JPH0529575Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a minute rotary table driving device for precisely positioning a rotary table.

(Prior art and problems) FIG. 3 shows a first conventional example of a rotary table drive device, in which a support shaft 2 is attached and fixed to a rotary table 1.
is rotatably supported by the bearing 3, and the support shaft 2
This is a direct drive system in which the motor is directly connected to the motor 4. In this case, it is not possible to obtain a very small number of divisions for the rotary table rotation angle, and the heat generated by the motor is likely to be transmitted to the rotary table side. Further, there is a problem that the height dimension H becomes large.

FIG. 4 shows a second conventional example of a rotary table drive device, which uses a gear drive system in which a rotary table 1 and a motor 4 are connected via a worm gear 5. In this case, there is a problem that crashes occur.

FIG. 5 shows a third conventional example of a rotary table driving device, in which a gear 6A is formed on the lower surface of the rotary table 1, and the gear 6A is mounted on a support shaft 8 supported by a bearing 7.
A gear 6B that meshes with the support shaft 8 is mounted and fixed.
This is a gear positioning system in which a motor 4 is connected to the In this case, a mechanism for raising and lowering the rotary table 1 as shown by arrows P and Q is required, which causes the problem that the table becomes larger.

(Means for Solving the Problems) In view of the above-mentioned points, the present invention aims to provide a micro-rotary table driving device that has high precision, high resolution, and is free from bumps.

The micro rotary table drive device of the present invention has a ball screw shaft directly connected to the rotary shaft of a motor fixedly attached to a base, or the rotary shaft itself constitutes a ball screw shaft, and is rotatably supported on the base. The ball screw shaft is disposed in a plane perpendicular to the rotation center axis direction of the rotary table, and a ball screw nut screwed onto the ball screw shaft is attached and fixed to the outer periphery of the rotary table. There is. Changes in the position of the ball screw nut due to rotation of the rotary table are followed by elastic deflection of the ball screw shaft.

(Function) In the micro-rotary table drive device of the present invention, the motor is securely fixed to the base, and its rotating shaft (and ball screw shaft) is prevented from rattling in both the radial and axial directions by bearings. can be supported. Further, the rotary table can be rotatably supported with respect to the base without rattling. Furthermore, the ball screw nut, which is screwed onto the motor side ball screw shaft and fixed to the rotary table, has a buckle-less structure that can be screwed onto the ball screw shaft to prevent buckling. , it is possible to prevent the occurrence of backlash and to enable high-precision, high-resolution positioning.

(Example) Hereinafter, an example of the micro rotary table driving device according to the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 10 denotes a base, and the motor 4 is mounted and fixed onto the base 10 via a support member 11. The rotating shaft 12 of the motor 4 is supported by a bearing 13 so as not to play in the radial and axial directions. The ball screw shaft 14 is directly connected to the motor rotation shaft 12 or is constituted by the rotation shaft itself.

On the other hand, a fixed support shaft 15 is fixed on the base 10, and the rotary table 1 is rotatably attached to the fixed support shaft 15 via a rotation guide 16 without wobbling. A nut mounting plate 18 is fixed to the outer periphery of the rotary table 1, and a ball screw nut 17 is fixed to the nut mounting plate 18.
is installed and fixed. The ball screw nut 17
is screwed onto the ball screw shaft 14. Here, the ball screw nut 17 has a backlash-less structure that includes two nuts and a built-in spring that biases the nut, and when it is screwed onto the ball screw shaft 14, no backlash or backlash occurs. It's becoming like that.

Note that the ball screw shaft 14 is disposed within a plane perpendicular to the rotation center axis direction of the rotary table 1.

In the above configuration, on the rotary table 1,
A workpiece that requires precision machining is fixed, and the rotational position of the workpiece is determined by rotating the motor 4 at a predetermined angle (or a predetermined number of rotations) and screwing it into the ball screw shaft 14. This is carried out by moving the ball screw nut 17 and rotating the rotary table 1. Here, when the rotation angle of the rotary table 1 is zero, the central axes of the ball screw shaft 14 and the ball screw nut 17 are the same as those of the rotary table 1.
When the ball screw nut 17 moves from a state parallel to the tangential direction (center axis S) due to rotation of the ball screw shaft 14, the center axis of the ball screw nut 17 becomes, for example, a straight line R in FIG. 1, and the original ball screw Although it deviates from the central axis S of the shaft 14 by an angle φ, the ball screw shaft 14 is made thinner and has elasticity, so that the ball screw shaft 14 is deflected to follow this deviation.

(Effects of the invention) As explained above, according to the micro rotary table driving device of the present invention, the ball screw shaft can be directly connected to the rotating shaft of the motor fixedly attached to the base, or the ball screw shaft can be connected directly to the rotating shaft of the motor fixed to the base. A ball screw nut screwed onto the ball screw shaft is mounted and fixed on a rotary table rotatably supported by the base, and the elasticity of the ball screw shaft is adjusted against changes in the position of the ball screw nut. Since the configuration is such that the deflection is followed by the deflection caused by the bending, the deflection can be eliminated with a simple configuration. As a result, it is possible to obtain a device that can perform positioning with high resolution and high precision (on the order of 0.1μ).

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the micro rotary table driving device according to the present invention, FIG. 2 is a sectional view of the same side,
Figure 3 shows the first rotary table drive device of the conventional rotary table drive device.
FIG. 4 is a schematic diagram showing a second conventional example, and FIG. 5 is a schematic diagram showing a third conventional example. 1...Rotary table, 4...Motor, 10...
... Base, 12 ... Rotation shaft, 14 ... Ball screw shaft, 15 ... Fixed support shaft, 16 ... Rotation guide,
17...Ball screw nut, 18...Nut mounting plate.

Claims (1)

[Scope of utility model registration request] A ball screw shaft is directly connected to the rotating shaft of the motor fixedly attached to the base, or the ball screw shaft is formed by the rotating shaft itself, and the ball screw shaft is directly connected to the rotating shaft of the motor that is fixedly attached to the base, and the ball screw shaft is connected in the direction of the rotation center axis of the rotary table rotatably supported on the base. The ball screw shaft is disposed in a vertical plane, and a ball screw nut screwed onto the ball screw shaft is attached and fixed to the outer periphery of the rotary table. A micro-rotary table drive device characterized by the ability to follow the movement by deflection due to the elasticity of the shaft.