Patent Abstract:
A drive pinion fastening assembly is provided. The drive pinion fastening assembly includes a drive pinion, a pinion sleeve, an external spline, and a pinion fastener. The pinion sleeve is disposed on and engaged with the drive pinion. The external spline is formed on one of the drive pinion and the pinion sleeve for engaging a power transmission component. The pinion fastener is disposed on and engaged with the drive pinion. The pinion fastener militates against axial movement of the pinion sleeve with respect to the drive pinion. The drive pinion fastening assembly is compact, able to handle increased torque loads, and is easy to manufacture.

Full Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims the benefit of priority to U.S. Provisional Application No. 61/713,911 filed on Oct. 15, 2012, which is incorporated herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to drivelines for vehicles and more particularly to a fastening assembly for a drive pinion. 
       BACKGROUND OF THE INVENTION 
       [0003]    Conventionally, drive pinions used with axle assemblies have been drivingly engaged with other components of a drivetrain of a vehicle using a companion flange. The companion flange is a hollow annular body which has a substantially “L” shaped cross-section. The companion flange typically provides a location for securing a portion of a universal joint thereto; however, other components of a drivetrain may be coupled thereto. An outermost portion of the companion flange usually includes a plurality of apertures formed therein, which receive threaded fasteners to secure a component to the companion flange. 
         [0004]    The companion flange, however, has limitations that restrict its use in certain applications. A design of the companion flange can become excessive in size as a torque requirement of a drivetrain increases. Ease of manufacturability of the companion flange can be decreased in certain applications. Further, assembly of the drivetrain including the companion flange may be time consuming. Consequently, selecting the companion flange as a drivetrain component may become costly and problematic. 
         [0005]    It would be advantageous to develop a fastening assembly for a drive pinion that is compact, able to handle increased torque loads, and is easy to manufacture. 
       SUMMARY OF THE INVENTION 
       [0006]    Presently provided by the invention, a fastening assembly for a drive pinion that is compact, able to handle increased torque loads, and is easy to manufacture, has surprisingly been discovered. 
         [0007]    In one embodiment, the present invention is directed to a drive pinion fastening assembly. The drive pinion fastening assembly comprises a drive pinion, a pinion sleeve, an external sleeve, and a pinion fastener. The pinion sleeve is disposed on and engaged with the drive pinion. The external spline is formed on one of the drive pinion and the pinion sleeve for engaging a power transmission component. The pinion fastener is disposed on and engaged with the drive pinion. The pinion fastener militates against axial movement of the pinion sleeve with respect to the drive pinion. 
         [0008]    In another embodiment, the present invention is directed to a drive pinion fastening assembly. The drive pinion fastening assembly comprises a drive pinion, a pinion sleeve, an external spline, and a pinion fastener. The drive pinion includes a locking spline portion. The pinion sleeve is disposed on and engaged with the drive pinion. The external spline is formed on the drive pinion for engaging a power transmission component. The pinion fastener is disposed on and engaged with the locking spline portion of the drive pinion through an interference fit. The pinion fastener militates against axial movement of the pinion sleeve with respect to the drive pinion. 
         [0009]    In yet another embodiment, the present invention is directed to a drive pinion fastening assembly. The drive pinion fastening assembly comprises a drive pinion, a pinion sleeve, an external spline, and a pinion fastener. The drive pinion includes a splined portion. The pinion sleeve includes an inner splined portion for engaging the splined portion of the drive pinion. The pinion sleeve is disposed on and engaged with the drive pinion. The external spline is formed on the pinion sleeve and engages a power transmission component. The pinion fastener includes a thread formed on an inner surface thereof. The pinion fastener is disposed on and threadingly engaged with the drive pinion. The pinion fastener militates against axial movement of the pinion sleeve with respect to the drive pinion. 
         [0010]    Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The above, as well as other advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which: 
           [0012]      FIG. 1  is a perspective view of a pinion sleeve and a pinion fastener of a pinion fastening assembly according to an embodiment of the present invention; 
           [0013]      FIG. 2  is a cross sectional view of a pinion fastening assembly according to an embodiment including the pinion sleeve and the pinion fastener illustrated in  FIG. 1 ; 
           [0014]      FIG. 3  is a perspective view of a pinion sleeve of a pinion fastening assembly according to another embodiment of the present invention; and 
           [0015]      FIG. 4  is a cross sectional view of a pinion fastening assembly according to an embodiment including the pinion sleeve and the pinion fastener illustrated in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. 
