Patent Publication Number: US-2022212498-A1

Title: Axle assembly having a drive pinion and a preload nut and a method of assembly

Description:
TECHNICAL FIELD 
     This disclosure relates to an axle assembly having a drive pinion and a preload nut and a method of assembly. 
     BACKGROUND 
     An axle assembly having a drive pinion and a bearing preload element is disclosed in U.S. Pat. No. 10,316,950. 
     SUMMARY 
     In at least one embodiment an axle assembly is provided. The axle assembly may include a drive pinion and a preload nut. The drive pinion may be rotatable about an axis and may include a shaft that extends from a gear. The shaft may have a threaded portion and a recess that is disposed proximate the threaded portion. The preload nut may have a thread that mates with the threaded portion and a deformable ring that is disposed proximate the threaded portion. The deformable ring may engage the shaft inside the recess to inhibit the preload nut from rotating about the axis with respect to the drive pinion. 
     In at least one embodiment a method of assembling an axle assembly is provided. The method may include threading a preload nut onto a threaded portion of a drive pinion such that a deformable ring of the preload nut is disposed outside and extends around at least a portion of a recess in the drive pinion. The deformable ring may be deformed into the recess and into engagement with the drive pinion in the recess to inhibit the preload nut from rotating with respect to the drive pinion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example of an axle assembly. 
         FIG. 2  is a section view of the axle assembly of  FIG. 1  along section line  2 - 2 . 
         FIG. 3  is a magnified view of a portion of  FIG. 2  that shows a drive pinion and a preload nut before the preload nut is fixed to a drive pinion. 
         FIG. 4  is a magnified view of a portion of  FIG. 3 . 
         FIG. 5  is a section view along section line  5 - 5  without bearing assemblies that support the drive pinion. 
         FIG. 6  is a magnified view that shows the preload nut fixed to the drive pinion. 
         FIG. 7  is a section view along section line  7 - 7  and additionally examples of engagement features fixing the preload nut to the drive pinion. 
         FIG. 8  is an exploded perspective view of the items shown in  FIG. 3 . 
     
    
    
     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, 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 provide torque to one or more traction wheel assemblies that may include a tire mounted on a wheel. The wheel may be mounted to a wheel hub that may be rotatable about a wheel axis. 
     One or more axle assemblies may be provided with the vehicle. As is best shown with reference to  FIGS. 1 and 2 , the axle assembly  10  may include a housing assembly  20 , a differential assembly  22 , and at least one axle shaft  24 . As is best shown in  FIG. 2 , the axle assembly  10  may also include a drive pinion  26  and a preload nut  28 . 
     Referring to  FIGS. 1 and 2 , the housing assembly  20  may receive various components of the axle assembly  10 . In addition, the housing assembly  20  may facilitate mounting of the axle assembly  10  to the vehicle. For instance, the housing assembly  20  may include an axle housing  30 , a differential carrier  32 , and optionally an electric motor housing  34  if an electric motor is provided with the axle assembly  10 . 
     Referring to  FIG. 2 , the axle housing  30  may at least partially receive the differential assembly  22 . Optionally, the axle housing  30  may receive and support the axle shafts  24 . 
     The differential carrier  32  may be mounted to the axle housing  30 . The differential carrier  32  may support the differential assembly  22 . 
     The differential assembly  22  may be at least partially received in the housing assembly  20 . The differential assembly  22  may be rotatable about a differential axis  40  and may transmit torque to the axle shafts  24  and wheels. The differential assembly  22  may be operatively connected to the axle shafts  24  and may permit the axle shafts  24  to rotate at different rotational speeds in a manner known by those skilled in the art. The differential assembly  22  may have a ring gear  42  that may have teeth the mate or mesh with the teeth of a gear of a drive pinion  26 . Accordingly, the differential assembly  22  may receive torque from the drive pinion  26  via the ring gear  42  and transmit torque to the axle shafts  24 . 
