Half axle sleeve multi-step precision turning positioning device and method

Abstract

The application discloses a semi-axle sleeve multi-step precision turning positioning device and method, and relates to the technical field of semi-axle sleeve turning processing tooling. The existing semi-axle sleeve turning tooling can only single-clamp the big head or the small head of a workpiece, and the workpiece needs to be replaced with tooling when clamped in positive or reverse directions. The positioning reference switching is complicated, the coaxiality is poor, the multi-step processing size precision is unstable, the clamping and pressing mechanism is separated, the single clamping rigidity is insufficient, and the tool is prone to shaking. The device comprises a lathe supporting chuck, synchronous radial motion claws, a built-in bevel gear-spool transmission mechanism and an axial through guide pillar pressing assembly. The claws are provided with double-step clamping surfaces, and can respectively adapt to the big head / small head of the semi-axle sleeve in two clamping conditions of internal expansion and external clamping. The machine tool thimble drives the top block cone to open multiple sets of pressing claws to realize axial pressing of the workpiece, and the reset spring and the compression spring realize automatic reset of the mechanism. The application completes the positive and reverse clamping of the semi-axle sleeve with one set of tooling, and the clamp does not need to be replaced.

Description

Technical Field

[0001] This invention belongs to the field of precision turning tooling technology for shaft and tube fittings, specifically relating to a multi-step precision turning positioning device and matching positioning machining method for axle sleeves, which is applicable to CNC precision turning of the multi-step outer circle, inner hole and end face of both ends of automotive axle sleeves. Background Technology

[0002] The automotive half-shaft sleeve is a typical multi-step tubular part, with a large-diameter flange at one end and a slender small-diameter end at the other. The workpiece has multiple steps distributed inside and outside. Turning requires two working conditions: Working condition 1, clamping with the large end facing down, turning the outer diameter, inner hole and end face of the small end; Working condition 2, clamping the workpiece upside down with the small end facing down, turning the large end flange, the inner hole of the large end and the inner lining steps.

[0003] Existing similar turning positioning fixtures have the following defects: 1. The tooling clamping mode is limited. The internal support tooling is only suitable for large-end clamping, and the external clamping tooling is only suitable for small-end clamping. Two sets of clamps need to be changed for processing two different working conditions, which is time-consuming and results in low changeover efficiency for mass production. 2. The centering and axial clamping mechanisms are independent of each other. First, the radial jaws are used for centering, and then the tailstock center is used alone to clamp the end face of the workpiece. The two locking points are not synchronized. During the machining process, the workpiece is prone to axial movement and radial slight offset. The coaxiality and end face runout of multi-step turning are out of tolerance. 3. Compare the shortcomings of existing patented tooling: (1) CN215788272U bearing inner diameter turning positioning device: It adopts bolt single-point positioning combined with side pressure plate clamping, which is only suitable for positioning of small bearing single pieces. It does not have a synchronous centering chuck structure, cannot be adapted to long tubular half shaft sleeves, and does not support forward and reverse bidirectional clamping. (2) CN220971464U ball screw nut turning positioning device: It only uses the outer peripheral fixed arc claw to clamp the outer circle of the workpiece, without an inner support clamping structure, and only a single clamping mode, which cannot complete the inner support clamping of the big end of the half shaft sleeve. (3) CN220006025U planetary gear support turning positioning device: It relies on the combination of motor, electric push rod and electromagnet to adjust the clamping. It has a complex structure and high cost. It does not have an integrated structure of lathe chuck, and cannot directly install CNC lathe spindle. It is not suitable for turning rotary pipe fittings.

[0004] In summary, there is an urgent need for an integrated, dual-mode clamping, synchronous centering and clamping, and automatic reset multi-step turning positioning device for half-shaft sleeves. One set of tooling can complete both forward and reverse clamping of the workpiece, thereby improving the machining accuracy and production efficiency of multi-step machining. Summary of the Invention

[0005] To address the shortcomings of existing tooling technologies, such as limited clamping modes, cumbersome tooling changes, asynchronous centering and clamping, poor machining accuracy, and inability to adapt to automated mass production, this invention provides a multi-step precision turning positioning device and method for axle sleeves. This device enables a single tooling unit to complete two clamping conditions: internal support at the large end and external clamping at the small end of the axle sleeve. The chucks provide synchronous radial centering, which is combined with the tailstock pin linkage for synchronous axial clamping. The mechanism features an integrated spring for automatic reset, reducing workpiece clamping deformation and improving the dimensional accuracy of multi-step turning and the automation level of loading and unloading.

