JP2003269192A - Bearing device of radial drive shaft for gas turbine engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device capable of increasing a critical speed of a radial drive shaft for a gas turbine engine for transmitting rotational motive power of a turbine shaft of a gas turbine engine to an accessory gear box integrally arranged in the gas turbine engine, and capable of restraining skidding of an intermediate bearing. <P>SOLUTION: This bearing device 100 of the radial drive shaft 10 transmits the rotational motive power of the turbine shaft 22 of the gas turbine engine GE1 to the accessory gear box 53, and has a bearing 20 for supporting one end part side of the radial drive shaft 10 on the turbine shaft 22 side, a bearing 30 for supporting the other end part side of the radial drive shaft 10 on the accessory gear box 53 side, and the intermediate bearing 40 for supporting the radial drive shaft 10 in an intermediate part of the radial drive shaft 10. An axial position of the intermediate bearing 40 is made eccentric to a straight line for connecting the axis of the bearings 20 and 30. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the above-mentioned gas turbine engine in which the rotational power of the turbine shaft of a gas turbine engine, which obtains a propulsive force or a rotational force by ejecting a high-temperature and high-pressure combustion gas, is integrally provided. The present invention relates to a bearing device for a radial drive shaft for a gas turbine engine, which transmits to an accessory gear box, and in particular, the position of the intermediate bearing of the radial drive shaft is slightly eccentric so that a small radial gap in the intermediate bearing is on one side. The present invention relates to a bearing device that is biased.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional gas turbine engine G.
It is sectional drawing which shows schematic structure of E2, and is sectional drawing which shows the structure of the periphery of the radial drive shaft 10 provided in the gas turbine engine GE2.

The gas turbine engine GE2 is used in an aircraft as a jet engine, for example,
It is an engine that obtains propulsive force or rotational force by ejecting high-temperature and high-pressure combustion gas.

The gas turbine engine GE2 includes an engine outer cylinder 51 and a strut 5 inside the engine outer cylinder 51.
4 and a hollow engine case 52 integrally and substantially concentrically provided with the engine outer cylinder 51 via the base 4. An annular engine flow passage 62 is formed inside the engine case 52, and an annular bypass flow passage 61 is formed between the engine outer cylinder 51 and the engine case 52.

At the inner front part of the engine case 52 (portion on the upstream side as viewed in the gas flow direction), the engine flow path 6 is provided.
The front support frame 55 separates the engine case 52 from each other.
The front support frame 55 rotatably supports the low-pressure turbine shaft 21 via a bearing, and the front support frame 55 is a hollow high-pressure turbine shaft via a bearing. 22 is supported so as to be rotatable and concentric with the low-pressure turbine shaft 21.

At the front end side of the low-pressure turbine shaft 21, a fan 21A for sending air into the engine flow path 62 and the bypass flow path 61 is provided.

A low-pressure compressor 70 is provided on the upstream side of the engine flow path 62. The low-pressure compressor 70 compresses air at a low pressure and is on the downstream side (downstream when viewed from the gas flow direction, the right side of FIG. 2). ) Is sent to.

The low-pressure compressor 70 has an annular blade support member 72 integrally provided on the low-pressure turbine shaft 21 on the downstream side of the fan 21A, and an outer peripheral portion of the blade support member 72 along the engine flow path 62. A plurality of low-pressure compression blade rows 71 provided
And a plurality of low-pressure compression vane rows 73 alternately provided with a plurality of stages of low-pressure compression blade rows 71 along the engine flow path 62 inside the engine case 52.

The low-pressure compression blade row 71 is composed of a plurality of low-pressure compression blades provided in the circumferential direction, and the low-pressure compression vane row 73 is composed of a plurality of low-pressure compression vanes provided in the circumferential direction. It will be.

Low pressure compressor 70 in engine flow path 62
A high pressure compressor 80 is provided on the downstream side of the low pressure compressor 80, and the low pressure compressor 80 sends the low pressure compressed air of the low pressure compressor 70 to the downstream side while compressing it under high pressure.

The high-pressure compressor 80 includes a plurality of stages of high-pressure compression moving blade rows 81 provided on the high-pressure turbine shaft 22 along the engine flow path 62, and inside the engine case 52, along the engine flow path 62. A plurality of high-pressure compression blade rows 81 and a plurality of high-pressure compression vane rows 82 provided alternately are provided.

