AU644806B2

AU644806B2 - Undercut free constant velocity joint

Info

Publication number: AU644806B2
Application number: AU60611/90A
Authority: AU
Inventors: Werner Krude
Original assignee: GKN Automotive Inc
Current assignee: GKN Driveline North America Inc
Priority date: 1989-07-25
Filing date: 1990-06-22
Publication date: 1993-12-23
Anticipated expiration: 2010-06-22
Also published as: AU6061190A; EP0484420A4; CN1049050A; EP0484420A1; WO1991001453A1; JPH05501905A; BR9007553A; ES2024838A6; KR920704031A; CN1028665C; CA2016894A1

Description

WO 91/01453 C/U9/34 PCT/US90/03654 UNDERCUT FREE CONSTANT VELOCITY JOINT BACKGROUND OF THE INVENTTON I. Field of the Invention The present invention relates to a constant vteiocity universal joint for use in any application requiring torque transmission through a varying angle. More particularly, the invention involves a universa3 joint that utilizes a plurality of balls to transmit.9 a orquie from an inner joint member to an outer joint member. The interior of the outer joint member contains a in series of grooves that are in radial alignment with a complementary series of grooves that are positioned on the exterior of' the inner joint member. A cage is positioned hetween the outer joint member and the inner joint member to guid(. the balls as they traverse the grooves during articulation of the universal joint, 2. Description of the Prior Art The prior art reveals a wide variety of devices that permit the transmission of a rotational torque from one shaft that is angularly displaced with respect to another shaft coupled thereto. In general, most of the prior art devices require extensive machining of the individual parts to assure satisfactory assembly and operation of the device. Then, too, the overall strength of the prior art devices was compromised by the required machining of the individual parts.

The present invention differs from the undercut-free constant velocity joint that is shown and described in U.S. Patent No. 3,879,9630, entitled "Constant Velocity Joint" issued April 29, 1975, .to Hans-Heinrich Welschof et al. The constant velocity joint described in the above-referenced patent shows an outer joint member in which the individual b-all grooves are divergent with respect to the central axis of the universal joint, when viewed from the open end of the outer joint member. The ball grooves that are itioned in the inner joint member are convergent wtth r~spect to the central axis of the universal joint. The balls are maintained in a spaced apart planar I;WO 91/01453 C PCT/US90/03654 2 joint. The balls are maintained in a spaced apart planar relationship with one another by means of a cage that is positioned between the outer joint member and the inner joint member. The outer joint member does not lend itself to press forging techniques since the opening therein is of smaller diameter than the diameter of the interior cavity therein. Also, the lip of the outer joint member is thin because of the divergent nature of the ball grooves. The thin areas of the outer joint member occur at one of the areas of maximum stress in the universal joint, particularly when large angles of articulation are employed.

Thus, the present invention differs from the above-described universal joint in that the divergence and convergence of the ball grooves in the outer joint member and the inner joint member are in reverse order. Then, too, the free end of the outer joint member is of increased thickness in the present invention.

In U.S. Patent No. 4,188,803, entitled "Constant Velocity Universal Joint" issued February 19, 1980, to Nobuyuki Otsuka et al, there is shown a universal joint that employs an input and an output shaft. The output shaft has a cavity containing hub into which is fitted the end of the input shaft.

The input shaft contains an inner member attached thereto. The inside of the hub and the outside of the inner member contain ball grooves. A ball cage is positioned between the hub and the inner member. The ball cage is unique in that its inside and outside surfaces contain spherical surfaces that are eccentric instead of the usual concentric spherical surfaces. The ball cage is supported on spherical surfaces that are also eccentric.

The present invention utilizes ely concentric sfherical surfaces which -are easir to 4for. Further, the present invention does not have any undercuts that must be made in the hub area as does the above reference. The ball cage of the present invention is quite simple with concentric spherical surfaces being employed.

W;O 91/01453 PCT/US90/03654 3 Also, the hub and inner torque members-utilize concentric spherical surfaces.

Another example of the prior art is shown in U.S. Patent No. 4,B10,643, entitled "Rotary Constant Velocity Universal Joint" issued September 9, 1986, to Werner Krude. The universal joint shown in the patent 4,610,643 has an outer joint member in which the ball grooves are convergent as viewed from the open end of the outer joint member and the grooves in the inner joint member are divergent. This arrangement or slope of the grooves is just the opposite to that seen in the previously discussed patent 3,879,960. The outer joint member is separate from the axle-hub combination with which it coacts. A cylindrical sleeve unites the outer joint member to the hub by welding and crimping techniques.

A ball cage supporting elemert is used to retain ths balls in the grooves to engage the balls on one side. The ball cage supporting element does not contact the spherical surfaces of the outer joint member or the inner joint member, but inscead, the ball cage contacts a spherical surface 30 in the interior of the joint near the central hub as shown in Figure 1. In the above-described patent, the ball cage contains a series of fingers that are intercalated with respect to the balls. This universal joint requires extensive machining to fabricate the joint as well as complicated tools for fabricating the various details.

The present invention is an improvement over the universal joint shown and described in the patent 4,610,643, in that fewer parts are utilized and there is less frictional contact with the ball cage. Additionally, the present invention provides a ball cage with apertures therein that completely circumscribe, each ball. Further, by providing a universal joint with an outer joint member having a thick structural section near its open end, the area of highest load concentration upon articulation, the joint is more reliable and durable. The outer joint member fabrication is simplified and the cost of fabrication i significantly reduced.

