Fixture for welding inner and outer expansion sleeves on main bracket

Abstract

The invention discloses a main support welding inner and outer expansion sleeve clamp, which comprises a core rod assembly, a main support welding inner and outer expansion sleeve clamp, and is characterized in that the core rod assembly comprises a core rod and a positioning structure, and the positioning structure is provided with a first step structure which is used for being arranged at one end of a main shell and realizing axial positioning between the main shell and a main support; a mounting seat assembly; the wedge-shaped block assembly comprises at least three wedge-shaped block sets arranged in the circumferential direction of the core rod, each wedge-shaped block set comprises an inner wedge-shaped block and an outer wedge-shaped block, the inclined face of the outer wedge-shaped block is tightly attached to the inclined face of the inner wedge-shaped block, and the outer wedge-shaped block is arranged at the end of the clamp; and the core adjusting assembly is used for controlling all the inner wedge-shaped blocks to move along the inclined planes of the outer wedge-shaped blocks at the same time, so that when the inner wedge-shaped blocks move towards one end of the clamp, the inner wedge-shaped blocks clamp the core rod, and meanwhile the outer wedge-shaped blocks move outwards to be tightly attached to the inner diameter of the stator. The assembling efficiency is high, and the coaxiality of the stator and the main support can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of main bracket welding, and particularly relates to an internal and external expansion sleeve fixture for main bracket welding. Background Art

[0002] One of the most core functional components of an air conditioner is its compressor, and the compressor includes core components such as a main housing, a stator, a rotor shaft system, and a shaft system support. After the stator and the rotor shaft system are assembled, an electric spindle similar to an internal motor is formed to provide a power source for the compressor. Generally, as Figure 5 、 Figure 6 shown, the compressor stator 2 and the main housing 1 are formed into one body by hot sleeving or welding; then the main bracket 3 and the main housing 1 are welded into one body. After the assembly is completed, it is necessary to ensure the coaxiality of the axis A of the stator 2 and the axis B of the main bracket 3.

[0003] The existing scheme of the rotor shaft system support seat welding fixture is: the fixture 4 is designed and manufactured with the main housing 1 as the process reference. The fixture 4 and the main housing 1, and the fixture 4 and the main bracket 3 are both radially positioned by means of clearance positioning and axially positioned by means of end face contact. After positioning, the main bracket 4 and the main housing 1 are welded.

[0004] Generally, on the premise that the roundness and perpendicularity of the workpiece are very good and the assembly beat requirement is slow, the positioning clearance between the positioning fixture and the workpiece can be designed to be small. However, in the mass production site of compressor assembly, the roundness accuracy of the compressor itself is not high and there are batch size consistency errors. In addition, the handling mechanism also has repeated positioning errors. Using the traditional technical scheme, since the main housing is used as the transition process reference, and to ensure the smoothness of clamping, generally, the positioning clearance between the fixture and the main housing needs to be greater than 0.15 mm, and this error will directly affect the coaxiality of the stator and the rotor. In addition, the coaxiality between the main housing and the inner hole of the stator will affect the coaxiality between the stator and the rotor. This traditional technical scheme is only applicable to the rotor main bracket welding with general accuracy grade requirements and low production beat requirements. Summary of the Invention

[0005] In order to solve the problem of low coaxiality between the stator and the main bracket during the main bracket welding in the existing method, the present invention provides an internal and external expansion sleeve fixture for main bracket welding, which not only has high assembly efficiency but also can improve the coaxiality between the stator and the main bracket.

