NZ196333A - Constant velocity universal joint:tripod type,wear faces - Google Patents

Description

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CompJei© Specification Filedr^f'.^.'f/ Class: P'.fcf.ljjofc . J PuUlJL Data: 2.7. A^R 1984 O. Jc-irr-v'. Ho: l?f.7 Patents Form No. 5 PATENTS ACT 1953 COMPLETE SPECIFICATION Title:- "SLIDABLE TYPE CONSTANT VELOCITY UNIVERSAL JOINT" I/We, HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, of No. 27-8, 6 chome, Jingumae, Shibuya-ku, Tokyo, Japan, hereby declare the invention, for which we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly (described in and by the following statement (followed by page 1A) 196 SLIDEABLE TYPE CONSTANT VELOCITY UNIVERSAL JOINT FIELD OF THE INVENTION This invention relates to a constant velocity universal joint of the type including an outer rotatable member having axially extending grooves internally thereof, and an inner rotatable member having radially extending trunions which support rollers for axial sliding movement relatively to the trunions and for universal pivoting movement relatively thereto. The rollers are received within the said axially extending grooves of the outer member and roll axially thereof during orbital movement of the rollers upon rotation of the inner and outer members with the axes of the respective members inclined relatively to each other.

While not limited thereto, the invention of the present application finds particular application in a "tripod" type of constant velocity universal joint employed in the drive to front wheels of a motor vehicle.

PRIOR ART Typical examples of such "tripod" type constant velocity universal joints are disclosed in U.S. Patent Specification No. 4,192,154, and New Zealand Patent Specification No. 190102.

BACKGROUND OF THE INVENTION When employed in a front wheel drive for a motor vehicle,( * the axis of the respective inner and outer rotable members 1 of the universal joint are oriented in inclined relationship relatively to each other, both in dependence on the position and vertical movement of the vehicle wheels relatively to the vehicle body and in dependence on steering movement of the vehicle wheels relatively to the longitudinal axis of -1A- (p- the vehicle body. Conventionally, the outer rotatable member of the universal joint is affixed to the wheel hub with its axis of rotation lying in a substantially horizontal plane, and the axis of the inner rotable member is inclined 5 relatively to that plane.

Due to the inclination of the axis of the inner rotable member relatively to the axis of the outer rotatable member, the rollers carried by the trunions of the inner rotatable member are caused to move on an orbital path upon rotation 10 of the respective members, this requiring that the respective rollers move axially of the longitudinal grooves in the outer rotatable member to opposite sides of a median plane perpendicular to the axis of the outer rotatable member. Additionally, upon such movement of the rollers in-one axial 15 direction longitudinally of the grooves, the rollers must progressively slide axially of the trunions in one direction, and, upon movement of the rollers axially of the grooves in an opposite direction, the rollers must progressively slide axially of the trunions in a direction opposite to the first 2 0 direction, the axial sliding movement of the rollers relatively to the trunions occuring in addition to pivotal movement of the rollers relatively to the axis of the respective trunions, such as occurs as a result of the rollers moving along linear paths which are inclined relatively to the plane of 25 movement of the axis of the respective trunions.

At the time the rollers are moving axially outwardly along the trunions, the frictional restraint on such movement results in a force being exerted on the rollers in a direction radially inwardly of the axis of the outer rotatable member, 30 and conversely, upon movement of the rollers axially inwardly along the trunions, the frictional restraint imposed on such movement results in a force being exerted on the.rollers in a direction radially outwardly of the axis of the outer rotatable member. 2 1 96 3 3 3 Of necessity, and in'order to eliminate simultaneous contact of the rollers with both of the opposed axial side walls of the longitudinal grooves in the outer rotatable member, the rollers intentionally are formed for them to be 5 slightly undersized relatively to the width of the longitudinal grooves, such that, under normal operating conditions, simultaneous contact of the roller with both side walls of the grooves cannot occur.

Such simultaneous contact must be avoided, in that 10 axial movement of the respective rollers in one direction of rotation of the universal joint results in a rolling movement of the roller relatively to one side wall of the .groove, and * a rotary movement of the roller relatively to the opposite side wall of the groove in a direction which is opposite to 15 that required for rolling motion of the roller relatively to said opposite side wall.

For practical reasons, the opposite side walls of the longitudinal grooves are formed for them to be oppositely arcuately 2 0 concave and, the rollers are form finished on their outer periphery for them to be correspondingly convex, such that the rollers engage the associated side wall substantially in line engagement therewith.