I I 1 3a SUMMARY OF THE PRESENT INVENTION The invention comprises a constant velocity universal joint for use between a driven shaft and driving shaft for transmission of power from said driving shaft to said driven shaft, said constant velocity universal joint comprising: an inner joint member having a first planar end, a second planar end spaced from said first planar end and an exterior spherical surface between said first and second planar ends, said inner joint member further having an axis of symmetry normally disposed to said first and second planar ends, and an aperture located about said axis of symmetry; drive means integral with one of said driven and driving shaft and said aperture to rotate said inner joint member; a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface of said inner joint member; an annular outer joint member surrounding said inner joint member, said annular outer joint member having one end, an opposite end, an interior spherical surface extending continuously between said one end and said opposite end, and a central aperture defined by said interior spherical surface of said annular outer joint member, said outer joint member further having a centrally positioned axis therethrough; a second plurality of longitudinally extending circumferentially spaced ball races formed in said interior spherical surface of said annular outer joint member, each ball race of said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member being aligned with an associated one of said first plurality of longitudinally extending circumferentially spaced ball races of said inner joint member;

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Ar 0 3b a plurality of spherical balls disposed in said first plurality of longitudinally extending circumferentially spaced ball races of said inner joint member each one of said plurality of spherical balls further extending into a respective one of said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member to provide a driving engagement between said inner and said annular outer joint members; cage means interposed said inner joint member and said annular outer joint member, said cage means having an outer spherical surface in intimate contact with said interior spherical surface of said annular outer joint member; an inner spherical surface in intimate contact with said exterior spherical surface of said inner joint member; and a plurality of apertures, equal in number to said first and second longitudinally extending circumferentially spaced ball races, interposed between said outer spherical surface and said inner spherical surface for receiving each of said plurality of spherical balls; each ball race of said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member defining a longitudinally S. extending path along which the said spherical balls are adapted to run, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle, said linear part being adjacent said opposite end of said annulr outer joint member and said circular arc part being at said one end of said annular outer joint member such that as each of said plurality of 30 spherical balls move along said second plurality of longitudinally extending circumferentially spaced ball races from said opposite end of said annular outer joint member towardsom said opposite end of said annular outer joint member towards said one end of said annular outer Joint member, each of said plurality of spherical balls traverse along said linear part of said second plurality of longitudinally extending circumferentially spaced ball

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3c crc.lmo.r- crcc po-r+ races to said -netinal conv-rging part-pherial ee. of said second plurality of longitudinally extending circumferentially spaced ball races; and a hub attached to said opposite end of said annular outer joint member, said hub having a centrally positioned cavity mating with said otion partc lindrical urf -of said second plurality of longitudinally extending circumferentially spaced ball races of said annalar outer joint member.

Preferably the said drive means comprises: a first plurality of splines located within said aperture of said inner joint member; and wherein one of said driven and driving shafts comprises: an input shaft having a second plurality of splines on one end thereof, said first and second plurality of splines connecting one of said driven and driving shafts to said inner joint member for rotation therewith; and further wherein said other of said driven shaft and driving shaft comprises: an output shaft formed on an integral part of said hub, said output shaft having an axis coincident with said centrally positioned axis of said annular outer joint member.

It is also preferred that the said cage means interposed said inner joint member and said annular outer joint member is an annular ball cage having a central aperture and a central axis and said plurality of apertures of said cage means are of an even number, each aperture containing one of said spherical balls.

It is further preferred that said first plurality of longitudinally extending circumferentially spaced ball races in said inner joint member have a minimum radial distance from said axis of symmetry of said inner joint member adjacent to said hub wherein each of said first plurality of longitudinally extending circumferentially spaced ball races are comprised of a curved section and a linear section, while said second plurality of longitudinally extending circumferentially spaced ball races in said annular outer 3d joint member have a maximum radial distance from said centrally positioned axis of said annular outer joint member adjacent to said hub wherein each of said second plurality of longitudinally extending circumferentially spaced ball races are comprised of a curved section and a linear section.

In one preferred embodiment the constant velocity universal joint comprises: an inner joint member having an axis of symmetry, an exterior spherical surface, a central splined aperture concentric with said axis of symmetry, and a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface; each ball race of said first plurality of longitudinally extending circumferentially spaced ball races defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle; drive means having a plurality of external splines adapted to be received in seid central splined aperture of "said inner joint member; an annular outer joint member having a central axis, one end, an opposite end, an interior spherical surface extending continuously between said one end and said opposite end, and a centrally positioned aperture therethrough, said annular outer joint member being Spositioned in surrounding relationship to said inner joint member, said annular outer joint member further having a second plurality of longitudinally extending 30 circumferentially spaced ball races formed in said interior e* "spherical surface, each of said second plurality of longitudinally extending circumferentially spaced ball races defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle; a plurality of spherical balls located in said first s and second plurality of longitudinally extending circumferentially spaced ball races of said inner and 3e annular outer joint members; an annular ball cage member interposed said inner joint member and said annular outer joint member for.the containment of said plurality of spherical balls, said annular ball cage member having an outer spherical surface in intimate contact with said interior spherical surface of said annular outer joint member, an inner spherical surface spaced from said outer spherical surface in intimate contact with said exterior spherical surface of said inner joint member, a centrally positioned aperture, and a plurality of circumferentially spaced radially aligned apertures, equal in number to said first and second plurality of longitudinally extending circumferentially spaced ball races, between said inner and outer spherical surfaces for receiving one each of said plurality of spherical balls; a hub attached to one end of said annular outer joint member, said hub having a centrally positioned cavity therein; said exterior spherical surface of said inner joint member being a greater radial extent from said axis of symmetry than said first plurality of longitudinally extending circumferentially spaced ball races; and said interior spherical surface of said annular outer joint member being of lesser radial extent from said central axis than said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member.

In another preferred embodiment the constant velocity universal joint comprises: an inner joint member having an axis of symmetry, an exterior spherical surface, a central splined aperture concentric with said axis of symmetry, and a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface, said first plurality of longitudinally extending circumferentially spaced ball races having a minimum radial distance from said 3f axis of symmetry, each ball race defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle, said exterior spherical surface of said inner joint member being of greater radial extent from said axis than said first plurality of longitudinally extending circumferentially spaced ball races; drive means having a plurality of external splines adapted to be received in said central splined aperture of said inner joint member; an annular outer joint member having a central axis, one end, an opposite end, an interior spherical surface extending continuously between said one end ard said opposite end and a centrally positioned aperture therethrough, said annular outer joint member being positioned in surrounding relationship to said inner joint member, said annular outer joint member further having a second plurality of longitudinally extending circumferentially spaced ball races formed in said interior spherical surface, said second plurality of longitudinally Sextending circumferentially spaced ball races having a 4q11 S. maximum radial distance from said central axis, each ball race defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an aru of a circle, said annular outer joint member further having a greater wall thickness on said opposite end, said interior Sspherical surface being of lesser radial extent from said central axis than said second plurality of longitudinally 30 extending circumferentially spaced ball races; an annular ball cage member interposed said inner joint member and said annular outer joint member for the containment of a plurality of spherical balls, said annular ball cage member comprising an outer surface, an inner 35 surface spaced from said outer surface, a centrally positioned aperture and a plurality of circumferentially 1 3g spaced radially aligned apertures of even number arranged in diametrically opposite pairs perpendicular to said central axis, said plurality of circumferentially spaced apertures each containing a spherical ball, each said spherical ball being in contact with said first and second plurality of longitudinally extending circumferentially spaced ball races of said inner joint member and said outer joint member, respectively, said outer surface and said inner surface of said annular ball cage member being spherical surfaces that are concentric with one another; and a hub attached to said one end of said annular outer joint member, said hub having a centrally positioned cavity therein.

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WO 91/01453 PC/US90/03654 4 The pre ent invention is a constant velocity universal joint for use in t nsmitting a driving torque from a first axial direction to another axial direction, angularly disposed with respect to the first d'rection.

The invention 'ncludes on outer joint member that contains a plurality of a 'ally extending grooves therein. An inner joint member is posit oned within the outer joint member and a plurality of mutually depen ent grooves are carried by the inner and outer joint members. The oter joint member is coupled to a hub that is formed as an integra part of a first torque transmitting shaft and a pluralify of balls are held in planar relationship to one another by a cag that is positioned between and in contact with the outer and inne joint members. A second torque shaft is coupled to the inner jol t member by any A primary object of the present invention is to provide a universal joint that requires a minimum amount of machining in the manufacture thereof.

Another object of the present invention is to provide a universal joint in which the major components are undercut-free.

A further object of the present invention is to provide a design that lends itself to cold impact press forming of the parts of the universal joint.

Another object of the present invention is to reduce the contact area of the ball cage with the outer joint member and the inner joint member of the universal joirt.

Still another object of the present invention is to provide a universal joint with enhanced strength characteristics.

A further object of the present invention is to provide a universal joint that is easy to assemble and disassemble.

Further objects and advantages of the present invention will become apparent from the following description and the appended claims, reference being made to the accompanying drawings i 2 s\ WO 91/01453 PCT/US9O/03654 forming a part of this specification, wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a part sectional view of a prior art undercut-free outer joint member; Figure 1B is a graphical representation cf the prior art under-cut free constant velocity joint forces experienced in the ball track as the bending angle increases.

Figure 1 is a part sectioned side view that shows the universal joint of the present invention; Figure 2 is a part sectioned side view that shows the universal joint in an angular drive attitude; Figure 3 is a part sectioned side elevational view of the integral hub and output shaft; Figure 4 is an end view of the hub and output shaft as viewed along lines 4-4 of Figure 3; Figure 5 is an elevational end view of the outer joint member that shows the pairs of grooves positioned on the interior surface thereof; Figure 6 is a sectioned view taken along section lines 6-6 of Figure 5 which shows the curvilinear surfaces for the balls and the cage; Figure 7 is an end view of the inner joint member that shows the pairs of grooves positioned on the exterior surface of the inner joint member; and Figure 8 is a sectioned view taken along section lines 8-8 of Figure 7 that shows the curvilinear surfaces for the balls and the cage.

It is to be understood that the present invention is not limited to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways within the scope of the claims. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

SUBSTITUTE SHEET WVO 91/01453 PCT/US90/03654 6 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and-more particularly to Figure 1A, there is illustrated a prior art undercut-free constant velocity univer sl joint in part section view that has application for many uses such as the coupling of drive shafts and other applications. The graph illustrated in Figure 1B represents the forces experienced in the outer joint member as the bending angle increases. The bending is the angle of articulation between the central axis of the outer joint member and the central axis of the inner joint member. The graph clearly shows that the greatest forces are experienced at maximum bending angleand in the area near the open end of the outer joint member.

