Patent Publication Number: US-2018029415-A1

Title: Axle assembly having a wheel mount disposed on a planet carrier

Description:
TECHNICAL FIELD 
     This disclosure relates to an axle assembly having a wheel mount disposed on a planet carrier of a planetary gear set. 
     BACKGROUND 
     A drive axle having a planetary wheel end is disclosed in U.S. Pat. No. 4,646,880. 
     SUMMARY 
     In at least one embodiment, an axle assembly is provided. The axle assembly may include an axle housing, a wheel bearing cage, a planetary gear set, a wheel mount, one or more dowels, and one or more fasteners. The wheel bearing cage may be fixedly positioned with respect to the axle housing. The planetary gear set may be received in the wheel bearing cage. The planetary gear set may have a planet carrier that may rotate about an axis. The wheel mount may be disposed on the planet carrier and may be configured to facilitate mounting of a wheel. One or more dowels may be received in the wheel mount and the planet carrier. One or more fasteners may couple the wheel mount to the planet carrier. 
     In at least one embodiment, an axle assembly is provided. The axle assembly may include an axle housing, a wheel bearing cage, a planetary gear set, a wheel mount, one or more dowels, and a preload bolt. The wheel bearing cage may be fixedly positioned with respect to the axle housing. The planetary gear set may be received in the wheel bearing cage. The planetary gear set may have a planet carrier that may rotate about an axis. The wheel mount may be disposed on the planet carrier and may be configured to facilitate mounting of a wheel. The preload bolt may extend along the axis and may couple the wheel mount to the planet carrier. One or more dowels may be arranged around the preload bolt and may be received in the wheel mount and the planet carrier. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary axle assembly. 
         FIG. 2  is a section view of the axle assembly along section line  2 - 2 . 
         FIG. 3  is an exploded view of a portion of the axle assembly of  FIG. 1 . 
         FIGS. 4 and 5  are section views showing alternative configurations for attaching a wheel mount to a planet carrier of the axle assembly. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Referring to  FIG. 1 , an example of an axle assembly  10  is shown. The axle assembly  10  may be provided with a motor vehicle like a truck, bus, construction equipment, farm equipment, mining equipment, military transport or weaponry vehicle, or cargo loading equipment for land, air, or marine vessels. The motor vehicle may include a trailer for transporting cargo in one or more embodiments. 
     The axle assembly  10  may be a drive axle that may be part of a vehicle drivetrain that may provide torque to one or more traction wheel assemblies, such as a wheel assembly that may include a tire  12  mounted on a wheel  14  as is best shown in  FIG. 2 . The vehicle drivetrain may include a power source, such as a motor, that may be operatively connected to an input  16  of the axle assembly  10 . The input  16  may be operatively connected to a differential of the axle assembly  10 , which in turn may be operatively connected to a wheel assembly via an axle shaft. 
     One or more axle assemblies  10  may be provided with the vehicle. For example, the axle assembly  10  may be part of a tandem axle configuration or multi-axle configuration that may include a plurality of axle assemblies that may be connected in series. Alternately, an axle assembly  10  may not be connected in series with another axle assembly in one or more embodiments. Referring to  FIGS. 1 and 2 , the axle assembly  10  may include a housing assembly  20 , an axle shaft  22 , a planetary gear set  24 , a wheel mount  26 , a first roller bearing assembly  28 , a second roller bearing assembly  30 , a preload bolt  32 , a locking fastener  34 , and a brake assembly  36 . 
     The housing assembly  20  may receive various components of the axle assembly  10 . For example, components and subassemblies like the axle shaft  22 , planetary gear set  24 , wheel mount  26 , first roller bearing assembly  28 , second roller bearing assembly  30 , and brake assembly  36  may be disposed inside the housing assembly  20 . In addition, the housing assembly  20  may facilitate mounting of the axle assembly  10  to the vehicle. In at least one embodiment, the housing assembly  20  may include an axle housing  40 , a brake housing  42 , and a wheel bearing cage  44 . 
     The axle housing  40  may be disposed proximate the center of the housing assembly  20 . For example, the axle housing  40  may extend between brake housings  42  that may be disposed near opposite ends of the axle assembly  10 . The axle housing  40  may be configured to receive a differential and the axle shafts  22  that may extend from the differential. 
