A positioning device that simultaneously tightens the rear axle housing reinforcement ring and rear cover

Abstract

The present invention belongs to the technical field of rear axle housing positioning, and particularly relates to a positioning device for simultaneously tightening the rear axle housing reinforcement ring and rear cover. The device comprises a self-centering axle housing tightening device, a rear cover positioning device, and a self-centering clamping device for the square section of the axle housing. The self-centering axle housing tightening device moves radially to tighten and secure the rear axle housing reinforcement ring. The rear cover positioning device moves synchronously with the self-centering axle housing tightening device via a spring to tighten and position the rear cover. The center of the rear cover positioning device and the center of the self-centering axle housing tightening device are aligned on the same centerline. The self-centering clamping device for the square section of the axle housing automatically clamps the square section of the axle housing. This device solves the problem of circumferential weld deviation of the axle housing rear cover, which occurs when the positioning of the axle housing rear cover is not linked to the reinforcement ring.

Description

Technical Field

[0001] The invention belongs to the technical field of rear axle housing positioning, and in particular relates to a positioning device for simultaneously tightening a rear axle housing reinforcement ring and a rear cover. Background Art

[0002] During the welding process of the rear axle housing assembly, it is necessary to ensure that the coaxiality of the bridge housing rear cover and the reinforcement ring is ≤0.5, otherwise it is easy to cause the bridge housing rear cover to be welded off-center, which will lead to oil leakage and seriously affect the product quality. In the early days, spot welding of the bridge housing rear cover was performed by visually drawing a circle. The positioning of the bridge housing rear cover had nothing to do with the reinforcement ring, and the spot welding was performed entirely based on the workers' experience, which led to the subsequent circumferential weld of the bridge housing rear cover being prone to welding off-center. The later positioning tooling has been improved, and the inner hole and notch of the reinforcement ring are used to position the bridge housing body. The positioning plate 14 for positioning the rear cover is connected to the bottom positioning block 10 through the guide column 11, the intermediate screw 12, and the compression spring 16. It is used for axial positioning of the rear cover, and the rear cover positioning shaft 13 is passed through the oil filler plug seat hole to determine the angular direction of the rear cover.

[0003] The current positioning method of the bridge housing rear cover has the following disadvantages:

[0004] 1. The rear cover positioning method is not based on the inner hole of the reinforcement ring. It is necessary to ensure that the positioning tooling has high accuracy and high cost.

[0005] 2. After the bottom reinforcement ring positioning block 10 is worn, the bridge housing body will have axial offset, which will inevitably cause the rear cover welding to be offset.

[0006] 3. After the upper rear cover positioning plate 14 is worn, a gap is generated between the rear cover inner cavity and the positioning plate 14, which will inevitably cause the rear cover to be welded off-center.

[0007] 4. When replacing different types of bridge housings, it is necessary to replace different rear cover positioning tooling, which is time-consuming and labor-intensive.

[0008] 5. During use, the bridge shell needs to be lifted to the top of the bottom reinforcement ring positioning plate. The loading time is too long, affecting production efficiency. Summary of the Invention

[0009] The purpose of the present invention is to provide a positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover. The device uses the inner hole of the reinforcement ring as a reference to position the rear cover. The device can position the rear cover while tightening the reinforcement ring, and associates the positioning of the rear cover with the reinforcement ring, thereby solving the problem that the circumferential weld of the rear cover of the bridge housing is easily deflected due to the fact that the positioning of the rear cover of the bridge housing is not associated with the reinforcement ring.

[0010] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0011] A positioning device for simultaneously tightening the rear axle housing reinforcement ring and rear cover, comprising an axle housing self-centering tightening device, a rear cover positioning device, and an axle housing square section self-centering clamping device;

[0012] The bridge housing self-centering and tightening device moves radially and is used to tighten and fix the rear axle housing reinforcement ring. The rear cover positioning device moves synchronously with the bridge housing self-centering and tightening device through a spring and is used to tighten and position the rear cover. The center of the rear cover positioning device and the center of the bridge housing self-centering and tightening device are on the same center line. The bridge housing square section self-centering clamping device is used to automatically clamp the square section of the bridge housing.