[0006] The object of the present invention is achieved by the following technical solutions: The present invention discloses an internal and external expansion sleeve fixture for main bracket welding, including: Mandrel assembly, the mandrel assembly includes a mandrel and a positioning structure for fixing the mandrel and mounted on the main bracket to make the axis of the mandrel coincide with the axis of the main bracket, and a first step structure for being placed at one end of the main housing and realizing axial positioning between the main housing and the main bracket is provided on the positioning structure; Mounting seat assembly, the mounting seat assembly includes a mounting seat, and a second step structure for fixing a fixture and a third step structure for realizing axial and radial limits of the main housing are provided on the mounting seat; Wedge block assembly, the wedge block assembly includes at least 3 wedge block groups circumferentially arranged on the mandrel, and each wedge block group includes an inner wedge block and an outer wedge block whose inclined surface is in close contact with the inclined surface of the inner wedge block and is placed at the end of the fixture; Core alignment assembly, the core alignment assembly is used to control all inner wedge blocks to move along the inclined surface of the outer wedge block simultaneously, so that when the inner wedge blocks move towards one end of the fixture, the inner wedge blocks clamp the mandrel while the outer wedge blocks move outwards and are in close contact with the inner diameter of the stator.

[0007] Compared with the prior art, the present invention has at least the following advantages and beneficial effects: In the present invention, a mandrel assembly is fixed on the main bracket, the mandrel of the mandrel assembly is coaxial with the main bracket, the axis of the main bracket is extended to the stator by using the mandrel, and the inner wedge blocks are driven to move downwards by the core alignment assembly, driving the pull rod to move downwards for core alignment, so as to realize the adjustment of the coaxiality between the axis of the main bracket and the axis of the stator. By adopting this solution, not only the assembly efficiency is high, but also the coaxiality of the main bracket and the stator is improved. Description of the Drawings

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0009] Figure 1 It is a schematic structural diagram of the inner and outer expansion sleeve fixture welded to the main bracket of the present invention; Figure 2 It is a schematic structural diagram of the mandrel assembly; Figure 3 It is a schematic structural diagram of the mandrel assembly mounted on the main bracket; Figure 4 It is a cross-sectional view of the core alignment assembly, the inner wedge blocks and the mounting seat assembly; Figure 5 It is a schematic structural diagram of the existing stator and the main housing; Figure 6 It is a schematic structural diagram of the existing main bracket.

[0010] In the figure, 1 is the main housing, 2 is the stator, 3 is the main bracket, 4 is the fixture, 51 is the mandrel, 52 is the fixed seat, 53 is the first stepped structure, 54 is the positioning pin, 55 is the connecting structure, 6 is the mounting seat, 61 is the second stepped structure, 62 is the third stepped structure, 71 is the inner wedge block, 72 is the outer wedge block, 81 is the pull rod, 811 is the mounting hole, 812 is the pressing plate, 813 is the limit projection, 82 is the pushing cylinder, 83 is the spring, 84 is the guide sleeve, 91 is the spring sleeve, 92 is the rubber ring, and 93 is the anti-rotation rod. Specific Embodiments

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0013] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0014] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0015] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship when the product of the present invention is normally placed, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0016] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "linked" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0017] In order to improve the coaxiality between the stator and the main bracket during the welding process, the present invention discloses a main bracket welding inner and outer expansion sleeve fixture. As Figures 1 to 4 shown, the main bracket welding inner and outer expansion sleeve fixture of the present invention includes a mandrel assembly, a mounting seat assembly, a wedge block assembly, and a centering adjustment assembly. Among them, the mandrel assembly is used to extend the axis of the main bracket 3; the mounting seat assembly is used to fix the fixture and the main housing 1, and achieve the axial and radial positioning of the fixture and the main housing 1; the outer diameter and inner diameter lengths of the wedge block assembly are adjustable to adjust the axis between the fixture and the mandrel assembly, and finally make the two coaxial; the centering adjustment assembly is used to control the outer diameter and inner diameter lengths of the wedge block assembly.

