Air turbine starter with fluid damping assembly

Abstract

An air turbine starter for starting an engine has a housing defining an inlet, an outlet, and an airflow path extending between the inlet and the outlet. The housing includes a seal defining at least a portion of an airflow path. A drive shaft rotatably coupled to the turbine defines an axis of rotation. The turbine includes circumferentially spaced blades disposed at least partially within the airflow path. The at least one bearing rotatably supports the drive shaft. A bearing support structure is positioned between the at least one bearing and the seal. The fluid damping assembly includes one or more conduits fluidly coupling a fluid source to a fluid reservoir.

Description

Technical Field

[0001] The present subject matter relates generally to an air turbine starter and, more particularly, to a fluid damping assembly in an air turbine starter. Background Art

[0002] Aircraft engines (e.g., gas turbine engines) typically include an air turbine starter for starting the gas turbine engine. The internal components of the air turbine starter require bearings. In the air turbine starter, the bearings transmit radial and axial loads during rotor operation. The air turbine starter bearings are typically sized and designed based on load inputs from rotor dynamics and axial thrust. During operation, the air turbine starter bearings are typically subject to high radial loads caused by rigid mounting. Summary of the invention

[0003] Technical Solution 1. An air turbine starter for starting an engine, comprising:

[0004] a housing having an inlet, an outlet, and an air flow path extending between the inlet and the outlet, wherein the housing includes a seal defining at least a portion of the air flow path;

[0005] a drive shaft rotatably coupled to the turbine, defining an axis of rotation and having circumferentially spaced blades disposed at least partially within the air flow path;

[0006] a bearing rotatably supporting the drive shaft;

[0007] a bearing support structure positioned at least partially between the bearing and the seal; and

[0008] A fluid damping assembly includes one or more conduits fluidly coupling a fluid source to a fluid reservoir, wherein the fluid reservoir includes a fluid cavity defined at least in part by portions of the bearing support structure.

[0009] Technical Solution 2. An air turbine starter according to Technical Solution 1, wherein the fluid damping assembly further comprises a flow regulating device, the flow regulating device being connected to the one or more ducts or positioned within the one or more ducts.

[0010] Technical Solution 3. An air turbine starter according to Technical Solution 2, wherein the flow regulating device is a valve connected to a controller or a power source.

[0011] Technical Solution 4. An air turbine starter according to Technical Solution 2, wherein the flow regulating device is radially positioned between the fluid source and the fluid reservoir.

[0012] Technical Solution 5. An air turbine starter according to Technical Solution 2, wherein the flow regulating device provides pressurized fluid to the fluid reservoir.

[0013] Technical Solution 6. An air turbine starter according to any one of Technical Solutions 1-5, wherein the fluid source provides pressurized fluid to the fluid reservoir.

[0014] Technical Solution 7. An air turbine starter according to Technical Solution 6, wherein the pressurized fluid is pressurized oil.

[0015] Technical Solution 8. An air turbine starter according to any one of Technical Solutions 1-5, wherein the fluid chamber is defined by the portion of the bearing support structure, the portion of the seal, and the side wall.

[0016] Technical Solution 9. An air turbine starter according to Technical Solution 8, wherein the side wall is press-fitted between the bearing support structure and the portion of the seal.

[0017] Technical Solution 10. The air turbine starter according to Technical Solution 8 further includes an auxiliary fluid reservoir, which is fluidly connected to the fluid source and the fluid reservoir and is radially positioned between the fluid source and the fluid reservoir.

[0018] Technical Solution 11. An air turbine starter according to Technical Solution 10, wherein the auxiliary fluid reservoir is a group of auxiliary fluid reservoirs radially positioned between the fluid source and the fluid reservoir, wherein each reservoir in the group of auxiliary fluid reservoirs is radially spaced apart from another reservoir in the group of auxiliary fluid reservoirs.

[0019] Technical Solution 12. An air turbine starter according to any one of Technical Solutions 1-5, wherein the bearing is a first bearing, the air turbine starting device includes a second bearing, and the bearing support structure includes a first bearing support adjacent to the first bearing and a second bearing support adjacent to the second bearing.

[0020] Technical Solution 13. An air turbine starter according to Technical Solution 12, wherein the bearing support structure includes a spring finger structure defined by the first bearing support, the second bearing support and at least one flexible connector.

[0021] Technical Solution 14. An air turbine starter according to Technical Solution 13, wherein the spring is axially positioned between one of the at least one flexible connector and the second bearing.

[0022] Technical Solution 15. An air turbine starter according to Technical Solution 13, wherein the fluid reservoir of the fluid damping assembly is a first fluid reservoir, and the fluid damping assembly includes a second fluid reservoir, wherein the first fluid reservoir is positioned between the first bearing support and the seal, and the second fluid reservoir is axially spaced apart from the first fluid reservoir and positioned between the second bearing support and the portion of the second bearing.

[0023] Technical Solution 16. The air turbine starter according to Technical Solution 15 further includes a first valve and a second valve, wherein the first valve is positioned between the fluid source and the first fluid reservoir, and the second valve is positioned between the fluid source and the second fluid reservoir.

[0024] Technical Solution 17. The air turbine starter according to Technical Solution 16 also includes one or more of a pump, a flow sensor, a pressure sensor, a valve, a filter or a discharge line.

[0025] Technical Solution 18. An air turbine starter according to any one of Technical Solutions 1-5, wherein the fluid chamber is defined by the portion of the bearing support structure, the portion of the bearing, and the side wall.

[0026] Technical Solution 19. An air turbine starter according to Technical Solution 18, wherein the side wall is press-fitted between the portion of the bearing support structure and the portion of the bearing.

