Patent Publication Number: US-2010113166-A1

Title: Propshaft assembly with universal joint having non-conductive sleeve between yoke and bearing cup

Description:
The present invention generally relates to a propshaft assembly with a universal joint having a non-conductive sleeve between a yoke and a bearing cup. 
     As is well known, propshaft assemblies are used in motor vehicle driveline applications for interconnecting a pair of rotary shafts in a manner that permits a change in the angularity therebetween. Most conventional automotive propshafts include universal joints having a pair of bifurcated yokes which are secured to the shafts and which are interconnected by a spider or cruciform for rotation about independent axes. The spider includes four orthogonal trunions with each opposing pair of axially aligned trunions mounted in a pair of aligned bores formed in the bifurcated yokes. Typically, a bearing cup is secured in each bore and a bearing assembly is retained in the bearing cup such that each yoke is supported for pivotal movement relative to a pair of trunions. 
     In some situations, it can be possible for the propshaft to participate with other vehicle components to form a transmission path for electrical energy between the transmission and an axle assembly. There remains a need in the art for propshaft that is resistant to the transmission of electrical energy. 
     SUMMARY 
     This section provides a general summary of some aspects of the present disclosure and is not a comprehensive listing or detailing of either the full scope of the disclosure or all of the features described therein. 
     In one form, the present teachings provide a propshaft having first and second universal joints. The first universal joint has a first joint member, which is fixedly coupled to a first end of the shaft member, and a second joint member that is pivotally coupled to the first joint member. The second universal joint has a third joint member, which is fixedly coupled to a second end of the shaft member opposite the first end, and a fourth joint member that pivotally coupled to the third joint member. At least one of the second joint member and the fourth joint member is electrically insulated from the shaft member. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure, its application and/or uses in any way. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. The drawings are illustrative of selected teachings of the present disclosure and do not illustrate all possible implementations. Similar or identical elements are given consistent identifying numerals throughout the various figures. 
         FIG. 1  is a schematic illustration of a vehicle having a propshaft assembly constructed in accordance with the teachings of the present disclosure; 
         FIG. 2  is a side elevation view in partial section of the propshaft assembly of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a portion of the propshaft assembly of  FIG. 1  illustrating a first joint assembly in detail; 
         FIG. 4  is an exploded perspective view of a portion of another propshaft assembly constructed in accordance with the teachings of the present disclosure; and 
         FIG. 5  is a sectional view taken along the line  5 - 5  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS 
     With reference to  FIG. 1  of the drawings, a vehicle having a propshaft assembly that is constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral  10 . The vehicle  10  can include a driveline  12  that is drivable via a connection to a power train  14 . The power train  14  can include an engine  16  and a transmission  18 . The driveline  12  can include a propshaft assembly  20 , a rear axle assembly  22  and a plurality of wheels  24 . The engine  16  can be mounted in an in-line or longitudinal orientation along the axis of the vehicle  10  and its output can be selectively coupled via a conventional clutch to the input of the transmission  18  to transmit rotary power (i.e., drive torque) therebetween. The input of the transmission  18  can be commonly aligned with the output of the engine  16  for rotation about a rotary axis. The transmission  18  can also include an output and a gear reduction unit. The gear reduction unit can be operable for coupling the transmission input to the transmission output at a predetermined gear speed ratio. The propshaft assembly  20  can be coupled for rotation with the output of the transmission  18 . Drive torque can be transmitted through the propshaft assembly  20  to the rear axle assembly  22  where it can be selectively apportion in a predetermined manner to the left and right rear wheels  24   a  and  24   b,  respectively. 
     With reference to  FIGS. 2 and 3 , the propshaft assembly  20  can include a shaft member  40 , a first joint assembly  42  and a second joint assembly  44 . The shaft member  40  can be formed of an appropriate structural material, such as a tubular steel or aluminum material, and can be equipped with one or more inserts and/or one or more liners  50  to attenuate one or more types of vibrations (e.g., bending mode, shell mode). The shaft member  40  can be sized to transmit a predetermined amount of torque to facilitate propulsion of an automotive vehicle, such as at least about 1000 Nm. 
     The first joint assembly  42  can include a first yoke member  60 , a second yoke member  62 , a first coupling  64 , a spider  66 , a pair of first bearing assemblies  68  and a pair of second bearing assemblies  70 . 