         [0017]      FIGS. 1 and 2  illustrate a drive pinion fastening assembly  100  according to an embodiment of the present invention. The drive pinion fastening assembly  100  includes a drive pinion  102 , a pinion sleeve  104 , and a pinion fastener  106 . The pinion sleeve  104  is disposed on the drive pinion  102  and is threadingly engaged with the drive pinion  102 . The pinion fastener  106  is disposed in the pinion sleeve  104  and is in engagement with the pinion sleeve  104  and the drive pinion  102 . 
         [0018]      FIG. 2  illustrates the drive pinion  102 . The drive pinion  102  is an elongate member rotatably disposed in a housing  108 . It is understood that the drive pinion  102  and the housing  108  may be used with a front axle drive assembly (not shown) or a rear axle drive assembly (not shown). The drive pinion  102  is formed by machining and heat treating a metal such as steel. A pair of bearings  110  is disposed between the drive pinion  102  and the housing  108 , to facilitate rotation of the drive pinion  102  therein. The drive pinion  102  includes a threaded portion  112 , a locking spline portion  114 , and an engagement spline portion  116 . 
         [0019]    The threaded portion  112  of the drive pinion  102  is formed on an outer surface of the drive pinion  102  adjacent the locking spline portion  114 , intermediate a first end  118  and a second end  120  of the drive pinion  102 . When the pinion sleeve  104  is disposed on the drive pinion  102 , the pinion sleeve  104  may be threadingly engaged with the threaded portion  112 . 
         [0020]    The locking spline portion  114  of the drive pinion  102  is formed on an outer surface of the drive pinion  102  between the threaded portion  112  and the engagement spline portion  116 . The locking spline portion  114  engages the pinion fastener  106  when the pinion fastener  106  is disposed thereon. The locking spline portion  114  comprises a plurality of splines in an annular arrangement; however, it is understood that the locking spline portion  114  may comprise other features for engaging the pinion fastener  106 . A diameter of the locking spline portion  114  is less than a diameter of the threaded portion  112 . 
         [0021]    The engagement spline portion  116  of the drive pinion  102  is formed adjacent an end thereof. When the drive pinion  102  is disposed in the housing  108 , the end including the engagement spline portion  116  extends therefrom. The engagement spline portion  116  comprises a plurality of splines formed on the outer surface of the drive pinion  102  in an annular arrangement. A diameter of the engagement spline portion  116  is less than a diameter of the threaded portion  112  and the locking spline portion  114 ; however, it is understood that the diameter of the engagement spline portion  116  may be substantially equal to the diameter of the locking spline portion  114 . The engagement spline portion  116  engages a power transmission component (not shown), such as a universal joint. 
         [0022]    The pinion sleeve  104  is a hollow annular body having a first end  122  and a second end  124 . As shown in  FIGS. 1 and 2 , the second end  124  has a diameter greater than a diameter of the first end  122 ; however, it is understood that the first end  122  and the second end  124  of the pinion sleeve  104  may have other sizes and shapes. At least a portion of an inner surface  126  of the pinion sleeve  104  has a thread  128  formed thereon corresponding to the threaded portion  112  of the drive pinion  102 . A fastening recess  130  is formed in the second end  124  of the pinion sleeve  104 . 
         [0023]    When the drive pinion fastening assembly  100  is assembled, the first end  122  of the pinion sleeve  104  abuts one of the bearings  110  and applies a force thereto to secure the drive pinion  102  within the housing  108 . 
         [0024]    The second end  124  of the pinion sleeve  104  extends radially outwardly from a remaining portion of the pinion sleeve  104 . As shown in  FIG. 1 , the second end  124  is shaped to facilitate engagement with a fastening tool (not shown); however, it is understood that the second end  124  may be shaped in any manner that facilitates rotation of the pinion sleeve  104 . The fastening recess  130  is hexagonal in shape and substantially corresponds to a shape of the pinion fastener  106 ; however, it is understood that other shapes may be used. 
