JPH081295Y2 - Rolling bearing support device for gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a rolling bearing support device for a gas turbine.

(Prior Art) Conventionally, there has been a rolling bearing support device as shown in, for example, FIG. 2 ("How to select and use rolling bearings", Japanese Standards Association, issued July 20, 1982, No. 1).
(See page 143).

To explain this, in the radial rolling bearing 2, the inner ring 3 is fitted to the rotating shaft 1, the outer ring 4 is fitted and inserted in the bearing housing 7, while the retainer 11 is tightened and fixed to the bearing housing 7 via the bolts 12. As a result, the outer ring 4 is fixed in the thrust direction.

The outer ring 4 of the rolling bearing 2 is compressed in the radial direction when the outer ring 4 is fitted into the bearing housing 7 with a shrink fit, and the clearance between each rolling surface of the outer ring 4 and the inner ring 3 and the ball (rolling element) 10, that is, apparently The radial gap of is decided.

The radial gap and the number of balls 10 are appropriately set according to the load applied to the rolling bearing 2, so that good operability can be obtained.

(Problems to be solved by the invention) By the way, in a gas turbine engine, the load acting on the rolling bearing from the output shaft changes greatly as the engine load fluctuates, so the radial clearance of the rolling bearing is sufficient at maximum output. It is set to be durable.

However, during low load operation such as idling, the radial load received by the rolling bearing from the output shaft is extremely reduced, so the apparent radial gap becomes relatively large, causing slippage (skipping) between the rolling elements and the rolling surfaces. There is a problem that it causes a ding.

The present invention aims to solve these problems.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, in a bearing support device of a gas turbine in which a rolling bearing is mounted on a bearing housing, a sleeve fitted to an outer ring of the rolling bearing by a predetermined shim fit. Is formed of a material having a coefficient of thermal expansion higher than that of the outer ring, and a flange portion that suppresses the end surface of the outer ring is formed on the inner peripheral surface of the sleeve. Gap was formed between the sleeve outer peripheral surface and the housing cylindrical portion inner peripheral wall portion and between the sleeve front end surface and the housing cylindrical portion end surface in the tightened and fixed state.

(Operation) The thermal expansion of the sleeve is prevented because the radial expansion and the axial thermal expansion of the sleeve are not constrained by the gap formed between the sleeve and the inner peripheral wall and the end surface of the housing cylindrical portion into which the sleeve is inserted. It is possible to appropriately change the apparent radial clearance according to the temperature condition associated with. With this, for example, in gas turbine equipment such as a turbine engine, the radial gap is reduced during low-load operation to prevent skidding, and the radial gap is increased during high-load operation as the temperature rises to ensure smooth operability. Can be secured.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the output shaft 1 of the gas turbine engine
Is rotatably supported via a rolling bearing 2 and transmits a turbine output via a pinion reduction gear (not shown).

The radial rolling bearing 2 includes a plurality of cylindrical rollers (rolling elements) 8 between an inner ring 3 and an outer ring 4, the inner ring 2 is fitted to the output shaft 1, and the outer ring 4 is connected to a bearing housing 7 via a sleeve 5. It

The bearing housing 7 is formed with an inner peripheral wall portion 7A into which the sleeve 5 is fitted, and the sleeve 5 is formed with a mounting flange portion 5C at an end outer peripheral portion protruding outward from the inner peripheral wall portion 7A. 5C is fastened and fixed via a plurality of bolts 6 screwed into the bearing housing 7. Further, on the inner peripheral surface 5B of the sleeve 5, there is formed a flange portion 5D for suppressing the end surface of the bearing outer ring 4 in the state where the sleeve 5 is clamped and fixed to the bearing housing 7.

The sleeve 5 is made of a material whose coefficient of thermal expansion is higher than that of the outer ring 4 at a predetermined ratio, and the inner peripheral surface 5B of the sleeve 5 is formed so as to be fitted to the outer peripheral surface 4A of the outer ring 4 by a predetermined shrink fit. To do.

Outer peripheral surface 5A of sleeve 5 and inner peripheral wall of bearing housing 7
A predetermined gap δ is formed between 7A and 7A when the sleeve 5 is fastened to the housing 7 in the cold state, and at the same time, it is also shown between the distal end surface of the sleeve 5 and the housing end surface opposite to this. Make a slight gap as described above. The above-mentioned gaps are provided so as not to restrain the deformation of the sleeve 5 due to the thermal expansion in the radial direction and the axial direction during the operation of the gas turbine at a high temperature.

Based on the above configuration, during low load operation in which the amount of heat transferred from the turbine is small, the coefficient of thermal expansion of the sleeve 5 is relatively small, so the sleeve 5 strongly preloads the outer ring 4 in the radial direction, and the radial gap of the rolling bearing 2 is reduced. Use a small value.
By thus reducing the apparent radial clearance, the cylindrical roller 8 slips on the rolling surfaces of the outer ring 4 and the inner ring 3 even during low load operation in which the radial load applied to the output shaft 1 is small. It is possible to prevent the skidding phenomenon that causes uneven wear.

Under high load operating conditions in which the amount of heat transferred from the turbine increases, the amount of heat transferred from the turbine to the rolling bearing 2 via the output shaft 1 also increases and the temperatures of the outer ring 4 and the sleeve 5 rise, but the outer peripheral surface and the tip surface of the sleeve 5 Bearing housing 7
Since a predetermined gap is secured between the sleeve 5 and the sleeve 5, the sleeve 5 is not bound by the thermal expansion in the radial and axial directions. If the sleeve 5 expands in the axial direction and its front end surface is pressed against the housing 7, not only the fixed state of the outer ring 4 changes but also the deformation of the sleeve 5 in the radial direction is hindered. However, as described above, such a problem can be avoided because a gap allowing axial expansion is also provided in the front end surface of the sleeve 5 as described above.

Since the preload on the outer ring 4 is weakened by the thermal expansion accompanying the temperature rise of the sleeve 5, the rolling surface of the outer ring 4 is reduced.
4B will be expanded in diameter to increase the apparent radial clearance. In this way, at the time of high load operation with a large radial load, ensure a sufficient radial clearance in the rolling bearing 2,
The smooth operability can be maintained.

(Effect of the Invention) As described above, according to the present invention, a sleeve made of a material having a larger coefficient of thermal expansion than the outer ring is fitted to the outer ring by means of a shrink fit, and the sleeve is tightened and fixed to the bearing housing via bolts. Since the gap is formed between the tip surface and the bearing housing, the apparent radial gap can be changed according to the thermal conditions by the preload applied to the outer ring by the sleeve, and as a result, for example, in a gas turbine engine or the like. The operability of the rolling bearing applied to the gas turbine equipment can be effectively maintained over a wide range of operating conditions.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. 1 ... Output shaft, 2 ... Rolling bearing, 3 ... Inner ring, 4 ... Outer ring,
5 ... sleeve, 5B ... sleeve inner peripheral surface, 5D ... flange portion,
6 ... Bolt, 7 ... Bearing housing, 8 ... Cylindrical roller.

Claims (1)

[Scope of utility model registration request] 1. A bearing support device for a gas turbine having a rolling bearing mounted on a bearing housing, wherein a sleeve fitted to the outer ring of the rolling bearing with a predetermined shrinkage is formed of a material having a coefficient of thermal expansion larger than that of the outer ring. A flange portion is formed on the inner peripheral surface of the sleeve to suppress the end surface of the outer ring, and the sleeve is clamped and fixed to the bearing housing via bolts. A support device for a rolling bearing of a gas turbine, characterized in that a gap is formed between the end portion of the sleeve and the end surface of the housing cylindrical portion.