JPH0639038B2 - Indexing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of an indexing device used for a rotary table or the like of a machine tool.

(Prior Art) An indexing mechanism (index positioning mechanism) for rotating a table (turret head) in a rotary table of a machine tool by a predetermined angle is configured by using, for example, a toothless gear, a ratchet wheel, or a Geneva. Has been done.

(Problem of the invention) However, with such a mechanism, the backlash cannot be completely removed and the acceleration is also discontinuous, so that it sufficiently satisfies the requirements in terms of motion characteristics and stopping accuracy (indexing accuracy). I couldn't say that. Further, since the table (turret head) floats up during indexing, there is a problem that a large load is applied to the driving unit.

On the other hand, there is an indexing device that performs indexing and clamping operations using a hydraulic mechanism, but it is inevitable that the device will become large due to its complicated structure.

Therefore, in view of these problems, the present applicant has previously proposed in Japanese Patent Application No. 62-232866 an indexing device that does not lift a table, which is provided with an indexing mechanism by a roller gear cam and a clap mechanism by a curvic coupling. Although proposed, the present invention aims to provide an indexing device having a simple structure, a compact outer shape, and good motion characteristics.

(Means for Achieving the Object) An indexing device of the present invention rotatably supports a rotating shaft of a turret head on a base, and radially installs a plurality of rollers around the rotating shaft. The turret head is driven to rotate intermittently by a predetermined number of indexes by the rotation of the roller gear cam that guides it toward the other side, while a cone with a tapered diameter is formed on the rotating shaft, and the rotating shaft is in close contact with this cone. A clamp having a similar tapered surface for restricting the rotation of the base is fixedly mounted on the base, and is positioned coaxially with the rotating shaft to bias the rotating shaft in the direction of separating the cone and the clamp; A clamp cam that rotates integrally with the roller gear cam and that axially displaces the rotary shaft against the spring; and a clamp cam that is positioned in series with the spring and elastically transmits the clamp force of the clamp cam to the rotary shaft. A disc spring having a spring constant larger than that of the spring.

(Operation) When the roller gear cam rotationally drives the rotary shaft of the turret head through the roller and rotates by a predetermined angle, the clamp cam that rotates integrally with the roller gear cam imparts an elastic clamp force through the disc spring to provide the rotary shaft. Is driven in the axial direction against the coiled spring to bring the cone into close contact with the clamp and lock the rotation of the turret head. By repeating this operation, the turret head intermittently rotates by a constant angle while stopping at a predetermined position.

Since the clamping force of the clamp cam is elastically transmitted to the rotary shaft via the disc spring, wear and dimensional error of the cone and the clamp are compensated, and the cone and the clamp are always brought into close contact with each other with a constant clamping force.

On the other hand, since the coil spring and the disc spring that restrict the displacement of the rotary shaft are located in series on the rotary shaft, the device is downsized.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a turret head, and 2 is a rotating shaft of the turret head 1. The rotary shaft 2 freely rotatably projects from a base 3 provided at the rear of the turret head 1 and joins the turret head 1 to the tip portion.

At the tip of the turret head 1 of the rotary shaft 2 which is connected to the turret head 1, there is formed a cone 7 having a diameter that is tapered rearward. On the other hand, a mortar-shaped clamp 8 symmetrical to the cone 7 is fixed to the base 3 so as to face the cone 7 and surround the rotary shaft 2.

A plurality of rollers 4 are radially mounted on the outer periphery of the rotary shaft 2 inside the base 3 as shown in FIG.
A roller gear cam 5 that engages with and rotates the rotary shaft 2 by a predetermined angle is housed inside the base 3. The roller gear cam 5 is fixed to a drive shaft 6 orthogonal to the rotary shaft 2, and a meandering lead (not shown) is formed on the outer periphery of the roller gear cam in the circumferential direction so as to guide the roller 4 sideways while rotating the roller 4.

The diameter of the rotary shaft 2 is reduced behind the roller 4, and a shifter 9 having a flange-shaped outer shape is slidably fitted on the outer side of the rotary shaft 2. A nut 12 is screwed onto the rotary shaft 2 behind the shifter 9, and a holder 13 fastened to the nut 12 holds the shifter 9 in contact with the large diameter portion of the front rotary shaft 2 via a disc spring 14. .

The rear end of the rotary shaft 2 is supported by the base 3 via a bearing 15. Then, the rotary shaft 2 is moved forward between the bearing 15 and the holder 13, that is, the cone 7 is clamped 8
Coiled spring 1 that urges it away from
6 is interposed. The spring 16 and the bearing 1
A thrust bearing 17 is interposed between the thrust bearing 17 and the bearing 5.

On the other hand, a lever 10 is provided inside the base 3 to drive the shifter 9 in the axial direction. One end of the lever 10 is attached to the base 3 via a pin 11 so as to be freely rotatable in the front-rear direction, and the flange portion 9 of the shifter 9 is provided at an intermediate portion of the lever 10.
A protrusion 10A that abuts A is formed. A plate-shaped clamp cam 18 integrally fixed to the drive shaft 6 of the roller gear cam 5 comes into contact with the other end of the lever 10 from the front.

The clamp cam 18 has the roller gear cam 5 and the roller 4
The lever 10 is formed in an elliptical shape corresponding to the meandering of the lead of the roller gear cam 5 so that the lever 10 is rotated rearward with the pin 11 as a fulcrum by rotating the rotary shaft 2 through a predetermined angle.

Next, the operation will be described.