         [0025]    The pinion fastener  106  is a member formed from a metal. The pinion fastener  106  may be formed by stamping a sheet metal, coining a workpiece, or any other suitable process. The pinion fastener  106  is disposed in the fastening recess  130 , about the drive pinion  102 , and is in driving engagement with the drive pinion  102  when the drive pinion fastening assembly  100  is assembled. The pinion fastener  106  has an inner peripheral edge  132  and an outer peripheral edge  134 . The inner peripheral edge  132  defines a circular perforation through the pinion fastener  106  and has a diameter greater than the diameter of the engagement spline portion  116  and less than the diameter of the locking spline portion  114 . The outer peripheral edge  134  is substantially hexagonal in shape and substantially corresponds to a shape of the fastening recess  130 ; however, it is understood other shapes may be used. 
         [0026]    In use, the drive pinion fastening assembly  100  facilitates securing the drive pinion  102  within the housing  108  in a manner that isolates the pinion sleeve  104  and the pinion fastener  106  from torque applied to drive pinion  102 . Torque is applied directly to the drive pinion  102  through the engagement spline portion  116 , and thus the pinion sleeve  104  and the pinion fastener  106  are isolated from torque applied to drive pinion  102 . 
         [0027]    When the drive pinion fastening assembly  100  is assembled, the drive pinion  102  is disposed through the pair of bearings  110  and the first end  118  of the drive pinion  102  including the engagement spline portion  116  extends from a perforation  136  formed in the housing  108 . Next, the pinion sleeve  104  is disposed on the drive pinion  102  and the thread  128  is engaged with the threaded portion  112 . The pinion sleeve  104  is rotated until the first end  122  contacts one of the bearings  110  and a predetermined level of torque or rotation angle is applied thereto, which secures the drive pinion  102  and the bearings  110 . Next, the pinion fastener  106  is disposed in the fastening recess  130 , with the inner peripheral edge  132  disposed against, but not engaged with, the locking spline portion  114 . 
         [0028]    To secure the pinion fastener  106  to the locking spline portion  114 , a press (not shown) or other tool is disposed against the pinion fastener  106  and a force is applied thereto in a direction of the pinion sleeve  104 . The inner peripheral edge  132  deforms as a result of the force being applied by the press, and the pinion fastener  106  becomes engaged with both the locking spline portion  114  and the pinion sleeve  104 . The pinion fastener  106  is engaged with the locking spline portion  114  through an interference fit and the pinion fastener  106  is engaged with the pinion sleeve  104  because the outer peripheral edge  134  is disposed within the fastening recess  130 . Such an arrangement militates against rotation of the pinion sleeve  104  and therefore prevents the pinion sleeve  104  from becoming unfastened as the pinion sleeve  104  is in driving engagement with the pinion fastener  106 . 
         [0029]      FIGS. 3 and 4  illustrate a drive pinion fastening assembly  200  according to another embodiment of the present invention. The drive pinion fastening assembly  200  includes a drive pinion  202 , a pinion sleeve  204 , and a pinion fastener  206 . The pinion sleeve  204  is disposed on the drive pinion  202  and is spliningly engaged with the drive pinion  202 . The pinion fastener  206  is disposed in the pinion sleeve  204  and is threadingly engaged with the drive pinion  202 . 
         [0030]      FIG. 4  illustrates the drive pinion  202 . The drive pinion  202  is an elongate member rotatably disposed in a housing  208 . It is understood that the drive pinion  202  and the housing  208  may be used with a front axle drive assembly (not shown) or a rear axle drive assembly (not shown). The drive pinion  202  is formed by machining and heat treating a metal such as steel. A pair of bearings  210  is disposed between the drive pinion  202  and the housing  208 , to facilitate rotation of the drive pinion  202  therein. The drive pinion  202  includes a splined portion  212  and a threaded portion  214  formed thereon. 
         [0031]    The splined portion  212  of the drive pinion  202  is formed on an outer surface thereof adjacent the threaded portion  214 , intermediate a first end  216  and a second end  218  of the drive pinion  202 . When the pinion sleeve  204  is disposed on the drive pinion  202 , the pinion sleeve  204  may be spliningly engaged with the splined portion  212 . 
