JPS6210022Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a workpiece support device in a machine tool.

Conventionally, a power chuck is a typical chuck used for chuck work on machine tools. Figures 1 and 2 show an example. This type of power chuck is usually fixed to one end of the spindle (main shaft) of a machine tool with a bolt or the like, and the draw tube 2 is connected to a connector inserted into the spindle. It is connected to a piston rod of a cylinder (not shown) provided at the other end of the spindle via a bearing rod (not shown).

When the draw tube 2 is pulled in the direction of arrow _A1 by the cylinder, the crank lever 4 moves around the pin 5 because one end of the crank lever 4 is in contact with the floating cam 3 attached to the draw tube 2. Rotate clockwise. Then, the master jaw 6 and chuck pawl 7 connected to the other end of the crank lever 4 slide toward the axis of the chuck body 1, thereby being supported by the head center 8 and a tail center (not shown). It is for clamping the workpiece W.

However, in such conventional power chucks, the master jaw 6 is guided by slide grooves formed radially in the chuck body and slides during clamping and unclamping, so wear of both of them is reduced. unavoidable,
If this causes looseness, the workpiece may lift or shake during clamping, reducing machining accuracy. As shown in FIG. 1, these problems tend to become a problem when a part of the workpiece W has an asymmetrical protrusion _W1 , such as a sector shaft for a vehicle. In addition, the conventional power chucks mentioned above are generally heavy, weighing over 40 kg, although this varies depending on the workpiece, and it is extremely troublesome to handle them when removing the chuck to correct the problems mentioned above. The disadvantage is that it requires a large amount of repair work.

In view of the above-mentioned points, the purpose of this invention is to provide a so-called chuck-type workpiece support device in place of the chuck-type one, paying particular attention to the uniqueness of the workpiece. In the invention, the work support device is composed of a main body and
a draw tube disposed at the rear end of the main body and reciprocated with respect to the main body by a predetermined driving means;
A head center is provided at the center of the main body and rotates in response to the reciprocating movement of the draw tube; It is composed of a large number of drive pins that protrude and retract from one end surface of the main body according to the movement. When the drive pin comes into contact with the side surface of the protrusion of the workpiece in the process of protruding from the main body, it stops at that contact position, and one of the remaining drive pins contacts the end surface of the protrusion of the workpiece, causing a connection between the main body and the workpiece. This prevents relative rotation.

Next, one embodiment of this invention will be described in detail with reference to the drawings regarding a workpiece support device in which the aforementioned vehicle sector shaft is used as a workpiece to be machined.
The sector shaft for a vehicle referred to herein is a part of a steering device of a vehicle, and as described later, a part of the shaft has a fan-shaped protrusion _W1 that is asymmetrical with respect to its axis. (hereinafter, this sector shaft will simply be referred to as the work).

In FIGS. 3 to 5, reference numeral 10 denotes a main body that is fixed to the spindle of the machine tool described above by a bolt (not shown), and a rotatable head center is provided in the center of the main body 10 so as to pass through the main body. 1
1 is arranged. 12 is a draw tube disposed concentrically at the rear end of the main body 10;
This draw tube 12 is connected to a cylinder (not shown) which is a driving source through a connecting rod inserted into the spindle, and thereby the main body 1
It is designed to move relative to 0. A groove cam 13 having a phase of 90 degrees in the circumferential direction is formed in the draw tube 12, and a lead pin 14 protruding from the rear end of the head center 11 is engaged with the groove cam 13. and,
The head center 11 rotates when the draw tube 12 moves relative to the main body 10.

Further, in the main body 10, a large number (8 in this embodiment) of drive pins 15 are arranged at equal pitches so as to surround the head center 11. These drive pins 15 are inserted into guide holes 16 so that their tips protrude toward one end of the main body 10.
It is supported so that it can be slid into. moreover,
The rear ends of the drive pins 15 are respectively inserted into the flange portions 12a of the draw tube 12 and connected with nuts 17. Each drive pin 15 is connected to A ₂ by a coil spring 18 interposed between it and the flange portion 12a.
However, as will be described later, when the draw tube 12 is pulled in the _A1 direction, each drive pin 15 moves simultaneously in the _A1 direction against the coil spring 18. .

Next, the operation of the above configuration will be described.

First, when the workpiece W is not supported, the draw tube 12 is pulled to the left (in the _A1 direction) by a cylinder not shown, so each drive pin 15 is in a retracted position with respect to the main body 10. It does not protrude from one end of the main body 10.

