EP1299653A1

EP1299653A1 - Constant velocity ball joint with ball pairs whose tracks are located on symmetrical planes

Info

Publication number: EP1299653A1
Application number: EP01943447A
Authority: EP
Inventors: Peter Schwärzler
Original assignee: GKN Loebro GmbH
Current assignee: GKN Driveline Deutschland GmbH
Priority date: 2000-07-10
Filing date: 2001-05-25
Publication date: 2003-04-09
Also published as: WO2002008624A1; BR0112303B1; US7025683B2; AU2001266024A1; JP2004504570A; JP4969758B2; BR0112303A; DE10033491A1; US20040254021A1; DE10033491C2

Abstract

The invention relates to a constant velocity ball joint having the following characteristics: the cage windows receive ball pairs (38 1 m 38 2); when the ball joint is extended, the angular distance (al) of the balls in the central plane of the joint within individual ball pairs is smaller than the angular distance (a2) between balls pertaining to adjacent pairs; the center lines of the set of tracks of the ball pairs extend in planes (F2, G2) which are parallel to one another.

Description

Fixed ball constant-velocity joint with pairs of balls, the tracks of which lie in symmetrical planes

Besehreibung

The invention relates to a ball constant-velocity fixed joint with an outer joint part with a first longitudinal axis, which forms an interior with outer tracks running longitudinally therein, and with an inner joint part with a second longitudinal axis, which forms a hub body with inner tracks running longitudinally thereon, the outer tracks and the inner tracks form pairs of tracks , where a torque-transmitting ball is guided in each track set, the outer tracks and the inner tracks each have curved center lines, the center lines of the individual track sets intersecting in the joint center plane normal to the longitudinal axes when the joint is stretched, a ball cage holds the balls in circumferentially distributed cage windows and guides the balls when the joint is bent on the bisecting plane between the longitudinal axes.

Such joints can be so-called Rzeppa joints, in which the center lines of path sets are generally formed by arcs, the center points of which are offset relative to one another on the longitudinal axes with respect to the center plane of the joint. However, such joints can also be designed as UF joints, in which the center lines of the web sets are monotonically increasing or monotonically decreasing with respect to the longitudinal axes, whereby axially undercut-free webs are formed in each case. Joints of these types can also be designed as counter track joints, in which a part of the track sets opens in a first axial direction and another part of the track sets opens in the opposite axial direction opens. This means that the center lines of the outer tracks in the outer joint part as well as the center lines of the inner tracks in the inner joint part each form two groups with different curvature profiles in the longitudinal profile, based on the longitudinal axis.

Joints of this type are mounted by over-bending the joint, with an excessive bending angle between the longitudinal axes being set relative to the operating area, so that the cage windows emerge from the outer joint part and the balls can be inserted radially into the cage windows. To enable this type of assembly, the cage windows must be longer in the circumferential direction than would be necessary to bend the joint in the operating area. As a result, the width of the webs between the cage windows is reduced and the cage is weakened.

From DE 24 61 298 B1 and from DE 197 04 761 A1 it is already known to provide sliding joints with arrangements of ball tracks which enable pairs of balls to be received by the individual cage windows of the ball cage.

The present invention has for its object to provide a compact fixed joint in a given space with the highest possible torque capacity and good efficiency. This constant velocity fixed joint should in particular be economical to manufacture.

A first solution consists in a joint with the features: the cage windows each receive pairs of balls, when the joint is stretched, the angular distance αr1 between the center lines of the path sets or the balls within the individual pairs of balls is smaller than in the joint center plane the angular distance a2 between the center lines of track sets or the balls which belong to adjacent pairs, the center lines of the track sets of the pairs of balls run in mutually parallel planes.

A second solution consists of a joint with the features: the cage windows each receive pairs of balls; when the joint is stretched, the angular distance 1 between the center lines of the path sets or the balls within the individual pairs of balls is smaller than the angular distance in the joint center plane al between the center lines of path sets or balls that belong to adjacent pairs, the center lines of the path sets of the pairs of balls run in planes that intersect outside the joint in parallels to the longitudinal axes.

A third solution consists in a joint with the features: the cage windows each receive pairs of balls; when the joint is stretched, the angular distance α1 between the center lines of the path sets or the balls within the individual pairs of balls is smaller than the angular distance in the joint center plane al between the center lines of path sets or balls that belong to adjacent pairs, the center lines of the path sets of the pairs of balls each run symmetrically to a plane through the longitudinal axes and have the smallest distance from one another in the joint center plane.

