JPS6263217A - Static gas bearing - Google Patents

Abstract

PURPOSE:To enhance the load bearing capacity of a bearing by providing a gas reservoir with an exhaust port at a point between a gas bearing inlet port and a magnetic fluid seal so as to increase the inlet air pressure without contaminating the ambient environment. CONSTITUTION:A ring-shaped permanent magnet 3, which is placed between two pole-pieces 4 and 4 made up of ring-shaped magnetic plates, is installed at both ends of a frame 2 with a static gas bearing 10. This permanent magnet 3 is magnetized in the axial direction with magnetic poles N and S. Magnetic fluid 5 is sealed in between the external part of a shaft 1, which is made of a magnetic material and which can rotate, and the internal part of the pole pieces 4, thereby forming a magnetic fluid seal. A gas reservoir 8, from which an exhaust port is formed toward the outside, is provided in between an inlet port 6 of the static gas bearing 10 and the magnetic fluid seal 5. By making the total sectional area of the exhaust port 7 greater than the clearance- sectional-area between the bearing 10 and the shaft 1, the gas pressure acting on the magnetic fluid 5 can be lowered. As a result, the gas leak in the axial direction can be prevented and the inlet air pressure can be heightened, thereby increasing the load bearing capacity of the bearing.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a hydrostatic gas bearing.

[Prior art and problems]

A side sectional view of a conventional example of this type of bearing is shown in FIG.

In the hydrostatic gas bearing 10, the bearing exhaust is connected to the shaft 1 and the bearing 10.
Since the gas is released into the surrounding environment outside the bearing through the gap between the bearing 10 and the bearing 10, if the surrounding environment is vacuum or different from the gas used in the bearing 10, there is a drawback that the gas used in the bearing 10 may cause contamination.

Note that 6 is an air supply hole through which gas is introduced.

Another conventional example that improves the above-mentioned drawbacks is a hydrostatic gas bearing in which gas is sealed with a magnetic fluid seal, which is shown in a side sectional view in FIG.

With respect to the fixed part 11, the rotating body 12 has an axis (rotating axis 1
), the rotating body 12 rotates as shown by the arrow, and magnetic fluids 5 are provided at both ends of the surface facing the fixed part 11 of the rotating body 12, and these magnetic fluids 5 do not form part of the magnetic path formed by the permanent magnets 3. Filled gas 9 is sealed inside the rotating body 12 which is in contact with the fixed part 11 and surrounded by the magnetic fluid 5 -C
There is.

In this conventional example, a total pressure of 1.1 million sq.9 is applied to the magnetic fluid seal 5, so the magnetic fluid seal 5 has a low pressure resistance and a low bearing load capacity.

In order to increase the bearing load capacity, there is a method in which the magnetic fluid seal 5 is multi-staged, but a new drawback arises in that the shape becomes large.

Another prior art example of a bearing that greatly increases bearing load capacity is the bearing shown in side cross-sectional view in FIG.

That is, an air supply port 6 connected to an air supply source 13 is formed at approximately medium heat on the bearing surface 10a, permanent magnets 3 are fixed to both ends of the bearing surface 10a, and magnetic fine powder is placed on these permanent magnets 3. This is a hydrostatic air bearing 10 that attracts and supports a magnetic fluid film 5 made of oil having lubricating properties.

This changes the restriction of the gas discharged to the outside of the lJ1 bearing, improves the bearing bearing capacity, and also increases the magnetic fluid 5
The oil film formed by the bearing surface 10a and the support member 12
However, in this case, the principle is the same as that shown in FIG. 3, and a large bearing load capacity cannot be obtained.

Furthermore, the drawback that the surrounding environment is contaminated by the exhaust air from the bearing 10 and the magnetic fluid 5 cannot be improved.

[Object of the Invention] The present invention overcomes the drawbacks of the conventional examples and prevents gas from leaking in the axial direction from the gap between the shaft and the bearing, thereby preventing polluting the surrounding environment and providing a bearing with a high bearing load capacity. Its purpose is to provide.

[Summary of the invention]

In order to achieve the object of the present invention (1), the exhaust hole of the gas bearing is provided between the bearing air supply hole and the magnetic fluid seal. This is a clean static pressure gas bearing that prevents gas from leaking in any direction and does not pollute the surrounding area.

〔Example〕

FIG. 1 shows a side view of an embodiment of the present invention taken in section 1J.

In all drawings, the same reference numeral 8 indicates the same or corresponding parts.

A ring-shaped permanent magnet 3 sandwiched between 402 ring-shaped pole pieces made of magnetic flat plates is installed at both ends of the frame 20 on which the hydrostatic gas bearing 10 is located.

This permanent magnet has magnetic poles N and S magnetized in the axial direction.

Then, a magnetic fluid 5 is sealed between the outer circumference of the rotating shaft 1 made of a magnetic material and the inner circumference of the pole piece 4 to provide a magnetic fluid seal.

In addition, the air supply hole 6 of the static pressure gas bearing 10 and the magnetic fluid seal 5
In between, a gas reservoir 8 is provided, and an exhaust hole 7 is bored in the gas reservoir 8.

The present invention is configured in this manner.

Note that the gas flow path, that is, the air supply hole 6. The arrows in the gas reservoir 8 and exhaust hole 7 represent the gas flow path and its direction.

By making the total cross-sectional area of the exhaust hole 7 larger than the cross-sectional area of the gap between the bearing 10 and the shaft 1, and reducing the gas pressure applied to the magnetic fluid 5 injected between the pole piece 4 and the shaft 1, the magnetic fluid The pressure resistance of the seal 5 prevents gas leakage in the axial direction.

〔Effect of the invention〕

Thus, according to the present invention, (1) a high supply pressure can be obtained, so a high bearing load capacity can be obtained; (2) the number of stages of magnetic fluid seals can be reduced, so it can be made compact.

I'm shy, curious about the field, and very knowledgeable.

[Brief explanation of drawings]

Figure 1 (31 Side sectional view of one embodiment of the present invention, Figure 2 41
FIG. 4 is an explanatory diagram of an example of 1.1 dependent flux. 1...Axis, 2...Frame, 3...A<Kuma magnet,
4... Pole piece, 5... Magnetic fluid, 6... Air supply hole, 7... fJl air hole, 8... Gas reservoir, 9...
Jl=1 person gas, 10...bearing, 10a...bearing surface, 11...fixed part, 12...rotating body. Support staff, 13...Air supply source. Applicant's agent Fujio Fuji Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. In a bearing in which magnetic fluid seals are provided at both ends of the hydrostatic gas bearing, a gas reservoir is provided between the gas bearing air supply hole and the magnetic fluid seal, and an exhaust hole is provided in this gas reservoir. , a hydrostatic gas bearing characterized by: