Welding fixture for brush seal structure and method of using same

Abstract

This invention provides a welding fixture and its method for using a brush-type sealing structure. The welding fixture includes a base, a pressure plate, a spring, and a screw. The base abuts against the side of the rear baffle opposite to the front baffle. The pressure plate abuts against the side of the front baffle opposite to the rear baffle. The pressure plate has a through hole and a countersunk hole; the through hole connects to the countersunk hole on the side opposite to the base. The spring is disposed within the countersunk hole. One end of the screw is threaded to the base, and the other end abuts against the spring, allowing the spring to extend and retract along the screw's axial direction. The welding fixture provided by this invention not only meets welding quality requirements and forms high-quality weld joints, but also significantly improves the flexibility and efficiency of the welding process.

Description

Technical Field

[0001] This invention relates to the field of welding fixture technology, and more specifically, to a welding fixture with a brush-type sealing structure and its method of use. Background Technology

[0002] As the aviation industry moves towards lightweighting, high speed, and high performance, the optimization and improvement of aero-engine performance is of paramount importance. Sealing devices are crucial components of aero-engines, ensuring the normal and effective operation of the mechanical system. Dozens of sealing devices are installed in the air passages and main bearing cavities of aero-engines, making them an indispensable part of guaranteeing engine performance. Compared to traditional labyrinth seals, contact-type moving brush seals offer superior performance and represent an advanced flexible sealing technology developed in recent years. They are of paramount importance for improving aero-engine performance (such as thrust-to-weight ratio, reliability, fuel efficiency, and service life).

[0003] In engines, gas leakage caused by interstage pressure differences significantly reduces engine efficiency. Reducing gas leakage has always been an important research topic for aero-engines. Brush seals are a new type of sealing structure that can significantly reduce gas leakage in the secondary flow path of an engine. They are the most effective replacement for toothed seals. Replacing toothed seals with brush seals in just one or a few critical areas of the engine can increase engine thrust by 1-3%, reduce fuel consumption by 3-5%, and improve engine surge margin.

[0004] Currently, electron beam welding is widely used for brush-type sealing structures. Although electron beam welding offers high quality, it is costly, requires a long vacuuming time, and has low efficiency, thus limiting the development of sealing structures. A brush-type sealing structure consists of three parts: a front baffle, a brush filament bundle, and a rear baffle. The brush filament bundle is composed of tightly packed, soft, and fine layers of brush filaments. The front baffle fixes and protects the brush filament bundle, while the rear baffle supports it, preventing large axial deformation under significant pressure differentials and maintaining stable sealing performance.

[0005] Existing brush seal structures are generally fastened to corresponding tooling with screws. When welding the brush seal structure, the welding heat input will cause the brush seal structure to expand due to heat. Under the action of expansion force, it is easy to push the tooling to move. After welding, the brush seal structure cools and shrinks, which affects the installation position accuracy and dimensional accuracy of the brush seal structure. In fact, under the action of thermal expansion force, the screw may even break, causing damage to the tooling. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem this invention aims to solve is that existing tooling cannot adapt to the thermal expansion and contraction during the welding of brush sealing structures, resulting in a decrease in the positional and dimensional accuracy of the brush sealing structures.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] In a first aspect, the present invention provides a welding fixture for welding a brush-type sealing structure. The brush-type sealing structure includes a front baffle, a brush filament bundle, and a rear baffle. The front baffle and the rear baffle are disposed opposite to each other and respectively abut against both sides of the brush filament bundle. The fixture includes a base, a pressure plate, a spring, and a screw. The base abuts against the side of the rear baffle opposite to the front baffle. The pressure plate abuts against the side of the front baffle opposite to the rear baffle. The pressure plate has a through hole and a countersunk hole. The side of the through hole opposite to the base is connected to the countersunk hole. The spring is disposed in the countersunk hole. One end of the screw is threadedly connected to the base, and the other end of the screw abuts against the spring, so that the spring can extend and retract along the axial direction of the screw.

[0011] Preferably, the base is provided with a boss, the length direction of which is parallel to the axial direction of the screw, and the pressure plate is provided with a groove that mates with the boss; or, the pressure plate is provided with a boss, the length direction of which is parallel to the axial direction of the screw, and the base is provided with a groove that mates with the boss.

