A wheel hub axle tapping fixture and a method for machining wheel hub axles

Abstract

This invention relates to the field of wheel hub shaft machining technology, and particularly to a wheel hub shaft tapping fixture and a method for machining wheel hub shafts. The fixture includes a base, a support frame, a buffer assembly, clamps, a tilting table, and positioning pins. The support frame is vertically fixed on the base to support the flange bottom surface of the wheel hub shaft. The buffer assembly is detachably mounted on the top of the support frame and can elastically extend and retract vertically at the top of the support frame to elastically abut against the flange bottom surface of the wheel hub shaft. The clamps are fixedly mounted on the side of the support frame to clamp the wheel hub shaft body. This invention facilitates precise alternating positioning of multiple threaded holes, improves tapping quality, ensures the phase angle relationship between the threaded hole and the finished hole, and better protects the flatness of the wheel hub shaft flange bottom surface, ensuring good fit and connection with other parts during subsequent assembly.

Description

Technical Field

[0001] This invention relates to the field of wheel hub shaft machining technology, and in particular to a wheel hub shaft tapping fixture and a method for machining wheel hub shafts. Background Technology

[0002] The wheel hub shaft of the wheel reducer refers to the connecting shaft between the reducer and the wheel on a vehicle. Its function is to transmit power and reduce the speed of the wheel, thereby providing better traction and handling performance.

[0003] See Figure 9 The end face of the wheel hub shaft of the wheel-side reducer generally has 8 evenly distributed φ15.3+0.10 smooth holes, and in addition, there are 4 non-evenly distributed M10-7H threaded holes. There is a phase angle relationship between the threaded holes and the smooth holes. The dimensional tolerance requirement for the smooth holes is 0.1mm, and the positional tolerance requirement is φ0.3mm. The positional tolerance requirement for the threaded holes is φ0.3mm. Dimensional tolerance and positional tolerance are key characteristics, and CPK needs to reach 1.33 or higher.

[0004] Currently, the difficulty in machining the end face of the wheel hub shaft of the wheel-side reducer lies in the small tolerance of the smooth hole size, which requires drilling and reaming to ensure accuracy. The threaded hole requires drilling the pilot hole and tapping to complete. In order to ensure product accuracy and form and position tolerance, it needs to be machined on a machining center. However, machining in the same process results in a long machining cycle and low efficiency, which cannot meet production needs. Therefore, many companies choose to tap the pilot hole of the thread on a tapping machine to ensure the machining cycle and meet production requirements.

[0005] Using a tapping machine to tap the threaded holes introduces new technical problems: when the hub shaft is clamped onto the tapping machine's fixture, the positioning of multiple threaded holes is not precise enough. During tapping, the tapping tool and the threaded hole are prone to misalignment, resulting in poor tapping quality. This causes a significant change in the phase angle relationship between the tapped threaded hole and the finished hole, affecting the fit and connection of the hub shaft with other parts during later assembly. Furthermore, during the installation of the hub shaft, the bottom face of the hub shaft flange is easily damaged by the fixture, leading to poor flatness of the flange bottom surface, which also affects the fit and connection of the hub shaft with other parts during later assembly. Summary of the Invention

[0006] In view of this, the present invention proposes a wheel hub shaft tapping fixture and a method for machining wheel hub shafts, which facilitates precise alternating positioning of multiple threaded bottom holes, improves tapping quality, ensures the phase angle relationship between threaded holes and smooth holes, and can better protect the flatness of the bottom end face of the wheel hub shaft flange, ensuring good fit and connection with other parts during the later assembly of the wheel hub shaft.