Here, the high-pressure compression blade row 81 is composed of a plurality of high-pressure compression blades provided in the circumferential direction, and the high-pressure compression vane row 82 is composed of a plurality of high-pressure compression vanes provided in the circumferential direction. It will be.

High pressure compressor 80 in engine flow path 62
An annular combustion chamber (not shown) is provided on the downstream side of
This combustion chamber burns fuel in compressed air to generate high-temperature and high-pressure combustion gas.

A high pressure turbine (not shown) is provided on the downstream side of the combustion chamber in the engine flow path 62. The high pressure turbine obtains a rotational force by expansion of high temperature and high pressure combustion gas from the combustion chamber. The high pressure turbine shaft 22 is driven to rotate.

The high-pressure turbine has a high-pressure turbine shaft 22.
A plurality of stages of high-pressure turbine rotor blades (not shown) provided along the engine flow path 62 and rotated by high-temperature and high-pressure combustion gas, and inside the engine case 52 along the engine flow path 62. High-pressure turbine vane rows of multiple stages (not shown) alternately provided with the high-pressure turbine blade rows of
And.

Here, the high-pressure turbine blade row is composed of a plurality of high-pressure turbine blades provided in the circumferential direction, and the high-pressure turbine vane row is composed of a plurality of high-pressure turbine blades provided in the circumferential direction. It will be.

A low pressure turbine (not shown) is provided downstream of the high pressure turbine in the engine flow path 62,
This low-pressure turbine obtains a rotational force by the expansion of the high-temperature and high-pressure combustion gas from the combustion chamber, and the low-pressure turbine shaft 21
Is driven to rotate.

The low-pressure turbine has a low-pressure turbine shaft 21.
A plurality of stages of low-pressure turbine rotor blades (not shown) that are provided along the engine flow path 62 and that are rotated by high-temperature and high-pressure combustion gas, and inside the engine case 52 along the engine flow path 62. Row of low-pressure turbine stationary blades (not shown) alternately provided with the high-pressure turbine blade rows of
And.

Here, the low pressure turbine rotor blade row is composed of a plurality of low pressure turbine rotor blades provided in the circumferential direction, and the low pressure turbine stator blade row is composed of a plurality of low pressure turbine stator blades provided in the circumferential direction. It will be.

Further, the gas turbine engine GE2 includes
A mechanism is provided for taking out the rotational force of the high-pressure turbine shaft 22 from the accessory gear box 53 provided in the engine outer cylinder. Next, the above mechanism will be described. A hydraulic pressure generator (not shown) and a power generator (not shown) are connected to the accessory gear box 53.

FIG. 3 shows the rotational force of the high-pressure turbine shaft 22,
It is a figure which shows the conventional mechanism for taking out even the accessory gear box 53 provided in the outer peripheral surface of the engine outer cylinder 51, and is an enlarged view of the III section of FIG.

The above-mentioned conventional mechanism for extracting the rotational force of the high-pressure turbine shaft 22 to the accessory gear box 53 provided on the outer peripheral surface of the engine outer cylinder 51 is the front end side (upstream side end) of the high-pressure turbine shaft 22. Part side) on the outer peripheral part,
Bevel gear 2 integrally provided on the high-pressure turbine shaft 22
3, a bevel gear 24 that meshes with the bevel gear 23 and transmits the rotational force of the bevel gear 23, and the high-pressure turbine shaft 2
2 is fitted with the bevel gear 24 at one end side of the bevel gear 2
Radial drive shaft 10 transmitting the rotational force of 4
And a bevel gear 31 that is fitted to the radial drive shaft 10 at the other end side (accessory gear box 53 side) of the radial drive shaft 10 to transmit the rotational force of the radial drive shaft 10, and the accessory gear box 53, A bevel gear 55 that meshes with the bevel gear 31 and transmits the rotational force of the bevel gear 31 to the accessory gear box 53 is provided.

Here, the bevel gear 24, the radial drive shaft 10, and the bevel gear 31 are connected to the engine outer cylinder 51 and the engine case 5 via the conventional bearing device 200.
2. The front support frame 55 is rotatably provided.

That is, the bevel gear 24 and the one end side of the radial drive shaft 10 are on the high pressure turbine shaft 22 side (inside the gas turbine engine GE2) via the turbine side bearing 20 which is the first bearing. The bevel gear 31 and the other end of the radial drive shaft 10 are rotatably provided with respect to the front support frame 55, and are the second bearings on the accessory gear box 53 side (outside of the gas turbine engine GE2). Through the accessory gearbox side bearing 30, the engine outer cylinder 5
1. The radial drive shaft 10 is rotatably provided with respect to 1, and a substantially intermediate portion of the radial drive shaft 10 is provided with an intermediate bearing 140.
It is provided rotatably with respect to the engine case 52.

