JPH071211Y2 - Lathe chuck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a chuck for connecting a spindle of a lathe and an end of a workpiece.

[Conventional technology]

Conventionally, chucks generally used in lathes are
A support portion that abuts an end portion of the work piece, and a plurality of claw members that come into contact with and separate from the work piece that is in a state of abutting the support portion are provided. It has a structure that holds the parts. Further, the contact / separation of each claw member with respect to the workpiece is individually adjusted by the rotation of the screw or the like.

[Problems to be solved by the device]

In the structure in which each claw member is individually moved as described above, it is necessary to adjust the tightening force by the feel of the operator, so it is difficult to press each claw member against the workpiece with a uniform force, Generally, the force with which each claw member is pressed against the workpiece varies. In this way, when the tightening force is different depending on each claw member, the shearing force in the direction perpendicular to the axial center acts on the support portion that supports the workpiece,
The strength is not preferable. In particular, the chuck used in the lathe must transmit a very large torque to the work piece, which requires a large tightening force on the work piece. The shear force generated when the stress is not uniform is not negligible, and its improvement has been a problem.

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a chuck for a lathe capable of pressing each claw member against a work piece with a substantially uniform pressure to clamp the work piece with a simple operation. .

[Means for Solving the Problems]

The present invention is configured such that a support portion that abuts on the center of an end of a work piece and a direction in which the work piece that is in contact with the support portion moves toward and away from each other, and that the work piece is sandwiched. In a chuck of a lathe provided with at least a pair of facing claw members, there are mutually opposite screws penetrating the supporting portion and screwed into the pair of claw members, respectively, and by rotating the pair, the pair of And a screw member for simultaneously moving the claw member along the axial direction of rotation, and the screw member is provided in a portion penetrating the support portion, and the screw member is the same as the moving direction of the claw member with respect to the support portion. And a urging means for urging the screw member in a direction in which the screw member is returned to a reference position where the distance between the pair of claw members and the supporting portion is equal to each other. It is a thing.

[Action]

In such a configuration, when the screw member is rotated, the pair of claw members simultaneously move toward and away from the workpiece. Moreover, since the screw member can move in the same direction as the moving direction of the pawl member while being urged in the direction of returning to the reference position, even if the workpiece contacting the support portion is eccentric,
By moving the screw member and the claw member integrally according to the amount of eccentricity, each claw member is always pressed against the workpiece with a substantially uniform force.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In these figures, reference numeral 1 is a main body of a chuck connected to a main shaft of a lathe. A support member 2 for supporting a work (workpiece) W is fixed to the center of the chuck body 1, and a recess formed at the end face of the support member 2 at the center of the end of the work W. A supporting portion (center member) 3 having a conical shape is provided so as to abut.

Claw members (only the claw members 41 to 43 are shown in the figure) which are slidable in the direction toward and away from the support part 3 are attached to the chuck 1 main body at four positions surrounding the support part 3. Has been. These claw members are arranged such that a claw member 41 and a claw member 42, and a claw member 43 and a claw member (not shown) are paired so as to face each other, and are in a state of abutting on the support portion 3. The structure is such that W can be held from both sides.

On the other hand, in the chuck body 1, two screw shafts (screw members) 51, 52 are arranged so as to intersect each other in different steps, and these are in a state of penetrating the support member 2 and a predetermined claw member. It is rotatably supported by the main body 1.

The screw shaft 51 has mutually opposite threaded portions 51a, 51b between its both ends and the central portion, and these screwed portions 51a, 51b are respectively formed in the screw holes provided in the claw members 41, 42. It is screwed. On the other hand, the central portion penetrates through the support member 2 while being supported by the support member 2 via the sliding bearing 10, and the screw shaft 51 with respect to the support member 2 has the claw member 41. , 42 are movable in the axial direction (that is, the direction in which the claw members 41, 42 can slide).

On the other hand, both ends of the screw shaft 51 are rotatably supported on the inner wall of a cylindrical portion 1a integrally provided in the chuck body 1 via bearings 6, and the tip end portion thereof is externally moved from the cylindrical portion 1a. An operating portion 7 having a hexagonal cross section is formed on each of these portions. Also, this screw shaft
On the circumferential surface of 51, a collar member 8 is fixed at a position inside the supporting portion by the bearing 6, and between the collar member 8 and the bearing 6 fixed on the cylindrical portion 1a side. Further, a plurality of disc springs (biasing means) 9 are provided in a compressed state. Then, due to the elastic force of these disc springs 9, the collar members 8 fixed to both end portions of the screw shaft 51 are pressed by the same force toward the center side, that is, toward the support member 2 side. , Which allows the screw shaft 51 to
The reference position shown in FIG. 2 (that is, from the support portion 3 to the both claw members 41, 4
It is urged in such a direction that it always returns to a position where the distances up to 2 are equal).

