JPH033708A - Spindle - Google Patents

Abstract

PURPOSE:To improve the accuracy of machining by constructing a spindle in a way that a flange is provided at a tool side relative to a static pressure bearing in a radial direction and a static pressure bearing in a thrust direction is arranged at this flange. CONSTITUTION:When a copper core 11 is driven by a motor coil 12 to rotate a rotor 10, the rotor 10 is inducted and heated by the copper core 11 to be expanded and extended in an axial direction. A flange 15 is provided at a tool 29 side relative to a static pressure bearing 13 in a radial direction, on the outer circumference of the rotor 10, and a static pressure bearing 16 in a thrust direction is provided at the flange 15. The rotor 10 therefore extends to the opposite side of the tool 29 starting from the position of the flange 15, a point of origin. Due to this, extension toward the tool 29 side is canceled, and the tool 29 side of the rotor 10 from the flange 15 being the point of origin is not subject to the influence of heating, temperature rise at this portion is very little so that the change of the length l from the flange 15 to the top end of the tool 29 gripped by a collet 22 is considered to be almost nothing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention (1) A static pressure bearing in the radial direction is arranged around the outer periphery of an integrally aligned rotor, and a flange provided on the outer periphery of the rotor is provided with a static pressure bearing in the thrust direction. This type of spindle is equipped with a hydrostatic bearing, and is mainly suitable for drilling holes.

[Prior technology] For hole drilling, a radial static pressure bearing is arranged around the outer periphery of an integrated rotor with alignment, and a thrust direction static pressure bearing is arranged on a flange provided on the outer periphery of the rotor. Spindles are widely used.

Conventionally, in this type of spindle, as shown in FIG. 2, a cylindrical rotor 4 is rotatably formed inside a spindle body 1, integrally with a centering 2, and holding a tool 3 at its tip. A motor coil 5 is wound around the alignment 2 of the rotor 4, and radial hydrostatic bearings 6 are arranged around the outer periphery of the rotor 4 on both sides of the alignment 2. Also, a flange 7 is provided on the outer periphery of the rotor 4 at a position opposite to the tool 3 with respect to the radial direction hydrostatic bearing 6, and a thrust direction hydrostatic pressure bearing 8 is disposed on this flange 7. The configuration is as follows.

[Problem III to be Solved by the Invention] The spindle of the above type expands and extends in the axial direction due to induction heating of the rotor 4 by the motor coil 5 in the alignment 2, and the elongation of the rotor 4 is 0 - evening. 4 and extends in the axial direction from a flange 7 fixed to the spindle body 1.

In the conventional spindle described above, since the flange 7 is located on the opposite side of the tool 3 with respect to the radial hydrostatic bearing 6, the rotor 4 extends in the direction of the tool 3, and as a result, the tool 3 The length up to the tip of the tube becomes longer by the length of the length.

As a result, when a conventional spindle is used to machine a blind hole with a defined depth, the hole becomes deeper by the length of the rotor 4, making it impossible to machine a blind hole with high precision.
Furthermore, when the workpiece to be blind-holed consists of a plurality of layers and the blind-hole is to be drilled up to a predetermined layer, there is a drawback that the tool 3 is too far to reach the next layer and may damage this layer.

The present invention provides a spindle which aims to eliminate the above-mentioned drawbacks.

[Means for Solving the Problems] In order to solve the above problems, the present invention arranges a radial static pressure bearing around the outer circumference of an integrally aligned rotor, and a flange provided on the outer circumference of the rotor. In a spindle of a type in which a static pressure bearing in the thrust direction is arranged, the flange is provided on the tool side with respect to the static pressure bearing in the radial direction, and a configuration is adopted in which the static pressure bearing in the thrust direction is arranged on this flange. .

[Function] Since the flange provided on the rotor is located on the tool side with respect to the radial direction static pressure bearing, and the thrust direction static pressure bearing is placed on this flange, the rotor is heated induced by alignment and expands. When the tool extends in the axial direction from the flange, this elongation extends to the opposite side of the tool from the flange, canceling out the elongation toward the tool. There is almost no temperature rise in this part, and there is almost no dimensional change from the flange to the tool light end.