Further, the turbine side bearing 20 has bearings 25A and 25 supported by a front support frame 55.
B, and the bevel gear 2 provided on the high-pressure turbine shaft 22 by these bearings 25A and 25B.
Hollow boss 2 of bevel gear 24 meshing with 3
4A is rotatably supported.

The radial drive shaft 10 is inserted in the spline hole 26 formed in the boss portion 24A.
The spline 11 formed on the above-mentioned one end side (lower side in FIG. 1) is fitted.

The accessory gearbox side bearing 30 is
Bearing 32 provided integrally with engine outer cylinder 51 and supported by adapters 56A and 56B for integrally fixing accessory gear box 53 to the engine outer cylinder.
A, a bearing 32B and a bearing 32C are provided, and the hollow boss portion 31A of the bevel gear 31 meshing with the bevel gear 55 provided in the accessory gear box 55 is freely rotatable by these bearings 32A, 32B and 32C. It is supported.

The radial drive shaft 10 is inserted in the spline hole 33 formed in the boss portion 31A.
The spline 12 formed on the other end side (upper side in FIG. 1) of the above is fitted.

The intermediate bearing 140 includes the engine case 52.
It is constituted by, for example, a cylindrical roller bearing 41 fixed to.

Here, the shaft center 27 of the turbine side bearing 20
And the shaft center 34 of the accessory gearbox side bearing 30
And the shaft center 142 of the intermediate bearing 140 are arranged concentrically.

The radial drive shaft 10 is
At the bypass path 61, it is covered by struts 54 holding the engine case 52, and at engine path 62, it is covered by struts (not shown) holding the front support frame 55.

The reason why the intermediate bearing 140 is provided is that the radial drive shaft 10 has a length longer than its diameter.
Is rotated at an extremely high speed (for example, 20,000 rpm), only the turbine-side bearing 20 provided on the one end side of the drive shaft 10 and the accessory gearbox-side bearing 30 provided on the other end side of the drive shaft 10 This is because, in the support, the drive shaft 10 may be damaged or the like beyond the critical speed of the drive shaft 10.

[0033]

By the way, in the conventional bearing device 200, as described above, when the radial drive shaft 10 rotates at a high speed, the drive shaft 10 is rotated.
The intermediate bearing 140 is provided so that the speed does not exceed the critical speed. A bearing 41, which is, for example, a cylindrical roller bearing, is used for the intermediate bearing 140 in consideration of ease of assembling the drive shaft 10. The bearing 41 includes an inner ring 41A, an outer ring 41B, a roller 41C, and the like.

Here, the inner diameter of the inner ring 41A is the outer diameter of the drive shaft 10 and is slightly smaller than the outer diameter of the portion fitted to the inner ring 41A. That is, the drive shaft 10 is tightly fitted to the inner ring 41A, for example, and the distance between the drive shaft 10 and the inner ring 41A is suppressed to zero.

The outer diameter of the outer ring 41B is slightly larger than the inner diameter of the bearing holding hole 52A provided in the engine case 52 and holding the outer ring 41B of the bearing 41. That is, the outer ring 41 of the bearing 41
B is tightly fitted in the bearing holding hole 52A.

Therefore, there is no gap between the drive shaft 10 and the inner ring 41A of the bearing 41, and between the outer ring 41B of the bearing 41 and the engine case 52.

On the other hand, the bearing 41 has a slight radial bearing gap in the steady operation state of the bearing 40. Here, the radial bearing gap means a minute movement amount of the inner ring 41A in the radial direction when the inner ring 41A is slightly moved in the radial direction with the outer ring 41B fixed.

The reason why the slight radial bearing gap is provided as described above is as follows.

Theoretically, the life of the bearing is maximized when the running clearance, which is the bearing clearance in the steady running state of the bearing, is slightly negative. However, in practice, it is difficult to always maintain this operating state. If the outer diameter of the roller expands and the amount of the negative bearing gap increases due to some change in the operating conditions (for example, the bearing temperature rises), it will cause a significant decrease in life and further heat generation. In the above, the bearing gap is set to be slightly larger than zero.

As described above, in the intermediate bearing 40,
When there is an operating clearance which is a bearing clearance in a steady operation state, a minute clearance exists between the drive shaft 10 and the engine case 52, and the minute clearance reduces the critical speed of the radial drive shaft 10. There's a problem.