[0018] Specifically, as Figure 2 shown, the mandrel assembly includes a mandrel 51 and a positioning structure. Among them, the mandrel 51 is fixed on the positioning structure, and the positioning structure is used to be installed on the main bracket 3 so that the axis C of the mandrel coincides with the axis of the main bracket, and a first step structure 53 for placing one end of the main housing 1 and realizing the axial positioning between the main housing 1 and the main bracket 3 is provided on the positioning structure. That is, as Figure 3 shown, after the positioning structure is installed on the main bracket 3, the length of the axis of the main bracket is extended. As Figure 1 shown, after the first step structure 53 of the positioning structure is placed at one end of the main housing 1, the axial positioning between the main bracket 3 and this end of the main housing 1 can be realized.

[0019] As Figure 1 shown, the mounting seat assembly includes a mounting seat 6. A second step structure 61 for fixing the fixture 4 and a third step structure 62 for realizing the axial and radial limits of the main housing 1 are provided on the mounting seat 6. That is, the second step structure 61 and the third step structure 62 simultaneously realize the axial and radial positioning of the fixture 4 and the main housing 1.

[0020] As Figure 1 、 Figure 4As shown in the figure, the wedge block assembly is placed in the stator. It includes at least three wedge block groups circumferentially arranged on the mandrel 51. Each wedge block group includes an inner wedge block 71 and an outer wedge block 72 whose inclined surface is in close contact with the inclined surface of the inner wedge block 71 and is placed at the end of the fixture 4. The inner wedge blocks 71 of each wedge block group have the same structure and specifications, and the outer wedge blocks 72 of each wedge block group have the same structure and specifications. Both the inner wedge block 71 and the outer wedge block 72 have a structure with an inclined surface on one side and a vertical surface on the other side. It should be noted that the vertical surface here refers to the state where this surface is parallel to the axis of the mandrel 51. The outer wedge block 72 is placed at the end of the fixture 4. Since the axis of the fixture is in a positioned state, the outer wedge block 72 is also in a fixed state axially, but the outer wedge block 72 is in a movable state radially. The inclined surface of the inner wedge block 71 is in close contact with the inclined surface of the outer wedge block 72, so the inner wedge block 71 is in a movable state both axially and radially.

[0021] The core alignment assembly is used to control all the inner wedge blocks 71 to move along the inclined surface of the outer wedge block 72 simultaneously. When the inner wedge block 71 moves towards one end of the fixture 4, while the inner wedge block 71 clamps the mandrel 51, the outer wedge block 72 moves outwards and is in close contact with the inner diameter of the stator 2. Since the inner wedge block 71 is in a movable state both axially and radially, when the core alignment assembly controls the inner wedge block 71 to move down along the inclined surface of the outer wedge block 72, the inclined surface squeezes the inner wedge block 71 to move outwards and be in close contact with the inner diameter of the stator 2. When the inner wedge block 71 clamps the mandrel 51 and the outer wedge block 72 moves outwards and is in close contact with the inner diameter of the stator 2, the axis of the mandrel 51 is adjusted to be coaxial with the axis of the fixture, that is, the axes of the main bracket 3, the fixture, and the main housing 1 are made coaxial.

[0022] Adopting the above structure can not only improve the coaxiality among the main bracket 3, the fixture, and the stator, but also achieve rapid adjustment.

[0023] The positioning structure is used to be installed on the main bracket 3, and there are many ways to realize it. For the convenience of rapid installation, as Figure 2 、 Figure 3 shown, the positioning structure includes a fixed seat 52, a positioning pin 54 arranged at one end of the fixed seat 52, and a connection structure 55 for fixing the fixed seat 52 and the main bracket 3. The first step structure 53 is arranged on the fixed seat 52. During installation, after aligning the positioning pin 54 with the positioning hole on the main bracket 3, the connection structure 55 can be installed. The connection structure 55 preferably uses bolts.

[0024] The first step structure 53 is annular, and the positioning pin 54 and the connection structure 55 are placed inside the first step structure 53.

