Abstract:
A universal joint includes a yoke with a leg having an aperture extending therethrough. The aperture includes an annular groove. The universal joint also includes a cruciform having a trunnion, a bearing cup positioned in the aperture and mounted on the trunnion and a retention member including a stepped cross-section. The retention member is disposed within the groove to fill the gap remaining between the groove edge and the bearing cup.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention generally relates to a universal joint for use in a driveline of a motor vehicle. More specifically, the present invention pertains to a universal joint equipped with a retention member for securing a bearing cup in a yoke.  
           [0002]    As is commonly known, universal joints are used in motor vehicle driveline applications for interconnecting a pair of rotary shafts and permitting changes in angularity therebetween. Many conventional universal joints include a pair of bifurcated yokes which are secured to the rotary shafts. The bifurcated yokes are interconnected by a spider or a cruciform for rotation about independent axes. The spider includes four orthogonal trunnions with each opposing pair of axially aligned trunnions 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 one of the pairs of trunnions.  
           [0003]    Various retention methods have been developed for securing the bearing cups to the yokes in a manner wherein the rotary axis of each yoke is aligned centrally with respect to the rotary axis of the spider. Traditional bearing cup retention methods include the use of grooves and planar snap rings. However, this method has one or more disadvantages such as, for example, excessive machining requirements, limited serviceability, and high cost of manufacture. In particular, one type of conventional universal joint utilizes a planar snap ring seated in a circumferential groove machined into the bore formed in the yokes for axially retaining the bearing cups. However, due to the dimensional variation of each component, either an interference condition or an excess clearance between the bearing cup and the snap ring is accumulated. If an interference condition exists, one or both of the bifurcated yokes is mechanically deformed to increase the spacing between the previously machined grooves. If an excess clearance condition exits, a Belleville washer may be disposed between the bearing cup and the snap ring to preload the bearing. Alternatively, an assembler may be provided with a plurality of snap rings having different thicknesses. The assembler uses a trial and error method to fit the largest snap ring possible within the clearance.  
           [0004]    Other universal joint retention devices attempt to compensate for the dimensional variation in the components but sacrifice serviceability. Several examples of bearing cup retention arrangements and methods associated with conventional universal joints are disclosed in U.S. Pat. Nos. 3,062,026, 3,178,907 and 4,000,628.  
         SUMMARY OF THE INVENTION  
         [0005]    Accordingly, the present invention is directed to overcoming the disadvantages commonly associated with the manufacture and subsequent service of conventional universal joints. Therefore, it is an object of the present invention to reduce the number of components and cost required to construct an easily serviceable universal joint assembly.  
           [0006]    The present invention is directed to a universal joint for interconnecting a pair of rotating shafts. The universal joint includes a yoke with a leg having an aperture extending therethrough. The aperture includes an annular groove. The universal joint also includes a cruciform having a trunnion, a bearing cup positioned in the aperture and mounted on the trunnion and a retention member including a stepped cross-section. The retention member is disposed within the groove to fill the gap remaining between the groove edge and the bearing cup. The stepped cross-section of the retention member at least partially enters the groove and engages the bearing cup.  
           [0007]    Further areas of applicability of the present invention will become apparent from the detailed description provided herein after. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0009]    [0009]FIG. 1 is a perspective view of a universal joint according to the principals of the present invention;  
         [0010]    [0010]FIG. 2 is an exploded perspective view of the universal joint shown in FIG. 1;  
         [0011]    [0011]FIG. 3 is a perspective view of the retention member according to the principals of the present invention;  
         [0012]    [0012]FIG. 4 is a sectional view of the retention member shown in FIG. 3; and  
         [0013]    [0013]FIG. 5 is a partial sectional view of one of the yokes associated with the universal joint shown in FIGS. 1 and 2.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    In general, the present invention is directed to a universal joint of the type used in motor vehicle driveline applications for interconnecting rotating shafts in a manner permitting changes in angularity therebetween.  
         [0015]    Referring to FIGS. 1 and 2, a universal joint  10  is shown connecting a first shaft  12  to a second shaft  14 . In general, universal joint  10  includes a first yoke  16  attached to an end of first shaft  12 , a second yoke  18  attached to an end of second shaft  14  and a cruciform  20  interconnecting first yoke  16  to second yoke  18 . The first yoke  16  is bifurcated and includes a pair of laterally spaced-apart legs  22  which are preferably symmetrical with respect to the rotary axis of first shaft  12 , as denoted by construction line A. Legs  22  include an inboard surface  24  and an outboard surface  26  with an aperture  28  extending therebetween. Apertures  28  are aligned on a first trunnion axis, as denoted by construction line Y, which passes through and is orthogonal with respect to rotary axis A of first shaft  12 . Each aperture  28  is a throughbore and includes an annular ring groove  30  positioned between the inboard surface  24  and the outboard surface  26 .  
         [0016]    Second yoke  18  is bifurcated and includes a pair of laterally-spaced legs  32  which are preferably symmetrical with respect to the rotary axis of second shaft  14 , as denoted by construction line B. Legs  32  include an inboard surface  34  and an outboard surface  36  with an aperture  38  extending therebetween. Apertures  38  are aligned on a second trunnion axis, as denoted by construction line Z, which passes through and is orthogonal with respect to rotary axis B of second shaft  14 . Apertures  38  are throughbores which include an annular groove  40  formed between the inboard surface  34  and the outboard surface  36 . It should be noted that the shape and dimensions of apertures  28  and  38  may either be identical or different depending on the particular dimensions of cruciform  20  used therewith. It should also be noted that the annular ring grooves  30  and  40  may be formed by machining, casting or by similar technique.  