         [0032]    The threaded portion  214  of the drive pinion  202  is formed on an outer surface of the drive pinion  202  adjacent the splined portion  212 . When the pinion fastener  206  is disposed on the threaded portion  214 , the pinion fastener  206  may be threadingly engaged with the threaded portion  214 . When the drive pinion  202  is disposed in the housing  208 , the end including the threaded portion  214  extends therefrom. A diameter of the threaded portion  214  is less than a diameter of the splined portion  212 . 
         [0033]    The pinion sleeve  204  is a hollow annular body having a first end  220  and a second end  222 . The second end  222  has a diameter greater than the first end  220 ; however, it is understood that the first end  220  and the second end  222  may have other shapes and sizes. At least a portion of an inner surface  224  of the first end  220  has an inner splined portion  226  formed thereon corresponding to the splined portion  212  of the drive pinion  202 . When the drive pinion fastening assembly  200  is assembled, the inner splined portion  226  of the pinion sleeve  204  is in driving engagement with the splined portion  212  of the drive pinion  202 . At least a portion of an outer surface  228  of the second end  222  defines an outer splined portion  230  formed thereon. The outer splined portion  230  engages a power transmission component (not shown), such as a universal joint. A portion of the first end  220  defines a fastening flange  232  in the pinion sleeve  204 . The fastening flange  232  extends radially outwardly from the first end  220  of the pinion sleeve  204 . When the drive pinion fastening assembly  200  is assembled, the first end  220  of the pinion sleeve  204  abuts one of the bearings  210  and applies a force thereto to secure the drive pinion  202  within the housing  208 . 
         [0034]    The pinion fastener  206  is a threaded fastener formed from a metal using any conventional process. The pinion fastener  206  is a conventional, hexagonally shaped, flanged nut; however, it is understood that the pinion fastener  206  may be another type of fastener and have another shape. The pinion fastener  206  is disposed within the pinion sleeve  204 , about the first end  216  of the drive pinion  202 , and is threadingly engaged with the threaded portion  214  of the drive pinion  202  when the drive pinion fastening assembly  200  is assembled. A thread  234  formed on an inner surface  236  of the pinion fastener  206  is engaged with the threaded portion  214  of the drive pinion  202 . When the drive pinion fastening assembly  200  is assembled, the pinion fastener  206  may be secured to the drive pinion  202  using a thread adhesive (not shown). 
         [0035]    In use, the drive pinion fastening assembly  200  facilitates securing the drive pinion  202  within the housing  208  in a manner that isolates the pinion fastener  206  from torque applied to drive pinion  202 . Torque is applied to the drive pinion  202  through the pinion sleeve  204 . The outer splined portion  230  of the pinion sleeve  204  is in engagement with the power transmission component, and torque is then transferred to the drive pinion  202  through the engagement of the inner splined portion  226  and the splined portion  212 . Accordingly, the pinion fastener  206  is isolated from torque applied to drive pinion  202 . 
         [0036]    When the drive pinion fastening assembly  200  is assembled, the drive pinion  202  is disposed through the pair of bearings  210  and the end of the drive pinion  202  including the threaded portion  214  extends from a perforation  238  formed in the housing  208 . Next, the pinion sleeve  204  is disposed on the drive pinion  202  and the inner splined portion  226  is engaged with the spline portion  212 . Next, the pinion fastener  206  is disposed within the second end  218  of the pinion sleeve  204 . 
         [0037]    To secure the pinion fastener  206  to the drive pinion  202 , the thread  234  of the pinion fastener  206  is then engaged with the threaded portion  214  of the drive pinion  202 . The pinion fastener  206  is rotated until a predetermined level of torque or angle of rotation is reached, which secures the drive pinion  202  and the bearings  210  within the housing  208 , and the pinion sleeve  204  to the drive pinion  202 . Such an arrangement militates against rotation of the pinion fastener  206  as a torque applied to the drive pinion  202  passes through the pinion sleeve  204  and therefore prevents the pinion fastener  206  from becoming unfastened as the pinion sleeve  204  is in driving engagement with the drive pinion  202 . 
         [0038]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Technology Classification (CPC): 5