     Referring to  FIGS. 1 and 2 , the brake housing  42  may be disposed between the axle housing  40  and the wheel bearing cage  44 . The brake housing  42  may be assembled to the axle housing  40  and the wheel bearing cage  44  with one or more fasteners, such as bolts, that may extend through the corresponding fastener holes in the axle housing  40 , brake housing  42 , and wheel bearing cage  44 . As such, the axle housing  40 , brake housing  42 , and wheel bearing cage  44  may be fixedly positioned with respect to each other. 
     The wheel bearing cage  44  may be disposed on the brake housing  42  and may be disposed at an end of the housing assembly  20 . As is best shown in  FIG. 2 , the wheel bearing cage  44  may extend around an axis  50  and may have a tapered exterior surface that may become narrower or may extend closer to the axis  50  in a direction that extends away from the brake housing  42 . The wheel bearing cage  44  may receive and may facilitate mounting of the first roller bearing assembly  28  and the second roller bearing assembly  30 . In addition, the wheel bearing cage  44  may define a cavity that may receive a planet carrier of the planetary gear set  24  and a tubular portion of the wheel mount  26  as will be discussed in more detail below. 
     Referring to  FIGS. 2 and 3 , the axle shaft  22  may transmit torque from the differential to a planetary gear set  24 . For example, the axle shaft  22  may extend along and may be rotated about an axis  50  by the differential. The axle shaft  22  may have a first end and a second end. The first end may be operatively connected to the planetary gear set  24 . The second end may be disposed opposite the first end and may be operatively connected to the differential. 
     The planetary gear set  24  may be disposed in the housing assembly  20 . For instance, the planetary gear set  24  may be received in the wheel bearing cage  44 . The planetary gear set  24  may be configured to provide a desired gear reduction ratio and increase torque provided to a wheel  14 . In at least one embodiment, the planetary gear set  24  may include a sun gear  60 , a plurality of planet pinions  62 , a ring gear  64 , and a planet carrier  66 . 
     The sun gear  60  may be disposed proximate the center of the planetary gear set  24 . The sun gear  60  may also be disposed on the axle shaft  22  such that the sun gear  60  may rotate about the axis  50  with the axle shaft  22 . For instance, the sun gear  60  may have a hole that may receive the axle shaft  22 . One or more fasteners, such as snap rings, may be provided to secure the sun gear  60  to the axle shaft  22  and limit movement of the sun gear  60  in an axial direction or along the axis  50 . The sun gear  60  may have a set of teeth that may engage and mesh with the planet pinions  62 . 
     The planet pinions  62  may be spaced apart from each other and may be rotatably disposed between the sun gear  60  and the ring gear  64 . Each planet pinion  62  may have a planet pinion hole and a set of teeth. The set of teeth may be disposed opposite the planet pinion hole on an exterior surface or outside diameter of the planet pinion  62 . The set of teeth may mesh with teeth on the sun gear  60  and teeth on the ring gear  64 . Each planet pinion  62  may be configured to rotate about a different planet pinion axis. The planet pinion axes may extend substantially parallel to the axis  50 . 
     The ring gear  64  may extend around the axis  50  and may be disposed between the wheel bearing cage  44  and the planet pinions  62 . In addition, the ring gear  64  may include a plurality of teeth that may extend toward the axis  50  and may mesh with teeth on the planet pinions  62 . The ring gear  64  may be fixedly positioned with respect to the housing assembly  20  and the axis  50 . For example, the ring gear  64  may be disposed in the housing assembly  20  such that an outside circumference of the ring gear  64  may be disposed proximate and may engage the wheel bearing cage  44 . The ring gear  64  may be disposed between the brake housing  42  and the wheel bearing cage  44  such that the brake housing  42  and the wheel bearing cage  44  may cooperate to inhibit axial movement of the ring gear  64 . 
     The planet carrier  66  may support to the planet pinions  62  and may be configured to rotate about the axis  50 . The planet carrier  66  may be provided in various configurations. In at least one embodiment, the planet carrier  66  may have a plurality of hubs  70 , one or more dowel holes  72 , and one or more fastener holes  74 . 
