Patent Publication Number: US-11661863-B2

Title: Air turbine starter

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to Polish Application No. P.434997, filed Aug. 18, 2020, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure generally relates to an air turbine starter, specifically the positioning of bearing assemblies in the air turbine starter. 
     BACKGROUND 
     A turbine engine, for example a gas turbine engine, is engaged in regular operation to an air turbine starter. Air turbine starters are typically mounted to the engine through a gear box or other transmission assembly. The transmission transfers power from the starter to the engine to assist in starting the engine. The internal components of both the turbine engine and the air turbine starter spin together such that the air turbine starter can be used to start the turbine engine. 
     A typical air turbine starter has a housing that is divided into a dry and wet portions by a seal structure. A turbine with a drive shaft is located in the dry portion, with part of the drive shaft extending through the seal structure. A gearbox with an output shaft is located in the wet portion and has an output shaft coupled to the engine. The drive shaft connects to the gear box such that rotation of the turbine rotates the drive shaft. The rotating drive shaft can rotate the gear box, which rotates the output shaft. 
     In typical air turbine starters, the bearing assemblies are a pair of axially spaced bearing assemblies, with first and second bearing assemblies upstream of the gear box. The first and second bearing assemblies rotatably supporting the drive shaft relative to one or more bearing housings in the seal structure. These bearings are subject to heat and stress during operation. 
     BRIEF DESCRIPTION 
     Aspects and advantages of the disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the disclosure. 
     In one aspect, the disclosure relates to an air turbine starter. The air turbine starter includes a housing having a primary inlet and primary outlet to define a primary air flow path from the primary inlet to the primary outlet. A gear box is located within a gearbox section of the air turbine starter. The gear box includes a drive shaft and an output shaft, with a gear train, including a carrier, operably coupling the drive shaft and the output shaft. A turbine includes a rotor that is coupled to the drive shaft, where the turbine further includes a plurality of circumferentially spaced blades extending from the rotor. A first bearing assembly rotatably supports at the drive shaft relative to the housing. A second bearing assembly rotatably supporting at least one of the carrier or the output shaft relative to at least one of the drive shaft or housing. 
     In another aspect, the disclosure relates to an air turbine starter that includes a housing defining an interior having a primary inlet and a primary outlet to define a primary air flow path from the primary inlet to the primary outlet. A turbine, located in the interior, includes a rotor with a plurality of circumferentially spaced blades that extend into the primary air flow path. A drive shaft operably couples with the turbine. A gear box is located in the interior and includes a gear train that couples to the drive shaft. A first bearing assembly rotatably supports the drive shaft and is located between the drive shaft and a first portion of the housing, a second bearing assembly configured to rotatably support a carrier coupled to the gear train, and a third bearing assembly configured to rotatably support the carrier and located between the carrier and a second portion of the housing. 
     These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended FIGs., in which: 
         FIG.  1    is a schematic illustration of a turbine engine with an air turbine starter. 
         FIG.  2    is an enlarged schematic cross-section view of a portion of the air turbine starter of  FIG.  1   . 
         FIG.  3    is a variation of the schematic cross-section of  FIG.  2   . 
         FIG.  4    is another variation of the schematic cross-section of  FIG.  2   . 
         FIG.  5    is yet another variation of the schematic cross-section of  FIG.  2   . 
         FIG.  6    is still yet another variation of the schematic cross-section of  FIG.  2   . 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the disclosure described herein are directed to a turbine engine with an air turbine starter that includes first and second bearing assemblies with an optional third bearing assembly. The first bearing assembly can be located in a more traditional location that is upstream of the gear box. The first bearing assembly can rotatably support the drive shaft relative to one or more portions of the housing or seal. The location of the second or third bearing assemblies, as disclosed herein, can reduce stress or heat experienced by one or more bearings in the air turbine starter. Further, additional bearing assemblies can be included to further rotatably support components, reduce stress, reduce heat, or allow the architecture of the air turbine starter to be more compact. 
     More specifically, the first bearing assembly rotatably supports the drive shaft relative to the housing, and the second bearing assembly rotatably supports at least one of the carrier or the output shaft relative to at least one of the drive shaft or housing. Even more specifically, the first bearing assembly can rotatably support the drive shaft relative to seal structure the second bearing assembly can rotatably support the carrier relative to the drive shaft. 
     For purposes of illustration, the present disclosure will be described with respect to an air turbine starter for an aircraft turbine engine. For example, the disclosure can have applicability in other vehicles or engines, and can be used to provide benefits in industrial, commercial, and residential applications. Further non-limiting examples of other vehicles or engines to which the disclosure can relate can include boats, cars, or other aquatic or land vehicles. Industrial, commercial, or residential applications of the disclosure can include, but are not limited to, marine power plants, wind turbines, small power plants, or helicopters. 
     As used herein, the term “upstream” refers to a direction that is opposite the fluid flow direction, and the term “downstream” refers to a direction that is in the same direction as the fluid flow. The term “fore” or “forward” means in front of something and “aft” or “rearward” means behind something. For example, when used in terms of fluid flow, fore/forward can mean upstream and aft/rearward can mean downstream. 
     Additionally, as used herein, the terms “radial” or “radially” refer to a direction away from a common center. For example, in the overall context of a turbine engine, radial refers to a direction along a ray extending between a center longitudinal axis of the engine and an outer engine circumference. Furthermore, as used herein, the term “set” or a “set” of elements can be any number of elements, including only one. 
     All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, aft, etc.) are only used for identification purposes to aid the reader&#39;s understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of aspects of the disclosure described herein. Connection references (e.g., attached, coupled, secured, fastened, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to one another. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary. 
     While illustrated as roller bearings, it is contemplated that any one or all of the bearings disclosed herein can be a ball bearing, tapered bearing, deep groove bearing, plane bearing, fluid bearing, flexture bearing, magnetic bearing, or any other structure or bearing that reduces friction of a rotating part. 
     Referring to  FIG.  1   , a starter motor or air turbine starter  10  is coupled to an accessory gear box (AGB)  12 , also known 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  comprises an air intake with a fan  16  that supplies air to a high pressure compression region  18 . The air intake with a fan  16  and the high pressure compression region collectively are known as the ‘cold section’ of the turbine engine  14  upstream of the combustion. The high pressure compression region  18  provides a combustion chamber  20  with high pressure air. In the combustion chamber, the high pressure air is mixed with fuel and combusted. The hot and pressurized combusted gas passes through a high pressure turbine region  22  and a low pressure turbine region  24  before exhausting from the turbine engine  14 . As the pressurized gases pass through the high pressure turbine (not shown) of the high pressure turbine region  22  and the low pressure turbine (not shown) of the low pressure turbine region  24 , the turbines extract rotational energy from the flow of the gases passing through the turbine engine  14 . The high pressure turbine of the high pressure turbine region  22  can be coupled to the compression mechanism (not shown) of the high pressure compression region  18  by way of a shaft to power the compression mechanism. The low pressure turbine can be coupled to the fan  16  of the air intake by way of the shaft to power the fan  16 . 
     The turbine engine can be a turbofan engine, such as a General Electric GEnx or CF6 series engine, commonly used in modern commercial and military aviation or it could be a variety of other known turbine engines such as a turboprop or turboshaft. 
     The AGB  12  is coupled to the turbine engine  14  at either the high pressure or low pressure turbine region  22 ,  24  by way of a mechanical power take-off  26 . The mechanical power take-off  26  contains multiple gears and means for mechanical coupling of the AGB  12  to the turbine engine  14 . Under normal operating conditions, the mechanical power take-off  26  translates power from the turbine engine  14  to the AGB  12  to power accessories of the aircraft for example but not limited to fuel pumps, electrical systems, and cabin environment controls. The air turbine starter  10  can be mounted on the outside of either the air intake region containing the fan  16  or on the core near the high pressure compression region  18 . Optionally, an air intake conduit  27  can couple to the air turbine starter  10 . The air intake conduit  27  can supply the air turbine starter  10  with pressurized air. 
     Referring now to  FIG.  2   , an exploded cross section of a portion of the air turbine starter  10 . Generally, the air turbine starter  10  includes a housing  30  defining an interior  28  having a primary inlet  32  and a primary outlet  34 . A primary air flow path  36 , illustrated schematically with an arrow, extends between the primary inlet  32  and the primary outlet  34  for communicating a flow of fluid, including, but not limited to gas, compressed air, or the like, there through. The primary outlet  34  can include a plurality of circumferentially arranged openings  38  in a peripheral wall  40  of the housing  30 . In this configuration, the primary inlet  32  is an axial inlet and the primary outlet  34  is a radial or circumferential outlet alone the periphery of the housing  30 . 
     The housing  30  can be made up of two or more parts that are combined together or can be integrally formed as a single piece. In the depicted aspects of the disclosure, the housing  30  of the air turbine starter  10  generally defines, in an axial series arrangement, an inlet turbine section  44 , a gearbox section  46 , and a drive section  48 . A seal structure  56  can be coupled to or unitarily formed with the housing  30 . It is contemplated that the seal structure  56  can divide the interior  28  into the inlet turbine section  44  and the gearbox section  46 . The air turbine starter  10  can be formed by any materials and methods, including, but not limited to, additive manufacturing or die-casting of high strength and lightweight metals such as aluminum, stainless steel, iron, or titanium. The housing  30  and the gearbox section  46  can be formed with a thickness sufficient to provide adequate mechanical rigidity without adding unnecessary weight to the air turbine starter  10  and, therefore, the aircraft. 
     The inlet turbine section  44  can include the primary inlet  32 , stationary portions  52 , a turbine  54 , the primary outlet  34 , and at least a portion of the seal structure  56 . In one non-limiting example fluid or air is supplied to the primary inlet  32  from either a ground-operating air cart, an auxiliary power unit, or a cross-bleed start from an engine already operating. The stationary portions  52  can guide air from the primary inlet  32  to the turbine  54  by defining at least a portion of a primary air flow path  36 . 
     The turbine  54  can include a disc or rotor  58  and a plurality of circumferentially spaced blades  60 . The rotor  58  can be mounted to the housing in a manner for rotation, for example, the rotor  58  can be circumscribed by the housing  30 . The plurality of circumferentially spaced blades  60  can be disposed in the primary air flow path  36  for rotatably extracting mechanical power from the flow of gas from the primary inlet  32  to the primary outlet  34 . The turbine  54 , the rotor  58 , and the plurality of circumferentially spaced blades  60  can rotate about a centerline or axis of rotation  62 . 