[0012] Preferably, there is a predetermined distance between the end face of the boss and the bottom face of the groove.

[0013] Preferably, the front baffle is provided with a first through hole along the axial direction, the brush bristle bundle is provided with a second through hole along the axial direction, the rear baffle is provided with a third through hole along the axial direction, the pressure plate is provided with a first limiting part, the first limiting part abuts against the inner wall of the first through hole, the base is provided with a second limiting part and a third limiting part, the second limiting part abuts against the inner wall of the second through hole, and the third limiting part abuts against the inner wall of the third through hole.

[0014] Preferably, a plurality of through holes are evenly spaced along the circumference of the pressure plate.

[0015] Preferably, the base has a positioning hole, the axis of which is parallel to the axis of the screw.

[0016] Secondly, the present invention also provides a method for using the welding fixture of the brush sealing structure described in the above technical solution, characterized in that the method includes the following steps:

[0017] Step 1: Install the brush-type sealing structure onto the welding fixture, so that the base abuts against the side of the rear baffle away from the front baffle, the pressure plate abuts against the side of the front baffle away from the rear baffle, and position and fix the welding fixture on the worktable.

[0018] Step 2: Tighten the screw, which compresses the spring, and the spring applies a preset preload force to the pressure plate;

[0019] Step 3: Weld the interface to be welded on the brush-type sealing structure along the preset welding trajectory, so that the interface to be welded undergoes plastic deformation under the action of welding heat input, forming a plastic deformation zone. The plastic deformation zone is connected to form a weld under the action of the pre-tightening force.

[0020] (III) Beneficial Effects

[0021] The above-described technical solution of the present invention has at least the following advantages:

[0022] 1. One end of the spring abuts against the bottom of the countersunk hole, and the other end abuts against the screw nut. During welding of the brush seal structure, the thermal expansion of the brush seal structure pushes the pressure plate to move, causing the pressure plate to compress the spring, converting the kinetic energy of the pressure plate into the elastic potential energy of the spring. After welding, the brush seal structure cools and contracts. At this time, the spring releases its elastic potential energy, pushing the pressure plate to move and clamp the brush seal structure, thereby reducing the internal stress generated during welding and preventing large deformation of the brush seal structure under welding thermal stress, thus ensuring the positional and dimensional accuracy of the brush seal structure. Simultaneously, when the brush seal structure expands due to heat, the spring provides a buffer for the movement of the pressure plate, making the contact between the pressure plate and the screw nut a flexible contact, thus preventing the screw nut from breaking when the pressure plate moves. Compared with the welding fixtures in the prior art, the welding fixture provided by this invention not only meets the requirements of welding quality but also greatly improves the flexibility and efficiency of the welding process.

[0023] 2. During the welding of the brush sealing structure, the weld area on the brush sealing structure becomes a plastic deformation zone. The preload provided by the spring will press the front baffle, brush bundle and rear baffle together, making the contact between the three interfaces more compact. When the interface to be welded undergoes plastic deformation, the atomic diffusion at the interface to be welded is more complete under the upsetting force generated by the preload, thus forming a higher quality welded joint. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the welding fixture for the brush sealing structure provided in an embodiment of the present invention.

[0026] The labels for the attached figures are as follows:

[0027] 100. Brush-type sealing structure; 110. Front baffle; 120. Brush bristle bundle; 130. Rear baffle; 1. Base; 2. Pressure plate; 3. Spring; 4. Screw; 11. Boss; 12. Second limiting part; 13. Third limiting part; 14. Positioning hole; 21. Through hole; 22. Countersunk hole; 23. Groove; 24. First limiting part; 111. First through hole; 121. Second through hole; 131. Third through hole. Detailed Implementation

[0028] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0029] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0030] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments:

