GAS TURBINE ENGINE HAVING AN ACCESSORY GEARBOX

Abstract

A gas turbine engine has an accessory gearbox disposed outside of a bypass channel and connected to a housing part, which radially delimits the bypass channel, in a connection region near the housing part and in a connection region far from the housing part. A connecting element is provided between the housing part and the connection region far from the housing part. A longitudinal axis of the connecting element includes an angle in the range of 75° to 115° with a vertical axis of the accessory gearbox.The connecting element can vary a distance between the far connection region and a connection point of the connecting element on the housing part such that deformation of the housing part and a resulting position change of the connection point cause a lesser deflection of the accessory gearbox than a deflection with an unchanged length of the connecting element.

Claims

1. A gas turbine engine having an accessory gearbox, which accessory gearbox is arranged outside of a bypass channel, wherein the accessory gearbox is connected to a casing part, which radially delimits the bypass channel, in a connection region near the casing part and in a connection region remote from the casing part, wherein a connecting element is provided between the casing part and the remote connection region of the accessory gearbox, and wherein a longitudinal axis of the connecting element includes an angle fat in the range of 75° to 115°, preferably of 75° to 105°, with a vertical axis of the accessory gearbox, and in that the connecting element is designed to vary a distance between the remote connection region of the accessory gearbox and an attachment point of the connecting element on the casing part in such a way that a deformation of the casing part and a resulting position change of the attachment point cause a deflection of the accessory gearbox which is in each case less than a deflection of the accessory gearbox in the case of an unchanged length of the connecting element.

2. The gas turbine engine as claimed in claim 1, wherein the angle between the longitudinal axis of the connecting element and the vertical axis of the accessory gearbox has values in the range of 85° to 95°.

3. The gas turbine engine as claimed in claim 1, wherein the angle between the longitudinal axis of the connecting element and the vertical axis of the accessory gearbox is substantially equal to 90°.

4. The gas turbine engine as claimed in claim 1, wherein a further connecting element is provided between the casing part and the connecting element, the first end of which further connecting element is near the casing part and is connected to the casing part and the second end of which is remote from the casing part, wherein the attachment point of the connecting element on the casing part is provided in the region of the second end of the further connecting element.

5. The gas turbine engine as claimed in claim 4, wherein the further connecting element is operatively connected in a fixed manner by its first end to the casing part and in an articulated manner by its second end to the connecting element.

6. The gas turbine engine as claimed in claim 1, wherein the connecting element is connected in an articulated manner to the accessory gearbox.

7. The gas turbine engine as claimed in claim 4, wherein the connecting element is embodied with a component elasticity between the attachment point on the further connecting element and the connection region with the accessory gearbox, with the result that the change in the length of the connecting element between the attachment point on the casing part and the accessory gearbox occurs as a function of a deformation of the casing part and a resulting displacement of the attachment point.

8. The gas turbine engine as claimed in claim 1, wherein, at least in some region or regions, the connecting element is embodied with a component elasticity such that the length of the connecting element between the attachment point on the casing part and the accessory gearbox changes in the event of a deformation of the casing part and a resulting displacement of the attachment point.

9. The gas turbine engine as claimed in claim 1, wherein the connecting element comprises at least two interconnected partial elements, which are arranged at an angle to one another, wherein the one partial element is connected at one end, at the attachment point, to the casing part and at the other end, by a first end, to the other partial element, and wherein the other partial element is operatively connected by its second end to the accessory gearbox.

10. The gas turbine engine as claimed in claim 4, wherein, starting from the first end, a cross section of the further connecting element decreases continuously in the direction of the second end.

11. The gas turbine engine as claimed in claim 1, wherein the connecting element is operatively connected in an articulated manner via spherical bearings to the accessory gearbox and to the casing part.

12. The gas turbine engine as claimed in claim 1, wherein the casing part is a region of an intermediate casing which delimits the bypass channel radially inwardly or radially outwardly, wherein the accessory gearbox is operatively connected to the casing part in each case on the side of the casing part which facehows away from the bypass channel.

Description

[0036] In the figures:

[0037] FIG. 1 shows a simplified longitudinal sectional view of a gas turbine engine having two accessory gearboxes;

[0038] FIG. 2 shows a schematic illustration of a region II which is identified more specifically in FIG. 1 and which comprises one of the accessory gearboxes;

[0039] FIG. 3 shows an illustration of region II corresponding to FIG. 2, wherein the accessory gearbox is shown in different positions;

[0040] FIG. 4 shows the accessory gearbox from a view IV identified more specifically in FIG. 3;

[0041] FIG. 5 shows an illustration, corresponding to FIG. 3, of a further embodiment of the gas turbine engine;

[0042] FIG. 6 shows an illustration, corresponding to FIG. 5, of a further exemplary embodiment of the gas turbine engine with a deflected accessory gearbox;

[0043] FIG. 7 shows a further embodiment of a connecting element of the gas turbine engine, which is arranged between the accessory gearbox and a casing part of the gas turbine engine;

[0044] FIG. 8 shows a further embodiment of the connecting element, which is formed with an elastic element; and

[0045] FIG. 9 shows a further embodiment of the connecting element, which comprises partial elements arranged at an angle to one another.