     The turbine  54  can further include a drive shaft  66 . The drive shaft  66  can be coupled to or is unitarily formed with the rotor  58  of the turbine  54  allowing for the transfer of energy from air in the primary air flow path  36  to mechanical power. The drive shaft  66  can extend through at least a portion of the inlet turbine section  44  or the gearbox section  46 . 
     The seal structure  56  can define a portion of the primary air flow path  36 . By way non-limiting example, a forward wall  70  of the seal structure  56  can guide air from the turbine  54  to the primary outlet  34 . The seal structure  56  can include a structural wall  57  that bears a seal  59 . The seal  59  can be proved between the structural wall  57  and the drive shaft  66 . 
     A rear wall  84  and a central wall  86  of the seal structure  56  can define a portion of a first cavity  78 . The first cavity  78  can be a wet portion of the housing  30 . That is, a turbine thrust bearing or first bearing assembly  74  or a turbine pre-load bearing or second bearing assembly  76  can be lubricated with a grease or oil in the first cavity  78  of the housing  30 . The first cavity  78  is a portion in the housing  30  that is exposed to grease, oil, or other know coolants or liquids, whereas a dry portion can be a cavity or portion that is not exposed to liquid. By way of non-limiting example of contrast, the forward side of the turbine  54  is a dry portion of the housing  30 . 
     By way of non-limiting example, the drive shaft  66  can couple the turbine  54  to one or more gears or clutch assemblies, such as a gear train  68 , in the gearbox section  46 . The gearbox section  46  can include at least a gear box  72  that can include the gear train  68 , the first bearing assembly  74 , the second bearing assembly  76 , the first cavity  78 , and an output shaft  80 . The gear box  72  can contain the gear train  68  that couples the drive shaft  66  to the output shaft  80 , so that when driven by the drive shaft  66 , the gear train  68  can transfer mechanical power to the output shaft  80 . The gear train  68  can, for example, be a planetary gear system with a sun gear, a ring gear, and planet gears, which are supported by a carrier  82 , which carries the output shaft  80  to the turbine engine  14 . However, any gear train  68  having the carrier  82  or similar structure that operably couples the drive shaft  66  to the output shaft  80  is contemplated. The carrier  82  can extend axially beyond the gear train  68 . 
     The first bearing assembly  74  can rotationally support the drive shaft  66  to one of the housing  30  or seal structure  56 . As illustrated, by way of non-limiting example, the first bearing assembly  74  is positioned between a first portion  88  of the central wall  86  of the seal structure  56  and the drive shaft  66 . That is, the first bearing assembly  74  can be circumscribed by the first portion  88  of the seal structure  56  where the first bearing assembly  74  rotatably supports the drive shaft  66  relative to the seal structure  56 . The first bearing assembly  74  can include a first bearing inner race  90  and a first bearing outer race  92 , with rollers located between the races. The first bearing inner race  90  can rotate with the drive shaft  66 , while the first bearing outer races  92  can be fixed relative the seal structure  56  or the housing  30 . A first radial distance  94  can be defined as the perpendicular distance from the axis of rotation  62  a first inner portion or the first bearing inner race  90 . 
     Axially, the first bearing assembly  74  can be located between the rotor  58  and the gear train  68 . That is, the first bearing assembly  74  can be downstream of the rotor  58  and upstream of the gear box  72  or gear train  68 . It is contemplated that the first bearing assembly  74  is fluidly coupled to the first cavity  78 . It is further contemplated that the first bearing assembly  74  can be lubricated using any number of systems. While illustrated as a single roller, the first bearing assembly  74  can include any number or style of rollers. 
     The second bearing assembly  76  can rotationally support at least one of the carrier  82  or output shaft  80  relative to at least one of the drive shaft  66  or housing  30 . As illustrated, by way of non-limiting example, the second bearing assembly  76  rotatably supports the carrier  82  relative to the drive shaft  66 . That is, the second bearing assembly  76  can be radially located between the drive shaft  66  and the carrier  82 . The second bearing assembly  76  can be circumscribed by the carrier  82  and rotationally support both the carrier  82  and the drive shaft  66 . 
     The second bearing assembly  76  pre-loads or takes some of the load from the first bearing assembly  74 . Pre-loading the first bearing assembly  74  can reduce the operating temperature of the first bearing assembly  74  which improves performance and life of the first bearing assembly  74 . 
     The first and second bearing assemblies  74 ,  76  can provide a saddle mount for the drive shaft  66 ; that is, there is at least one bearing assembly rotatably supporting the drive shaft  66  on each side of the gear box  72 . The saddle mount results in better alignment of the drive shaft  66  in the first bearing assembly  74  or thrust bearing. The saddle mount also provides better radial alignment of the drive shaft  66  in the second bearing assembly  76  and the gear train  68 . Further, the saddle mount also allows for a shorter axial length of the air turbine starter  10 , as only the first bearing assembly  74 , is located upstream of the gear box  72 . 
     The second bearing assembly  76  can include a second bearing inner race  96  and a second bearing outer race  98 , with rollers located between the races. As illustrated, the second bearing inner race  96  can rotate with the drive shaft  66 . The second bearing outer race  98  can rotate with the carrier  82 . That is, the second bearing inner and outer races  96 ,  98  can both rotate. A second radial distance  100  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the second bearing inner race  96 . The first radial distance  94  can be greater than or equal to the second radial distance  100 . However, it is contemplated that the first radial distance  94  can be less than the second radial distance  100 . 
     The second bearing assembly  76  can be axially located downstream of the gear box  72  or gear train  68 . It is contemplated that the second bearing assembly  76  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the second bearing assembly  76  can be lubricated using any number of systems. While illustrated as a single roller, the second bearing assembly  76  can include any number or style of rollers. 
     A carrier thrust bearing or third bearing assembly  102  can be included in the air turbine starter  10 . The third bearing assembly  102  can rotatably support the carrier  82 . As illustrated by way of non-limiting example, the third bearing assembly  102  is illustrated as rotatably supporting the carrier  82  relative to a second portion  104  of the housing  30 . The second portion  104  of the housing  30  can be a portion of an interior side  106  of the peripheral wall  40 . That is, the third bearing assembly  102  can be radially located between the carrier  82  and the peripheral wall  40  of the housing  30 . 
     The third bearing assembly  102  can include a third bearing inner race  108  and a third bearing outer race  110 , with rollers located between the races. As illustrated, the third bearing inner race  108  can rotate with the carrier  82 . The third bearing outer races  110  can be fixed relative the housing  30 . A third radial distance  112  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the third bearing inner race  108 . The third radial distance  112  can be greater than the first radial distance  94  or the second radial distance  100 . However, it is contemplated that the third radial distance  112  can be less than or equal to the first radial distance  94  or the second radial distance  100 . 
     The third bearing assembly  102  can be axially located downstream of the gear train  68 . It is contemplated that the third bearing assembly  102  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the third bearing assembly  102  can be lubricated using any number of systems. While illustrated as a single roller, the third bearing assembly  102  can include any number or style of rollers. 
     The third bearing assembly  102  can axially align with at least a portion of the second bearing assembly  76 . That is, at least a portion of the third bearing assembly  102  can circumscribe at least a portion of the second bearing assembly  76 . 
     The second bearing assembly  76  can preload or reduce forces on the third bearing assembly  102 . Further, the partial radial alignment of the third bearing assembly  102  and the second bearing assembly  76  can axially align the carrier  82  in the gear train  68 . 
     The location of the third bearing assembly  102  can provide radial stiffness to the second bearing assembly  76  through the transfer of support of the second bearing assembly  76  from the carrier  82  to the housing  30 . 
     A clutch thrust bearing or fourth bearing assembly  114  and a clutch preload bearing or fifth bearing assembly  116  can be included in the air turbine starter  10 . The fourth and fifth bearing assemblies  114 ,  116  can rotatably support the carrier  82  and a portion of an output arm  118 , where the output arm  118  can couple to the output shaft  80 . The output arm  118  can be selectively coupled to the carrier  82 . By way of non-limiting example, the output arm  118  and the carrier  82  can be coupled by one or more clutch assemblies (not shown). 
     As illustrated by way of non-limiting example, the fourth and fifth bearing assemblies  114 ,  116  are illustrated as rotatably supporting the carrier  82  and the output arm  118 . That is, the fourth and fifth bearing assemblies  114 ,  116  can be radially located between the carrier  82  and the output arm  118 . 
     The fourth and fifth bearing assemblies  114 ,  116  can include a fourth bearing inner race  120 , a fourth bearing outer race  122 , a fifth bearing inner race  124  and a fifth bearing outer race  126 , with rollers located between the corresponding races. As illustrated, the fourth and fifth bearing inner races  120 ,  124  can rotate with the carrier  82 . The fourth and fifth bearing outer races  122 ,  126  can rotate with the output arm  118 . A fourth radial distance  128  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fourth bearing inner race  120 . A fifth radial distance  130  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fifth bearing inner race  124 . 
     As illustrated, by way of non-limiting example, the fourth and fifth radial distance  128 ,  130  can be equal. However, it is contemplated that the fourth radial distance  128  can be greater than or less than the fifth radial distance  130 . 
     Similarly, the fourth and fifth radial distances  128 ,  130  can be greater than the first radial distance  94  or the second radial distance  100  and less than the third radial distance  112 , however, any combination is contemplated. 
     The fourth and fifth bearing assemblies  114 ,  116  can be axially located downstream of the gear train  68 . While illustrated as a single bearing assembly or as having a single roller, the fourth or fifth bearing assemblies  114 ,  116  can include any number of bearings assemblies or rollers. 
     The fifth bearing assembly  116  can preload or a reduce forces on the fourth bearing assembly  114 . Further, the fourth and fifth bearing assemblies  114 ,  116  can provide radial alignment and stability to the output shaft  80  about the axis  62 . The axial spacing between the fourth and fifth bearing assemblies  114 ,  116  provides radial support for the carrier  82 . 
     One or more portions of a clutch assembly  117  can be located between the fourth and fifth bearing assemblies  114 ,  116 . However, it is contemplated that one or more portions of the clutch assembly  117  can located upstream of the fourth bearing assembly  114  or downstream of the fifth bearing assembly  116 . The clutch assembly  117  can selectively engage the carrier  82  and the output shaft  80 . The fourth and fifth bearing assemblies  114 ,  116  can provide axial or radial stabilization for the clutch assembly  117 . 