[0025] The centering component realizes the movement control of the inner wedge block 71, and there are many implementation methods. For example, a structure of a pull rod 81 and a push cylinder 82 is adopted. One end of the pull rod 81 is used to fix the inner wedge block 71, and the output shaft of the push cylinder 82 is connected to the other end of the pull rod 81 to realize the axial movement control of the pull rod 81. However, with this structure, during the process of controlling the downward movement of the pull rod, it will automatically stop after the adjustment is in place. Preferably, a spring is used to realize the downward movement control of the pull rod 81. Specifically, referring to Figure 1 , Figure 4 , the centering component includes a pull rod 81, a push cylinder 82 and a spring 83.

[0026] Among them, one end of the pull rod is cylindrical, and mounting holes 811 for installing the inner wedge block 71 are provided around this end, so that the inner side surface and the inclined surface of the inner wedge block 71 are respectively located on the inner and outer sides of the pull rod. A pressing plate 812 is fixed to the other end, and the pressing plate is arranged on the periphery of the pull rod. The push cylinder 82 is placed at the bottom of the mounting seat 6, and its output shaft abuts against one end of the pull rod 81, that is, there is no connection relationship between the output shaft of the push cylinder 82 and the pull rod 81. The push cylinder 82 can push the pull rod 81 to move upward, but cannot pull the pull rod 81 to move downward. A spring installation cavity is provided at the bottom of the mounting seat 6. The spring installation cavity is located around the pull rod 81. The spring 83 is placed between the mounting seat 6 and the pressing plate 812 and is used to push the pull rod 81 to move toward the push cylinder 82 side, that is, the spring is compressed, and this force acts on the pressing plate 812 to have the effect of driving the pull rod 81 to move downward.

[0027] With the above structure, after the overall installation of the fixture, the main housing 1 and the stator to the mounting seat assembly, control the output shaft of the push cylinder 82 to move upward to drive the pull rod 81 to move upward, so as to increase the diameter of the circle where the inner wedge block 71 is located. Install the main bracket 3 and the mandrel assembly as a whole to the main housing 1. At this time, the mandrel 51 is placed in the middle of a plurality of inner wedge blocks 71. Then control the output shaft of the push cylinder 82 to move downward. At this time, since the spring is compressed, its compression force acts on the pressing plate 812 to drive the pull rod 81 to move downward. During the downward movement, while the inner wedge block 71 pushes the outer wedge block 72 to move outward, the inner side surface of the inner wedge block 71 moves toward the mandrel 51 until the inner wedge block 71 clamps the mandrel 51 and the outer wedge block 72 is in close contact with the inner diameter of the stator 2.

[0028] With the above structure, the downward movement of the pull rod is driven by the acting force of the spring, and the magnitude of the spring force can be adjusted by changing the specifications of the spring to ensure that the clamping of the wedge block assembly does not cause deformation of the workpiece during clamping, so as to obtain high-precision stability.

[0029] To improve the stability of the downward movement of the pull rod and realize the coaxiality adjustment accuracy, the pressing plate 812 is annular, and a plurality of springs are provided and evenly arranged around the mandrel 51.

[0030] The wedge block groups can be set to any number greater than or equal to 3 as needed, such as 3, 4, 5, 6, 7, 8, 9, etc., which can be evenly arranged around the pull rod 81.

[0031] In order to improve the stability of the pull rod and avoid relative rotation with the mounting seat during the alignment process, a rotation-stopping structure is provided between the pull rod 81 and the mounting seat 6 to limit the rotation of the pull rod 81. There are many ways to implement the rotation-stopping structure. For ease of installation, illustratively, the rotation-stopping structure is a rotation-stopping rod 93, and the pull rod 81 and the mounting seat 6 are both provided with a rotation-stopping hole for installing the rotation-stopping rod 93. The rotation-stopping hole is a bar-shaped hole, which is arranged along the axis direction of the pull rod 81.