Figure 1 is a part sectioned side elevational view that shows the universal joint of the present invention. The overall apparatus is identified by the numeral 10 as shown. For purposes of illustration it will be assumed that a rotational force or torque is applied to an input shaft 12 which is shown at the right-hand side of figure 1. An output shaft 14 is positioned at the left-hand side of the overall apparatus 10. Of course, the flow of torque could be in a direction opposite to that above stated. The output shaft 14 is coupled to a hub 16 that can be, as shown, til integral part of the output sh.ft 14. The hub 16 and the output shaft 14 are coaxial along an output axis 20. An input axis 18 is shown coincidental with the output axis 20. The hub 16 has a cylindrical external surface 22 that abuts a radially inward lip 24. The lip 24 is planar and is perpendicular to the output axis 20. The hub 16 has a concavity that is formed by an arcuate section 26, a frustoconical section 28, and a spherical section The blending together of the above three sections produces a concavity that can be readily formed by press and forge 4 techniques.

An outer joint member 32 has an exterior surface 34 that is cylindrical about the output axis 20. The left-hand end of the outer joint member 32, as viewed in Figure 1, has an internal SUBSTITUTE SHEET WO 91/01453 W091/1453PCr/US9O/03654 7 cylindrical surface 36 of shorter radius than the exterior surface 34. The internal cylindrical, surface 36 of the outer joint member 32 coacts with the cylindrical external surface 22 of the hub 16 in order to couple the hub 16 and the outer joint member 32 in a real Cve.-o ;"ace2 manner to be more fully described hereinafterL The outer joint member 32 has an interior spherical surface 38. The interior spherical surface 38 is defined by a radius that has its locus situated on the input axis 1B at a point L. The left-hand end of the outer joint member 32 Is planar in configuration and has a radial extent spanning the distance between the internal cylindrical surface 36 and the interior spherical surface 38. The juncture between the end 40 and the interilor spherical surface 38 can be beveled as identified by the number 42. The right-hand end 44 of the outer joint member 32 has a planar configuration and has a radial extent that extends between the exterior surface 34 and the interior spherical surface 38. The juncture between the end 44 and the interior spherical surface 38 is beveled at approximately 450 as will be commented on elsewhere. Thus, it is evident that a large cavity passes through the central axial region of the outer joint member 32.

A plurality of axially extending arcuate ball r~t.es or grooves 46 1-tcut into and through the interior spherical surface 38 of the outer joint member 32, The mid line or, the most radially outward extent of' each ball race has a circular section 48 that is coupled to an essentially linear section 50. The circular section 48 has a radius with a locus that is positioned on the output axis 20 to the left of the point L. The ball. races 46 are positioned diametrically with respect to each other as is shown in Figure 5. Each pair of diametrically opposed ball races 46 has their mid lines lying in a plane that also cntains the output axis An inner joint member 52 Is positioned within the open cavity that passes through the outer Joint member 32. The inner joint member 52 is po Hioned symmetrically about the input. axis WO 91/01453 WO 9101453PCr/US90/03654 18. The inner joint member 52 has an internal cylindrical bore 54 that is equipped with axially extendIng splines 56. The inner joint member 52 has radially extending left and right-hand essentially planar ends 58 and 60. The most radial exterior surface 62 of the inner joint member 52 is spherical in configuration with the spterical extent terminating at. the juncture -with the planar ends 58 and The inner Joint member 52 contains a plurality of axially extending arcuate ball races or grooves 64 that are cut into and through the exterior spherical surface 62. The mid line or, the most radial inward extent of each ball race 64 has a circular section 66 that is conn~cted to an essentially linear section 68. The circular section 6S has n radius with a locus that is positioned on the input axis 18 to the right of' the point L. The distance of the locus of the circular section 66 from the point L should be essentially equal to the distance of the locus of the circular section 48 of the outer joint member from the point L.

L2- I- c is s1 atnedr withn'i ito'th outer joint member 32 and is spaced exteriorly of he inner joint member 52 in telescoped arrangement. The ball cage 70 has exterior and interior spherical surfaces 72 rid 74 that are concentric with one another. The exteri spherical surface 72 is terminated at its left-hand. end, as v' wed in Figure Is by a radially inwardly extending end 76 The most radially inward portion of the end 76 intersect an axially extending cylindrical bore 78. The cylindrical bar terminates at its right-hand end with an intersection with e interior spherical surface 74. The exterior spherioal surf ce 72 of the bal cage 70 terminates at its right-hand end b a radially inwaxdly extending end 80. The most radially mnw d portion of the end 80 intersects an axially extending cyli rical bore 82. The cylindrical bore 8q. terminates at its left and end with an intersection with the intarior Sobrn 4 8a A ball cage 70 is positioned within the cavity of the outer joint member 32 and is spaced exteriorly of the inner joint member 52 in pivotable arrangement. The.ball cage has exterior and inturior spherical surfaces 72 and 74 in offset relationship to each other but concentric with one another. The exterior spherical surface 72 is terminated at its left-hand end, as viewed in Figure 1, by a radially inwardly extending end 76. The most radiclly inward portion of the end 76 intersects an axially extending cylindrical bore 78. The cylindrical bore terminates at its right-hand end with an intersection with the interior spherical surface 74. The exterior spherical surface 72 of the ball cage 70 terminates at its right-hand end by a radially inwardly extending end S 15 The most radially inward portion of the end 80 intersects an axially extending cylindrical bore 82. The cylindrical bore 82 terminates at its left-hand end with an intersection with h the interior spherical surface 74.