[0027] Technical Solution 20. The air turbine starter according to Technical Solution 18 further includes an auxiliary fluid reservoir, which is fluidly connected to the valve positioned in the one or more conduits and the fluid reservoir and is radially positioned between the valve and the fluid reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the attached picture:

[0029] Figure 1 is a schematic illustration of a gas turbine engine with an air turbine starter in accordance with various aspects described herein.

[0030] Figure 2 A bearing support structure according to an exemplary embodiment of the present disclosure Figure 1 Cross-sectional view of an air turbine starter.

[0031] Figure 3 is a spring finger structure from an exemplary embodiment of the present disclosure Figure 2 An enlarged cross-sectional view of the bearing support structure.

[0032] Figure 4 According to an exemplary embodiment of the present disclosure Figure 3 Variations of the bearing support structure. DETAILED DESCRIPTION

[0033] The present disclosure relates to an air turbine starter ("ATS"), and more particularly to a bearing support structure for the ATS. The ATS includes a turbine shaft supported by a turbine bearing mounted on a turbine exhaust housing. The bearing support structure disclosed herein enables flexibility, thereby obtaining lower bearing loads, thereby extending the life of the bearings and the bearing support structure. The flexibility provided by the bearing support structure disclosed herein can provide structural flexibility to absorb radial loads, axial loads, or both radial and axial loads. The ATS can have various applications, including starting a gas turbine engine and generating electrical power while the gas turbine engine is in operation. Although the exemplary embodiments described herein are directed to a bearing support structure for an ATS, embodiments of the present disclosure can be applied to any implementation of a support bearing for an engine component.

[0034] A typical ATS has a conventional turbine bearing with a bearing sleeve mounted to the turbine housing via an interference fit to support the turbine rotor. The turbine bearing transfers radial and axial loads from the turbine rotor during operation. The bearing is sized and designed to accommodate the rotor dynamic forces and axial thrust loads generated during operation. Due to the rigid mounting, the bearing experiences high radial loads in critical mode, which in turn affects the life of the bearing.

[0035] In order to improve bearing life, a soft-mounted bearing arrangement incorporating flexibility in the bearing load path is described herein. The soft-mounted bearing arrangement generates lower radial loads by shifting the critical mode of the rotor to a lower speed or revolutions per minute (RPM). The soft-mounted bearing arrangement described in more detail herein is able to achieve flexibility in the bearing load path by implementing a flexible connector and utilizing a low stiffness structure between the bearings. When the axial load does not change, the flexible connector provides a transition from a natural frequency or critical mode to a portion of the operating range that is quickly passed. That is, the flexible connector provides a transition away from a "dwelling range" of the natural frequency or critical mode, where the term "dwelling range" refers to a speed or speed range at which the ATS can stay or remain during operation. In other words, the natural frequency or critical mode is shifted to an operating speed that the ATS passes quickly, thereby reducing the number of high reaction load cycles on the bearing. It is envisioned that a flexible connector can provide a transition of at least a portion of the natural frequency, critical mode, or harmonics of the natural frequency that exceeds the current operating range.

[0036] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, unless expressly identified otherwise, all embodiments described herein should be considered exemplary.

[0037] As used herein, terms such as “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of an individual component.

[0038] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, with respect to a gas turbine engine, the front refers to a position closer to the engine inlet and the rear refers to a position closer to the engine nozzle or exhaust.

[0039] As used herein, the term "upstream" refers to a direction opposite to the direction of fluid flow, and the term "downstream" refers to a direction in the same direction as the fluid flow. The terms "front" or "in front" mean in front of something, and "rear" or "rearward" mean behind something. For example, when used in relation to fluid flow, front / front may mean upstream, and rear / rearward may mean downstream.

[0040] Furthermore, as used herein, the terms "radial" or "radially" refer to directions extending toward or away from a common center. For example, in the general context of turbine engines, radial refers to directions along a ray extending between a central longitudinal axis of the turbine engine and the periphery of the engine. Furthermore, as used herein, the terms "group" of elements or "grouping" of elements may be any number of elements, including only one.

[0041] All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, front, rear, etc.) are used only for identification purposes to help the reader understand the present disclosure and do not create limitations, particularly limitations on the position, orientation, or use of the disclosure described herein. Connection references (e.g., attachment, connection, connection, and connection) should be interpreted broadly and may include intermediate structural elements between a series of elements and relative movement between elements unless otherwise indicated. Therefore, a connection reference does not necessarily mean that two elements are directly connected and are in a fixed relationship to each other. The exemplary drawings are for illustrative purposes only, and the dimensions, positions, orders, and relative sizes reflected in the attached drawings may vary.

[0042] refer to Figure 1, an air turbine starter motor or air turbine starter (ATS) 10 is coupled to an accessory gearbox (AGB) 12 (also referred to as a transmission housing), and together are schematically illustrated as being mounted to a turbine engine 14, such as a gas turbine engine. The turbine engine 14 includes an air intake having a fan 16, which supplies air to a compression region having a high-pressure compression region 18. The fan 16 may define an axis of rotation 17 of the engine. The air intake having the fan 16 and the compression region are collectively referred to as the "cold section" of the turbine engine 14. The cold section is located upstream of the combustion section of the turbine engine 14. The high-pressure compression region 18 provides high-pressure air to a combustion chamber 20 of the combustion section. In the combustion chamber 20, the high-pressure air is mixed with fuel and combusted. The hot and pressurized burned gases pass through a turbine region illustrated as having a high-pressure turbine region 22 and a low-pressure turbine region 24 before being discharged from the turbine engine 14. When the pressurized gas passes through the high-pressure turbine (not shown) of the high-pressure turbine area 22 and the low-pressure turbine (not shown) of the low-pressure turbine area 24, the turbine extracts kinetic energy from the gas flow passing through the turbine engine 14. The high-pressure turbine of the high-pressure turbine area 22 can be coupled to the compression mechanism (not shown) of the high-pressure compression area 18 by a shaft to provide power to the compression mechanism. The low-pressure turbine can be coupled to the fan 16 of the air intake by a shaft to provide power to the fan 16.