     Referring to  FIGS. 1 and 2 , the axle shafts  24  may transmit torque from the differential assembly  22  to corresponding wheel hubs and wheels. Two axle shafts  24  may be provided such that each axle shaft  24  extends through a different arm portion of the axle housing  30 . The axle shafts  24  or a portion thereof may extend along and may be rotatable about an axis, such as the differential axis  40 . Each axle shaft  24  may have a first end and a second end. The first end may be operatively connected to the differential assembly  22 . The second end may be disposed opposite the first end and may be operatively connected to a wheel. Optionally, gear reduction may be provided between an axle shaft  24  and a wheel. 
     Referring to  FIGS. 2 and 8 , the drive pinion  26  may transmit torque between a power source or torque source and the differential assembly  22  via the ring gear  42 . The power source may be of any suitable type. For instance, the power source may be an electrical power source or a non-electrical power source. An example of an electrical power source is an electrical machine like an electric motor. An example of a non-electrical power source is an internal combustion engine. In the configuration shown in  FIG. 2 , the power source is configured as an electric motor that is provided with the axle assembly  10 ; however, it is contemplated that the power source, whether electrical or non-electrical, may not be provided with the axle assembly  10 . For instance, a power source may be located remotely from the axle assembly  10  and may be operatively connected to the axle assembly  10  via a linkage like a shaft. A power source that is configured as an electric motor may include a stator  50  and a rotor  52 . In the configuration shown, the stator  50  is received inside the housing assembly  20  while the rotor  52  is received inside the stator  50 . The rotor  52  may extend around and may be rotatable about an axis with respect to the stator  50 . The rotor  52  may be operatively connected to the drive pinion  26  in any suitable manner, such as via a transmission or gear reduction module  60 . 
     Referring to  FIGS. 2, 3 and 8 , the drive pinion  26  may be rotatable about an axis  70 , which may also be referred to as a drive pinion axis. The axis  70  may be disposed substantially perpendicular to the differential axis  40 . In a configuration in which the axle assembly  10  includes an electric motor, the axis  70  may be the same as the axis about which the rotor  52  may rotate or may differ from the axis about which the rotor  52  may rotate. 
     The drive pinion  26  may extend along or around the axis  70 . In at least one configuration, the drive pinion  26  may include a gear  80  and a shaft  82 . 
     The gear  80  may be disposed at or near an end of the shaft  82 . The gear  80  may have a plurality of teeth that may mate with corresponding teeth on the ring gear  42 . The gear  80  may be integrally formed with the shaft  82  or may be provided as a separate component that may be fixedly disposed on the shaft  82 . 
     The shaft  82  may extend from the gear  80 . For instance, the shaft  82  may extend from the gear  80  in a direction that extends away from the differential assembly  22 . In at least one configuration such as is best shown with reference to  FIGS. 3 and 8 , the shaft  82  may include a first outer surface  90 , a second outer surface  92 , a third outer surface  94 , a threaded portion  96 , a recess outer surface  98 , one or more recesses  100 , and a spline  102 . Some of these features are optional as discussed below. 
     The first outer surface  90  may extend from the gear  80  and may be an outside circumference of a portion of the shaft  82 . A first drive pinion bearing  110  may be disposed on the first outer surface  90  and may rotatably support the drive pinion  26 . The first drive pinion bearing  110  may have any suitable configuration. For instance, the first drive pinion bearing  110  may be configured as a roller bearing assembly that may include a plurality of rolling elements  112  that may be disposed between an inner race  114  and an outer race  116 . The inner race  114  may extend around and may be disposed on the first outer surface  90 . The outer race  116  may extend around the rolling elements  112  and may be disposed on supporting component, such as the differential carrier  32 . 
     The second outer surface  92 , if provided, may be positioned along the axis  70  or axially positioned between the first outer surface  90  and the third outer surface  94 . The second outer surface  92  may be an outside circumference of a portion of the shaft  82  and may have a smaller diameter than the first outer surface  90 . One or more spacers  120  may be disposed on the second outer surface  92 . The spacers  120  may be configured as rings that may encircle the shaft  82  and may be axially positioned between the inner races  114 ,  114 ′ of the drive pinion bearings  110 ,  110 ′ to inhibit axial movement of the inner races  114 ,  114 ′ toward each other. 