[0013] The preferred options are as follows:

[0014] Preferably: the bridge housing self-centering tightening device includes a three-jaw pneumatic chuck and three jaws, the bottom of the three-jaw pneumatic chuck is fixedly connected to the top of the workbench, and the tops of the three wedge blocks of the three-jaw pneumatic chuck are respectively installed with the jaws, the jaws are L-shaped, the top of the jaws is provided with a plurality of bolt mounting holes, the bottom of the jaws is provided with bar patterns, the bottom of the jaws is inserted into the bolt mounting holes by bolts and fixedly connected to the top of the three-jaw pneumatic chuck, the inner corner of the L-shape of the jaws is provided with a stepped platform, the outer side of the stepped platform is arc-shaped, the stepped platform is used to tighten the inner hole of the rear axle housing reinforcement ring, the top of the right end of the jaw is used to support the rear axle housing reinforcement ring, the front and rear ends of the left side of the jaw are respectively provided with protrusions, and the protrusions are provided with pin shaft insertion holes in the horizontal direction.

[0015] Preferably: the rear cover positioning device includes a mounting plate, an intermediate guide column, a spring, a connecting rod and a positioning rod, the bottom of the mounting plate is fixedly connected to the top of the three-jaw pneumatic chuck, the center of the mounting plate coincides with the center of the three-jaw pneumatic chuck, the bottom of the intermediate guide column is fixedly connected to the top center of the mounting plate, the intermediate guide column is located at the center of the three jaws, the connecting rod is in an inverted L shape, the top of the connecting rod is located above the top of the jaws, the upper end of the connecting rod is fixedly connected to the side of the jaws by a bolt, and the lower end of the connecting rod is located at Between the two protrusions, the lower end of the connecting rod is movably connected to the pin shaft insertion hole through a pin shaft and a cotter pin. The spring is provided between the intermediate guide column and the lower end of the connecting rod. The two ends of the spring are respectively fixedly connected to the intermediate guide column and the lower end of the connecting rod. The spring is located below the pin shaft insertion hole. The connecting rod keeps synchronous movement with the claw under the action of the spring, thereby tightening and fixing the inner cavity surface of the rear cover. The bottom of the positioning rod is fixedly connected to the top of the mounting plate, and the positioning rod is used to pass through the oil filling plug seat hole of the rear cover.

[0016] Preferably: the intermediate guide column is provided with three spring mounting blocks at intervals along the circumferential direction, the spring mounting blocks correspond to the claws one by one, the spring mounting blocks are provided with a spring mounting hole A, the lower end of the connecting rod is provided with a spring mounting hole B, and the two ends of the spring are fixedly connected to the spring mounting hole A and the spring mounting hole B respectively.

[0017] Preferably, the top right end of the connecting rod is movably connected to a bearing via a pin shaft and a cotter pin, and the bearing is used to tighten the inner cavity surface of the rear cover.

[0018] Preferably: the square section self-centering clamping device of the bridge housing includes a mounting seat, a large-diameter opening clamp and a clamp, the bottom of the mounting seat is fixedly connected to the top of the workbench, the large-diameter opening clamp is horizontally placed and fixedly connected to the top of the mounting seat, the clamps are respectively installed on the clamps at both ends of the large-diameter opening clamp, and the clamps at both ends of the large-diameter opening clamp drive the two clamps to move toward each other synchronously, thereby fixing and clamping the square section of the bridge housing.