[0007] The technical solution of this invention is implemented as follows: On one hand, the present invention provides a wheel hub axle tapping fixture and a method for machining wheel hub axles, including a base, a support frame, a buffer assembly, clamps, a tilting table, and a positioning pin, wherein... The support frame is fixedly mounted vertically on the base to support the bottom surface of the flange of the hub shaft; The buffer assembly is detachably mounted on the top of the support frame and can be elastically extended and retracted vertically at the top of the support frame to elastically abut against the bottom surface of the flange of the wheel hub shaft. The clamp is fixedly mounted on the side of the support frame and is used to clamp the axle body of the wheel hub shaft; The flipping platform is located on the side of the support frame and is fixedly mounted on the base. The upper end of the flipping platform is located above the buffer assembly and can be flipped in the vertical direction. One end of the positioning pin passes through the upper end of the tilting table and is used to be inserted vertically into the threaded bottom hole at the end face of the wheel hub shaft.

[0008] Based on the above technical solutions, preferably, one end of the positioning pin is conical and the other end is cylindrical, and the conical end of the positioning pin selectively abuts against the threaded bottom hole at the end face of the wheel hub shaft.

[0009] Based on the above technical solutions, preferably, the buffer assembly includes several supporting copper blocks, a compression spring, a guide rod, and a limiting nut, wherein, The support frame has a U-shaped opening on one side of its top, and the inner diameter of the U-shaped opening is larger than the diameter of the wheel hub shaft. The top of the support frame is provided with several storage slots, and the several storage slots are arranged in a circular array along the circumference of the U-shaped opening. A number of the aforementioned support copper blocks are arranged one-to-one in a number of the aforementioned storage slots, the support copper blocks and the corresponding storage slots are slidably connected, and the depth of the storage slots is greater than the vertical thickness of the support copper blocks; Several compression springs are provided in each of the storage slots. One end of each compression spring abuts against the bottom of the storage slot, and the other end is fixedly connected to the bottom of the supporting copper block. The guide rod extends vertically through the storage slot, with its upper end screwed to the bottom of the supporting copper block and its lower end screwed to the limiting nut. The limiting nut is located outside the receiving groove.

[0010] Based on the above technical solutions, preferably, the tilting table includes a column and a positioning plate, wherein, The column is fixedly mounted on the base; The positioning plate is hinged to the top of the column; The positioning plate has a through hole at the end away from the column; The positioning pin selectively inserts into the through hole, and the diameter of the positioning pin is equal to the inner diameter of the through hole.

[0011] Based on the above technical solutions, preferably, the tilting table further includes a damping rotating shaft, wherein, The damping shaft is disposed between the column and the positioning plate; One end of the damping shaft is fixedly connected to the column, and the other end is fixedly connected to the positioning plate.

[0012] Based on the above technical solutions, preferably, the clamp includes a first clamping plate and a second clamping plate, wherein, The first clamping plate is fixedly disposed on the side of the support frame; The second clamping plate is disposed on the side of the first clamping plate away from the support frame. One end of the first clamping plate and the second clamping plate are hinged together, and the other end is connected by bolts.

[0013] Based on the above technical solutions, preferably, the clamp further includes a pin and a cotter pin, wherein, The first clamping plate has a first groove at one end near the flipping table; The second clamping plate has a protrusion at one end near the flipping table, and the protrusion is disposed in the first groove; The pin passes through the first groove and the protrusion from top to bottom; The cotter pin is horizontally inserted through the lower end of the pin shaft.

[0014] Based on the above technical solutions, preferably, the clamp further includes a connecting screw and a hand-tightening nut, wherein, One end of the connecting screw is hinged to the end of the first clamping plate away from the first groove, and the other end can be flipped in the horizontal direction. The hand-tightening nut is screwed onto the end of the connecting screw away from the first clamping plate; The second clamping plate has a second groove on the end away from the protrusion, and the connecting screw is selectively fitted into the second groove.

[0015] Based on the above technical solutions, preferably, the clamp further includes a copper pad, wherein, V-shaped grooves are provided on the adjacent ends of the first clamping plate and the second clamping plate; The copper pad is fixed at one point on the groove wall of each of the V-shaped grooves.

