JPH0242606B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a chuck that grips a workpiece.

Conventionally, the chuck mechanism installed on the main spindle of a machine tool to grip and release the workpiece includes a link mechanism via a lever and an operation of a hydraulic cylinder directly connected to a chuck operating sleeve in the main spindle. There are some things being done by In the former case, a roller provided on the chuck lever engages with an annular groove on the chuck operation sleeve, and when chucking, the sleeve is moved in the direction of the main shaft axis through a link action. The main shaft bearing is subjected to a load in the thrust direction, and when repeated continuous work is performed for a long time, play in the main shaft bearing occurs, causing heat generation in the main shaft, and bearing accuracy is reduced, affecting product accuracy. In the latter case, changes in machining conditions or environment result in oil temperature changes in the fluid pressure cylinder and heat generated by the cylinder during spindle rotation being transmitted to the spindle, resulting in the same results as in the former.

The object of the present invention is to eliminate these drawbacks and provide a chuck control device that always maintains stable accuracy of the main shaft bearing and improves the accuracy of the product.

Hereinafter, the present invention will be explained based on practical drawings.

1 is a bearing 4 mounted on a headstock 3 on a machine tool bed 2.
The main shaft 5 is rotatably supported through the main shaft 1.
The collet 5 grips the workpiece and the taper surface 1a provided on the inner diameter of the front end of the main shaft 1 engages with the taper surface 5a provided on the outer periphery of the collet 5. grip and release the workpiece. Reference numeral 6 denotes an operating rod fixed to the rear part of the collet 5 and slidably inserted in the axial direction within the main shaft 1, and is used to perform a chucking operation on the workpiece of the collet 5. Reference numeral 7 denotes a pulley provided on the main shaft 1, which is suspended by a pulley on the main shaft drive motor shaft and a belt to transmit power to the main shaft 1. A cylinder case 8 is fixed to the pulley 7 or the rear part of the main shaft 1 and extends in the axial direction of the main shaft, and has a cylinder chamber 8a on the shaft and an annular groove 8b on the outer periphery; 9 is used for releasing the collet 5 with respect to the workpiece; Operation rod 6 against
It is held within the cylinder case 8 by a disc spring in contact with the rear part of the cylinder. 10 is the cylinder case 8
A roller 11 that can freely engage with the circumferential end surface of the annular groove 8b.
A first lever 12 is pivotally mounted on the headstock 3 or the bed 2 and is capable of engaging with the rear end of the operating rod 6, so as to move the operating rod 6 against the disc spring 9. A second lever that presses in the axial direction of the main shaft 1 to release the gripping operation of the collet 5 on the workpiece on the main shaft 1, and is interlocked on the first lever 10 in a direction opposite to the pivoting of the first lever 10. It is pivotably mounted. A piece 13 that can freely engage with the rear end of the operating rod 6 is provided on the second lever 12 and is movable in the axial direction of the main shaft via a screw 14. Position spacing is adjustable. 1
Reference numeral 5 denotes a regulating rod that is fixed to the headstock 3 in parallel with the main shaft 1, and passes through a through hole 10a provided in the side wall of the first lever 10 to regulate the pivoting of the first lever 10. A compression spring 18 is disposed on the first lever 15 and biases the first lever 10 against the grasping operation of the collet 5 against the workpiece, between the first lever 10 and nuts 16 and 17 which are screwed so as to be adjustable. is intervening. When a workpiece is gripped by the collet 5, the roller 11 on the first lever 10 is released from engagement with the annular groove 8b of the cylinder case 8 via the compression spring 18. Reference numeral 19 denotes a fluid pressure cylinder coaxially mounted on the shaft on which the first lever 10 is pivoted, and a piston rod 20 within the fluid pressure cylinder 19 is connected to the second lever 12.

Next, the functions and effects of the present invention will be explained.

The workpiece gripping operation by the collet 5 is performed through the action of a disc spring 9. The operating rod 6 pulls the collet 5 in the axial direction of the main shaft 1 against the spring force of the collet 5 via the disc spring 9, and this tension causes the tapered surface 5a of the collet 5 to move toward the main shaft 1.
It tightens under the regulation of the tapered surface 1a and grips the workpiece. Conversely, releasing the workpiece from the grip of the collet 5 is accomplished through operation of the lever mechanism of the present invention. Specifically, the fluid pressure cylinder 19
When the piston rod 20 moves forward, the second lever 12 pivots in the direction of the arrow shown in FIG. In conjunction with the pivoting of the second lever 12, the first lever 10 pivots against the compression spring 18 in a direction opposite to the pivoting of the second lever 12, and the second lever 12 pivots against the disc spring 9. At the same time, the first lever 10 engages with one circumferential end surface of the annular groove 8b of the cylinder case 8 located in the grip operation direction. 8b, the nut 17 on the adjusting rod 15 prevents the first lever 10 from pivoting, and only the second lever 12 continues to pivot and the operating rod 6
When the user continues to press , the tapered surface 5a of the collet 5 is released under the regulation of the tapered surface 1a of the spindle 1 through the action of the spring of the collet 5, and is loosened to release the grip on the workpiece.

From the above, in the present invention, by minimizing the load on the main shaft bearing caused by the thrust load associated with the operation of releasing the grip of the collet, it is possible to not only maintain the accuracy of the main shaft bearing but also to prevent heat generation in the main shaft. The stable rotation of the spindle enables cutting, which can be expected to improve product precision.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a partially cross-sectional side view showing essential parts of the present invention. 1...Main shaft, 5...Collection, 6...Operation rod,
9... Belleville spring, 10... First lever, 12... Second lever, 19... Fluid pressure cylinder.

Claims (1)

[Claims] 1. The workpiece is gripped through the operation of the operation rod 6 which is biased by a disc spring 9 held on the rear shaft of the main spindle 1 and slidably inserted in the axial direction of the main spindle 1. a lever 12 whose one end is freely engageable with the rod 6 and which presses the operating rod 6 in the direction of the main axis against the disc spring 9;
In the chucking device of the collet 5, which releases the grip on the workpiece through the operation of the collet 5, the operating rod 6 is pivotably moved against the disc spring 9 via a hydraulic cylinder 19 pivotally mounted on the bed 2. a second lever 12 that presses forward the rear part of the main shaft 1; and a roller 11 that is pivotally connected to the second lever 12 and can freely engage with the circumferential end surface of the annular groove 8b on the cylinder case 8 at the rear of the main shaft 1.
The first lever 10 has a first lever 10 at one end and the other end is pivoted coaxially with the pivot shaft of the fluid cylinder 19, and one end is fixed to the head stock 3 and passes through the side wall of the first lever 10 and is screwed forward. A chuck control device consisting of a nut 16 that attaches to the chuck and a regulating rod 15 that clamps the first lever 10 via a compression spring 18 that is interposed at the rear.