[0043] The AGB 12 may be coupled to the turbine engine 14 at one or more of the high or low pressure compressor or turbine sections 18, 22, 24. The coupling of the AGB 12 to the turbine engine 14 may be achieved through a mechanical power takeoff 26. The mechanical power takeoff 26 includes a plurality of gears and means for mechanically coupling the AGB 12 to the turbine engine 14. The mechanical power takeoff 26 may transfer power from the turbine engine 14 to the AGB 12 to provide power to accessories of the aircraft, such as, but not limited to, fuel pumps, electrical systems, and cabin environmental controls.

[0044] The ATS 10 may be positioned radially outward of the fan case 28. That is, the ATS 10 may be positioned radially outward of the air inlet region containing the fan 16. Alternatively, it is contemplated that the ATS 10 may be positioned outboard of the core near the high pressure compression region 18, in a different and non-limiting example, wherein the ATS 10 may be coupled to a transmission gearbox (not shown) or an accessory gearbox (not shown). Furthermore, any positioning of the ATS 10 is contemplated where the ATS 10 may be coupled to the turbine engine 14.

[0045] Figure 2 For example, it can be included in Figure 1Schematic cross-section of an exemplary ATS10 in FIG. The ATS10 includes a housing 30 that defines an interior 31 and an exterior 32 of the housing 30. An inlet 34 and an outlet 36 are also defined by the housing 30. An air flow path 38 through the interior 31 is schematically illustrated by arrows. The air flow path 38 extends between the inlet 34 and the outlet 36 for transmitting a fluid flow therethrough, the fluid flow including but not limited to gas, compressed air, etc. In a non-limiting example, the fluid is air, such as pressurized air supplied from a compressed air source, the compressed air source including but not limited to a ground-operated air vehicle, an auxiliary power unit, or a cross-drain starting device from an already running engine. The housing 30 can be formed in any suitable manner, including but not limited to, it can be made of two or more components that are linked or otherwise connected together, or can be integrally formed as a single piece.

[0046] like Figure 2 As shown in , the seal 40 is coupled to the housing 30 or formed integrally with the housing 30. It is contemplated that the seal 40 can divide the interior 31 into a dry portion and a wet portion. In the illustrated example, at least a portion of the seal 40 defines at least a portion of the air flow path 38. It is further contemplated that the seal 40 can be a plurality of portions coupled together to define one or more portions of the interior 31.

[0047] While illustrated as a seal 40 separating a “wet” portion of the ATS 10 from a “dry” portion of the housing, it is contemplated that the seal 40 need not necessarily perform as a seal and may be any portion of the housing 30 or structure coupled to the housing 30 .

[0048] Turbine 42 is positioned within interior 31 of housing 30. At least a portion of turbine 42 is disposed within air flow path 38 for rotatably extracting mechanical power from the gas flow along air flow path 38. Turbine 42 includes a rotor portion 44 and a plurality of circumferentially spaced blades 46.

[0049] The drive shaft 50 is coupled to the rotating turbine 42 so that the drive shaft 50 can provide a rotational output. An output gear assembly 52 coupled to the drive shaft 50 allows mechanical power to be transferred from the turbine 42 to the output gear assembly 52 via the rotational output of the drive shaft 50. Portions of the turbine 42, the drive shaft 50, and / or the output gear assembly 52 can rotate about an axis of rotation 54.

[0050] The output gear assembly 52 may include a gear train 56. A carrier member 58 may be drivingly coupled with the gear train 56. The driven member 60 may include a shaft 62 and may be rotatably mounted to the carrier member 58. The carrier member 58 may be supported by a carrier bearing 64.

[0051] The clutch 66 may be mounted to the carrier member 58. The driven member 60 is coupled to the clutch 66 and is additionally supported by the drive bearing 68. The driven member 60 is driven by the carrier member 58, which in turn is driven by the gear train 56, which in turn is driven by the turbine 42.

[0052] The decoupler assembly 70 may be disposed within at least a portion of the driven component 60. An output shaft 72 may be mounted to the shaft 62. The output shaft 72 may be operably coupled to the turbine engine 14 ( Figure 1 ), so that the output shaft 72 can rotate a portion of the turbine engine 14. It is contemplated that the output shaft 72 can be operably coupled to one or more portions of the compression region or the turbine region. In other words, the output shaft 72 can rotate one or more portions of the compression region or the turbine region.

[0053] The bearing assembly 80 rotatably supports the drive shaft 50, and therefore also the turbine 42. The bearing assembly 80 includes at least one bearing, illustrated as a first bearing 82 and a second bearing 84, a bearing support structure 86, and a fluid damping assembly 90. By way of example, the bearing support structure 86 is at least partially positioned radially between the seal 40 and the drive shaft 50. Although illustrated as being axially forward of the output gear assembly 52, the bearing assembly 80 may be positioned axially rearward of the output gear assembly 52.

[0054] The bearing assembly 80 may be positioned anywhere in the ATS 10. In various and non-limiting examples, it is contemplated that the carrier bearing 64 or the drive bearing 68 is part of one or more bearing assemblies similar to the bearing assembly 80 having at least one bearing, a bearing support structure, and a fluid damping assembly.

[0055] Figure 3 Is from Figure 2 FIG. 8 is an enlarged cross-sectional view of section III of FIG. 8 , which illustrates a bearing assembly 80. The first bearing 82 and the second bearing 84 may be ball bearings as shown or any type of bearings, including cylindrical roller bearings, tapered roller bearings, and needle bearings. The first bearing 82 and the second bearing 84 may operate as parallel bearings. The first bearing 82 may be a thrust bearing or a main load bearing, while the second bearing 84 may be a preloaded bearing capable of maintaining the ball angle load angle of the first bearing 82.