[0032] like Figure 1As shown, this embodiment of the invention provides a welding fixture for welding a brush-type sealing structure 100. The brush-type sealing structure includes a front baffle 110, a brush filament bundle 120, and a rear baffle 130. The front baffle 110 and the rear baffle 130 are arranged opposite to each other and respectively abut against both sides of the brush filament bundle 120. The welding fixture includes a base 1, a pressure plate 2, a spring 3, and a screw 4. The base 1 abuts against the side of the rear baffle 130 away from the front baffle 110. The pressure plate 2 abuts against the side of the front baffle 110 away from the rear baffle 130. The pressure plate 2 has a through hole 21 and a countersunk hole 22. The side of the through hole 21 away from the base 1 is connected to the countersunk hole 22. The spring 3 is disposed in the countersunk hole 22. One end of the screw 4 is threadedly connected to the base 1, and the other end of the screw 4 abuts against the spring 3 so that the spring 3 can extend and retract along the axial direction of the screw 4. Specifically, one end of spring 3 abuts against the bottom of countersunk hole 22, and the other end abuts against the nut of screw 4. During welding of the brush seal structure 100, the brush seal structure 100 expands due to heat, pushing the pressure plate 2 to move, causing the pressure plate 2 to compress spring 3, converting the kinetic energy of the pressure plate 2 into the elastic potential energy of spring 3. After welding, the brush seal structure 100 cools and contracts. At this time, spring 3 releases its elastic potential energy, pushing the pressure plate 2 to move and clamp the brush seal structure 100, thus avoiding large deformation of the brush seal structure 100 under welding thermal stress, thereby ensuring the positional and dimensional accuracy of the brush seal structure 100. At the same time, when the brush seal structure 100 expands due to heat, spring 3 can provide a buffer for the movement of pressure plate 2, making the contact between pressure plate 2 and the nut of screw 4 a flexible contact, thereby preventing the pressure plate 2 from breaking the nut of screw 4 when it moves.

[0033] In one embodiment, the base 1 has a boss 11, the length direction of which is parallel to the axial direction of the screw 4, and the pressure plate 2 has a groove 23 that mates with the boss 11. In another embodiment, the pressure plate 2 has a boss, the length direction of which is parallel to the axial direction of the screw 4, and the base 1 has a groove that mates with the boss. Since the length direction of the boss 11 is parallel to the axial direction of the screw 4, and the boss 11 is connected to the groove 23, the groove 23 restricts the movement of the boss 11, so that the boss 11 can only move along the axial direction of the screw 4. That is, the boss 11 and the groove 23 form a guide structure, so that the pressure plate 2 can only move along the axial direction of the screw 4, thereby avoiding radial movement of the pressure plate 2 and changing the positional accuracy of the brush sealing structure 100.

[0034] In one embodiment, a predetermined distance is spaced between the end face of the boss 11 and the bottom surface of the groove 23. The space formed between the end face of the boss 11 and the bottom surface of the groove 23 allows the pressure plate 2 to move, so that it can adapt to the displacement generated by the brush-type sealing structure 100 when it is heated and expanded.

[0035] In one embodiment, the front baffle 110 has a first through hole 111 along the axial direction, the brush filament bundle 120 has a second through hole 121 along the axial direction, the rear baffle 130 has a third through hole 131 along the axial direction, the pressure plate 2 has a first limiting part 24, which abuts against the inner wall of the first through hole 111, and the base 1 has a second limiting part 12 and a third limiting part 13, whereby the second limiting part 12 abuts against the inner wall of the second through hole 121 and the third limiting part 13 abuts against the inner wall of the third through hole 131. Through the cooperation of the above structures, radial movement of the front baffle 110, the brush filament bundle 120, and the rear baffle 130 can be restricted to ensure the positional accuracy of the brush-type sealing structure 100.

[0036] In one embodiment, a plurality of through holes 21 are evenly spaced along the circumference of the pressure plate 2. Each through hole 21 is fitted with a screw 4, and the plurality of screws 4 connect the base 1 and the pressure plate 2.

[0037] In one embodiment, the base 1 has a positioning hole 14, the axis of which is parallel to the axis of the screw 4. The positioning hole 14 is used to connect with a corresponding structure on the workbench to position the welding fixture, so as to facilitate the establishment of a welding trajectory coordinate system based on the positioning point during subsequent welding.

