JPH06207533A - Bearing for gas turbine - Google Patents

Abstract

PURPOSE:To provide a bearing for a gas turbine whose damping capacity can not be decreased even when the bearing is applied to a high temperature part. CONSTITUTION:A bearing outer ring 153 and a bearing holder 155 are fitted in each other through a ring 154. However since recessed parts and protrusion parts are alternately formed on the ring 154, a damping effect by a spring force is produced at the ring 154 itself. Further, a flow passage is formed between the bearing outer ring 153 and the bearing holder 155, the ring 154 is cooled by means of a cooling medium, such as lubricating oil, and thermal deterioration of the ring 154 hardly occurs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine bearing, and more particularly to a gas turbine bearing having a high combustion temperature.

[0002]

2. Description of the Related Art A gas turbine has a large specific output,
Practical application as an automobile engine has been promoted because of the low content of nitrogen oxides in the exhaust gas. Since the output of the gas turbine increases as the combustion gas temperature increases, it is considered to use ceramics as the structural material of the gas turbine and set the combustion gas temperature to 1300 to 1400 ° C.

Since the rotational speed of such a ceramic gas turbine reaches about 80,000 rpm, it is necessary to provide a mechanism for absorbing the rotational vibration at the contact portion between the bearing holding the rotating shaft and the supporting member of the bearing. is there. The most common method is to use a squeeze film damper that absorbs rotational vibration by supplying damping oil, such as lubricating oil, to the gap between the outer circumference of the bearing and the support member, but if the gap is small. Has a small allowable vibration amplitude,
When the gap is large, the oil film is less likely to be formed, and the damping effect is lost.

In order to solve this problem, two elastic sealing rings are axially inserted between the bearing and the support member to secure a damping oil flow path between the two elastic sealing rings.
Also, a method has been proposed in which a damping oil flow path is engraved on the outer periphery of the bearing and damping oil supply holes are provided above and below the support member (Actual Development No. 61-6021).

[0005]

However, since damping oil is not supplied to the outer circumference of the elastic sealing ring, the elastic sealing ring is thermally deteriorated and the damping effect is reduced. The present invention has been made in view of the above problems,
It is an object of the present invention to provide a gas turbine bearing that does not deteriorate in damping capacity even when applied to a high temperature part.

[0006]

In a bearing for a gas turbine according to the present invention, a ring in which irregularities are alternately formed in the radial direction is inserted between a bearing outer ring and a bearing support member, and the bearing outer ring and the bearing are formed. A cooling medium for the ring is supplied between the cooling medium and the support member.

[0007]

In the bearing for a gas turbine according to the present invention, the ring in which irregularities are alternately formed in the radial direction is inserted between the bearing outer ring and the bearing support member, and the vibration is damped by the spring force of the ring itself. At the same time, the flow path of the cooling medium is secured between the bearing outer ring and the bearing support member, the cooling medium is supplied between the outer circumference of the ring and the bearing support member, and the outer circumference of the ring is cooled.

[0008]

1 is a cross-sectional view of a gas turbine to which a gas turbine bearing according to the present invention is applied. The combustion gas generated in the combustor passes through the scroll 11 and the impeller 12
Is discharged to the exhaust passage 13.

The rotating force generated by the impeller 12 is the rotating shaft 1.
4 is transmitted to a compressor or a load (not shown) by 4, and the rotary shaft 14 is supported by a bearing portion 15. In the ceramic gas turbine in which the scroll 11, the impeller 12, and the rotating shaft 14 are made of ceramic,
Since the combustion gas temperature is 1300 to 1400 ° C, the temperature of the bearing portion 15 rises to about 800 ° C. Further, since the rotation speed is about 80,000 rpm, the bearing portion 15 is required to have high speed rotation resistance and high temperature resistance.

FIG. 2 is an enlarged view of the bearing portion 15. The bearing 150 is composed of an inner ring 151, a roller 152 and an outer ring 153 which are fitted into the rotary shaft 14 by a warm fit. A ring 154 is fitted around the outer ring 153,
Further, it is fitted into the bearing holder 155.

The assembled bearing holder 155 is fitted into a metal back plate 156 by a so-called spigot and fixed by bolts 157. FIG. 3 is a front view of a ring 154 fitted on the outer periphery of the outer ring 153, and recesses 1541 and projections 1542 are alternately provided at four places. FIG. 4 is a front view and a sectional view of the bearing holder 155, showing the bearing 150 and the ring 154 in the direction of arrow A.
Is fitted into the bearing 150 and the ring 1 with the collar 1551.
Hold 54. The groove 155 formed in the collar 1551
2 functions as an outlet for the cooling medium of the ring 1551.

FIG. 5 is an assembly view of the bearing 150, the ring 154 and the bearing holder 155. The recess 1541 of the ring 154 contacts the outer ring 153 of the bearing, and the projection 1542 of the ring 154 contacts the inner wall of the bearing holder 155. A predetermined gap is secured between the bearing outer ring 153 and the bearing holder. For example, the ring 154 has a thickness of 0.5 m.
It is a metal ring having elasticity of about m, and the height of the unevenness is formed to be about 0.5 mm like the thickness.

Therefore, due to the unevenness, a spring force is generated in the ring 154, the vibration of the bearing 150 is absorbed by this spring force, and the vibration of the rotating shaft 14 is suppressed from being transmitted to the bearing holder 155. FIG. 6 is a cross-sectional view and a side view of the back plate 156. A ring-shaped lubricating oil groove 158 is formed at a position facing the ring 154, and a branch flow passage 160 branched from the bearing lubricating oil supply passage 159 is formed. Lubricating oil is supplied via.

This lubricating oil flows axially along the opposing ring 154 to cool the ring 154. That is, the gap functions as a flow path for the lubricating oil that is the cooling medium of the ring, the heat of the ring 154 is removed, and “sagging” of the spring force of the ring 154 is prevented.

[0015]

According to the gas turbine bearing of the present invention, since the ring having the irregularities alternately formed in the radial direction is inserted between the bearing outer ring and the bearing support member, vibration of the rotating shaft is prevented. It is possible to suppress the vibration being transmitted to the bearing holder by being damped by the spring force of the ring.

Further, since a gap is secured between the bearing and the bearing holder and the ring is cooled by the lubricating oil supplied to this gap, the spring force of the ring is less likely to be thermally deteriorated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a gas turbine.

FIG. 2 is an enlarged view of a gas turbine bearing portion.

FIG. 3 is a front view of a ring.

FIG. 4 is a front view and a sectional view of a bearing holder.

FIG. 5 is an assembly drawing of a bearing, a ring and a bearing holder.

FIG. 6 is a cross-sectional view and a side view of a back plate.

[Explanation of symbols]

 11 ... Scroll 12 ... Impeller 13 ... Exhaust path 14 ... Rotating shaft 15 ... Bearing part 150 ... Bearing 151 ... Inner ring 152 ... Roller 153 ... Outer ring 154 ... Ring 155 ... Bearing holder 156 ... Back plate 157 ... Bolt 158 ... Lubricating oil groove 159 … Bearing lubricating oil supply channel 160… Branch channel

Claims (1)

[Claims] 1. A ring in which irregularities are alternately formed in the radial direction is inserted between a bearing outer ring and a bearing support member, and the ring cooling medium is supplied between the bearing outer ring and the bearing support member. Bearings for gas turbines.