[0056] The bearing support structure 86 is a flexible bearing support structure that includes one or more flexible portions that absorb or dampen relative movement between the seal 40 or housing 30 and the first bearing 82 or the second bearing 84. That is, one or more portions of the bearing support structure 86 can dissipate energy and / or transmit loads. It is contemplated that the bearing support structure 86 can act like a shock absorber.

[0057] By way of example, the bearing support structure 86 is illustrated as including a spring finger structure 92 disposed between the seal 40 or the housing 30 and one or more of the first bearing 82 or the second bearing 84. More particularly, the spring finger structure 92 is positioned between portions of the seal 40 and a first outer race 94 of the first bearing 82 and a second outer race 96 of the second bearing 84.

[0058] The spring finger structure 92 extends axially between a first end 98 and a second end 100. The spring finger structure 92 includes a first bearing support 104 that receives or supports a portion of the first bearing 82 and a second bearing support 106 that receives or supports a portion of the second bearing 84.

[0059] The spring finger structure 92 may include at least one flexible connector 108 for connecting the first bearing support 104 to the second bearing support 106. The spring finger structure 92 may be mounted to the seal 40 using any suitable fastener 110, such as, but not limited to, a bolt. The at least one flexible connector 108 may be formed of a shape memory alloy (denoted as "SMA") material. It is further contemplated that the entire spring finger structure 92 is formed of an SMA material.

[0060] A spring 112 or other known spacer or damping element may be disposed between the first bearing 82 and the second bearing 84. As illustrated, by way of example, the spring 112 may extend between one of the flexible connectors 108 and the second outer race 96 of the second bearing 84. The spring 112 and at least one flexible connector 108 facilitate flexible movement of the spring finger structure 92. The spring 112 may absorb or reduce axial loads on the second bearing 84 by preloading at least the second outer race 96 of the second bearing 84.

[0061] The first inner race 95 of the first bearing 82 and the second inner race 97 of the second bearing 84 rotatably support the drive shaft 50. The first bearing 82 and the second bearing 84 may be axially spaced relative to the rotation axis 54. The spring finger structure 92 may include a first bearing support 104 and a second bearing support 106 for accommodating the first bearing 82 and the second bearing 84, respectively.

[0062] The first bearing support 104 and the second bearing support 106 of the spring finger structure 92 can be formed to have two different axial / thrust (AT) load capacities. The first bearing support 104 (and optional surrounding structure) can be formed to have a first AT value (AT1), while the second bearing support 106 (and optional surrounding structure) can be formed to have a second AT value (AT2) that is, for example, less than AT1. In other words, the first bearing support 104 is more flexible in the axial direction than the second bearing support 106 because the first bearing support 104 has an AT value that is greater than the AT value of the second bearing support 106.

[0063] Likewise, the first bearing support 104 and the second bearing support 106 of the spring finger structure 92 can be formed to have two different radial load / stiffness (K) capabilities. Stiffness (K) can be determined as the force applied to stretch, compress, or deflect an object divided by the distance the object is lengthened, shortened, or deflected. For example, object A having a lower K value than object B indicates that object A is easier to stretch / compress or less rigid than object B.

[0064] The first bearing support 104 (and optional surrounding structure) can be formed to have a first K value (K1), while the second bearing support 106 (and optional surrounding structure) can be formed to have a second K value (K2), for example, a value greater than K1. In other words, the first bearing support 104 can have a higher AT and a lower K than the second bearing support 106. Therefore, the spring finger structure 92 can define a dual differentially rated thrust bearing system, wherein the second bearing 84 can be an "axial bearing" that is movable or more easily flexed in the axial direction (Ad), and the first bearing 82 can be a "radial bearing" that is movable or more easily flexed in the radial direction (Rd). It is also contemplated that the first bearing 82 is an axial bearing and the second bearing 84 is a radial bearing. In other words, the dual differentially rated thrust bearing system has one bearing that is axially harder and radially softer, while the other bearing is axially softer and radially harder.

[0065] To reduce radial loads on first bearing 82, first bearing support 104 has a low K value and is spaced a distance 114 from seal 40. Fluid damping assembly 90 further reduces radial loads on first bearing 82. Fluid damping assembly 90 may include a first fluid reservoir 116 and a fluid source 118.

[0066] The first fluid reservoir 116 is positioned between the first bearing support 104 and the seal 40. The first fluid reservoir 116 includes a portion of the first bearing support 104, a portion of the seal 40, and a fluid dam, which is illustrated as a sidewall 120 defining a first fluid cavity 122. The sidewall 120 may be made of a flexible or shape memory material that allows the first bearing support 104 to flex or bend toward the seal 40. The sidewall 120 may capture, seal, bind or otherwise limit or constrain the flow of liquid from the first fluid cavity 122 to the area between the seal 40 and the spring finger structure 92. The sidewall 120 may include a non-absorbent material. Alternatively, in different and non-limiting examples, the sidewall 120 may include a material that absorbs, for example, oil. The first fluid cavity 122 may be a variable volume cavity for dampening radial movement of the first bearing 82. One or more sidewalls 120 may be positioned between the first bearing support 104 and the seal 40 or press fit between the first bearing support 104 and the seal 40. As used herein, the term "press fit" is an interference fit in which the coupling of two components is achieved by normal force, friction, or cold welding. That is, before the sidewall 120 is positioned between the seal 40 and the spring finger structure 92, at least one dimension of the sidewall 120 is greater than the distance 114 between the seal 40 and the spring finger structure 92. It is contemplated that the sidewall 120 can retain the oil volume in the first fluid chamber 122.

