JPH03260416A - Gas bearing - Google Patents

Abstract

PURPOSE:To prevent dust in supplied gas from entering the clearance of a bearing by putting and fixing a throttle ring, consisting of an air-permeable porous material, on a bearing metal, and connecting gas supply passage to circular space which is formed on the outside of the throttle ring. CONSTITUTION:As for a radial gas bearing 13, a throttle ring 17 is put and fixed on an intermediate bearing metal 16 whose flange 16a protrudes on the outer periphery of the cylindrical inner end section. The ring 17 consists of moldings made of multiporous material which breathe such as ceramic. The inside diameter of the ring and the inside diameter of bearing metal 15 and 16 are constituted equally. A bearing clearance 18 is formed between these circumferential faces and outer peripheral face other than a large diameter section 12 of a shaft 11. The outside diameter of the ring 17 is formed smaller than the outside diameter of bearing metal 15 and 16. Circular space 20 which is surrounded by the outer peripheral face of the ring 17, the outer peripheral face at opposing ends of bearing metal 15 and 16, and inner peripheral face of a support metal 19 is connected to a gas supply passage 21 which is formed in the support metal 19.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to improvements in gas bearings.

[Prior Art] Conventionally, gas bearings include slot air supply bearings and point air supply bearings. As shown in FIG. 4, the slotted air supply bearing has a slot gap 3 formed between the inner peripheries of the bearing metal 1.2, and pressurized air is supplied to the annular space 4 formed on the outer periphery of this gap 3. The gas is blown out from the inner periphery of this gap 3 by using the continuous slot gap in the circumferential direction as a diaphragm.
A thin shim 5 is sandwiched between them. In addition, as shown in FIG. 5, the point air supply bearing has a large number of air supply holes 7 that pass through the bearing metal 6 in the radial direction and are formed at equal intervals in the circumferential direction.
Pressure gas is supplied from an annular space 9 formed between the support plate (not shown) provided on the outer circumferential side of the air supply hole 7, and the pressure gas is blown out from the inner end of the air supply hole 7. In addition, Figures 4 and 5
In the figure, 8 indicates a shaft to be supported.

In the slot air supply bearing, gas flows along the axial direction of the shaft 8 from the slot gap 3 that is continuous in the circumferential direction. It has excellent rigidity and load capacity.

[Problem to be solved by the invention]

Conventional slotted air supply bearings have a slot gap of several lOμ
Since it is difficult to manufacture thin shims, it is difficult to accurately control the slot and 7-tooth clearances, making it difficult to obtain the specified bearing rigidity. Ta.

This invention solves the above-mentioned problems of the slot air supply bearing, and provides a gas bearing that has almost the same bearing performance as the slot air supply bearing, can be easily produced, and further prevents dirt from entering the bearing gap. The purpose is to

[Means for Solving the Problems] The gas bearing according to the present invention has a drawing ring made of a porous material that is air permeable sandwiched between bearing metals, and a gas supply path is formed in an annular space formed outside the ring. It is connected.

C Effect] In the gas bearing according to the present invention, the pressurized gas supplied from the gas supply path passes through the annular space and is squeezed by the aperture ring made of a porous material made of ceramic or the like and has air permeability. It flows out from the bearing surface of the surface and inner end surface. Since the aperture ring is made of a porous material, the gas flows out almost evenly in the circumferential and axial directions of the inner circumferential surface, and the bearing performance is almost the same as that of conventional slotted air supply bearings. can get. Further, the aperture ring is made of a porous material such as ceramic, and the bearing performance can be easily changed by adjusting the height, thickness, ring diameter, or porosity. Furthermore, since the aperture ring is made of a porous material, it can act as a filter, trapping dust in the supplied gas and preventing it from entering the bearing gap.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1.

In FIG. 1, 11 is a shaft having a large diameter portion 12 in the middle, and left and right radial gas bearings 13 and left and right thrust gas bearings 14 are provided at both ends of the shaft 11 and on both sides of the large diameter portion 12. They are arranged symmetrically, one on the left and one on the right.

In the radial gas bearing 13, an aperture ring 17 is clamped and fixed between the inner end of a cylindrical end bearing 15 and an intermediate bearing 16 having a flange 16a protruding from the outer periphery of the inner end of the cylindrical portion. has been done. The aperture ring 17 is made of a molded product made of an air-permeable porous material such as ceramic, and the inner diameter of the aperture ring 17 is equal to the inner diameters of the end bearing metal 15 and the intermediate bearing metal 16, and A bearing gap 18 is formed between the shaft 11 and the outer peripheral surface of the shaft 11 other than the large diameter portion 12. Further, the aperture ring 17 has an outer circumferential portion 17b protruding from both ends of the inner circumferential portion 17a via steps 17c, and an outer circumferential portion 17b protruding from both ends of the inner circumferential portion 17a.
The axial length of the outer peripheral portion 17b is longer than that of the outer circumferential portion 17b. The opposing surfaces of the end bearing metal 15 and the intermediate bearing metal 16 are formed in a shape that closely contacts the end face of the aperture ring 17, and the outer peripheral surfaces of the cylindrical portions of the end bearing metal 15 and the intermediate bearing metal 16 are formed into supporting metal parts. 19 is fitted and fixed. Furthermore, the outer diameter of the aperture ring 17 is formed smaller than the outer diameter of the end bearing metal 15 and the intermediate bearing metal 16, and the outer circumferential surface of the aperture ring 17 and the outer peripheral part of the opposing end surfaces of the end bearing metal 15 and the intermediate bearing metal 16 An annular space 20 surrounded by the support metal 19 and the inner peripheral surface of the support metal 19 is
It is connected to a gas supply path 21 formed inside.

