Clamping tool for machining coaxiality of blind holes at both ends of workpiece

Abstract

This utility model discloses a clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece. It includes a clamping cylinder with openings on its side walls, threaded holes at the center of both ends of the cylinder, and hollow clamping members threaded into these holes. The hollow clamping members have a channel in their center for a grinding head to pass through, and a tapered surface at their front end. The hollow clamping members at both ends of the clamping cylinder engage with the tapered reference openings at both ends of the workpiece through their tapered surfaces, thus centering and securing the workpiece within the clamping cylinder. In use, the workpiece is first fixed inside the clamping cylinder, and then the clamping cylinder is fixed to a machine tool. As a tooling fixture, the clamping cylinder has high precision. When clamping both ends using the machine tool's four-jaw chuck, the positive and side generatrices of the outer circle of the clamping cylinder can be aligned to ensure that the axis of the clamping cylinder coincides during the two clamping processes, thereby ensuring the coaxiality of the blind holes at both ends of the workpiece.

Description

Technical Field

[0001] This utility model relates to the field of tooling fixtures, and in particular to a clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece. Background Technology

[0002] In the machinery manufacturing industry, there are shaft-type parts with blind holes at both ends, such as gear shafts, and the coaxiality of the blind holes at both ends of the part is required to be high. When machining the blind holes of such parts, one end of the workpiece is usually clamped directly on the three-jaw chuck of the machine tool, and then the blind hole at the other end is machined. After machining, the workpiece position is changed to machine the other blind hole. The disadvantage of this machining method is that, since there is no unified alignment datum for the two clamping operations, it is difficult to ensure that the axes of the two clamping operations coincide, resulting in the coaxiality of the blind holes at both ends being difficult to guarantee. Utility Model Content

[0003] To overcome the shortcomings of existing direct clamping machining, such as low coaxiality of blind holes at both ends of the workpiece, the technical problem to be solved by this utility model is to provide a clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece that can ensure coaxiality.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece includes a clamping cylinder. The side wall of the middle part of the clamping cylinder is provided with an opening for inserting the workpiece. Threaded holes are provided at the center positions of both ends of the clamping cylinder. Hollow clamping members are threadedly connected to the threaded holes. The middle part of the hollow clamping member is provided with a channel for a grinding head to pass through. The front end of the hollow clamping member is provided with a tapered surface. The hollow clamping members at both ends of the clamping cylinder cooperate with the tapered reference openings at both ends of the workpiece through the tapered surfaces to center and firmly fix the workpiece inside the clamping cylinder.

[0006] Furthermore, the opening includes two openings, which are symmetrically arranged on both sides of the clamping cylinder.

[0007] Furthermore, both ends of the clamping cylinder are provided with threaded holes and through holes from the outside to the inside. The hollow clamping member includes a hollow center and a hollow nut. The hollow center is slidably disposed in the through hole, and the hollow nut is threadedly connected to the threaded hole. A spring is provided between the hollow nut and the hollow center.

[0008] Furthermore, the spring is a rubber pad or a disc spring.

[0009] Furthermore, it also includes a support frame, the top of which is provided with a clamping element that can provide auxiliary support for the clamping cylinder.

[0010] Furthermore, the clamping component includes a support ring and three screw holes evenly spaced on the support ring. The axis of the screw holes is consistent with the radial direction of the support ring. A clamping screw is threaded into the screw hole, and a support block is provided at the end of the clamping screw that contacts the clamping cylinder.

[0011] Furthermore, the support block is rotatably connected to the clamping screw, and the side of the support block that contacts the clamping cylinder has an arc-shaped surface that matches the outer circle of the clamping cylinder.

[0012] The beneficial effects of this utility model are: first, the workpiece is fixed in a clamping cylinder, and then the clamping cylinder is fixed on the machine tool as a tooling fixture. The clamping cylinder has high precision. When the machine tool's four-jaw chuck clamps both ends of the workpiece, the positive generatrix and side generatrix of the outer circle of the clamping cylinder can be aligned to ensure that the axis of the clamping cylinder coincides during the two clamping processes, thereby ensuring the coaxiality of the blind hole machining at both ends of the workpiece. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the workpiece processed by this utility model;

[0014] Figure 2 This is a main sectional view of the present invention;

[0015] Figure 3 This is a side sectional view of the present invention;

[0016] Figure 4 yes Figure 2 An enlarged view of section A.

