JPS6020803A - Center supporting device in headstock moving lathe - Google Patents

Abstract

PURPOSE:To optimize the center supporting thrust so as to enable the work to be quickly fed by a constant thrust and reduce a mechining time, by constituting a device such that a center slide is movably supported by further fixed to a guide bar while the center slide and a headstock are connected to each other through a connecting bar and respectively fixed. CONSTITUTION:The first clamp 31 clamps a guide bar 26 fixing a center slide 21 to the guide bar 26 while the second clamp 32 release a connecting bar 28 placing the center slide 21 and the connecting bar 28 in a relatively movable condition, thus a work 1 is cut by holding it to a main spindle 11. Next, placing a center quill 22 in its retractive condition, the main spindle 11 is moved till an end of the work 1 comes to a predetermined position in relation to the center slide 21, and the work is supported by a center 20 by hydraulically advancing the center quill 22, here the second clamp 32 clamps the connecting bar 28 while the first clamp 31 releases the guide bar, thus supporting the work 1 by the center. By this constitution, the work is supported by the center with a constant thrust and can be quickly fed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a center support device for supporting one end of a workpiece in a lathe in which the headstock moves along with the main spindle in its axial direction.

Conventionally, in the above-mentioned type of NC lathe, the center that supports the other end of the workpiece whose one end is fixed to the main spindle is slidably supported in the axial direction on a center stand fixed on the bed of the lathe, and is supported by an air cylinder or the like. Thrust force was applied to the workpiece using a weight or the like.

In these devices, the center must slide within the center building in conjunction with the movement of the spindle and workpiece while supporting the workpiece at the center, and as a result, the thrust force that the center has to support the workpiece is quite large, and its structure Moreover, the thrust cannot be reduced. Therefore, when processing extremely thin long products, problems such as bending of the workpiece due to the thrust of the center occurred. Also, since the center is involved, rapid forwarding of the workpiece is not possible. That is, as shown in FIG. 1, when processing a round bar workpiece 1 to obtain a product having a thick body 2 at the center and thin parts 3 at both ends, as shown in FIG. At 4, the thin part on the right side 3
After machining, it is desirable to slide the workpiece 1 inside the guide bush 6 and fast-forward it to the right together with the center 5 to reach the state shown in FIG. 3, and then start a new cutting with the cutting tool 7.
If the workpiece 1 is rapidly fed while pushing the center 5 with its thin part 2, there is a risk that the thin part 2 will break or become bent, so it cannot be fed out except by normal cutting feed. For this reason, the conventional apparatus had the disadvantage of requiring a long processing time.

The present invention aims to eliminate the drawbacks of the above-mentioned conventional devices.
To provide a center support device that can always support a workpiece at the center with an optimal thrust suitable for the workpiece, can perform rapid forwarding while keeping the thrust constant, and can shorten machining time. .

A center support device according to the present invention includes a center that can centrally support the other end of a workpiece whose one end is supported by a spindle, a center stand that supports the center so as to be movable in the axial direction, and a center stand that supports the center in the axial direction of the spindle. a first clamp device that fixes the center mount to the kite bar; a connection bar that is arranged parallel to the spindle axis and extends from the headstock to the center mount; The present invention is characterized in that it includes means for fixing to either one of the headstock or the center stock, and a second clamp device for fixing the connecting bar to the other of the headstock or the center stock.

Hereinafter, the present invention will be explained in more detail using embodiments of the present invention shown in FIGS. 4 to 6.