     Each hub  70  may be received in corresponding planet pinion hole to help support and position a corresponding planet pinion  62 . A roller bearing may be disposed in the planet pinion hole between a hub  70  and a corresponding planet pinion  62  to facilitate rotation of the planet pinion  62  with respect to the hub  70 . 
     One or more dowel holes  72  may be provided in the planet carrier  66 . In  FIG. 3 , four dowel holes  72  are shown; however, it is contemplated that a greater or lesser number of dowel holes  72  may be provided. The dowel holes  72  may be spaced apart from each other and may be arranged around the axis  50 . In addition, the dowel holes  72  may be disposed at a generally equal radial distance from the axis  50 . Each dowel hole  72  may extend from an end or end surface  76  of the planet carrier  66  toward the axle housing  40  or to the right from the perspective shown in  FIG. 2 . Each dowel hole  72  may extend along and may be centered about a dowel hole axis  80 . The dowel hole axis  80  may extend substantially parallel to the axis  50 . 
     Each dowel hole  72  may be configured to receive a dowel  100  that may help position the wheel mount  26  on the planet carrier  66  and help inhibit rotation or movement of the wheel mount  26  with respect to the planet carrier  66 . The dowel  100  may be a solid dowel or a hollow dowel and may help transmit high torque loads between the planet carrier  66  and the wheel mount  26 . Each dowel  100  may have a generally cylindrical configuration and may extend along a dowel axis  102  that may be coaxially disposed with the dowel hole axis  80 . 
     At least one fastener hole  74  may be provided in the planet carrier  66 . In  FIGS. 2 and 3 , one fastener hole  74  is provided that may extend along the axis  50  from the end surface  76  toward the axle shaft  22 . The fastener hole  74  may be threaded or have one or more threads that may mate with a threaded portion of the preload bolt  32  as will be discussed in more detail below. 
     Referring to  FIGS. 2 and 3 , the wheel mount  26  may facilitate mounting of a wheel  14  and may be disposed on and may engage the planet carrier  66 . In addition, the wheel mount  26  may be partially received in the wheel bearing cage  44  such that the wheel mount  26  may be spaced apart from and may not engage the wheel bearing cage  44 . In at least one embodiment, the wheel mount  26  may include a tubular portion  110  and a flange portion  112 . 
     The tubular portion  110  may be at least partially disposed in the housing assembly  20 . The tubular portion  110  may extend around the axis  50  and may at least partially define a wheel mount hole  120  and one or more dowel openings  122 . 
     The wheel mount hole  120  may extend through the wheel mount  26  and may not receive the planet carrier  66  in one or more embodiments. The tubular portion  110  may have an exterior surface that may be disposed opposite the wheel mount hole  120 . The exterior surface may support the first roller bearing assembly  28  and the second roller bearing assembly  30 . As is best shown in  FIG. 2 , the tubular portion  110  may have a first inner surface  124  that may extend around the axis  50 . The first inner surface  124  may at least partially define the wheel mount hole  120  and may be spaced apart from and may not engage the preload bolt  32 . 
     One or more dowel openings  122  may be arranged around the axis  50 . Each dowel opening  122  may be aligned with a corresponding dowel hole  72  in the planet carrier  66 . As such, a dowel opening  122  may be coaxially disposed with a dowel hole  72 , dowel hole axis  80 , and a dowel  100 . Each dowel opening  122  may extend from an end of the tubular portion  110  toward the flange portion  112  or to the left from the perspective shown in  FIG. 2 . The dowel opening  122  may receive and engage a dowel  100 . Moreover, the dowel opening  122  may be a blind hole that may engage an end of the dowel  100  to limit axial movement of the dowel  100  in one or more embodiments. 
     The flange portion  112  may be disposed outside of the housing assembly  20  and may be integrally formed with the tubular portion  110 . The flange portion  112  may be disposed at an end of the tubular portion  110  and may extend away from the axis  50 . The flange portion  112  may be spaced apart from and may not engage the housing assembly  20 . For instance, a gap may be provided between the flange portion  112  and the wheel bearing cage  44  to permit rotational movement of the wheel mount  26  and to facilitate application of a preload force on the first roller bearing assembly  28 , the second roller bearing assembly  30 , or both as will be discussed in more detail below. 
