SLIDING BALL JOINT HAVING CROSSING RACEWAYS HAVING A DIFFERENT ANGLE OF INCLINATION AND A MINIMUM RADIAL DISTANCE

Abstract

A sliding ball joint comprising a joint outer part having inclined ball raceways which are formed on an inner periphery and which are arranged about an axis of rotation of the joint outer part, a joint inner part having inclined ball raceways, which are formed on an outer periphery and which are arranged about an axis of rotation of the joint inner part. Ball raceways of the joint outer part and of the joint inner part face each other in pairs and have angles of inclination opposite to each other, one ball per ball raceway pair, and a cage, which is arranged between the joint outer part and the joint inner part and having windows, in which the balls are accommodated. The joint outer part and the joint inner part each have at least two groups of inclined ball raceways, the groups being different with respect to the magnitude of the angle of inclination to the respective axis of rotation, wherein a first group of ball raceways include an angle of inclination (alpha) with the respective axis of rotation, and a second group of ball raceways include an angle of inclination (beta) with the respective axis of rotation, wherein < (alpha less than beta) applies to the magnitudes. The ball raceways of the first group have an identical first, minimum radial distance from the respective axis of rotation and the ball raceways of the second group have an identical second, minimum radial distance from the respective axis of rotation, and the first radial distance and second radial distance differ.

Claims

1. A sliding ball joint, comprising: a joint outer part having inclined ball raceways, which are formed on an inner periphery and which are arranged about an axis of rotation of the joint outer part, a joint inner part having inclined ball raceways, which are formed on an outer periphery and which are arranged about an axis of rotation of the joint inner part, wherein ball raceways of the joint outer part and of the joint inner part face each other in pairs and have angles of inclination opposite to each other, one ball per ball raceway pair, and a cage, which is arranged between the joint outer part and the joint inner part and having windows, in which the balls are accommodated, wherein the joint outer part and the joint inner part each have at least two groups of inclined ball raceways, the groups being different with respect to the magnitude of the angle of inclination to the respective axis of rotation, wherein a first group of ball raceways include an angle of inclination (alpha) with the respective axis of rotation, and a second group of ball raceways include an angle of inclination (beta) with the respective axis of rotation, wherein < (alpha less than beta) applies to the magnitudes and the ball raceways of the first group have an identical first, minimum radial distance from the respective axis of rotation and the ball raceways of the second group have an identical second, minimum radial distance from the respective axis of rotation and the first radial distance and second radial distance differ in magnitude.

2. The sliding ball joint according to claim 1, wherein furthermore for the magnitudes the following is true: 1>/>0.075, preferably the following is true: 1>/>0.1.

3. The sliding bail joint according to claim 1, wherein the first radial distance is greater than the second radial distance.

4. The sliding ball joint according to claim 1, wherein each of the ball raceways of the first and/or second group is arranged as being located about the respective axis of rotation in a tangential plane of a cylinder surface, and are preferably defined by a tangent to a cylinder surface about the respective axis of rotation.

5. The sliding ball joint according to claim 1, wherein the magnitude of the difference from the most minimum radial distance of the first group and the most minimum radial distance of the second group is between 0.01 mm and 10.00 mm.

6. The sliding ball joint according to claim 1, wherein the angle of inclination (Beta) is selected such that it at least corresponds to half an angle of flexion, about which the joint outer part is jointly pivotable in relation to the joint inner part.

7. The sliding ball joint according to claim 1, wherein at least the number of the ball raceways of the first group is equal to the number of the ball raceways of the second group.

8. The sliding ball joint according to claim 1, wherein, in circumferential direction, the algebraic sign of the angle of inclination changes from ball raceway to ball raceway.

9. The sliding ball joint according to claim 1, wherein the ball raceways at least of one group have a linear course.

10. The sliding ball joint according to claim 9, wherein the ball raceways of the second group, exclusively, have a linear course.

11. The sliding ball joint according to claim 1, wherein the ball raceways at least of one group have a curved course having a first order inflection point 1.

12. The sliding ball joint according to claim 11, wherein the curved course is point-symmetric to the first order inflection point 1.

13. The sliding ball joint according to claim 12, wherein the curved course is defined by a constant curvature radius section by section across at least a quarter, of its overall course.

14. The sliding ball joint according to claim 13, wherein the ratio of the angle of inclination (alpha) and the curvature radius is in a range between 0.0001 and 1.

15. The sliding ball joint according to claim 14, wherein the ball raceways have a cross section in the form of a parabola, perpendicular to their direction of course.