[0006] Option 1: A multi-step precision turning positioning device for a half-shaft sleeve includes a chuck, multiple sets of jaws, a transmission mechanism, a guide post, a linear bearing, a return spring, a top block, multiple sets of pressure jaws, and a pressure cover. The chuck is fixedly installed on the spindle end of a CNC turning machine tool. The chuck includes a disc body and a sealed disc cover, and the disc cover has a radial guide groove. Multiple sets of jaws are arranged radially at equal intervals along the circumference of the chuck and are slidably assembled in the guide groove. The transmission mechanism is integrated into the annular cavity inside the disc body and is used to synchronously drive all the claws to expand / contract radially. The guide post passes through the chuck along the central axis of the chuck, and a linear bearing is fixed at the bottom of the chuck, which slides and guides the guide post. The reset spring is coaxially sleeved on the outside of the guide post. One end of the reset spring abuts against the inner end face of the disc and the other end abuts against the middle step surface of the guide post. Under normal conditions, it provides an upward push-out preload force to the guide post. The pressure cap is locked and fixed to the top end face of the guide post. The pressure cap is hollow inside and a top block is slidably assembled. The upper end of the top block extends out of the pressure cap and corresponds to the top pin of the machine tool tailstock. The lower end of the top block is integrally formed into a cone. Multiple sets of pressure claws are arranged radially at equal intervals along the top circumference of the pressure cap. A tapered surface is opened in the middle of the pressure claw to fit against the inclined surface of the tapered body at the lower end of the top block. A claw head is set at the bottom of the outer end of the pressure claw to press the end face / inner liner step of the half shaft sleeve. Multiple limiting posts are integrally formed on the inner side of the bottom of the pressure cap. Each limiting post is fitted with a compression spring on the outside. One end of a single compression spring abuts against the inner wall of the pressure cap, and the other end abuts against the corresponding pressure claw. Under normal conditions, the compression spring drives all the pressure claws to retract towards the center of the pressure cap. The claw includes a slide and a detachable clamping block. The bottom surface of the slide has a groove that matches the spiral guide bar of the transmission mechanism. The clamping block is integrally formed with a first step surface and a second step surface. The first step surface is used to support the inner wall of the large diameter of the half-shaft sleeve from the inside out, and the second step surface is used to clamp the outer circle of the small end of the half-shaft sleeve from the outside in. Limiting posts are provided on both sides of the second step surface. The transmission mechanism includes a wire disc, a spiral guide bar, a beveled toothed ring, and multiple sets of bevel gears. A convex ring is coaxially arranged on the inner side of the disc, and an annular cavity is formed on the outer periphery of the convex ring for mounting the wire disc. A spiral guide bar is arranged in an annular pattern on the top surface of the wire disc, and a beveled toothed ring is integrally formed on the bottom surface of the wire disc. Multiple sets of bevel gears are equidistantly mounted in an annular pattern on the disc. The bevel gears mesh with the beveled toothed ring, and the external drive bevel gears rotate to drive the wire disc to rotate circumferentially. The spiral guide bar drives all the chucks to move radially synchronously.

[0007] Furthermore, a limiting groove is provided on the top of the pressure claw, and the limiting groove slides in conjunction with the side wall of the pressure cover to limit the radial sliding stroke of the pressure claw and prevent the pressure claw from completely dislodging from the pressure cover.

[0008] Furthermore, the number of jaws and pressure jaws are both 3 sets, evenly distributed at 120° angles along the center of the chuck to ensure uniform force distribution around the workpiece.

[0009] Furthermore, the linear bearing is a copper-based oil-impregnated linear sliding bearing, which is bolted to the bottom of the disc to reduce the axial sliding friction resistance of the guide post.

[0010] Furthermore, the disc cover is locked and fixed to the upper end face of the disc body by internal hex bolts, and the guide groove is opened on the surface of the disc cover and is in clearance fit with the claw slide seat to accurately guide the radial sliding of the claw.

[0011] Furthermore, the top block and the center hole of the pressure cap are slidably fitted with a gap, and the upper end of the top block is chamfered to facilitate the precise centering and pressing of the tailstock ejector pin.