[0016] On the other hand, the present invention also provides a method for machining a hub shaft, which uses the above-mentioned hub shaft tapping fixture to clamp the workpiece, and further includes the following steps: S1. Place the wheel hub shaft tapping fixture on the tapping machine's worktable, align it, and then tighten it with bolts. S2. Prepare the wheel hub shaft to be processed. Open the clamp and fit the shaft body of the wheel hub shaft into the U-shaped opening. Then, place the flange of the wheel hub shaft on the buffer assembly. The buffer assembly buffers the wheel hub shaft after it is placed. Then, the weight of the wheel hub shaft presses down on the buffer assembly, so that the top of the buffer assembly is aligned with the top of the support frame. At this time, the wheel hub shaft is placed on the top of the support frame. S3. Rotate the hub shaft for rough positioning, and close the clamps but do not clamp them tightly; S4. Flip the upper end of the flipping platform downwards so that it is pressed against the top surface of the hub shaft; S5. Insert one end of the positioning pin cone into the upper end of the flipping table and move it downward so that one end of the positioning pin cone is inserted into the threaded bottom hole at the end face of the wheel hub shaft and abuts against the opening of the threaded bottom hole. S6. Clamp the hub shaft with the clamp to fix the hub shaft, and tap the threaded bottom hole at the diagonal hole of the positioning pin with the tapping machine. S7. After processing is completed, remove the positioning pin, loosen the clamp, rotate the hub shaft, and process the next threaded bottom hole; S8. Repeat steps S5-S7. After all processing is completed, remove the positioning pin, flip the top of the tilting table upwards to open it, then open the clamps, remove the wheel hub shaft, and the processing is complete.

[0017] The wheel hub shaft tapping fixture and method for machining wheel hub shafts disclosed in this invention have the following advantages over the prior art: (1) By setting up a base, support frame, buffer assembly, clamp, flip table and positioning pin, it is convenient to use the positioning pin to make relatively accurate alternating positioning of the threaded bottom hole at the end face of the hub shaft, so as to facilitate the alignment of the tapping tool with the threaded bottom hole to be processed, so as to facilitate the processing of multiple threaded bottom holes one by one, improve the tapping quality, ensure the phase angle relationship between the tapped threaded hole and the smooth hole, ensure the fit and connection of the hub shaft with other parts during the later assembly, and the buffer assembly can buffer the hub shaft during installation, better protect the bottom end face of the hub shaft flange from damage, so as to protect the flatness of the flange bottom surface, and ensure the good fit and connection of the hub shaft with other parts during the later assembly.

[0018] (2) By setting the buffer component to be detachably mounted on the top of the support frame, it is convenient to maintain the buffer component and ensure the good buffering performance of the buffer component.

[0019] (3) By setting one end of the positioning pin to be conical, it can adapt to different hole diameters. This can eliminate the influence of the tolerance of the threaded bottom hole, so that the positioning pin can fit tightly with the threaded bottom hole, ensuring accurate positioning. It also facilitates the insertion and positioning of the threaded hole after tapping, and facilitates the alternating processing of the threaded bottom hole.