[0019] Preferably: the clamp includes a clamping plate, a horizontal plate and a vertical plate, the clamping plate and the vertical plate are arranged vertically parallel and spaced apart, the horizontal plate is located between the clamping plate and the vertical plate, the left and right ends of the horizontal plate are fixedly connected to the side of the clamping plate and the side of the vertical plate respectively, the side of the vertical plate is fixedly connected to the clamping claws at both ends of the large-diameter opening clamp, so that the two clamping plates are arranged facing each other.

[0020] Preferably, a triangular reinforcing plate is installed at the connection between the clamping plate and the transverse plate.

[0021] In summary, the present invention has the following beneficial effects:

[0022] 1. The centers of the axle housing self-centering and tightening device and the rear cover positioning device in the present invention are on the same center line, and the axle housing self-centering and tightening device can drive the rear cover positioning device to move synchronously during the process of tightening the rear axle housing reinforcement ring, so that the center of the rear axle housing reinforcement ring and the center of the rear cover are on the same center line, and the positioning of the rear cover is associated with the reinforcement ring, which can effectively improve the coaxiality between the rear axle housing reinforcement ring and the rear cover, and avoid the circumferential weld deviation of the rear cover.

[0023] 2. By adjusting the distance between the three claws, the rear axle housing reinforcement rings of different models can be tightened. The tightening range of the claws can be freely adjusted and has strong versatility.

[0024] 3. After the jaws are worn, the installation position between the jaws and the wedge block of the three-jaw pneumatic chuck can be adjusted to adjust the clamping range of the jaws after wear and compensate for the clamping accuracy of the jaws. There is no need to replace the tooling, which reduces the tooling production cost and reduces costs.

[0025] 4. The tightening and fixing of the rear axle housing reinforcement ring, the positioning of the rear cover, and the clamping and fixing of the square section of the axle housing are all achieved by pneumatic means, saving time and effort, reducing labor intensity, and improving production efficiency; BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of the positioning device in the embodiment for positioning and clamping the bridge housing. Figure I ;

[0027] Figure 2 This is a schematic diagram of the structure of the positioning device in the embodiment for positioning and clamping the bridge housing. Figure II ;

[0028] Figure 3 is a schematic structural diagram of a positioning device in an embodiment;

[0029] Figure 4 2. It is a schematic structural diagram of the axle housing self-centering and tightening device and the rear cover positioning device in the embodiment;

[0030] Figure 5 This is a schematic diagram of the structure of the bridge housing self-centering support device and the rear cover positioning device (excluding the claws) in the embodiment. Figure I ;

[0031] Figure 6 This is a schematic diagram of the structure of the bridge housing self-centering support device and the rear cover positioning device (excluding the claws) in the embodiment. Figure II ;

[0032] Figure 7 2. It is a structural diagram of the axle housing self-centering and tightening device in the embodiment;

[0033] Figure 8 2. It is a schematic structural diagram of the self-centering clamping device for the square cross-section of the axle housing in the embodiment;

[0034] Figure 9 It is a structural schematic diagram of the improved positioning tooling in the background technology;

[0035] Figure 10 yes Figure 9 Schematic diagram of the structure of the positioning tooling and the rear axle housing.

[0036] In the figure, 1. axle housing self-centering and tightening device; 2. rear cover positioning device; 3. axle housing square section self-centering clamping device; 4. workbench; 5. rear axle housing reinforcement ring; 6. rear cover; 7. axle housing square section; 8. base; 9. bottom plate; 10. positioning block; 11. guide post; 12. intermediate screw; 13. rear cover positioning shaft; 14. positioning plate; 15. guide sleeve; 16. compression spring; 17. L-shaped plate; 18. threaded rod; 111. three-jaw solid pneumatic chuck; 112. wedge Shaped block; 113, claw; 114, step; 115, protrusion; 116, pin insertion hole; 117, bolt mounting hole; 118, bar pattern; 221, mounting plate; 222, intermediate guide column; 223, spring; 224, spring mounting block; 225, connecting rod; 226, positioning rod; 227, bearing; 331, mounting seat; 332, large-diameter opening clamp; 333, clamping plate; 334, horizontal plate; 335, vertical plate; 336, triangular reinforcement plate. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] Identical components are denoted by the same reference numerals. It should be noted that the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," and "outer" used in the following description refer to directions in the drawings, but are not intended to be limiting.