     The first yoke member  60  can include a first coupling portion  80  and a pair of first arms  82 . The first coupling portion  80  can be configured to be fixedly coupled to the shaft member  40 , such as through a weld  84 . The first arms  82  can be disposed about a rotational axis  86  of the first yoke member  60 . A first bearing aperture  88  can be formed through each of the first arms  82  in a direction that is generally perpendicular to the rotational axis  86  of the first yoke member  60 . 
     The second yoke member  62  can include a pair of second arms  90  that can be disposed about a rotational axis  92  of the second yoke member  62 . A second bearing aperture  98  can be formed through each of the second arms  90  in a direction that is generally perpendicular to the rotational axis  92  of the second yoke member  62 . A diameter of the second bearing apertures  98  can be greater than a diameter of the first bearing apertures  88 . 
     The first coupling  64  can be fixedly coupled to the second yoke member  62  and can be configured to be coupled to the input pinion  22   a  of the rear axle assembly  22  ( FIG. 1 ) in a conventional manner. For example, the first coupling  64  and the input pinion  22   a  can include flanges  100  that can be coupled to one another via a plurality of threaded fasteners  102 . It will be appreciated, however, that other types of coupling systems can be employed to couple the first joint assembly  42  to a first shaft and as such, the first coupling  64  can be configured in any appropriate manner in accordance with such coupling systems. 
     The spider  66  can be conventional in its construction and can include first and second pairs of trunions  110  and  112 , respectively, that can be disposed along axes that are generally perpendicular to one another and orthogonal to the rotational axes  86  and  92  of the first and second yoke members  60  and  62 . 
     Each of the first bearing assemblies  68  can include a bearing cup  120  and a bearing set  122 . The bearing cup  120  can be formed of metal and can include an annular side wall  126  and an end wall  128  that can cooperate with the annular side wall  126  to form a bearing cavity  130 . The bearing set  122  can comprise a plurality of roller bearings  134 . 
     Each of the second bearing assemblies  70  can include a bearing cup  140 , a bearing set  142  and an insulator  150 . In the particular example provided, the bearing cup  140  and the bearing set  142  are identical to the bearing cup  120  and the bearing set  122  employed in the first bearing assemblies  68 . Each of the insulators  150  can be generally cup-shaped and can include an annular wall  152  and an end wall  154  that can cooperate to form an insulator cavity  156 . In the particular example provided, the end wall  154  completely closes one side of the insulator  150 , but it will be appreciated that the end wall  154  could have an annular configuration so that a portion of the end wall  154  is open. The insulators  150  can be formed of an electrically insulating material, such as a polymeric and/or ceramic material. Examples of suitable polymeric materials include polyimide, such as VESPEL® SP-1 manufactured by E.I. DuPont de Nemours and Company. Examples of suitable ceramic materials include aluminum oxide and such ceramic materials may be directly deposited onto the exterior of the bearing cups  140  of the second bearing assemblies  70 . 
     The first pair of trunions  110  can be received into the first bearing apertures  88  in the first arms  82 , while the second pair of trunions  112  can be received into the second bearing apertures  98  of the second arms  90 . Each of the bearing sets  122  and  142  can be received over (and in rolling contact with) an associated one of the first and second pairs of trunions  110  and  112 , respectively. Each of the bearing cups  120  and  140  can be received in an associated one of the first and second bearing apertures  88  and  98 , respectively, such that the bearing sets  122  and  142 , respectively, are received into the bearing cavities  130  and are in contact with an interior cylindrical surface of the annular side walls  126 . 
     An exterior surface of the annular side wall  126  of the bearing cups  120  associated with the first bearing assemblies  68  can be abutted against the interior surfaces of the first bearing apertures  88 . 
     The bearing cups  140  associated with the second bearing assemblies  70  can be received in the insulator cavities  156  such that the exterior surface of the annular side wall  126  of the bearing cups  140  can be abutted against the interior surfaces of the annular wall  152  of the insulators  150  and the end wall  128  of the bearing cups  140  can be abutted against the end wall  154  of the insulators  150 . An exterior surface of the annular wall  152  of the insulators  150  can be abutted against the interior surfaces of the second bearing apertures  98  to thereby electrically insulate the first and second yoke members  60  and  62 . 
