A fixture for machining a shaft workpiece

Abstract

The present application relates to a kind of clamps for shaft workpiece machining, including chuck and the clamping jaw of being clamped to shaft workpiece;It further includes follow-up block, transmission unit and locking unit;Follow-up block is set in the side of clamping jaw and along the axial direction of chuck through chuck;Transmission unit is set in the side of chuck away from clamping jaw and is connected with follow-up block, transmission unit includes the limit block of moving along the axial direction of chuck, is set in the inclined slot of limit block, the side of follow-up block extends to inclined slot;Locking unit is set in the side of limit block, locking unit is used to lock limit block, locking unit includes extrusion rod and pressure sensor, extrusion rod is set in the side of limit block away from chuck along the direction of limit block movement, pressure sensor is set in the end of limit block towards extrusion rod.The present application both ensures the clamping stability when hard shaft workpiece is processed, and avoids the surface damage of soft shaft workpiece due to overpressure.

Description

Technical Field

[0001] This invention relates to the field of fixtures, and more specifically to a fixture for machining shaft workpieces. Background Technology

[0002] When machining shaft workpieces, a special fixture for shaft workpiece machining is required. The main fixture for shaft workpiece machining is a three-jaw chuck. The three-jaw chuck mainly adopts a mechanical self-clamping type. During the machining process, the three-jaw chuck will rotate, causing the jaws on the three-jaw chuck to be subjected to a large centrifugal force. After long-term use, the clamping will become loose. The existing improvement method is to convert the centrifugal force into pre-clamping force after the three-jaw chuck rotates. However, it cannot be combined with the existing mechanical self-clamping structure, resulting in insufficient clamping force at low speeds.

[0003] Chinese invention patent application (publication number CN120394933A) discloses a CNC lathe shaft workpiece machining fixture, including a three-jaw chuck. The three-jaw chuck includes a chuck body, a large bevel gear, a small bevel gear, jaws, and an auxiliary clamping device. The auxiliary clamping device includes: an auxiliary bevel gear rotatably disposed in the chuck body and coaxially arranged with the large bevel gear, and meshing with at least one of the small bevel gears; a centrifugal block slidably disposed in the chuck body along the radial direction, the centrifugal block being able to generate centrifugal displacement with the rotation of the chuck body; and a transmission assembly disposed in the chuck body and connecting the centrifugal block and the auxiliary bevel gear, used to convert the radial displacement of the centrifugal block into the rotational motion of the auxiliary bevel gear. When the rotational speed of the chuck body exceeds a set threshold, the centrifugal block slides in a direction away from the axis of the chuck body, and the transmission assembly guides the auxiliary bevel gear to generate a rotational tendency to tighten the small bevel gear, thereby applying a locking effect to the large bevel gear through the small bevel gear.

[0004] While the above solution can guarantee clamping force, it makes the structure of the three-jaw chuck too complex and inconvenient for later maintenance. At the same time, in order to ensure clamping stability, the jaws on the three-jaw chuck need to apply a sufficiently large force to the shaft workpiece. This is because when machining the shaft workpiece, it will be subjected to circumferential torque. If the clamping force is insufficient, the shaft workpiece will rotate slightly on the three-jaw chuck. When the shaft workpiece rotates, the jaws will scratch the shaft workpiece. If the clamping force is too large, it will cause indentations on the shaft workpiece. Summary of the Invention

[0005] To address the aforementioned issues, a fixture for machining shaft workpieces is provided. By incorporating key components such as a follower block, a transmission unit including a limit block with a limiting groove, and a locking unit consisting of a pressing rod and a pressure sensor, this fixture achieves intelligent adaptive clamping of shaft workpieces of different materials: After the jaws initially clamp the shaft workpiece under hydraulic drive, the follower block moves synchronously with the jaws and drives the limit block to move through the limiting groove. At this time, the pressing rod follows but does not apply pressure. When the hydraulic line switches to the open passage state, the pressing rod actively advances and applies pressure to the pressure sensor. Through the mechanical transmission of the limiting groove, the jaws perform a secondary precision clamping of the shaft workpiece. The pressure sensor feeds back the clamping force data to the processor in real time. When the detected value reaches the preset rated clamping force matching the shaft workpiece material, the system immediately stops the pressing and switches the hydraulic line to the self-locking state, forming a mechanical-hydraulic dual redundant locking structure.

