Chuck body hardening method

Abstract

To provide a chuck body hardening method which can easily uniformize the hardening of the sliding faces of guide grooves plurally formed at the chuck body.SOLUTION: A nozzle 13 is arranged for applying a laser to the upper part or the side part of a chuck body 5, laser hardening is executed to a sliding face 11A of an upper part 9 of a guide groove 7 of the chuck body 5, and laser hardening is subsequently executed to a sliding face 11C of a base part 8. Thereafter, laser hardening is executed to a sliding face 11E of the upper part 9 of the guide groove 7 and a sliding face 11G of the base part 8. Successively, laser hardening is executed to sliding faces 11B, 11D of the base part 8, and laser hardening is then executed to sliding faces 11F, 11H of the base part 8.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a chuck in which claws are fixed to a master jaw that reciprocates in the radial direction of the chuck by a driving member that moves in the axial direction of the chuck, and the claws are used to clamp and unclamp a workpiece. Chuck body the driving member is accommodated in a through hole formed in the chuck body, the master jaws are accommodated in a plurality of guide grooves formed in the chuck body, and the sliding surfaces provided in the through holes and the guide grooves are hardened to prevent wear of the sliding surfaces due to reciprocating motion of the driving member and the master jaws. [Background technology]

[0002] As described in Patent Document 1, it is known that the surface of the guide groove 40 of the chuck main body 20 (chuck body) is hardened by quenching. In conventional chuck bodies, the quenching is mainly performed by induction hardening. In induction hardening, a coil is placed near the through hole or guide groove that has a sliding surface on which the part slides, and the sliding surface of the through hole or guide groove is rapidly heated by using a high-frequency induction current flowing through the coil, and then immediately cooled rapidly with a coolant such as water, thereby hardening the surface of the sliding surface of the through hole or guide groove. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5735086 Summary of the Invention [Problem to be solved by the invention]

[0004] The guide groove of the above-mentioned chuck body has a T-shaped cross section having a wide base and an upper part narrower than the base, and a plurality of sliding surfaces are provided at the base and the upper part. In order to harden the surfaces of the plurality of sliding surfaces of the guide groove at once by conventional induction hardening, a coil of a shape corresponding to the guide groove must be provided. If the coil is not always positioned at a constant distance from the guide groove, heat cannot be applied uniformly to each sliding surface, and each sliding surface cannot be hardened to a uniform hardness. Therefore, there is a risk that the sliding surfaces with low hardness will wear due to the reciprocating motion of the master jaw, affecting the reciprocating motion of the master jaw. In view of the above problems, an object of the present invention is to provide a method for hardening a chuck body that can easily make the hardening of the sliding surface of the chuck body uniform. [Means for solving the problem]

[0005] The present invention relates to a chuck in which claws are fixed to a master jaw that reciprocates in the radial direction of the chuck by a driving member that moves in the axial direction of the chuck, and the claws are used to clamp and unclamp a workpiece. Chuck body In a hardening method for a chuck body, the driving member is accommodated in a through hole formed in the chuck body, the master jaws are accommodated in a plurality of guide grooves formed in the chuck body, and the sliding surfaces provided in the through holes and the guide grooves are hardened to prevent wear of the sliding surfaces provided in the through holes and the guide grooves due to reciprocating motion of the driving member and the master jaws, the sliding surfaces are hardened by laser hardening. Specifically, the guide groove has a T-shaped cross section having a wide base and an upper portion narrower than the base, and a plurality of sliding surfaces are provided at the base and the upper portion, and after laser hardening is performed on the sliding surface of a first guide groove, the chuck body is rotated, and laser hardening is performed on the sliding surfaces of the remaining guide grooves located at the same positions as the sliding surfaces. Effect of the Invention

[0006] In the present invention, by performing laser hardening on the sliding surfaces of the guide grooves formed in the chuck body, the trouble of arranging the coil at a constant distance from the guide groove is eliminated, and the sliding surfaces of the guide grooves can be hardened to a uniform hardness. Furthermore, since there are no sliding surfaces with low hardness, it is possible to prevent the influence on the reciprocating motion of the master jaws. In addition, when hardening the sliding surfaces of the guide grooves formed in the circumferential direction, the sliding surfaces at the same position of each guide groove are hardened, and laser hardening is not performed on consecutive sliding surfaces, so that it is possible to prevent overlapping of hardened areas that leads to tempering. [Brief description of the drawings]

[0007] [Figure 1] FIG. 13 is a diagram showing the chuck with some of the jaws disengaged; [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] 3 is a view taken from the direction III in FIG. 2, showing a guide groove. FIG. [Figure 4] FIG. [Diagram 5] 13A and 13B are diagrams showing other shapes of the guide groove. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The chuck 1 shown in Fig. 1 is configured to clamp and unclamp a workpiece with jaws 4 attached to a master jaw 3 that is reciprocated in the radial direction of the chuck by the reciprocating motion of a driving member 2. The driving member 2 is housed in a through hole 6 formed in a chuck body 5, and the master jaws 3 are housed in a plurality of guide grooves 7 formed in the circumferential direction of the chuck body 5. As shown in Fig. 3, the guide groove 7 has a T-shaped cross section having a wide base portion 8 and an upper portion 9 that is narrower than the base portion 8. The upper portion 9 opens toward the front of the chuck body 5. A groove portion 10 is provided in the center of the base portion 8.