Further, since the intermediate bearing 41 has a low load, there is a problem in that skidding (wear due to revolving slip occurring in a high speed and low load roller bearing) is likely to occur.

The present invention has been made in view of the above problems, and a gas turbine for transmitting the rotational power of a turbine shaft of a gas turbine engine to an accessory gear box integrally provided in the gas turbine engine. An object of the present invention is to provide a bearing device capable of increasing the critical speed of the radial drive shaft 10 for an engine and suppressing the occurrence of skidding of the intermediate bearing 41.

[0043]

The present invention according to claim 1 is a radial structure for transmitting rotational power of a turbine shaft of a gas turbine engine to an accessory gearbox provided in the gas turbine engine. In the drive shaft bearing device, a first bearing that supports one end side of the radial drive shaft on the turbine shaft side and a second bearing that supports the other end side of the radial drive shaft on the accessory gear box side. A bearing and an intermediate bearing that supports the radial drive shaft at an intermediate portion of the radial drive shaft are provided, and the axial center position of the intermediate bearing is set to a straight line connecting the axial centers of the first and second bearings. The eccentricity of the intermediate bearing to deviate the bearing clearance of the intermediate bearing to one side in the radial direction. A bearing device for a radial drive shaft for turbine engine.

According to a second aspect of the present invention, in the radial drive shaft bearing device for a gas turbine engine according to the first aspect, the intermediate bearing comprises:
A cylindrical roller bearing provided in the case of the gas turbine engine, wherein the first bearing is spline-fitted with a gear rotatably provided in the case of the gas turbine engine to provide the radial bearing. A gas turbine that is a bearing that supports the drive shaft, and the second bearing is a bearing that supports the radial drive shaft by spline-fitting with a gear that is rotatably provided in the accessory gear box. A bearing device for a radial drive shaft for an engine.

[0045]

1 is a diagram showing a schematic configuration of a bearing device 100 according to an embodiment of the present invention.

A device receiver for the radial drive shaft 10 for the gas turbine engine, which transmits the rotational power of the turbine shaft 22 of the gas turbine engine GE1 to an accessory gear box 53 which is integrally provided on the outer cylinder 51 of the gas turbine engine GE2. The device 100 is configured substantially the same as the conventional bearing device 200 except for a part.

Therefore, in FIG. 1, the components having the same functions as those of the bearing device 200 are designated by the same reference numerals as those used in the description of the bearing device 200. Then, in the following description, the bearing device 200
The description of the components overlapping with those of the bearing device 200 will be omitted.
The different components will be described.

In the bearing device 100, one end of the radial drive shaft 10 on the high pressure turbine shaft 22 side is rotatably provided on the front support frame 55 via the turbine shaft side bearing 20, and the accessory gear box 53 of the drive shaft 10 is provided. The other end side of the drive shaft 10 is rotatably provided to the adapters 56A and 56B fixed to the engine outer cylinder 51 via the accessory gearbox side bearing 30. It is the same as the bearing device 200 in that it is rotatably provided in the engine case 52 via the bearing 40.

However, in the conventional bearing device 200, the shaft center 27 of the turbine side bearing 20, the shaft center 34 of the accessory gear box side bearing 30, and the shaft center 42 of the intermediate bearing 40 coincide with each other and are concentric with each other. On the other hand, in the bearing device 100, the position of the bearing holding hole 52A provided in the engine case 52 is slightly shifted, and the shaft center 27 of the turbine side bearing 20 and the accessory gearbox side bearing 30 are provided. The position of the shaft center 42 of the intermediate bearing 40 is slightly decentered by the dimension L1 from the shaft center 34 of FIG.

In FIG. 1, the conventional bearing device 200 is used.
The drive shaft position 10 </ b> A in FIG.

Here, the radial drive shaft 10
Is straight in the axial direction when no external force is applied to it (for example, before assembly), and when assembled to the bearing device 100, the intermediate bearing 40 bends so that the central portion slightly bends.

The eccentricity (amount of eccentricity) L11 is generally determined by the outer diameter, inner diameter, length, material, rotational speed, operating temperature, etc. of the hollow radial drive shaft.