[0006] To address the problems of the prior art, the present invention provides a fixture for machining shaft workpieces, including a chuck and grippers for clamping the shaft workpiece; It also includes a follower block, a transmission unit, and a locking unit; The follower block is located on one side of the gripper and extends through the chuck along the axial direction of the chuck; The transmission unit is located on the side of the chuck away from the gripper and connected to the follower block. The transmission unit includes a limiting block that moves along the chuck axis. A limiting groove is formed on the limiting block. The extension direction of the limiting groove has an angle with the vertical direction. One side of the follower block extends into the limiting groove and moves in the limiting groove along the extension direction of the limiting groove. The locking unit is located on one side of the limiting block. The locking unit is used to lock the limiting block. The locking unit includes a pressing rod and a pressure sensor. The pressing rod is located on the side of the limiting block away from the chuck, which moves along the moving direction of the limiting block. The pressure sensor is located at the end of the limiting block facing the pressing rod and is used to detect the pressure value when the pressing rod presses the limiting block.

[0007] Preferably, a first roller is rotatably sleeved on the portion of the follower block that extends into the limiting groove, and the first roller rolls in cooperation with the side wall of the limiting groove.

[0008] Preferably, the locking unit further includes a pushing unit for moving the pressing rod, the pushing unit including a fixed plate, a lead screw, a push plate and a toothed ring; The fixing plate is located on the side of the chuck away from the jaws and remains stationary at all times; The lead screw passes through the fixed plate along the axis of the chuck and can move along the axis of the chuck. The push plate is fixedly installed along the axis of the lead screw at the end of the lead screw facing the chuck; The toothed ring is fitted around the outside of the lead screw and engages with the screw thread.

[0009] Preferably, the locking unit also includes a synchronization plate, which is fixedly connected to the ends of all the pressing rods, and the push plate presses the pressing rods through the synchronization plate.

[0010] Preferably, the synchronization plate has a ring structure, and multiple second rollers that rotate along the axis of the synchronization plate are provided on the synchronization plate. The second rollers are arranged around the axis of the synchronization plate.

[0011] Preferably, a washer is provided between the extrusion rod and the pressure sensor.

[0012] Preferably, the actuating unit further includes a guide rod and a guide sleeve; The guide rod is fixedly mounted on the push plate parallel to the axis of the chuck; The guide sleeve is fixedly mounted on the fixed plate along the extension direction of the guide rod, and the guide sleeve and the guide rod are in sliding fit.

[0013] Preferably, a clamping pad is provided on the clamping end face of the gripper, and the clamping pad is made of rubber.

[0014] Preferably, multiple grooves are provided on the end face of the clamping pad that contacts the shaft workpiece, and the grooves are arranged in an array.

[0015] Preferably, a snap-fit ​​groove is provided on the clamping end face of the gripper, and the clamping pad engages with the snap-fit ​​groove and is fixed by screws.

[0016] The advantages of this invention compared to the prior art are: 1. This invention, through the setting of key components such as a follower block, a transmission unit including a limit block with a limit groove, and a locking unit composed of a pressing rod and a pressure sensor, enables the intelligent adaptive clamping of shaft workpieces of different materials: After the jaws initially clamp the shaft workpiece under hydraulic drive, the follower block moves synchronously with the jaws and drives the limit block to move through the limit groove. At this time, the pressing rod follows but does not apply pressure. When the hydraulic line is switched to the open passage state, the pressing rod actively advances and applies pressure to the pressure sensor. Through the mechanical transmission of the limit groove, the jaws perform a secondary precision clamping of the shaft workpiece. The pressure sensor feeds back the clamping force data to the processor in real time. When the detected value reaches the preset rated clamping force that matches the material of the shaft workpiece, the system immediately stops the pressing and switches the hydraulic line to the self-locking state, forming a mechanical-hydraulic dual redundant locking structure. It ensures the clamping stability of hard shaft workpieces during machining, avoids surface damage to soft shaft workpieces caused by overpressure, and the dual locking mechanism significantly reduces the clamping loosening rate, thereby significantly improving the yield rate and equipment reliability of shaft parts machining.