[0020] (4) By providing a U-shaped opening on one side of the top of the support frame, the top of the support frame is used to support the flange bottom surface of the hub shaft, and the U-shaped opening is used to fit on the outside of the hub shaft body, which facilitates the installation of the hub shaft and improves the clamping efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0022] Figure 1 This is a perspective view of a wheel hub axle tapping fixture according to the present invention; Figure 2 This is a top view of the clamps of the present invention; Figure 3 This is a perspective view of the clamps of the present invention; Figure 4 This is a perspective view of the tilting table of the present invention; Figure 5 This is a perspective view of a wheel hub shaft tapping fixture according to the present invention after clamping a wheel hub shaft; Figure 6 This is a schematic diagram of the positioning pin of the present invention in its positioning state; Figure 7 This is a perspective view of the positioning pin of the present invention; Figure 8 This is a schematic diagram of the connection structure between the buffer assembly and the support frame of the present invention; Figure 9 A 3D view of an existing wheel hub axle; In the diagram: 1. Base; 2. Support frame; 3. Buffer assembly; 4. Clamp; 5. Tilting table; 6. Positioning pin; 31. Supporting copper block; 32. Compression spring; 33. Guide rod; 34. Limiting nut; 41. First clamping plate; 42. Second clamping plate; 43. Pin; 44. Cotter pin; 45. Connecting screw; 46. Hand-tightening nut; 47. Copper pad; 51. Column; 52. Positioning plate; 53. Damping shaft; 201. U-shaped opening; 202. Storage groove; 401. First groove; 402. Protrusion; 403. Second groove; 404. V-shaped groove; 501. Through hole. Detailed Implementation

[0023] The technical solutions of this invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] like Figure 1-8 As shown, a wheel hub axle tapping fixture of the present invention includes a base 1, a support frame 2, a buffer assembly 3, a clamp 4, a tilting table 5, and a positioning pin 6.

[0025] The base 1 is used to install onto the worktable of the tapping machine. After installation, the base 1 is located below the tapping tool. Specifically, the base 1 is rectangular and has several U-shaped stepped holes on its side. The U-shaped stepped holes are used to install bolts, which facilitates the connection between the base 1 and the worktable. During installation, hexagonal socket head cap screws are used. The hexagonal socket head cap screws are inserted into the stepped holes and then screwed onto the worktable of the tapping machine to complete the installation.

[0026] The support frame 2 is vertically fixed on the base 1. Specifically, the support frame 2 is Z-shaped and includes a top plate, a vertical plate, and a bottom plate. The vertical plate is fixed between the top plate and the bottom plate, and the bottom plate is fixedly installed on the base 1 by bolts. A U-shaped opening 201 is provided on one side of the top plate of the support frame 2. The inner diameter of the U-shaped opening 201 is larger than the outer diameter of the wheel hub shaft and smaller than the outer diameter of the wheel hub shaft flange. For installation of the wheel hub shaft, refer to... Figure 5 The top of the support frame 2 is used to support the flange bottom surface of the hub shaft, and the U-shaped opening 201 is used to fit on the outside of the hub shaft body. Because of the U-shaped opening 201, it is convenient to install the hub shaft from the side and improve the clamping efficiency.

[0027] The buffer assembly 3 is detachably mounted on the top of the support frame 2 and can elastically extend and retract vertically at the top of the support frame 2 to elastically support the flange bottom surface of the wheel hub shaft. Specifically, the buffer assembly 3 includes several support copper blocks 31, compression springs 32, guide rods 33 and limiting nuts 34. A U-shaped opening 201 is provided on one side of the top of the support frame 2. The inner diameter of the U-shaped opening 201 is larger than the shaft diameter of the wheel hub shaft. The top of the support frame 2 is used to support the flange bottom surface of the wheel hub shaft, and the U-shaped opening 201 is used to fit around the outside of the shaft of the wheel hub shaft. This structure facilitates the installation of the wheel hub shaft and improves clamping efficiency.

