JPH031154Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a rest device used for cutting a long workpiece having a complicated step shape, such as a crankshaft.

(Prior art) For example, when cutting the outer diameter of a crankshaft pin, normally, as shown in Fig. 5, after clamping the shaft parts a, a at both ends, the rest device C shown in Fig. 6 is used. Although the pins are moved forward to be machined, when cutting the pins b and b that are farther away from the shaft parts a and a, the workpiece part escapes in the direction of the arrow in the figure due to the load during cutting. Therefore, not only is it not possible to accurately cut the part to be cut with sufficient roundness, but there are also problems in that chatter is more likely to occur.

(Purpose) This invention was made in view of the above problems.
The purpose is to provide a new rest device that can always firmly hold the cutting part regardless of changes in the outer diameter.

(Means for Achieving the Object) That is, in order to achieve the above object, the present invention includes a rest main body that moves forward by being driven by a drive mechanism, a roller at the front end, and a spring that moves the rest main body forward and backward. The center guide is arranged so that it can swing around a shaft provided on both sides of the rest body in contact with a part of the center guide, and at least the part outside the radius of the workpiece from the roller circumferential surface of the center guide. A rest device for machining a long workpiece is provided with a pair of arms that support the workpiece from the outside by rollers provided in the workpiece.

(Example) The details of the present invention will be explained below based on the illustrated example.

1 to 4 show an embodiment of the present invention, and reference numeral 1 in the figures indicates a rest guide 3 (fourth
The rest body is slidably attached to the turret (see Fig.) and moves forward and backward toward the tool post 5 by being driven by the hydraulic cylinder 4. Two branch parts 11, 11 with a rather wide interval are integrally molded in a U-shape. In each of these branch parts 11, 11, a groove 12 is formed in the axial direction from the tip thereof, as shown in FIG. Rest arms 13, 13 that rotate within the same plane are attached with pins 14, 14. These rest arms 13, 13 have a function of holding the workpiece at three points in cooperation with a center guide 22, which will be described later.
The shafts 16, 16, which are inserted into the tip of each arm at a distance from the circumferential surface of the roller 25 of No. 2 at least equivalent to the radius of the cut portion W, are rotatable in contact with the circumferential surface of the cut portion W. Rollers 15, 15 are pivotally supported, and the arm 13 is mounted on the inner side of the rear end of the rest arm 13 to follow the axial displacement of the center guide 22.
The piece 16 that determines the rotation angle of the piece 16 can be adjusted with a screw 18 through an adjustment plate member 19 in between so that the tapered surface 17 provided on the front side of the piece 16 contacts the rear end of the center guide 22. installed.

On the other hand, a rod portion 23 of a center guide 22 disposed between the branch portions 11 and 11 is slidably inserted into a through hole 20 that passes through the axial center of the rest body 1. By constantly pressing the center guide 22 forward with the coil springs 24 interposed in each step of the section 23,
It is configured to support the circumferential surface of the cut portion W via a roller 25 rotatably supported with a shaft 26 at its front end.

In addition, the reference numeral 27 in the figure is a collar for a stopper attached to the end of the rod portion 23 of the center guide 22 with a nut 28, and the reference numeral 6 in FIG. indicates each byte.

In the apparatus configured as described above, both ends of the crankshaft are now clamped to the chuck of a machine tool, and the central pin part furthest from both ends (pins b and b in Fig. 5, here "workpiece w") is
The crankshaft rotates around the part called First, the carriage 7 is moved forward, and the cutting tool 8 is applied to the surfaces of the pins b, b, that is, the surface of the part to be cut W, to perform rough machining of the forged black surface.

Next, when the rest main body 1 is advanced by the cylinder 4 and the roller 25 of the center guide 22 is pressed against the circumferential surface of the workpiece W, the center guide 22 moves back slightly against the coil spring 24, and at the same time, the rear end By pressing the tapered surface 17 of the piece 16, the arms 13, 13 integrated therewith are respectively rotated in the direction of the arrow in FIG. 4 about the shaft 14 so that their tips point inward.

As a result, the circumferential surface of the workpiece W is firmly supported by the roller 25 of the center guide 22 and the rollers 15, 15 provided on the left and right arms 13, 13 at three points whose center angles are separated by 90 degrees or more. Ru.

Then, as the outer diameter of the cut portion W gradually decreases with cutting, the rest body 1 continues to move forward due to the internal pressure of the cylinder 4, while the center guide 22
moves backward, and the left and right arms 13, 13 further rotate inward as the center guide 22 moves backward, and as a result, the workpiece W is continued to be securely fixed by the three rollers 15, 15, 25. Hold on.
After the cut portion W is finished to a certain size, the carriage 7 and the rest main body 1 are retreated to complete one cycle.

As for the shaft portions a of the crankshaft, pins c and c (FIG. 5) closer to a, since these portions are close to the chuck position, normal cutting is performed without using a rest device.

(Effects) As described above, according to the present invention, the workpiece is supported at three points by the front end of the center guide and the rollers provided on the left and right arms, so the clamping part of the long workpiece is Even when cutting a more distant part, this part can be held securely and highly accurate cutting can be performed.

Furthermore, while the center guide is attached to the main body via a spring so that it can move forward and backward, the left and right arms are attached so that they can slide against a part of this center guide, so you can simply point the rest body toward the workpiece. By simply moving the arms forward, both arms can be swung to firmly hold the workpiece in response to changes in the outside diameter of the workpiece during cutting. A piece with a surface is attached to the inner side of the arm with an adjusting screw member so as to be freely adjustable, and the amount of swing of the arm can be adjusted very easily and accurately.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the main parts of a device constituting an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line B-B in Fig. 1. 4 are views showing the entire structure of the device of the present invention, FIG. 5 is a view showing an example of a workpiece, and FIG. 6 is a view showing an example of a conventional rest device. 1...Rest body, 3...Rest guide, 4...
...Cylinder, 5...Turret, 13...Arm, 1
5...roller, 16...piece, 22...center guide, 25...roller, W...workpiece part.

Claims (1)

[Scope of utility model registration request] Rest main body 1 that moves forward by being driven by a drive mechanism
and a center guide 23 equipped with a roller 25 at the front end and attached to the rest main body 1 via a spring 24 so as to be movable forward and backward, and a bridge member 16 with a tapered surface 17 provided on the inner side of the rear end. It comes into contact with a part of the center guide 23, and when the center guide 23 comes into contact with the workpiece and moves backward, the rollers 15, 15 provided at the tip end hold the workpiece from the outer part beyond its radius. A long workpiece comprising a pair of arms 13, 13 that rotate inwardly toward each other, and an adjustment screw member 18 that adjustably attaches the bridge member 16 to the inner side of the arm 13. processing rest equipment.