[0017] 2. By setting a clamping pad on the clamping end face of the jaws, the jaws can indirectly clamp the shaft workpiece using the clamping pad, avoiding the damage to the surface of the shaft workpiece caused by the jaws directly clamping the shaft workpiece. When the jaws apply clamping force to the shaft workpiece, the clamping pad can deform after being subjected to force, increasing the contact area between the clamping pad and the shaft workpiece. At the same time, multiple grooves are opened on the clamping pad, which increases the friction coefficient of the clamping pad and also improves the clamping stability. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention, which is mounted on a base.

[0019] Figure 2 This is a three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention.

[0020] Figure 3 This is a three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention after part of the outer shell has been removed.

[0021] Figure 4 This is a side view of a fixture for machining shaft workpieces according to the present invention after part of the outer shell has been removed.

[0022] Figure 5 This invention relates to a fixture for machining shaft workpieces. Figure 4 Schematic diagram of cross-section at point AA.

[0023] Figure 6 This is a cross-sectional three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention.

[0024] Figure 7 This invention relates to a fixture for machining shaft workpieces. Figure 6 A magnified view of a portion of point B in the middle.

[0025] Figure 8 This invention relates to a fixture for machining shaft workpieces. Figure 6 A magnified view of a portion of point C.

[0026] Figure 9 This invention relates to a fixture for machining shaft workpieces. Figure 6 A magnified view of a portion of point D.

[0027] Figure 10 This is a three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention, after removing part of the pushing unit. Figure 1 .

[0028] Figure 11 This is a three-dimensional schematic diagram of a fixture for machining shaft workpieces according to the present invention, after removing part of the pushing unit. Figure 2 .

[0029] The diagram is labeled as follows: 1. Chuck; 11. Clamping jaw; 111. Follower block; 1111. First roller; 112. Clamping pad; 113. Groove; 12. Transmission unit; 121. Limiting block; 122. Limiting groove; 13. Locking unit; 131. Pressing rod; 132. Pressure sensor; 133. Pushing unit; 1331. Fixing plate; 1332. Lead screw; 1333. Push plate; 1334. Gear ring; 1335. Gear; 1336. Rotary actuator; 1337. Guide rod; 1338. Guide sleeve; 134. Synchronizing plate; 1341. Second roller; 135. Washer; 2. Shaft workpiece. Detailed Implementation

[0030] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Figures 1-11 A fixture for machining shaft workpieces includes a chuck 1 and grippers 11 for clamping the shaft workpiece 2; It also includes a follower block 111, a transmission unit 12, and a locking unit 13; The follower block 111 is disposed on one side of the gripper 11 and extends through the chuck 1 along the axial direction of the chuck 1; The transmission unit 12 is located on the side of the chuck 1 away from the gripper 11 and is connected to the follower block 111. The transmission unit 12 includes a limiting block 121 that moves along the axis of the chuck 1. A limiting groove 122 is formed on the limiting block 121. The extension direction of the limiting groove 122 has an angle with the vertical direction. One side of the follower block 111 extends into the limiting groove 122 and moves within the limiting groove 122 along the extension direction of the limiting groove 122. The locking unit 13 is disposed on one side of the limiting block 121. The locking unit 13 is used to lock the limiting block 121. The locking unit 13 includes a pressing rod 131 and a pressure sensor 132. The pressing rod 131 is disposed on the side of the limiting block 121 away from the chuck 1 along the moving direction of the limiting block 121. The pressure sensor 132 is disposed at the end of the limiting block 121 facing the pressing rod 131 and is used to detect the pressure value when the pressing rod 131 presses the limiting block 121.

[0032] In the existing technology, when machining the shaft workpiece 2, a chuck 1 with multiple jaws 11 is mainly used to clamp the shaft workpiece 2, so that the axis of the shaft workpiece 2 is collinear with the axis of the chuck 1. After clamping, the jaws 11 need to be locked. The existing locking methods are usually hydraulic locking or mechanical locking, but the locking force cannot be determined. Different shaft workpieces 2 have different materials, so when the clamping jaws 11 use the same force to clamp different shaft workpieces 2, the surface of the shaft workpiece 2 after processing will also have different results. If the material of the shaft workpiece 2 is relatively soft, the clamping force of the clamping jaws 11 should be reduced accordingly; otherwise, the clamping jaws 11 will leave indentations on the surface of the shaft workpiece 2. If the material of the shaft workpiece 2 is relatively hard, the clamping force of the clamping jaws 11 should be increased accordingly to improve the stability of the clamping jaws 11. Existing technologies prioritize the stability of the clamping, that is, when clamping the shaft workpiece 2, the clamping jaws 11 apply a large clamping force to the shaft workpiece 2 to ensure the stability of the clamping jaws 11. However, this will leave indentations on the surface of some shaft workpieces 2 with softer materials.