16. The sliding ball joint according to claim 1, wherein the number of the balls is three or more.

17. The sliding ball joint according to claim 5, wherein the magnitude of the difference from the most minimum radial distance of the first group and the most minimum radial distance of the second group is between 0.10 mm and 1.00 mm.

18. The sliding ball joint according to claim 13, wherein the curved course is defined by a constant curvature radius section by section across at least one third of its overall course.

19. The sliding ball joint according to claim 16, wherein the number of the balls is 6 or 8.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further features and advantages of the invention will become apparent from the following description of an exemplary embodiment of the invention which is intended to be non-limiting, which in the following will be explained in more details by making reference to the figures, wherein:

[0029] FIG. 1 schematically shows an overall view of a ball sliding join according to the invention,

[0030] FIG. 2 schematically shows a joint inner part of a ball sliding joint according to the invention,

[0031] FIG. 3 shows an elevational view and a projection of neighboring ball raceways of a first and second group having angles of inclination and of a joint inner part,

[0032] FIG. 4a shows a sectional view along a bail raceway of a first group having radial distance r.sub.,

[0033] FIG. 4b shows a sectional view along a ball raceway of a second group having radial distance r.sub.,

[0034] FIG. 5 shows an elevational view of a joint inner part of a ball sliding joint according to the invention, especially showing the difference of the ball raceways with respect to the radial distance.

[0035] FIG. 6 shows an elevational view of three consecutive ball raceways, wherein the ball raceways outwardly situated in this figure have a linear course and the ball raceway located between these two (central ball raceway) has a curved course.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0036] In the various figures equal parts with respect to their function are throughout referred to by the same reference numbers so that the latter generally will only be described once.

[0037] FIG. 1 shows an overall view of a ball sliding joint 1 according to the invention having inclined ball raceways 15. The sliding ball joint 1 comprises a joint outer part 10, a cage 30 containing balls, not shown herein, and a joint inner part 20, and it is arranged at an end of a pin 11.

[0038] The joint outer part 10 essentially is a circular hollow cylinder having an inner periphery 12, in the inner surface 13 thereof eight inclined ball raceways 15 are formed. The bail raceways 15 extend as grooves in the inner surface 13, along the longitudinal axis of the circular hollow cylinder, about an axis of rotation 25 of the joint outer part 10.

[0039] The joint inner part 20 is arranged within the joint outer part 10, and essentially is a circular hollow cylinder having an outer periphery 18, which defines an outer surface 19, in which eight inclined ball raceways 15 are formed. The ball raceways 15 extend as grooves in the outer surface 19, along the longitudinal axis of the circular hollow cylinder, about an axis of rotation 25 of the joint outer part 20. In the representation of the straight ball sliding joint 1 the axes of rotation 25 of the joint outer part 10 and the joint outer part 20 coincide.

[0040] The cage 30 is arranged between the joint outer part 10 and the joint inner part 20. The cage 30 is circularly formed, having eight windows, each one having arranged therein one ball.

[0041] The ball raceways 15 of the joint outer part 10 and the joint outer part 20 face each other in pairs, each one forming a ball raceway pair, into each one of which one ball is inserted.

[0042] The joint outer part 10 and the joint inner part 20 each comprise two groups of ball raceways 15 that are alternatingly arranged. A first group of ball raceways 15.sub. having an angle of inclination and a second group of ball raceways 15.sub. having an angle of inclination . The angles of inclination is the angle, with which a perpendicular projection of the ball raceway onto a plane, in which the axis of rotation is located (herein the drawing plane), intersects the axis of rotation.

[0043] For clarification of the arrangement of the ball raceways 15.sub., 15.sub., in FIG. 2 a joint inner part 20 of a ball sliding joint 1 according to the invention is shown once again. As described above, the joint inner part 20 comprises eight ball raceways 15, wherein four ball raceways 15.sub. of a first group and four ball raceways 15.sub. of a second group alternate, respectively. The ball raceways 15.sub., 15.sub. of the first and the second group differ from each other by their angle of inclination and , which they include with the axis of rotation 25. According to the invention, the following is true for the magnitudes of the angles of inclination: <, and 1>/>0.1.

[0044] For further illustration of advantageous embodiments of the invention, especially of features of the ball raceways 15 the FIGS. 4-5 show projections and sectional views across ball raceways 15 of a (schematic) joint inner part 20. All features of the described ball raceways 15 equivalently relate to the respective ball raceways 15 of a joint outer part 10, which form raceway pairs with the described ball raceways 15 of the joint outer part 20 ball (see above).