On the other hand, like the screw shaft 51, the screw shaft 52 also has mutually opposite screw parts (only the screw part 52a is shown here), and both screw parts are screwed to the claw member 43 and a claw member not shown. The chuck body 1 is supported by the same structure as the screw shaft 51.

Next, the operation of this structure will be described. First, the concave portion formed at the end portion of the work W to be processed is brought into contact with the supporting portion 3 so as to match the supporting portion 3 (state shown in FIG. 2), and thereafter,
The entire screw shaft 51 is rotated by rotating the operating portion 7 at one end of the screw shaft 51 with a spanner or the like. By the rotation of the screw shaft 51, the claw members 41, 42 respectively screwed into the screw portions 51a, 51b simultaneously slide in the directions in which they approach each other, and contact the peripheral surface of the work W.

At this time, the screw shaft 51 is held in the reference position by the elastic force of the disc spring 9, and therefore, when the work W has no eccentricity, the screw shaft 51 does not move and the both claw members 41 are not moved. , 42 are pressed against the peripheral surface of the work W with uniform pressure. On the other hand, even when the work W is eccentric, that is, even when the distance from the center point of the work W supported by the support portion 3 to the outer peripheral surface is not constant, the screw shaft 51 and the both-claw members are corresponding to the eccentric amount. By moving 41 and 42 integrally in the direction of the arrow in FIG. 2 against the elastic force of the disc spring 9,
Both claw members 43 are pressed against the work W with a substantially uniform pressure as in the above, and hold the work W. When the claw members 41 and 42 are separated from the work W, the operation portion 7 may be rotated in the opposite direction.

After completing the movement of both claw members 41, 42 in this way,
Similarly, the claw member 43 and a claw member (not shown) are moved by rotating the screw shaft 52, thereby completing the tightening of the work W.

As described above, with this chuck, a pair of claw members corresponding to the respective screw shafts 51, 52 can be moved simultaneously by simply turning one of the operation portions 7 of the screw shafts 51, 52. Accordingly, the screw shafts 51, 52 move against the elastic force of the disc spring 9, so that the work W can be tightened at a substantially uniform pressure. That is, according to this chuck, the shearing force applied to the supporting portion 3 is
Due to the eccentricity, only the elastic force of the disc spring 9 is slightly generated, and the structure can be made extremely advantageous in strength as compared with the conventional chuck.

In the present invention, regardless of the number of claw members, one set or three or more sets of facing claw members may be provided.

[Effect of device]

As described above, according to the present invention, the pair of claw members are brought into contact with and separated from the work piece at the same time by rotation of the screw members having mutually opposite screws. Of the claw member with respect to the support portion, and is biased in the direction of returning to the reference position such that the distance between the pair of claw members and the support portion becomes equal. Therefore, the work piece can always be tightened with a substantially uniform force regardless of its eccentricity, and this has the effect of significantly reducing the shearing force generated in the support portion.

[Brief description of drawings]

FIG. 1 is a half plan view of a chuck of a lathe according to an embodiment of the present invention, and FIG. 2 is a sectional view of the chuck. 1 ... Chuck body, 3 ... Supporting part, 41-43 ... Claw member, 51, 52 ... Screw shaft (screw member), 51a, 51b, 52a ... Screw part, 9 ... Disc spring (urging force) Means), 10 ... Sliding bearing.

Claims (1)

[Scope of utility model registration request] 1. A support portion that abuts on the center of an end of a workpiece,
It is configured to be movable in a direction in which the workpiece is brought into contact with and separated from the support portion, and holds the workpiece.
In a chuck of a lathe having at least a pair of facing claw members, screws having mutually opposite directions which penetrate the supporting portion and are respectively engaged with the pair of claw members, and by rotation of the pair of claws A screw member for simultaneously moving the members along the axial direction of the rotation, and this screw member is provided in a portion penetrating the supporting portion, and the screw member is in the same direction as the moving direction of the claw member with respect to the supporting portion. And a biasing means for biasing the screw member in a direction to return the screw member to a reference position where the distance between the pair of claw members and the support portion is equal to each other. Characteristic lathe chuck.