[0033] To avoid the aforementioned situation, the existing fixture was optimized so that it can apply different clamping forces to shaft workpieces 2 made of different materials, thereby reducing damage to the shaft workpieces 2 during clamping while ensuring clamping stability. The specific structure and working process of this invention are as follows: A processor is installed on one side of the pressure sensor 132 in the fixture. The pressure value detected by the pressure sensor 132 is fed back to the processor in real time. In use, the material of the shaft workpiece 2 is first input into the processor. The processor selects the corresponding rated clamping force according to the material of the shaft workpiece 2. Then, the shaft workpiece 2 is placed horizontally between all the jaws 11, so that the jaws 11 move under hydraulic action. All the jaws 11 set on the chuck 1 move synchronously towards the center of the chuck 1 and finally clamp the shaft workpiece 2. After clamping is completed, the hydraulic line used to drive the jaws 11 is in an open state. That is, when the jaws 11 are subjected to external force, the jaws 11 can move freely in the radial direction of the chuck 1. In addition, during the movement of the jaws 11, the follower block 111 moves synchronously with the jaws 11. The follower block 111 can react to the limit block 121 through the limit groove 122. When the gripper 11 is hydraulically driven, the limiting block 121 can be moved together by the follower block 111. This state, where the limiting block 121 is driven by the gripper 11, is referred to as the passive state. When the limiting block 121 is in the passive state, the pressing rod 131 moves together with the limiting block 121, and the pressure sensor 132 is not compressed and cannot detect the pressure value. After the gripper 11 completes clamping the shaft workpiece 2, the hydraulic line driving the gripper 11 switches to an open state. The pressing rod 131 moves towards the limiting block 121 and presses against the pressure sensor 132. Because the limiting groove 122 on the limiting block 121 is inclined, when the pressing rod 131 presses against the limiting block 121, the limiting block 121 uses the limiting groove 122 to push the follower block 111, causing the gripper 11 to further clamp the shaft workpiece 2. At this time, the pressure sensor 132 can detect the pressure value continuously rising. When the force reaches the rated clamping force, the extrusion rod 131 stops extruding and maintains the current state. Then, the hydraulic line used to drive the movement of the gripper 11 switches to the self-locking state, realizing the effect of mechanical and hydraulic double locking. By setting a redundant locking structure, the probability of clamping loosening when the gripper 11 clamps the shaft workpiece 2 is reduced. At the same time, the pressure sensor 132 detects the clamping force on the shaft workpiece 2 in real time, ensuring that when processing shaft workpieces 2 of different materials, there will be no loosening of the clamping force or indentation due to excessive clamping force.

[0034] By setting key components such as follower block 111, transmission unit 12 including limit block 121 with limit groove 122, and locking unit 13 composed of extrusion rod 131 and pressure sensor 132, the jig for processing shaft workpiece 2 achieves intelligent adaptive clamping of shaft workpiece 2 of different materials: when the jaw 11 initially clamps the shaft workpiece 2 under hydraulic drive, the follower block 111 moves synchronously with the jaw 11 and drives the limit block 121 to generate displacement through the limit groove 122. At this time, the extrusion rod 131 follows but does not apply pressure; when the hydraulic pipeline is switched to the open passage state, the extrusion rod 131 actively advances and applies pressure to the pressure sensor 132. Through the mechanical transmission of the limit groove 122, the jaw 11 performs secondary precision clamping on the shaft workpiece 2. The pressure sensor 132 feeds back the clamping force data to the processor in real time. When the detected value reaches the preset rated clamping force that matches the material of the shaft workpiece 2, the system immediately stops extrusion and switches the hydraulic pipeline to the self-locking state, forming a mechanical-hydraulic dual redundant locking structure. It ensures the clamping stability of the hard shaft workpiece 2 during processing, and avoids surface damage to the soft shaft workpiece 2 caused by overpressure. At the same time, the double locking mechanism greatly reduces the clamping loosening rate, significantly improving the yield rate and equipment reliability of shaft parts processing.