[0032] One side of the inner wedge block 71 and the outer wedge block 72 is an inclined surface, and the other side is a plumb surface. The inner wedge block 71 is installed at the mounting hole 811 of the pull rod, and there are various ways to install it, such as using adhesive or other fixed connection. However, the fixed connection method is not convenient for maintenance and replacement and is not conducive to installation. In order to improve the installation stability of the inner wedge block 71 and the convenience of installing the inner wedge block 71, as shown in FIG. Figure 4 As shown, the pull rod is provided with limiting protrusions 813 for limiting the two ends of the inner wedge block 71. The two limiting protrusions 813 clamp the inner wedge block 71 from both ends. The inner wedge block 71 is placed on one side of the pull rod 81 and has at least two protrusion structures, and each protrusion structure is placed in a corresponding mounting hole 811. With this structure, radial movement of the inner wedge block 71 relative to the pull rod can be avoided during the core alignment process. Figure 4 As shown, the inner wedge block 71 is placed on one side of the pull rod 81 and has two protruding structures. At this time, the two protruding structures are respectively suitable for the two mounting holes 811. The end faces of the protruding structures on the same inner wedge block 71 are placed in the same plane.

[0033] On the basis of any of the above structures, in order to facilitate the installation of the core rod 51, the core adjustment assembly also includes a guide sleeve 84 placed at the end of the pull rod 81 and used to guide the installation of the core rod 51, and the diameter of the guide sleeve 84 at the end away from the pull rod 81 is larger than the diameter at the end close to the pull rod 81.

[0034] On the basis of any of the above structures, in order to protect the core rod 51 and the stator 2 during the core alignment process, to prevent the wedge block from directly contacting the core rod 51 and the stator 2 and to ensure the clearance requirement between the workpiece and the fixture, an elastic member is provided on the inner side surface of the inner wedge block 71 and / or the outer side surface of the outer wedge block 72. Exemplarily, the elastic member on the inner side surface of the inner wedge block 71 is a spring sleeve 91. The elastic member on the outer side surface of the outer wedge block 72 is a rubber ring 92.

[0035] By setting the spring sleeve 91 and the rubber ring 92, and utilizing the strong outward elasticity of the spring sleeve and the inward contraction of the rubber sealing ring on the outer circumference, a sufficient gap of at least 0.5 mm on one side between the workpiece and the fixture can be achieved, so as to meet the requirement of reducing the repeated positioning accuracy of the workpiece automatic loading and unloading mechanism, and a fully automatic production line with a high assembly beat requirement can be realized.

[0036] With the above structure, a mandrel assembly is fixed on the main bracket 3. The mandrel 51 of the mandrel assembly is coaxial with the main bracket 3. The axis of the main bracket 3 is extended to the stator by the mandrel 51. During the centering process, the wedge block assembly is placed between the stator and the mandrel 51. The inner wedge block 71 is driven upward by the pushing cylinder to facilitate the installation of the mandrel. After the mandrel is installed, the pushing cylinder is lowered. At this time, under the action of the spring, the pressing plate is pushed downward to drive the pull rod 81 to move towards the pushing cylinder 82 side, that is, the pull rod 81 is driven downward for centering, so as to realize the coaxiality adjustment of the axis of the main bracket and the axis of the stator.

[0037] With the above structure, when the pull rod moves downward, the wedge block assembly expands outward to clamp the stator and contracts inward to clamp the mandrel at the same time, so as to ensure that the compressor stator and the rotor support main bracket are positioned coaxially with each other as a reference and there is no positioning gap after clamping, so as to obtain a clamping and positioning with high coaxiality accuracy.

