Universal joint with thrust washer

A universal joint for interconnecting a pair of rotating shafts and a method of assembling the universal joint. The universal joint includes a pair of yokes secured to the shafts and a cruciform for interconnecting the yokes. Both yokes are bifurcated to define a pair of laterally-spaced legs. Each leg has an aperture which includes a first bore adapted to receive a bearing cup therein and a second bore into which an end portion of the bearing cup extends. Each bearing cup rotatably supports one of four orthogonal trunnions extending from the cruciform. With respect to each of the yokes, a pair of axially-aligned trunnions, with bearing cups mounted thereon, are installed into the apertures so as to support the cruciform between the legs of the yoke. Thereafter, a retention member is inserted in the second bore of each aperture such that one surface of the retention member rests on the bearing cup. After the rotary axis of the first shaft is aligned with the rotary axis of the second shaft, an edge portion of the legs surrounding the second bore of each aperture is deformed to define one or more projections which engage the opposite surface of the retention member. The projections secure the retention members within the second bore of the apertures, thereby fixing the axial position of the bearing cups and trunnions relative to the yoke.

BACKGROUND OF THE INVENTION

The present invention relates generally to universal joints for use in motor vehicle driveline applications. More particularly, the present invention relates to an improved structure for a thrust washer for use in a bearing cup assembly that is adapted to be mounted on a cruciform trunnion as part of a universal joint.

As is well known, universal joints are used in motor vehicle driveline applications for interconnecting a pair of rotary shafts in a manner which accommodates changes in the angularity therebetween. Most conventional universal joints include a pair of bifurcated yokes which are secured to the shafts and which are interconnected by a cruciform for rotation about independent axes. The cruciform 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 a pair of the trunnions. In addition, it is known to use a thrust washer between the trunnion and the bearing cup to absorb the radially-directed thrust forces which may occur therebetween.

SUMMARY OF THE INVENTION

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific example, while indicating a preferred embodiment of the invention, is 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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

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. The present invention is further directed to a cruciform assembly for interconnecting the yokes of such a universal joint. Still further, the present invention is directed to a thrust washer used in a bearing cup assembly which is installed on the cruciform assembly.

Referring to the drawings, 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 first shaft 12 , a second yoke 18 attached to second shaft 14 , and a cruciform assembly 20 interconnecting first yoke 16 and second yoke 18 . First yoke 16 is bifurcated and includes a pair of laterally-spaced lugs 22 which are preferably symmetrical with respect to the rotary axis of first shaft 12 , as denoted by construction line A . Lugs 22 includes 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 . Second yoke 18 is bifurcated and includes a pair of laterally-spaced lugs 30 which are preferably symmetrical with respect to the rotary axis of second shaft 14 , as denoted by construction line B . Lugs 30 include an inboard surface 32 and an outboard surface 34 with an aperture 36 extending therebetween. Apertures 36 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 .

As best seen in FIGS. 2 and 3 , cruciform assembly 20 includes a cross member 38 having a central hub 40 from which a pair of first trunnions 42 A and a pair of second trunnions 42 B extend. First trunnions 42 A are orthogonal with respect to second trunnions 42 B, with all of the trunnions aligned within a common plane. First trunnions 42 A are cylindrical and are adapted for insertion into apertures 28 in lugs 22 of first yoke 16 so as to be axially aligned on first trunnion axis Y . Similarly, second trunnions 42 B are cylindrical and are adapted to be inserted into apertures 36 in lugs 30 of second yoke 18 so as to be axially aligned on second trunnion axis Z . Preferably, first trunnions 42 A and second trunnions 42 B are identical in size and shape. With first trunnions 42 A and second trunnions 42 B installed respectively in first and second yokes 16 and 18 , trunnion axes Y and Z pass through a common plane which orthogonally intersects the rotary axis of cruciform assembly 20 , as shown in FIG. 3 by construction line C .

Universal joint 10 also includes a first pair of bearing cup assemblies 46 A adapted to be mounted in apertures 28 and a second pair of bearing cup assemblies 46 B adapted to be mounted in apertures 36 . First bearing cup assemblies 46 A are provided for receiving and rotatably supporting first trunnions 42 A in apertures 28 . Similarly, second bearing cup assemblies 46 B are provided for receiving and rotatably supporting second trunnions 42 B in apertures 36 . Preferably, bearing cup assemblies 46 A and 46 B are identical. For purposes of brevity, the following description will be limited to the components of bearing cup assemblies 46 A with it understood that the corresponding components of bearing cup assemblies 46 B are substantially identical and, where necessary, are identified by common reference numeral with a B suffix.