[0028] The top of the support frame 2 is provided with several storage slots 202, which are arranged in a circular array around the circumference of the U-shaped opening 201. Several supporting copper blocks 31 are correspondingly placed in the storage slots 202. The supporting copper blocks 31 and the corresponding storage slots 202 are slidably connected. The depth of the storage slot 202 is greater than the vertical thickness of the supporting copper block 31. The length and width of the storage slots 202 and the supporting copper blocks 31 are equal to facilitate the removal of the supporting copper blocks 31 from the storage slots 202. Several compression springs 32 are provided in each storage slot 202. One end of the compression spring 32 abuts against the bottom of the storage slot 202, and the other end is fixedly connected to the bottom of the supporting copper block 31. A guide rod 33 vertically passes through the storage slot 202. The two ends of the guide rod 33 are threaded. The upper end of the guide rod 33 is screwed to the bottom of the supporting copper block 31, and the lower end of the guide rod 33 is used to screw on a limit. The positioning nut 34 is located outside the receiving groove 202 and is used to hold the support copper block 31 in the receiving groove 202. When installing the hub axle, the bottom end face of the hub axle flange first contacts the support copper block 31. Due to its own weight, the hub axle presses the support copper block 31 downward, causing it to sink into the receiving groove 202. During the sinking process, the compression spring 32 is compressed and deformed, and the guide rod 33 slides downward to buffer the downward pressure, thereby achieving buffering during hub axle installation. This prevents the hub axle from colliding with the top of the support frame 2, better protecting the bottom end face of the hub axle flange from damage, thus protecting the flatness of the flange bottom surface and ensuring good fit and connection with other parts during the later assembly of the hub axle. When the hub axle is removed from the support frame 2, the compression spring 32 rebounds and pushes the support copper block 31 upward, causing the top of the support copper block 31 to protrude from the top of the support frame 2.

[0029] In addition, the buffer assembly 3 is detachably installed at the top of the support frame 2. After the limit nut 34 is removed, the support copper block 31 can be slid upward from the storage groove 202 and then the guide rod 33 and the support copper block 31 can be separated, which facilitates the replacement or maintenance of the support copper block 31 and the cleaning of the storage groove 202, ensuring the good buffering performance of the buffer assembly 3. To improve the sliding effect, a small amount of lubricating oil is injected into the storage groove 202.

[0030] The clamp 4 is fixedly installed on the side of the support frame 2 and is used to clamp the axle body of the wheel hub. Specifically, the clamp 4 includes a first clamping plate 41 and a second clamping plate 42. The first clamping plate 41 is fixedly installed on the side of the support frame 2, and the second clamping plate 42 is installed on the side of the first clamping plate 41 away from the support frame 2. One end of the first clamping plate 41 and the second clamping plate 42 are hinged together, and the other end is connected by bolts.

[0031] In the connection structure of the first clamping plate 41 and the second clamping plate 42, one end of the first clamping plate 41 and the second clamping plate 42 are connected by a pin 43, on which a cotter pin 44 is installed. The other end is connected by a connecting screw 45 and a hand-tightening nut 46. Specifically, the first clamping plate 41 has a first groove 401 at the end near the tilting table 5, and the second clamping plate 42 has a protrusion 402 at the end near the tilting table 5. The protrusion 402 is disposed in the first groove 401, and the pin 43 passes through the first groove 401 and the protrusion 402 vertically. 2. A cotter pin 44 is horizontally inserted through the lower end of the pin 43. One end of the connecting screw 45 is hinged to the end of the first clamping plate 41 away from the first groove 401, and the connecting screw 45 can be rotated horizontally. A hand-tightening nut 46 is screwed onto the end of the connecting screw 45 away from the first clamping plate 41. A second groove 403 is provided on the end of the second clamping plate 42 away from the protrusion 402. The connecting screw 45 is selectively inserted into the second groove 403. The cotter pin 44 is used to enclose the pin 43 on the clamp 4 to prevent it from falling off.

[0032] Clamp 4 is used to clamp the wheel hub axle. When clamping the wheel hub axle, loosen the hand-tightening nut 46, flip the connecting screw 45 horizontally to one side to move it out of the second groove 403, flip the second clamping plate 42 horizontally to one side to open it, then place the axle body of the wheel hub axle between the first clamping plate 41 and the second clamping plate 42, flip the second clamping plate 42 in the opposite direction to close it with the first clamping plate 41, flip the connecting screw 45 in the opposite direction to move it to the inside of the second groove 403, and tighten the hand-tightening nut 46 to clamp and fix the wheel hub axle between the first clamping plate 41 and the second clamping plate 42.