With a preferred minimum number of four pairs of balls, compared to today's known six-ball and eight-ball joints, there is the possibility of increasing the torque capacity and improving the efficiency given the size of the joint.

A joint with these features has the essential advantage that the webs between the cage windows can be significantly widened due to the halved number of cage windows. This is particularly favored by the unequal angular distances 1, a1 that are provided between the center lines of the path sets of the pairs of balls on the one hand and the center lines of the path sets of balls of adjacent pairs on the other hand.

This unequal division angle of the webs over the circumference also has the purpose of suppressing vibrations to which joints with a uniform pitch angle of the webs tend to be suppressed. If the two different angular distances form a ratio of σ2 / 1 between 1.2 and 1.8, in particular of about 1.5, this leads to an effect of suppressing such vibrational excitations, since the excitation of the two balls lying closer together in a pair 180 ° out of phase with the excitation of two balls of adjacent pairs located further apart.

According to the field of the invention mentioned at the outset, these embodiments can be used for joints in which the center lines of the first tracks and the second tracks change their distance from the longitudinal axis of the corresponding component in the longitudinal course (Rzeppa, UF), or in which the Center lines of the first tracks and the second tracks of the track sets of the pairs of balls change their distance from the longitudinal axis of the respective component in opposite directions in the longitudinal course, ie form so-called counter track joints.

If one considers in detail the path sets of the pairs of balls, it follows for the first-mentioned joint type (Rzeppa, UF) that the center lines of the two outer paths (in the outer joint part) of each pair of paths run symmetrically to one another and the center lines of the two inner paths (in the inner joint part) of each pair of tracks symmetrically to run. In contrast, it is provided for the second type of joint (opposing track joint) that the center line of the outer track (in the outer joint part) of one set of tracks of a pair of tracks runs symmetrically to the center line of the inner track (in the inner joint part) of the other track set of the pair of tracks and the center line of the inner track ( in the inner joint part) of one set of tracks of this pair of tracks runs symmetrically to the center line of the outer track (in the outer joint part) of the other set of tracks of the pair of tracks.

By suitable distance variation of the center lines of the sets of pairs of balls, which differs from the equidistant design of the center lines, the purpose is that the hub webs on the inner part or the webs in the outer part between the sets of pairs of balls do not become too narrow towards their ends and the cage window length required for assembly is minimized in the circumferential direction.

Another advantageous embodiment of a joint of the type mentioned is that the cage windows have circumferentially extending ball contact guide flanks that are parallel to each other, and these ball contact guide flanks have connecting ball contact end edges that run essentially radially to the longitudinal axis of the ball cage. This makes it possible to give the balls the necessary freedom of movement within the cage window when the joint is extremely bent while gaining strength. The cage windows can in this case first be punched out in the circumferential direction shorter than is ultimately necessary, in which case external bevels are then worked out on the ball contact end edges of the cage windows.

Preferred exemplary embodiments of the invention are illustrated below with reference to the drawings. Show here

1 shows a joint according to the prior art a) in cross section through the joint center plane, b) in section C-C according to FIG. 1a;

2 shows a joint according to the invention in a first embodiment as a UF joint a) in cross section through the joint center plane, b) in section AA according to FIG. 2a, c) in section BB according to FIG. 2a, d) in an individual representation of the inner joint part, e) in an individual representation of the outer joint part;

3 shows a joint according to the invention in a second embodiment as a UFC joint a) in cross section through the joint center plane, b) in section AA according to FIG. 3a, c) in section BB according to FIG. 3a, d) in section CC according to FIG. 3a, e) in an individual representation of the inner joint part, f) in an individual representation of the outer joint part;

4 shows a joint according to the invention in a third embodiment with a modified cage window a) in cross section through the joint center plane, b) in section A-A according to FIG. 4a, c) in section B-B according to FIG. 4a.

In Figure 1, a constant velocity fixed joint 11 according to the prior art is shown as a six-ball joint on which an outer joint part 12 with outer ball tracks 13, an inner joint part 14 with inner ball tracks 15, a ball cage 16 with cage windows 17 and balls 18 contained therein can be seen. The cage windows 17 have parallel ball contact guide flanks 19, 20 running in the circumferential direction and ball contact end flanks 21, 22 connecting them. The respective pairs of flanks 19, 20; 21, 22 are parallel to each other. Corresponding outer ball tracks 13 and inner ball tracks 15 each form track sets in the sense of the use of this term in this application. The angular distance between the individual pairs of tracks is uniformly α _n . The balls 18 lie with their centers in the joint center plane E _T. The longitudinal axes are designated together with S-.

