JPS632661Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a sectional view of a thrust bearing commonly used in conventional rotating machines. In the figure, a sliding bearing 03 is attached to a casing 04 facing a thrust collar 02 provided on a rotor 01. Further, lubricating oil for lubricating the slide bearing 03 is supplied from the outside through the oil supply hole 05, for example.

Suppose now that a thrust load F is applied to the rotor 01 in the direction of the arrow, the rotor 01 moves in the same direction as the direction in which the thrust load is applied to generate an oil film pressure commensurate with the pressure, and the sliding bearing 03
A narrow gap h is formed between the two. Thrust load F
The relationship between and the clearance h is shown in Figure 2. When the thrust load is large, this clearance becomes extremely narrow, and eventually the sliding bearing 03 and the thrust collar 02
If they come into direct contact with each other, there is a risk of fatal injury.

Therefore, when the thrust load is large, it is necessary to increase the size of the slide bearing 03, and the outer diameter has to be increased. Furthermore, as the outer diameter increases, the circumferential speed increases, resulting in increased friction loss and a high temperature rise.

Therefore, by focusing on the case where the thrust load is large, having a large sliding bearing 03 even when the thrust load is small will increase the friction loss and temperature rise, and the former will reduce the efficiency of the rotating machine. However, the latter was not preferable because it caused a decrease in the strength of the bearing material and deterioration of the lubricating oil.

Therefore, the present inventor conducted intensive research to improve the above-mentioned drawbacks of the conventional technology, and found that by combining a sliding bearing and a magnetic bearing that utilizes the repulsive force of a magnet, the inventor of the present invention found that when the thrust load is small, the magnetic bearing alone can handle the load. The present invention was developed based on the discovery that it is possible to obtain a thrust bearing in which the sliding bearing also shares the load when the thrust load increases.

That is, the present invention provides a magnetic bearing that is fixed to a rotating shaft and is formed of a magnetic material, and the opposing portion is made of a magnetic material and has the same polarity as the opposing portion of the magnetic material, on the pressure-receiving surface of the housing that faces the thrust collar that is partially made of a magnetic material. It is an object of the present invention to provide a thrust bearing in which a slide bearing is disposed, and the back surface of the magnetic bearing is supported by the housing via an elastic member.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 3 and 4 show embodiments of the present invention,
FIG. 3 shows the operating state when the thrust load is small, and FIG. 4 shows the operating state when the thrust load is large.

In the figure, a thrust collar 2 provided on a rotor 1 has a portion on the inner diameter side made of a magnetic material 6. On the other hand, in the housing 4 facing this, a sliding bearing 3 is located on the outer diameter side, and a magnetic body 7 constituting a magnetic bearing is located on the inner diameter side. 8, and a convex stopper 9 is provided on the housing side. In addition, the opposing surfaces of both magnetic bodies 6 and 7 are of the same polarity (that is, N-pole or S-pole), and lubricant is supplied to the sliding bearing 3 from an oil supply hole, etc. (not shown). It's getting old.

Now, when the thrust load F is small, the magnetic body 7 is located closer to the thrust collar 2 than the sliding bearing 3 due to the elastic body 8 (that is, gap h ₁ < gap h ₂ ), and the thrust load F is 7 alone, and the friction loss due to the sliding bearing 3 is small because the gap _h2 is large, and the friction loss due to the magnetic body 7 is extremely small because there is no lubricant in the gap _h1 .

As the thrust load F increases, the magnetic body 7
As the elastic body 8 supporting the shrinks and the difference between the gap h ₂ and the gap h ₁ becomes smaller, the sliding bearing 3 also begins to share the load. Finally, the back surface of the magnetic body 7 comes into contact with the stopper 9, and the magnetic body 7 and the surface facing the thrust collar 2 of the sliding bearing 3 are on the same plane (i.e., gap h ₁ = gap h ₂ ), and both Even the bearings will bear a large thrust load F.

In this way, by changing the load sharing between the magnetic bearing and the plain bearing depending on the magnitude of the thrust load, when the thrust load is large, both bearings share the load, but when the thrust load is small, the magnetic bearing Since the load is carried only by the bearing, unnecessary friction loss and resulting temperature rise can be prevented.

In addition, in FIG. 3, the magnetic body 7 is placed inside the sliding bearing 3.
Although the case where the magnetic bearings are arranged in parallel on the outside is shown, other embodiments include arranging the magnetic bearings on the outside and the sliding bearings 3 on the inside in parallel as shown in FIG. They can also be arranged in series in the axial direction.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of a conventional thrust bearing, Fig. 2 is a diagram showing the relationship between thrust load and clearance in the case of Fig. 1, and Figs. 3 and 4 respectively show the operating state. FIGS. 5 and 6 are cross-sectional views of thrust bearings showing other embodiments of the present invention, respectively. FIGS. Explanation of the main parts of the diagram, 1... Rotor (rotating shaft),
2... Thrust collar, 3... Sliding bearing, 4...
...Housing, 6, 7...Magnetic body, 8...Elastic body (elastic member).

Claims (1)

[Scope of utility model registration request] A magnetic bearing made of a magnetic material whose opposing part has the same polarity as the opposing part of the magnetic material, and a sliding bearing are provided on the pressure receiving surface of the housing facing the thrust collar fixed to the rotating shaft and partially made of a magnetic material. What is claimed is: 1. A thrust bearing characterized in that the magnetic bearing has a rear surface supported by the housing via an elastic member.