[0067] Alternatively, in another non-limiting example, the sidewall 120 may be coupled to the first bearing support 104, the seal 40, or the first bearing support 104 and the seal 40. By way of non-limiting example, the sidewall 120 or the fluid dam may be a piston ring. Alternatively, in another different and non-limiting example, the sidewall 120 may be a series of structures that restrict fluid flow from the first fluid cavity 122 to the area between the first bearing support 104 and the seal 40. By way of non-limiting example, the series of structures may include one or more structures coupled to the first bearing support 104, the seal 40, or the first bearing support 104 and the seal 40.

[0068] The fluid source 118 is fluidly coupled to the first fluid reservoir 116 via one or more first conduits 126. The fluid source 118 may be journaled, contained within the seal 40 or housing 30 ( Figure 2 ) within, defined by, supported by, or otherwise coupled to the seal 40 or housing 30 ( Figure 2 ).

[0069] The flow regulating device, illustrated as a first valve 130, can control the volume or flow rate of the fluid between the fluid source 118 and the first fluid reservoir 116. The flow regulating device, illustrated as a first valve 130, can be coupled to or positioned within one or more first conduits 126. Alternatively, in a different and non-limiting example, the first valve 130 can be positioned at the outlet of the fluid source 118.

[0070] The first valve 130 may be active (actively controlled) or powered. It is contemplated that the first valve 130 may be coupled to a controller and / or power source 132. Alternatively, in a different and non-limiting example, the first valve 130 may be passive, unpowered, and responsive to an internal pressure. The first valve 130 may allow flow from the fluid source 118 to the first fluid reservoir 116, or allow flow from the first fluid reservoir 116 to the fluid source 118. Although illustrated as being radially positioned between the fluid source 118 and the first fluid reservoir 116, any positioning of the first valve 130 is contemplated in which the first valve 130 may control fluid flow between the fluid source 118 and the first fluid reservoir 116.

[0071] When the first bearing support 104 flexes in the radial direction (Rd) toward the seal 40, the distance 114 may decrease by 0% to 100%. More specifically, the distance 114 may decrease by 0% to 50%. More specifically, the distance 114 may decrease by 0% to 20%.

[0072] The spring 112 and the material selected for the second bearing support 106 may absorb or reduce axial loads on the second bearing 84 at least through preloading of the spring finger structure 92 .

[0073] The fluid damping assembly 90 may include a second fluid reservoir 136. The second fluid reservoir 136 may be positioned between the second bearing support 106 and the second bearing 84. Alternatively, in a different and non-limiting example, the second fluid reservoir 136 may be positioned between the second bearing support 106 and the seal 40.

[0074] The second fluid reservoir 136 includes a portion of the second bearing support 106, a portion of the second bearing 84, and a fluid dam, with the flow to the dam being illustrated as a sidewall 140 defining a second fluid cavity 142. The flexibility of the sidewall 140 of the second fluid reservoir 136 may be similar to the sidewall 120 of the first fluid reservoir 116. The sidewall 140 of the second fluid reservoir 136 may be made of a flexible or shape memory material that allows the first bearing support 104 to flex or bend toward the seal 40. In a different and non-limiting example, the flexibility of the sidewall 140 of the second fluid reservoir 136 may be different in the radial direction (Rd) compared to the sidewall 120 of the first fluid reservoir 116. It is further contemplated that the sidewall 140 of the second fluid reservoir 136 may have a different flexibility in the axial direction Ad than the sidewall 120 of the first fluid reservoir 116.

[0075] The sidewalls 140 of the second fluid reservoir 136 may capture, seal, confine, or otherwise limit or restrict the flow of liquid from the second fluid cavity 142 to the area between the second bearing 84 and the spring finger structure 92. One or more of the sidewalls 140 may be positioned or press fit between the second bearing support 106 and the second bearing 84. The second fluid cavity 142 may be a variable volume cavity for dampening radial movement of the second bearing support 106 or the second bearing 84.

[0076] The second bearing distance 144 may be measured between the second outer race 96 of the second bearing 84 to the spring finger structure 92. The second bearing distance 144 may be less than the distance 114 between the first bearing support 104 and the seal 40. The second bearing distance 144 may be between 5% and 50% of the distance 114 between the first bearing support 104 and the seal 40.

[0077] The fluid source 118 may be fluidly coupled to the second fluid reservoir 136 via one or more second conduits 146. Alternatively, in a different and non-limiting example, the second fluid reservoir 136 may be fluidly coupled to another fluid source 148 separate and / or spaced apart from the fluid source 118 via the second conduits 146.

[0078] The second valve 150 can control the volume or flow rate of fluid between the fluid source 118 or another fluid source 148 and the second fluid reservoir 136. The flow regulating device, illustrated as the second valve 150, can be coupled to or positioned within one or more second conduits 146. Alternatively, in a different and non-limiting example, the second valve 150 can be positioned at an outlet of the fluid source 118 or another fluid source 148.

[0079] The second valve 150 may be active or powered. Optionally, it is contemplated that the second valve 150 may be coupled to the controller and / or power source 132. Alternatively, in a different and non-limiting example, the second valve 150 may be passive, unpowered, and responsive to internal pressure. The second valve 150 may allow fluid to flow into or out of the second fluid cavity 142. The second valve 150 may allow fluid to flow into or out of the second fluid cavity 142.

[0080] When the second bearing support 106 flexes in the radial direction (Rd) toward the seal 40, the second bearing distance 144 may decrease by 0% to 100%. More specifically, the second bearing distance 144 may decrease by 0% to 50%. More specifically, the second bearing distance 144 may decrease by 0% to 20%.

[0081] The flexibility of the second fluid reservoir 136 in the radial direction (Rd) can increase the capacity or load-bearing capacity of the second bearing 84. The radial flexibility in the second bearing 84 increases the radial flexibility of the first bearing 82. When the first bearing 82 is allowed to flex radially, the drive shaft 50 can apply a load or "push" into the second bearing 84. Therefore, the increase in the flexibility of the second bearing 84 allows a greater "push" or load to be applied to the second bearing.