A pin 23 for introducing a torque is formed on the outer joint part 12. In the inner joint part 14 there is a longitudinal bore 24 for inserting a shaft end for transmitting the torque.

FIG. 2 shows a fixed constant-velocity ball joint 31 according to the invention with four pairs of balls, on which an outer joint part 32 with outer ball tracks 33, an inner joint part 34 with inner ball tracks 35, a ball cage 36 with four circumferentially distributed cage windows 37 and pairs of balls 38 can be seen. The cage windows 37 have parallel ball contact guide flanks 39, 40 running in the circumferential direction and ball contact end flanks 41, 42 connecting them. Radially opposed outer ball tracks 33 and inner ball tracks 35 each form track sets according to the use of this term in the present application.

In the central plane E _{2 of} the joint shown in a), the angular distance α1 between the path sets of a pair of balls 38... 38 _{2 is} smaller than the angular distance al between the path sets of balls of adjacent pairs of balls. On average through the joint center plane E ₂ , two pairs of planes F ₂ , G ₂ , H ₂ , I _{2 are} shown, in each of which the center points of the balls lie and which are parallel to one another in pairs. These levels and thus the center lines of path sets of pairs of balls are each pair-wise symmetrical to radial planes M ₂ , N ₂ through the longitudinal axes S ₂ , which are designated together. In section AA shown in b) the mutually parallel planes F ₂ , G _{2 are} also indicated. As is illustrated in the section BB shown in c), which is offset from the center, these planes each take up the center lines La ,, Li ₂ , La ₂ , Li ₂ of outer ball tracks and inner ball tracks that intersect at the center points of the balls. When viewed from the joint opening side, the path sets defined by these path center lines form undercut-free formations. The section of the plane G ₂ shown in c) is also characteristic for the planes F ₂ , H ₂ and I ₂ . The center line of the path sets of pairs of balls thus run in parallel planes and equidistant from one another in the same direction.

In d) four pairs of inner ball tracks 35, 35 ₂ can be seen on the inner joint part 34, between each of which there is a web 47, while between two inner ball tracks of adjacent pairs of tracks there is a web 48 of the second type of greater width. It can be seen that the four pairs of inner ball tracks 35, 35 ₂ are equal to each other and the inner ball tracks 35 ,, 35 ₂ of a pair are in mirror symmetry to each other. From the right side of the inner joint part facing the joint opening, all inner ball tracks 35 are free of undercuts.

In illustration e), outer spherical tracks 33,, 33 ₂ arranged in pairs on the outer joint part 32 can be seen, which are separated by a web 45 of smaller width, while a web 46 of the second type is visible between outer ball tracks 33 of adjacent pairs of ball tracks, which is of significantly greater width Has. It is clear that the four pairs of outer ball tracks 33, 33 ₂ are designed identically to one another and that the two outer ball tracks 33, 33 _{2 of} a pair of ball tracks run symmetrically to the web 45. All outer ball tracks 33 are undercut-free when viewed from the joint opening side. A pin 43 for introducing a torque is formed on the outer joint part 32. In the inner joint part 34 there is a longitudinal bore 44 for inserting a shaft end for transmitting the torque.

FIG. 3 shows a fixed constant-velocity ball joint 51 according to the invention with four pairs of balls, on which an outer joint part 52 with outer ball tracks 53, an inner joint part 54 with inner ball tracks 55, a ball cage 56 with four circumferentially distributed cage windows 57 and pairs of balls 58 can be seen. The cage windows 57 have parallel ball contact guide flanks 59, 60 running in the circumferential direction and ball contact end flanks 61, 62 connecting them. Radially opposing outer ball tracks 53 and inner ball tracks 55 each form track sets according to the use of this term in the present application.