Referring primarily to FIGS. 2 through 4 , each bearing cup assembly 46 A includes a bearing cup 48 A, a thrust washer 50 A, a set of roller bearings 52 A, a bearing retainer ring 54 A, and an elastomeric seal 56 A. Bearing cup 48 A is generally hollow and cylindrical in shape and has a cylindrical tubular segment 58 closed at one end by an end segment 60 . Tubular segment 58 of bearing cup 48 A defines an outer wall surface 62 adapted for retention in lug aperture 28 , and an inner wall surface 64 . Likewise, end segment 60 of bearing cup 48 A includes an outer end surface 66 and an inner end surface 68 . Roller bearings 52 A are disposed between inner wall surface 64 of tubular segment 58 and an outer wall surface 70 of trunnion 42 A so as to allow relative rotary movement between bearing cup 48 A and trunnion 42 A. Roller bearings 52 A are oriented to rotate on an axis parallel to axis A of trunnions 42 A and are arranged in a circumferential array about this axis. One end of each roller bearing is supported to roll against a bearing surface 72 formed on a raised circumferential flange segment 74 of thrust washer 50 A. The opposite end of roller bearings 52 A are supported to roll against a face surface of bearing retainer ring 54 A which, in turn, is retained in a circumferential groove 76 formed in inner wall surface 64 of bearing cup 48 A. Seal 56 A extends between outer wall surface 62 of bearing cup 48 A and outer wall surface 70 of trunnion 42 A to protect bearings 52 A against dirt and other contaminants and to retain the lubricant within bearing cup assembly 46 A. Once bearing cup assemblies 46 A are installed on first trunnions 42 A and inserted into lug apertures 28 , cross member 88 is centered and dynamically balanced. Thereafter, cruciform assembly 20 is secured to lugs 22 . A known method for securing cruciform assembly 20 includes mounting of snap rings 78 in circumferential grooves (not shown) formed in apertures 28 above outer end surface 66 of bearing cups 48 A. Alternatively, portions of outboard surface 26 of lugs 22 surrounding apertures 28 can be deformed (i.e., staked, peened, etc.) to create projections which engage outer end surface 66 of bearing cups 48 A. Still further, projections 80 A on lugs 22 can be deformed to entrap snap rings 78 against outer end surface 66 of bearing cups 48 A, as is disclosed in commonly-owned and U.S. application Ser. No. 09/189,886 filed Nov. 11, 1998, now U.S. Pat. No. 6,162,126 issued Dec. 19, 2000 entitled UNIVERSAL JOINT, the entire disclosure of which is hereby incorporated by reference.

Thrust washer 50 A is installed in bearing cup assembly 46 A between an end surface 82 of trunnion 42 A and inner end surface 68 of bearing cup 48 A. Thrust washer 50 A includes a disk segment 84 from which raised circumferential flange segment 74 extends. A central aperture 86 is formed through disk segment 84 and may correspond in size to the diameter of a lubricant passage 88 found in each trunnion 42 A and a circular reservoir 89 in bearing cup 48 A. As is conventional, a fitting (not shown) mounted on central hub 40 of cross member 38 communicates with lubricant passage 88 . The fitting is used to supply lubricant to passageway 88 for lubricating roller bearings 52 A as well as for providing a lubricant film between relatively movable surfaces. Disk segment 84 has an outer face surface 90 which faces and contacts inner end surface 68 of bearing cup 48 A. Likewise, disk segment 84 has an inner face surface 92 which faces and contacts end surface 82 of trunnion 42 A forming a substantially constant working area. Inner face surface 92 and outer face surface 90 are planar and parallel such that disk segment 84 has a constant thickness. In addition, thrust washer 50 A includes a circumferential inner wall surface 94 , as defined by flange segment 74 , which is adapted to face and contact outer wall surface 70 of trunnion 42 A. A chamfer surface 96 connects a circumferential outer wall surface 98 of flange segment 74 to outer face surface 90 of disk segment 84 .

As best seen from FIGS. 5 through 9 , thrust washer 58 A includes a series of lubrication grooves 100 which extend radially from central aperture 86 to inner wall surface 94 of flange segment 74 . Grooves 100 are arcuate in profile to define a cylindrical wall surface. It is preferable that an odd number of grooves 100 are provided and which are equally-spaced to define a like number of pie-shaped portions of disk segment 84 . In addition, a plurality of indentations or dimples 102 are formed on the pie-shaped portions of disk segment 84 . Dimples 102 can be randomly oriented or, more preferably, be aligned to define two circumferential rows. Dimples 102 are adapted to retain lubricant therein to provide continuous lubrication over a large area of trunnion end surface 82 . In addition, dimples 102 allow contaminants to be removed from the operating surfaces and collect therein.