and the other end is provided with a flange 7, the heat insulation cover 1 is sleeved and connected to the surface of the core shaft 3, and its two ends are connected between the flange 7 and the pressure cover 4 and are limited by the first clamp 5 to achieve locking of the end of the heat insulation cover 1, and a plurality of damping rings 2 are limited on the surface of the cylinder of the heat insulation cover 1 by the second clamp 6.

[0037] An annular protrusion 17 is provided at the connection between the surface of the core shaft 3 and the end face of the heat insulation cover 1, and a connecting plate 8 is provided at the connecting end of the core shaft 3 and the pressure cover 4. A connecting rod 9 is provided on the connecting plate 8, and the pressure cover 4 is connected to the core shaft 3 through the connecting rod 9.

[0038] The first clamp 5 and the second clamp 6 are of semicircular arc structure and are used in pairs. The inner wall of the first clamp 5 is provided with a groove 10 that fits the end surface of the heat insulation cover 1 and is used to press the end of the heat insulation cover 1. The inner wall of the second clamp 6 is provided with a convex groove 11 that matches the outer cylindrical surface of the damping ring 2, which can achieve compression of the to-be-welded part under the premise of avoiding deformation of the outer cylindrical surface of the damping ring 2. The width of the free edge to be welded is 2 mm.

[0039] Connecting ears 12 are extended from the ends of the first clamp 5 and the second clamp 6. After assembly, the connecting ears 12 are locked with bolts and nuts.

[0040] It also includes a soft clamp 13 and a block 14. The soft clamp 13 is a circular locking piece with a limited through hole 15 on its surface. The block 14 can fit with the surface of the cylinder of the heat insulation cover 1. The soft clamp 13 and the block 14 are used together to angularly position the damping ring 2 on the surface of the heat insulation cover 1.

[0041] The pressure ring 16 is a semicircular arc structure, and is used in pairs to axially position the damping ring 2 on the surface of the heat shield 1. The ends of the two pressure rings 16 are connected by a concave and convex block, and then locked with a connecting bolt nut.

[0042] The laser welding method based on the laser welding fixture for the inner tube assembly of the aircraft engine air duct comprises the following steps:

[0043] Step S1, fitting parts: fitting the heat shield 1 onto the mandrel 3, with one end of the heat shield 1 attached to the annular protrusion 17 of the mandrel 3, and tightening the surface of the heat shield 1 by using a plurality of sets of pressure rings 16 to make it fully contact with the mandrel 3;

[0044] Step S2, positioning the heat shield 1: adjusting the ends of the heat shield 1 to make them flush, tightening the heat shield 1 as a whole by setting multiple groups of soft clamps 13, embedding the gland 4 into the heat shield 1, close to the other end of the heat shield 1, connecting the nut on the connecting rod 9 to achieve the connection between the core shaft 3 and the gland 4, using the first clamp 5 to tighten the two ends of the heat shield 1, and tightening the connecting ears 12 on each group of the first clamp 5 with bolts, and tightening the nuts to complete the overall positioning of the heat shield 1;

[0045] Step S3, assembling the damping ring 2: loosen a section of the soft clamp 13 and the pressure ring 16, calculate the axial distribution position of the damping ring 2, adjust the pressure ring 16 to the assembly position of the damping ring 2 and clamp it, locate the axial position of the damping ring 2 through the side of the pressure ring 16, and put the soft clamp 13 on the damping ring 2, place the block 14 in the limiting through hole 15 on the surface of the soft clamp 13, one end of the block 14 is pressed against the axial opening of the heat insulation cover 1, and the other end is pressed against the end face of the damping ring 2, and the angular position of the damping ring 2 is located by the block 14, the position of the damping ring 2 is determined, and positioning welding is performed, and then the soft clamp 13 is removed, and the damping ring 2 is fixed with the second clamp 6, and the connecting ear 12 is tightened with bolts and nuts. At this point, one group of damping rings 2 is assembled, and the remaining damping rings 2 are cyclically operated in this way to complete the assembly of all damping rings 2;

