JPS5842656Y2 - gas bearing structure - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improved gas bearing structure that can be applied to ultra-high-speed, high-performance turbomachines, etc., and can improve high-speed stability when used.

Gas bearings supported by damper members such as 01J generally have excellent stability during high-speed rotation and are simple.
For example, it is widely used in dental band pieces, and
It has reached 10,000 rotations.

However, the above-mentioned gas bearing could not be applied as it is to ultra-high-speed, high-performance turbomachinery because of large variations in the dimensional accuracy of damper members such as 01J rings.

In other words, if the gas bearing described above is applied as is to this type of turbomachinery, the center of the bearing and the center of the casing will not match, so the shaft seals, shrouds, gaps, etc. of turbomachinery that require minute gaps must be designed to be large. This would make it impossible to achieve higher performance in turbomachinery.

Therefore, it would be better to improve the dimensional accuracy of the damper member, but
However, the dimensional accuracy has a limit due to the molding process of the damper member, and it is an extremely difficult technique to further increase the dimensional accuracy.

This idea was made in view of the above circumstances, and its purpose is to provide support through damper members such as 01J rings, which are formed using normal processing techniques without any special ultra-precision processing. However, it can be applied to ultra-high-speed, high-performance turbo machinery with small shaft seals, shrouds, and gap caps without any problems, and centering adjustment can be made to ensure stability during high-speed rotation. To provide a gas bearing structure provided with a means with a simple configuration.

A preferred embodiment of this invention will be described below with reference to the drawings.

Reference numeral 1 in the figure is a casing of an ultra-high-speed, high-performance turbomachine such as a radial turbine, and a rotating shaft 2 of the turbomachine is supported via a gas bearing A at the bearing portion of the casing.

This gas bearing A includes a retainer 4 which also serves as a slat bearing and is abutted against a thrust collar part 3 of a rotating shaft 2, and a journal bearing 7 which is supported by this retainer via damper members 5 and 6 made of O-rings. It has a structure that has

That is, the retainer 4 has one end surface in the axial direction (upper end surface in the figure) formed as a thrust bearing surface 4a that abuts against the thrust collar part 3 of the rotating shaft 2, and has an opening diameter on the side of the thrust bearing surface 4a on the inner peripheral wall surface. A step hole 8 with a larger diameter is formed as a space for housing the damper and for introducing gas, and the gas supply hole 9 provided in the casing 1 is connected to the thrust collar part 3.
It has gas introduction branch holes 10 and 11 for connection between and the thrust bearing surface 4a and inside the step hole 8, and a gas exhaust hole 12 for leading out lubricating gas. The structure is such that a diaphragm 16 and a presser plate 17 are each attached concentrically to the opposite surface.

On the other hand, the journal bearing 7 has a gas passage hole 13 passing through the middle part of the peripheral wall, and has annular flanges 14 and 15 integrally formed on the outer peripheral wall and spaced apart from each other with an appropriate gap in the axial direction. .

Such journal bearing 7 is elastically held in step hole 8 of retainer 4 via damper member 5. between the upper step wall of the step hole 8 and the annular collar 14.
The damper member 6 on the lower side of the figure is interposed between the retainer 4 and the journal bearing 7 below the lower annular collar 15 of the journal bearing 7. .

Therefore, the journal bearing 7 having the upper and lower annular flanges 14, 15 has an elastic support structure in which the retainer 4 on the fixed side does not come into direct contact with the diaphragm 16, presser plate 17, etc., which will be described later.

A presser plate 17 is screwed to the lower surface of the retainer 4 via a diaphragm 16 with a plurality of mounting bolts 18 in order to press the lower damper member 6 .

A plurality of adjustment screws 1 are provided on the presser plate 17 as centering adjustment means for compressing the damper member 6 via the diaphragm 16.
9 are provided at approximately equal intervals in the circumferential direction.

Therefore, if it is necessary to improve the concentricity between the casing 1 and the rotating shaft 2, measure the concentricity by an appropriate method and rotate the adjustment screw 19 at a position where the concentricity can be improved. This allows the damper member 6 to be partially compressed in the axial direction between the damper member 6 and the annular collar 15 via the diaphragm 16 using the adjustment screw 19, so that the damper member 6 can compress the journal bearing 7 in the compressed portion. Since the casing 1 is pushed and displaced in the radial direction, the concentricity between the casing 1 and the rotating shaft 2 is improved as intended.

In the above embodiment, the gas sent to the gas supply hole 9 of the casing 1 is transferred to the gas introduction branch hole 10 of the retainer 4.
．． 11, the thrust bearing surface 4a and the journal bearing 7 are lubricated, and the gas is exhausted by passing through the gas exhaust hole 12.

In summary, this invention provides the following various effects.

(1) Although the gas bearing structure uses a damper member such as an OIJ ring, it is equipped with a centering adjustment means that can partially compress the damper member in the axial direction and displace the journal bearing in the radial direction. Since the centering of the journal bearing can be adjusted at any time, variations in the dimensional accuracy (machining accuracy) of the damper member can be corrected by adjusting the centering of the journal bearing.

(2) Therefore, the gas bearing according to this invention can be applied to ultra-high-speed, high-performance turbomachinery without any problems, and can ensure stability even during high-speed rotation.

(3) Furthermore, since the damper member can be formed using normal processing techniques without any special ultra-precision processing, the gas bearing can be manufactured easily and costs can be reduced.

[Brief explanation of the drawing]

The drawing is a sectional view of a gas bearing structure showing a preferred embodiment of this invention. In the figure, 4 is a retainer or thrust bearing, 5 and 6 are damper members, 7 is a journal bearing, and 16 and 19 are a diaphragm and an adjustment screw, which are illustrated as centering adjustment means.

Claims (1)

[Scope of utility model registration request] In a gas bearing structure in which a journal bearing is supported by a retainer or a thrust bearing via a damper member such as an 01J ring, a centering adjustment means is provided for compressing the damper member in the axial direction and displacing the journal bearing in the radial direction. Gas bearing structure featuring