[0082] Although compliance increases radial loads on the second bearing 84 , the second fluid reservoir 136 (and optionally the material selected for the second bearing support 106 ) may dampen, dissipate, distribute, transfer, reduce radial reaction forces, or otherwise reduce radial loads on the second bearing 84 .

[0083] By way of example, the second bearing support 106 is illustrated as being in contact with the seal 40 and spaced apart from the second outer race 96 of the second bearing 84. However, in different and non-limiting examples, it is contemplated that a gap may be positioned between the second bearing support 106 and the seal 40, or that the second bearing support 106 may be in contact with at least a portion of the second outer race 96.

[0084] Although illustrated as having a first bearing support and a second bearing support, any number (including one) of bearing supports may be formed by the spring finger structure 92 .

[0085] Optionally, the fluid damping assembly 90 may include one or more flow control elements 166. Although illustrated as being between the first valve 130 and the fluid source 118, it is contemplated that the one or more flow control elements 166 may be fluidly or operably coupled to any portion of the fluid damping assembly 90. The one or more flow control elements 166 may include, but are not limited to, one or more of a pump, a flow sensor, a pressure sensor, an additional valve, a filter, or a bleed line.

[0086] In operation, in the turbine engine 14 ( Figure 1 ) via ATS10( Figure 2 ) during startup, compressed air is supplied to the ATS10( Figure 2 )Entrance 34( Figure 2 ) at the place. The compressed air passes through the seal 40 ( Figure 2 ) is directed through the air flow path 38 ( Figure 2 The turbine 42 in the air flow path 38 ( Figure 2 ) rotates in response to the compressed air flow. Figure 2 ) is operably coupled to a drive shaft 50 that provides a rotational output that will cause the turbine engine 14 ( Figure 2 ). The drive shaft 50 is rotatably supported by a first bearing 82 and a second bearing 84 .

[0087] During startup, pressurized fluid, such as but not limited to pressurized oil, is provided to the first fluid reservoir 116, the second fluid reservoir 136, or both the first fluid reservoir 116 and the second fluid reservoir 136. The oil pressure and volume in the first fluid reservoir 116 or the second fluid reservoir 136 is controlled by the first valve 130 or the second valve 150, or both the first valve 130 and the second valve 150.

[0088] Axial, radial, or axial and radial forces or loads are dissipated or distributed using the spring finger structure 92 , which supports the first bearing 82 using the first bearing support 104 and the second bearing 84 using the second bearing support 106 .

[0089] Axial loads on the first bearing 82 may be absorbed by the first bearing support 104 and / or transferred to the seal 40 or the housing 30 by the at least one flexible connector 108 .

[0090] When the first bearing support 104 deflects toward the seal 40, the radial load on the first bearing 82 can be damped, dissipated, distributed, or otherwise reduced by the first bearing support 104 and / or the first fluid reservoir 116. The first valve 130 controls the flow of fluid between the first fluid reservoir 116 and the fluid source 118. Controlling the flow of fluid into and out of the first fluid reservoir 116 allows control of the amount of radial deflection or damping provided by the first fluid reservoir 116. In addition, by allowing radial flexibility of the first bearing 82, at least a portion of the radial load on the first bearing 82 can be transferred to the second bearing 84.

[0091] The second bearing support 106 can absorb, distribute, transfer, or otherwise reduce the axial load on the second bearing 84. By way of non-limiting example, the spring 112 can absorb or reduce the axial load on the second bearing 84 by preloading at least the second outer race 96 of the second bearing 84. The second bearing support 106 can be made of a material capable of dissipating the axial load and / or transferring the axial load on the second bearing 84 to one or more portions of the seal 40 or the housing 30.

[0092] Increased radial loads on the second bearing 84 (due to increased compliance of the first bearing 82 ) may be dampened by controlling the second fluid reservoir 136 .

[0093] The second valve 150 controls fluid flow between the second fluid reservoir 136 and the fluid source 118 or another fluid source 148. Controlling the flow of fluid into and out of the second fluid reservoir 136 allows the amount of radial deflection or damping provided by the second fluid reservoir 136 to be controlled.

[0094] Furthermore, in addition to the second fluid reservoir 136 , a portion of the radial load on the second bearing 84 may be transferred and / or dampened by the material selected for the second bearing support 106 .

[0095] Damping the axial and radial loads or movement of the first bearing 82 and the second bearing 84 can extend the life of the ATS 10 and / or allow the drive shaft 50 to rotate at a higher speed. More specifically, increasing the radial load of the second bearing 84 reduces the radial load of the first bearing 82, thereby increasing the service life of the first bearing 82. The increased radial load on the second bearing 84 is at least dampened, transmitted, or otherwise reduced by the second fluid reservoir 136 to increase the service life of the second bearing 84. That is, the increase in radial load is mitigated or offset by the second fluid reservoir 136 and / or the spring finger structure 92.

[0096] Once the turbine engine 14 is started or self-sustaining, the clutch 66 may disconnect the shaft 62 from the carrier member 58. Additionally, once the turbine engine 14 has been started, the pressurized fluid provided to the first fluid reservoir 116 or the second fluid reservoir 136 to enhance the damping of the spring finger structure 92 may be stopped or otherwise allowed to reach an unpowered equilibrium.

[0097] In the event of reverse drive, the ATS 10 may be disconnected from the AGB 12 via the decoupler assembly 70 .

[0098] Figure 4 A cross section of a bearing assembly 280 having a fluid damping assembly 290 is shown, similar to Figure 3The bearing assembly 80 and the fluid damping assembly 90 are similar and therefore, like components will be identified by like numbers increased by 200, with the understanding that the description of like components of the bearing assembly 80 and the fluid damping assembly 90 applies to the bearing assembly 280 and the fluid damping assembly 290 unless otherwise specified.