[0012] Option 2: A method for positioning a multi-step precision turning of a half-shaft sleeve, using the above-mentioned multi-step precision turning and positioning device for a half-shaft sleeve, includes a turning process with the large end facing down and a turning process with the small end facing down and an inverted turning process. Step 1: Pre-assembly and debugging of tooling Fix the chuck to the CNC lathe spindle flange and complete the spindle coaxiality correction; adjust the external drive knob of the bevel gear of the transmission mechanism to confirm that the three sets of jaws expand and contract synchronously without jamming; check that the guide post and top block slide smoothly, the return spring and compression spring have normal elasticity, and the jaws can automatically retract and reset to the center.

[0013] Step 2: Clamp the half-shaft sleeve with the large end facing down (turn the small end side to create multiple steps). S201 Workpiece Placement: Place the half-shaft sleeve with the large end facing down and the small end facing up, and hoist it between the three sets of jaws. The inner wall of the large diameter of the half-shaft sleeve should correspond to the first step surface of the jaws. S202 Radial Inner Support Centering: Rotating the external drive knob drives the bevel gear to mesh with the inclined gear ring to drive the screw spool to rotate. The spiral guide bar pushes the three sets of jaws to expand radially outward in sync. The first step surface fits against the inner wall of the big end of the half shaft sleeve, and the workpiece is supported from the inside out to complete the radial centering. S203 Axial Synchronous Clamping: The tailstock ejector pin of the machine tool moves forward to press the upper end of the ejector block. The ejector block slides down along the pressure cover. The lower end cone squeezes the conical surface of the three sets of clamping claws, overcoming the spring force of the compression spring and driving the clamping claws to extend radially outward synchronously. The claw head presses down and fits against the top edge of the upper end of the half-shaft sleeve, completing the axial locking of the workpiece and eliminating the axial movement of the workpiece. S204 Turning: Start the lathe spindle to rotate and turn the outer diameter of the small end of the half-shaft sleeve, the multi-step, and the small end face in sequence; S205 Unloading: The tailstock ejector pin retracts and disengages from the top block, and the compression spring pulls the gripper to retract and reset towards the center; the reverse rotation of the drive knob causes the gripper to synchronously retract radially inward to loosen the inner wall of the large head, and the robot arm grabs the workpiece for unloading.

[0014] Step 3: Clamp the half-shaft sleeve with the small end facing down (turn the large end side to create multiple steps). S301 Workpiece inverted placement: After machining the small end, flip the half-shaft sleeve with the small end facing down and the large end facing up, and place it between the three sets of jaws. The outer circle of the small end of the half-shaft sleeve corresponds to the second step surface of the jaws, and the two side jaw posts limit the radial offset of the workpiece. S302 Radial External Clamping Centering: Reverse rotation of the drive knob causes the spool to drive the three sets of jaws to retract radially inward in sync. The second step surface clamps the outer circle of the small end of the half-shaft sleeve from the outside to the inside, completing the radial centering of the inverted workpiece. S303 Axial Synchronous Clamping: The tailstock ejector pin feeds the top block again, the cone opens the clamping claws to extend radially, and the claw heads press down to fit the inner lining step of the half-shaft sleeve, thus achieving axial clamping of the inverted workpiece. S304 Turning: Spindle rotation, turning the outer diameter of the large end flange of the half-shaft sleeve, the multi-stage steps of the large end, the inner hole of the large end, and the stepped end face of the inner lining; S305 Finished Product Unloading: The tailstock ejector pin retracts, the pressure claw automatically retracts, and the chuck expands outwards synchronously to loosen the outer diameter of the small end, thus removing the finished workpiece.

[0015] Step 4: Repeat steps 2 and 3 in a continuous batch processing cycle to complete the multi-step turning of both ends of the batch half-shaft sleeves. No tooling components need to be changed during the processing.

[0016] Compared with related technologies, the multi-step precision turning positioning device and method for axle sleeve provided by the present invention has the following beneficial effects: 1. Dual-mode integrated clamping, one set of tooling for two uses. The jaws integrate the first and second step clamping surfaces, which are adapted to two working conditions: large end internal support and small end external clamping. The workpiece can be clamped in both directions without changing the fixture, saving the time of changing and disassembling the tooling. The changeover efficiency for mass production is improved by more than 60%. Compared with the existing two separate tooling sets, the equipment purchase and storage costs are greatly reduced.

