JPH0131365Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is attached to an auxiliary chuck for a lathe, more specifically, to a three-jaw or four-jaw main chuck of a lathe, so that it can firmly hold the workpiece from the inside diameter side. This concerns the auxiliary chuck.

Three-jaw chucks and four-jaw chucks are used to chuck the workpiece on NC lathes, but these chucks have a structure in which the outer periphery of the workpiece is gripped by claws that gather toward the center. .

By the way, in NC lathe processing, when cutting a disc-shaped workpiece that has a through hole in the center and has thin walls on both sides of the outer periphery as a gear material,
Since the workpiece is chucked at the outer periphery, the claws that grip the outer periphery get in the way of cutting, and when cutting both sides, it is necessary to change the workpiece, which significantly increases the number of machining steps. There is a problem in that processing costs are high.

In addition, there is a problem in that a large amount of modification costs are required to modify the chuck of an existing NC lathe equipped with a jaw chuck to a structure that allows chucks on the workpiece from the inside diameter.

This idea was made to solve the above problems, and it is possible to chuck the workpiece from the inner diameter side by using the existing chuck as is, and it is possible to chuck the workpiece from both sides to the outer circumference. The purpose is to provide an auxiliary chuck that can perform the processing in two steps.

In order to achieve the above-mentioned purpose, this invention has a holder attached to the main chuck of a lathe, which has a plurality of claws arranged on the front so that they can be assembled and separated about the axis, and a holder coaxially mounted on the front of the main chuck. The holder is fixed in a central arrangement, and has a shaft that penetrates the holder so as to be movable in the axial direction along the axis of the holder, and a shaft that is fitted onto the distal end of the shaft and attached to the holder. A cylindrical chucking member that is fixed and whose tip is divided into a plurality of parts by an axial slit is attached, a tapered member is attached to a position corresponding to the tip of the pawl on the main chuck of the shaft body, and a tapered member is attached to the tip of the pawl of the main chuck. , forming a tapered surface that slides in contact with the tapered surface of the tapered member to convert the movement of the pawl into an axial movement of the shaft, and at the tip of the shaft and the chucking member, the outer diameter of the chucking member is changed by the movement of the shaft. The structure includes a sliding tapered surface that changes the angle.

This invention will be explained below based on the embodiments shown in the accompanying drawings.

As shown in the diagram, the main chuck 1 on the NC lathe
is formed by attaching a plurality of claws 3 to the front surface of the main body 2 in a radial arrangement so that they can be assembled and separated freely,
It is designed to rotate around its axis.

1 and 2 show a first example of an auxiliary chuck 11 attached to the main chuck 1. FIG.

1 and 2, a disc-shaped holder 12 is fixed with bolts 13 in a coaxial arrangement to the front surface of the main body 2 of the main chuck 1, and this holder 1
2 holds a shaft body 14 which is coaxial with the main chuck 1 so as to be movable in the axial direction.

A tapered member 15 is fitted onto the shaft 14 at a position where the tip of the pawl 3 faces in the middle, and a hard elastic body 17 is inserted between the taper member 15 and a nut 16 screwed onto the rear end of the shaft 14. The tapered member 15 moves integrally with respect to the shaft body 14 on the front end side, and moves on the rear end side via the elastic body 17.

The tapered member 15 has a tapered surface 15a on the front side.
The tip of the claw 3 is provided with a tapered surface 3a that makes sliding contact with the tapered surface 15a, and when the claw 3 moves collectively, the tapered surface 3a of the claw 3 slides on the tapered surface 15a of the tapered member 15. Taper member 1
5 moves backward to draw the shaft 14 into the main body 2.

A cylindrical chucking member 18 threadably connected to the front surface of the holder 12 is fitted onto the front half of the shaft body 14, and the tip of the chucking member 18 is fitted into a small diameter portion 19 that fits into the inner peripheral hole B of the workpiece A. The middle portion from the tip is divided by a plurality of slits 20 formed along the axial direction so that the diameter can be expanded.

The shaft body 14 is biased with elasticity in the direction of constant forward movement toward the tip end by a spring 21 contracted inside the chucking member 18, and the cone member 22 attached to the tip end of the shaft body 14 has a small diameter in the chucking member 18. A tapered surface 19 located inside the portion 19, where the inner periphery of the cone member 22 and the small diameter portion 19 are in sliding pressure contact with each other.
a and 22a, and when the shaft body 14 is retracted by a set of pawls 3, the small diameter portion 19 expands in diameter and chucks the workpiece A in the inner circumferential hole B.

Note that the difference between the movement of the claw 3 and the amount of diameter expansion of the small diameter portion 19 is absorbed by the contraction of the elastic body 17.

