JPH0622780B2 - Machine Tools - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool, and more particularly to a machine tool suitable for performing highly accurate machining.

[Background of the Invention]

In order to improve the machining accuracy of a machine tool, it is necessary to improve the accuracy of the machine tool itself. However, increasing the accuracy of the machine tool itself is limited from a technical or economic point of view. Therefore, for example, Japanese Patent Laid-Open No. 54-10
As disclosed in Japanese Patent No. 2671, there has been proposed one in which a correction means for correcting the accuracy of a machine tool is provided to improve the processing accuracy.

According to such a machine tool, since the machining is performed according to the precision of the reference block regardless of the precision of the machine tool itself, highly precise machining can be performed. However, since the straightness of the reference block in the direction parallel to the reference plane cannot be corrected, it is not possible to prevent the processing accuracy from deteriorating due to the inclination or vertical movement of the moving body.

[Object of the Invention]

An object of the present invention is to provide a machine tool capable of highly accurately correcting the straightness of a moving path of a moving body and obtaining high processing accuracy.

[Outline of Invention]

In order to achieve the above object, in the present invention, the moving body is provided with a sliding member in contact with the guide surface of the fixed member and a minute displacement means, and the output of the straightness detecting means for detecting the straightness of the moving path of the moving body. Based on the above, the minute displacement means is operated to correct the straightness of the moving path of the moving body with high accuracy.

Example of Invention

 An embodiment of the present invention will be described below with reference to the drawings.

1 to 6 show an embodiment of the present invention. In FIG. 1, a saddle 2 is fixed on a bed 1, and a table base 3 is movable along a guide surface (not shown) formed on the saddle 2 in a direction perpendicular to the paper surface.
Is supported. A table 4 for supporting and fixing a workpiece (not shown) is fixed on the table base 3. A minute displacement means 7 is fixed to a bearing 6 slidably in contact with a guide surface 5 formed on the upper surface of the bed 1, and a column 8 is fixed to the minute displacement means 7. In this column 8, the spindle head 9 is
It is slidably supported in the vertical direction along a guide surface (not shown) formed on the. A blade 11 is supported at one end of a spindle 10 rotatably supported by the spindle head 9. A light projecting means 13 is supported on the bed 1 via a bracket 12. On the other hand, in the lower part of the column 8, the light position detecting means 1 facing the light projecting means 13 is provided.
4 is fixed.

The light projecting means 13 projects a pair of parallel straight reference light beams (hereinafter, simply referred to as light beams) 15 and 16 along a path along which the column 8 should move, and is composed of, for example, a laser oscillator. It

The light position detecting means 14 includes a pair of light receiving elements 17 and 18 arranged so as to intersect the optical paths of the light rays 15 and 16 oscillated from the light projecting means 13. For these light receiving elements 17 and 18, for example, an optical position detecting element 20 as shown in FIG. 2 is used. This optical position detection element 20
Is generated by receiving the light ray 15 (or 16), X ₁ , X
₂ is taken out from the electrodes 21 and 22, and the light receiving position is known by the size of each. That is, the currents X ₁ and X ₂ generated at the light receiving position are
Since the light is output through the resistance layer at a distance of up to 22, the light receiving position is obtained by comparing the sizes, and a displacement of several μm can be detected. In order to detect a further minute displacement by the optical position detecting element 20, as shown in FIG. 3, the displacement amount Δy is set by inclining the optical axis of the light ray 15 by an angle θ.
Should be expanded to the displacement amount ΔS. At this time, the amount of ΔS with respect to Δy is Can be found at. For example, when θ is set to 5 degrees, a displacement amount of 1 μm or less can be detected.

The position detection using the optical position detection element 20 is performed by a detection circuit 23 as shown in FIG. This detection circuit 2
3 is addition (X ₁ + X ₂ ) and subtraction (X ₁ ) of the currents X ₁ and X ₂ applied from the electrodes 21 and 22 of the optical position detection element 20.
-X ₂ ) thickening devices 24 and 25 and thickening devices 24, 2
Filter 2 for removing noise included in the signal from 5
6 and 27 and the signals applied from the filters 26 and 27 to provide a divider 28 for obtaining the light receiving position on the optical position detecting element 20.