[0033] To accommodate wheel hub shafts of different thicknesses and to prevent damage to the wheel hub shafts, the clamp 4 also includes a copper pad 47. V-shaped grooves 404 are provided on the adjacent ends of the first clamping plate 41 and the second clamping plate 42. The copper pad 47 is fixed on the groove wall of each V-shaped groove 404. This structure forms a V-shaped clamping groove, which can accommodate wheel hub shafts of different thicknesses. Furthermore, the copper pad 47 protects the wheel hub shafts from damage.

[0034] The flipping platform 5 is located on the side of the support frame 2 and is fixedly mounted on the base 1. The upper end of the flipping platform 5 is positioned above the U-shaped opening 201 and can be flipped vertically, so that the upper end of the flipping platform 5 will not interfere with the installation of the wheel hub shaft. The positioning pin 6 is inserted through the upper end of the flipping platform 5. Specifically, the flipping platform 5 includes a column 51 and a positioning plate 52. The column 51 is fixedly mounted on the base 1, and the positioning plate 52 is hinged to the top of the column 51. The end of the positioning plate 52 away from the column 51 is provided with a through hole 501. The positioning pin 6 selectively passes through the through hole 501. The diameter of the positioning pin 6 is equal to the inner diameter of the through hole 501, so that the positioning pin 6 can be removed or inserted from the through hole 501. When positioning, the positioning pin 6 is inserted into the through hole 501. After positioning, the positioning pin 6 is pulled out from the through hole 501.

[0035] In the hinge structure of column 51 and positioning plate 52, column 51 and positioning plate 52 are rotatably hinged by damping shaft 53. The damping shaft 53 adopts a straight damping shaft with specification CL2020-0.3N, or other straight damping shafts can be used. The damping shaft 53 is set between column 51 and positioning plate 52. One end of the damping shaft 53 is fixedly connected to column 51, and the other end is fixedly connected to positioning plate 52. The rotation angle of positioning plate 52 can be flexibly set as needed through the damping shaft 53.

[0036] One end of the positioning pin 6 is conical and the other end is cylindrical. The conical part can be vertically inserted into the threaded hole on the end face of the hub shaft to hold the opening of the threaded hole. By holding, multiple threaded holes can be positioned alternately with greater precision, which facilitates the alignment of the tapping tool and the threaded hole to be processed, and makes it easier to process multiple threaded holes one by one, improving the tapping quality. It can also ensure the phase angle relationship between the tapped threaded hole and the smooth hole, ensuring the fit and connection of the hub shaft with other parts during subsequent assembly.

[0037] The above-mentioned wheel hub axle tapping fixture is used for Figure 9 The machining of the existing wheel hub shaft shown includes the following steps: The wheel hub shaft is clamped using a wheel hub shaft tapping fixture during machining. S1. Place the wheel hub axle tapping fixture on the tapping machine's worktable, align it, and then tighten it with bolts. S2. Prepare the wheel hub shaft to be processed. Open the clamp 4, put the shaft body of the wheel hub shaft into the U-shaped opening 201, and put the shaft body of the wheel hub shaft into the inside of the clamp 4. Then place the flange of the wheel hub shaft on the buffer assembly 3. The buffer assembly 3 will buffer the wheel hub shaft after it is placed. Then, the weight of the wheel hub shaft will press down on the buffer assembly 3, so that the top of the buffer assembly 3 is aligned with the top of the support frame 2. At this time, the wheel hub shaft is placed on the top of the support frame 2. S3. Rotate the hub shaft to roughly position it, close the clamp 4 but do not clamp it tightly, that is, insert the connecting screw 45 into the second groove 403, and tighten the hand nut 46 so that it abuts against the side end of the second clamping plate 42, but do not tighten it. S4. Flip the upper end of the flipping table 5 downwards, that is, flip the positioning plate 52, so that it is attached to the top surface of the wheel hub shaft. S5. Insert one conical end of the positioning pin 6 into the upper end of the tilting table 5 and move it downward so that one conical end of the positioning pin 6 is inserted into the threaded bottom hole at the end face of the wheel hub shaft and abuts against the opening of the threaded bottom hole. S6. Tighten the hand-tightening nut 46 to clamp the hub shaft body with the clamp 4, fix the hub shaft, and tap the threaded bottom hole at the diagonal hole of the positioning pin 6 with a tapping machine. S7. After machining is completed, remove the positioning pin 6, loosen the clamp 4, rotate the hub shaft, and machine the next threaded bottom hole; S8. Repeat steps S5-S7. After all machining is completed, remove the positioning pin 6, flip the top of the flip table 5 upwards to open it, then open the clamp 4, remove the wheel hub shaft, and the machining is finished.