     The third outer surface  94 , if provided, may be axially positioned between the second outer surface  92  and the threaded portion  96 . The third outer surface  94  may be an outside circumference of a portion of the shaft  82  and may have a smaller diameter than the second outer surface  92 . A second drive pinion bearing  110 ′ may be disposed on the third outer surface  94  and may rotatably support the drive pinion  26 . The second drive pinion bearing  110 ′ may have any suitable configuration. For instance, the second drive pinion bearing  110 ′ may be configured as a roller bearing assembly that may include a plurality of rolling elements  112 ′ that may be disposed between an inner race  114 ′ and an outer race  116 ′. The inner race  114 ′ may extend around and may be disposed on the third outer surface  94 . The outer race  116 ′ may extend around the rolling elements  112 ′, may be disposed on a supporting component, such as the differential carrier  32 . In at least one configuration, the inner race  114 ′ of the second drive pinion bearing  110 ′ may have a smaller inside diameter than the inner race  114  of the first drive pinion bearing  110 , the outer race  116 ′ of the second drive pinion bearing  110 ′ may have a smaller outside diameter than the outer race  116  of the first drive pinion bearing  110 , or both. 
     It is noted that the second outer surface  92 , the third outer surface  94 , or both may be omitted. For instance, the axial length of the first outer surface  90  may be increased and the second drive pinion bearing  110 ′, the spacers  120 , or both may be disposed on the first outer surface  90 . 
     Referring to  FIGS. 3, 4 and 8 , the threaded portion  96  may be axially positioned between the third outer surface  94  and the spline  102 . The threaded portion  96  may facilitate installation of the preload nut  28 . For instance, the threaded portion  96  may include a thread that may mate or mesh with a corresponding thread on the preload nut  28 . In at least one configuration, the threaded portion  96  may have an outside diameter that may be smaller than the diameter of the first outer surface  90 , the second outer surface  92 , the third outer surface  94 , or combinations thereof. 
     The recess outer surface  98  may be axially positioned between the gear  80  and a distal end of the shaft  82  that may be disposed opposite the gear  80 . For instance, the recess outer surface  98  may be axially positioned between the threaded portion  96  and the spline  102  and may extend between the threaded portion  96  and the spline  102 . The recess outer surface  98  may be an outside circumference of a portion of the shaft  82  and may have a smaller diameter than the first outer surface  90 , the second outer surface  92 , third outer surface  94 , the threaded portion  96 , or combinations thereof. 
     One or more recesses  100  may be provided with the recess outer surface  98 . In the configuration shown, two recesses  100  are illustrated; however, it is contemplated that a greater or lesser number of recesses  100  may be provided. A recess  100  may be disposed proximate the threaded portion  96  and may be axially positioned further from the gear  80  than the threaded portion  96  is positioned from the gear  80 . For instance, a recess  100  may be axially positioned between the threaded portion  96  and the spline  102 . In at least one configuration, the recess  100  may extend past an end of the preload nut  28  as is best shown in  FIG. 4 , in which case the recess  100  may be disposed closer to the spline  102  than the preload nut  28  is disposed to the spline  102 . 
     A recess  100  may extend from the recess outer surface  98  toward the axis  70  and may have any suitable configuration. For instance, a recess  100  may be configured as a blind hole or a through hole. In addition, a recess  100  may have any suitable shape. In the configuration shown, each recess  100  is depicted as being an elongated slot that has a generally oval-shaped configuration in which the length of the recess  100  in an axial direction is greater than its width in a circumferential direction. For example, the axial length of the recess  100  may be at least twice its width. It is also contemplated that a recess  100  may be provided with other shapes and may also have an axial length that is less than its width. For instance, a recess  100  may be configured as a groove that may extend continuously around the axis  70 . In at least one configuration, the recess  100  may be at least partially defined by a recess bottom surface  130 , a first lateral side  132 , and a second lateral side  134 , which are best shown with reference to  FIGS. 4 and 5 . 