V i 'a a a a a1 q'a 9 The exterior spherical surface 72 of the ball cage is in rotational contact with the interior spherical surface 38 of the outer joint member 32. In a similar manner, the interior spherical surface 74 of the ball cage is in rotational contact with the exterior spherical surface 62 of the inner joint member 52.

A plurality of radially extending circumferentially spaced bores or windows 84 equal in number to the groove pairs are provided through the wall created by the exterior and interior spherical surfaces 72 and 74 of the ball cage 70. The axes of the bores 84 pass through the point L on the input shaft 12. Each axis of bores 84 is coincident with the mid line of the ball races 46 and 64.

In other words, the axis of each bore 84 lies in a plane 15 that contains the mid lines of each pair of mid lines associated with the ball races 46 and 64.

A spherical ball 86 is positioned within the confinement of each bore 84 so that it can translate simultaneously along the mid lines of the ball races 46 20 and 64.

The input shaft 12 has externally protruding splines 88 that mesh with the splines 56 that extend axially along the cylindrical bore 54 of the inner joint member 52.

The cylindrical bore 54 of the inner joint member 52 contains a reentrant groove 90 for the containment of a fingerlock retaining ring 92. A plurality of cantilevered resilient fingers 94 snap over a radially disposed ledge 96 that circumscribes the input shaft 12. Thus, the fingerlock retaining ring 92 prevents axial movement of the input shaft 12 with respect to the inner joint member 52.

Figure 2 is a part sectioned side view of the overall apparatus 10' that shows the universal joint in an angular drive attitude. For purposes of discussion, the output shaft 14, the attached hub 16 and the outer joint member iP., 9a 32 remain in fixed relationship to one another and do not move, other than rotatively. As depicted in Figure 2, the input shaft 12 has assumed a position so that its input axis 18 is angularly disposed 9 9 8 8 9 *9r~ *898 9 9.

8 8 8 99*8 99 49 8 9 9 8 9 889.

9e *9 999*88 9 9.

WO 91/01453 PCTIUS90/03654 with respect, to the output axis 20 of .the output shaft 14. As the input shaft 12 moves to a new angular position, the inner joint.

member 52 also moves through the same angle since it is fixed with respect to the input shaft 12. As the input shaft 12 moves hrough a given angle, the spherical balls 86 translate along the most vertically oriented spherical ball 86 moves the furthest to the right while the lowest diametrically positioned spherical ball R6 moves correspondingly to the left. along another pair of ball races 46 and 64. The remaining spherical balls 86 move correspondingly along the ball races 46 and 64. Of course, if a pair of spherical balls 86 lies on the input axis 18, there would be no translation along the ball'races 46 and 64. The above discussion assumes that there is no rotation of the input and output shafts 12 and 14.

As the input shaft 12 and the inner joint member 52 articulate through a given angle, the ball cage 70 rotates a lesser amount as can be seen in Figure 2. It is important that the ball cage 70 always articulates so that the axis 98 of the bores 84 remains positioned so that the point L lies thereon. In this manner, a const!nnt velocity will be achieved through the overall apparatus An examination of the lower spherical ball '6 in Figure 2 shows that it has moved to thp left until it is in close proximity to the arcuate section 26 of the hub 16. Also, the lowermost portion of the ball cage 70 has moved to the left until it occupies part of the cavity defined by the frustoconical section 28. The ball cage 70 has contact with only the spherical balls 86, the interior spherical surface 38 of the outer joint member 32, and the exterior spherical surface 72 of the inner joint member 52.

The angular movement of the input shaft 12 is terminated when the input shaft 12 contacts a frustoconical beveled surface 100 of the outer joint member 32.

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WO 91 0453 PCT/US90/03654 11 Figure 3 is a part sectioned aide elevational view of the integral hub 16 and the output shaft 14. The output shaft 14 can be divided into cylindrical axial extents .102 and 104, each containing an arcuate array of longitudinally aligned splines 106.

The hub 16, which is an extension of the output shaft 14, has an internal cavity defined by the arcuate section 26, the frustoconical section 28, !nd the spherical section 30. Since there is no undercutting required in the formation of the internal cavity of the hub 16, it can be formed by press or forging techniques.

Figure 4 is an end view of the hub cavity as viewed along lines 4-4 of Figure 3. The lip 24 is shown in its planar view along with the lines of intersection between the previously mentioned surfaces of the cavity within the hub 16.

Figure 5 is an ele4atenal- end view of the outer joint member 32 that shows the diametrically opposed pairs of grooves positioned on the interior spherical surface 38 of the outer joint member 32. As can be seen, the ball races 46 are not undercut; thus, they can be formed by press or forge techniques. If sintering techniques are employed in the fabrication of the outer joint member 32 then metal removal techniques need not be employed to form the spherical interior surface 38. The cross-sectional configuration of the ball race 46 is shown as circular with tangential parallel extensions 108 coupled thereto. While the extensions 108 are shown as parallel, they may, if desired, diverge slightly toward the input axis 18. Also, the arcuate cross-sectional portion of the ball race 46 can be slightly non-circular, providing for line contact with the spherical balls that translate therethrough. S"ye Fivure 6 is a sectionalkviea taken along section lines 6-6 of Figure 5 that shows the curvilinear surface of the circular and linear sections 48 and 50. The interior spherical surface 38 is also shown.