     The flange portion  112  may at least partially define the wheel mount hole  120  and may receive the preload bolt  32 . In at least one embodiment, the flange portion  112  may include a second inner surface  126 , a third inner surface  128 , a step surface  130 , a locking fastener opening  132 , a rim  134 , and a plurality of wheel stud holes  136 . 
     The second inner surface  126  may extend around the axis  50  and may at least partially define the wheel mount hole  120 . The second inner surface  126  may be axially positioned between the first inner surface  124  and the third inner surface  128 . The second inner surface  126  may be disposed further from the axis  50  than the first inner surface  124 . 
     The third inner surface  128  may extend around the axis  50  and may at least partially define the wheel mount hole  120 . The third inner surface  128  may be disposed further from the axis  50  than the second inner surface  126 . As such, the third inner surface  128  may have a larger diameter than the second inner surface  126 . 
     The step surface  130  may extend between the second inner surface  126  and the third inner surface  128 . For example, the step surface  130  may extend from the second inner surface  126  to the third inner surface  128 . In addition, the step surface  130  may be disposed substantially perpendicular to the axis  50  in one or more embodiments. 
     One or more locking fastener openings  132  may be provided to receive a locking fastener  34 . The locking fastener opening  132  may be disposed in various locations, such as in the step surface  130  or the third inner surface  128 . The locking fastener opening  132  may be a threaded hole that may receive and retain the locking fastener  34 . 
     The rim  134  may be disposed opposite the wheel mount hole  120  and may extend away from the axis  50 . The rim  134  may be disposed opposite the first inner surface  124  and may engage an inner race of the first roller bearing assembly  28 . 
     The wheel stud holes  136  may facilitate mounting of a wheel  14  to the wheel mount  26 . The wheel stud holes  136  may be through holes that may be arranged around the axis  50 . Each wheel stud hole  136  may receive a fastener, such as a wheel stud  140  that may extend through a corresponding hole on the wheel  14 . A lug nut  142  may be attached to the wheel stud  140  to secure the wheel  14  to the wheel mount  26 . 
     Referring primarily to  FIG. 2 , the first roller bearing assembly  28  may be disposed in the housing assembly  20  and may rotatably support the wheel mount  26 . For example, the first roller bearing assembly  28  may extend between the wheel mount  26  and the wheel bearing cage  44  and may be axially positioned near an end of the wheel bearing cage  44  that may be disposed opposite the brake housing  42 . The first roller bearing assembly  28  may include a plurality of rolling elements  150 , such as balls or rollers, that may be disposed between a first inner race  152  and a first outer race  154 . The first inner race  152  may be disposed proximate and may engage the wheel mount  26 . In addition, the first inner race  152  may be disposed proximate and may engage the rim  134  of the wheel mount  26  such that the wheel mount  26  may exert a preload force against the first inner race  152  when the preload bolt  32  is tightened as will be discussed in more detail below. The first outer race  154  may be disposed proximate and may engage the wheel bearing cage  44  such that the wheel bearing cage  44  may inhibit movement of the first outer race  154  in an axial direction that may extend toward the axle housing  40 , or to the right from the perspective shown in  FIG. 2 . 
     The second roller bearing assembly  30  may be disposed in the housing assembly  20  and may also rotatably support the wheel mount  26 . For example, the second roller bearing assembly  30  may extend between the wheel mount  26  and the wheel bearing cage  44  and may be axially positioned between the first roller bearing assembly  28  and the planet carrier  66 . The second roller bearing assembly  30  may include a plurality of rolling elements  160 , such as balls or rollers, that may be disposed between a second inner race  162  and a second outer race  164 . The second inner race  162  may be disposed on and may engage the wheel mount  26  and the planet carrier  66 . As such, the planet carrier  66  may help exert a preload force against the second inner race  162  when the preload bolt  32  is tightened. The second outer race  164  may be disposed proximate and may engage the wheel bearing cage  44  such that the wheel bearing cage  44  may inhibit movement of the second outer race  164  in an axial direction that may extend away from the axle housing  40 , or to the left from the perspective shown in  FIG. 2 . 
     Optionally, a bearing spacer  166  may be provided between the first roller bearing assembly  28  and the second roller bearing assembly  30 . The bearing spacer  166  may extend from the first inner race  152  to the second inner race  162  to inhibit movement of the first inner race  152  and second inner race  162  with respect to each other. The bearing spacer  166  may be disposed on the tubular portion  110  of the wheel mount  26  and may be configured as a ring that may extend around the tubular portion  110  in one or more embodiments. 