[0046] FIG. 1 shows a gas turbine engine 1 of an aircraft in a simplified longitudinal sectional view. The gas turbine engine 1 comprises a subsidiary flow channel or bypass channel 2 and an inlet region 3. Downstream of the inlet region 3, a fan 4 is connected in a manner which is known per se.

[0047] After the fan 4, the fluid flow in the gas turbine engine 1 is divided into a bypass flow and a core flow. The bypass flow flows through the bypass channel 2, whereas the core flow flows into an engine core 5. The engine core 5 is embodied with a compressor device 6, with a burner 7, with a low-pressure turbine 8 which is provided to drive the fan 4, and with a high-pressure turbine 9 provided to drive the compressor device 6.

[0048] In addition, FIG. 1 shows a schematically illustrated accessory gearbox 10 which is arranged substantially in the region of an intermediate casing 11 of the gas turbine engine 1. In the manner illustrated in more detail in FIG. 2, the intermediate casing 11 is located between a fan casing 12 and a bypass channel casing 13, which adjoins the intermediate casing 11, in the axial direction A of the gas turbine engine 1. The accessory gearbox 10 is arranged in the intermediate casing 11 between the bypass channel 2 and the engine core 5, i.e. radially inside the bypass channel 2.

[0049] Furthermore, a further accessory gearbox 14 is provided radially outside the bypass channel 2 and is positioned on the side of the intermediate casing 11 which faces away from the engine core 5. The further accessory gearbox 14 is arranged between a radially outer boundary 15 of the bypass channel 2 and within an engine nacelle 16.

[0050] The accessory gearbox 10 is driven by a radial shaft 17, which is operatively connected to a core shaft 18 extending in the axial direction A of the gas turbine engine 1. The further accessory gearbox 14 is driven by a further radial shaft 19, which is likewise operatively connected to the core shaft 18.

[0051] In the present case, the core shaft 18 is a low-pressure shaft of the gas turbine engine 1 which, in the operation of the gas turbine engine 1, rotates at a lower speed than another core shaft 20, which is arranged coaxially therewith and is what is known as a high-pressure shaft.

[0052] Depending on the respective application, there is the possibility that the gas turbine engine 1 is designed only with the accessory gearbox 10 or only with the further accessory gearbox 14.

[0053] FIG. 2 shows the region II, which is identified more specifically in FIG. 1, in which the further accessory gearbox 14 is arranged. The further accessory gearbox 14 is connected in a connection region 21 to a casing part 22 of the intermediate casing 11. In this case, the connection region 21 faces the casing part 22. In addition, the further accessory gearbox 14 is operatively connected to the casing part 22 in a further connection region 23 via a connecting element 24, wherein the casing part 22 forms part of the outer boundary 15 of the bypass channel 2.

[0054] In the region of a first end 25, the connecting element 24 is connected in the further connection region 23 to a casing 26 of the further accessory gearbox 14. In addition, the connecting element 24 is connected in the region of a second end 27 to an attachment point 28 of the casing part 22.

[0055] FIG. 3 shows an illustration corresponding to FIG. 2 of region II of the gas turbine engine 1. FIG. 3 shows the fan casing 12, the intermediate casing 11, the further accessory gearbox 14 and the connecting element 24 in the positions of rest which are shown in FIG. 2 and which these components have in the load-free state.

[0056] In addition, the fan casing 12, the intermediate casing 11, the further accessory gearbox 14 and the connecting element 24 are shown in positions that deviate from the rest positions in each case. The fan casing 12 has the profile identified more specifically by reference sign 12A when, for example, a blade break occurs in the region of the fan 4 and one of the fan blades flies outward at high speed in the radial direction R within the fan casing 12 and strikes the inner side of the fan casing 12.

[0057] As a result of the impact of the free fan blade part, the fan casing 12 is first of all deformed radially outward. Since the intermediate casing 11 is connected to the fan casing 12 via a flange (not shown specifically), the deformation of the fan casing 12 is transmitted to the intermediate casing 11. This has the effect that the attachment point 28 is deflected radially outward from its rest position into the position indicated more specifically by reference sign 28A. In the presence of a rigid connection between the attachment point 28 and the connection region 23, the casing 26 of the further accessory gearbox 14 is pivoted about the connection region 21 from the position of rest of the accessory gearbox 14 into the position shown indicated by reference sign 14A. The deflection of the further accessory gearbox 14 from its position of rest or rest position is identified more specifically in FIG. 3 by reference sign A1.