     A drive preload bearing or sixth bearing assembly  132  can be included in the air turbine starter  10 . The sixth bearing assembly  132  can rotatably support the output arm  118 . As illustrated by way of non-limiting example, the sixth bearing assembly  132  is illustrated as rotatably supporting the output arm  118  relative to a third portion  134  of the housing  30 . The third portion  134  of the housing  30  an be a protrusion, extension, or additional structure(s) coupled to or formed with the housing  30 . That is, the sixth bearing assembly  132  can be radially located between the output arm  118  and the fourth portion of the housing  30 . The sixth bearing assembly  132  can be circumscribed by the housing  30  and rotationally support the output arm  118  relative to the housing  30 . 
     The sixth bearing assembly  132  can include a sixth bearing inner race  136  and a sixth bearing outer race  138 , with rollers located between the races. As illustrated, the sixth bearing inner race  136  can rotate with the output arm  118 . The sixth bearing outer races  138  can be fixed relative the housing  30 . A sixth radial distance  140  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the sixth bearing inner race  136 . As illustrated, by way of non-limiting example, the sixth radial distance  140  can be greater than the first radial distance  94 , the second radial distance  100 , the fourth radial distance  128 , or the fifth radial distance  130  and less than or equal to the third radial distance  112 , however, any combination is contemplated. 
     The sixth bearing assembly  132  can be axially located downstream of the gear train  68 . While illustrated as a single roller, the sixth bearing assembly  132  can include any number of rollers. While illustrated with six bearing assemblies, it is contemplated that the gearbox section  46  and the drive section  48  can include any number of bearing assemblies with any number or style of rollers. The partial radial alignment of the sixth bearing assembly  132  and the fifth bearing assembly  116  can axially align an output arm  118  or the output shaft  80  relative to the carrier  82 . 
     The location of the third bearing assembly  102  in relationship to the location of the fifth and sixth bearing assemblies  116 ,  132  reduces the dynamics of the carrier  82 . That is, the third, fifth, and sixth bearing assemblies  102 ,  116 ,  132  provide axial or radial support for the carrier  82 . The support provided to the carrier  82  can reduce vibrations of the carrier  82 . It is contemplated that the location of the third, fifth, and sixth bearing assemblies  102 ,  116 ,  132  can reduce vibration, axial force, or radial motion of other components of the starter  10 . 
     In operation, a fluid, for example air, is supplied to the air turbine starter  10 . The air enters the primary air flow path  36  through the primary inlet  32 . The energy from the air is transformed to mechanical energy by the turbine  54  which rotates in response to the air flow through the plurality of circumferentially spaced blades  60 . The rotor  58  of the turbine  54  is coupled to the drive shaft  66 , such that the rotational energy from the rotor  58  can be transferred to the gearbox section  46  via the drive shaft  66 . The drive shaft  66  is rotatably supported by at least one bearing assembly, illustrated by the first bearing assembly  74  and the second bearing assembly  76 . 
     The rotation of the drive shaft  66  rotates the sun gear in the gear train  68  of the gear box  72  in the gearbox section  46 . As the sun gear rotates, the sun gear can rotatably drive the planetary gears of the gear train  68 . That is, as the sun gear rotates, the planetary gears precess and rotate relative the fixed ring gear. The ring gear can be fixed to the seal structure  56 , the housing  30 , or other non-rotating portions of the air turbine starter  10 . The precessing planetary gears effect the rotation of the carrier  82 . That is, as the planetary gears precess, the carrier  82  can rotate. The carrier  82  can be rotatably supported by another bearing assembly, illustrated as the third, fourth, and fifth bearing assemblies  102 ,  114 ,  116 . 
     The carrier  82  can be selectively coupled to the output arm  118  or the output shaft  80  via one or more selectable assemblies, such as, but not limited to a clutch. The output arm  118  can be rotatably supported by, for example, the fourth, fifth, and sixth bearing assemblies  114 ,  116 ,  132 . The output shaft  80  provides rotational output that will result in starting the turbine engine  14 . 
       FIG.  3    is another example of an air turbine starter  210 . The air turbine starter  210  is similar to the air turbine starter  10 , therefore, like parts will be identified with like numerals increased by 200, with it being understood that the description of the like parts of the air turbine starter  10  apply to the air turbine starter  210 , unless otherwise noted. 
     Generally, the air turbine starter  210  includes the housing  30  defining the interior  28  having the primary inlet  32  and the primary outlet  34 . The primary air flow path  36 , illustrated schematically with an arrow, extends between the primary inlet  32  and the primary outlet  34  for communicating a flow of fluid, including, but not limited to gas, compressed air, or the like, there through. The primary outlet  34  can include the plurality of circumferentially arranged openings  38  in the peripheral wall  40  of the housing  30 . In this configuration, the primary inlet  32  is an axial inlet and the primary outlet  34  is a radial or circumferential outlet alone the periphery of the housing  30 . 
     The housing  30  can include, in an axial series arrangement, the inlet turbine section  44 , the gearbox section  46 , and the drive section  48 . The seal structure  56  can be coupled to or unitarily formed with the housing  30 . It is contemplated that the seal structure  56  can divide the interior  28  into the inlet turbine section  44  and the gearbox section  46 . 
     The inlet turbine section  44  can include the primary inlet  32 , stationary portions  52 , the turbine  54 , the primary outlet  34 , and at least a portion of the seal structure  56 . The stationary portions  52  can guide air from the primary inlet  32  to the turbine  54  by defining at least a portion of the primary air flow path  36 . 
     The turbine  54  can include the disc or rotor  58  and the plurality of circumferentially spaced blades  60 . The turbine  54 , the rotor  58 , and the plurality of circumferentially spaced blades  60  can rotate about the centerline or axis of rotation  62 . 
     The turbine  54  can further include the drive shaft  66 . The drive shaft  66  can be coupled to or is unitarily formed with the rotor  58  of the turbine  54  allowing for the transfer of energy from air in the primary air flow path  36  to mechanical power. The drive shaft  66  can extend through at least a portion of the inlet turbine section  44  or the gearbox section  46 . 
     The seal structure  56  can define a portion of the primary air flow path  36 . By way non-limiting example, the forward wall  70  of the seal structure  56  can guide air from the turbine  54  to the primary outlet  34 . The seal structure  56  can include the structural wall  57  that bears the seal  59 . The seal  59  can be proved between the structural wall  57  and the drive shaft  66 . 
     The rear wall  84  and a central wall  286  of the seal structure  56  can define a portion of the first cavity  78 . The first cavity  78  can be a wet portion of the housing  30 . That is, the turbine thrust bearing or first bearing assembly  74  or the turbine pre-load bearing or second bearing assembly  76  can be lubricated with a grease or oil in the first cavity  78  of the housing  30 . The first cavity  78  is a portion in the housing  30  that is exposed to grease, oil, or other know coolants or liquids. 
     By way of non-limiting example, the drive shaft  66  can couple the turbine  54  to one or more gears or clutch assemblies, such as the gear train  68 , in the gearbox section  46 . The gearbox section  46  can include at least the gear box  72  that can include the gear train  68 , the first bearing assembly  74 , the second bearing assembly  76 , the first cavity  78 , and the output shaft  80 . The gear box  72  can contain the gear train  68  that couples the drive shaft  66  to the output shaft  80 , so that when driven by the drive shaft  66 , the gear train  68  can transfer mechanical power to the output shaft  80 . The gear train  68  can, for example, be a planetary gear system with a sun gear, a ring gear, and planet gears, which are supported by a carrier  282 . The carrier  282  can include an upstream carrier portion  281  and a downstream carrier portion  283 . The upstream carrier portion  281  extends axially from the gear train  68  in the upstream direction towards the turbine  54 . The downstream carrier portion  283  extends axially from the gear train  68  in the downstream direction towards the output shaft  80  or downstream from the gear train  68 . Any gear train  68  having the carrier  282  or similar structure that operably couples the drive shaft  66  to the output shaft  80  is contemplated. 
     The first bearing assembly  74  can rotationally support the drive shaft  66  to one of the housing  30  or seal structure  56 . As illustrated, by way of non-limiting example, the first bearing assembly  74  is positioned between a first portion  288  of the central wall  286  of the seal structure  56  and the drive shaft  66 . That is, the first bearing assembly  74  can be circumscribed by the first portion  288  of the seal structure  56  where the first bearing assembly  74  rotatably supports the drive shaft  66  relative to the seal structure  56 . The first bearing assembly  74  can include the first bearing inner race  90  and the first bearing outer race  92 , with rollers located between the races. The first bearing inner race  90  can rotate with the drive shaft  66 , while the first bearing outer races  92  can be fixed relative the seal structure  56  or the housing  30 . A first radial distance  294  can be defined as the perpendicular distance from the axis of rotation  62  the first inner portion or the first bearing inner race  90 . 
     Axially, the first bearing assembly  74  can be located between the rotor  58  and the gear train  68 . That is, the first bearing assembly  74  can be downstream of the rotor  58  and upstream of the gear box  72  or gear train  68 . It is contemplated that the first bearing assembly  74  is fluidly coupled to the first cavity  78 . It is further contemplated that the first bearing assembly  74  can be lubricated using any number of systems. 
     The second bearing assembly  76  can rotationally support at least one of the carrier  282  or output shaft  80  relative to at least one of the drive shaft  66  or housing  30 . As illustrated, by way of non-limiting example, the second bearing assembly  76  rotatably supports the downstream carrier portion  283  relative to the drive shaft  66 . That is, the second bearing assembly  76  can be radially located between the drive shaft  66  and the downstream carrier portion  283 . The second bearing assembly  76  can be circumscribed by the downstream carrier portion  283  of the carrier  282  and rotationally support both the carrier  282  and the drive shaft  66 . 
     The second bearing assembly  76  pre-loads or takes some of the load from the first bearing assembly  74 . Pre-loading the first bearing assembly  74  can reduce the operating temperature of the first bearing assembly  74  which improves performance and life of the first bearing assembly  74 . 