That is, the amount of eccentricity L11 causes the bearing gap of the intermediate bearing 40 to be offset in one of the radial directions, and further, the shear stress generated in the drive shaft 10 by the torque transmitted by the drive shaft 10 and the drive shaft 10 are caused. A combination stress with the maximum bending stress generated in the substantially central portion of the drive shaft 10 due to the eccentricity of the intermediate bearing 40, and a repetition number of the combination stress generated by the rotation of the drive shaft 10,
Material of drive shaft 10 and drive shaft 10
Also, the drive shaft 10 is determined so as not to be fatigue-damaged by the temperature change and the like.

The above-mentioned shear stress slightly changes in accordance with a slight change in the outer diameter of the drive shaft 10. However, the torque transmitted by the drive shaft 10 causes a twist that is substantially evenly generated in the entire axial length of the drive 10. The maximum bending stress is generated substantially uniformly over the entire length of the drive shaft 10 in the axial direction according to the moment, and the maximum bending stress is generated according to the maximum bending moment generated in the substantially central portion of the drive shaft 10 due to the eccentricity of the intermediate bearing 40 of the drive shaft 10. It occurs almost at the center of the drive shaft 10.

According to the bearing device 100, since the drive shaft 10 which is originally straight is supported by the eccentric intermediate bearing 40 before being assembled, in the intermediate bearing 40, the drive is performed in the direction in which the intermediate bearing is eccentric. The restoring force of the shaft 10 is always applied, and the inner ring of the bearing of the intermediate bearing 40 is constantly urged to the outer ring through the rollers in the eccentric direction. Therefore, the bearing gap of the intermediate bearing 40 is biased to one side in the radial direction, and the critical speed of the drive shaft 10 when the drive shaft 10 rotates increases.

Further, since the intermediate bearing is eccentric, a load of a certain level or more is always generated on the intermediate bearing 41, so that the occurrence of skidding on the intermediate bearing 41 can be suppressed.

In the bearing device 100, the radial drive shaft 10 obtains rotational power from the high-pressure turbine shaft 22. However, instead of the high-pressure turbine shaft 22, the low-pressure turbine shaft 21 obtains rotational power. Good.

[0058]

According to the present invention, the danger of the radial drive shaft 10 for a gas turbine engine for transmitting the rotational power of the turbine shaft of the gas turbine engine to an accessory gear box integrally provided in the gas turbine engine. This has the effect of increasing the speed and suppressing the occurrence of skidding of the intermediate bearing 41.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a bearing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of a conventional gas turbine engine, and is a cross-sectional view showing a configuration around a radial drive shaft provided in the gas turbine engine.

3 is a view showing a conventional mechanism for taking out the rotational force of the high-pressure turbine shaft to an accessory gear box provided on the outer peripheral surface of the engine outer cylinder, and is an enlarged view of a portion III in FIG.

[Explanation of symbols]

GE1 ... Gas turbine engine, 100 ... Bearing device, 10 ... Radial drive shaft, 11, 12, 26, 33 ... Spline, 20 ... Turbine shaft side bearing, 21 ... Low pressure turbine Shaft, 22 ... High-pressure turbine shaft, 24, 31 ... Bevel gear, 24A, 31A ... Boss portion, 25A, 25B, 32A, 32B, 32C, 41 ... Bearing, 30 ... Accessory gear box Side bearing, 40 ... Intermediate bearing, 53 ... Accessory gear box, L11 ... Eccentric amount.

Claims (2)

[Claims] 1. A radial drive shaft bearing device for transmitting rotational power of a turbine shaft of a gas turbine engine to an accessory gear box provided in the gas turbine engine, wherein the radial drive shaft is provided on the turbine shaft side. A first bearing that supports one end of the radial drive shaft; a second bearing that supports the other end of the radial drive shaft on the accessory gear box side; and a radial drive shaft on the middle part of the radial drive shaft. An intermediate bearing for supporting the intermediate bearing, and the axial center position of the intermediate bearing is eccentric with respect to a straight line connecting the axial centers of the first and second bearings, whereby the bearing gap of the intermediate bearing is radial direction. Radial dry for gas turbine engine characterized by being biased to one side The shaft of the bearing device. 2. The radial drive shaft bearing device for a gas turbine engine according to claim 1, wherein the intermediate bearing is a cylindrical roller bearing provided in a case of the gas turbine engine, and the first bearing is A bearing that supports the radial drive shaft by spline fitting with a gear that is rotatably provided with respect to the case of the gas turbine engine,
A radial drive for a gas turbine engine, wherein the second bearing is a bearing that supports the radial drive shaft by spline-fitting with a gear that is rotatably provided in the accessory gear box. Shaft bearing device.