[0017] 2. Fully synchronous centering and clamping significantly improves machining accuracy. It adopts a bevel gear-sloping gear ring-screw spiral synchronous transmission structure. The three sets of jaws move radially synchronously at 120°, and the clamping force is uniform. There is no local clamping deformation of the thin-walled half shaft sleeve. The tailstock ejector pin and the ejector block synchronously open all the clamping jaws. Radial centering and axial clamping are completed simultaneously, eliminating the axial movement and radial slight deviation of the workpiece. The coaxiality of the multi-step outer circle and the end face runout are controlled within 0.005mm, and the dimensional consistency is greatly improved.

[0018] 3. Spring-linked automatic reset, suitable for automated production lines. The reset spring controls the guide post to rise normally, the pressure spring to retract the pressure claw normally, and the pressure claw automatically retracts after the tailstock ejector pin retracts and the chuck is released, allowing the robot arm to load and unload directly without the need for manual disassembly of the clamping components. It can be connected to the automatic loading and unloading mechanism of CNC lathes to achieve unmanned continuous processing.

[0019] 4. High structural integration and strong versatility: The chuck, centering transmission, and axial clamping components are integrated into one unit, directly adapting to standard CNC lathe spindles; the jaw blocks are detachable and replaceable, adapting to different pipe diameter series of half-shaft sleeves, resulting in strong tooling versatility; guide grooves and linear bearing sliding pairs reduce motion wear, extending tooling service life.

[0020] 5. This invention relies on the integrated structure of the lathe spindle chuck, which has stronger rotational clamping rigidity. It also has a dual clamping mode of internal support and external clamping. The synchronous centering and clamping mechanism is simplified, and there are no additional electrical control components such as motors and electromagnets. It has a low failure rate and is easy to maintain. It is more suitable for mass production of multi-step precision turning of long tubular half-shaft sleeves. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a multi-step precision turning and positioning device for a half-shaft sleeve proposed in this invention applied to working condition 1; Figure 2 This is a schematic diagram of a cross section of a multi-step precision turning and positioning device for a half-shaft sleeve proposed in this invention, applied to working condition 1. Figure 3 This is a schematic diagram of the application of the multi-step precision turning and positioning device for a half-shaft sleeve proposed in this invention to working condition 2; Figure 4 This is a schematic diagram of the cross section of a multi-step precision turning and positioning device for a half-shaft sleeve proposed in this invention, applied to working condition 2. Figure 5 for Figure 2 Enlarged view of point A in the middle; Figure 6 This is a schematic diagram of the chuck and transmission mechanism proposed in this invention; Figure 7 This is a schematic diagram of the guide post, top block, and pressure claw proposed in this invention.

[0022] In the diagram: 1. Chuck; 11. Chuck body; 12. Chuck cover; 13. Convex ring; 14. Guide groove; 2. Chuck claw; 21. Slide block; 22. Clamping block; 23. Chuck groove; 24. First step surface; 25. Second step surface; 26. Chuck post; 3. Transmission mechanism; 31. Threaded spool; 32. Helical guide bar; 33. Inclined gear ring; 34. Bevel gear; 4. Guide post; 5. Linear bearing; 6. Return spring; 7. Top block; 71. Cone; 8. Pressure claw; 81. Claw head; 82. Conical surface; 83. Limiting groove; 84. Compression spring; 9. Pressure cover; 91. Limiting post. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can understand it.

[0024] Example 1: Precision Turning Positioning Device for Half-Shaft Sleeves like Figures 1-7 As shown, a multi-step precision turning positioning device for a half-shaft sleeve includes a chuck 1, three sets of jaws 2, a transmission mechanism 3, a guide post 4, a linear bearing 5, a return spring 6, a top block 7, three sets of pressure jaws 8, and a pressure cover 9.