[0038] With the above device, the centering assembly is placed on the mounting seat. During installation, first assemble the mandrel assembly and the main bracket 3, then install the fixture on the mounting seat. After installing the outer wedge block at the corresponding position between the upper end face of the fixture and the inner wedge block 71, then install the main housing 1, the mandrel assembly and the main bracket 3 as a whole in sequence. The assembly process is simple and fast. Centering can be carried out after the assembly is completed.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A main bracket welding internal and external expansion sleeve fixture, characterized in that Comprising: A mandrel assembly, the mandrel assembly including a mandrel (51) and a positioning structure for fixing the mandrel (51) and mounted on the main bracket (3) to make the axis of the mandrel coincide with the axis of the main bracket, and a first step structure (53) for being placed at one end of the main housing (1) and realizing axial positioning between the main housing (1) and the main bracket (3) is provided on the positioning structure; A mounting seat assembly, the mounting seat assembly including a mounting seat (6), a second step structure (61) for fixing a fixture (4) and a third step structure (62) for realizing axial and radial limits of the main housing (1) are provided on the mounting seat (6); A wedge block assembly, the wedge block assembly including at least 3 wedge block groups circumferentially arranged on the mandrel (51), each wedge block group including an inner wedge block (71) and an outer wedge block (72) whose inclined surface is in close contact with the inclined surface of the inner wedge block (71) and is placed at the end of the fixture (4); A core alignment assembly, the core alignment assembly is used to control all the inner wedge blocks (71) to move along the inclined surface of the outer wedge block (72) simultaneously, so that when the inner wedge blocks (71) move towards one end of the fixture (4), the inner wedge blocks (71) clamp the mandrel (51) while the outer wedge blocks (72) move outwards and are in close contact with the inner diameter of the stator (2).

2. The internal and external expansion sleeve fixture for main bracket welding according to claim 1, wherein The positioning structure includes a fixed seat (52), a positioning pin (54) arranged at one end of the fixed seat (52), and a connection structure (55) for fixing the fixed seat (52) and the main bracket (3), and the first step structure (53) is arranged on the fixed seat (52).

3. A main bracket welding internal and external expansion sleeve fixture according to claim 1, characterized in that, The core alignment assembly includes: A pull rod (81), one end of the pull rod is cylindrical and mounting holes (811) for mounting the inner wedge blocks (71) are arranged around it so that the inner side surface and the inclined surface of the inner wedge blocks (71) are respectively placed on the inner and outer sides of the pull rod, and a pressing plate (812) is fixed at the other end; A pushing cylinder (82), the output shaft of the pushing cylinder (82) abuts against one end of the pull rod (81); A spring (83), the spring (83) is placed between the mounting seat (6) and the pressing plate (812) and is used to push the pull rod (81) to move towards the side of the pushing cylinder (82).

4. A main support welding internal and external expansion sleeve fixture according to claim 3, characterized in that A rotation stopping structure for restricting the rotation of the pull rod (81) is arranged between the pull rod (81) and the mounting seat (6).

5. A main bracket welding internal and external expansion sleeve fixture according to claim 4, characterized in that, The rotation stopping structure is a rotation stopping rod (93), and rotation stopping holes for mounting the rotation stopping rod (93) are arranged on both the pull rod (81) and the mounting seat (6).

6. A main bracket welding internal and external expansion sleeve fixture according to claim 3, characterized in that, Limit protrusions (813) for realizing limits at both ends of the inner wedge block (71) are arranged on the pull rod, and the inner wedge block (71) is placed on one side of the pull rod (81) and is in at least two protrusion structures and each protrusion structure is placed in the corresponding mounting hole (811).

7. A main bracket welding internal and external expansion sleeve fixture according to claim 3, characterized in that, The core alignment assembly further includes a guide sleeve (84) placed at the end of the pull rod (81) for guiding the installation of the mandrel (51), and the diameter of the end of the guide sleeve (84) far from the pull rod (81) is larger than the diameter of the end close to the pull rod (81).

8. A main bracket welding internal and external expansion sleeve fixture according to claim 1, characterized in that, An elastic member is provided on the inner side surface of the inner wedge block (71) and / or the outer side surface of the outer wedge block (72).

9. A main bracket welding internal and external expansion sleeve fixture according to claim 8, characterized in that, The elastic member on the inner side surface of the inner wedge block (71) is a spring sleeve (91).

10. The internal and external expansion sleeve fixture for welding of the main bracket according to claim 8, wherein The elastic member on the outer side surface of the outer wedge block (72) is a rubber ring (92).

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