Abstract:
A universal joint includes a spider, first and second yokes drivingly interconnected by the spider, a plurality of bearing cups and a plurality of retaining members. The first yoke includes spaced apart arms with apertures extending through each arm. The apertures are coaxially aligned with one another and include a circumferential groove spaced apart from an edge of the arm. Each bearing cup is positioned within one of the apertures and in receipt of one of the trunnions. A portion of each bearing cup is positioned in communication with a corresponding groove. Each retaining member is operable to complement the size and shape of the corresponding groove, bearing cup and aperture such that each retaining member couples one of the bearing cups to its associated arm.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This is a continuation application of co-pending U.S. patent application Ser. No. 11/062,934 filed Feb. 22, 2005. The entire disclosure of the above application is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     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.  
         [0003]     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.  
         [0004]     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. 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 variations within 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 exists, relative motion may occur between the bearing cup and yoke bores, resulting in noise or vibration during use. 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. Unfortunately, the universal joint assembled by these technologies may not be as rotationally balanced as desired.  
       SUMMARY OF THE INVENTION  
       [0005]     Accordingly, the present invention is directed to overcoming the disadvantages commonly associated with the manufacture and balancing of conventional universal joints. Therefore, it is an object of the present invention to reduce the number of components and cost required to construct a balanced universal joint assembly.  
         [0006]     The present invention is directed to a universal joint including a spider, first and second yokes drivingly interconnected by the spider, a plurality of bearing cups and a plurality of retaining members. The first yoke includes spaced apart arms with apertures extending through each arm. The apertures are coaxially aligned with one another and include a circumferential groove spaced apart from an edge of the arm. Each bearing cup is positioned within one of the apertures and in receipt of one of the trunnions. A portion of each bearing cup is positioned in communication with a corresponding groove. Each retaining member is operable to complement the size and shape of the corresponding groove, bearing cup and aperture such that each retaining member couples one of the bearing cups to its associated arm.  
         [0007]     The method of assembling the universal joint includes providing a yoke with a pair of arms where each of the arms has a trunnion aperture. A trunnion is installed into each trunnion aperture. A plurality of bearing cups are installed such that each bearing cup is received into one of the trunnion apertures and received onto an associated trunnion. Molten polymeric resin is injected into a groove formed in each of the arms. The groove is positioned adjacent to an associate bearing cup. The molten resin is allowed to cool to form a retaining member coupling each bearing cup to its associated arm.  
         [0008]     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  
       [0009]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a perspective view of a universal joint according to the principals of the present invention;  
         [0011]      FIG. 2  is an exploded perspective view of the universal joint shown in  FIG. 1 ;  
         [0012]      FIG. 3  is a sectional view of the retention member shown in  FIG. 1 ; and  
         [0013]      FIG. 4  is a partial sectional view of one of the yokes associated with the universal joint shown in  FIGS. 1-3 . 
     
    
     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 spider or 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  FIG. 3 . 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.  FIG. 3  depicts retention member  60  as including a polymeric ring  62  injection molded into engagement with an end face  64  of bearing cup  48 . Molten polymeric material substantially fills ring groove  30 . Ring groove  30  has a width sized to axially overlap at least a portion of an outer cylindrical wall  66  of sleeve segment  49 . In this manner, at least a portion of polymeric ring  62  circumferentially surrounds bearing cup  48 . Furthermore, end face  64  of bearing cup  48  lies in a plane intersecting groove  30 . Also, a portion of retention member  60  extends axially beyond end face  64  in a direction away from the spider. After the molten resin is injected to fill the annular groove  30  as previously described, the resin is cooled. During cooling, the polymeric material shrinks slightly causing an inner surface  68  of polymeric ring  62  to engage and grip a portion of outer cylindrical wall  66 . Therefore, polymeric ring  62  functions as an anti-rotational device to resist relative rotation between bearing cup  48  and leg  22 .  
         [0021]     As shown in  FIGS. 3 and 4 , polymeric ring  62  further includes a lug  70  integrally formed with polymeric ring  62 . Lug  70  is formed when molten resin fills an undercut or recess  72  machined in communication with groove  30 . Undercut  72  axially extends from an edge of groove  30 . Undercut  72  may radially extend a distance less than or equal to the radius of groove  30 . Undercut  72  circumferentially extends an arc length less than the entire circumference of groove  30 . Lug  70  and undercut  72  cooperate to further provide an anti-rotational device restricting polymeric ring  62  from rotation relative to leg  22 . Polymeric ring  62  includes an outer cylindrical surface  74  and an aperture  76  extending therethrough. Aperture  76  exposes end segment  51  to the atmosphere.  
         [0022]     Polymeric ring  62  may be constructed from a variety of materials including nylon, glass-filled nylon, or other injection moldable thermoplastics. These materials have sufficient strength to resist axial movement of bearing cup  48  relative to leg  22  during operation of the universal joint. However, the polymeric ring material has a shear strength which allows bearing cup  48  to be removed from aperture  28  and disconnected from leg  22  to allow the universal joint to be serviced. It is contemplated that the retention member is operable to be sheared into at least two pieces by application of force to the spider to allow the bearing cups to translate within the apertures and disassemble the universal joint. Because the joint was originally equipped with ring groove  30 , the joint may be serviced and reassembled using a standard planar snap ring (not shown).  
         [0023]     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 formed by an injection molding process to automate assembly and increase the likelihood of producing a properly aligned and balanced universal joint. Additionally the cost and time required for manufacturing the universal joint are reduced.  
         [0024]     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.