[0025] The chuck 1 is composed of a disc body 11 and a disc cover 12 bolted together. The disc body 11 is bolted to the spindle of the CNC lathe. Three radially penetrating guide grooves 14 are opened on the surface of the disc cover 12, and the three guide grooves 14 are evenly distributed at 120°. Three sets of jaws 2 are slidably assembled inside the three guide grooves 14. The jaws 2 are bolted to the slide 21 and the detachable clamping block 22. An arc-shaped chuck groove 23 is opened on the bottom surface of the slide 21. The outer side of the clamping block 22 is integrally formed with a first stepped surface 24 (inner support clamping surface), and the inner side of the clamping block 22 is integrally formed with a second stepped surface 25 (outer clamping surface). Cylindrical chuck posts 26 are symmetrically arranged on the left and right sides of the second stepped surface 25. When clamped upside down, the chuck posts 26 fit against the small end face of the half-shaft sleeve to limit the movement and prevent the workpiece from sliding axially.

[0026] The transmission mechanism 3 is entirely built into the annular cavity inside the disc body 11. The disc body 11 has a centrally formed convex ring 13, and the outer ring of the convex ring 13 forms an annular mounting cavity for assembling the wire spool 31. The top surface of the wire spool 31 is continuously arranged with spiral guide bars 32, which precisely mesh with the bottom groove 23 of the slide block 21. The bottom surface of the wire spool 31 is integrally cast with a beveled toothed ring 33. The disc body 11 is equidistantly mounted with three sets of bevel gears 34. The outer ends of the bevel gears 34 extend to the outside of the disc body and are equipped with adjustment knobs or connected drive devices. The teeth of the bevel gears 34 are fully meshed with the beveled toothed ring 33. Rotating the external adjustment knob drives the bevel gears 34 to rotate, and the meshing with the beveled toothed ring 33 drives the wire spool 31 to rotate circumferentially. The spiral guide bars 32 synchronously pull the three sets of jaws 2 to expand or contract radially, thereby achieving workpiece centering.

[0027] The guide post 4 is assembled through the central axis of the chuck 1. The bottom of the disc body 11 is fixed with a linear bearing 5 by bolts. The linear bearing 5 is sleeved on the outer wall of the guide post 4 to achieve low-resistance axial sliding of the guide post 4. The return spring 6 is coaxially sleeved on the outside of the guide post 4. The lower end of the return spring 6 abuts against the inner bottom surface of the disc body 11, and the upper end abuts against the annular step surface in the middle of the guide post 4. When there is no external force pressing, the return spring 6 continuously pushes the guide post 4 upward, so that the guide post 4 keeps the top end raised.

[0028] The top of the guide post 4 is fixed to the pressure cap 9 by a locking bolt. An axial through hole is opened in the center of the pressure cap 9, and the top block 7 is slidably assembled in the through hole with clearance. The upper end of the top block 7 extends out of the top surface of the pressure cap 9, and a 45° guide chamfer is set at the top end to facilitate precise centering of the lathe tailstock center. The lower end of the top block 7 has an integral conical cone 71, and the outer diameter of the cone 71 gradually decreases downward. Three sets of pressure claws 8 are evenly arranged along the circumference of the top of the pressure cap 9 at 120°. A conical surface 82 is opened on the inner side of each pressure claw 8, and the slope angle of the conical surface 82 is perfectly matched with the taper of the cone 71. The bottom of the outer end of the pressure claw 8 extends downward to form a claw head 81, which is used to press the upper end face of the half-shaft sleeve or the inner lining step. A long strip limiting groove 83 is opened on the top of the pressure claw 8. The limiting groove 83 slides with the boss on the side wall of the pressure cap 9 to limit the maximum radial extension stroke of the pressure claw and prevent the pressure claw from completely disengaging. Three limiting posts 91 are integrally formed radially on the inner side of the bottom of the pressure cap 9, and the limiting posts 91 correspond to three sets of pressure claws 8 respectively; a pressure spring 84 is fitted on the outside of each limiting post 91, one end of the pressure spring 84 abuts against the inner wall of the pressure cap 9, and the other end abuts against the inner end face of the corresponding pressure claw 8; when no top block is pressed down, the pressure spring 84 continuously pushes the pressure claw 8 inward, and the three sets of pressure claws automatically retract and reset towards the center of the pressure cap.