[0058] The fan casing 12 is deformed in an undulating fashion by the impact of the free blade part, with the result that the fan casing 12 undergoes an oscillating deformation. This means that the fan casing 12 not only oscillates radially outward but also, after the initial radially outward deformation, radially inward again. This deformation of the fan casing 12 is shown by the profile of the fan casing 12 indicated more specifically by reference sign 12B.

[0059] The radially inwardly directed deformation of the fan casing 12 has the effect that, starting from the position indicated by reference sign 28A, the attachment point 28 is deflected radially inward and beyond the rest position 28 into the position indicated by reference sign 28B. The further accessory gearbox 14 is thereby transferred by the connecting element 24 into the pivoted position indicated more specifically by reference sign 14B. In this case, the deflection which the accessory gearbox 14 undergoes in relation to the rest position indicated by reference sign 14 is identified in FIG. 3 by reference sign A2.

[0060] FIG. 4 shows the accessory gearbox 14 from a view IV identified more specifically in FIG. 3. It is apparent from the illustration according to FIG. 4 that the connection region 21 comprises two lateral attachment points 29 and 30, which are spaced apart from one another in the circumferential direction U of the gas turbine engine 1. In the region of the attachment points 28, 29 and 30, spherical bearings are provided in each case, comprising bolts or the like mounted in rubber bearings.

[0061] Furthermore, it is apparent from the illustration according to FIG. 4 that the casing 26 of the further accessory gearbox 14 is bent or deformed in the axial direction A between the attachment points 29 and 30 owing to the deformation of the fan casing 12 and the attachment to the casing part 22 in the region of the two further attachment points 29 and 30. The deformations of the casing 26 are each identified more specifically by reference signs 26A and 26B.

[0062] In order to minimize or limit the deflections A1 and A2 of the further accessory gearbox 14 which are indicated in FIG. 3, the further accessory gearbox 14 is attached to the casing part 22 of the intermediate casing 11 to the extent illustrated in FIG. 5. In the exemplary embodiment of the gas turbine engine 1 shown in FIG. 5, the connecting element 24 is operatively connected to the casing part 22 via a further connecting element 31. The further connecting element 31 is rigidly connected to the casing part 22 and projects outward from the casing part 22 in the radial direction R.

[0063] In the present case, the attachment point 28 for the connecting element 24 on the casing part 22 is provided in the region of the free end 32 of the further connecting element 31. In the present case, a radial distance between the attachment point 28 and the casing part 22 is designed in such a way that a longitudinal axis 33 of the connecting element 24 includes an angle α of approximately 90° with a vertical axis 34 of the further accessory gearbox 14 and with a longitudinal axis 35 of the further connecting element 31 in the position of rest of the casing part 22 and of the further accessory gearbox 14. In this case, the vertical axis 34 of the further accessory gearbox 14 and the longitudinal axis 35 of the further connecting element 31 run substantially in the radial direction R in the position of rest of the gas turbine engine 1 shown in FIG. 5.

[0064] In addition, the connecting element 24 is connected both to the connection region 23 of the casing 26 of the further accessory gearbox 14 and to the attachment point 28 of the further connecting element 31 or of the casing part 22 in each case in an articulated manner.

[0065] FIG. 6 shows an illustration, corresponding to FIG. 5, of the region II, wherein the fan casing 12 and the further accessory gearbox 14 are shown both in their rest position and in their deflected or deformed operating states 12B and 14B, respectively. It is apparent from the illustration according to FIG. 6 that the “toggle lever attachment” of the further accessory gearbox 14 to the intermediate casing 11 brings about significantly less deflection A1′ of the accessory gearbox 14 relative to its rest position, as compared with the illustration according to FIG. 3, for the same radial deflection of the fan casing 12 and of the intermediate casing 11.

[0066] As an alternative to this or in addition to this, there is also the possibility of embodying the connecting element 24 with a defined component elasticity so that a length of the connecting element 24 is variable. For this purpose, the connecting element 24 can be embodied in the manner illustrated by way of example in FIG. 7 to FIG. 9.