[0039] like Figures 1-10 As shown, a positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover comprises a bridge housing self-centering tightening device 1, a rear cover positioning device 2 and a bridge housing square section self-centering clamping device 3; the bridge housing self-centering tightening device 1 moves radially to tighten and fix the rear axle housing reinforcement ring 5, the rear cover positioning device 2 moves synchronously with the bridge housing self-centering tightening device 1 through a spring 223 to tighten and position the rear cover 6, the center of the rear cover positioning device 2 is on the same center line as the center of the bridge housing self-centering tightening device 1, and the bridge housing square section self-centering clamping device 3 is used to automatically clamp the bridge housing square section 7.

[0040] The bridge housing self-centering and tightening device 1 includes a three-jaw solid pneumatic chuck 111 and three claws 113. The bottom of the three-jaw solid pneumatic chuck 111 is fixedly connected to the top of the workbench 4. The tops of the three wedge blocks 112 of the three-jaw solid pneumatic chuck 111 are respectively equipped with claws 113. The claws 113 are L-shaped. The tops of the claws 113 are provided with several bolt mounting holes 117. The bottoms of the claws 113 are provided with bar patterns 118. The bottoms of the claws 113 are screwed in place. The bolt is inserted into the bolt mounting hole 117 and fixedly connected to the top of the three-jaw pneumatic chuck 111. A stepped platform 114 is provided at the inner corner of the L-shaped claw 113. The outer side of the stepped platform 114 is arc-shaped. The stepped platform 114 is used to tighten the inner hole of the rear axle housing reinforcement ring 5. The top of the right end of the claw 113 is used to support the rear axle housing reinforcement ring 5. The front and rear ends of the left side of the claw 113 are respectively provided with protrusions 115, and the protrusion 115 is provided with a pin shaft insertion hole 116 in the horizontal direction.

[0041] The rear cover positioning device 2 includes a mounting plate 221, an intermediate guide column 222, a spring 223, a connecting rod 225 and a positioning rod 226. The bottom of the mounting plate 221 is fixedly connected to the top of the three-jaw solid pneumatic chuck 111, and the center of the mounting plate 221 coincides with the center of the three-jaw solid pneumatic chuck 111. The bottom of the intermediate guide column 222 is fixedly connected to the top center of the mounting plate 221. The intermediate guide column 222 is located at the center of the three claws 113. The connecting rod 225 is in an inverted L shape. The top of the connecting rod 225 is located above the top of the claw 113. The upper end of the connecting rod 225 is fixedly connected to the side of the claw 113 by a bolt. The lower end of the connecting rod 225 is located between the two protrusions 115. The lower end of the connecting rod 225 is connected to the pin shaft, the cotter pin and the pin shaft through hole 11 6 is movably connected. A spring 223 is disposed between the middle guide post 222 and the lower end of the connecting rod 225. Three spring mounting blocks 224 are spaced circumferentially between the middle guide post 222. These spring mounting blocks 224 correspond to the claws 113 one-to-one. Spring mounting holes A are defined in the spring mounting blocks 224. The lower end of the connecting rod 225 defines a spring mounting hole B. The ends of the spring 223 are fixedly connected to the spring mounting holes A and B, respectively. The spring 223 is located below the pin insertion hole 116. Under the action of the spring 223, the connecting rod 225 moves synchronously with the claws 113, thereby tightening and securing the inner surface of the rear cover 6. The bottom of a positioning rod 226 is fixedly connected to the top of the mounting plate 221. Positioning rod 226 is designed to pass through the oil plug seat hole in the rear cover 6. The top right end of the connecting rod 225 is movably connected to a bearing 227 via a pin and a cotter pin. Bearing 227 is used to tighten the inner surface of the rear cover 6.