[0009] The guide groove 7 is provided with a plurality of sliding surfaces 11A-11H for guiding the master jaw 3, and the sliding surfaces 11A-11H are hardened by quenching to prevent them from being worn down due to the reciprocating motion of the master jaw 3. The through hole 6 is provided with a sliding surface 6A for guiding the wedge plunger 12 of the driving member 2, and the sliding surface 6A is hardened by quenching to prevent them from being worn down due to the reciprocating motion of the wedge plunger 12.

[0010] The sliding surfaces 11A to 11H of the guide groove 7 and the sliding surface 6A of the through hole 6 are hardened by laser hardening. In the laser hardening, the sliding surfaces 11A to 11H of the guide groove 7 and the sliding surface 6A of the through hole 6 are rapidly heated by irradiating a laser, and the surface temperatures of the sliding surfaces 11A to 11H of the guide groove 7 and the sliding surface 6A of the through hole 6 are suddenly increased. After that, when the laser hardening portion is moved, the surface temperature of the laser hardening portion is rapidly decreased by self-cooling, and the surfaces of the sliding surfaces 11A to 11H of the guide groove 7 and the sliding surface 6A of the through hole 6 can be hardened. Furthermore, the hardness of the hardened portion can be made uniform by uniformly moving the laser.

[0011] Next, a method of hardening the sliding surfaces 11A to 11H of the guide groove 7 will be described. A nozzle 13 for irradiating a laser is disposed above or to the side of the chuck body 5. The chuck body 5 is installed so as to rotate about the chuck axis CL. The nozzle 13 is provided so as to be able to irradiate a laser in the radial direction of the chuck. In this embodiment, the nozzle 13 rotates or moves to perform laser hardening on the sliding surface 11A of the upper portion 9 of the guide groove 7 of the chuck body 5, and then performs laser hardening on the sliding surface 11C of the base 8. Then, the sliding surface 11E of the upper portion 9 of the guide groove 7 and the sliding surface 11G of the base 8 are laser hardened. Next, the sliding surfaces 11B and 11D of the base 8 are laser hardened, and then the sliding surfaces 11F and 11H of the base 8 are laser hardened. In this way, by not performing laser hardening on the continuous sliding surfaces 11A to 11H, it is possible to prevent overlapping of hardened portions that leads to tempering. Thereafter, the chuck body 5 was rotated, and the remaining sliding surfaces 11A to 11H provided in the second and third guide grooves 7B and 7C were hardened by the above-mentioned operation.

[0012] From the above, by performing laser hardening on the sliding surfaces 11A-11H provided on each guide groove 7A-7C, the trouble of arranging the coil at a constant distance from the sliding surfaces 11A-11H of the guide groove 7 as in the conventional method is eliminated, and the sliding surfaces 11A-11H of each guide groove 7A-7C can be hardened to have a uniform hardness. Furthermore, since there is no sliding surface with a low hardness, it is possible to prevent an influence on the reciprocating movement of the master jaw 3. Furthermore, although some guide grooves 7 have a narrow gap in the vertical direction of the base 8 as shown in FIG. 5, by forming a groove portion 10A through which a laser can pass, it is possible to harden each of the sliding surfaces 11A-11H to have a uniform hardness, similar to the above-mentioned guide groove 7.

[0013] In another embodiment, as shown in Fig. 4, after laser hardening is performed on the sliding surface 11A of the upper portion 9 of the first guide groove 7A, the chuck body 5 is rotated, and the sliding surface 11A at the same position as the sliding surface 11A of the second guide groove 7B is laser hardened. Furthermore, the chuck body 5 is rotated, and the sliding surface 11A at the same position as the sliding surface 11A of the third guide groove 7C is laser hardened. After that, the nozzle 13 is moved, and the sliding surface 11E of the upper portion 9 of the first guide groove 7A, the sliding surface 11E of the upper portion 9 of the second guide groove 7B, and the sliding surface 11E of the upper portion 9 of the third guide groove 7C are laser hardened. In this way, when hardening the sliding surfaces 11A-11H of the guide grooves 7A-7C that are formed in multiple locations in the circumferential direction, hardening is performed only on the sliding surfaces 11A-11H that are located at the same position in each guide groove 7A-7C, and laser hardening is not performed on consecutive sliding surfaces 11A-11H, thereby preventing overlapping of hardened areas that could lead to tempering. [Explanation of symbols]

[0014] 1 Chuck 2 Driving member 3 Master Joe 4 Claws 5 Chuck Body 6 Through holes 6A Sliding surface 7 Guide groove 8 base 9. Top 11A~11H Sliding surface

Claims

1. A chuck body of a chuck configured to clamp and unclamp a workpiece by a master jaw having claws fixed thereto, the master jaw being reciprocated in a radial direction of the chuck by a driving member moving in a chuck axial direction, the master jaw having claws fixed thereto, the driving member being accommodated in a through hole formed in the chuck body, the master jaw being accommodated in a plurality of guide grooves formed in the chuck body, and a method for hardening a sliding surface provided in the through hole or guide groove to prevent the sliding surface from being worn down by the reciprocating movement of the driving member and the master jaw, the method for hardening a chuck body characterized in that the sliding surface provided in the through hole or guide groove is hardened by laser hardening.

2. 2. The method for hardening a chuck body according to claim 1, wherein a plurality of said guide grooves are formed in the circumferential direction of the chuck body, each guide groove having a T-shaped cross section having a wide base portion and an upper portion narrower than the base portion, a plurality of sliding surfaces are provided on the base portion and the upper portion, and after laser hardening is performed on any one of the sliding surfaces of the first guide groove, by rotating the chuck body, laser hardening is sequentially performed on the sliding surfaces of the second guide groove and the third guide groove which are located in the same position as the sliding surface.

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