[0035] Reference Figure 7 A first roller 1111 is rotatably sleeved on the portion of the follower block 111 that extends into the limiting groove 122, and the first roller 1111 rolls with the side wall of the limiting groove 122.

[0036] By setting the first roller 1111, the follower block 111 contacts the limiting groove 122 through the first roller 1111, avoiding direct contact between the follower block 111 and the limiting groove 122. When the limiting block 121 applies pressure to the follower block 111 using the limiting groove 122, the wear between the follower block 111 and the limiting groove 122 can be reduced.

[0037] Reference Figures 2-7 The locking unit 13 also includes a pushing unit 133 for pushing the pressing rod 131 to move. The pushing unit 133 includes a fixed plate 1331, a lead screw 1332, a push plate 1333, and a toothed ring 1334. The fixing plate 1331 is located on the side of the chuck 1 away from the jaws and is always stationary; The lead screw 1332 passes through the fixed plate 1331 along the axis of the chuck 1 and can move along the axis of the chuck 1; The push plate 1333 is fixedly installed at the end of the lead screw 1332 facing the chuck 1 along the axis of the lead screw 1332; The toothed ring 1334 is sleeved around the lead screw 1332 and is threaded into the lead screw 1332.

[0038] The pushing unit 133 also includes a gear 1335 and a rotary driver 1336. The gear 1335 is rotatably mounted on one side of the gear ring 1334, and the rotary driver 1336 is mounted at the end of the gear 1335 and is used to drive the gear 1335 to rotate. The rotary driver 1336 is preferably a servo motor. The lead screw 1332 can only rotate along the axis of the chuck 1. The lead screw 1332 cannot rotate around its own axis. The specific structure for limiting the rotation of the lead screw 1332 will be described below. After the gear ring 1334 rotates under the drive of the rotary driver 1336 and the gear 1335, the lead screw 1332 drives the push plate 1333 to move towards the pressing rod 131.

[0039] Reference Figure 8 The locking unit 13 also includes a synchronization plate 134, which is fixedly connected to the ends of all the pressing rods 131. The push plate 1333 presses the pressing rods 131 through the synchronization plate 134.

[0040] After the gripper 11 clamps the shaft workpiece 2 under hydraulic pressure, the lead screw 1332 in the push unit 133 pushes the push plate 1333 towards the synchronous plate 134, causing the push plate 1333 to contact the synchronous plate 134. The thrust generated by the push plate 1333 is evenly distributed by the synchronous plate 134 to each pressing rod 131, causing each pressing rod 131 to move synchronously. When the processing is completed, the lead screw 1332 in the push unit 133 first drives the push plate 1333 to retract. After retraction, the push plate 1333 separates from the synchronous plate 134, and the locking unit 13 unlocks. Then, the hydraulic lines used to drive the movement of the gripper 11 are activated and drive the gripper 11 to separate.

[0041] Reference Figure 8 The synchronization plate 134 has a ring structure, and multiple second rollers 1341 are provided on the synchronization plate 134 to rotate along the axis of the synchronization plate 134. The second rollers 1341 are arranged around the axis of the synchronization plate 134.

[0042] During the locking process of the locking unit 13 locking the gripper 11, the push plate 1333 needs to continuously generate a pushing force on the synchronous plate 134, so that the clamping force of the gripper 11 on the shaft workpiece 2 continuously increases. After the clamping is completed, when the shaft workpiece 2 is processed, the chuck 1 needs to drive the shaft workpiece 2 to rotate, which causes the synchronous plate 134 to rotate under the drive of the pressing rod 131, which in turn causes friction between the end faces of the push plate 1333 and the synchronous plate 134. In order to reduce the friction, a second roller 1341 is provided on the synchronous plate 134, thereby reducing the wear of the synchronous plate 134 and the push plate 1333.

[0043] Reference Figure 8 A washer 135 is provided between the extrusion rod 131 and the pressure sensor 132.