[0067] In the embodiment shown in FIG. 7, the connecting element 24 has what is known as a bone shape. The end 25 adjacent to the connection region 23 and the second end 27 of the connecting element 24, which is adjacent to the attachment point 28, each have a larger cross section than the region between them. This cross-sectional configuration of the connecting element 24 offers the possibility that a corresponding tensile or compressive load on the connecting element 24 brings about a change in the length of the connecting element 24, i.e. an elongation or a compression. For a compressive load, the connecting element 24 is designed in such a way that elastic buckling can occur, as a result of which an axial length of the connecting element 24 is shortened and thus also the distance between the connection region 23 and the attachment point 28. For a tensile load, the connecting element 24 is designed in such a way that the connecting element 24 allows an elastic elongation. The variable length of the connecting element 24 offers the possibility of limiting the deflections A1 and A2 of the further accessory gearbox 14 if the fan casing 12 and the intermediate casing 11 operatively connected thereto are deformed radially outward or inward to the extent described above.

[0068] The embodiment of the connecting element 24 shown in FIG. 8 has two rigid parts 24A and 24B, which are operatively connected to one another via an elastically deformable intermediate element 24C. The function of the elastic intermediate element 24C is to allow elongation or compression of the connecting element 24 in the case of a corresponding compressive or tensile load on the connecting element 24. As a result, the deflections A1 and A2 of the accessory gearbox 14 can be compensated to a certain extent and limited to a minimum in the event of a radial deformation of the fan casing 12.

[0069] In the exemplary embodiment of the connecting element 24 shown in FIG. 9, the connecting element 24 has four partial elements 241 to 244. In this case, the partial elements 241 and 242 and the partial elements 243 and 244 are in each case arranged at an angle to one another and connected to one another. The substantially rhombic arrangement of the partial elements 241 to 244 offers the possibility, in a kinematic way, of increasing or shortening a distance between the connection region 23 and the attachment point 28 to the desired extent when there is a compressive or tensile load on the connecting element 24.

[0070] In addition, however, the pendulum function of the connecting element 24 can also be used in order to allow shortening or lengthening of the distance. For this purpose, as can be seen in FIGS. 2, 3, 5 and 6 and already described above, the connecting element 24 is mounted in an articulated manner at the respective attachment points, thus enabling rotation about the respective attachment points. In the event of a radial displacement of the fan casing 12 or of the intermediate casing 11, the accessory gearbox can oscillate, with the result that the displacements of the fan casing 12 and/or of the intermediate casing 11 are not completely transmitted to the accessory gearbox 14, resulting in a smaller displacement of the accessory gearbox 14.

[0071] During the oscillation of the accessory gearbox 14, the length of the connecting element 24 can change. Such a change in length usually occurs in the case of large angular changes. This change in length is compensated by the elastic or kinematic design of the connecting element in accordance with the embodiments of FIGS. 7 or 8 or 9, with the result that a distance between the remote connection region 23 of the accessory gearbox 14 and an attachment point 28 of the connecting element 24 on the casing part 22 varies in such a way that a deformation of the casing part 22 and a resulting change in position of the attachment point 28 causes a deflection of the accessory gearbox 14 which is in each case less than a deflection of the accessory gearbox 14 in the case of an unchanged, i.e. rigid, length of the connecting element.

[0072] The accessory gearbox 10 is attached to the intermediate casing 11 substantially in the same way as the further accessory gearbox 14, for which reason an explicit description is dispensed with and reference is made to the above description in respect of the structural design and mode of operation regarding the attachment of the further accessory gearbox 14 to the intermediate casing 11.

[0073] At this point, it is also pointed out that the deflections of the accessory gearboxes 10 and 14 can also be limited in dependence on the design of the distances between the attachment points 29, 30 of connection region 21 and connection region 23. The exemplary embodiments described in more detail above can each be integrated into existing engine systems with little design effort in order to limit loads in the region of accessory gearboxes.

TABLE-US-00001 List of reference signs 1 Gas turbine engine 2 Bypass channel 3 Inlet region 4 Fan 5 Engine core 6 Compressor device 7 Burner 8 Low-pressure turbine 9 High-pressure turbine 10 Accessory gearbox 11, 11A, 11B Intermediate casing 12, 12A, 12B Fan casing 13 Bypass channel casing 14, 14A, 14B Further accessory gearbox 15 Outer boundary of the bypass channel 16 Engine nacelle 17 Radial shaft 18 Core shaft 19 Further radial shaft 20 Further core shaft 21 Connection region 22, 22A, 22B Casing part 23 Further connection region 24 Connecting element 24A, 24B Partial element 24C Intermediate element 25 End of connecting element 24 26 Casing of the further accessory gearbox 27 Second end of connecting element 24 28, 28A, 28B Attachment point of connecting element 24 on casing part 22 29, 30 Attachment points 31 Further connecting element 32 Second end of further connecting element 31 33 Longitudinal axis of connecting element 24 34 Vertical axis of the further accessory gearbox 35 Longitudinal axis of further connecting element 31 241 to 244 Partial element of connecting element 24 A Axial direction R Radial direction U Circumferential direction A1, A2, A1′ Deflection of the further accessory gearbox α Angle