In the central plane E _{3 of} the joint shown in a), the angular distance α between the sets of balls of a pair of balls is smaller than the angular distance a1 between the sets of balls of adjacent pairs of balls. On average through the joint center plane E ₂ , two pairs of planes F ₃ , G ₃ , H ₃ , I _{3 are} shown, in each of which the center points of the balls lie and which are parallel to one another in pairs. These planes and thus the center lines of path sets of pairs of balls are each pair-wise symmetrical to radial planes M ₃ , N ₃ through the longitudinal axes S ₃ , which are designated together. In section AA shown in b) the mutually parallel planes F ₃ , G _{3 are} also indicated. As is illustrated in the cuts BB, CC shown in the center in c) and d), these planes each take up the center lines La ,, La ₂ of outer ball tracks of a pair of balls, which align with correspondingly symmetrical center lines of inner ball tracks cut the center of the balls. Here form the path sets defined by these path center lines from the joint opening side, viewed in opposite directions, formations. The section of plane G ₃ shown in c) is also characteristic of plane I ₂ , the section of plane F ₃ shown in d) is also characteristic of plane H ₃ . However, the center line of the sets of pairs of balls thus run in opposite directions in parallel planes, with a symmetry between the center lines of one outer ball track and one inner ball track of the two track sets relative to one another.

In e) four pairs of inner ball tracks 55, 55 ₂ can be seen on the inner joint part 54, between each of which there is a web 67, while between two inner ball tracks of adjacent pairs of webs there is a web 68 of the second type of greater width. It can be seen that the four pairs of inner ball tracks 55, 55 ₂ are identical to one another and the inner ball tracks 55, 55 _{2 of} a pair are recessed in opposite directions to one another.

From the right side of the inner joint part facing the joint opening, only the ball tracks 55 _{2 are free of} undercuts, but viewed from the left side facing the floor, the ball tracks 55 are free of undercuts.

In the illustration f), outer ball tracks 53, 53 ₂ arranged in pairs on the outer joint part 52 can be seen, which are separated by a web 65 of smaller width, while a web 66 of a second type is visible between outer ball tracks 33 of adjacent pairs of ball tracks, which has a significantly greater width Has. It is clear that the four pairs of outer ball tracks 53, 53 ₂ are designed identically to one another and that in each case the two outer ball tracks 53, 53 _{2 of} a pair of tracks are recessed in opposite directions. The ball tracks 53 are viewed from the joint opening side without undercut, the ball tracks 53 ₂ are viewed from the joint bottom without undercut. A pin 63 for introducing a torque is formed on the outer joint part 52. In the inner joint part 54 there is a longitudinal bore 64 for inserting a shaft end for transmitting the torque.

FIG. 4 shows a fixed constant-velocity ball joint 31 according to the invention with four pairs of balls, which essentially corresponds to that shown in FIG. Deviating from this, however, the ball contact end flanks 41 ', 42' are designed radially to the longitudinal axes of the joint. For the rest, all details are the same. Reference is made to the description of FIG. 2.

Claims

claims

1. Fixed ball constant-velocity joint (31, 51, 71) with an outer joint part (32, 52, 72) with a first longitudinal axis, which forms an interior with outer tracks (33, 53, 73) running longitudinally therein, and with an inner joint part (34, 54, 74) with a second longitudinal axis, which forms a hub body with inner tracks (35, 55, 75) running longitudinally thereon, the outer tracks and the inner tracks form sets of tracks, a torque-transmitting ball (38, 58, 78) being guided in each track set, the outer tracks and the inner tracks each have curved center lines, the center lines of the individual track sets intersecting when the joint is stretched in the joint median plane (E ₂ , E ₃ , E ₄ ) normal to the longitudinal axes, a ball cage (36, 56, 76) takes the balls (38, 58, 78) in circumferentially distributed cage windows (37, 57, 77) and guides the balls when the joint is bent to the bisector plane between the longitudinal axes,

with the characteristics:

the cage windows (37, 57, 77) each receive pairs (38 ,, 38 ₂ ; ...) of balls, with the joint extended (31, 51, 71) is in the joint median plane (E ₂ , E ₃ , E ₄ ) the angular distance 1 of the balls within the individual pairs (38 ,, 38 ₂ ; ...) of balls less than the angular distance al between balls that belong to adjacent pairs, the center lines of the path sets of the pairs (38, 38 ₂ ; ...) of balls run in mutually parallel planes.

