JP4192661B2 - Gas turbine vertical shaft support structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a fan frame strut through which a vertical axis for driving an accessory gearbox passes.
[0002]
[Prior art]
FIG. 3 is a schematic cross-sectional view of an aircraft gas turbine engine. In the figure, 1 is a fan casing and 2 is a core. The fan casing 1 is supported from an aircraft body such as an aircraft wing, and the core 2 is supported from the fan casing 1. The core 2 includes a compressor 3, a combustion chamber 4, and a turbine 5. The compressor 3 includes a fan 3a, a low pressure compressor 3b, and a high pressure compressor 3c. The turbine 5 includes a high pressure turbine 5a and a low pressure turbine 5b. The air flowing in from the front is pressurized by the fan 3a, and a part thereof becomes a bypass flow (secondary air) as shown by an arrow 7 and flows out from the rear through the bypass duct 6 outside the core 2, and the remainder As shown by the arrow 8, it becomes a core flow (primary air), is further pressurized by the low-pressure compressor 3b and the high-pressure compressor 3c, is heated in the combustion chamber 4 and becomes high-temperature and high-pressure, and the high-pressure turbine 5a and the low-pressure turbine 5b. After rotating, it flows out from behind. The product of the flow rate and flow velocity of primary air and secondary air discharged from the rear of the engine is the thrust of the aircraft.
[0003]
As shown in the figure, the fan 3a and the low-pressure compressor 3b are driven by the low-pressure turbine 5b via the fan drive shaft 11, and the high-pressure compressor 3b is driven by the high-pressure turbine 5a via the high-pressure compressor drive shaft 10. The
[0004]
The ratio of the secondary air volume to the primary air volume is called the bypass ratio. However, in the case of an aircraft engine, since it flies at a subsonic speed, this bypass ratio is set as high as about 5 to 7 in order to save fuel consumption. ing. In addition, 9 is a fuel.
[0005]
4A is a cross-sectional view taken along a portion of the compressor 3 in FIG. 3, and FIG. 4B is a cross-sectional view of a strut. In the figure, reference numeral 12 denotes a fan frame constituting the core 2. Reference numeral 12 a denotes a strut that forms a part of the fan frame 12. The fan frame 12 may be cast integrally with the strut 12a, but may be integrated by welding at a welded portion indicated by a dotted line 12b. The fan frame 12 is supported from the fan casing 1 via struts 12a. As shown in FIG. 4B, the strut 12a is hollow and has a streamlined or triangular shape.
[0006]
Accessories and gearboxes directly connected to the engine to drive auxiliary equipment such as power generators for supplying electricity to the aircraft's fuselage and electric pumps and hydraulic pumps for supplying hydraulic pressure to the hydraulic devices ( Accessory Gearbox, hereinafter referred to as AGB). AGB is a bevel gear (bevel gear) and a vertical axis (hereinafter referred to as RDS) from the high-pressure compressor drive shaft 10. The vertical axis means a radial axis, and may be, for example, a horizontal direction. .) Driven through. The AGB is attached to the outside of the fan casing 1 so that inspection and replacement are easy.
[0007]
As described above, since the bypass ratio is high in the case of a passenger aircraft engine, the diameter of the fan casing 1 is large. Accordingly, the RDS becomes longer and vibrations are likely to occur, so that it is supported by the intermediate bearing.
[0008]
FIG. 5 is a cross-sectional view showing an example of the arrangement of RDS intermediate bearings. In the figure, 20 is an RDS, and a male spline 20a is provided at the tip. Reference numeral 21 denotes a bevel gear attached to the high-pressure compressor drive shaft 10, and reference numeral 21a denotes a female spline. As shown in the figure, the RDS passes through the inside of one of the plurality of fan frame struts 12a. Reference numeral 22 denotes a long cylindrical housing, which is attached to the fan casing 1 via a bracket 22a having an annular shape, and holds an intermediate bearing 24 at the tip thereof. Reference numeral 23 denotes a stopper, which surrounds the lower end of the housing 22 on the outside and suppresses vibrations thereof.
[0009]
FIG. 6 is a sectional view showing another arrangement example of the intermediate bearing of the RDS. Note that description of parts common to FIG. 5 is omitted. In the figure, reference numeral 25 denotes a housing for the intermediate bearing 24. The base end portion of the housing 25 is attached to the side surface of the strut 12 a, and the attachment portion is located inside the fan frame 12 that partitions the bypass duct 6 and the core 2.
[0010]
FIG. 7 is a drawing showing a method for assembling the RDS 20. In the figure, 24a is an outer ring of the intermediate bearing 24, 24b is a roller, and 24c is an inner ring. Reference numeral 25 denotes a housing, and 26 denotes a snap ring. As shown in the figure, the outer ring 24 a and the roller 24 a of the bearing 24 are attached in the housing 25. Further, the inner ring 24c of the bearing 24 is attached to an appropriate position of the RDS 20 with a simplification. When the RDS 20 is moved in the direction of the arrow 27 and the male spline 20a at the tip of the RDS 20 passes through the roller 24b of the bearing 24 and is fitted into the female spline 21a of the bevel gear-21, the inner ring 24c of the bearing 24 is within the roller 24b. It is supposed to fit in.
[0011]
[Problems to be solved by the invention]
However, the bearing housings 22 and 25 as shown in FIGS. 5 and 6 are both cantilevered, and since the housing 22 is particularly long, it is difficult to obtain a large vibration resistance rigidity for suppressing RDS vibration. .