     A retaining system  170  can be employed to inhibit movement of the bearing cups  120  and  140  and the insulators  150  in a radially outward manner. In the particular example illustrated, the retaining system  170  includes a plurality of retaining ring grooves  172 , which can be formed into each of the first and second arms  82  and  90  about at least a portion of the first and second bearing apertures  88  and  90 , and a plurality of internal retaining (snap) rings  174  that can be received into corresponding ones of the retaining ring grooves  172 . It will be appreciated, however, that various other types of retaining systems can be employed, including an adhesive based retaining system such as that which is described in U.S. Pat. No. 7,278,212, the disclosure of which is hereby incorporated by reference as if fully set forth in detail herein. As such, those of skill in the art will appreciate that the particular retaining system  170  illustrated in the accompanying drawings does not limit the scope of the invention in any manner. 
     In the particular example provided, the insulator  150  can be sized to engage the bearing cup  140  in a line-to-line or light press-fit manner, as well as to engage the second arm  90  in a press-fit manner to thereby inhibit rotation of the insulator  150  and the bearing cup  140  relative to the second arms  90 . It will be appreciated, however, that other means may be employed (additionally or alternatively) to inhibit rotation of the insulator  150  and the bearing cup  140  relative to the second arms  90 . For example, the exterior surface of the annular wall  152  of the bearing cup  140  and the insulator cavity  156  of the insulator  150  can have mating, non-circular transverse cross-sections (i.e., they can be non-cylindrically shaped). In this regard, flats or other features can be employed to inhibit relative rotation between the bearing cup  140  and the insulator  150 . Additionally or alternatively, an adhesive, staking and/or mechanical fasteners can be employed to secure the insulators  150  to the bearing cup  140  and/or the second arms  90 . 
     The second joint assembly  44  can be identical to the first joint assembly  42  except that a second coupling  200  can be coupled to the second yoke member  62 . The second coupling  200  can be configured to be coupled to the output shaft  18   a  ( FIG. 1 ) of the transmission  18  ( FIG. 1 ) in a conventional manner. For example, one of the output shaft  18   a  ( FIG. 1 ) and the second coupling  200  can include a male splined shaft  202  that can be configured to be matingly received into a female splined aperture (not specifically shown) formed in the other one of the output shaft  18   a  ( FIG. 1 ) and the second coupling  200 . It will be appreciated, however, that other types of coupling systems can be employed to couple the second joint assembly  44  to a second shaft and as such, the second coupling  200  can be configured in any appropriate manner in accordance with such coupling systems. 
     With reference to  FIGS. 4 and 5 , a portion of an alternatively constructed propshaft assembly  20   a  is illustrated in which the second yoke member  62   a,  the bearing cup  140   a,  the insulator  150   a  and the retaining system  170   a  are different from that which is illustrated in  FIG. 2  and described above. In addition to the snap rings  174 , the retaining system  170   a  can employ an adhesive  208  for coupling the bearing cup  140   a  to the insulator  150   a.  To facilitate the use of an adhesive, the second yoke member  62   a  can include one or more adhesive apertures  210 , which can be formed through the second arms  90   a  generally orthogonal to the rotational axis  92  ( FIG. 3 ) of the second yoke member  62   a  and axis of the second bearing apertures  98   a,  an adhesive groove  212  formed in the annular side wall  126   a  of the bearing cup  140   a  and one or more apertures  214  can be formed through the annular wall  152   a  of the insulator  150   a.  Optionally, a circumferentially-extending groove  216  can be formed concentric with the second bearing apertures  98   a  and can intersect the adhesive apertures  210 . The adhesive  208  can be injected into one (or more) of the adhesive apertures  210 . The adhesive  208  can flow in the space between the second arm  98   a  and the insulator  150   a  (e.g., around the grooves  216  in the second arms  92   a  if so configured), through the apertures  214  in the insulator  150  and into the groove  212  in the bearing cup  140   a.  Once cured, the adhesive  208  can mechanically lock the bearing cup  140   a  to the insulator  150   a,  even if the adhesive  208  does not bond to either of the bearing cup  140   a  or the insulator  150   a.    
     It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various examples is expressly contemplated herein, even if not specifically shown or described, so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.