[0017] The markings in the diagram are as follows: 1- Clamping cylinder, 2- Workpiece, 3- Hollow clamping component, 4- Grinding head, 5- Support frame, 6- Four-jaw chuck, 11- Opening, 12- Threaded hole, 13- Through hole, 21- Blind hole, 31- Hollow center, 32- Hollow nut, 33- Spring piece, 34- Channel, 51- Support ring, 52- Threaded hole, 53- Clamping screw, 54- Support block, 55- Arc-shaped surface. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] It should be noted that if this utility model contains directional indicators such as up, down, left, right, front, and back, these terms are used to describe the relative positional relationships between components and are not specific references to the absolute positions of the components or the relationships between them. They are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indicator will also change accordingly. If this utility model contains terms related to quantity such as "many," "multiple," or "several," these terms specifically refer to two or more.

[0020] Figure 1 The workpiece 2 targeted by this utility model has a blind hole 21 at each end, and the coaxiality of the blind holes 21 at both ends of the workpiece 2 is required to be 0.01 mm. The clamping fixture provided by this utility model for machining the coaxiality of the blind holes at both ends of the workpiece is as follows: Figure 2 As shown, the fixture includes a clamping cylinder 1. An opening 11 for inserting a workpiece 2 is provided on the side wall of the middle section of the clamping cylinder 1. Threaded holes 12 are provided at the center positions of both ends of the clamping cylinder 1. Hollow clamping members 3 are internally threaded into the threaded holes 12. A channel 34 for a grinding head 4 to pass through is provided in the middle of the hollow clamping member 3. A tapered surface is provided at the front end of the hollow clamping member 3. The hollow clamping members 3 at both ends of the clamping cylinder 1 engage with the tapered reference openings at both ends of the workpiece 2 through their tapered surfaces, thus centering and firmly fixing the workpiece 2 inside the clamping cylinder 1. As a tooling fixture, the clamping cylinder 1 should have high precision, including the straightness, coaxiality, and radial runout of its outer circle, as well as the coaxiality of the threaded holes at both ends, to ensure that the hollow clamping members 3 at both ends also have high coaxiality, which cannot be lower than the coaxiality requirement of the blind hole 21.

[0021] The clamping and processing process of this utility model is as follows: This process mainly involves precision machining of the blind hole 21. Therefore, in the previous process, the blind hole 21 needs to be rough machined at both ends of the workpiece 2, and the opening of the blind hole 21 needs to be chamfered to create a reference opening. The chamfer of the reference opening is the same as the angle of the tapered surface at the front end of the hollow clamping member 3, for example, both are 60°. Then, the workpiece 2 is placed into the workpiece 2 through the opening 11 on the side of the clamping cylinder 1, and then the hollow clamping members 3 at both ends are rotated to bring them closer to the center and press against the reference openings at both ends of the workpiece 2. The workpiece is clamped and fixed. Then, one end of the clamping cylinder 1 is mounted on the four-jaw chuck 6 of the machine tool. During clamping, the positive and side generatrices on the outer circumference of the clamping cylinder 1 are aligned by adjusting the soft jaws. After clamping, the grinding head 4 is inserted into the channel 34 of the hollow clamping member 3 at the other end of the clamping cylinder 1. The four-jaw chuck 6 drives the clamping cylinder 1 to rotate, and the rotation and movement of the grinding head 4 are used to perform grinding and finishing of the blind hole 21. After machining, the clamping cylinder 1 is removed, and the other end is clamped using the same method. Then, another blind hole 21 is machined. This invention uses a clamping cylinder 1 to fix the workpiece, and uses the clamping cylinder 1 as an alignment reference during two clamping processes to ensure the coincidence of the axes of the blind holes 21 at both ends of the workpiece 2 during the two clamping processes, thereby improving clamping efficiency and reducing the scrap rate.

[0022] like Figure 3 As shown, in order to facilitate fixing the workpiece 2 into the clamping cylinder 1, two openings 11 can be symmetrically provided on both sides of the clamping cylinder 1, so that the workpiece 2 can be held by hand from both sides during the fixing process.

[0023] A threaded connection alone may not guarantee the clamping effect of the hollow clamping member 3 on the workpiece 2. Therefore, to prevent the hollow clamping member 3 from loosening during processing, the preferred solution is, as follows: Figure 4 As shown, threaded holes 12 and through holes 13 are sequentially provided at both ends of the clamping cylinder 1 from the outside to the inside. The hollow clamping member 3 includes a hollow center 31 and a hollow nut 32. The hollow center 31 is slidably disposed in the through hole 13, and the hollow nut 32 is threadedly connected to the threaded hole 12. A spring piece 33 is provided between the hollow nut 32 and the hollow center 31. During clamping, the hollow nut 32 pushes the spring piece 33, which in turn pushes the hollow center 31 to move towards the middle of the clamping cylinder 1. When the hollow center 31 abuts against the workpiece 2, the hollow nut 32 is rotated to compress the spring piece 33. The reaction force of the spring piece 33 applies a preload to the hollow nut 32, making it tightly connected to the threaded hole 12, thereby preventing the hollow clamping member 3 from loosening. The spring piece 33 can be a rubber pad or a disc spring, with a disc spring being preferred as it provides greater elasticity.