[0038] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wheel hub axle tapping fixture, comprising a base (1), characterized in that: It also includes a support frame (2), a buffer assembly (3), a clamp (4), a tilting table (5), and a positioning pin (6), wherein, The support frame (2) is fixedly mounted vertically on the base (1) to support the flange bottom surface of the hub shaft; The buffer assembly (3) is detachably mounted on the top of the support frame (2) and can be elastically extended and retracted vertically at the top of the support frame (2) to elastically abut against the bottom surface of the flange of the hub shaft. The clamp (4) is fixedly installed on the side of the support frame (2) and is used to clamp the axle body of the hub shaft; The flipping platform (5) is located on the side of the support frame (2) and fixedly mounted on the base (1). The upper end of the flipping platform (5) is located above the buffer assembly (3) and can be flipped in the vertical direction. One end of the positioning pin (6) passes through the upper end of the flipping table (5) and is used to be inserted vertically into the threaded bottom hole at the end face of the wheel hub shaft; The buffer assembly (3) includes several supporting copper blocks (31), compression springs (32), guide rods (33), and limiting nuts (34), wherein, The support frame (2) has a U-shaped opening (201) on one side of its top, and the inner diameter of the U-shaped opening (201) is larger than the diameter of the wheel hub shaft. The top of the support frame (2) is provided with a plurality of storage slots (202), and the plurality of storage slots (202) are arranged in a circumferential ring array along the U-shaped opening (201); A number of the supporting copper blocks (31) are arranged in a number of the storage slots (202) in a one-to-one correspondence. The supporting copper blocks (31) and the corresponding storage slots (202) are slidably connected. The depth of the storage slots (202) is greater than the vertical thickness of the supporting copper blocks (31). Several compression springs (32) are provided in each of the storage slots (202). One end of the compression spring (32) abuts against the bottom of the storage slot (202), and the other end is fixedly connected to the bottom of the supporting copper block (31). The guide rod (33) passes vertically through the storage groove (202), the upper end of the guide rod (33) is screwed to the bottom of the supporting copper block (31), and the lower end of the guide rod (33) is screwed to the limiting nut (34). The limiting nut (34) is located outside the receiving groove (202).

2. The wheel hub axle tapping fixture as described in claim 1, characterized in that: One end of the positioning pin (6) is conical and the other end is cylindrical. The conical end of the positioning pin (6) selectively abuts against the threaded bottom hole at the end face of the wheel hub shaft.

3. The wheel hub axle tapping fixture as described in claim 2, characterized in that: The tilting table (5) includes a column (51) and a positioning plate (52), wherein, The column (51) is fixedly mounted on the base (1); The positioning plate (52) is hinged to the top of the column (51); The positioning plate (52) has a through hole (501) at one end away from the column (51). The positioning pin (6) selectively inserts into the through hole (501), and the diameter of the positioning pin (6) is equal to the inner diameter of the through hole (501).