[0046] Step S4, clamping the tooling: the assembled tooling and the parts are clamped using a chuck on the welding equipment, and the welding equipment can control the longitudinal, transverse and vertical movement of the tooling, and can control its rotation around the rotary axis, as well as the overall movement around the X axis;

[0047] Step S5, welding programming: adjust the rotary axis of the part to be collinear with the Y axis, adjust the laser output head to determine the coordinate origin, and adjust the welding parameters as scheduled, wherein the welding parameters include: defocus amount +10mm, laser peak power 390W, welding speed 6mm / s, shielding gas flow 15L / min, and in the adjustment of the laser timing, each weld starts with a power rise section of 0.1s and a power decay section of 0.2s;

[0048] According to the predetermined weld position, trajectory programming begins. All trajectory movements are achieved by keeping the laser head stationary and moving the parts. The movement of the laser head only adjusts the incident angle of the laser on the parts. The welding process is carried out in a circle-by-circle order, with each circle welded one circle at a time. Adjacent circles are arranged in an N-shaped pattern to complete the welding of all welds. A single-section weld is an intermittent weld of three sections, which is welded in the order of the step-by-step welding method. After simulation calculation, the formulated welding sequence and welding parameters can effectively reduce the post-welding deformation of the components, such as overall bamboo deformation and wave deformation, while ensuring welding efficiency.

[0049] Step S6, laser welding of parts: after programming is completed, the laser output head is adjusted to the program starting point, and the laser welding of parts is started after testing that the shielding gas is normally supplied. The welding process is monitored by the CCD imaging system on the equipment;

[0050] Step S7, take out the parts: After welding is completed, wait for the parts to cool down for 1 minute, remove the tooling and parts from the equipment, first remove the second clamp 6 in the middle, then remove the first clamp 5 at both ends, and finally remove the nut and gland 4 to take out the parts.

[0051] The present invention ensures the precise fit between the damping ring 2 and the heat shield 1 through a laser welding fixture, and the precise positioning of the damping ring 2 can effectively control the thermal deformation during welding and reduce the generation of welding cracks; during the welding process, the positions of all the damping rings 2 are restricted, and the limiting is completed by only one overall clamping, which can effectively avoid the influence of the secondary clamping on the relative position of the damping ring 2, help to improve the position accuracy of the damping ring 2 after welding, enhance the stability and durability of the overall structure of the air duct inner tube assembly, provide a guarantee for the welding method, and reduce errors during the welding process.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser welding fixture for an inner tube assembly of an aircraft engine air duct, wherein the inner tube assembly of the air duct is composed of a heat shield (1) and a damping ring (2) welded together, and characterized in that: The invention comprises a core shaft (3), a gland (4), a first clamp (5) and a second clamp (6); the core shaft (3) is a columnar structure, one end of the core shaft (3) is connected to the gland (4), and the other end thereof is provided with a flange (7); the heat shield (1) is sleeved and connected to the surface of the core shaft (3), and its two ends are connected between the flange (7) and the gland (4) and are limited by the first clamp (5); a plurality of damping rings (2) are limited on the surface of the cylinder of the heat shield (1) by the second clamp (6); the first clamp (5) and the second clamp (6) are semicircular arc structures, and are used in pairs; the inner wall of the first clamp (5) is provided with a groove (10) that fits the end surface of the heat shield (1), and the inner wall of the second clamp (6) is provided with a convex groove (11) that matches the outer cylindrical surface of the damping ring (2).

2. The laser welding fixture for the inner tube assembly of the aircraft engine air duct according to claim 1 is characterized in that: An annular protrusion (17) is provided at the connection between the surface of the core shaft (3) and the end surface of the heat insulation cover (1), a connecting plate (8) is provided at the connecting end between the core shaft (3) and the gland (4), a connecting rod (9) is provided on the connecting plate (8), and the gland (4) is connected to the core shaft (3) via the connecting rod (9).

3. The laser welding fixture for the inner tube assembly of the aircraft engine air duct according to claim 2 is characterized in that: Connecting ears (12) are extended from the ends of the first clamp (5) and the second clamp (6).

