JP2574790Y2 - Heat insulation structure of shaft for bearing inner race - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating structure for a shaft with respect to a bearing inner race.

[0002]

2. Description of the Related Art Conventionally, in a gas turbine engine used in an aircraft, an engine shaft 1 is formed hollow as shown in FIG. 2 to reduce the weight of the engine.

In general, air extracted from a high-pressure compressor of a gas turbine engine flows through a hollow portion 2 of the engine shaft 1.

Further, the bearing 3 supporting the engine shaft 1 is formed by spraying lubricating oil by an oil jet device 4 to perform lubrication and cooling.

[0005]

In the gas turbine engine used for the supersonic aircraft currently being planned, the temperature at the engine inlet becomes high, and the temperature of the air flowing through the hollow portion 2 of the engine shaft 1 is about 500 to 600 ° C. It is expected to be.

For this reason, excessive circumferential stress is generated in the inner race of the bearing 3 due to the thermal expansion of the engine shaft 1, and the lubricating oil sprayed on the bearing 3 by the oil jet device 4 is carbonized when the temperature reaches 200 ° C. or more. As a result, the bearing 3 cannot be lubricated and cooled, so that the bearing 3 may be damaged.

[0007] The present invention has been made in view of the circumstances described above, the hot air
The purpose of the present invention is to provide heat insulation of the shaft with respect to the bearing inner race by preventing the transmission of heat from the shaft to the shaft and the bearing .

[0008]

Means for Solving the Problems To achieve the above object,
Therefore, in the present invention , the inner circumference of the hollow shaft on which the bearing inner race is fitted
From the part located on the side, the other end of the shaft than the inner race
An inner circumferential groove extending to the part located on the side
Along the outer circumference of the inner sleeve that can fit
Is provided with an outer peripheral groove that is substantially equal to the inner peripheral groove, and the inner peripheral groove and the outer peripheral groove
Are facing each other to form an air gap.
It is configured to fit into the hollow shaft .

[0009]

According to the present invention, the inner shaft provided on the inner peripheral portion of the hollow shaft is provided.
The outer circumferential groove and the outer circumferential groove
Suitable for heat insulation without reducing the inner diameter of the inner sleeve.
To form an air gap of a predetermined size, and the air in the air gap is used as a heat insulating layer.
As a result, the propagation of heat from the hollow portion of the shaft to the shaft and the bearing is prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a heat insulating structure of a shaft for a bearing inner race according to the present invention. In FIG. 1, the same components as those in FIG. 2 are denoted by the same reference numerals.

FIG. 1 shows a portion of the inner peripheral portion of the hollow engine shaft 1 corresponding to the outer fitting portion of the bearing inner race 3a.
A circumferential groove 5 having a tapered shape having a required length whose inner diameter gradually increases from the side A to the side B is provided at the center of the outer peripheral portion of the inner sleeve 7 in the longitudinal direction. A peripheral groove 6 having a length compatible with the peripheral groove 5 provided in the inner peripheral portion of the inner sleeve 7 is provided.
The peripheral groove 6 provided on the outer peripheral portion is internally fitted so as to face the peripheral groove 5 provided on the inner peripheral portion of the engine shaft 1, and the peripheral groove 6 and the peripheral groove 5 form a gap 8.

The air in the space 8 acts as a heat insulating layer, and prevents the heat of the high-temperature air flowing through the hollow portion 2 of the engine shaft 1 from being transmitted to the engine shaft 1 and the bearing 3.

In the present embodiment, an inner sleeve 7 is fitted inside the hollow portion 2 of the engine shaft 1 corresponding to the outer fitting portion of the bearing inner race 3a, and a circumferential groove 6 provided on the outer peripheral portion of the inner sleeve 7 and A space 8 is formed by the circumferential groove 5 provided in the inner circumferential portion of the engine shaft 1, and the hollow portion 2 of the engine shaft 1 is formed with respect to the engine shaft 1 and the bearing 3 by the heat insulating action of the air in the space 8.
The heat of the high-temperature air flowing through the shaft 3 is hardly transmitted, so that the engine shaft 1 does not thermally expand, and the lubricating oil sprayed on the bearing 3 by the oil jet device 4 does not carbonize, so that the lubrication of the bearing 3 and Since the cooling can be performed reliably, the bearing 3
Can be prevented from being damaged.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0016]

[Effect of the Invention] As described above, in the present invention,
Inner peripheral groove and inner sleeve provided in the inner peripheral part of hollow shaft
The outer peripheral groove provided on the outer peripheral part of
Form a gap of the size suitable for heat insulation without reducing the inner diameter
Air in the gap as a heat insulating layer in the shaft.
Prevents heat transfer from the cavity to the shaft and bearings
The air flow inside the hollow shaft.
An excellent effect of not being harmed can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a heat insulating structure of a shaft for a bearing inner race of the present invention.

FIG. 2 is a cross-sectional view schematically illustrating an outer fitting portion of a bearing inner race of an engine shaft of a conventional gas turbine engine.

[Explanation of symbols]

Reference Signs List 1 engine shaft ( hollow shaft) 3a bearing inner race 5 peripheral groove (inner peripheral groove) 6 peripheral groove (outer peripheral groove) 7 inner sleeve 8 gap

Claims (1)

(57) [Scope of request for utility model registration] 1. An inner peripheral portion of a hollow shaft on which a bearing inner race is externally fitted is provided at one end of the shaft relative to the inner race.
From the part located on the side, the other end of the shaft than the inner race
An inner circumferential groove extending to the part located on the side
Along the outer circumference of the inner sleeve that can fit
Is provided with an outer peripheral groove that is substantially equal to the inner peripheral groove, and the inner peripheral groove and the outer peripheral groove
Are facing each other to form an air gap.
A heat insulating structure for a shaft with respect to a bearing inner race, wherein the shaft is fitted into a hollow shaft .