[0012]
The present invention has been devised in view of such problems of the prior art, and a fan frame strut of a gas turbine capable of obtaining a large vibration resistance rigidity by supporting an intermediate bearing housing from the fan frame strut all around. The purpose is to provide.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a gas turbine fan frame strut according to the present invention passes through a vertical axis that drives an accessory gearbox among a plurality of fan frame struts that support a gas turbine core from a fan casing. A fan frame strut, which is divided in the middle in the longitudinal direction, and the divided portions are assembled with the intermediate bearing housing of the vertical shaft interposed therebetween.
[0014]
Next, the operation of the present invention will be described. The fan frame strut through which the RDS passes is divided in the middle in the longitudinal direction, and is assembled by sandwiching the housing of the intermediate bearing, so that the housing is supported all around the strut. Therefore, a large vibration resistance rigidity can be obtained, and the vibration of RDS can be effectively suppressed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an arrangement of intermediate bearings using a fan frame strut of a gas turbine of the present invention. In this figure, the same reference numerals are used for portions common to FIG. 5 or FIG. In the figure, reference numeral 30 denotes a fan frame strut according to the present invention. The fan frame strut 30 is one of a plurality of fan frame struts 12a that support the core of the gas turbine, and passes through a vertical axis (RDS) 20 that drives an AGB (not shown). The fan frame strut 30 is divided in the middle in the longitudinal direction, and is assembled by bringing the upper and lower flanges 30a and 30b into contact with each other and tightening them with bolts and nuts. A bearing housing 30c having a cylindrical shape and an inwardly facing flange 30d is attached to the lower flange 30b, and an intermediate bearing 24 is fitted in the housing 30c.
[0016]
FIG. 2 is a sectional view showing an example in which the strut of the present invention is actually applied. In this case, the strut 30A is solid and has a hole 30h through which the RDS 20 passes. Since it is heavy when it is solid, it cannot be applied to an aircraft engine, but it can be applied to a gas turbine for power generation using an aircraft engine conversion type. The upper strut 30f has a diameter smaller than that of the lower strut 30g, and a flange 30e projects from the lower end of the upper strut 30f, and is connected to the lower strut 30g by a bolt at that portion. The method for assembling the RDS 20 is the same as that shown in FIG.
[0017]
Next, the operation of this embodiment will be described. The fan frame strut 30 through which the RDS 20 passes is divided in the middle in the longitudinal direction and is assembled by sandwiching the housing 30a of the intermediate bearing 24, so that the housing is supported from the strut 30 all around. Therefore, large vibration resistance rigidity can be obtained, and vibration of the RDS 20 can be effectively suppressed.
[0018]
The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.
[0019]
【The invention's effect】
As described above, the fan frame strut of the gas turbine according to the present invention is divided in the middle in the longitudinal direction and the housing of the RDS intermediate bearing is sandwiched by the divided portions. Therefore, a large vibration resistance rigidity can be obtained, and the RDS vibration can be effectively suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an arrangement of intermediate bearings using a fan frame strut of a gas turbine of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the present invention.
FIG. 3 is a schematic view of an aircraft gas turbine engine.
4A is a cross-sectional view taken along the compressor portion of FIG. 3, and FIG. 4B is a cross-sectional view of a strut.
FIG. 5 is a cross-sectional view showing an arrangement of RDS intermediate bearings.
FIG. 6 is a cross-sectional view showing another arrangement example of the intermediate bearing of the RDS.
FIG. 7 is an explanatory view showing an RDS assembling method.
[Explanation of symbols]
1 Fan casing 2 Core 12 Fan frame 24 Intermediate bearing 30 Fan frame strut 30c Bearing housing

Claims (1)

A vertical shaft support structure for driving a gas turbine accessory gearbox , and among the plurality of fan frame struts that support the gas turbine core from the fan casing, the fan frame strut through which the vertical shaft passes is a longitudinal axis. It is divided in the middle of the direction, and the divided part is assembled by sandwiching an intermediate bearing housing that suppresses the vibration of the vertical axis, and the vertical axis is an umbrella attached to the drive shaft of the high-pressure compressor It has a male spline that fits into the female spline of the gear, and the outer ring and roller of the intermediate bearing are attached in the intermediate bearing housing, and the inner ring of the intermediate bearing is attached to the vertical shaft with a squeeze Then, move the vertical shaft inward so that the male spline at the tip of the vertical shaft Support structure over La internally passes through the vertical axis of the gas turbine, characterized in that the inner ring of the intermediate bearing when fitted into the female splines of the bevel gear is adapted to fit within the middle bearing rollers.

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