As shown in FIG. 1, the straightness detecting means includes a light projecting means 13, a pair of light position detecting elements 20 arranged at a predetermined interval in the light position detecting means 14, and each light position detecting element 20. And a pair of detection circuits 23 (see FIG. 4) connected to each other.

The straightness of the column 8 is detected by the straightness detecting means as described below.

First, when the column 8 is at the reference position (for example, the right end of the base 1), the light receiving position of the light position detecting element 20 is detected and stored. Then, the column 8 is moved to detect the change in the light receiving position of the light position detecting element 20. And
Compared with the detection result at the reference position, the difference Δy1, Δy2
Ask for.

As shown in FIG. 5, the minute displacement means 7 is a movable wedge 32 slidably fitted in a guide groove 31 formed in the bearing 6, and is fixed to the bearing 6 to move the movable wedge 32. And a feed screw 34 having one end coupled to the motor 33 and the other end screwed into a screw hole (not shown) having the movable wedge 32 formed therein.
And the column 8 so as to come into contact with the movable wedge 32.
It consists of a fixed wedge 35 fixed to the. When the movable wedge 32 moves in the arrow direction, the column 8 is pushed up in the arrow direction.

The displacement of the column 8 is corrected by the minute displacement means 7 as follows.

The detection circuit 23 detects the light receiving position of the optical position detecting element 20 based on the signal from the optical position detecting element 20. The arithmetic circuit 40 receiving the output of the detection circuit 23
The signal of the light receiving position of the optical position detecting element 20 at the previously stored reference position is compared with the newly applied signal, the displacement amount is obtained, and the direction and the movement of the movable wedge 32 are to be moved. The amount is calculated and the control circuit 41
Apply to. The control circuit 41 rotates the motor 33 and moves the movable wedge 32 based on a command from the arithmetic circuit 40. Then, the fixed wedge 35 moves in the vertical direction by the relative movement of the movable wedge 32 and the fixed wedge 35, and the column 8 moves up and down.

In this way, according to the output of the optical position detection element 20,
By moving the movable wedge 32 corresponding to the light position detecting element 20, the vertical movement or inclination of the column 8 can be corrected.

In addition, the column 8 may be reciprocated several times to obtain the straightness of the movement path of the column 8 and the average value at each point may be obtained and corrected. A piezoelectric element may be used to change the applied voltage according to the amount of displacement of the column 8.

In the above embodiment, the column 8 moving on the bed 1
Although the detection and correction of the straightness in the specific direction has been described, the straightness of the column 8 can be corrected with high accuracy by appropriately disposing the detecting means and the minute displacement means. Further, the straightness of the moving path of the spindle head 9 with respect to the column 8 can be corrected by using the column 8 as a fixed member and the spindle head 9 as a moving body.

〔The invention's effect〕

As described above, according to the present invention, since the straightness of the moving path of the moving body of the machine tool can be maintained with high precision, there is an effect that high-precision machining can be performed.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a machine tool to which the present invention is applied, FIG. 2 is a side view of an optical position detecting element in FIG. 1, and FIG. 3 shows a detection principle by the optical position detecting element. A side view, FIG. 4 is a block diagram of a detection circuit for detecting the amount of displacement, FIG. 5 is a side view showing an example of the minute displacement means in FIG. 1, and FIG. 6 is a block line showing a correction circuit. It is a figure. 1 ... bed, 2 ... saddle, 3 ... table base,
4 ... Table, 5 ... Guide surface, 6 ... Bearing, 7
…… Small displacement means, 8 …… Column, 9 …… Spindle head, 13
...... Light emitting means, 14 ...... Light position detecting means.

Claims (1)

[Claims] 1. A machine tool comprising: a fixed member having a guide surface formed thereon; and a movable body supported by a plurality of sliding members slidably contacting the guide surface and moving along the guide surface. The movable body and the sliding member are movably coupled to each other in a direction perpendicular to the moving direction, and a minute displacement means is provided between the movable body and the sliding member, and the minute displacement means is arranged on the fixed member side. Of a reference light beam parallel to the path to be moved, and a light receiving element arranged on the moving body so as to intersect the reference light beam, and detect the position where the reference light beam is received. And a straightness detecting means for detecting the displacement amount of the moving body with respect to the reference ray from the output of the light position detecting means, and the minute displacement means is operated by the output of the straightness detecting means. Characterized by the fact that Machine.