In the thrust gas bearing 14, a throttle ring 23 is clamped and fixed between the outer peripheral surface of the flange 16a of the intermediate bearing metal 16 and the inner peripheral surface of the outer peripheral bearing metal 22. The aperture ring 23 is made of a molded article of an air-permeable porous material such as ceramic, similar to the aperture ring 17 of the radial gas bearing 13.
Aperture ring 23, intermediate bearing metal 16, and outer peripheral bearing metal 2
The inner end surfaces of the shaft 11 are located on the same plane, and a bearing gap 24 is formed between these inner end surfaces and the end surface of the large diameter portion 12 of the shaft 11. In addition, the aperture ring 23 has an outer end 23b protruding from the outer peripheral surface of the inner end 23a via a step 23c.
The outer end 23b is longer in radial length than the inner end 23a. The opposing peripheral surfaces of the flange 16a of the intermediate bearing metal 16 and the outer peripheral bearing metal 22 are formed in a shape that closely contacts the circumferential surface of the draw ring 23, and the outer end surfaces of the flange 16a and the outer peripheral bearing metal 22 form the support metal 19. It is supported and fixed to an end surface 19b of a large inner diameter portion 19a formed in the inner diameter portion 19a.

Furthermore, the axial length of the aperture ring 23 is longer than the flange 16a.
and is formed shorter than the axial length of the outer circumferential bearing metal 22, and is surrounded by the outer end surface of the drawing ring 23, the outer end of the opposing peripheral surface of the flange 16a and the outer peripheral bearing metal 22, and the end surface 19b of the support metal 19. An annular space 25 is connected to a gas supply path 21 formed in the support metal 19 .

Note that the support metal 19 is divided as appropriate so that each bearing metal 15, 16, 22 and aperture ring 17.23 can be held and fixed, and the space 19 in the large inner diameter portion 19a of the support metal 19 is divided into parts.
c is communicated with the atmosphere via a gas discharge path (not shown). Further, the gas supply path 21 is connected to a supply source (not shown) of pressurized gas such as compressed air.

In the static pressure gas bearing of the embodiment configured as described above, pressure gas is supplied from the supply source to the gas supply path 21 and the annular space 2.
By supplying the pressure gas to the throttle ring 17 of the radial gas bearing 13 through 0, the supplied pressure gas is throttled by the throttle ring 17 and flows out from the inner peripheral surfaces of these to the bearing gap 18, and the bearing 1
1 in the radial direction. In addition, by supplying pressurized gas from the supply source to the throttle ring 23 of the thrust gas bearing 14 through the gas supply path 21 and the annular space 25, the supplied pressure gas is throttled by the throttle ring 23 and flows from the inner end surface of the bearing to the thrust gas bearing 14. It flows into the gap 24 and supports the large diameter portion 12 of the shaft 11 in the thrust direction. Therefore 1, radial bearing 1
3] In the case of 7, the bearing height (radial length) h2. Adjust the thickness (axial length of the inner circumference) t and diameter (inner diameter length) φd, and in the case of the aperture ring 23 of the bearing 14, as shown in FIG. Height (axial thickness) hz, thickness (
radial length of inner end) t2. Diameter (length of inner end center diameter) φd2. By adjusting , the flow rate of pressure gas can be changed. Also, the material of the porous material constituting the aperture ring 17.23.

The flow rate of the pressure gas can also be changed by adjusting the particle size and the like.

Although the above embodiments have been described as having both a radial bearing and a thrust bearing, the present invention may be applied to only one of the radial bearing and the thrust bearing. Also,
The aperture ring is not limited to ceramic, and may be made of an air permeable porous material made of an appropriate material such as sintered metal powder.

[Effects of the Invention] As explained above, the gas bearing of the present invention has an aperture ring made of an air-permeable porous material sandwiched between the bearing metals, and gas is supplied to the annular space formed outside the ring. By connecting the channels, the following effects can be obtained.

That is, in the gas bearing of the present invention, the pressurized gas supplied from the gas supply path passes through the annular space and is squeezed by the aperture ring made of a porous material made of ceramic, ink, etc., and is made of an air-permeable porous material. It flows out from the bearing surface of the surface and inner end surface. Since the aperture ring is made of a porous material, the gas flows out almost evenly in the circumferential and axial directions of the inner circumferential surface, and the bearing performance is almost the same as that of conventional slotted air supply bearings. can get. In addition, the aperture ring is made of a porous material such as ceramic, and the bearing performance can be easily changed by adjusting the height, thickness, ring diameter, or porosity. Therefore, it is easy to manufacture. Out. Furthermore, since the aperture ring is made of a porous material, it has the effect of acting as a filter and trapping dust in the supplied gas to prevent it from entering the bearing gap.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a gas bearing according to an embodiment of the present invention, FIGS. 2 and 3 are sectional explanatory views of radial and thrust aperture rings, and FIGS. 4 and 5 are different from each other. FIG. 2 is a vertical cross-sectional view of main parts of a conventional gas bearing. DESCRIPTION OF SYMBOLS 11... Shaft, 12... Large diameter part, 13... Radial bearing, 14... Thrust bearing, 15... End bearing metal, 16... Intermediate bearing metal, 16a... Flange ,■7
... Aperture ring, 18 ... Bearing gap, 19 ... Support metal, 20 ... Annular space, 21 ... Gas supply path, 2
2...Outer peripheral bearing metal, 23...Aperture ring, 24.
...Bearing clearance, 25...Annular space. Sai/ Zuzai Zugazuzu"t, 2

Claims (1)

[Claims] 1. A gas bearing characterized in that an aperture ring made of an air-permeable porous material is sandwiched between bearing metals, and a gas supply path is connected to an annular space formed outside the ring.