[0044] By setting a washer 135, direct contact between the compression rod 131 and the pressure sensor 132 is avoided, and the washer 135 protects the pressure sensor 132.

[0045] Reference Figure 6 The push unit 133 also includes a guide rod 1337 and a guide sleeve 1338; The guide rod 1337 is fixedly mounted on the push plate 1333 parallel to the axis of the chuck 1; The guide sleeve 1338 is fixedly mounted on the fixed plate 1331 along the extension direction of the guide rod 1337, and the guide sleeve 1338 and the guide rod 1337 are in sliding fit.

[0046] The axis of the guide rod 1337 is not collinear with the axis of the chuck 1. Through the guidance of the guide rod 1337 and the guide sleeve 1338, it is ensured that when the gear ring 1334 rotates, the lead screw 1332 will not rotate on its own, and the lead screw 1332 can only move along the axis of the chuck 1.

[0047] Reference Figure 11 A clamping pad 112 is provided on the clamping end face of the gripper 11, and the clamping pad 112 is made of rubber.

[0048] By providing a clamping pad 112 on the clamping end face of the jaw 11, the jaw 11 indirectly clamps the shaft workpiece 2 using the clamping pad 112, avoiding damage to the surface of the shaft workpiece 2 when the jaw 11 directly clamps the shaft workpiece 2. Furthermore, when the jaw 11 applies a clamping force to the shaft workpiece 2, the clamping pad 112 deforms under the force, increasing the contact area between the clamping pad 112 and the shaft workpiece 2, thus improving the stability of the clamping.

[0049] Reference Figure 11 Multiple grooves 113 are provided on the end face of the clamping pad 112 that contacts the shaft workpiece 2, and the grooves 113 are arranged in an array.

[0050] By setting multiple grooves 113 on the clamping pad 112, the coefficient of friction between the shaft workpiece 2 and the clamping pad 112 is increased, further improving the stability of clamping the shaft workpiece 2.

[0051] Reference Figure 9 A snap-fit ​​groove is provided on the clamping end face of the gripper 11, and the clamping pad 112 is engaged with the snap-fit ​​groove and fixed by screws.

[0052] By creating a snap-fit ​​groove on the clamping end face of the gripper 11 and tightening the clamping pad 112 into the snap-fit ​​groove with screws, it is convenient to replace the clamping pad 112 in the future.

[0053] Working principle: In use, the material of the shaft workpiece 2 is first input into the processor. The processor selects the corresponding rated clamping force according to the material of the shaft workpiece 2. Then, the shaft workpiece 2 is placed horizontally between all the jaws 11, so that the jaws 11 move under hydraulic action. All the jaws 11 set on the chuck 1 move synchronously towards the center of the chuck 1 and finally clamp the shaft workpiece 2. After clamping is completed, the hydraulic line used to drive the jaws 11 is in an open state, that is, when the jaws 11 are subjected to external force, the jaws 11 can move freely in the radial direction of the chuck 1. In addition, during the movement of the jaws 11, the follower block 111 moves synchronously with the jaws 11. The follower block 111 can react on the limit block 121 through the limit groove 122. When the gripper 11 is hydraulically driven, the limit block 121 can be moved together by the follower block 111. Here, the state in which the limit block 121 is moved by the gripper 11 is called the passive state. When the limit block 121 is in the passive state, the extrusion rod 131 moves together with the limit block 121, and the pressure sensor 132 is not extruded, so the pressure sensor 132 cannot detect the pressure value. After the gripper 11 completes clamping the shaft workpiece 2, the hydraulic line used to drive the gripper 11 switches to the open passage state. The pressing rod 131 moves toward the limiting block 121 and presses the pressure sensor 132. Since the limiting groove 122 on the limiting block 121 is in an inclined state, when the pressing rod 131 presses the limiting block 121, the limiting block 121 uses the limiting groove 122 to push the follower block 111, so that the gripper 11 further clamps the shaft workpiece 2. At this time, the pressure sensor 132 can detect that the pressure value is rising continuously. When the pressure value reaches the rated clamping force, the pressing rod 131 stops pressing and maintains the current state. Then, the hydraulic line used to drive the movement of the gripper 11 switches to the self-locking state, realizing the effect of mechanical and hydraulic double locking. By setting a redundant locking structure, the probability of clamping loosening when the gripper 11 clamps the shaft workpiece 2 is reduced.