         [0017]    As best seen in FIG. 2, cruciform  20  includes a central hub  42  from which a pair of first trunnions  44  and a pair of second trunnions  46  extend. First trunnions  44  are orthogonal with respect to second trunnions  46 . First trunnions  44  are adapted for insertion into apertures  28  in legs  22  of first yoke  16  so as to be axially aligned on first trunnion axis Y. Similarly, second trunnions  46  are adapted to be inserted into apertures  38  in legs  32  of second yoke  18  so as to be axially aligned on second trunnion axis Z. With first trunnions  44  and second trunnions  46  installed in first and second yokes  16  and  18 , respectfully, trunnion axes Y and Z pass through a common plane which orthogonally intersects the rotary axis of cruciform  20 , shown in FIG. 1 by construction plane C.  
         [0018]    Universal joint  10  also includes a first pair of bearing cups  48  adapted to be mounted in apertures  28  and a second pair of bearing cups  50  adapted to be mounted in apertures  38 . First bearing cups  48  are provided for receiving and rotatably supporting first trunnions  44  in apertures  28 . Similarly, second bearing cups  50  are provided for receiving and rotatably supporting second trunnions  46  in apertures  38 . As seen, bearing cups  48  and  50  each include a tubular sleeve segment  49  enclosed by an end segment  51 . A roller bearing assembly  52  is mounted in the sleeve segment for rotatably supporting trunnions  44  and  46  therein. In addition, annular elastomeric seals  54  are mounted on trunnions  44  and  46 , respectively, for providing a sealed relationship with respect to the open end of the sleeve segments  49  of bearing cups  48  and  50 , respectively.  
         [0019]    To assemble the universal joint  10 , one of the bearing cups  48  is mounted on one of the first trunnions  44  prior to insertion thereof into its corresponding aperture  28  such that the terminal end surface of the trunnion is placed in abutting engagement with the end segment  51  of its corresponding bearing cup. Alternatively, trunnions  44  and  46  may be installed into corresponding apertures  28  and  38  with bearing cups  48  and  50  thereafter installed into apertures  28  and  38 . For purposes of describing the cruciform alignment and retention device used in association with yokes  16  and  18 , reference is now directed to FIGS. 3, 4 and  5 . However, while the following disclosure is specifically directed to retention of cruciform  20  relative to first yoke  16 , it is to be understood that a similar process is contemplated for use with second yoke  18 .  
         [0020]    Once rotary axis A of first shaft  12  is co-axially aligned with rotary axis B of second shaft  14 , a retention member  60  cooperates with each bearing cup  48  to retain the afore-mentioned components in relation to each other. In reference to FIGS. 3 and 4, retention member  60  includes a C-shaped ring  62  having a bottom surface  64 , a series of stepped surfaces  66 ,  68  and  70 , and a top surface  72 . Surfaces  64 ,  66 ,  68 ,  70  and  72  are positioned substantially parallel to one another. A first thickness X 1  is defined by the distance between surfaces  64  and  66 . A second thickness X 2  is defined by the distance between surfaces  64  and  68 . A third thickness X 3  is defined as the distance between surfaces  64  and  70 . A fourth or overall thickness X 4  is defined by the distance between surfaces  64  and  72 . Retention member  60  is shown having an exemplary number of stepped surfaces  66 - 70 , however, it should be appreciated the retention member may include any number of surfaces selectively insertable within a gap defined by bearing cup  48  and ring groove  30  without departing from the scope of the present invention. As best shown in FIG. 4, thicknesses X 1 -X 4  increase in a direction from an outer edge  74  toward an inner edge  76  of retention member  60 . Ring  62  terminates at first and second ends  78  and  80 , respectively, and includes apertures  82  extending therethrough to facilitate installation of retention member  60  as described in greater detail hereinafter. In order to provide resistance to permanent deformation during operation, the retention member  60  is preferably constructed from a resilient material such as spring steel.  
         [0021]    Referring to FIG. 5, universal joint  10  of the present invention is presented in an assembled state. Preferably, retention member  60  is installed by reducing the outer diameter of ring  62  with a tool (not shown) acting in cooperation with apertures  82  and disposing retention member  60  within aperture  28 . Retention member  60  is inserted within the aperture  28  until bottom surface  64  contacts end segment  51  of bearing cup  48 . After retention member  60  is positioned adjacent ring groove  30 , the tool is released and ring  62  expands into ring groove  30 . One skilled in the art will appreciate that the number of stepped surfaces positioned within groove  30  is merely exemplary and corresponds to the “stack-up” or summation of component tolerances described earlier. Care is taken to assure that the overall thickness of retention member  60  is great enough to account for component variation. Furthermore, the joint is designed and toleranced to ensure that at least one stepped surface may enter ring groove  30  to retain bearing cup  48 .  
         [0022]    Therefore, it should be appreciated that the configuration and operation of universal joint  10  provides both manufacturing and functional advantages over the prior art. Specifically, the universal joint  10  of the present invention utilizes a retention member to minimize component count, thereby easing assembly and reducing the cost of manufacture.  
         [0023]    While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.