     The recess bottom surface  130  may be disposed at a bottom of the recess  100 . As such, the recess bottom surface  130  may be disposed closer to the axis  70  than the recess outer surface  98 . 
     The first lateral side  132  may extend between the recess outer surface  98  and the recess bottom surface  130 . For instance, the first lateral side  132  may extend from the recess outer surface  98  to a first end or first edge of the recess bottom surface  130 . 
     The second lateral side  134  may be disposed opposite the first lateral side  132 . The second lateral side  134  may extend between the recess outer surface  98  and the recess bottom surface  130 . For instance, the second lateral side  134  may extend from the recess outer surface  98  to a second end or second edge of the recess bottom surface  130 . 
     Referring to  FIGS. 3 and 8 , the spline  102 , if provided, may be disposed between the threaded portion  96  and the distal end of the shaft  82 . The spline  102  may include a plurality of teeth. In at least one configuration, the teeth of the spline  102  may be disposed substantially parallel to the axis  70  and may mate with a corresponding spline of another component, such as a coupling or shift collar that may operatively connect the drive pinion  26  to the power source. The spline  102  may have an outside diameter that may be larger than the diameter of the recess outer surface  98 . It is also contemplated that the spline  102  may be omitted and that the drive pinion  26  may be coupled to another component in a different manner, such as with a fastener, and that the recess outer surface  98  may be disposed proximate or may extend from an end of the shaft  82 . 
     Referring to  FIGS. 4 and 8 , the preload nut  28  may be mountable to the drive pinion  26 . In at least one configuration, the preload nut  28  may include a first end  140 , a second end  142 , a hole  144 , a thread  146 , and a deformable ring  148 . The preload nut  28  may optionally include a flange  150 , a tool engagement portion  152 , a transition region  154 , or combinations thereof. 
     The first end  140  may face away from the gear  80  and the first and second drive pinion bearings  110 ,  110 ′ when the preload nut  28  is installed on the drive pinion  26 . 
     The second end  142  may be disposed opposite the first end  140 . The second end  142  may face toward the gear  80  and the first and second drive pinion bearings  110 ,  110 ′ when the preload nut  28  is installed on the drive pinion  26 . For instance, the second end  142  may face toward and may engage or contact a washer  160  that may be axially positioned between the second drive pinion bearing  110 ′ and the preload nut  28 . 
     The hole  144  may be a through hole that may extend from the first end  140  to the second end  142 . The shaft  82  of the drive pinion  26  may be received in and may extend through the hole  144 . 
     The thread  146  may be disposed in the hole  144 . The thread  146  may mate with the threaded portion  96  of the drive pinion  26  to help secure the preload nut  28  to the drive pinion  26 . In at least one configuration, the thread  146  may generally extend from the first end  140  toward the second end  142 . The thread  146  may not be provided with the deformable ring  148 . 
     The deformable ring  148  may extend from the first end  140  toward the second end  142 . For instance, the deformable ring  148  may extend from the first end  140  to the thread  146 . As such, the deformable ring  148  may be disposed proximate the thread  146 , the threaded portion  96 , or both. In at least one configuration, the deformable ring  148  may extend continuously around the axis  70 ; however, it is contemplated that the deformable ring  148  may be discontinuous. The deformable ring  148  may be deformable to engage the shaft  82  inside a recess  100  to inhibit rotation of the preload nut  28  about the axis  70  with respect to the drive pinion  26  as will be discussed in more detail below. The deformable ring  148  may be at least partially defined by an interior side  170  and an exterior side  172 . 
     The interior side  170  may face toward the shaft  82  of the drive pinion  26 . For example, the interior side  170  may face toward the recess outer surface  98 . At least a portion of the interior side  170  may face toward and may overlap a recess  100 . The interior side  170  may be spaced apart from the recess outer surface  98  prior to deformation or engagement with the drive pinion  26  as will be discussed in more detail below. 