[0054] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A fixture for machining a shaft workpiece, comprising a chuck (1) and grippers (11) for clamping the shaft workpiece (2); Its features are, It also includes a follower block (111), a transmission unit (12), and a locking unit (13). The follower block (111) is located on one side of the gripper (11) and passes through the chuck (1) along the axial direction of the chuck (1). The transmission unit (12) is located on the side of the chuck (1) away from the gripper (11) and connected to the follower block (111). The transmission unit (12) includes a limiting block (121) that moves along the axis of the chuck (1). A limiting groove (122) is provided on the limiting block (121). The extension direction of the limiting groove (122) has an angle with the vertical direction. One side of the follower block (111) extends into the limiting groove (122) and moves in the limiting groove (122) along the extension direction of the limiting groove (122). The locking unit (13) is set on one side of the limiting block (121). The locking unit (13) is used to lock the limiting block (121). The locking unit (13) includes a pressing rod (131) and a pressure sensor (132). The pressing rod (131) is moved along the moving direction of the limiting block (121) and is set on the side of the limiting block (121) away from the chuck (1). The pressure sensor (132) is set at one end of the limiting block (121) facing the pressing rod (131) and is used to detect the pressure value when the pressing rod (131) presses the limiting block (121). The pressure sensor (132) feeds back the clamping force data to the processor in real time. When the detected value reaches the preset rated clamping force that matches the material of the shaft workpiece (2), the system immediately stops pressing and switches the hydraulic pipeline to the self-locking state, forming a mechanical-hydraulic dual redundant locking structure. A clamping pad (112) is provided on the clamping end face of the gripper (11), and the clamping pad (112) is made of rubber. Multiple grooves (113) are provided on the end face of the clamping pad (112) that contacts the shaft workpiece (2), and the grooves (113) are arranged in an array. A snap-fit ​​groove is provided on the clamping end face of the gripper (11), and the clamping pad (112) is engaged with the snap-fit ​​groove and fixed by screws.

2. The fixture for machining shaft workpieces according to claim 1, characterized in that, A first roller (1111) is rotatably sleeved on the portion of the follower block (111) that extends into the limiting groove (122), and the first roller (1111) rolls in cooperation with the side wall of the limiting groove (122).

3. The fixture for machining shaft workpieces according to claim 1, characterized in that, The locking unit (13) also includes a pushing unit (133) for pushing the pressing rod (131) to move. The pushing unit (133) includes a fixed plate (1331), a lead screw (1332), a push plate (1333) and a toothed ring (1334). The fixing plate (1331) is located on the side of the chuck (1) away from the jaws (11) and is always stationary; The lead screw (1332) passes through the fixed plate (1331) along the axis of the chuck (1) and can move along the axis of the chuck (1); The push plate (1333) is fixedly installed at the end of the lead screw (1332) facing the chuck (1) along the axis of the lead screw (1332); The toothed ring (1334) is sleeved on the periphery of the lead screw (1332) and is threaded into the lead screw (1332).

4. A fixture for machining shaft workpieces according to claim 3, characterized in that, The locking unit (13) also includes a synchronization plate (134), which is fixedly connected to the ends of all the pressing rods (131). The push plate (1333) presses the pressing rods (131) through the synchronization plate (134).

5. A fixture for machining shaft workpieces according to claim 4, characterized in that, The synchronization plate (134) is a ring structure. Multiple second rollers (1341) are provided on the synchronization plate (134) and rotate along the axis of the synchronization plate (134). The second rollers (1341) are arranged around the axis of the synchronization plate (134).

6. A fixture for machining shaft workpieces according to claim 1, characterized in that, A washer (135) is provided between the extrusion rod (131) and the pressure sensor (132).

7. A fixture for machining shaft workpieces according to claim 3, characterized in that, The push unit (133) also includes a guide rod (1337) and a guide sleeve (1338). The guide rod (1337) is fixedly mounted on the push plate (1333) parallel to the axis of the chuck (1); The guide sleeve (1338) is fixedly mounted on the fixed plate (1331) along the extension direction of the guide rod (1337), and the guide sleeve (1338) and the guide rod (1337) are in sliding fit.

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