While such an orientation of structure operates entirely 25 successfully in the absence of forces exerted on the rollers in a direction radially inwardly or radially outwardly of the axis of the outer rotatable member, such as occurs only when the axes of the inner and outer rotable members are aligned, in the presence of such radially inward or radially 30 outward forces, there is a tendency for the rollers to climb up the associated side wall with a consequence that the diametrically opposite side of the roller will come into engagement with the opposite side wall. 3 ^ The ability of the rollers to climb the associated side wall of the groove arises from the rollers being of a diameter slightly less than the width of the associated longitudinal groove and the lack of restraint on the rollers against movement radially of the axis of the outer rotatable member.

Such a condition is entirely disadvantageous, in that simultaneous contact of the rollers with both of the groove side walls results in the roller being restrained against free rotation, accompanied by a consequential increase in the internal friction within the universal joint, the production of heat and noise within the universal joint, and abrasion or scuffing of the groove side walls and of the periphery of the rollers.

OBJECT OF THE INVENTION It is the object of this invention to eliminate the possibility of the rollers coming into simultaneous engagement with the opposed groove side walls at those times when the rollers are subjected to a force acting radially inwardly of the axis of the outer rotable member.

INVENTIVE CONCEPT According to the present invention, each roller is provided with an abutment member at the side thereof closest to the axis of the outer rotable member, and the radially innermost portion of each groove side wall is provided with an abutment surface which is contacted by the abutment member prior to the roller reaching a position in which simultaneous engagement with both side walls of the groove would occur, engagement of the abutment member with the respective abutment surfaces acting firstly to prevent continued inward movement of the roller in a direction radially inwardly of the axis of the outer rotatable member, 4 196333 and secondly acting to overcome the frictional restraint imposed on the roller against free and unrestricted movement of the roller axially outwardly of its associated trunion.

DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the accompanying drawings, in which Figures 1 through 4 illustrate a known embodiment of "tripod" type constant velocity universal joint of the type disclosed in New Zealand Specification No. 190102 and in which Figures 5 through 8 illustrate preferred embodiments of the present invention, the respective figures of the drawings being as follows: Fig. 1 is a longitudinal partial cross-section through a constant velocity "tripod" type universal joint of known type; Fig. 2 is a cross-section taken on the line II-II of Fig. 1; Fig. 3 is an illustration of the universal joint shown in Fig. 1 in which an inner rotatable member thereof has been displaced for its longitudinal axis of rotation to be inclined relatively to the longitudinal axis of rotation of an outer rotatable member thereof; Fig. 4 is an enlarged framentary cross-sectional view illustrating a roller of the universal joint of Figs. 1 through 3 when in simultaneous contact with the opposed side walls of longitudinal grooves formed in the outer rotatable member; 196333 Fig. 5 is an illustration of a constant velocity "tripod" type universal joint incorporating a preferred embodiment of the present invention; Fig. 6 is a fragmentary cross-sectional view taken on the line VI-VI of Fig. 5; rO CO a> m CN i Fig. 7 is a fragmentary cross-sectional view of an alternative preferred embodiment of the present invention; and Fig. 8 is a fragmentary cross-sectional view of another preferred embodiment of the present invention.

DESCRIPTION OF THE PRIOR DISCLOSED EMBODIMENT Referring now to Figs. 1 to 4 of the drawings, there is illustrated a universal joint having an outer rotatable member a which includes grooves b extending longitudinally of the inner surface thereof, the respective side walls of the grooves being arcuately concave about a common longitudinal axis for them to be of complementary part-cylindrical form.

An inner rotatable member c extends into the outer rotatable member a and is freely movable within the outer rotatable member for the longitudinal axes of the respective inner and outer members to be inclined relatively to each other,, as is illustrated in Fig. 3. The inner rotatable member c terminates in radially extending trunions d which extend into the respective longitudinal grooves b, the respective trunions each carrying a roller assembly comprised by a roller e which is mounted for rotation on the trunion by inner and outer guide members f and g and a needle bearing h which is interposed between the roller e and the outer guide member g. The inner guide member f is slidable axially of the trunion d, the outer surface of the inner guide member f being spherical and received within a spherical seating within the outer guide member g, such that the roller e is supported for 6 1 9633 universal pivoting movement relatively to the trunion d.