     The exterior side  172  may be disposed opposite the interior side  170 . In at least one configuration, the wall thickness of the deformable ring  148  in a radial direction from the interior side  170  to the exterior side  172  may be less than the wall thickness of the flange  150 , the tool engagement portion  152 , the transition region  154 , or combinations thereof. 
     The flange  150  may be disposed at the second end  142  and may extend from the second end  142  of the preload nut  28 . As such, the flange  150  may engage or contact the washer  160  or the inner race  114 ′ of the second drive pinion bearing  110 ′ if the washer  160  is omitted. The flange  150  may extend further from the axis  70  or may have a larger diameter than the tool engagement portion  152 . 
     The tool engagement portion  152  may be axially positioned between the flange  150  and the deformable ring  148 . For instance, the tool engagement portion  152  may extend from the flange  150  to the transition region  154 . In at least one configuration, the tool engagement portion  152  may include a plurality of intersecting flat surfaces that may be grasped by a tool, such as a wrench or socket, to facilitate tightening and loosening of the preload nut  28 . In at least one configuration, the tool engagement portion  152  may extend further from the axis  70  than the deformable ring  148  and the transition region  154 . 
     The transition region  154  may extend axially between the tool engagement portion  152  and the deformable ring  148 . In at least one configuration, the transition region  154  may be tapered such that the diameter of the transition region  154  becomes progressively smaller in an axial direction that extends from the tool engagement portion  152  to the deformable ring  148 . As such, the transition region  154  may extend further from the axis  70  than the deformable ring  148 . 
     Referring to  FIGS. 2-7 , a method of assembly will now be discussed. 
     First, the drive pinion  26 , first and second drive pinion bearings  110 ,  110 ′, and spacers  120  may be assembled, which may result in positioning of these components as is shown in  FIGS. 2 and 3 . Assembly of these components may occur in any appropriate sequence. For instance, the first drive pinion bearing  110 , the second drive pinion bearing  110 ′, or both may be installed on a supporting component, such as the differential carrier  32 , prior to inserting the drive pinion  26  into a drive pinion bearing. Alternatively, the first drive pinion bearing  110 , second drive pinion bearing  110 ′, spacers  120 , or combinations thereof may be installed on the shaft  82  of the drive pinion  26  before installation on the supporting component. As a nonlimiting example, the first drive pinion bearing  110  may be mounted to the differential carrier  32 , the shaft  82  of the drive pinion  26  may be inserted through the hole in the inner race  114  of the first drive pinion bearing  110 , the spacers  120  may be slid onto the shaft  82 , and then the second drive pinion bearing  110 ′ may be slid onto the shaft  82  and into engagement with the differential carrier  32  such that the spacers  120  may be axially positioned between the inner race  114  of the first drive pinion bearing  110  and the inner race  114 ′ of the second drive pinion bearing  110 ′. 
     Next, the washer  160  may be slid onto the shaft  82  and into engagement with the second drive pinion bearing  110 ′. 
     Next, the preload nut  28  may be installed on the shaft  82 . The preload nut  28  may be installed by engaging or mating the thread  146  of the preload nut  28  with the threaded portion  96  of the drive pinion  26  and rotating the preload nut  28  in a first rotational direction about the axis  70 . The preload nut  28  may be rotated to advance the preload nut  28  in an axial direction toward the gear  80  and may be rotated and tightened until the preload nut  28  exerts a desired preload force against the first drive pinion bearing  110 , the second drive pinion bearing  110 ′, or both. At this point, the positioning of the preload nut  28  may resemble that shown in  FIGS. 2-5 , with the deformable ring  148  of the preload nut  28  extending around at least a portion of the recess  100 , disposed outside of the recess  100 , and spaced apart from the drive pinion  26 . 