In this state, when the workpiece W is supplied between the head center 11 and the tail center 20 by a gripper device (not shown), the tail center 20 moves forward and supports the workpiece W between the tail center 20 and the head center 11. . Next, after the tail center has completed its forward movement, the gripper device is moved back and the draw tube 12 is moved forward in the _A2 direction by the operation of a cylinder (not shown). As the draw tube 12 moves forward, each drive pin 15 advances simultaneously and protrudes from one end of the main body 10, and at the same time, the lead pin 14 moves along the groove cam 13, causing the head center 11 to rotate, thereby moving the workpiece W. It also rotates.

At this time, all the drive pins 15 protrude from one end surface of the main body 10 at the same time, but since a fan-shaped protrusion W ₁ exists in a part of the workpiece W, this protrusion W ₁
The drive pin 15 whose tip is in contact with the side surface of the drive pin 15 stops when it comes into contact with the protrusion _W1 , and the other drive pins 15 advance to the most advanced position in the _A2 direction, and then advance to their most advanced position. The protrusion W ₁ of the workpiece W is formed on the circumferential surface of one of the drive pins 15
The end faces of the two will come into contact with each other.

That is, due to the action of the coil spring 18, all the drive pins 15 other than the drive pin in contact with the protrusion _W1 of the workpiece W move forward to the most advanced position, and at the same time, the workpiece W passes through the head center 11.
As the drive pin 15 is rotated, the end surface of the protrusion W ₁ comes into contact with one of the circumferential surfaces of the drive pin 15 that has advanced to the most forward position, and the workpiece W and the head center 11
Otherwise, relative rotation with the main body 10 will be prevented.

Then, when the spindle is rotationally driven,
The workpiece W rotates together with the main body 10 while being supported by the head center 11 and the tail center 20, and cutting is performed by the cutting tool 21 with the head center 11 and the tail center 20 as references. In other words, according to this embodiment, the protrusion W ₁ of the workpiece W acts as a so-called burr, while the drive pin 15 that comes into contact with this protrusion W ₁
will act as a so-called turning money.

Thereafter, when the cutting process using the bit 21 is completed, the workpiece W is gripped by the gripper device described above and ejected, and the drive pins 15 are all retracted to the most retracted position by the operation of the draw tube 12 to return to the initial state. Return.

In the above-mentioned embodiments, the case where the workpiece to be machined is a sector shaft for a vehicle has been described, but it goes without saying that the present invention is not limited to the workpiece support device for machining the sector shaft.

As is clear from the above description, according to this invention, relative rotation between the main body and the workpiece is prevented by pressing one of the drive pins protruding and retracting from the front of the main body against the end face of the workpiece side protrusion, and the spindle By rotating the workpiece using the drive to perform the desired machining, there is no lifting or wobbling of the workpiece due to wear of the slide groove or jaw, which is the case with conventional power chucks, improving machining accuracy. be able to.

In addition, according to the present invention, unlike conventional power chucks, there are no parts that are gripped with large force, so there are fewer failures, and because there are fewer parts, the weight can be reduced to about one-third of that of conventional power chucks. This has the effect of allowing quick and safe work to be done when installing and removing from machines.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a conventional power chuck, Fig. 2 is a right side view of Fig. 1, Fig. 3 is a broken explanatory view showing an embodiment of the work supporting device in this invention, and Fig. 4 is a cross-sectional view showing the structure of a conventional power chuck. FIG. 3 is a full sectional view, and FIG. 5 is a right side view of FIG. 4. 10...Body, 11...Head center, 12...Draw tube, 15...Drive pin, 20...Tail center, W...Work, _W1 ...Protrusion.

Claims (1)

[Scope of utility model registration request] A workpiece support device that performs desired machining by supporting and rotating both ends of a workpiece that has an asymmetrical protrusion on a part of its outer periphery at a head center and a tail center. , a draw tube provided at the rear end of the main body and reciprocated relative to the main body by a predetermined driving means; and a head provided at the center of the main body and rotated in response to the reciprocating movement of the draw tube. A center and a head are disposed parallel to each other in the main body so as to surround the center, and protrude and retract from one end surface of the main body in accordance with the reciprocating movement of the draw tube, and protrude from the workpiece during the process of projecting from the main body. It is equipped with a large number of drive pins that stop at the abutting position when they come into contact with the side surface of the part, and when the drive pins are made to protrude with a workpiece set between the head center and the tail center, the workpiece protrudes. A workpiece support device for a machine tool, characterized in that any of the remaining drive pins other than the drive pin that stops when it comes into contact with the side surface of the protrusion comes into contact with the end surface of the protrusion to prevent relative rotation between the main body and the workpiece. .