With the axes of the respective inner and outer members aligned as illustrated in Figs. 1 and 2, torque applied to the inner rotatable member will produce a rotary movement of the outer rotatable member in the absence of rolling motion of the respective rollers e longitudinally of the groove walls b, and, in the absence of any movement of the respective roller assemblies axially of their supporting trunions.

Upon the axes of the respective inner and outer rotatable members becoming inclined relatively to each other, as is illustrated in Fig. 3, rotation of the inner rotatable member will result in movement of the rollers on an orbital path to opposite sides of a median plane which is perpendicular to the longitudinal axis of the outer rotatable member. When moving away from said median plane, the rollers, which are constrained to move axially of.the longitudinal grooves in the outer rotatable member, must pivot relatively to their associated trunion, and additionally, must move axially outwardly of the associated trunion. Conversely, when moving towards said median plane, the rollers must pivot relatively to their associated trunion in an opposite direction, and, must move axially inwardly of the associated trunion.

Owing to the frictional restraint imposed on such movement of the rollers relatively to the associated trunions, and which arises at the interface of the trunion d and the inner guide member f, and also at the interface of the inner guide member f and the outer guide member g, a force acting radially inwardly of the axis of the outer rotatable member is exerted on the rollers as they move away from said median plane, and, a force acting radially outwardly of the axis of the rotatable member is exerted on the rollers as they move towards said median plane.

In the event that the rollers were constrained against radial movement relatively to the axis of the outer rotatable member, the aforementioned radially inward and radially outward 12 DEC 1983 7 received 196333 forces exerted on the rollers would be of little consequence, in that those forces would be absorbed and dissipated at the interface of the rollers and the side walls of the respective longitudinal grooves. However, the geometry of the universal joint demands that the roller be "undersized" relatively to the width of the associated groove, such that it shall not simultaneously engage both of the respective side walls of the grooves. It is here noted that at the time the universal joint is rotating in one direction, the rollers are engaged with and rolling along one of the side walls of the grooves, and, at their opposite side are rotating oppositely to the direction of movement of the rollers along the respective grooves. It is for this reason that the rollers must be "undersized" in order to ensure that they do not simultaneously engage both of the opposite side walls of the grooves.

As a consequence of the rollers being "undersized" relatively to the width of the associated grooves, the rollers are not positively restrained against radial movement relatively to the axis of the outer rotatable member, but in fact are capable of such radial movement within a range determined by the extent to which the roller is "undersized" relatively to the width of the groove. In operation of the universal joint, the rollers move radially of the axis of the outer rotatable member under the influence of the radially inward and radially outward forces exerted thereon, with a consequential probability of the rollers simultaneously engaging both of the opposite side walls of the grooves.

Fig. 4 illustrates the consequence of radially inward movement of the rollers under the influence of a radially inward force exerted thereon. In Fig. 4, the roller is shown as having climbed the side wall of the groove to a position in which the lower edge of the roller is in simultaneous contact with both side walls of the groove. Such a condition is entirely disadvantageous, in that tVDECm? 1 Q A O Q O rotary movement of the roller is then restrained or possibly prohibited, and the roller must slide on the respective side walls of the groove, this resulting in an increase in internal friction within the universal joint, the production of heat and noise, and, the abrasion or scuffing of the groove side walls and of the roller periphery. An identical condition can arise in the event that a radially outward force is exerted on the rollers relatively to the axis of the outer rotatable member, under which condition the rollers move or climb upwardly in Fig. 4 to a position in which the upper edge of the roller is in simultaneous contact with both of the opposed side walls of the groove.

DESCRIPTION OF THE INVENTION / Referring now to Figs. 5 and 6, which show one embodiment of the present invention, there is illustrated a constant velocity universal joint having an outer rotatable member 1 incorporating internal axially extending grooves 2. An inner rotatable member 3 incorporates radially extending trunions 4 which respectively support rollers 5 for universal pivoting movement and for axial sliding movement relatively thereto by means of inner and outer guide members 6 and 7.

As previously described, the inner guide member 6 is slidable axially on the trunion 4 and has a spherical outer surface which is received within a spherical seating in the outer guide member 7, the roller 5 being supported on the outer guide member 7 by a needle bearing 8 for free rotational movement relatively to the outer guide member 7.

Also carried by the outer guide member 7 and rotatable relatively thereto is an abutment member 9, the abutment member 9 being supported on an axial extension 7a of the outer guide member 7 and being restrained against movement axially of the outer guide member 7 by means of an annular flange 7b of the outer guide member 7 and by its engagement at 9a with the adjacent face of the roller 5. Conveniently, the abutment member 9 also jVi.Z. PATENT OFFICE 19DECI983 196333 provides an end abutment for the needle rollers 8.