[0042] The self-centering clamping device 3 for the square section of the axle housing comprises a mounting base 331, a large-diameter open clamp 332, and a clamp. The bottom of the mounting base 331 is fixedly connected to the top of the workbench 4. The large-diameter open clamp 332 is horizontally positioned and fixedly connected to the top of the mounting base 331. The jaws at each end of the large-diameter open clamp 332 are respectively equipped with clamps. The jaws at each end of the large-diameter open clamp 332 drive the two clamps to move synchronously toward each other, thereby securing and clamping the square section of the axle housing 7. The clamp comprises a clamping plate 333, a horizontal plate 334, and a vertical plate 335. The clamping plate 333 and the vertical plate 335 are arranged vertically, parallel, and spaced apart. The horizontal plate 334 is located between the clamping plate 333 and the vertical plate 335. The left and right ends of the horizontal plate 334 are fixedly connected to the side surfaces of the clamping plate 333 and the side surfaces of the vertical plate 335, respectively. The side surfaces of the vertical plate 335 are fixedly connected to the jaws at each end of the large-diameter open clamp 332, so that the two clamping plates 333 are positioned facing each other. A triangular reinforcing plate 336 is installed at the connection between the clamping plate 333 and the horizontal plate 334. The large-diameter opening clamp 332 is a 5HFT32X100S (0) type large-diameter opening clamp 332.

[0043] Specific implementation process:

[0044] Use a hoist to hoist the rear axle housing (with the reinforcement ring welded and facing downward) above workbench 4, aligning the rear axle housing reinforcement ring 5 with the axle housing self-centering bracing device 1. The rear axle housing reinforcement ring 5 is inverted and placed atop the right end of the L-shaped claw 113. The rear cover 6 is placed over the rear axle housing reinforcement ring 5, with the positioning rod 226 passing through the oil plug seat hole in the rear cover 6. The axle housing square section 7 is positioned between the two clamping plates 333 in the axle housing square section self-centering clamping device 3. The large-diameter open clamp 332 is activated, and the clamping claws at both ends of the large-diameter open clamp 332 drive the two clamping plates 333 toward each other, thereby clamping and securing the axle housing square section 7.

[0045] The top of the right end of the L-shaped claw 113 is used to support and fix the rear axle housing reinforcement ring 5. The three-jaw solid pneumatic chuck 111 is started. The three wedge blocks 112 of the three-jaw solid pneumatic chuck 111 drive the three claws 113 to move radially outward, so that the stepped platform 114 of the claw 113 gradually tightens the inner hole of the rear axle housing reinforcement ring 5. During the movement, the claw 113 drives the connecting rod 225 to move synchronously. Under the action of the spring 223 and the lever, the bearing 227 on the connecting rod 225 gradually tightens the inner cavity of the rear cover 6, thereby ensuring that the rear axle housing reinforcement ring 5 and the rear cover 6 are synchronously and accurately positioned, so that the positioning of the two is correlated, and the coaxiality of the positioning of the two is improved, which is beneficial for the operator to spot weld the circumferential weld of the rear cover 6.

[0046] Compared with the positioning fixture in the background art, the positioning device in the present invention has the following advantages:

[0047] a. The self-centering and tightening device 1 of the bridge housing in the present invention is to fix and position the rear axle housing by positioning and tightening the inner hole of the rear axle housing reinforcement ring 5. Compared with the positioning tool in the background technology that uses the bottom reinforcement ring positioning block 10 to position the reinforcement ring, the self-centering and tightening device 1 of the bridge housing in the present invention is simpler and faster to operate, has higher positioning accuracy, and can position different types of rear axle housing reinforcement rings 5, and has strong versatility; compared with the bottom reinforcement ring positioning block 10 in the background technology, after the bridge housing body is worn, it is easy to have axial deviation, resulting in the disadvantage of the rear cover welding deviation. After the claw 113 in the present invention is worn, the relative position between the claw 113 and the three wedge blocks 112 of the three-jaw pneumatic chuck 111 can be adjusted to adjust the tightening range of the three claws 113, thereby reducing the production cost of the overall device.