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WO091/01453 PfU9/35 PCT/US90/03654 12 Figure 7 is an end view of the inner joint member 52 that shows the pairs of diametrically opposed ball races 64 positioned on the exterior spherical surface 62 of the inner joint member 52. The number of ball races 64 equals the number of ball races 46 as previously shown in Figure 5. The cylindrical bore 54 contains the splines 56 which are in axial alignment, with the input axis 18.

Figure 8 is a sectional view taken along section lines B-8 of Figure 7 that shows the curvilinear mid line of the ball race 64 and the exterior spherical surface 62 of the inner joint member 52. The planar left aitd right ends 58 and 60 permit the employment of easy fabrication t~chniques as previously commented on.

ASSEMBLY AND OPERATION The assembly of the overall apparatus 10 of the present invention is very straightforward. Also, the geometry of the components of the overall apparatus 10 permit automated assembly.

The inner joint member 52 is positioned so that its left-hand edge, as viewed in Figure 1, is facing up. Next, the ball cage is lowered concentrically, and in axial alignment, around the inner joint member 52 until the bores 84 are opposite the circular section 66 of the ball race 64. The spherical balls 86 are then inserted into each of the bores 84. As the spherical balls 86 move radially inward, they will contact the circular section 66 of' the ball race 64 and remain stationary. The outer joint member 32 is then telescoped over the ball cage 70. The ball cage 70 is then moved into final nxia) alignment. The spherical halls 86 are now held against radially outward disengagement by the ball races 46. The cylindrical external surface 22 of the hub 16 is then moved into engagement with the internal cylindrical surface 36 of the outer joint member .32 and then immobilized therewithin. Thp immobilization technique can involve a press fit, welding, or a snap ring. =4noempAas depltedt.4f2. ini Figuire 2. At this time or subsequent thereto) the input shaft 12 can be inserted into the WO 91/01453 W091/1453PCr/US90/03654 13 cylindrical bore 54 so that the splines 56 and 88 slide into engagement. Upon full insertion of the input shaft 12, the resilient fingers 94 of the previously inserted retaining ring 92 engage with the ledge 96 on the input shaft 12, locking it into its final position.

During operation of the overall apparatus 10, a. torque is applied to the input shaft 12, causing it and the spline coupled inner joint member 52 to rotate. The torque is then transmitted from the inner joint member 52 to the spherical balls 86 by contact with the ball races 64. The spherical balls 86 then transmit the torque to the outer joint member 32 via the ball races 46. Since the outer joint member is non-rotatively attached to the lip 24 of the hub 16, the hub 16 rotates along with the integrally attached output shaft 14.

When the input and output axis 18 apd 20, respectively, are in alignment with one another, the spherical balls 86 will remain at one location along the ball races 46 and 64 during rotation of the overall apparatus 10. Since the spherical balls are centrally positioned within the ball races 46 and 64, the stresses are fairly well distributed through the outer joint member 32 and the inner joint member 52.

its the input shaft 12 and its accompanying input axis 18 assume an angular position or bending angle, sujch as 4.90, with respect to the output shaft 14 and its output axis 20, *the spherical, balls 86 no longer track in a single circular path about the input axis 18s. During one complete revolution of the overall apparatus 30, thp spherical balls 86 will traverse nearly the entire length of the ball races 46 and 64. Since the spherical balls 86 are fixed against lateral movement with respect to the ball cage 70, the ball cage 70 not. onl'y rotates on its exterior and interior spherical surfaces 72 and 74 but, also, the ball cage must rotate when the input axis 18 shifts position from left to right about an axis that passes through the point L. The rotational axis for tht ball cage 70 is perpendiwlar t~o the input WO 91/01453 PCTrUS90/0354 14 axis 18 only when the input, and output axes 18 and 20 are in alignment. The amount and frequency of the rotation of the ball cage 70 about its axis depends on the frequency and magnitude of the change in the angle as identified in Figure 2 by reference numeral 110. When the overall apparatus 10 is operating at a maximum bending angle, a maximum load occurs against the inside surface of the circular section 48 adjacent to the end 44 of the outer joint member 32. This point of maximum loae is identfied by numeral 112 in Figure 2. Since the design of the outer joint member 32 is thickest at the end 44, it can withstand the high loads induced at the maximum load point 112. Then, too, the increased overall cross-section of the outer joint member 32 at the end 44 reduces the amount of detection of the end 44 in a circumferential or hoop direction. The reduced circumferential elongation results in longer life and increased durability of the overall apparatus.

While the illustrative embodiment of the invention has been described in considerable detail for the purpose of setting forth a practical operative structure whereby the invention may be practiced, it is to be understood that the particular apparatus described is intended to be illustrative only, and that the various novel characteristics of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention defined in the appended claims.- hat i- -clnimod ic:-- -p.

\7 '1.