[0099] The fluid damping assembly 290 may include a first fluid reservoir 116 positioned between the spring finger structure 92 and the first bearing support 104, a second fluid reservoir 136 positioned between the second bearing 84 and the second bearing support 106, and at least one fluid source, which is illustrated as the fluid source 118. The fluid damping assembly 290 may further include auxiliary fluid reservoirs, which are illustrated as a first auxiliary fluid reservoir 360 and a set of second auxiliary fluid reservoirs 362. The first auxiliary fluid reservoir 360 or the set of second auxiliary fluid reservoirs 362 may be coupled to the fluid source 118 via one or more first conduits 326 or second conduits 346.

[0100] The first auxiliary fluid reservoir 360 may be journaled, received in the seal 40 or the housing 30 ( Figure 2 ) within, defined by, supported by, or otherwise coupled to the seal 40 and the housing 30 ( Figure 2 ). The first auxiliary fluid reservoir 360 is fluidly coupled between the fluid source 118 and the first fluid reservoir 116. The first auxiliary fluid reservoir 360 provides additional control of the pressurized fluid in the fluid damping assembly 290, which is located between the fluid source 118 and the first fluid chamber 122. That is, instead of using only the first valve 130 to control flow or pressure, the first valve 130 and the first auxiliary fluid reservoir 360 can be used to control flow or pressure. The first auxiliary fluid reservoir 360 can be positioned radially between the first valve 130 and the first fluid chamber 122, although other positioning is contemplated.

[0101] The second auxiliary fluid reservoir 362 of the set can be journaled and accommodated in the seal 40 or the housing 30 ( Figure 2 ) within, defined by, supported by, or otherwise coupled to the seal 40 and the housing 30 ( Figure 2 ). The set of second auxiliary fluid reservoirs 362 is fluidly coupled between the fluid source 118 and the second fluid reservoir 136. The set of second auxiliary fluid reservoirs 362 provides additional control of the pressurized fluid in the fluid damping assembly 290, which is located between the fluid source 118 and the second fluid chamber 142. That is, instead of using only the second valve 150 to control flow or pressure, the second valve 150 and the set of second auxiliary fluid reservoirs 362 can be used to control flow or pressure.

[0102] One or more support portions 364 may be coupled to or integrally formed within the seal 40 that at least partially define one or more of the first auxiliary fluid reservoir 360 or the set of second auxiliary fluid reservoirs 362 .

[0103] As illustrated, by way of example, one or more of the set of second auxiliary fluid reservoirs 362 may be defined by the second bearing support 106 of the spring finger structure 92 .

[0104] The benefits associated with the spring finger structures and fluid damping assemblies described herein allow for longer life of the ATS bearings. In addition, by dissipating, damping and otherwise controlling the axial and radial forces on the bearings, this equates to better lubrication, which allows for more robust operation, such as allowing for faster rotation of the drive shaft.

[0105] The spring finger structure combined with the fluid damping assembly can provide reduced radial and axial loads on the bearing, which results in longer bearing life.

[0106] The flexibility provided by the finger-like structure in combination with the fluid damping assembly can allow a reduction in the normal radial load on the first bearing and an increase in the radial load on the second bearing. Aspects such as the second fluid reservoir and / or the second bearing support can mitigate, divert or otherwise reduce any increase in radial load on the second bearing.

[0107] In addition, a fluid damping assembly having a first fluid reservoir and a second fluid reservoir can provide differential damping to each of the two bearings. That is, the flow rate, volume or pressure of the fluid / oil provided to the first fluid chamber is controlled independently of the flow rate, volume or pressure of the fluid / oil provided to the second fluid chamber.

[0108] To the extent not yet described, the different features and structures of the various embodiments may be used in combination with or in place of one another as desired. The fact that a feature is not illustrated in all embodiments is not intended to be interpreted as meaning that it cannot be so illustrated, but rather is done for the sake of brevity of description. Thus, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not these new embodiments are explicitly described. The present disclosure covers all combinations or permutations of the features described herein.

[0109] This written description uses examples to describe aspects of the disclosure described herein, including the best mode, and also to enable any person skilled in the art to practice aspects of the disclosure, including making and using any device or circuit and performing any combined method. The patentable scope of aspects of the disclosure is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that have insubstantial differences from the literal language of the claims.

[0110] Further aspects are provided by the subject matter of the following clauses:

[0111] An air turbine starter for starting an engine comprises: a housing having an inlet, an outlet and an air flow path extending between the inlet and the outlet, wherein the housing includes a seal that defines at least a portion of the air flow path; a drive shaft rotatably coupled to the turbine, defining an axis of rotation and having circumferentially spaced blades at least partially disposed within the air flow path; at least one bearing rotatably supporting the drive shaft; a bearing support structure at least partially positioned between at least one bearing and the seal; and a fluid damping assembly including one or more conduits that fluidly couple a fluid source to a fluid reservoir, wherein the fluid reservoir includes a fluid cavity defined at least in part by a portion of the bearing support structure.

[0112] An air turbine starter according to any of the preceding clauses, wherein the fluid damping assembly further comprises a flow conditioning device coupled to or positioned within the one or more conduits.

[0113] An air turbine starter according to any of the preceding clauses, wherein the flow regulating device is a valve coupled to a controller or a power source.

[0114] An air turbine starter according to any of the preceding clauses, wherein the flow regulating device is a passive valve.

[0115] An air turbine starter according to any of the preceding clauses, wherein the flow conditioning device is positioned radially between the fluid source and the fluid reservoir.

[0116] An air turbine starter according to any of the preceding clauses, wherein the flow regulating device provides pressurized fluid to the fluid reservoir.

[0117] An air turbine starter according to any of the preceding clauses, wherein the pressurized fluid is pressurized oil.