FIG. 3 shows a second example of the auxiliary chuck 11, in which the diameter of the small diameter portion 19 is expanded by pushing out the shaft body 14 with the claw 3. The same parts as those in Example 1 will be given the same reference numerals, and only the differences will be explained in detail instead of being explained.

In FIG. 3, a tapered surface 15a is formed on the rear surface of a tapered member 15 that is externally fitted onto the shaft 14, and the rear surface of the tapered member 15 is supported by a nut 16 screwed onto the rear end of the shaft 14. An elastic body 17 is placed between the step provided in the middle of the body 14 and the front surface of the tapered member 15.
is arranged, and the shaft body 14 moves forward toward the distal end side via the tapered member 15 and the elastic body 17 due to the collective movement of the claws 3.

A spring 21 is compressed inside the chucking member 18 to constantly press the shaft body 14 backward, and a small diameter shaft 2 connected from the tip of the shaft body 14 is connected to the inside of the small diameter portion 19.
3 is fitted, and a sharp tapered surface 2 is formed at the tip of the small diameter shaft 23.
3a and a tapered surface 19a is provided on the inner surface of the small diameter portion 19, and when the shaft body 14 moves forward, the small diameter portion 19 expands in diameter and chucks the workpiece A.

The auxiliary chuck of this invention has the above-mentioned structure, and has an inner circumferential hole B as shown in Figs. 1 and 3, and requires processing to become thinner from both sides to the outer periphery. Used when cutting workpiece A with an NC lathe.

The auxiliary chuck 11 has a holder 12 fixed to the main chuck 1 body 2 with bolts 13, a shaft body 14 arranged coaxially with the main chuck 1, and a tapered member 15.
Set it so that it faces claw 3.

In this state, the small diameter portion 19 of the chucking member 18
The workpiece A is fitted onto the main chuck 1, and the claws 3 of the main chuck 1 are moved together.

When the claws 3 are assembled, the shaft body 14 is retracted in the case of FIG. 1 and pushed out in the case of FIG. 3, and the small diameter portion 19 at the tip of the chucking member 18 expands in diameter, chucking the workpiece A with the inner diameter portion.

In this state, rotate the main chuck 1 and use the blade attached to the tool post to cut the workpiece A from one side. After cutting, reverse the direction of the workpiece A and start cutting from the other side. Do this.

Note that the workpiece A can be removed by opening the claws 3 of the main chuck 1, and the shaft body 14 moves under the pressure of the spring 21, and the small diameter portion 1 of the chucking member 18 moves.
9 will be reduced in diameter.

As described above, according to this invention, the shaft body is moved in a direction perpendicular to the jaws by the claws of the main chuck, and the diameter of the divided tip of the chucking member into which the workpiece is externally inserted is enlarged by the movement of the shaft body. By attaching it to the jaw chuck of an existing lathe, the workpiece can be chucked and rotated from the inner circumference side, and there is no need to modify the existing lathe. Inner periphery gripping can be achieved with a small equipment cost.

In addition, since the inner periphery of the workpiece can be gripped using the claw chuck, the workpiece can be efficiently cut from both sides, and costs can be reduced by reducing the number of processing steps.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a first example of an auxiliary chuck according to the invention in a state of use, FIG. 2 is a front view of the same, and FIG. 3 is a longitudinal cross-sectional view showing a second example of the same. 1 is the main chuck, 2 is the main body, 3 is the claw, 11 is the auxiliary chuck, 12 is the holder, 14 is the shaft body, 15
1 is a tapered member, 18 is a chucking member, 19 is a small diameter portion, and 19a and 22a are tapered surfaces.

Claims (1)

[Scope of utility model registration request] A holder is fixed to a main chuck of a lathe in which a plurality of claws are arranged on the front surface so that they can be assembled and separated from each other with respect to the axis, and are arranged coaxially on the front surface of this main chuck, and to the holder, A shaft that passes through the holder so that it can move freely in the axial direction along the axis of the holder, and a cylinder that is fixed to the holder by being fitted onto the tip of the shaft and whose tip is divided into multiple parts by axial slits. A chucking member of the shape of a shape is attached, and a tapered member is attached to a position corresponding to the tip of the pawl on the main chuck of the shaft body, and the tip of the pawl of the main chuck slides into contact with the tapered surface of the taper member to control the movement of the pawl. An auxiliary chuck for a lathe, which forms a tapered surface that converts the motion in the axial direction of the shaft, and has sliding tapered surfaces at the tips of the shaft and chucking member that change the outer diameter of the chucking member as the shaft moves. .