FIG. 4 is a longitudinal cross-sectional view of a main part of a moving headstock type NC lathe equipped with the center support device 1o of the present invention. In the same figure, a headstock 12 (only a portion of which is shown) that rotatably holds the spindle 11 is held in a not-shown portion of the bed 13 so as to be slidable in the axial direction of the spindle, and is also supported by a ball screw. (
(not shown). Main shaft 1
A guide bush 14 is disposed on the same axis in front of the guide bush 1, and the guide bush 14 is connected to a guide bush support 15.
The guide bush support 15 is fitted to the bed 13.
Fixed. The guide bush 14 slidably supports the workpiece 1 supported on the main shaft 11. A tool rest 16 is further provided on the bed 13 so as to be slidable in a direction perpendicular to the main shaft. Although not shown, a turret is provided on the tool rest 16, and a tool attached to the turret is provided near the right side of the guide bush 14 to machine the workpiece 1. Since these are known structures, a detailed explanation will be omitted.

The center support device 10 has a center stand 21 equipped with a center 20 that supports the edge of the workpiece 1. As shown in detail in FIG. 5, the center stand 21 supports a center quill 22 which is movable in the axial direction of the center 20, and the center 20 is held within the center quill 22 so as to be movable in the axial direction. The rear part of the center quill 22 and the inner surface of the center stand 20 constitute a hydraulic cylinder 23, and the center quill 22 reciprocates due to the hydraulic force. A compression coil spring 24 is arranged between the center quill 22 and the center 20.
0 in the direction of protruding from the quill 22. Therefore, the center 20 is normally at the most protruding position from the quill 22, as shown in FIG. 5, and can be retracted into the tile by pushing the center 20 to the right.

Referring again to FIG. 4, the center stand 21 is slidably held by two guide bars 25,26. These guide bars 25 , 26 are fixed to a frame 27 fixed to the bed 13 and are parallel to the axial direction of the main shaft 11 and therefore parallel to the axes of the center 20 and the center quill 22 .

Thus, the center stand 21 is movable in the axial direction of the main shaft 11 and the center 20. Further, below the guide bar 26, a connecting bar 28 parallel to the main shaft axis is arranged so as to be movable in the axial direction.

The left end of the connecting bar 28 is fixed to a bracket 29 fixed to the headstock 12 using a nut 30, so that the connecting bar 28 moves together with the headstock 12. On the other hand, the right end of the connecting bar 28 extends to the center stand 21 and is slidably held by the center stand 21. The center stand 21 further supports a first clamp device 31 for fixing the center stand 21 to the guide bar 26 and a second clamp device 32 for fixing the center stand 21 to the connecting bar 28.

As shown in detail in FIG. 6, the center stand 21 includes a center stand main body 21A holding a center and a center tile, a first block 21B supporting the center stand main body 21A, and a first block 21B that supports the center stand main body 21A.
It consists of a second block 21C fixed to a block 21B, and the first block 21B has bearings at both ends (front and rear of the paper in FIG. 6), and a guide bar 25.26.
and supports the connecting bar 28 in a slidable manner. The first clamp device 31 has a clamp cylinder 33 fixed to the second block 21C and a clamp piece 34 held at the tip of the piston rod.
It has a clamp cylinder 35 fixed to the block 21C and a clamp piece 36 held at the tip of the piston rod. Each clamp cylinder of the first and second clamp devices is controlled by an NC control board (not shown).

Next, the cutting operation by the lathe having the above structure will be explained.

During normal cutting without center support machining, the clamp piece 34 of the first clamp device 31 advances to clamp the guide bar 26, as shown in FIG. 6, and the center stand 21 is fixed to the guide bar 26 and stopped. are doing. On the other hand, the clamp piece 36 of the second clamp device 32 is separated from the connecting bar 28, so that the connecting bar 28 can freely slide relative to the center base 21. In this way, the main spindle 11 holds the workpiece 1 and moves forward while rotating (moves to the right in FIG. 4) to perform cutting, and at this time, in conjunction with the forward movement of the main spindle 11, the connecting bar 28 also moves forward as shown in FIG. Although it moves to the right, there is no problem because the connecting bar 28 can slide relative to the center stand 21.