2. Fixed constant-velocity ball joint (31, 51, 71) with an outer joint part (32, 52, 72) with a first longitudinal axis, which forms an interior with outer tracks (33, 53, 73) running longitudinally therein, and with an inner joint part (34, 54, 74) with a second longitudinal axis, which forms a hub body with inner tracks (35, 55, 75) running longitudinally thereon, the outer tracks and the inner tracks form sets of tracks, a torque-transmitting ball (38, 58, 78) being guided in each track set the outer tracks and the inner tracks each have curved center lines, the center lines of the individual track sets intersecting when the joint is stretched in the joint central plane (E ₂ , E ₃ , E ₄ ) normal to the longitudinal axes, a ball cage (36, 56, 76 ) receives the balls (38, 58, 78) in circumferentially distributed cage windows (37, 57, 77) and guides the balls when the joint is bent to the bisecting plane between the longitudinal axes,

with the characteristics:

the cage windows (37, 57, 77) each receive pairs (38 ,, 38 ₂ ; ...) of balls, with the joint extended (31, 51, 71) is in the joint median plane (E ₂ , E ₃ , E ₄ ) the angular distance a of the balls within the individual pairs (38 ,, 38 ₂ ; ...) of balls is smaller than the angular distance al between balls that belong to adjacent pairs, the center lines of the path sets of the pairs (38 ,, 38 ₂ ; ...) of balls run in planes that intersect outside the joint in parallel to the longitudinal axes (S ₂ , S ₃ , S ₄ ).

Fixed constant-velocity ball joint (31, 51, 71) with an outer joint part (32, 52, 72) with a first longitudinal axis, which forms an interior with outer tracks (33, 53, 73) running longitudinally therein, and with an inner joint part (34, 54, 74) With a second longitudinal axis, which forms a hub body with inner tracks (35, 55, 75) running slowly thereon, the outer tracks and the inner tracks form sets of tracks, wherein a torque-transmitting ball (38, 58, 78) is guided in each track set, the outer tracks and the inner tracks each have curved center lines, the center lines of the individual track sets intersecting when the joint is stretched in the joint center plane (E ₂ , E ₃ , E ₄ ) lying normal to the longitudinal axes, a ball cage (36, 56, 76) takes the balls (38, 58, 78) in circumferentially distributed cage windows (37, 57, 77) and guides the balls when the joint is bent on the bisecting line between the longitudinal axes,

with the characteristics:

the cage windows (37, 57, 77) each receive pairs (38 ,, 38 ₂ ; ...) of balls, with the joint extended (31, 51, 71) is in the joint median plane (E ₂ , E ₃ , E ₄ ) the angular distance α1 of the balls within the individual pairs (38 ,, 38 ₂ ; ...) of balls is smaller than the angular distance al between balls that belong to adjacent pairs, the center lines of the path sets of the pairs (38 ,, 38 ₂ ; ...) of balls each run symmetrically to a plane (M ₂ , M ₃ , M ₄ ) through the longitudinal axes (S ₂ , S ₃ , S ₄ ) and have the smallest distance from each other in the joint center plane.

4. Joint according to one of claims 1 to 3,

characterized,

that the center lines of the outer tracks (33) and the inner tracks (35) each change their distance from the longitudinal axis of the corresponding component in the longitudinal course. (UF, Rzeppa)

5. Joint according to one of claims 1 to 3,

characterized,

that the center lines of the outer tracks (53, 73) and the inner tracks (55, 75) of the sets of pairs of balls change their distance from the longitudinal axis of the respective component in the longitudinal direction in opposite directions. (Rzeppa)

6. Joint according to one of claims 1 to 5,

characterized,

that the ratio of the angular distances a1 to α1 is between 1.2 and 1.8 and is in particular 1.5.

7. Joint according to one of claims 1 to 6,

characterized,

that the cage windows (37 ') have circumferential ball contact guide flanks (39', 40 ') which are parallel to each other and ball contact end flanks connecting the ball contact guide flanks (41', 42 ') which are substantially radial to the longitudinal axis of the ball cage (36' ) run.

8. Joint according to one of claims 1 to 7,

characterized,

that the joint has four pairs (38 ,, 38 ₂ ; ...) of balls.

9. joint according to claim 4,

characterized,

that the center lines of the two outer webs (33, 73) of each pair of webs run symmetrically to one another and the center lines of the two inner webs (35, 75) of each web pair run symmetrically to one another.

10. Joint according to claim 5,

characterized,

that in each case the center line of the outer web (53,) of the one set of a pair of webs symmetrical to the center line

(55 ₂ ) of the inner path of the other path set of the path pair runs and the center line of the inner path (55,) of one path set of this path pair runs symmetrically to the center line

(53 ₂ ) the outer track of the other track set of the train pair runs.