[0024] Furthermore, for some longer workpieces, to prevent radial runout of the clamping cylinder 1 during processing, an additional support frame 5 can be added. The top of the support frame 5 is equipped with a clamping element that provides auxiliary support for the clamping cylinder 1. The specific structure of the clamping element can be as follows: Figure 2 , Figure 3 As shown, the system includes a support ring 51 and three evenly spaced screw holes 52 on the support ring 51. The axis of the screw holes 52 is aligned with the radial direction of the support ring 51. A clamping screw 53 is internally threaded into each screw hole 52. A support block 54 is provided at the end of the clamping screw 53 that contacts the clamping cylinder 1. When clamping and fixing the clamping cylinder 1, the positive and side generatrices on the outer circumference of the cylinder are aligned by simultaneously adjusting the soft jaws of the four-jaw chuck 6 and the three clamping screws 53. The four-jaw chuck 6 clamps and fixes one end of the clamping cylinder 1, while the support frame 5 provides auxiliary support to the other end of the clamping cylinder 1 through the clamping screws 53 and the support block 54. This auxiliary support means that it only supports, does not fix, and does not affect the rotation of the clamping cylinder 1 with the four-jaw chuck 6, thereby preventing radial runout of the clamping cylinder 1, ensuring the stability of the workpiece 2 during grinding, and ensuring machining accuracy.

[0025] Preferably, the support block 54 is rotatably connected to the clamping screw 53, and the side of the support block 54 that contacts the clamping cylinder 1 has an arc-shaped surface 55 that matches the outer circle of the clamping cylinder 1. The arc-shaped surface 55 can increase the contact area between the support block 54 and the clamping cylinder 1, thereby providing better auxiliary support and positioning for the clamping cylinder 1. The rotatable connection between the support block 54 and the clamping screw 53 can prevent the support block 54 from rotating when the clamping screw 53 is rotated.

Claims

1. A clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece, characterized in that: The clamping cylinder (1) includes an opening (11) on the side wall of the middle part of the clamping cylinder (1) for inserting the workpiece (2). Threaded holes (12) are provided at the center of both ends of the clamping cylinder (1). Hollow clamping parts (3) are threadedly connected in the threaded holes (12). The middle part of the hollow clamping parts (3) is provided with a channel (34) for the grinding head (4) to pass through. The front end of the hollow clamping parts (3) is provided with a tapered surface. The hollow clamping parts (3) at both ends of the clamping cylinder (1) cooperate with the tapered reference openings at both ends of the workpiece (2) through the tapered surface to center and fix the workpiece (2) in the clamping cylinder (1).

2. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in claim 1, characterized in that: The opening (11) includes two, and is symmetrically arranged on both sides of the clamping cylinder (1).

3. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in claim 1, characterized in that: The clamping cylinder (1) has threaded holes (12) and through holes (13) at both ends from the outside to the inside. The hollow clamping member (3) includes a hollow tip (31) and a hollow nut (32). The hollow tip (31) is slidably disposed in the through hole (13). The hollow nut (32) is threadedly connected to the threaded hole (12). A spring piece (33) is provided between the hollow nut (32) and the hollow tip (31).

4. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in claim 3, characterized in that: The spring (33) is a rubber pad or a disc spring.

5. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in any one of claims 1-4, characterized in that: It also includes a support frame (5), the top of which is provided with a clamping member that can provide auxiliary support for the clamping cylinder (1).

6. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in claim 5, characterized in that: The clamping component includes a support ring (51) and three screw holes (52) evenly spaced on the support ring (51). The axis of the screw holes (52) is consistent with the radial direction of the support ring (51). The screw holes (52) are internally threaded with a clamping screw (53). The end of the clamping screw (53) that contacts the clamping cylinder (1) is provided with a support block (54).

7. The clamping fixture for machining the coaxiality of blind holes at both ends of a workpiece as described in claim 6, characterized in that: The support block (54) is rotatably connected to the clamping screw (53), and the side of the support block (54) that contacts the clamping cylinder (1) is provided with an arc-shaped surface (55) that matches the outer circle of the clamping cylinder (1).

Images