JPS627852Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dynamic pressure air (gas) bearing, and more particularly to a multi-arc foil bearing that functions as a radial bearing.

Figure 1 shows a multi-arc bearing structure incorporated into the foil bearing, which has the characteristics of easily absorbing assembly errors and being suitable for high speeds, to enhance the vibration damping effect (the effect of increasing stability against self-excited vibrations of high-speed bearings). Multi-arc foil bearings have been proposed in the past. This multi-arc foil bearing has a single foil 2 provided with arcuate portions 2a, 2b, and 2c with a radius larger than the radius of the rotating shaft 1, and is supported by a support rod 3.
The arcuate portions 2a, 2b, and 2c of the foil 2 have elastic force such that they come into pressure contact with the outer periphery of the rotating shaft 1.
The smaller this elastic force is, the better in order to reduce the frictional resistance torque at the time of startup, but the larger the elastic force is, the better in terms of increasing the load capacity and vibration damping effect. However, the first
In the figure, the arcuate portions 2a, 2b of the foil 2,
Since the elastic force of 2c is approximately proportional to the amount of deflection thereof, it is not possible to reduce the frictional resistance torque at the time of startup and to increase the load capacity and vibration damping effect.

The object of the present invention is to make the elastic force of the foil rapidly increase as the deflection of the foil increases, thereby reducing the frictional resistance torque at startup and increasing the load capacity and vibration damping effect.

The configuration of the present invention to achieve this objective consists of interposing corrugated damping oil between the inner and outer circumferential parts of flat cylindrical topf oil, which is curved into an arc with a radius larger than the radius of the rotating shaft. A support in which a plurality of bearing pieces (or bearing pads) are arranged around a rotating shaft so that the inner periphery of the Topf oil contacts the rotating shaft, and each of these bearing pieces is inserted at both ends between the inner periphery and the outer periphery of the Topf oil. It is carried by a rod.

According to such a configuration, the elastic force that presses the inner circumference of the topfoil of each bearing piece against the outer circumferential surface of the rotating shaft is generated by the elasticity of the inner and outer circumferences of the topfoil and the damping oil, and the frictional resistance torque at the time of startup is generated. Even if the elastic force of the rotating shaft is set to a small value when the rotating shaft is stationary in order to reduce the As a result, tension is generated on the outer circumference of the Topf oil, and the outer circumference of the Topf oil is deformed and the dump oil is distorted. As a result, the elastic force that tries to press the inner circumference of the Topf oil against the outer circumferential surface of the rotating shaft rapidly increases. Large load capacity and vibration damping effect can be obtained.

Furthermore, since each bearing piece is made of Topf oil, high-frequency vibrations of the rotating shaft are applied to the Topf oil and dump oil, and an air film is formed between the Topf oil and the rotating shaft and between the Topf oil and the dump oil due to the squeeze film effect. This has the effect of further increasing the load capacity.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. This embodiment is an example in which a radial bearing of a rotating shaft 13 is provided with a turbine wheel 11 and a compressor wheel 12 at both ends in a turbocharger 10 for an automobile. The multi-arc oil bearing 14 is attached to the bearing housing 1 located between the turbine housing 15 and the compressor housing 16.
7 includes a spiral groove bearing (a type of hydrodynamic air bearing) 1 that functions as a thrust bearing for the rotating shaft 13.
It is arranged together with 8.

The multi-arc foil bearing 14 is attached to the bearing housing 1
No. 7, the hole 20 communicates with the atmosphere through the air hole 19.
It has three bearing pieces 21 arranged in a row around the rotating shaft 13 inside. Each bearing piece 21 includes a topfoil 22 made of phosphor bronze or spring steel with a thickness of approximately 60 μm, and an inner peripheral portion 22a of the topfoil 22.
and a dump oil 23, which is also made of phosphor bronze or spring steel and has a thickness of about 100 μm, and is interposed between the outer peripheral portion 22b. The top oil 22 has a flat cylindrical shape curved into an arc with a radius larger than the radius of the rotating shaft 13, and the dump oil 23 has a wave shape. Each bearing piece 21 has an annular shape supported on the inner circumference of the bearing housing 17. It is supported at both ends by two support rods 26 whose ends are supported by supports 24 and 25. Each support rod 26 is inserted between the inner peripheral part 22a and the outer peripheral part 22b of the top oil 22. When the rotating shaft 13 is at rest, the top oil inner peripheral portion 22a of each bearing piece 21 is in pressure contact with the outer periphery of the rotating shaft with the minimum necessary elastic force.

Thus, when the rotating shaft 13 is at rest, the pressure contact force between each bearing piece 21 and the rotating shaft 13 is the minimum necessary, so the frictional resistance torque when the rotating shaft 13 is started is small. Also, when the rotating shaft 13 rotates, the rotating shaft 13
Due to the rotation in the direction of the arrow, air is viscous and drawn into the three wedge spaces 27, the air pressure there increases and an air film is formed between each bearing piece 21 and the rotating shaft 13. At this time, the inner circumferential portion 22a of the Topf oil of each bearing piece 21 is deflected outward by the air pressure, and as a result, tension is applied to the outer circumferential portion 22b of the Topf oil in the circumferential direction of the rotating shaft.
is deformed to reduce its curvature, and the dump oil 23 is compressed by the inner circumferential portion 22a and outer circumferential portion 22b of the top oil 22 and is greatly deflected, so that the elastic force of each bearing piece 21 toward the center of the rotating shaft increases rapidly. This and the fact that there are three wedge spaces 27 result in a high vibration damping effect, and the high frequency vibrations of the rotating shaft 13 are suppressed by the top oil 2 of each bearing piece 21.
2. In addition to the dump oil 23, the squeeze film effect promotes the formation of an air film between the rotating shaft 13 and each bearing piece 21, and an air film is also formed between the top oil 22 and the dump oil 23, resulting in high load capacity.

Note that the number of each bearing piece 21 used is not limited to three.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional device, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view taken along the line -- in FIG. 13...Rotating shaft, 21...Bearing piece, 22...Topfoil, 23...Dumpfoil, 26...
...Support rod.

Claims (1)

[Scope of utility model registration request] A plurality of bearing pieces are formed by interposing corrugated damping oil between the inner and outer circumferential parts of the flat cylindrical topfoil, which is curved into an arc shape with a radius larger than the radius of the rotating shaft. A multi-arc oil bearing in which the bearing pieces are arranged in a row so as to be in contact with the rotating shaft at both ends, and supported by support rods inserted between the inner and outer peripheries of the top oil.