Claims

1. A constant velocity universal joint for use between a driven shaft and driving s!,haft for transmission of power from said driving shaft to said driven shaft, said constant velocity universal joint comprising: an inner joint member having a first planar end, a second planar end spaced fro~n said first planar end and an exterior spherical surface between said first and second planar ends, said inner joint member further having an axis of symmetry normally disposed to said first and second planar ends, and an aperture located about said axis of symmetry; drive means integral with one of said driven and driving shaft and said aperture to rotate said inner joint member; a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface of said inner joint member, each ball race defining a longitudinally extending path, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle; 20 an annular outer joint member surrounding said inner joint member, said annular outer joint member having one end, an $its opposite end, an interior spherical surface extending continuously between said one end and said opposite end, and a central aperture defined by said interior spherical surface of said annular outer joint member, said outer joint member further

4.f having a centrally positioned axis therethrough; a second plurality of longitudinally extending circumferentially spaced ball races formed in said interior so"t spherical surface of said annular outer joint member, each ball 30 race of said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member being aligned with an associated one of said first plurality of longitudinally extending circumfezentially spaced ball races of said inner joint member; a plurality of spherical balls disposed in said first 15a plurality of longitudinally extending circuxnferentia~~ 'aced ball races of said Thner joint member each one of saL. plurality of spherical balls further extending into a respective one of S S. S S S S tSe* S *55* C C S CS S~ S S 5*55 C S S SC.. S C S*S S* S C C C CC S C S I, 16 said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member to provide a driving engagement between said inner and said annular outer joint members; cage means interposed said inner joint member and said annular outer joint member, said cage means having an outer spherical surface in intimate contact with said interior spherical surface of said annular outer joint member, an inner spherical surface in intimate contact with said exterior spherical surface of said inner joint member; and a plurality of apertures, equal in number to said first and second longitudinally extending circumferentially spaced ball races, interposed between said outer spherical surface and said inner spherical surface for receiving each of said plurality of spherical balls; each ball race of said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member defining a longitudinally extending path along which the said spherical balls are adapted to run, which path is S. 20 in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle, said linear part being adjacent said opposite end of said annular outer joint member and said circular arc part being at said one end of said annular outer joint member such that as each of said plurality of S" 25 spherical balls move along said second plurality of longitudinally extending circumferentially spaced ball races from said opposite end of said annular outer joint member towards said one end of said annular outer joint member, each of said plurality of spherical balls traverse along said linear part of 30 said second plurality of longitudinally extending S circumferentially spaced ball races to said circular arc part of said second plurality of longitudinally extending circumferentially spaced ball races; and a hub attached to said opposite end of said annular outer joint member, said hub having a centrally positioned cavity 17 mating with said linear parts of said secc.id plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member. 2. The constant velocity universal joint of claim 1 wherein said drive means comprises: a first plurality of splines located within said aperture of said inner joint member; and wherein one of said driven and driving shafts comprises: an input shaft having a second plurality of splines on one end thereof, said first and second plurality of splines connecting one of said driven and driving shafts to said inner joint member for rotation therewith; and further wherein said other of said driven shaft and driving shaft comprises: an output shaft formed on an integral part of said hub, said output shaft having an axis coincident with said centrally positioned axis of said annular outer joint member. 3. The constant velocity universal joint of claim 1 wherein said cage means interposed said inner joint member and said annular outer joint member is an annular ball cage having a central aperture and a central axis. 4. The constant velocity universal joint of claim 3 -wherein said plurality of apertures of said cage means are of an even number.

5. The constant velocity universal joint of claim 4 wherein said plurality of apertures of said cage means are arranged in .diametrically opposite pairs perpendicular to said central axis of said central aperture of said cage means.

6. The constant velocity universal joint of claim 1 wherein each of said apertures of said plurality of apertures of said cage means contains one of said spherical balls.

7. The constant velocity universal joint of claim 1 wherein •said first plurality of longitudinally extending circumferentially spaced ball races in said inner joint member have a minimum radial distance from said axis of symmetry of said inner joint member adjacent to said hub. 18

8. The constant velocity universal joint of claim 1 wherein said second plurality of longitudinally extending circumferentially spaced ball races in said annular outer joint member have a maximum radial distance from said centrally positioned axis of said annular outer joint member adjacent to said hub.

9. The constant velocity universal joint of claim 1 wherein said exterior spherical surface of said inner joint member is of greater radial extent from said axis of symmetry of said inner joint member than said first plurality of longitudinally extending circumlferentially spaced ball races contained therein, and wherein said interior spherical surface of said annular outer joint member is of lesser radial extent from said centrally positioned axis of said annular outer joint member than said second plurality of longitudinally extending circumferentially spaced ball races contained therein. The constant velocity universal joint of claim 9 wherein said exterior spherical surface of said inner joint member and said interior spherical surface of said annular outer joint 20 member are concentric with one another.

11. A constant velocity universal joint for use between a driven to ;shaft and a driving shaft for transmission of power from said driving shaft to said driven shaft, said constant velocity universal joint comprising: an inner joint member having an axis of symmetry, an exterior spherical surface, a central splined aperture concentric :with said axis of symmetry, and a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface; 30 each ball race of said first plurality of longitudinally "extending circumferentially spaced ball races defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle; drive means having a plurality of external splines adapted 19 to be received in said central splined aperture of said inner joint member; an annular outer joint member having a central axis, one end, an opposite end, an interior spherical surface extending continuously between said one end and said opposite end, and a centrally positioned aperture therethrough, said annular outer joint member being positioned in surrounding relationship to said inner joint member, said annular outer joint member further having a second plurality of longitudinally extending circumferentially spaced ball races formed in said interior spherical surface, each of said second plurality of longitudinally extending circumferentially spaced ball races defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the taid axis of symmetry and in another part is an arc of a circle; a plurality of spherical balls located in said first and second plurality of longitudinally extending circumferentially spaced ball races of said inner and annular outer joint members; an annular ball cage member interposed said inner joint 20 member and said annular outer joint member for the containment of said plurality of spherical balls, said annular ball cage member i ;having an outer spherical surface in intimate contact with said interior spherical surface of said annular outer joint member, an inner spherical surface spaced from said outer spherical surface in intimate contact with said exterior spherical surface of said inner joint member, a centrally positioned aperture, and a plurality of circumferentially spaced radially aligned apertures, equal in number to said first and second plurality of longitudinally extending circumferentially spaced ball races, 30 between said inner Pnd outer spherical surfaces for receiving one each of said plurality of spherical balls; a hub attached to one end of said annular outer joint member, said hub having a centrally positioned cavity therein; said exterior spherical surface of said inner joint member being a greater radial extent from said axis of symmetry than said 20 first plurality of longitudinally extending circumferentially spaced ball races; and said interior spherical surface of said annular outer joint member being of lesser radial extent from said central axis than said second plurality of longitudinally extending circumferentially spaced ball races of said annular outer joint member.