The inner periphery of the abutment member 9 is formed of a diameter slightly larger than the outer diameter of the outer guide member 7 and its flange 7b, such that the abutment member 9 is free to float relatively to the outer guide member 7 in a direction perpendicular to the longitudinal axis thereof. The outer periphery of the abutment member 9 is conical in form and is of an included angle complementary to the included angle between abutment surfaces 10, 10 formed at the radially inner most 10 edges of the side walls 2a, 2a. The diameter of the outer periphery of the abutment member 9 is chosen such that, when a force is applied to. the roller 5 in a direction acting radially inwardly of the axis of the outer rotatable member 1, the abutment member 9 will engage the abutment surfaces 10, 10 prior to the 15 roller reaching a position in which it is in siraultan'eous contact with both side walls 2a, 2a of the groove, and such that the abutment member will prohibit further movement of the roller in a direction radially inwardly of the axis of the outer rotatable member 1. Thus, the abutment member 9 inhibits the roller 5 2 0 reaching a position in which it can simultaneously engage both of the side walls 2a, 2a of the groove.

In operation, and at those times when the roller is in its correct position relatively to the groove, the abutment member is free to rotate at random and imposes little or no 25 frictional restraint on rotation of the roller 5 relatively t the outer guide member 7. In the event that the roller is subjected to forces which cause it to climb down that one of the groove side walls in which it is in rolling contact by the roller moving radially inwardly of the axis of the outer rotatable member 30 1, prior to the roller simultaneously engaging both side walls of the groove at the lower edge of the roller, the outer periphery 9b of the abutment member 9 engages the abutment surfaces 10, 10 to prevent further radially inward movement of the roller 5.

At this time, due to the' conicity of the abutment member 9 35 and the sliding contact of the outer periphery thereof with the abutment surfaces 10, 10, which act as earning surfaces, a force is exerted on the abutment member in a direction radially outwardly 1 Q Q Q o ifuyyo of the axis of the outer rotatable member 1, that force being transmitted directly to the roller 5 in opposition to the force exerted on the roller 5 in a direction radially inwardly of the outer rotatable member 1, and acting to assist in movement of the roller assembly in a direction radially outwardly along the trunion 4 for the roller again to assume proper seating., engagement with that one of the side walls in which it is in rolling contact.

In the event that the direction of rotation of the universal joint is reversed from the direction illustrated in Fig. 6, the free-floating relationship of the abutment member 9 relatively to the outer guide member 7 accommodates the required relative angular movement between the inner and outer rotatable members 1 and 3 which is required to bring the roller 5 into spaced relationship with the previously engaged side wall 2a and into rolling engagement with the opposite side wall 2a.

In order to control the movement of the roller in a direction radially outwardly of the axis of the outer rotatable member 1 and thus prevent simultaneous engagement of the roller with both side walls 2a, 2a of the groove, preferably the outer guide member 7 is dimensioned for it to engage the bottom wall of the groove 2 prior to the roller reaching a position in which simultaneous engagement with both side walls of the groove can occur. Alternatively, an additional abutment member 9 (not shown) can be provided at the opposite axial end of the roller, in which event cooperating abutment surfaces 10, 10 would be provided adjacent the bottom wall of the groove in a manner which will be easily understood.

Referring now to Fig..7, in which the same reference numerals have been used to identify corresponding elements to those illustrated in Fig. 6, the abutment member is formed integrally with the outer guide member 7 as a radial flange 9 on an axial extension 7a of the outer guide member 7. In Fig. 7, as in Fig. 6, a conical peripheral surface 9b of the abutment member 9 is dimensioned such that, without regard to the direction of drive N.Z. PATENT OFFICE 1 9 DEC 1983 196333 of the universal joint, the conical peripheral surface 9b will engage the abutment surfaces 10, 10 prior to a condition arising in Which the roller 5 can simultaneously contact both of the opposed side walls 2a, 2a of the groove 2.

In Fig. 7, axial play slightly in excess of normal manufacturing tolerances is provided between the roller 5 and the outer guide member 7, in order that any force applied to the outer guide member in a direction radially inwardly of the axis of the outer rotatable member 1 will result in the outer guide 10 member moving radially inwardly to an extent sufficient to produce engagement of the conical surface 9b with the abutment surfaces 10, 10 prior to a radially inward force being exerted on the roller 5. Upon engagement of the conical surface with the abutment surfaces 10, 10, the inner and outer guide members 15 6 and 7 are forced axially outwardly along the trunion 4 in the substantial absence of any radially inward force being exerted on the roller 5 relatively to the axis of the outer rotatable member 1.