     Next, the deformable ring  148  may be deformed into the recess  100  and into engagement with the drive pinion  26  to inhibit the preload nut  28  from rotating with respect to the drive pinion  26 . This is best shown with reference to  FIGS. 6 and 7 . For instance, a tool having one or more engagement features  180 , which are shown in  FIG. 7 , may engage the exterior side  172  of the deformable ring  148 . An engagement feature  180  may be actuated to exert a compressive force against the exterior side  172  of the deformable ring  148  that may be sufficient to compress and form at least a portion of the deformable ring  148  into the recess  100 . An engagement feature  180  may have any suitable configuration. For example, an engagement feature  180  may be configured as a punch or crimp head and may optionally have a tip that may be sized slightly smaller than the recess  100 . In the configuration shown in  FIG. 7 , two engagement features  180  are illustrated that are disposed directly opposite each other and are aligned with corresponding recesses  100  in the drive pinion  26 . The engagement features  180  may be actuated at the same time to compress the deformable ring  148  into each recess  100 . 
     Referring to  FIG. 6 , a portion of the first end  140  of the preload nut  28  may be received in the recess  100  after the deformable ring  148  is deformed. Alternatively, the first end  140  of the preload nut  28  may not be received in the recess  100  if the deformable ring  148  has a sufficient axial length to extend past the end of the recess  100  that is disposed closest to the spline  102 . In such a configuration, a portion of the deformable ring  148  that is disposed between the first end  140  and the thread  146  may be deformed into the recess  100  by an engagement feature  180 . 
     Referring to  FIGS. 6 and 7 , the deformable ring  148  may engage or contact various surfaces that may define the recess  100  after deformation. For instance, the deformable ring  148  may engage or contact the recess bottom surface  130 , the first lateral side  132 , the second lateral side  134 , or combinations thereof. The deformable ring  148  need not engage the recess bottom surface  130 , both lateral sides, or the axial ends or left and right ends of the recess  100  from the perspective shown in  FIG. 6 . However, engaging the deformable ring  148  with the first lateral side  132  and the second lateral side  134  may inhibit rotation of the preload nut  28  in first and second rotational directions about the axis  70  with respect to the drive pinion  26  and thereby inhibit tightening or loosening of the preload nut  28 . 
     Referring to  FIG. 7 , in a configuration having multiple recesses  100 , the interior side  170  of the deformable ring  148  may be at least partially spaced apart from the recess outer surface  98  of the shaft  82  after the deformable ring  148  has been compressed or deformed. For instance, the interior side  170  may be at least partially spaced apart from the recess outer surface  98  between adjacent recesses  100 , such as to the left and right of the recesses  100  from the perspective shown. It is also contemplated that the interior side  170  may engage the recess outer surface  98  continuously around the axis  70  once the deformable ring  148  has been compressed or deformed. 
     The engagement feature  180  may be disengaged from or retracted away from the deformable ring  148  after the deformable ring  148  has been deformed into the recess  100 . 
     An axle assembly having a drive pinion and preload nut as described above may allow a preload nut to be installed and secured to prevent or inhibit rotation of the preload nut with respect to the drive pinion, which may allow a bearing preload force to be set and maintained. Maintaining a desired preload force may prevent skidding of a bearing assembly, reduce friction and heating of the bearing, and help improve bearing life, thereby reducing maintenance costs. Moreover, the preload nut may be installed without the use of additional locking devices or components, such as mechanical locking devices like nylon nuts, split washers, or adhesives like a thread locking fluid, which may help reduce costs and assembly time. Moreover, the deformable portion of the preload nut may be mechanically separable or disengageable from the drive pinion in the event that removal of the preload nut from the drive pinion is subsequently desired. For instance, the deformable portion of the preload nut that is received in a recess may be pushed out of the recess or severed from the preload nut to permit the preload nut to be easily unthreaded from the drive pinion without damaging the threads of the drive pinion, which may allow the drive pinion to be removed from the axle assembly and subsequently reused, thereby reducing costs. 
     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.