[Examples] Hereinafter, the present invention will be described in detail based on examples shown in the drawings, but the present invention is not limited to the examples.

In Fig. 1, numeral 9 denotes a cylindrical spindle body, 10 denotes a rotor, 11 denotes an axially central portion f of the rotor 1o, which is integrally formed with the rotor 10, and 12 is wound around the aligner 11. 13 is a radial static pressure bearing placed around the front side (tool side) of the rotor 1o with respect to the alignment 11; 14 is a radial static pressure bearing placed around the rear side of the rotor 10; It is.

A flange 15 is provided on the outer periphery of the rotor 10 on the tool side with respect to the radial direction static pressure bearing 13, and a thrust direction static pressure bearing 16 is disposed on this flange 15. There is. 17. +8 is the radial hydrostatic bearing surface on the radial hydrostatic bearing 13°14, 1
9.20 is the thrust direction hydrostatic bearing surface on the radial direction hydrostatic pressure bearing 13 and the thrust direction hydrostatic pressure bearing 16, and 21 is the hydrostatic pressure bearing surface 17. This is an air passage that leads air to +8.19.20. From this air passage 21 to the hydrostatic bearing surface 17.18,
By supplying air to 19 and 20, the rotor 1o floats with a thin air film, and the rotor 1o is rotated by the alignment 11 driven by the motor coil 12.

A collet 22 is provided at the tip of the rotor 10 so as to be movable in the axial direction, and is configured to move toward the tip to open and retreat to close. 23 is a spring that urges the collet 22 in the backward direction; 24 is a bushing rod that presses the collet 22 in the distal direction against the elastic force of the spring 23 to open the collet 22; 25 is a diaphragm; 26 is a bushing rod return spring; 27. Reference numeral 28 denotes a diaphragm cover, which grasps the tool 29 by moving the collet 22 backward and closing due to the elastic force of the spring 23, and moves the diaphragm 25 by forcing air into the diaphragm covers 27 and 28. By pressing and moving the bushing rod 24, the collet 22 is pushed forward by the bushing rod 24, and the collet 22 is opened and the tool 29 can be removed.

Next, the present invention will be explained in detail.

When the motor coil 12 drives the alignment 11 and rotates the rotor 10, the rotor 1o is heated induced by the alignment 11 and expands and extends in the axial direction. A flange 15 is provided on the tool 29 side with respect to the bearing 13, and a static pressure bearing 16 in the thrust direction is disposed on this flange 15. It extends to the opposite side (in the direction of the upper arrow A in Figure 1), and the extension towards the tool 29 side (in the direction of the upper arrow in Figure 1) is canceled, and the tool 29 side with the flange 15 of the rotor 10 as the base point is The tool 29 gripped by the collet 22 from the flange 15 is hardly affected and the temperature rise in this part is extremely small.
The change in the dimensions up to the tip of the wire (within a few microns) can be treated as almost no change.

[Effects of the Invention] As described above, according to the present invention, a static pressure bearing in the radial direction is arranged around the outer periphery of an integrally aligned rotor, and static pressure in the thrust direction is applied to the flange provided on the outer periphery of the rotor. Arrange the bearing
In the aT type spindle, the flange is located on the tool side with respect to the radial hydrostatic bearing,
By arranging a static pressure bearing in the thrust direction on this flange, even if the rotor is aligned and elongated due to induced heating, the elongation toward the tool side is canceled, and the dimensional change up to the tip of the tool is small due to the wood, making it easier to process. The spindle can improve accuracy and is especially suitable for use in blind hole machining, which requires high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing an example of a conventional spindle. 1o...Rotor 11...Alignment 13.14...Radial Directional static pressure bearing 15... flange

Claims (1)

[Claims] In a spindle of a type in which a radial static pressure bearing is arranged around the outer periphery of an integrally aligned rotor, and a thrust direction static pressure bearing is arranged on a flange provided on the outer periphery of the rotor,
A spindle, wherein the flange is located on the tool side with respect to the radial hydrostatic bearing, and a thrust hydrostatic bearing is disposed on the flange.