[0038] Secondly, the present invention also provides a method for using the welding fixture of the brush-type sealing structure in the above-mentioned technical solution, characterized in that the method includes the following steps:

[0039] Step 1: Install the brush-type sealing structure 100 onto the welding fixture so that the base 1 abuts against the side of the rear baffle 130 away from the front baffle 110, and the pressure plate 2 abuts against the side of the front baffle 110 away from the rear baffle 130. Then, position and fix the welding fixture on the worktable.

[0040] Step 2: Tighten screw 4. Screw 4 compresses spring 3, and spring 3 applies a preset preload force to pressure plate 2. Specifically, according to the torque required for welding, use a torque wrench to evenly tighten each screw 4 to ensure that the welding fixture is subjected to uniform force.

[0041] Step 3: Weld the interface to be welded on the brush sealing structure 100 along the preset welding trajectory, so that the interface to be welded undergoes plastic deformation under the action of welding heat input, forming a plastic deformation zone. The plastic deformation zone is connected under the action of pre-tightening force to form a weld. Specifically, during the welding of the brush sealing structure 100, the weld area on the brush sealing structure 100 becomes a plastic deformation zone. The pre-tightening force provided by the spring 3 will press the front baffle 110, the brush bundle 120 and the rear baffle 130, making the interface to be welded between the three more closely contacted. When the interface to be welded undergoes plastic deformation, under the action of the upsetting force generated by the pre-tightening force, the atomic diffusion at the interface to be welded is more complete, thereby forming a higher quality welded joint.

[0042] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A welding fixture for welding a brush-type sealing structure, the brush-type sealing structure comprising a front baffle, a brush filament bundle, and a rear baffle, wherein the front baffle and the rear baffle are disposed opposite to each other and respectively abut against both sides of the brush filament bundle, characterized in that, include: The base abuts against the side of the rear baffle that is away from the front baffle; A pressure plate abuts against the front baffle on the side opposite to the rear baffle. The pressure plate has a through hole and a countersunk hole. The side of the through hole opposite to the base is connected to the countersunk hole. A spring is disposed within the countersunk hole; A screw, one end of which is threaded to the base, and the other end of which abuts against the spring so that the spring can extend and retract along the axial direction of the screw.

2. The welding fixture for the brush-type sealing structure as described in claim 1, characterized in that, The base is provided with a boss, the length direction of which is parallel to the axial direction of the screw, and the pressure plate is provided with a groove that mates with the boss. Alternatively, the pressure plate may have a boss, the length of which is parallel to the axial direction of the screw, and the base may have a groove that mates with the boss.

3. The welding fixture for the brush-type sealing structure as described in claim 2, characterized in that, There is a predetermined distance between the end face of the boss and the bottom face of the groove.

4. The welding fixture for the brush-type sealing structure as described in claim 1, characterized in that, The front baffle is provided with a first through hole along the axial direction, the brush bristle bundle is provided with a second through hole along the axial direction, the rear baffle is provided with a third through hole along the axial direction, the pressure plate is provided with a first limiting part, the first limiting part abuts against the inner wall of the first through hole, the base is provided with a second limiting part and a third limiting part, the second limiting part abuts against the inner wall of the second through hole, and the third limiting part abuts against the inner wall of the third through hole.

5. The welding fixture for the brush-type sealing structure as described in claim 1, characterized in that, Multiple through holes are evenly spaced along the circumference of the pressure plate.

6. The welding fixture for the brush-type sealing structure as described in claim 1, characterized in that, The base has a positioning hole, and the axis of the positioning hole is parallel to the axis of the screw.

7. A method of using a welding fixture for a brush-type sealing structure as described in any one of claims 1-6, characterized in that, The method of use includes the following steps: Step 1: Install the brush-type sealing structure onto the welding fixture, so that the base abuts against the side of the rear baffle away from the front baffle, the pressure plate abuts against the side of the front baffle away from the rear baffle, and position and fix the welding fixture on the worktable. Step 2: Tighten the screw, which compresses the spring, and the spring applies a preset preload force to the pressure plate; Step 3: Weld the interface to be welded on the brush-type sealing structure along the preset welding trajectory, so that the interface to be welded undergoes plastic deformation under the action of welding heat input, forming a plastic deformation zone. The plastic deformation zone is connected to form a weld under the action of the pre-tightening force.

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