     Referring to  FIG. 3 , the preload bolt  32  may be partially or completely received in the wheel mount hole  120  and may couple the wheel mount  26  to the planet carrier  66 . In at least one embodiment, the preload bolt  32  may have a preload bolt body  170  and a preload bolt flange  172 . 
     The preload bolt body  170  may extend along the axis  50  and may be received in the wheel mount hole  120 . The preload bolt body  170  may have a threaded portion  174  that may be received in the fastener hole  74  of the planet carrier  66 . The threaded portion  174  may have one or more threads that may mate with one or more threads in the fastener hole  74  of the planet carrier  66 . 
     The preload bolt flange  172  may be integrally formed with the preload bolt body  170 . The preload bolt flange  172  may be received in the wheel mount hole  120  may exert force on the wheel mount  26 . For instance, the preload bolt flange  172  may engage and may exert force on the step surface  130  of the wheel mount  26 . In addition, the preload bolt flange  172  may be spaced apart from the third inner surface  128  of the wheel mount  26 . In at least one embodiment, the preload bolt flange  172  may include an engagement feature  180  and a set of preload bolt flange openings  182 . 
     The engagement feature  180  may allow a tool to apply torque to rotate the preload bolt  32  about the axis  50 . The engagement feature  180  may have any suitable configuration, such as a male configuration, female configuration or combinations thereof. In  FIGS. 2 and 3 , the engagement feature  180  has a male configuration that may be received in a tool, such as a socket or wrench. The engagement feature  180  may be at least partially received in a recess  184  in the preload bolt  32 . 
     The set of preload bolt flange openings  182  may extend through the preload bolt flange  172 . The preload bolt flange openings  182  may be arranged around the axis  50  and may be spaced apart from each other. The preload bolt flange openings  182  may have any suitable configuration. In the embodiment shown in  FIG. 3 , the preload bolt flange openings  182  are generally semicircular and extend from an outside circumferential surface of the preload bolt flange  172  toward the axis  50 . Alternatively, the preload bolt flange openings  182  may be configured as through holes that may be completely defined with in the preload bolt flange  172  and may be spaced apart from the outside circumferential surface of the preload bolt flange  172 . 
     A preload bolt seal  186  may be disposed between the preload bolt  32  and the wheel mount  26 . The preload bolt seal  186  may help retain lubricant inside the axle assembly  10  and may inhibit contaminants from entering at least a portion of the wheel mount hole  120 . For example, the preload bolt seal  186  may be configured as an O-ring that may extend around the axis  50 . 
     The locking fastener  34  may inhibit rotation of the preload bolt  32  about the axis  50 . For example, the locking fastener  34  may be inserted into or received in a preload bolt flange opening  182  that may be proximately aligned with the locking fastener opening  132  after the preload bolt  32  is tightened to exert a desired preload force on at least one of the first roller bearing assembly  28  and the second roller bearing assembly  30 . As such, the locking fastener  34  may engage the preload bolt  32  and may be coupled to and may engage the wheel mount  26  to inhibit rotation of the preload bolt  32 . The locking fastener  34  may be offset from the axis  50  and may not extend along the axis  50 . The locking fastener  34  may have any suitable configuration. For instance, the locking fastener  34  may be a threaded fastener, such as a bolt or screw. 
     A preload force may be applied to the first roller bearing assembly  28  and/or the second roller bearing assembly  30  by rotating the preload bolt  32 . Tightening the preload bolt  32  into the fastener hole  74  in the planet carrier  66  may cause the preload bolt flange  172  to exert force on the wheel mount  26  in an axial direction that may extend to the right from the perspective shown in  FIG. 2 . The rim  134  of the wheel mount  26  may then exert force on the first inner race  152  of the first roller bearing assembly  28  in the same direction. Tightening the preload bolt  32  may also pull the planet carrier  66  in an axial direction toward the wheel mount  26  or to the left from the perspective shown in  FIG. 2 . The planet carrier  66  may then exert force on the second inner race  162  of the second roller bearing assembly  30  in the same direction. As such, the preload bolt  32  may exert a preload force that may bias the first roller bearing assembly  28  toward the second roller bearing assembly  30 . 