     The first and second bearing assemblies  74 ,  76  provide the saddle mount for the drive shaft  66 . That is, there is at least one bearing assembly rotatably supporting the drive shaft  66  on each side of the gear box  72 . The saddle mount results in better alignment of the drive shaft  66  in the first bearing assembly  74  or thrust bearing. The saddle mount also provides better radial alignment of the drive shaft  66  in the second bearing assembly  76  and the gear train  68 . Further, the saddle mount also allows for a shorter axial length of the air turbine starter  210 , as only the first bearing assembly  74 , is located upstream of the gear box  72 . 
     The second bearing assembly  76  can include the second bearing inner race  96  and the second bearing outer race  98 , with rollers located between the races. As illustrated, the second bearing inner race  96  can rotate with the drive shaft  66 . The second bearing outer race  98  can rotate with the downstream carrier portion  283 . That is, the second bearing inner and outer races  96 ,  98  can both rotate. A second radial distance  300  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the second bearing inner race  96 . The first radial distance  294  can be greater than or equal to the second radial distance  300 . However, it is contemplated that the first radial distance  294  can be less than the second radial distance  300 . 
     The second bearing assembly  76  can be axially located downstream of the gear box  72  or gear train  68 . It is contemplated that the second bearing assembly  76  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the second bearing assembly  76  can be lubricated using any number of systems. 
     A carrier thrust bearing or third bearing assembly  302  can be included in the air turbine starter  210 . The third bearing assembly  302  can rotatably support the carrier  282 . As illustrated by way of non-limiting example, the third bearing assembly  302  is illustrated as rotatably supporting the upstream carrier portion  281  relative to a second portion  304  of the housing  30 . That is, the third bearing assembly  302  can be radially located between the upstream carrier portion  281  of the carrier  282  and the second portion  304  the housing  30 . 
     The third bearing assembly  302  can include a third bearing inner race  308  and a third bearing outer race  310 , with rollers located between the races. As illustrated, the third bearing inner race  308  can rotate with the upstream carrier portion  281 . The third bearing outer races  310  can be fixed relative the housing  30  at the second position  304 . A third radial distance  312  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the third bearing inner race  308 . The third radial distance  312  can be greater than the first radial distance  294  or the second radial distance  300 . However, it is contemplated that the third radial distance  312  can be less than or equal to the first radial distance  294  or the second radial distance  300 . 
     The third bearing assembly  302  can be axially located upstream of the gear train  68 . It is contemplated that the third bearing assembly  302  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the third bearing assembly  302  can be lubricated using any number of systems. While illustrated as a single roller, the third bearing assembly  302  can include any number or style of rollers. 
     The second bearing assembly  76  and the third bearing assembly  302  can provide a saddle mount for the carrier  282 , as each of the bearing that rotatably support the carrier  282  are on either side of the gear train  68 . This radially improves alignment of the carrier  282  in the gear train  68 . 
     The second bearing assembly  76  or the third bearing assembly  302  can have steel sleeves that mount into aluminum housing which can reduce the weight of the starter  10 . Further, the saddle mount for the carrier  282  provided by the second and third bearing assemblies  76 ,  302  can reduce the overall size of the starter  10 . Further, the location of the gear box  72  as provided by the location of the second and third bearing assemblies  76 ,  302  can allow the gearbox to be positioned closer to the AGB  12 , decreasing inertia moments. 
     The clutch thrust bearing or fourth bearing assembly  114  and the clutch preload bearing or fifth bearing assembly  116  can be included in the air turbine starter  210 . The fourth and fifth bearing assemblies  114 ,  116  can rotatably support the carrier  282  or an engagement structure  285  and a portion of an output arm  118 , where the output arm  118  can couple to the output shaft  80 . The fourth and fifth bearing assemblies  114 ,  116  can be axially located downstream of the gear train  68 . 
     The output arm  118  can be selectively coupled to the carrier  282  or engagement structure  285 . The engagement structure  285  can be selectively coupled or fixed to the downstream carrier portion  283 . That is, any number of assemblies (not shown) or selectable coupling devices or techniques (not shown) are contemplated at the interface of the carrier  282  and the engagement structure  285  or at the interface of the engagement structure  285  and the output arm  118  or output shaft  80 . It is contemplated that the engagement structure  285  and respective bearing assemblies can be replaced with the clutch assembly  117  illustrated in  FIG.  2   . 
     As illustrated by way of non-limiting example, the fourth and fifth bearing assemblies  114 ,  116  are illustrated as rotatably supporting the downstream carrier portion  283  and the output arm  118 . That is, the fourth and fifth bearing assemblies  114 ,  116  can be radially located between the downstream carrier portion  283  and the output arm  118 . 
     The fourth and fifth bearing assemblies  114 ,  116  can include the fourth bearing inner race  120 , the fourth bearing outer race  122 , the fifth bearing inner race  124  and the fifth bearing outer race  126 , with rollers located between the corresponding races. As illustrated, the fourth and fifth bearing inner races  120 ,  124  can rotate with the downstream carrier portion  283 . The fourth and fifth bearing outer races  122 ,  126  can rotate with the output arm  118 . A fourth radial distance  328  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fourth bearing inner race  120 . A fifth radial distance  330  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fifth bearing inner race  124 . 
     As illustrated, by way of non-limiting example, the fourth and fifth radial distance  328 ,  330  can be equal. However, it is contemplated that the fourth radial distance  328  can be greater than or less than the fifth radial distance  330 . 
     The fourth and fifth radial distances  328 ,  330  can be greater than the first radial distance  294 , the second radial distance  300 , or the third radial distance  312 . However, any combination of greater than, less than, or equal to among the first, second, third, fourth, and fifth radial distances  294 ,  300 ,  312 ,  328 ,  330  is contemplated. 
     The partial radial alignment of the fourth bearing assembly  114  and the second bearing assembly  76  can help axially align the carrier  282  relative to the gear train  68  and the drive shaft  66 . The fifth bearing assembly  116  can preload or a reduce forces on the fourth bearing assembly  114 . Further, the fourth and fifth bearing assemblies  114 ,  116  can provide radial alignment and stability to the output shaft  80  about the axis  62 . The axial spacing between the fourth and fifth bearing assemblies  114 ,  116  provides radial support for the carrier  82 . Further, the fourth and fifth bearing assemblies  114 ,  116  can provide axial and radial stabilization for the engagement structure  285 . Additionally, or alternatively, the fourth and fifth bearing assemblies  114 ,  116  can provide support for one or more clutch assemblies. 
     A drive preload bearing or sixth bearing assembly  332  can be included in the air turbine starter  210 . The sixth bearing assembly  332  can rotatably support the output arm  118 . As illustrated by way of non-limiting example, the sixth bearing assembly  332  is illustrated as rotatably supporting the output arm  118  relative to a third portion  334  of the housing  30 . The third portion  334  of the housing  30  an be a protrusion, extension, or additional structure(s) coupled to or formed with the housing  30 . That is, the sixth bearing assembly  332  can be radially located between the output arm  118  and the third portion  334  of the housing  30 . The sixth bearing assembly  332  can be circumscribed by the housing  30  and rotationally support the output arm  118  relative to the housing  30 . 
     The sixth bearing assembly  332  can include a sixth bearing inner race  336  and a sixth bearing outer race  338 , with rollers located between the races. As illustrated, the sixth bearing inner race  336  can rotate with the output arm  118 . The sixth bearing outer races  338  can be fixed relative the housing  30 . A sixth radial distance  340  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the sixth bearing inner race  336 . As illustrated, by way of non-limiting example, the sixth radial distance  340  can be greater than the first, second, third, fourth, and fifth radial distances  294 ,  300 ,  312 ,  328 ,  330 , however, any combination is contemplated. 
     The sixth bearing assembly  332  can be axially located downstream of the gear train  68 . While illustrated as a single roller, the sixth bearing assembly  332  can include any number of rollers. While illustrated with six bearing assemblies, it is contemplated that the gearbox section  46  and the drive section  48  of the air turbine starter  210  can include any number of bearing assemblies with any number or style of rollers. The sixth bearing assembly  332  can provide axial or radial stiffness or support to the output shaft  80 , the drive shaft  66 , or the engagement structure  285 . 
       FIG.  4    is another example of an air turbine starter  410 . The air turbine starter  410  is similar to the air turbine starter  10 ,  210  therefore, like parts will be identified with like numerals further increased by 200, with it being understood that the description of the like parts of the air turbine starter  10 ,  210  apply to the air turbine starter  410 , unless otherwise noted. 
     Generally, the air turbine starter  410  includes the housing  30  defining the interior  28  having the primary inlet  32  and the primary outlet  34 . The primary air flow path  36 , illustrated schematically with an arrow, extends between the primary inlet  32  and the primary outlet  34  for communicating a flow of fluid, including, but not limited to gas, compressed air, or the like, there through. The primary outlet  34  can include the plurality of circumferentially arranged openings  38  in the peripheral wall  40  of the housing  30 . In this configuration, the primary inlet  32  is an axial inlet and the primary outlet  34  is a radial or circumferential outlet alone the periphery of the housing  30 . 
     The housing  30  can include, in an axial series arrangement, the inlet turbine section  44 , the gearbox section  46 , and the drive section  48 . The seal structure  56  can be coupled to or unitarily formed with the housing  30 . It is contemplated that the seal structure  56  can divide the interior  28  into the inlet turbine section  44  and the gearbox section  46 . 
     The inlet turbine section  44  can include the primary inlet  32 , stationary portions  52 , the turbine  54 , the primary outlet  34 , and at least a portion of the seal structure  56 . The stationary portions  52  can guide air from the primary inlet  32  to the turbine  54  by defining at least a portion of the primary air flow path  36 . 
     The turbine  54  can include the disc or rotor  58  and the plurality of circumferentially spaced blades  60 . The turbine  54 , the rotor  58 , and the plurality of circumferentially spaced blades  60  can rotate about the centerline or axis of rotation  62 . 
     The turbine  54  can further include the drive shaft  66 . The drive shaft  66  can be coupled to or is unitarily formed with the rotor  58  of the turbine  54  allowing for the transfer of energy from air in the primary air flow path  36  to mechanical power. The drive shaft  66  can extend through at least a portion of the inlet turbine section  44  or the gearbox section  46 . 
     The seal structure  56  can define a portion of the primary air flow path  36 . By way non-limiting example, the forward wall  70  of the seal structure  56  can guide air from the turbine  54  to the primary outlet  34 . The seal structure  56  can include the structural wall  57  that bears the seal  59 . The seal  59  can be proved between the structural wall  57  and the drive shaft  66 . 