Referring now to Fig. 8, in which corresponding reference 2 0 numerals have been used to identify corresponding elements with those illustrated in Fig. 6, an annular abutment member 9 is positioned on a radial flange 7b formed on an extension 7a of the outer guide member 7, the abutment member having an upper planar surface 9a which provides an end seating for the roller 25 5, and having a lower planar surface 9c which abuts co-planar abutment surfaces 10, 10 formed at the radially inner most edges of the side walls 2a, 2a of the groove 2.

In a manner somewhat similar to that described with respect to Fig. 6, upon an axial force being exerted on the roller 5 3 0 in a direction radially inwardly of the anis of the outer rotatable member 1, the roller forces the abutment member into engagement with the abutment surfaces 10, and is then prevented from further radially inward movement by its engagement with the abutment member 9. The abutment member 9 is supported on the outer guide 35 member 7 in floating relationship therewith, and is of an axial ft N.Z. PATENT OFFICE 19DEC198J 12 length such that it engages the abutment surfaces 10, 10 and precludes further radially inward movement of the roller 5 prior to the roller 5 reaching a position by climbing down the side wall 2a, in which it would come.into contact simultaneously with both of the opposed side walls 2a, 2a of the groove 2.

While preferred embodiments of the invention have been described, it will be appreciated that various modifications may be made in the structures disclosed without departing from the scope of the invention as defined in the appended claims. 13 * >oo o WHAT WE CLAIM IS: - 1. A constant velocity universal joint of the type including an inner rotatable member, trunions extending radially of said inner rotatable member, roller assemblies supported on said trunions for sliding movement axially thereof, each roller assembly including a roller and members supporting said roller for universal pivoting movement relatively to the supporting trunion, an outer rotatable member having internal axially extending grooves, said grooves having opposite concave side walls in which said 10 rollers are received and held captive, said rollers being of a peripheral form complementary to that of said concave side walls and being of a diameter slightly less than the maximum width of said grooves for said rollers to be rollable longitudinally of one of said side walls with clearance from the 15 opposite side wall; and comprising an annular abutment member carried by each roller assembly, and an abutment surface extending longitudinally of 'each side wall and which is 2 0 engaged by the abutment member of the associated roller upon the movement of said roller in a direction radially of the longitudinal axis of said outer rotatable member. 2. The constant velocity universal joint according to

Claims (3)

1. Claim 1, in which said abutment member is an annular member and said roller assembly includes surfaces supporting said annular member for limited movement in a plane perpendicular to the longitudinal axis of the roller. N.Z. PATENT OFFICE f 9DEC1983 F-: >:ci:4 ? 3. The constant velocity universal joint according to Claim 2, in which said annular member is supported on a radial flange of said roller assembly, and provides an end abutment for needle rollers and for said roller of the assembly. c 4. The constant velocity universal joint according to
2. Claim 2, in which said annular member has a frusto conical outer periphery and said abutment surfaces are inclined at an included angle complementary to the included angle of said outer periphery. 5. The constant velocity universal joint according to Claim 4, in which said abutment surfaces are located at the edges of said side walls closest to the axis of said outer rotatable member. 6. The constant velocity universal joint according to Claim 1, in which said abutment member is an annular flange formed integrally with one of said members which support said roller for universal pivoting movement relatively to said trunion. 7. The constant velocity universal joint according to Claim 6, in which said annular flange provides an end abutment for needle rollers and said roller of the assembly. 8. The constant velocity universal joint according to Claim 6, in which said annular flange has a frusto conical outer periphery and said abutment surfaces are inclined at an included angle complementary to the included angle of said outer periphery. 9. The constant velocity universal joint according to Claim 6, in which said abutment surfaces are located at the 15 196333 edges of said side walls closest to the axis of said outer rotatable member.
3. Claim 3, in which said annular member has planar parallel radial surfaces, one of which provides an end abutment for needle rollers and said roller of the assembly, and the other of which extends substantially parallel to co-planar abutment surfaces located at the edges of said side walls. 11. A constant velocity universal joint substantially as herein described with reference to any one of the embodiments shown in Figures 5,6, 7 and 8 of the accompanying drawings. 10. The constant velocity universal joint according to 16