12. The constant velocity universal joint of claim 11 wherein said plurality of circumferentially spaced apertures in said annular ball cage member are of an even number.

13. The constant velocity universal joint of claim 12 wherein sai< plurality of circumferentially spaced apertures are arranged in diametrically opposite pairs perpendicular to a central axis of said centrally positioned aperture.

14. The constant velocity universal joint of claim 11 wherein said annular ball cage member has interior and exterior spherical surfaces that are concentric with one another. The constant velocity universal joint of claim 11 wherein said first plurality of longitudinally extending circumferentially spaced ball races in said inner joint member have a minimum radial distance from said axis of symmetry of said inner joint member.

16. The constant velocity universal joint of claim 11 wherein said second plurality of longitudinally extending circumferentially spaced ball races in said annular outer joint member have a maximum radial distance from said central axis of said annular outer joint member.

17. The constant velocity universal joint of claim 11 wherein said exterior spherical surface of said inner joint member and said interior spherical surface of said annular outer joint .member are concentric with each other.

18. The constant velocity universal joint of claim 11 wherein said hub and said outer annular joint member are united by a snap ring.

19. The constant velocity universal joint of claim 11 wherein j*% 21 said annular outer joint member has a greater wall thickness on an opposite end most remote from said hub. The constant velocity universal joint of claim 11 wherein a retaining ring is interposed said inner joint member and said drive means.

21. A constant velocity universal joint for use between a driven shaft and a driving shaft for transmission of power from said driving shaft to said driven shaft comprising: an inner joint member having an axis of symmetry, an exterior spherical surface, a central splined aperture concentric with said axis of symmetry, and a first plurality of longitudinally extending circumferentially spaced ball races formed in said exterior spherical surface, said first plurality of longitudinally extending circumferentially spaced ball races having a minimum radial distance from said axis of symmetry, each ball race defining a longitudinally extending path for spherical balls, which path is in one part linear and parallel to the said axis of symmetry and in another part is an arc of a circle, said exterior spherical surface of said inner joint member being of 20 greater radial extent from said axis than said first plurality of longitudinally extending circumferentially spaced ball races; drive means having a plurality of external splines adapted to be received in said central splined aperture of said inner joint member; an annular outer joint member having a central axis, one end, an opposite end, an interior spherical surface extending continuously between said one end and said opposite end and a centrally positioned aperture therethrough, said annular outer joint member being positioned in surrounding relationship to said 30 inner joint member, said annular outer joint member further 9*s having a second plurality of longitudinally extending circumferentially spaced ball races formed in said interior spherical surface, said second plurality of longitudinally extending circumferentially spaced ball races having a maximum radial distance from said central axis, each ball race defining a 22 longitudinally extending path for spherical balls, which path is in One part linear and parallel to the said axis of symmetry and in another part is an arc of a circle, said annular outer joint member further having a greater wall thickness on said opposite S end, said interior spherical surface being of lesser radial extent from said central axis than said second plurality of loogitudinally extending circumferentially spaced ball races; an annular ball cage member interposed said inner joint member and said annular outer joint member for the containment of a plurality of spherical balls, said annular ball cage member comprising an outer surface, an inner surface spaced from said outer surface, a centrally positioned aperture and a plurality of circumferentially spaced radially aligned apertures of even number arranged in diametrically opposite pairs perpendicular to said central axis, said plurality of circumferentially spaced apertures each containing a spherical ball, each said spherical ball being in contact with said first and second plurality of longitudinally extending circumferentially spaced ball races of said inner joint member and said outer joint member, 20 respectively, said outer surface and said inner surface of said annular ball cage member being spherical surfaces that are ;concentric with one another; and 'a hub attached to said one end of said annular outer joint member, said hub having a centrally positioned cavity therein. S' 25 22. The constant velocity universal joint of claim 21 wherein said exterior spherical surface of said inner joint member and Alt said interior spherical surface of said annular outer joint member are concentric with each other. The constant velocity universal joint of claim 21 wherein said hub and said annular outer joint member are united by a snap ring. "24. The constant velocity universal joint of claim 21 further comprising a retaining rirng interposed said inner joint member and said drive means for mounting said inner joint member to said drive means. 23 The constant velocity universal joint of claim 21 wherein said driven shaft has a plurality of spline setsi on one end thereof, each spline set having splines circumferentially spaced apart and in axial alignment with said axis of said driven shaft.

26. A constant velocity universal joint 'tnilyas described with reference'to Fig. 1 and FJ 2 to Fig. 8 of the drawings. DATED this 16th day of August 1993 GKN-AUTOMOTIVE, INC. Patent Attorneys for the Applicant: F.B. RICE CO. 0 so