     The rear wall  84  and a central wall  486  of the seal structure  56  can define a portion of the first cavity  78 . The first cavity  78  can be a wet portion of the housing  30 . That is, the turbine thrust bearing or first bearing assembly  74  or the turbine pre-load bearing or second bearing assembly  76  can be lubricated with a grease or oil in the first cavity  78  of the housing  30 . The first cavity  78  is a portion in the housing  30  that is exposed to grease, oil, or other know coolants or liquids. 
     By way of non-limiting example, the drive shaft  66  can couple the turbine  54  to one or more gears or clutch assemblies, such as the gear train  68 , in the gearbox section  46 . The gearbox section  46  can include at least the gear box  72  that can include the gear train  68 , the first bearing assembly  74 , the second bearing assembly  76 , the first cavity  78 , and the output shaft  80 . The gear box  72  can contain the gear train  68  that couples the drive shaft  66  to the output shaft  80 , so that when driven by the drive shaft  66 , the gear train  68  can transfer mechanical power to the output shaft  80 . The gear train  68  can, for example, be a planetary gear system with a sun gear, a ring gear, and planet gears, which are supported by a carrier  482 . The carrier  482  can include an upstream carrier portion  481  and a downstream carrier portion  483 . The upstream carrier portion  481  extends axially from the gear train  68  in the upstream direction towards the turbine  54 . The downstream carrier portion  483  extends axially from the gear train  68  in the downstream direction towards the output shaft  80  or downstream from the gear train  68 . Any gear train  68  having the carrier  482  or similar structure that operably couples the drive shaft  66  to the output shaft  80  is contemplated. 
     The first bearing assembly  74  can rotationally support the drive shaft  66  to one of the housing  30  or seal structure  56 . As illustrated, by way of non-limiting example, the first bearing assembly  74  is positioned between a first portion  488  of the central wall  486  of the seal structure  56  and the drive shaft  66 . That is, the first bearing assembly  74  can be circumscribed by the first portion  88  of the seal structure  56  where the first bearing assembly  74  rotatably supports the drive shaft  66  relative to the seal structure  56 . The first bearing assembly  74  can include the first bearing inner race  90  and the first bearing outer race  92 , with rollers located between the races. The first bearing inner race  90  can rotate with the drive shaft  66 , while the first bearing outer races  92  can be fixed relative the seal structure  56  or the housing  30 . A first radial distance  294  can be defined as the perpendicular distance from the axis of rotation  62  the first inner portion or the first bearing inner race  90 . 
     Axially, the first bearing assembly  74  can be located between the rotor  58  and the gear train  68 . That is, the first bearing assembly  74  can be downstream of the rotor  58  and upstream of the gear box  72  or gear train  68 . It is contemplated that the first bearing assembly  74  is fluidly coupled to the first cavity  78 . It is further contemplated that the first bearing assembly  74  can be lubricated using any number of systems. 
     The second bearing assembly  76  can rotationally support at least one of the carrier  482  or output shaft  80  relative to at least one of the drive shaft  66  or housing  30 . As illustrated, by way of non-limiting example, the second bearing assembly  76  rotatably supports the downstream carrier portion  483  relative to the drive shaft  66 . That is, the second bearing assembly  76  can be radially located between the drive shaft  66  and the downstream carrier portion  483 . The second bearing assembly  76  can be circumscribed by the downstream carrier portion  483  of the carrier  482  and rotationally support both the carrier  482  and the drive shaft  66 . 
     The second bearing assembly  76  pre-loads or takes some of the load from the first bearing assembly  74 . Pre-loading the first bearing assembly  74  can reduce the operating temperature of the first bearing assembly  74  which improves performance and life of the first bearing assembly  74 . 
     The first and second bearing assemblies  74 ,  76  provide the saddle mount for the drive shaft  66 . That is, there is at least one bearing assembly rotatably supporting the drive shaft  66  on each side of the gear box  72 . The saddle mount results in better alignment of the drive shaft  66  in the first bearing assembly  74  or thrust bearing. The saddle mount also provides better radial alignment of the drive shaft  66  in the second bearing assembly  76  and the gear train  68 . Further, the saddle mount also allows for a shorter axial length of the air turbine starter  410 , as only the first bearing assembly  74 , is located upstream of the gear box  72 . 
     The second bearing assembly  76  can include the second bearing inner race  96  and the second bearing outer race  98 , with rollers located between the races. As illustrated, the second bearing inner race  96  can rotate with the drive shaft  66 . The second bearing outer race  98  can rotate with the downstream carrier portion  483 . That is, the second bearing inner and outer races  96 ,  98  can both rotate. A second radial distance  300  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the second bearing inner race  96 . The first radial distance  294  can be greater than or equal to the second radial distance  300 . However, it is contemplated that the first radial distance  294  can be less than the second radial distance  300 . 
     The second bearing assembly  76  can be axially located downstream of the gear box  72  or gear train  68 . It is contemplated that the second bearing assembly  76  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the second bearing assembly  76  can be lubricated using any number of systems. 
     A carrier thrust bearing or third bearing assembly  502  can be included in the air turbine starter  410 . The third bearing assembly  502  can rotatably support the carrier  482 . As illustrated by way of non-limiting example, the third bearing assembly  502  is illustrated as rotatably supporting the upstream carrier portion  481  relative to a second portion  504  of the housing  30 . That is, the third bearing assembly  502  can be radially located between the upstream carrier portion  481  of the carrier  482  and the second portion  504  the housing  30 . 
     The third bearing assembly  502  can include a third bearing inner race  508  and a third bearing outer race  510 , with rollers located between the races. As illustrated, the third bearing inner race  508  can rotate with the upstream carrier portion  481 . The third bearing outer races  510  can be fixed relative the housing  30  at the second position  504 . A third radial distance  512  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the third bearing inner race  508 . The third radial distance  512  can be greater than the first radial distance  294  or the second radial distance  300 . However, it is contemplated that the third radial distance  512  can be less than or equal to the first radial distance  294  or the second radial distance  300 . 
     The third bearing assembly  502  can be axially located upstream of the gear train  68 . It is contemplated that the third bearing assembly  502  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the third bearing assembly  502  can be lubricated using any number of systems. While illustrated as a single roller, the third bearing assembly  502  can include any number or style of rollers. 
     The second bearing assembly  76  and the third bearing assembly  502  can provide a saddle mount for the carrier  482 , as each of the bearing that rotatably support the carrier  482  are on either side of the gear train  68 . This radially improves alignment of the carrier  482  in the gear train  68 . 
     The second bearing assembly  76  or the third bearing assembly  502  can have steel sleeves that mount into aluminum housing which can reduce the weight of the starter  10 . Further, the saddle mount for the carrier  482  provided by the second and third bearing assemblies  76 ,  502  can reduce the overall size of the starter  10 . Further, the location of the gear box  72  as provided by the location of the second and third bearing assemblies  76 ,  502  can allow the gearbox to be positioned closer to the AGB  12 , decreasing inertia moments. 
     The clutch thrust bearing or fourth bearing assembly  114  and the clutch preload bearing or fifth bearing assembly  116  can be included in the air turbine starter  410 . The fourth and fifth bearing assemblies  114 ,  116  can rotatably support the carrier  282  or an engagement structure  285  and a portion of an output arm  118 , where the output arm  118  can couple to the output shaft  80 . The fourth and fifth bearing assemblies  114 ,  116  can be axially located downstream of the gear train  68 . 
     The output arm  118  can be selectively coupled to the carrier  482  or engagement structure  285 . The engagement structure  285  can be selectively coupled or fixed to the downstream carrier portion  483 . That is, any number of assemblies (not shown) or selectable coupling devices or techniques (not shown) are contemplated at the interface of the carrier  482  and the engagement structure  285  or at the interface of the engagement structure  285  and the output arm  118  or output shaft  80 . 
     As illustrated by way of non-limiting example, the fourth and fifth bearing assemblies  114 ,  116  are illustrated as rotatably supporting the downstream carrier portion  483  and the output arm  118 . That is, the fourth and fifth bearing assemblies  114 ,  116  can be radially located between the downstream carrier portion  283  and the output arm  118 . 
     The fourth and fifth bearing assemblies  114 ,  116  can include the fourth bearing inner race  120 , the fourth bearing outer race  122 , the fifth bearing inner race  124  and the fifth bearing outer race  126 , with rollers located between the corresponding races. As illustrated, the fourth and fifth bearing inner races  120 ,  124  can rotate with the downstream carrier portion  483 . The fourth and fifth bearing outer races  122 ,  126  can rotate with the output arm  118 . A fourth radial distance  328  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fourth bearing inner race  120 . A fifth radial distance  330  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fifth bearing inner race  124 . 
     As illustrated, by way of non-limiting example, the fourth and fifth radial distance  328 ,  330  can be equal. However, it is contemplated that the fourth radial distance  328  can be greater than or less than the fifth radial distance  330 . 
     The fourth and fifth radial distances  328 ,  330  can be greater than the first radial distance  294 , the second radial distance  300 , or the third radial distance  512 . However, any combination of greater than, less than, or equal to among the first, second, third, fourth, and fifth radial distances  294 ,  300 ,  512 ,  328 ,  330  is contemplated. 
     The partial radial alignment of the fourth bearing assembly  114  and the second bearing assembly  76  can help axially align the carrier  482  relative to the gear train  68  and the drive shaft  66 . The fifth bearing assembly  116  can preload or a reduce forces on the fourth bearing assembly  114 . 
     A drive preload bearing or sixth bearing assembly  332  can be included in the air turbine starter  410 . The sixth bearing assembly  332  can rotatably support the output arm  118 . As illustrated by way of non-limiting example, the sixth bearing assembly  332  is illustrated as rotatably supporting the output arm  118  relative to a third portion  334  of the housing  30 . The third portion  334  of the housing  30  an be a protrusion, extension, or additional structure(s) coupled to or formed with the housing  30 . That is, the sixth bearing assembly  332  can be radially located between the output arm  118  and the third portion  334  of the housing  30 . The sixth bearing assembly  332  can be circumscribed by the housing  30  and rotationally support the output arm  118  relative to the housing  30 . 