[0118] An air turbine starter according to any of the preceding clauses, wherein the fluid source provides pressurized fluid to the fluid reservoir.

[0119] An air turbine starter according to any of the preceding clauses, wherein the pressurised fluid is pressurised oil.

[0120] An air turbine starter according to any of the preceding clauses, wherein the fluid cavity is defined by part of the bearing support structure, part of the seal and the side wall.

[0121] An air turbine starter according to any of the preceding clauses, wherein the side wall is press fit between portions of the bearing support structure and the seal.

[0122] The air turbine starter of claim 8, further comprising an auxiliary fluid reservoir fluidly connected to the fluid source and the fluid reservoir and positioned radially between the fluid source and the fluid reservoir.

[0123] An air turbine starter according to any of the preceding clauses, wherein the auxiliary fluid reservoir is a group of auxiliary fluid reservoirs positioned radially between the fluid source and the fluid reservoir, wherein each reservoir in the group of auxiliary fluid reservoirs is radially spaced apart from another reservoir in the group of auxiliary fluid reservoirs.

[0124] An air turbine starter according to any of the preceding clauses, wherein the bearing is a first bearing, the air turbine starting device comprises a second bearing, and the bearing support structure comprises a first bearing support adjacent the first bearing and a second bearing support adjacent the second bearing.

[0125] An air turbine starter according to any of the preceding clauses, wherein the bearing support structure comprises a spring finger structure defined by the first bearing support, the second bearing support and the at least one flexible connector.

[0126] An air turbine starter according to any of the preceding clauses, wherein the spring is positioned axially between one of the at least one flexible connector and the second bearing.

[0127] An air turbine starter according to any of the preceding clauses, wherein the fluid reservoir of the fluid damping assembly is a first fluid reservoir, the fluid damping assembly includes a second fluid reservoir, wherein the first fluid reservoir is positioned between the first bearing support and the seal, and the second fluid reservoir is axially spaced apart from the first fluid reservoir and positioned between the second bearing support and a portion of the second bearing.

[0128] An air turbine starter according to any of the preceding clauses, further comprising a first valve and a second valve, wherein the first valve is positioned between the fluid source and the first fluid reservoir, and the second valve is positioned between the fluid source and the second fluid reservoir.

[0129] An air turbine starter according to any of the preceding clauses, further comprising one or more of a pump, a flow sensor, a pressure sensor, a valve, a filter or a bleed line.

[0130] An air turbine starter according to any of the preceding clauses, wherein the fluid cavity is defined by part of the bearing support structure, part of the bearing and the side wall.

[0131] An air turbine starter according to any of the preceding clauses, wherein the side wall is press fit between part of the bearing support structure and part of the bearing.

[0132] An air turbine starter according to any of the preceding clauses, further comprising an auxiliary fluid reservoir fluidly connected to and radially positioned between the valve and the fluid reservoir positioned in the one or more conduits.

[0133] An air turbine starter according to any of the preceding clauses, wherein the fluid reservoir defines a fluid cavity which is a variable volume cavity that dampens radial movement of the bearing.

[0134] An air turbine starter according to any of the preceding clauses, wherein the fluid reservoir defines a fluid cavity which is a variable volume cavity that dampens radial movement of the bearing support structure.

[0135] An air turbine starter according to any of the preceding clauses, wherein the first fluid reservoir defines a first fluid chamber, which is a variable volume chamber that dampens radial movement of the first bearing, and the second fluid reservoir defines a second fluid chamber, which is a variable volume chamber that dampens radial movement of the second bearing support structure.

[0136] An air turbine starter according to any of the preceding clauses, wherein the set of flexible connectors defines a load path between the first bearing support and the second bearing support.

[0137] An air turbine starter according to any of the preceding clauses, wherein the first bearing and the second bearing are axially spaced relative to the axis of rotation.

[0138] An air turbine starter according to any of the preceding clauses, wherein the first or second bearing is a radial bearing and the second bearing or the first bearing is an axial bearing.

Claims

1. An air turbine starter for starting an engine, comprising: a housing having an inlet, an outlet, and an air flow path extending between the inlet and the outlet, wherein the housing includes a seal defining at least a portion of the air flow path; a drive shaft rotatably coupled to a turbine, defining an axis of rotation, the turbine having circumferentially spaced blades disposed at least partially within the air flow path; a bearing rotatably supporting the drive shaft; a bearing support structure positioned at least partially between the bearing and the seal; and A fluid damping assembly includes one or more conduits fluidly coupling a fluid source to a fluid reservoir, wherein the fluid reservoir includes a fluid cavity defined at least in part by portions of the bearing support structure.

2. The air turbine starter according to claim 1, wherein: The fluid damping assembly also includes a flow conditioning device coupled to or positioned within the one or more conduits.

3. The air turbine starter according to claim 2, wherein: The flow regulating device is a valve coupled to a controller or a power source.

4. The air turbine starter according to claim 2, wherein: The flow regulating device is positioned radially between the fluid source and the fluid reservoir.

5. The air turbine starter according to claim 2, wherein: The flow regulating device provides pressurized fluid to the fluid reservoir.

6. The air turbine starter according to claim 1, wherein: The fluid source provides pressurized fluid to the fluid reservoir.

7. The air turbine starter according to claim 6, wherein: The pressurized fluid is pressurized oil.

8. The air turbine starter according to any one of claims 1 to 5, wherein: The fluid cavity is defined by the portion of the bearing support structure, the portion of the seal, and a sidewall.

9. The air turbine starter according to claim 8, wherein: The side wall is press fit between the bearing support structure and the portion of the seal.

10. The air turbine starter of claim 8, further comprising an auxiliary fluid reservoir fluidly connected to the fluid source and the fluid reservoir and positioned radially between the fluid source and the fluid reservoir.

Images