JPS626336Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a static pressure gas bearing device used for the main shaft of a machine tool, etc. Specifically, the invention is a device that concentrates exhaust gas from the bearing and prevents foreign matter from entering inside the bearing. This invention relates to a static pressure gas bearing device.

In conventional hydrostatic gas bearing devices, dust prevention between a rotating body such as a shaft and a rotated body such as a sleeve has generally been achieved by exhausting air from a bearing portion adjacent to the space. In other words, what is shown in Figure 1 is axis 1.
a, an example of a conventional hydrostatic gas bearing device consisting of a sleeve 10a; The shaft 1a has its outer peripheral surface serving as a radial bearing surface 2a, and its side surface serving as a thrust bearing surface 3a.
The sleeve 10a has a radial bearing surface 20a and a thrust bearing surface 30a that face the radial bearing surface 2a and the thrust bearing surface 3a, and the sleeve 10a has a radial bearing surface 20a and a thrust bearing surface 30a that are opposite to the radial bearing surface 2a and the thrust bearing surface 3a, and the sleeve 10a has a radial bearing surface 20a and a thrust bearing surface 30a. , 30a, and have supply holes 40a, 50a for introducing pressure gas between them, forming a radial bearing section and a thrust bearing section. and,
The sleeve 10a is provided with a discharge hole 60a that communicates with the outer periphery of the sleeve 10a from both ends of the radial bearing section and discharges pressure gas from the radial bearing section side of the radial bearing section and the thrust bearing section to the outside air.

Therefore, in this conventional hydrostatic gas bearing device, the pressure gas is dispersed and exhausted in the directions of arrows A and B, and the shaft 1
Dust prevention between the outer periphery of the sleeve 10a and the inner periphery of the sleeve 10a is achieved by partially exhausting air A from the thrust bearing section adjacent to the space. Therefore, in the conventional type, the gas flow to prevent foreign matter from entering was weak, and dustproofing was not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydrostatic gas bearing that solves the above-mentioned conventional drawbacks.

The present invention solves the above drawbacks by merging the exhaust gas from the thrust bearing section and the radial bearing section and discharging it between the rotating body and the rotated body.

Next, the present invention will be explained according to the embodiment shown in FIG. The hydrostatic gas bearing device of this embodiment consists of a shaft 1, which is the main shaft of a machine tool, and a sleeve 2. The shaft 1 is provided with a collar 11 on the work side, the outer circumferential surface of which serves as a radial receiving surface 111, and the side surface thereof serving as a thrust receiving surface 112. Sleeve 2 has tsuba 11
The sleeve body 21 is shaped like a cylinder and wraps around the radial bearing surface 111 of the sleeve body 21 with a slight gap, and the thrust bearing surface 11 is fixed to both sides of the sleeve body 21.
2 and a plate-shaped thrust receiving member 22 arranged so as to provide a slight gap between the thrust receiving member 22 and the thrust receiving member 22. The inner peripheral surface of the sleeve body 21 is the radial receiving surface 1
11 is a radial bearing surface 212, and the inner surface of the thrust bearing member 22 is the thrust bearing surface 112.
The thrust bearing surface 222 is opposed to the thrust bearing surface 222 . An appropriate number of pressurized gas supply holes 211 are provided in the axial center of the sleeve body 21 in the circumferential direction. An appropriate number of pressurized gas supply holes 221 are provided in the thrust receiving member 22 in the circumferential direction, corresponding to substantially the center of the effective length of the thrust receiving surface 112 in the radial direction. These supply holes 211, 221
is connected to a pressure gas supply source (not shown).
In this way, pressure gas is introduced from the supply hole 211 between the radial bearing surface 111 and the radial bearing surface 212 to form the radial bearing part, and pressure gas is introduced from the supply hole 221 between the thrust bearing surface 112 and the thrust bearing surface 222. is guided to form the thrust bearing section. The thrust bearing member 22 of the sleeve 2 has a radial bearing surface 212 and a thrust bearing surface 22.
An appropriate number of discharge holes 224 are provided in the circumferential direction to communicate with the inner circumferential surface 223 of the thrust receiving member 22 facing the outer circumferential surface 12 of the shaft 1 from the vicinity of the intersection of the two. Therefore, the exhaust from the radial bearing and the exhaust from the radial bearing of the thrust bearing merge through the exhaust hole 224 and concentrate between the outer circumferential surface 12 of the shaft 1 and the inner circumferential surface 223 of the sleeve 2. In other words, the air is discharged as indicated by arrow A, and the space between the shaft 1, which is a rotating body, and the sleeve 2, which is a rotated body, is dust-proofed. Furthermore, the exhaust on the side opposite to the radial bearing of the thrust bearing is also
The exhaust is shown by arrow A between the outer circumferential surface 12 of the sleeve 2 and the inner circumferential surface 223 of the sleeve 2. In addition, in this embodiment, a radial bearing portion is formed by guiding pressure gas from the supply hole 31 provided in the sleeve 3 to the outer peripheral surface 12 of the shaft 1 on the side opposite to the workpiece, thereby increasing the rigidity and stability of the bearing device. .

As explained above, in this invention, the exhaust gas from the radial bearing section and the exhaust gas from the thrust bearing section are combined and discharged centrally through the exhaust hole provided in the sleeve on the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve. , the dustproof performance between the rotating body and the rotated body is significantly improved compared to the conventional type.

In the embodiments, the static pressure gas bearing is of orifice type, but any type of static pressure gas bearing, such as a self-drawn type or a porous type, can be used.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the conventional technique, and FIG. 2 is a vertical cross-sectional view of an embodiment of the present invention.
is the discharge hole.

Claims (1)

[Claims for Utility Model Registration] (1) A shaft having a flange whose outer peripheral surface is a radial bearing surface and whose side surface is a thrust bearing surface, and a sleeve having a radial bearing surface and a thrust bearing surface facing each of the bearing surfaces. In a static pressure gas bearing device, in which pressurized gas is introduced from the outside between the respective bearing surfaces and the respective bearing surfaces, the pressurized gas is discharged to the sleeve between the outer circumferential surface of the shaft and the inner circumferential surface of the sleeve. A static pressure gas bearing device characterized in that a discharge hole is provided between the spaces. (2) The hydrostatic gas bearing device according to claim 1, wherein the discharge hole communicates with the inner circumferential surface of the sleeve from near the intersection of the radial bearing surface and the thrust bearing surface.