     The sixth bearing assembly  332  can include a sixth bearing inner race  336  and a sixth bearing outer race  338 , with rollers located between the races. As illustrated, the sixth bearing inner race  336  can rotate with the output arm  118 . The sixth bearing outer races  338  can be fixed relative the housing  30 . A sixth radial distance  340  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the sixth bearing inner race  336 . As illustrated, by way of non-limiting example, the sixth radial distance  340  can be greater than the first, second, third, fourth, and fifth radial distances  294 ,  300 ,  312 ,  328 ,  330 , however, any combination is contemplated. 
     The sixth bearing assembly  332  can be axially located downstream of the gear train  68 . While illustrated as a single roller, the sixth bearing assembly  332  can include any number of rollers. While illustrated with six bearing assemblies, it is contemplated that the gearbox section  46  and the drive section  48  of the air turbine starter  410  can include any number of bearing assemblies with any number or style of rollers. 
       FIG.  5    is yet another example of an air turbine starter  610 . The air turbine starter  610  is similar to the air turbine starter  10 ,  210 ,  410  therefore, like parts will be identified with like numerals further increased by 200, with it being understood that the description of the like parts of the air turbine starter  10 ,  210 ,  410  apply to the air turbine starter  610 , unless otherwise noted. 
     Generally, the air turbine starter  610  includes the housing  30  defining the interior  28  having the primary inlet  32  and the primary outlet  34 . The primary air flow path  36 , illustrated schematically with an arrow, extends between the primary inlet  32  and the primary outlet  34  for communicating a flow of fluid, including, but not limited to gas, compressed air, or the like, there through. The primary outlet  34  can include the plurality of circumferentially arranged openings  38  in the peripheral wall  40  of the housing  30 . In this configuration, the primary inlet  32  is an axial inlet and the primary outlet  34  is a radial or circumferential outlet alone the periphery of the housing  30 . 
     The housing  30  can include, in an axial series arrangement, the inlet turbine section  44 , the gearbox section  46 , and the drive section  48 . The seal structure  56  can be coupled to or unitarily formed with the housing  30 . It is contemplated that the seal structure  56  can divide the interior  28  into the inlet turbine section  44  and the gearbox section  46 . 
     The inlet turbine section  44  can include the primary inlet  32 , stationary portions  52 , the turbine  54 , the primary outlet  34 , and at least a portion of the seal structure  56 . The stationary portions  52  can guide air from the primary inlet  32  to the turbine  54  by defining at least a portion of the primary air flow path  36 . 
     The turbine  54  can include the disc or rotor  58  and the plurality of circumferentially spaced blades  60 . The turbine  54 , the rotor  58 , and the plurality of circumferentially spaced blades  60  can rotate about the centerline or axis of rotation  62 . 
     The turbine  54  can further include the drive shaft  66 . The drive shaft  66  can be coupled to or is unitarily formed with the rotor  58  of the turbine  54  allowing for the transfer of energy from air in the primary air flow path  36  to mechanical power. The drive shaft  66  can extend through at least a portion of the inlet turbine section  44  or the gearbox section  46 . 
     The seal structure  56  can define a portion of the primary air flow path  36 . By way non-limiting example, the forward wall  70  of the seal structure  56  can guide air from the turbine  54  to the primary outlet  34 . The seal structure  56  can include the structural wall  57  that bears the seal  59 . The seal  59  can be proved between the structural wall  57  and the drive shaft  66 . 
     The rear wall  84  and a central wall  686  of the seal structure  56  can define a portion of the first cavity  78 . The first cavity  78  can be a wet portion of the housing  30 . That is, the turbine thrust bearing or first bearing assembly  74  or a turbine pre-load bearing or second bearing assembly  676  can be lubricated with a grease or oil in the first cavity  78  of the housing  30 . The first cavity  78  is a portion in the housing  30  that is exposed to grease, oil, or other know coolants or liquids. 
     By way of non-limiting example, the drive shaft  66  can couple the turbine  54  to one or more gears or clutch assemblies, such as the gear train  68 , in the gearbox section  46 . The gearbox section  46  can include at least the gear box  72  that can include the gear train  68 , the first bearing assembly  74 , the second bearing assembly  676 , the first cavity  78 , and the output shaft  80 . The gear box  72  can contain the gear train  68  that couples the drive shaft  66  to the output shaft  80 , so that when driven by the drive shaft  66 , the gear train  68  can transfer mechanical power to the output shaft  80 . The gear train  68  can, for example, be a planetary gear system with a sun gear, a ring gear, and planet gears, which are supported by a carrier  682 . The carrier  682  can include an upstream carrier portion  681  and a downstream carrier portion  683 . The upstream carrier portion  681  extends axially from the gear train  68  in the upstream direction towards the turbine  54 . The downstream carrier portion  683  extends axially from the gear train  68  in the downstream direction towards the output shaft  80  or downstream from the gear train  68 . Any gear train  68  having the carrier  682  or similar structure that operably couples the drive shaft  66  to the output shaft  80  is contemplated. 
     The first bearing assembly  74  can rotationally support the drive shaft  66  to one of the housing  30  or seal structure  56 . As illustrated, by way of non-limiting example, the first bearing assembly  74  is positioned between a first portion  688  of the central wall  686  of the seal structure  56  and the drive shaft  66 . That is, the first bearing assembly  74  can be circumscribed by the first portion  688  of the seal structure  56  where the first bearing assembly  74  rotatably supports the drive shaft  66  relative to the seal structure  56 . The first bearing assembly  74  can include the first bearing inner race  90  and the first bearing outer race  92 , with rollers located between the races. The first bearing inner race  90  can rotate with the drive shaft  66 , while the first bearing outer races  92  can be fixed relative the seal structure  56  or the housing  30 . A first radial distance  694  can be defined as the perpendicular distance from the axis of rotation  62  the first inner portion or the first bearing inner race  90 . 
     Axially, the first bearing assembly  74  can be located between the rotor  58  and the gear train  68 . That is, the first bearing assembly  74  can be downstream of the rotor  58  and upstream of the gear box  72  or gear train  68 . It is contemplated that the first bearing assembly  74  is fluidly coupled to the first cavity  78 . It is further contemplated that the first bearing assembly  74  can be lubricated using any number of systems. 
     The second bearing assembly  676  can rotationally support at least one of the carrier  682  or output shaft  80  relative to at least one of the drive shaft  66  or housing  30 . As illustrated, by way of non-limiting example, the second bearing assembly  676  rotatably supports the upstream carrier portion  681  relative to the drive shaft  66 . That is, the second bearing assembly  676  can be radially located between the drive shaft  66  and the upstream carrier portion  681  of the carrier  682 . The second bearing assembly  676  can be circumscribed by the upstream carrier portion  681  of the carrier  682  and rotationally support both the carrier  682  and the drive shaft  66 . 
     The second bearing assembly  676  pre-loads or takes some of the load from the first bearing assembly  74 . Pre-loading the first bearing assembly  74  can reduce the operating temperature of the first bearing assembly  74  which improves performance and life of the first bearing assembly  74 . 
     The second bearing assembly  676  can include a second bearing inner race  696  and a second bearing outer race  698 , with rollers located between the races. As illustrated, the second bearing inner race  696  can rotate with the drive shaft  66 . The second bearing outer race  698  can rotate with the upstream carrier portion  681 . That is, the second bearing inner and outer races  696 ,  698  can both rotate. A second radial distance  700  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the second bearing inner race  696 . The first radial distance  694  can be equal to the second radial distance  700 . However, it is contemplated that the first radial distance  694  can be less than or greater than the second radial distance  700 . 
     The second bearing assembly  676  can be axially located upstream of the gear box  72  or gear train  68 . It is contemplated that the second bearing assembly  676  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the second bearing assembly  676  can be lubricated using any number of systems. 
     The carrier thrust bearing or third bearing assembly  102  can be included in the air turbine starter  610 . The third bearing assembly  102  can rotatably support the carrier  682 . As illustrated by way of non-limiting example, the third bearing assembly  102  is illustrated as rotatably supporting the downstream carrier portion  683  relative to a second portion  704  of the housing  30 . That is, the third bearing assembly  102  can be radially located between the downstream carrier portion  683  of the carrier  682  and the second portion  704  the housing  30 . 
     The third bearing assembly  102  can include the third bearing inner race  108  and the third bearing outer race  110 , with rollers located between the races. As illustrated, the third bearing inner race  108  can rotate with the downstream carrier portion  683 . The third bearing outer races  110  can be fixed relative the housing  30  at the second position  704 . A third radial distance  712  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the third bearing inner race  108 . The third radial distance  712  can be greater than the first radial distance  694  or the second radial distance  700 . However, it is contemplated that the third radial distance  712  can be less than or equal to the first radial distance  694  or the second radial distance  700 . 
     The third bearing assembly  102  can be axially located downstream of the gear train  68 . It is contemplated that the third bearing assembly  102  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the third bearing assembly  102  can be lubricated using any number of systems. While illustrated as a single roller, the third bearing assembly  102  can include any number or style of rollers. 
     The second bearing assembly  676  and the third bearing assembly  102  can provide a saddle mount for the carrier  682 , as each of the bearing that rotatably support the carrier  682  are on either side of the gear train  68 . This radially improves alignment of the carrier  682  in the gear train  68 . 
     The clutch thrust bearing or fourth bearing assembly  114  and the clutch preload bearing or fifth bearing assembly  116  can be included in the air turbine starter  610 . The fourth and fifth bearing assemblies  114 ,  116  can rotatably support the carrier  682 . The fourth and fifth bearing assemblies  114 ,  116  can be axially located downstream of the gear train  68 . 
     One or more portions of the clutch assembly  117  can be located between the fourth and fifth bearing assemblies  114 ,  116 . However, it is contemplated that one or more portions of the clutch assembly  117  can located upstream of the fourth bearing assembly  114  or downstream of the fifth bearing assembly  116 . The clutch assembly  117  can selectively engage the carrier  682  and the output shaft  80  or output arm  118 . The fourth and fifth bearing assemblies  114 ,  116  can provide axial or radial stabilization for the clutch assembly  117 . 
     The output arm  118  can be selectively coupled to the carrier  682  via the clutch assembly  117 . The clutch assembly  117  is schematically illustrated and any number of assemblies (not shown) or selectable coupling devices or techniques (not shown) are contemplated at the interface of the carrier  682  and the output arm  118  or output shaft  80 . 
     As illustrated by way of non-limiting example, the fourth and fifth bearing assemblies  114 ,  116  are illustrated as rotatably supporting the downstream carrier portion  683  and the output arm  118 . That is, the fourth and fifth bearing assemblies  114 ,  116  can be radially located between the downstream carrier portion  683  and the output arm  118 . 