In the stationary state, the clamp cam 18 abuts the elliptical projection on the lever 10 and tilts the lever 10 backward to displace the rotary shaft 2 backward through the shifter 9, so that the cone 7 clamps. 8, and the rotation of the turret head 1 is locked. On the other hand, the lead of the roller gear cam 5 that guides the roller 4 is parallel to the rotation direction, that is, the roller 4 is not driven in any direction.

In the case of a rotary table for machining a workpiece, the workpiece on the turret head 1 is machined in this stopped state.
Since the clamp 8 and the clamp 8 are in close contact with each other, a sufficient restraining force for holding the turret head 1 at the stop position can be obtained. Therefore, there is no fear that the turret head 1 will sway or rotate due to the axial and rotational forces transmitted from the processing machine through the workpiece.

On the other hand, when the drive shaft 6 is rotated, the clamp cam 18
Is retracted from the contact portion with the lever 10, and the rotary shaft 2 urged by the spring 16 via the holder 13 causes the shifter 9 to move.
Along with that, it is displaced forward. As a result, the cone 7 is separated from the clamp 8 and the constraint of the rotary shaft 2 is released, and at the same time, the rotating roller gear cam 5 leads to the next roller 4
And guides it laterally, and the rotary shaft 2 starts to rotate together with the turret head 1. It should be noted that the lever 10 also rotates forward along with the backward movement of the clamp cam 18 as the shifter 9 is displaced forward.

When the rotating shaft 2 rotates by a predetermined angle, the reed becomes parallel to the rotating direction of the roller gear cam 5 again, and the lateral displacement of the roller 4 stops. At the same time, the rotating clamp cam 18 causes the protruding portion to move again to the lever 10. The lever 10 is contacted and the lever 10 is tilted backward, and the rotary shaft 2 is retracted. As a result, the cone 7 comes into close contact with the clamp 8 and the rotational displacement of the rotary shaft 2 is locked by frictional resistance.

When the cone 7 comes into close contact with the clamp 8 and the rotary shaft 2 moves to a position where axial displacement is restricted before the most protruding portion of the clamp cam 18 comes into contact with the lever 10, the lever 10 that continues to tilt is a disc spring. Only the shifter 9 is retracted while deforming 14, and the cone 7 and the clamp 8 are reliably brought into close contact with each other based on the elastic biasing force of the disc spring 14.

In this way, the roller gear cam 5 becomes the turret head 1.
The rotational driving and the positioning of the turret head 1 are performed by the clamp cam 18 holding the turret head 1 at the positioning position.
The turret head 1 repeats rotation and stop with high accuracy in a constant cycle.

If the cone 7 is very slightly separated from the clamp 8, the rotary shaft 2 can rotate, so that the axial displacement of the rotary shaft 2 by the clamp cam 18 can be very small. Therefore, the floating of the turret head 1 at the time of rotation can be minimized, and the operation of the turret head 1 can be smoothly performed even at high speed rotation.

By the way, the cone 7 and the clamp 8 that lock the rotation of the turret head 1 by frictional force wear with each other as they are used. However, in this case, the disc spring 14 further separates the shifter 9 from the holder 13 to increase the rearward displacement of the rotary shaft 2 with respect to the rearward tilt of the lever 10 and to ensure the close contact between the cone 7 and the clamp 8. Even when 7 and the clamp 8 are worn, there is no possibility that the holding force of the turret head 1 at the stop position is reduced.

(Effects of the Invention) As described above, according to the present invention, the cone formed on the rotary shaft is brought into close contact with the clamp fixed to the base to hold the turret head at the stop position by this frictional force, so that sufficient holding force can be obtained. On the other hand, when the turret head is rotated, the constraint of the turret head can be released only by slightly separating the cone from the clamp, so that the lifting of the turret head during the rotation can be minimized. Therefore, even in high-speed indexing, smooth and accurate rotation and stop can be performed, and the stop mechanism by the cone and the clamp has a simple structure and the entire device can be compactly housed.

Further, since a disc spring having a spring constant larger than that of a coiled spring is interposed between the rotary shaft and the clamp cam that drives the rotary shaft in an axial direction, the clamping force is elastically exerted, so that the cone and the clamp are clamped. It is possible to always exhibit good clamping performance regardless of wear and dimensional error between and. Further, since the clamping force is stable, the required power can be made constant and the clamping force can be adjusted only by replacing the disc spring. Further, since the coiled spring and the disc spring are provided in series on the rotary shaft, the device can be downsized.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an indexing device showing an embodiment of the present invention, and FIG. 2 is a transverse sectional view of the same. 1 ... Turret head, 2 ... Rotation axis, 3 ... Base, 4
...... Roller, 5 ...... Roller gear cam, 7 ...... Cone, 8
...... Clamp, 14 ...... Disc spring, 16 ...... Coil spring, 18 ...... Clamp cam.

Claims (1)

[Claims] 1. A turret head is rotatably supported on a base of a turret head, a plurality of rollers are radially mounted around the rotary shaft, and a turret head is fixed by rotation of a roller gear cam which guides the rollers laterally. While it is driven to rotate intermittently by the index number of, a cone with a tapered diameter is formed on the rotating shaft, and a similar tapered surface that closely adheres to this cone and regulates the rotation of the rotating shaft is provided. A clamp is fixed to the base, and a coil-shaped spring that is positioned coaxially with the rotating shaft and urges the rotating shaft in the direction of separating the cone and the clamp,
A clamp cam that rotates integrally with the roller gear cam and axially displaces the rotary shaft against the spring; and a clamp cam that is positioned in series with the spring and elastically transmits the clamp force of the clamp cam to the rotary shaft. An indexing device comprising: a disc spring having a spring constant larger than that of a spring.