4. The laser welding fixture for the inner tube assembly of the aircraft engine air duct according to claim 3 is characterized in that: It also includes a soft clamp (13) and a mold block (14). The soft clamp (13) is a circular locking piece, and a limited position through hole (15) is provided on its surface. The mold block (14) can be fitted with the surface of the cylinder of the heat insulation cover (1). The soft clamp (13) and the mold block (14) are used in combination to angularly position the damping ring (2) on the surface of the heat insulation cover (1).

5. The laser welding fixture for the inner tube assembly of the aircraft engine air duct according to claim 4, characterized in that: It also includes a pressure ring (16); the pressure ring (16) is a semicircular arc structure, and is used in groups of two to axially position the damping ring (2) on the surface of the heat insulation cover (1).

6. A laser welding method based on the laser welding fixture for the inner tube assembly of the aircraft engine air duct according to claim 5, characterized in that: The following steps are involved: Step S1, fitting parts: fitting the heat shield (1) onto the mandrel (3), with one end of the heat shield (1) attached to the annular protrusion (17) of the mandrel (3), and tightening the surface of the heat shield (1) by using a plurality of sets of pressure rings (16) so that the heat shield (1) is in full contact with the mandrel (3); Step S2, positioning the heat shield (1): adjusting the ends of the heat shield (1) so that the ends are flush, tightening the heat shield (1) as a whole by setting a plurality of sets of soft clamps (13), embedding the gland (4) into the heat shield (1) close to the other end of the heat shield (1), connecting the nut on the connecting rod (9) to achieve the connection between the core shaft (3) and the gland (4), using the first clamp (5) to tighten the two ends of the heat shield (1), and tightening the connecting ears (12) on each set of the first clamp (5) with bolts, and tightening the nuts to complete the overall positioning of the heat shield (1); Step S3, assembling the damping ring (2): loosen a section of the soft clamp (13) and the pressure ring (16), calculate the axial distribution position of the damping ring (2), adjust the pressure ring (16) to the assembly position of the damping ring (2) and clamp it, locate the axial position of the damping ring (2) through the side of the pressure ring (16), and put the soft clamp (13) on the damping ring (2), place the mold block (14) in the limiting through hole (15) on the surface of the soft clamp (13), and press one end of the mold block (14) against the heat insulation cover (1 ) is axially opened, and the other end is closely attached to the end face of the damping ring (2), and the angular position of the damping ring (2) is positioned by the block (14), the position of the damping ring (2) is determined, and positioning welding is performed, and then the soft clamp (13) is removed, and the damping ring (2) is fixed by the second clamp (6), and the connecting ear (12) is tightened by bolts. At this point, one set of damping rings (2) is assembled, and the remaining damping rings (2) are cyclically operated in this manner to complete the assembly of all damping rings (2); Step S4, clamping the tooling: the assembled tooling and the parts are clamped using a chuck on the welding equipment, and the welding equipment can control the longitudinal, transverse and vertical movement of the tooling, and can control its rotation around the rotary axis, as well as the overall movement around the X axis; Step S5, welding programming: adjust the rotary axis of the part to be collinear with the Y axis, adjust the laser output head to determine the coordinate origin, and adjust the welding parameters as planned; refer to the planned weld position, start trajectory programming, all trajectory movements are achieved by keeping the laser output head stationary and moving the part, the movement of the laser output head only adjusts the incident angle of the laser on the part, the welding process is carried out in a circle-by-circle order, and the circles are welded one circle at a time; Step S6, laser welding of parts: after programming is completed, the laser output head is adjusted to the program starting point, and the laser welding of parts is started after testing that the shielding gas is normally supplied. The welding process is monitored by the CCD imaging system on the equipment; Step S7, removing parts: After welding is completed, wait for the parts to cool down for 1 minute, remove the tooling and parts from the equipment, first remove the second clamp (6) in the middle, then remove the first clamps (5) at both ends, and finally remove the nuts and glands (4) to remove the parts.

7. The laser welding method according to claim 6, characterized in that: In step S5, the welding parameters include: defocus amount +10mm, laser peak power 370W~400W, welding speed 6mm / s, shielding gas flow rate 15L / min. In the adjustment of laser timing, each weld starts with a power rise section of 0.1s and a power attenuation section of 0.2s.

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