4. The wheel hub axle tapping fixture as described in claim 3, characterized in that: The tilting table (5) also includes a damping shaft (53), wherein, The damping shaft (53) is disposed between the column (51) and the positioning plate (52); One end of the damping shaft (53) is fixedly connected to the column (51), and the other end is fixedly connected to the positioning plate (52).

5. The wheel hub axle tapping fixture as described in claim 4, characterized in that: The clamp (4) includes a first clamping plate (41) and a second clamping plate (42), wherein, The first clamping plate (41) is fixedly disposed on the side of the support frame (2); The second clamping plate (42) is disposed on the side of the first clamping plate (41) away from the support frame (2). One end of the first clamping plate (41) and the second clamping plate (42) are hinged together, and the other end is connected by bolts.

6. The wheel hub axle tapping fixture as described in claim 5, characterized in that: The clamp (4) also includes a pin (43) and a cotter pin (44), wherein, The first clamping plate (41) has a first groove (401) at one end near the flipping table (5). The second clamping plate (42) is provided with a protrusion (402) at one end near the flipping table (5), and the protrusion (402) is disposed in the first groove (401); The pin (43) passes through the first groove (401) and the protrusion (402) vertically. The cotter pin (44) is horizontally disposed at the lower end of the pin shaft (43).

7. A wheel hub axle tapping fixture as described in claim 6, characterized in that: The clamp (4) further includes a connecting screw (45) and a hand-tightening nut (46), wherein, One end of the connecting screw (45) is hinged to the end of the first clamping plate (41) away from the first groove (401), and the other end can be flipped in the horizontal direction; The hand-tightening nut (46) is screwed onto the end of the connecting screw (45) away from the first clamping plate (41); The second clamping plate (42) has a second groove (403) on one end away from the protrusion (402), and the connecting screw (45) is selectively fitted into the second groove (403).

8. A wheel hub axle tapping fixture as described in claim 7, characterized in that: The clamp (4) also includes a copper pad (47), wherein, V-shaped grooves (404) are provided on the adjacent ends of the first clamping plate (41) and the second clamping plate (42). The copper pad (47) is fixed at one point on the groove wall of each of the V-shaped grooves (404).

9. A method for machining a wheel hub shaft, characterized in that: The method of clamping the workpiece using the wheel hub tapping fixture as described in any one of claims 3-8 further includes the following steps: S1. Place the wheel hub shaft tapping fixture on the tapping machine's worktable, align it, and then tighten it with bolts. S2. Prepare the wheel hub shaft to be processed. Open the clamp (4), put the shaft body of the wheel hub shaft into the U-shaped opening (201), and put the shaft body of the wheel hub shaft into the inside of the clamp (4). Then place the flange of the wheel hub shaft on the buffer assembly (3). The buffer assembly (3) buffers the wheel hub shaft after it is placed. Then, the wheel hub shaft presses down on the buffer assembly (3) by its own weight, so that the top of the buffer assembly (3) is aligned with the top of the support frame (2). At this time, the wheel hub shaft is placed on the top of the support frame (2). S3. Rotate the hub shaft to roughly position it, and close the clamp (4) but do not clamp it tightly; S4. Flip the upper end of the flipping table (5) downwards so that it is pressed against the top surface of the hub shaft; S5. Insert one conical end of the positioning pin (6) into the upper end of the flipping table (5) and move it downward so that one conical end of the positioning pin (6) is inserted into the threaded bottom hole at the end face of the wheel hub shaft and abuts against the opening of the threaded bottom hole. S6. Clamp the hub shaft with the clamp (4) to fix the hub shaft, and tap the threaded bottom hole at the diagonal hole of the positioning pin (6) with the tapping machine. S7. After processing, remove the positioning pin (6), loosen the clamp (4), rotate the hub shaft, and process the next threaded bottom hole; S8. Repeat steps S5-S7. After all processing is completed, remove the positioning pin (6), flip the upper end of the flipping table (5) upward to open it, then open the clamp (4), remove the wheel hub shaft, and the processing is finished.

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