     The fourth and fifth bearing assemblies  114 ,  116  can include the fourth bearing inner race  120 , the fourth bearing outer race  122 , the fifth bearing inner race  124  and the fifth bearing outer race  126 , with rollers located between the corresponding races. As illustrated, the fourth and fifth bearing inner races  120 ,  124  can rotate with the downstream carrier portion  683 . The fourth and fifth bearing outer races  122 ,  126  can rotate with the output arm  118 . A fourth radial distance  728  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fourth bearing inner race  120 . A fifth radial distance  730  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fifth bearing inner race  124 . 
     As illustrated, by way of non-limiting example, the fourth and fifth radial distance  728 ,  730  can be equal. However, it is contemplated that the fourth radial distance  728  can be greater than or less than the fifth radial distance  730 . 
     The fourth and fifth radial distances  728 ,  730  can be greater than the first radial distance  694  or the second radial distance  700  and less than the third radial distance  712 . However, any combination of greater than, less than, or equal to among the first, second, third, fourth, and fifth radial distances  694 ,  700 ,  712 ,  728 ,  730  is contemplated. 
     The fifth bearing assembly  116  can preload or a reduce forces on the fourth bearing assembly  114 . Further, the fourth and fifth bearing assemblies  114 ,  116  can provide radial alignment and stability to the output shaft  80  about the axis  62 . The axial spacing between the fourth and fifth bearing assemblies  114 ,  116  provides radial support for the carrier  682 . Additionally, or alternatively, the fourth and fifth bearing assemblies  114 ,  116  can provide axial or radial support for the clutch assembly  117 . 
     A drive preload bearing or sixth bearing assembly  632  can be included in the air turbine starter  610 . The sixth bearing assembly  632  can rotatably support the output arm  118 . As illustrated by way of non-limiting example, the sixth bearing assembly  632  is illustrated as rotatably supporting the output arm  118  relative to a third portion  734  of the housing  30 . The third portion  734  of the housing  30  an be a protrusion, extension, or additional structure(s) coupled to or formed with the housing  30 . That is, the sixth bearing assembly  632  can be radially located between the output arm  118  and the third portion  734  of the housing  30 . The sixth bearing assembly  632  can be circumscribed by the housing  30  and rotationally support the output arm  118  relative to the housing  30 . 
     The sixth bearing assembly  632  can include the sixth bearing inner race  636  and the sixth bearing outer race  638 , with rollers located between the races. As illustrated, the sixth bearing inner race  636  can rotate with the output arm  118 . The sixth bearing outer races  638  can be fixed relative the housing  30 . A sixth radial distance  740  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the sixth bearing inner race  636 . As illustrated, by way of non-limiting example, the sixth radial distance  740  can be greater than the first, second, fourth, and fifth radial distances  694 ,  700 ,  728 ,  730 , and less than the third radial distance  712 , however, any combination is contemplated. 
     The sixth bearing assembly  632  can be axially located downstream of the gear train  68 . The sixth bearing assembly  632  can provide support provided to the carrier  682  to reduce vibrations of the carrier  682 . While illustrated with six bearing assemblies, it is contemplated that the gearbox section  46  and the drive section  48  of the air turbine starter  610  can include any number of bearing assemblies with any number or style of rollers. 
       FIG.  6    is still yet another example of an air turbine starter  810 . The air turbine starter  810  is similar to the air turbine starter  10 ,  210 ,  410 ,  610  therefore, like parts will be identified with like numerals further increased by 200, with it being understood that the description of the like parts of the air turbine starter  10 ,  210 ,  410 ,  610  apply to the air turbine starter  810 , unless otherwise noted. 
     Generally, the air turbine starter  810  includes the housing  30  defining the interior  28  having the primary inlet  32  and the primary outlet  34 . The primary air flow path  36 , illustrated schematically with an arrow, extends between the primary inlet  32  and the primary outlet  34  for communicating a flow of fluid, including, but not limited to gas, compressed air, or the like, there through. The primary outlet  34  can include the plurality of circumferentially arranged openings  38  in the peripheral wall  40  of the housing  30 . In this configuration, the primary inlet  32  is an axial inlet and the primary outlet  34  is a radial or circumferential outlet alone the periphery of the housing  30 . 
     The housing  30  can include, in an axial series arrangement, the inlet turbine section  44 , the gearbox section  46 , and the drive section  48 . The seal structure  56  can be coupled to or unitarily formed with the housing  30 . It is contemplated that the seal structure  56  can divide the interior  28  into the inlet turbine section  44  and the gearbox section  46 . 
     The inlet turbine section  44  can include the primary inlet  32 , stationary portions  52 , the turbine  54 , the primary outlet  34 , and at least a portion of the seal structure  56 . The stationary portions  52  can guide air from the primary inlet  32  to the turbine  54  by defining at least a portion of the primary air flow path  36 . 
     The turbine  54  can include the disc or rotor  58  and the plurality of circumferentially spaced blades  60 . The turbine  54 , the rotor  58 , and the plurality of circumferentially spaced blades  60  can rotate about the centerline or axis of rotation  62 . 
     The turbine  54  can further include the drive shaft  66 . The drive shaft  66  can be coupled to or is unitarily formed with the rotor  58  of the turbine  54  allowing for the transfer of energy from air in the primary air flow path  36  to mechanical power. The drive shaft  66  can extend through at least a portion of the inlet turbine section  44  or the gearbox section  46 . 
     The seal structure  56  can define a portion of the primary air flow path  36 . By way non-limiting example, the forward wall  70  of the seal structure  56  can guide air from the turbine  54  to the primary outlet  34 . The seal structure  56  can include the structural wall  57  that bears the seal  59 . The seal  59  can be proved between the structural wall  57  and the drive shaft  66 . 
     The rear wall  84  and a central wall  886  of the seal structure  56  can define a portion of the first cavity  78 . The first cavity  78  can be a wet portion of the housing  30 . That is, the turbine thrust bearing or first bearing assembly  74  or a turbine pre-load bearing or second bearing assembly  876  can be lubricated with a grease or oil in the first cavity  78  of the housing  30 . The first cavity  78  is a portion in the housing  30  that is exposed to grease, oil, or other know coolants or liquids. 
     By way of non-limiting example, the drive shaft  66  can couple the turbine  54  to one or more gears or clutch assemblies, such as the gear train  68 , in the gearbox section  46 . The gearbox section  46  can include at least the gear box  72  that can include the gear train  68 , the first bearing assembly  74 , the second bearing assembly  876 , the first cavity  78 , and the output shaft  80 . The gear box  72  can contain the gear train  68  that couples the drive shaft  66  to the output shaft  80 , so that when driven by the drive shaft  66 , the gear train  68  can transfer mechanical power to the output shaft  80 . The gear train  68  can, for example, be a planetary gear system with a sun gear, a ring gear, and planet gears, which are supported by a carrier  882 . The carrier  882  extends axially from the gear train  68  in the downstream direction towards the output shaft  80 . Any gear train  68  having the carrier  882  or similar structure that operably couples the drive shaft  66  to the output shaft  80  is contemplated. 
     The first bearing assembly  74  or the second bearing assembly  876  can rotationally support the drive shaft  66  to one of the housing  30  or seal structure  56 . As illustrated, by way of non-limiting example, the first bearing assembly  74  and the second bearing assembly  876  are positioned between a first portion  888  of the central wall  886  of the seal structure  56  and the drive shaft  66 . That is, the first bearing assembly  74  and the second bearing assembly  876  can be circumscribed by the first portion  888  of the seal structure  56  where the first bearing assembly  74  and the second bearing assembly  876  rotatably supports the drive shaft  66  relative to the seal structure  56 . 
     The first bearing assembly  74  can include the first bearing inner race  90  and the first bearing outer race  92 , with rollers located between the races. The first bearing inner race  90  can rotate with the drive shaft  66 , while the first bearing outer races  92  can be fixed relative the seal structure  56  or the housing  30 . A first radial distance  894  can be defined as the perpendicular distance from the axis of rotation  62  the first inner portion or the first bearing inner race  90 . 
     The second bearing assembly  876  can include a second bearing inner race  896  and a second bearing outer race  898 , with rollers located between the races. The second bearing inner race  896  can rotate with the drive shaft  66 , while the second bearing outer races  898  can be fixed relative the seal structure  56  or the housing  30 . A second radial distance  900  can be defined as the perpendicular distance from the axis of rotation  62  the second inner portion or the second bearing inner race  896 . 
     Axially, the first and second bearing assemblies  74 ,  876  can be located between the rotor  58  and the gear train  68 . That is, the first bearing assembly  74  and second bearing assembly  876  can be downstream of the rotor  58  and upstream of the gear box  72  or gear train  68 . It is contemplated that the first bearing assembly  74  and the second bearing assembly  876  are fluidly coupled to the first cavity  78 . It is further contemplated that the first bearing assembly  74  or the second bearing assembly  876  can be lubricated using any number of systems. 
     The carrier thrust bearing or third bearing assembly  102  can be included in the air turbine starter  810 . The third bearing assembly  102  can rotatably support the carrier  882 . As illustrated by way of non-limiting example, the third bearing assembly  102  is illustrated as rotatably supporting the carrier  882  relative to a second portion  904  of the housing  30 . That is, the third bearing assembly  102  can be radially located between the carrier  882  and the second portion  904  the housing  30 . 
     The third bearing assembly  102  can include the third bearing inner race  108  and the third bearing outer race  110 , with rollers located between the races. As illustrated, the third bearing inner race  108  can rotate with the carrier  882 . The third bearing outer races  110  can be fixed relative the housing  30  at the second position  904 . A third radial distance  912  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the third bearing inner race  108 . The third radial distance  912  can be greater than the first radial distance  894  or the second radial distance  900 . However, it is contemplated that the third radial distance  912  can be less than or equal to the first radial distance  894  or the second radial distance  900 . 
     The third bearing assembly  102  can be axially located downstream of the gear train  68 . It is contemplated that the third bearing assembly  102  is fluidly coupled to the first cavity  78 . Additionally, or alternatively, it is contemplated that the third bearing assembly  102  can be lubricated using any number of systems. While illustrated as a single roller, the third bearing assembly  102  can include any number or style of rollers. The third bearing assembly  102  can help center or axially locate at least a portion of the gear box  72 . 