[0029] Example 2: Precision Turning and Positioning Machining Method for Half-Shaft Sleeves with Multiple Steps Using the positioning device described in Example 1, the processing is divided into two main conditions, and the complete processing flow is as follows: I. Preliminary calibration and debugging of tooling 1. Place chuck 1 against the end face of the CNC lathe spindle and tighten it evenly with locking bolts. Use a dial indicator to check that the runout of the chuck end face is ≤0.002mm, ensuring that the tooling is coaxial with the spindle; 2. Rotate the outer adjustment knob of the bevel gear 34 and observe the three sets of pawls 2 expanding and contracting synchronously without jamming or unilateral deviation; 3. Manually press down the top block 7, and the cone 71 will simultaneously open the three sets of pressure claws 8. After releasing the top block 7, the pressure spring 84 will pull the pressure claws 8 to automatically retract. Release the guide post 4, and the reset spring 6 will push the guide post 4 upward. The sliding is unobstructed, confirming that the spring force meets the usage requirements. 4. According to the diameter specification of the half-shaft sleeve to be processed, replace the clamping block 22 with one of appropriate thickness to ensure that the first step surface 24 and the second step surface 25 are completely in contact with the outer / inner wall of the workpiece.

[0030] II. Working Condition 1: The half-shaft sleeve is clamped with the large end facing down, and the small end side is machined with multiple steps. Figure 1 , Figure 2 ) 1. Workpiece loading: The robot arm grabs the half-shaft sleeve workpiece 10 with the large end facing down and the small end facing up. The large end of the workpiece is inserted into the middle of the three sets of jaws 2, so that the inner wall of the large end is in contact with the first step surface 24 of the clamping block 22.

[0031] 2. Synchronous radial inner support: Rotate the bevel gear 34 adjustment knob clockwise for centering. The bevel gear 34 meshes with the inclined gear ring 33, which drives the screw spool 31 to rotate circumferentially. The spiral guide bar 32 pushes the three sets of jaws 2 to expand radially outward in sync. The first step surface 24 evenly fits against the inner wall of the large end of the half-shaft sleeve, supporting the workpiece from the inside out and completing radial centering. The synchronous movement of the jaws ensures that the center of the workpiece is completely aligned with the axis of the main spindle.

[0032] 3. Tailstock linkage axial clamping: The tailstock of the CNC lathe drives the ejector pin to feed forward axially. The top of the ejector pin fits against the chamfer of the upper inner hole of the ejector block 7 and continues to press downward. The ejector block 7 slides downward along the center hole of the pressure cover 9. The lower cone 71 presses down on the conical surface 82 of the three sets of clamping claws 8, overcoming the elastic force of the compression spring 84 and driving the three sets of clamping claws 8 to extend radially outward in sync. The claw head 81 presses down and fits against the top edge of the small end of the half shaft sleeve, pressing the workpiece axially on the clamping surface of the chuck, completely eliminating the axial clearance and movement of the workpiece.

[0033] 4. Multi-step turning: Lock the tailstock position, start the lathe spindle rotation, and the CNC program completes the following steps in sequence: rough turning of the small end outer diameter, finish turning of the small end multi-step, and turning of the small end end face. All multi-step machining of the small end side is completed in one setup.

[0034] 5. Automatic unloading: After processing, the tailstock drives the ejector pin to retract, the ejector pin disengages from the top block 7, the compression spring 84 pulls the three sets of pressure claws 8 to retract inward synchronously, the claw head 81 lifts up and releases the upper end face of the workpiece; rotate the adjustment knob counterclockwise, the screw spool 31 drives the chuck 2 to retract inward synchronously, the first step surface 24 disengages from the inner wall of the big head, and the robot directly grabs the processed half shaft sleeve for unloading.

[0035] III. Working Condition 2: The half-shaft sleeve is clamped with the small end facing down, and the large end side is machined with multiple steps. Figure 3 , Figure 4 ) 1. Workpiece inverted loading: The robot arm rotates the half-shaft sleeve with the small end processed by 180°, with the small end vertically downward and the large end upward. The small end is placed between the three sets of jaws 2, with the outer circle of the small end aligned with the second step surface 25 of the clamping block 22, and the two side clamping posts 26 are attached to the lower end surface of the small end for auxiliary positioning.

[0036] 2. The bevel gear 34 is adjusted by rotating the adjustment knob counterclockwise to synchronously rotate the radial outer clamping centering. The screw spool 31 drives the three sets of jaws 2 to synchronously retract radially inward. The second step surface 25 clamps the outer circle of the small end of the half-shaft sleeve from the outside to the inside. The clamping post 26 restricts the micro-movement of the workpiece, thus completing the radial centering of the inverted workpiece.