[0045] FIG. 3 shows an elevational view and a projection of neighboring ball raceways 15.sub. and 15.sub. of a joint inner part 20, respectively. The ball raceways 15.sub., 15.sub. are projected onto a cylinder surface 26 about the axis of rotation 25. Also shown are projections of the respective axis of rotation 25 onto the cylinder surface 26. The two ball raceways 15.sub., 15.sub. differ from each other with respect to the algebraic sign and the magnitude of the angle of inclination and with the projection of the respective axis of rotation 25. For clarification of the respective angles of inclination in FIG. 3 an axis y-y is drawn, extending along the ball raceways 15.sub. and including the angle of inclination with the axis of rotation 25. Similarly, an axis x-x is drawn, extending along the ball raceways 15.sub. and including the angle of inclination with the axis of rotation 25.

[0046] The FIGS. 4a and 4b each show sectional views along the axis y-y and along the axis x-x, respectively, to illustrate other possible embodiments of ball raceways 15.

[0047] FIG. 4a shows a sectional view along the axis y-y across a ball raceway 15.sub., as can be seen in FIG. 3. FIG. 4b shows a sectional view along the axis x-x across a ball raceway 15.sub., as can be seen in FIG. 3. The ball raceway 15.sub. belongs to a first group of ball raceways 15.sub.60 , all of which including a matching angle of inclination having the magnitude to the associated axis of rotation 25. The minimum radial distance of the ball raceways 15.sub. of the first group to the respective axis of rotation 25 is r.sub.. The ball raceway 15.sub. belongs to a second group of ball raceways 15.sub., all of which including a matching angle of inclination having the magnitude to the associated axis of rotation 25. The minimum radial distance of the ball raceways 15.sub. of the second group to the respective axis of rotation 25 is r.sub.. For the magnitudes of the angles of inclination the following is true: 1>/>0.075 and for the radial distances the following is true: r.sub.>r.sub..

[0048] FIG. 5 shows a cross section of a preferred embodiment of a joint inner part of the ball sliding joint according to the invention, in which the minimum, first radial distance r.sub. of the first group 15.sub. is greater than der minimum second radial distance r.sub. of the second group 15.sub.. Thus, the following is true: r.sub.>r.sub., wherein for the magnitudes of the angles of inclination the following is true: < and 1>/>0.075. The radial jump 36 shown in FIG. 5 of the minimum radial distance allows the joint volume to be more effectively utilized, moreover, due to the radial jump 36 a different introduction of the forces in the respective group 15.sub., and 15.sub., respectively, which may advantageously utilized in the designing the raceways. Consequently, ball raceways having lower angle of inclination become subjected to heavier loads. Due to the radial jump 36, with ball raceways of the group 15 it is possible to compensate the load caused by the lower bevel in that the radial distance of the associated ball raceways is increased, Thus, the sliding joint will globally become more resistant,

[0049] FIG. 6 shows a projection of three ball raceways, the two outer ball raceways comprising a straight course 48, the ball raceway located between the two outer ones (central ball raceway) having a curved, S-shaped course. The S-shaped course is characterized by a first order inflection point 45. The curved, S-shaped course 47 of the ball raceways is exclusively formed in the first group as having the angle of inclination , whereas the straight course is exclusively formed in the second group. The S-shaped course is characterized in that at least one third of the overall course is defined by a constant curvature radius 46, wherein the ratio between the first angle of inclination (alpha) and the curvature radius is in a range of between 0.0001 and 1. In FIG. 6 the curvature radius is schematically represented by an arrow, wherein the broken line part of the arrow is to indicate that the curvature radius is actually greater than shown.

LIST OF REFERENCE

[0050] 1 sliding ball joint [0051] 10 joint outer part [0052] 11 pin [0053] 12 inner periphery [0054] 13 inner surface [0055] 15 ball raceways [0056] 18 outer periphery [0057] 19 outer surface [0058] 20 joint inner part [0059] 25 axis of rotation [0060] 26 cylinder surface [0061] 30 cage [0062] 35 radial distance [0063] 36 radial jump [0064] 45 first order inflection point [0065] 46 curvature radius [0066] 47 all raceways having curved S-shaped course [0067] 48 ball raceways having straight course

[0068] Having described preferred embodiments of the invention, it will be apparent to those skilled in the art to which this invention relates, that modifications and amendments to various features and items can be effected and yet still come within the general concept of the invention. It is to be understood. that all such modifications and amendments are intended to be included within the scope of the present invention.