     The preload bolt  32  may provide axial flexibility that may allow a more stable preload force to be applied against one or more roller bearing assemblies. For example, the preload bolt  32  may cooperate with the wheel mount  26  and the planet carrier  66  to exert a stable or relatively constant preload force that may accommodate “settling” of the axle assembly  10  due to operation and initial wear. A preload force that remains substantially stable over time may reduce deflection with respect to the axis  50  and may increase operational life of the roller bearings and associated gears of the axle assembly  10 . The preload bolt  32  may also eliminate the need for a separate wheel end cover that may otherwise be provided to cover and seal against the wheel mount  26  to retain lubricant inside the axle assembly  10 . 
     Referring to  FIG. 2 , the brake assembly  36  may be adapted to slow or inhibit rotation of the sun gear  60  and an associated wheel  14  about the axis  50 . The brake assembly  36  may be a wet disc brake assembly that may be disposed inside the housing assembly  20 . In at least one embodiment, the brake assembly  36  may include a disc pack  190 , one or more brake dowels  192 , a piston  194 , one or more shoulder bolts  196 , and at least one biasing member  198 . 
     The disc pack  190  may be received in the brake housing  42 . The disc pack  190  may include one or more friction discs  200  and one or more stationary discs  202 . 
     One or more friction discs  200  may be disposed on the sun gear  60  and may extend away from the axis  50 . The friction discs  200  may have a hole that may receive sun gear  60  such that the friction disc  200  rotates about the axis  50  with the sun gear  60 . 
     One or more stationary discs  202  may be disposed adjacent to a friction disc  200 . The stationary discs  202  may be spaced apart from each other such that a friction disc  200  is disposed between adjacent stationary discs  202 . The stationary discs  202  may extend from the brake housing  42  toward the axis  50  and may not rotate about the axis  50 . The stationary discs  202  may at least partially receive a corresponding brake dowel  192 . 
     One or more brake dowels  192  may extend from the axle housing  40  to the brake housing  42 . The axle housing  40  and the brake housing  42  may cooperate to hold each brake dowel  192  in a fixed position such that the brake dowels  192  may not rotate about the axis  50 . 
     The piston  194  may be received in the brake housing  42  between the planetary gear set  24  and the disc pack  190 . The piston  194  may be configured to move in an axial direction with respect to the brake housing  42  between a retracted position and an extended position. The piston  194  may be actuated from a retracted position to an extended position by pressurized fluid from a pressurized fluid source  210 . In the retracted position, the stationary discs  202  and friction discs  200  may not be deflected or urged against a flange of the axle housing  40 . As such, force may not be exerted by the piston  194  against the disc pack  190  to brake to inhibit rotation of a wheel  14 . In the extended position, the piston  194  may move toward the disc pack  190  and may urge the disc pack  190  toward the flange such that the stationary discs  202  and friction discs  200  may be deflected or urged toward the flange and against each other. As such, the stationary discs  202  and the friction discs  200  may engage each other, resulting in friction that may inhibit rotation of the friction discs  200  about the axis  50  with respect to the stationary discs  202 . The friction discs  200  may then inhibit rotation of the sun gear  60 , axle shaft  22 , planetary gear set  24 , and the wheel mount  26  and its associated wheel  14 . A controller may open one or more valves to permit pressurized fluid to flow from the pressurized fluid source  210  through a fluid passage to actuate the piston  194  in response to a brake command. 
     One or more shoulder bolts  196  may be fixedly disposed on the brake housing  42 . The shoulder bolts  196  may extend through the piston  194 . 
     A biasing member  198  may be disposed on each shoulder bolt  196  between the disc pack  190  and the piston  194 . The biasing member  198  may extend between the piston  194  and the enlarged head of the shoulder bolt  196 . The biasing member  198  may exert a biasing force on the piston  194  that may actuate the piston  194  away from the flange of the axle housing  40  and toward the brake housing  42  (i.e., from the extended position toward the retracted position) when sufficient fluid pressure is not exerted on the opposite side of the piston  194 . As such, the biasing member  198  may bias the piston  194  to the left from the perspective shown in  FIG. 2 . 