     The clutch thrust bearing or fourth bearing assembly  114  and the clutch preload bearing or fifth bearing assembly  116  can be included in the air turbine starter  810 . The fourth and fifth bearing assemblies  114 ,  116  can rotatably support the carrier  882  and a portion of an output arm  718 , where the output arm  718  can couple to an output shaft  880 . The fourth and fifth bearing assemblies  114 ,  116  can be axially located downstream of the gear train  68 . 
     One or more portions of the clutch assembly  117  can be located between the fourth and fifth bearing assemblies  114 ,  116 . However, it is contemplated that one or more portions of the clutch assembly  117  can located upstream of the fourth bearing assembly  114  or downstream of the fifth bearing assembly  116 . The clutch assembly  117  can selectively engage the carrier  882  and the output arm  718  or the output shaft  880 . The fourth and fifth bearing assemblies  114 ,  116  can provide axial or radial stabilization for the clutch assembly  117 . 
     The output arm  718  can be selectively coupled to the carrier  882 . That is, any number of assemblies (not shown) or selectable coupling devices or techniques (not shown) are contemplated at the interface of the carrier  882  and the output arm  718  or output shaft  880 . 
     As illustrated by way of non-limiting example, the fourth and fifth bearing assemblies  114 ,  116  are illustrated as rotatably supporting the carrier  882  and the output arm  718 . That is, the fourth and fifth bearing assemblies  114 ,  116  can be radially located between the carrier  882  and the output arm  718 . 
     The fourth and fifth bearing assemblies  114 ,  116  can include the fourth bearing inner race  120 , the fourth bearing outer race  122 , the fifth bearing inner race  124  and the fifth bearing outer race  126 , with rollers located between the corresponding races. As illustrated, the fourth and fifth bearing inner races  120 ,  124  can rotate with the carrier  882 . The fourth and fifth bearing outer races  122 ,  126  can rotate with the output arm  718 . A fourth radial distance  928  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fourth bearing inner race  120 . A fifth radial distance  930  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the fifth bearing inner race  124 . 
     As illustrated, by way of non-limiting example, the fourth and fifth radial distance  928 ,  930  can be equal. However, it is contemplated that the fourth radial distance  928  can be greater than or less than the fifth radial distance  930 . 
     The fourth and fifth radial distances  928 ,  930  can be greater than a first radial distance  894  or a second radial distance  900  and less than the third radial distance  912 . However, any combination of greater than, less than, or equal to among the first, second, third, fourth, and fifth radial distances  894 ,  900 ,  912 ,  928 ,  930  is contemplated. 
     The fifth bearing assembly  116  can preload or a reduce forces on the fourth bearing assembly  114 . 
     The drive preload bearing or sixth bearing assembly  932  can be included in the air turbine starter  810 . The sixth bearing assembly  932  can rotatably support the output arm  718 . As illustrated by way of non-limiting example, the sixth bearing assembly  932  is illustrated as rotatably supporting the output arm  718  relative to a third portion  934  of the housing  30 . The third portion  934  of the housing  30  an be a protrusion, extension, or additional structure(s) coupled to or formed with the housing  30 . That is, the sixth bearing assembly  932  can be radially located between the output arm  718  and the third portion  934  of the housing  30 . The sixth bearing assembly  932  can be circumscribed by the housing  30  and rotationally support the output arm  718  relative to the housing  30 . 
     The sixth bearing assembly  932  can include a sixth bearing inner race  936  and a sixth bearing outer race  938 , with rollers located between the races. As illustrated, the sixth bearing inner race  936  can rotate with the output arm  718 . The sixth bearing outer races  938  can be fixed relative the housing  30 . A sixth radial distance  740  can be defined as the perpendicular distance from the axis of rotation  62  to an inner portion or the sixth bearing inner race  936 . As illustrated, by way of non-limiting example, the sixth radial distance  740  can be greater than the first, second, fourth, and fifth radial distances  894 ,  900 ,  928 ,  930 , and less than the third radial distance  912 , however, any combination is contemplated. 
     The sixth bearing assembly  932  can be axially located downstream of the gear train  68 . While illustrated with six bearing assemblies, it is contemplated that the gearbox section  46  and the drive section  48  of the air turbine starter  810  can include any number of bearing assemblies with any number or style of rollers. 
     The sixth bearing assembly  932  can axially align with at least a portion of the fifth bearing assembly  116 . That is, at least a portion of the sixth bearing assembly  932  can circumscribe at least a portion of the fifth bearing assembly  116 . The axial overlap can provide increased stability in the axial direction for at least the output arm  718 . The axial overlap can provide radial stability to the output shaft  880 . Further, the sixth bearing assembly  932  can be part of a combination of bearing assemblies that center the gear box  72 . 
     Benefits associated with aspects of the disclosure herein include a reduced load to the first bearing assembly or thrust bearing. The second bearing assembly, especially when located downstream of the gear train, can help to radially align the drive shaft. The first and second bearing assemblies provide a saddle mount for the drive shaft; that is, there is at least one bearing rotatably supporting the drive shaft on each side of the gear box. This results in better alignment of the drive shaft in the first bearing assembly or thrust bearing, can reduce the axial load, and therefore the temperature of the first bearing assembly. The temperature of the bearings is often one of the limiting factors in determining the length of time the air turbine starter can operate before requiring cool down time. Aspects of the present disclosure reduce the temperature of the bearings during motoring, which increases the amount of time the air turbine starter can operate. Longer operation of the air turbine starter allows for multiple attempts at firing the turbine engine from the air turbine starter before requiring a cool down period for the air turbine starter. The saddle mount can also provide better alignment of the drive shaft in the gear box. 
     Additional benefits include a longer part life due to increased cooling of the parts. Aspects of the present disclosure provide a reduced thermal load on the first bearing assembly or thrust bearing of the air turbine starter. 
     Further, benefits include improved lubrication of the first bearing assembly or thrust bearing as lubrication from the first cavity can easily enter or splash the first bearing assembly or thrust bearing of the air turbine starter. 
     Further, additional benefits can include a decrease in the size of the air turbine starter. The location of the bearing assemblies can allow for a smaller air turbine starter. Specifically, when only one bearing assembly is required upstream of the gear box, this allows for the diameter and/or the axial length of the air turbine starter to be smaller than a configuration with two bearing assemblies upstream of the gear box. 
     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 devices or systems and performing any incorporated methods. 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 with insubstantial differences from the literal languages of the claims. 
     Further aspects of the disclosure are provided by the subject matter of the following clauses: 
     1. An air turbine starter comprising a housing having a primary inlet and primary outlet to define a primary air flow path from the primary inlet to the primary outlet, a gear box located within a gearbox section and having a drive shaft and an output shaft, with a gear train, including a carrier, operably coupling the drive shaft and the output shaft, a turbine having a rotor coupled to the drive shaft and a plurality of circumferentially spaced blades extending from the rotor, a first bearing assembly rotatably supporting the drive shaft relative to the housing, and a second bearing assembly rotatably supporting at least one of the carrier or the output shaft relative to at least one of the drive shaft or housing. 
     2. The air turbine starter of any of the preceding clauses, wherein the first bearing assembly is axially located between the rotor and the gear train. 
     3. The air turbine starter of any of the preceding clauses, wherein the second bearing assembly is axially located downstream of the gear box. 
     4. The air turbine starter of any of the preceding clauses, wherein the first bearing assembly is located at a first radial distance and the second bearing assembly is located at a second radial distance, wherein the first radial distance is greater than or equal to the second radial distance. 
     5. The air turbine starter of any of the preceding clauses further including a third bearing assembly configured to rotatably support the carrier and located between the carrier and a second portion of the housing. 
     6. The air turbine starter of any of the preceding clauses, wherein the third bearing assembly is located at a third radial distance that is greater than the second radial distance. 
     7. The air turbine starter of any of the preceding clauses wherein the third bearing assembly is axially located downstream of the gear train. 
     8. The air turbine starter of any of the preceding clauses, wherein at least a portion of the third bearing assembly circumscribes at least a portion of the second bearing assembly. 
     9. The air turbine starter of any of the preceding clauses, wherein the third bearing assembly is axially located between the rotor and the gear train. 
     10. The air turbine starter of any of the preceding clauses, wherein the second bearing assembly is axially located between the rotor and the gear train. 
     11. The air turbine starter of any of the preceding clauses further including a third bearing assembly configured to rotatably support the carrier and located between the carrier and a second portion of the housing. 
     12. The air turbine starter of any of the preceding clauses, wherein the third bearing assembly is located at a third radial distance and the second bearing assembly is located at a second radial distance that is less than the third radial distance. 
     13. The air turbine starter of any of the preceding clauses further comprising a seal dividing an interior of the housing into a turbine section and the gearbox section. 
     14. An air turbine starter comprising a housing defining an interior having a primary inlet and a primary outlet to define a primary air flow path from the primary inlet to the primary outlet, a turbine located in the interior that includes a rotor with a plurality of circumferentially spaced blades that extend into the primary air flow path, a drive shaft operably coupled with the turbine, a gear box located in the interior and including a gear train coupled to the drive shaft, a first bearing assembly configured to rotatably support the drive shaft and located between the drive shaft and a first portion of the housing, a second bearing assembly configured to rotatably support a carrier coupled to the gear train, and a third bearing assembly configured to rotatably support the carrier and located between the carrier and a second portion of the housing. 
     15. The air turbine starter of any of the preceding clauses, wherein the first bearing assembly is axially located between the rotor and the gear train. 
     16. The air turbine starter of any of the preceding clauses, wherein the second bearing assembly is axially located downstream of the gear box. 
     17. The air turbine starter of any of the preceding clauses further including a sixth bearing assembly configured to rotatably support an output arm or output shaft relative to a third portion of the housing. 
     18. The air turbine starter of any of the preceding clauses, wherein at least a portion of the third bearing assembly circumscribes at least a portion of the second bearing assembly. 
     19. The air turbine starter of any of the preceding clauses, wherein the first bearing assembly is located at a first radial distance and the second bearing assembly is located at a second radial distance, wherein the first radial distance is greater than or equal to the second radial distance. 
     20. The air turbine starter of any of the preceding clauses, wherein the second bearing assembly is located at a second radial distance and the third bearing assembly is located at a third radial distance, wherein the second radial distance is less than the third radial distance.