[0048] b. The rear cover positioning device 2 and the bridge housing self-centering and tightening device 1 in the present invention are coaxially positioned, and the positioning center of the rear cover positioning device 2 is the same as the positioning center of the bridge housing self-centering and tightening device 1, which can effectively improve the coaxiality of the rear cover 6 and the rear axle housing reinforcement ring 5, and ensure that the coaxiality of the rear cover 6 and the rear axle housing reinforcement ring 5 is ≤0.5. A bearing 227 is provided on the top of the connecting rod 225. The bearing 227 can tighten and fix the inner cavity surface of the rear cover 6 under the action of the claw 113 and the spring 223. The rear cover 6 is accurately positioned and tightened. There is no problem of a gap between the inner cavity of the rear cover and the positioning plate 14 after the upper rear cover positioning plate 14 is worn in the background technology, and there is no problem of the rear cover being easily welded off.

[0049] c. The axle housing self-centering and tightening device 1 of the present invention tightens and fixes the inner hole of the rear axle housing reinforcement ring 5 through the claws 113. The tightening range of the claws 113 can be adjusted. The rear cover positioning device 2 tightens and fixes the inner cavity surface of the rear cover 6 through the connecting rod 225. The center of the rear cover positioning device 2 coincides with the center of the axle housing self-centering and tightening device 1. The connecting rod 225 can also adjust the tightening range under the elastic force of the spring, and has strong versatility.

[0050] d. In the present invention, it is only necessary to hoist the inner hole of the rear axle housing reinforcement ring 5 downward onto the axle housing support surface at the top right end of the clamping claw 113, and then perform subsequent tightening and fixing. The work efficiency is high, and it overcomes the shortcomings of the background technology that the axle housing needs to be hoisted to the top of the bottom reinforcement ring positioning plate, the loading time is too long, and the production efficiency is low.

[0051] This specific embodiment is an illustration of the present invention, but it is not a limitation of the present invention. Changes, modifications, additions or substitutions made within the essential scope of the present invention should fall within the scope of protection of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover, characterized in that: A bridge housing self-centering bracing device (1), a rear cover positioning device (2), and a bridge housing square section self-centering clamping device (3); The bridge housing self-centering tightening device (1) moves in the radial direction and is used to tighten and fix the rear bridge housing reinforcement ring (5); the rear cover positioning device (2) moves synchronously with the bridge housing self-centering tightening device (1) through the spring (223) and is used to tighten and position the rear cover (6); the center of the rear cover positioning device (2) and the center of the bridge housing self-centering tightening device (1) are on the same center line; the bridge housing square section self-centering clamping device (3) is used to automatically clamp the bridge housing square section (7); The bridge housing self-centering and tightening device (1) comprises a three-jaw solid pneumatic chuck (111) and three claws (113), the bottom of the three-jaw solid pneumatic chuck (111) is fixedly connected to the top of the workbench (4), the tops of the three wedge blocks (112) of the three-jaw solid pneumatic chuck (111) are respectively installed with the claws (113), the claws (113) are L-shaped, the inner corners of the L-shaped claws (113) are provided with a stepped platform (114), the outer side of the stepped platform (114) is arc-shaped, the stepped platform (114) is used to tighten the inner hole of the rear bridge housing reinforcement ring (5), the top of the right end of the claw (113) is used to support the rear bridge housing reinforcement ring (5), the front and rear ends of the left side of the claw (113) are respectively provided with protrusions (115), and the protrusions (115) are provided with a pin shaft insertion hole (116) in the horizontal direction; The rear cover positioning device (2) comprises a mounting plate (221), an intermediate guide column (222), a spring (223), a connecting rod (225) and a positioning rod (226), wherein the bottom of the mounting plate (221) is fixedly connected to the top of the three-jaw solid pneumatic chuck (111), the center of the mounting plate (221) coincides with the center of the three-jaw solid pneumatic chuck (111), the bottom of the intermediate guide column (222) is fixedly connected to the top center of the mounting plate (221), the intermediate guide column (222) is located at the center of the three clamping jaws (113), the connecting rod (225) is in an inverted L shape, and the top of the connecting rod (225) is located above the top of the clamping jaws (113). The lower end of the connecting rod (225) is located between the two protrusions (115), and the lower end of the connecting rod (225) is movably connected to the pin shaft insertion hole (116) through a pin shaft and a cotter pin. The spring (223) is provided between the intermediate guide column (222) and the lower end of the connecting rod (225), and the two ends of the spring (223) are fixedly connected to the intermediate guide column (222) and the lower end of the connecting rod (225), respectively. The spring (223) is located below the pin shaft insertion hole (116). Under the action of the spring (223), the connecting rod (225) keeps synchronous movement with the claw (113), thereby tightening and fixing the inner cavity surface of the rear cover (6).

2. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 1, characterized in that: The top of the clamping jaw (113) is provided with a plurality of bolt mounting holes (117), the bottom of the clamping jaw (113) is provided with a bar pattern (118), and the bottom of the clamping jaw (113) is fixedly connected to the top of the three-jaw pneumatic chuck (111) by inserting bolts into the bolt mounting holes (117).

3. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 2, characterized in that: The bottom of the positioning rod (226) is fixedly connected to the top of the mounting plate (221), and the positioning rod (226) is used to pass through the oil plug seat hole of the rear cover (6).

4. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 3, characterized in that: The intermediate guide column (222) is provided with three spring mounting blocks (224) spaced apart along the circumferential direction. The spring mounting blocks (224) correspond one to one with the claws (113). The spring mounting blocks (224) are provided with a spring mounting hole A. The lower end of the connecting rod (225) is provided with a spring mounting hole B. The two ends of the spring (223) are fixedly connected to the spring mounting hole A and the spring mounting hole B, respectively.

5. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 3, characterized in that: The top right end of the connecting rod (225) is movably connected to a bearing (227) via a pin shaft and a cotter pin, and the bearing (227) is used to tighten the inner cavity surface of the rear cover (6).

6. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 1, characterized in that: The self-centering clamping device (3) for the square cross-section of the bridge housing comprises a mounting seat (331), a large-diameter opening clamp (332) and a clamp, wherein the bottom of the mounting seat (331) is fixedly connected to the top of the workbench (4), the large-diameter opening clamp (332) is horizontally placed and fixedly connected to the top of the mounting seat (331), and the clamps are respectively installed on the clamps at both ends of the large-diameter opening clamp (332). The clamps are driven by the clamps at both ends of the large-diameter opening clamp (332) to move synchronously toward each other, thereby fixing and clamping the square cross-section of the bridge housing (7).

7. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 6, characterized in that: The clamp comprises a clamping plate (333), a horizontal plate (334) and a vertical plate (335), wherein the clamping plate (333) and the vertical plate (335) are arranged in parallel and spaced apart in a vertical direction, and the horizontal plate (334) is located between the clamping plate (333) and the vertical plate (335). The left and right ends of the horizontal plate (334) are respectively fixedly connected to the side surface of the clamping plate (333) and the side surface of the vertical plate (335), and the side surface of the vertical plate (335) is fixedly connected to the clamping claws at both ends of the large-caliber opening clamp (332), so that the two clamping plates (333) are arranged facing each other.

8. The positioning device for simultaneously tightening the rear axle housing reinforcement ring and the rear cover according to claim 7, characterized in that: A triangular reinforcement plate (336) is installed at the connection between the clamping plate (333) and the transverse plate (334).

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