     Referring to  FIG. 4 , another configuration for mounting the wheel mount to the planet carrier is shown. This configuration is similar to that shown in  FIG. 2 , but multiple fastener holes  74 ′ may be provided and repositioned on the planet carrier  66  and the wheel mount  26  has one or more fastener openings  220  that receive one or more fasteners  222  that replace the preload bolt  32 . Moreover, the wheel mount  26  may be simplified by omitting features such as the second inner surface  126 , third inner surface  128 , step surface  130 , and locking fastener opening  132 . The locking fastener  34  may also be omitted. 
     One or more fastener holes  74 ′ and fastener openings  220  may be arranged around the axis  50 . Each fastener opening  220  may be aligned with a corresponding fastener hole  74 ′ in the planet carrier  66 . As such, the fastener hole  74 ′ and fastener opening  220  may be coaxially disposed with the fastener  222 . Each fastener hole  74 ′ may be configured as a through hole that may extend through the planet carrier  66 . Each fastener opening  220  may be a blind hole that may be threaded. 
     Each fastener  222  may extend through the fastener hole  74 ′ and a corresponding fastener opening  220  to couple the wheel mount  26  the planet carrier  66 . The fastener  222  may have any suitable configuration. For example, the fastener  222  may be configured as a threaded fastener, such as a bolt. An enlarged head  224  of the fastener  222  may be disposed in a fastener hole  74 ′ while a threaded shaft of the fastener  222  may extend into the fastener hole  74 ′ and mate with corresponding threads of the fastener hole  74 ′. 
     The fastener  222  may extend along a fastener axis  226 . The fastener axis  226  may extend substantially parallel to the axis  50 . However, each fastener  222  may be offset from the axis  50  such that the fastener  222  may not extend along or intersect the axis  50 . The fastener axis  226  may be coplanar with the dowel axis  102  and the axis  50  in one or more embodiments. The fastener  222  may be radially positioned between the dowel  100  and the axis  50  or such that the fastener  222  and fastener axis  226  are disposed closer to the axis  50  than the dowel  100 . As such the fastener  222  may be spaced apart from and may not engage the dowel  100  and a fastener  222  may be disposed between a dowel  100  and the axis  50 . 
     Referring to  FIG. 5 , another configuration for mounting the wheel mount to the planet carrier shown. This configuration is similar to that shown in  FIG. 4 . In this configuration, one or more fasteners  222  extend through the corresponding dowel  100 ′. More specifically, the dowel  100 ′ is a hollow dowel that may have an internal dowel hole  230  and a dowel flange  232 . 
     The internal dowel hole  230  may extend completely through the dowel  100 ′ and may be disposed along and may be centered about the dowel axis  102 ′. The internal dowel hole  230  may receive the fastener  222 . The dowel axis  102 ′ may be coaxially disposed with the fastener axis  226 . 
     The dowel flange  232  may be disposed at a first end of the dowel  100 ′. The dowel flange  232  may extend continuously around the dowel axis  102 ′ and may extend away from the dowel axis  102 ′. For instance, the dowel flange  232  may be disposed substantially perpendicular to the dowel axis  102 ′ in one or more embodiments. The dowel flange  232  may be received in the dowel hole  72  of the planet carrier  66  and may engage the planet carrier  66  to inhibit movement of the dowel  100 ′. As such, the dowel flange  232  may inhibit movement of the dowel  100 ′ toward the wheel mount  26 , or to the left from the perspective shown in  FIG. 5 . 
     The dowel  100 ′ may have a second end that may be disposed opposite the first end and that may be received in the dowel opening  122  of the wheel mount  26 . 
     The enlarged head  224  of the fastener  222  may be disposed on the dowel flange  232 . In addition, the enlarged head  224  may be located outside of the dowel hole  72  between the dowel flange  232  and the planet carrier  66 . The threaded portion of the fastener  222  may be received in the fastener opening  220 , which may be disposed adjacent to the dowel opening  122 . The fastener opening  220  may be coaxially disposed with the dowel opening  122  and may have a smaller diameter than the dowel opening  122  in one or more embodiments. 
     In any configuration, one or more shims  240  may be provided between the wheel mount  26  and the planet carrier  66  to help set the preload force exerted one or more of the roller bearings. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.