Next, in order to support the workpiece at the center, the center stand 21 is moved by the first clamping device 31 as described above.
The workpiece 1 is advanced by the main shaft 11 with the second clamping device ft32 in a released state and the center quill 22 in a retracted state. When the tip of the workpiece 1 (the right end in FIG. 4) reaches a predetermined position relative to the center stand 21, the headstock 12 stops moving forward. here,
The above predetermined position is a position where, when the center quill 22 is moved forward from the center stand 21 by hydraulic pressure, the center 20 can move forward several blades after the tip of the center 20 contacts and supports the workpiece 1. be. After stopping the headstock 12, the center quill 22 is hydraulically advanced to support the workpiece 1 at the center 20. Therefore, the workpiece 1 is supported by the center 20 which receives thrust from the compression coil spring 24. Thereafter, the second clamp device 32 is operated to clamp the connecting bar 28 with the clamp piece 36 to fix the center stand 21 to the connecting bar 28, and the first clamp device 31
is released so that the center stand 21 can freely slide relative to the guide bars 25,26. With this, the center support operation is completed. After that, the workpiece 1 is moved between the spindle 11 and the center 20.
The headstock 12 moves forward while being supported at , and cutting is performed. At this time, the center stand 21 is connected to the headstock 12 via a connecting bar 28 and moves in conjunction with the headstock 12, so
The thrust force of the center 20 on the workpiece is always constant regardless of the moving speed of the headstock 12. In addition, since the center 20 is not pushed into the center stand 21 as the workpiece moves, there is no problem even if the thrust to the center 2o is small.

As mentioned above, the thrust of the center 20 is generated by the compression coil spring 24.
Determined by Therefore, by replacing this coil spring, any desired center thrust force can be obtained and the force remains unchanged throughout the center support. Furthermore, an arbitrary center thrust may be obtained by changing the protrusion length of the workpiece and the material feed length without replacing the fill spring 24.

In the above embodiment, the connecting bar 28 is always fixed to the headstock 12, and fixed to the center table 21 by the second clamping device 32, or slidably released, but instead of this, a clamping device is used. Ki is installed on the main M stand 12, and the center stand 21
The connecting rod 28 may be fixed at all times.

As described above, in the present invention, since the headstock and the center stock move in conjunction with each other, the thrust force of the center on the workpiece can be set to a small value appropriate for the workpiece, and moreover, the headstock and the center stock move in conjunction with each other. It does not change even when moving. Therefore, there is no possibility that the workpiece is bent by the thrust of the center, and rapid feeding is also possible without any problem, which has the advantage of significantly improving cutting efficiency.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an example of the workpiece, Figs. 2 and 3 are schematic side views showing the processing procedure of the workpiece shown in Fig. 1, and Fig. 4 is a side view showing an example of the workpiece shown in Fig. 1. 5 is a partial cross-sectional side view of the main part of the center table 21, and FIG. 6 is a sectional view taken along the line A-A in FIG. 4. 1... Workpiece 10... Center support device 11...
Spindle 12... Headstock 13... Bed 14... Guide bush 20...
・Center 21...Center stand 22...Center quill 24...Coil spring 25.26...Guide bar
28... Connecting bar 31... First clamping device 32... Second clamping device Agent Patent attorney Kyo Matsu 3rd figure 1st figure 2nd figure 3rd figure

Claims (1)

[Claims] In a lathe in which the headstock moves in the direction of the spindle axis,
A center that can centrally support the other end of a workpiece whose one end is supported by a spindle, a center stand that supports the center movably in the axial direction, and a guide bar that supports the center stand so that it can move in the axis direction of the spindle. , a first clamp device for fixing the center stock to the guide bar, a connecting bar arranged parallel to the spindle axis and extending from the spindle stock to the center stock;
A spindle joint characterized by comprising means for fixing the connecting bar to either one of the headstock or the center stand, and a second clamp device for fixing the connecting bar to the other of the headstock or the center stand. Center support device for dynamic lathes.