[0037] 3. Axial synchronous clamping of the inner liner step: The tailstock ejector pin moves forward again to press the ejector block 7, the cone 71 opens and the three sets of clamping claws 8 extend radially, the claw head 81 presses down and extends into the half shaft sleeve to clamp the inner liner step of the workpiece, realizing bidirectional locking of the inverted workpiece and eliminating processing vibration.

[0038] 4. Multi-step turning of the large end: The spindle rotates and the CNC program processes the outer diameter of the large end flange, the multi-step of the large end flange, the inner hole of the large end flange, and the end face of the inner lining step, completing all multi-step machining of the workpiece.

[0039] 5. Finished product unloading: The tailstock ejector pin retracts, and the pressure claw 8 automatically retracts and lifts; rotate the adjustment knob clockwise, and the chuck 2 expands outward to loosen the outer diameter of the small end. The robot arm takes out the finished half-shaft sleeve and enters the next cycle of processing.

[0040] IV. Batch Continuous Processing The entire process of repeating working conditions 1 and 2 is completed. The entire batch of half-shaft sleeves is processed without disassembling or replacing any tooling components. The expansion / contraction state of the chuck is switched by rotating the adjustment knob, which realizes the quick switching between the two clamping modes of internal support and external clamping, and is suitable for continuous and uninterrupted production on automated production lines.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A multi-step precision turning and positioning device for a half-shaft sleeve, characterized in that: Includes chuck (1), multiple sets of jaws (2), transmission mechanism (3), guide post (4), linear bearing (5), return spring (6), top block (7), multiple sets of pressure jaws (8), and pressure cap (9); The chuck (1) is mounted on the spindle of a turning machine tool. The chuck (1) includes a disc body (11) and a disc cover (12). The disc cover (12) has a radial guide groove (14). Multiple sets of jaws (2) are arranged radially at equal intervals along the circumference of the chuck (1) and are slidably assembled in the guide groove (14). The transmission mechanism (3) is integrated into the annular cavity inside the disc body (11) and is used to synchronously drive all jaws (2) to synchronously expand or contract radially. The guide post (4) passes through the chuck (1) along the central axis of the chuck (1). A linear bearing (5) is fixed at the bottom of the chuck (1), and the linear bearing (5) slides and guides the guide post (4). The return spring (6) is coaxially sleeved on the outside of the guide post (4). One end of the return spring (6) abuts against the disc body (11), and the other end abuts against the middle step surface of the guide post (4). Under normal conditions, it provides an upward preload force to the guide post (4). The pressure cap (9) is fixed to the top of the guide post (4). The top block (7) is slidably assembled inside the pressure cap (9). The upper end of the top block (7) extends out of the pressure cap (9) to match the tailstock ejector pin of the machine tool. The lower end of the top block (7) is provided with a cone (71). Multiple sets of pressure claws (8) are arranged radially at equal intervals along the top circumference of the pressure cover (9). The pressure claws (8) are provided with a conical surface (82) that matches the cone (71). The bottom of the outer end of the pressure claws (8) is provided with a claw head (81) for pressing the end face of the half-shaft sleeve or the inner lining step. The bottom inner side of the pressure cover (9) is provided with a limiting post (91). The limiting post (91) is covered with a compression spring (84). The two ends of the compression spring (84) abut against the pressure cover (9) and the pressure claws (8) respectively. Under normal conditions, the compression spring (84) drives the pressure claws (8) to retract toward the center of the pressure cover (9).

2. The multi-step precision turning and positioning device for a half-shaft sleeve according to claim 1, characterized in that: The claw (2) includes a slide (21) and a clamping block (22). The bottom surface of the slide (21) is provided with a groove (23). The clamping block (22) is fixed to the slide (21). The clamping block (22) is provided with a first stepped surface (24) for supporting the large end of the half-shaft sleeve from the inside out and a second stepped surface (25) for clamping the small end of the half-shaft sleeve from the outside in. The second stepped surface (25) is provided with clamping posts (26) on both sides.

3. The multi-step precision turning positioning device for a half-shaft sleeve according to claim 1, characterized in that: The transmission mechanism (3) includes a wire disc (31), a spiral guide bar (32), a bevel gear ring (33), and multiple sets of bevel gears (34). A convex ring (13) is coaxially provided on the inner side of the disc body (11), and an annular cavity is formed around the convex ring (13) for assembling the wire disc (31). The top surface of the wire disc (31) is provided with a spiral guide bar (32), and the bottom surface is provided with a bevel gear ring (33). The disc body (11) rotates annularly at equal intervals to assemble the bevel gears (34). The bevel gears (34) mesh with the bevel gear ring (33), and the bevel gears (34) drive the wire disc (31) to rotate circumferentially. The spiral guide bar (32) synchronously drives all the pawls (2) to move radially.

4. The multi-step precision turning positioning device for a half-shaft sleeve according to claim 1, characterized in that: The pressure claw (8) has a limiting groove (83) on its top. The limiting groove (83) slides with the side wall of the pressure cap (9) to limit the maximum radial sliding stroke of the pressure claw (8).

5. The multi-step precision turning positioning device for a half-shaft sleeve according to claim 1, characterized in that: The number of the chuck (2) and the pressure claw (8) are both 3 sets, and they are evenly distributed at an angle of 120° along the center of the chuck (1).

6. The multi-step precision turning and positioning device for a half-shaft sleeve according to claim 1, characterized in that: The linear bearing (5) is bolted to the bottom of the disc (11), and the linear bearing (5) is a copper-based oil-impregnated sliding bearing.

7. A method for precision machining and positioning of a half-shaft sleeve using multi-step machining, characterized in that: The multi-step precision turning and positioning device for the axle sleeve according to any one of claims 1-6 includes a turning process with the large end facing down and a turning process with the small end facing down and an inverted turning process. The specific steps are as follows: S1 tooling pre-installation and debugging: Fix the chuck (1) to the lathe spindle and correct the coaxiality. Debug the transmission mechanism (3), guide column (4), top block (7), and pressure claw (8) to ensure smooth movement and normal spring return. S2 half-shaft sleeve clamped with the large end facing down for machining: S201 Workpiece placement: The half-shaft sleeve is placed between the jaws (2) with the large end facing down and the small end facing up, and the inner wall of the large end corresponds to the first step surface (24) of the jaws. S202 Radial inner support centering: The drive transmission mechanism (3) drives the pawl (2) to expand radially outward in sync, and the first step surface (24) supports the inner wall of the big end of the half shaft sleeve to complete the centering; S203 Axial Synchronous Clamping: The tailstock ejector pin presses against the ejector block (7), the lower end cone (71) of the ejector block (7) squeezes the conical surface (82) of the clamping claw (8), driving the clamping claw (8) to extend outward synchronously, and the claw head (81) presses against the top edge of the upper end of the half-shaft sleeve; S204 turning process: spindle rotation, turning the small end side of the half-shaft sleeve with multiple steps; S205 Unloading: The tailstock ejector pin retracts, the compression spring (84) drives the pressure claw (8) to automatically retract, the chuck (2) retracts synchronously to release the workpiece, and the robot unloads the material; S3 half-shaft sleeve is clamped and machined with the small end facing down: S301 Workpiece inverted position: Flip the half shaft sleeve, with the small end down and the large end up between the jaws (2), and the outer circle of the small end corresponds to the second step surface (25) of the jaws (2). S302 Radial outer clamping centering: Reverse drive transmission mechanism (3), pawl (2) synchronously radially retracts inward, second step surface (25) clamps the outer circle of the small end of the half shaft sleeve to complete centering; S303 Axial Synchronous Clamping: The tailstock ejector pin presses against the top block (7) to open the clamping claw (8), and the claw head (81) presses down to clamp the step of the inner lining of the half-shaft sleeve; S304 Turning: Spindle rotation, turning the entire large end side of the half-shaft sleeve with multiple steps; S305 Finished product unloading: The tailstock ejector pin retracts, the pressure claw (8) automatically retracts, the chuck (2) expands to release the workpiece, and the finished product is taken out; S4 Batch Cycle: Repeat steps S2 and S3 to complete the multi-step turning of both ends of the batch half-shaft sleeves, without the need to change tooling components throughout the process.

8. The method for multi-step precision turning and positioning of a half-shaft sleeve according to claim 7, characterized in that: In steps S202 and S302, the screw spool (3) is driven to rotate by adjusting the knob on the outside of the rotating bevel gear (34), and the spiral guide bar (32) synchronously drives the three sets of jaws (2) to expand or contract synchronously, so as to ensure that the workpiece is circumferentially centered and subjected to uniform force without clamping deformation.

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