ANGULAR BALL BEARING ARRANGEMENT

Abstract

An angular contact ball bearing arrangement has first and second raceway elements having raceways and a plurality of balls therebetween. When viewed in cross section through one of the balls the arrangement is divided into first, second, third and fourth quadrants by an axis of rotation of one of the balls and a perpendicular axis perpendicular to the axis of rotation of the ball. Each ball has two contact points on each raceway that are offset from the perpendicular axis by #10 degrees, and the contacts points are each located in a different quadrant. Also the centre point of the radius curvature of the first raceway on one side of the perpendicular axis and the centre point of the radius of curvature of the first raceway on the other side of the perpendicular axis are in located in different quadrants.

Claims

1. An angular contact ball bearing arrangement having comprising: a first raceway element having a first raceway, a second raceway element having a second raceway, and a plurality of balls between the first raceway element and the second raceway element in contact with the first and second raceways, wherein, when viewed in cross section through one ball of the plurality of balls the angular contact ball bearing arrangement is divided into a first quadrant, a second quadrant, a third quadrant and a fourth quadrant arranged clockwise by an axis of rotation of the one ball and an axis perpendicular to the axis of rotation of the one ball, wherein the one ball contacts the second raceway at a first contact point in the first quadrant and a second contact point in the second quadrant and contacts the first raceway at a third contact point in the third quadrant and a fourth contact point in the fourth quadrant, wherein the second raceway lies in the first quadrant and in the second quadrant and the first raceway lies in the third quadrant and in the fourth quadrant, wherein a centre point of a radius of curvature of a portion of the second raceway in the first quadrant lies in the third quadrant, wherein a centre point of a radius of curvature of a portion of the second raceway in the second quadrant lies in the fourth quadrant, wherein a centre point of a radius of curvature of a portion of the first raceway in the third quadrant lies in the first quadrant, wherein a centre point of a radius of curvature of a portion of the first raceway in the fourth quadrant lies in the second quadrant, wherein the first contact point and the second contact point are offset from the axis perpendicular to the axis of rotation of the one ball and lie on the second raceway within an angle of ?10? from the axis perpendicular to the axis of rotation of the one ball, and wherein the third contact point and the fourth contact point are offset from the axis perpendicular to the axis of rotation of the one ball and lie on the first raceway within an angle of ?10? from the axis perpendicular to the axis of rotation of the one ball.

2. The angular contact ball bearing arrangement according to claim 1, wherein the radius of curvature of the portion of the second raceway in the first quadrant and the radius of curvature of the portion of the second raceway in the second quadrant intersect on the axis perpendicular to the axis of rotation of the one ball, and wherein the radius of curvature of the portion of the first raceway in the third quadrant and the radius of curvature of the portion of the first raceway in the fourth quadrant intersect on the axis perpendicular to the axis of rotation of the one ball.

3. The angular contact ball bearing arrangement according to claim 2, wherein the radius of curvature of the portion of the second raceway in the first quadrant and the radius of curvature of the portion of the second raceway in the second quadrant and the radius of curvature of the portion of the first raceway in the third quadrant and the radius of curvature of the portion of the first raceway in the fourth quadrant are identical.

4-5. (canceled)

6. The angular contact ball bearing arrangement according claim 1, wherein the radius of curvature of the portion of the second raceway in the first quadrant and the radius of curvature of the portion of the second raceway in the second quadrant and the radius of curvature of the portion of the first raceway in the third quadrant and the radius of curvature of the portion of the first raceway in the fourth quadrant are non-constant.

7. The angular contact ball bearing arrangement according to claim 1, wherein the angular contact ball bearing arrangement is a double-row angular contact ball bearing arrangement and wherein the plurality of balls include a first row of the plurality of balls and a second row of the plurality of balls.

8. The angular contact ball bearing arrangement according to claim 7, wherein the first raceway element or the second raceway element is configured as a divided raceway element, and wherein the second raceway element or the first raceway element is configured as a common raceway element.

9. The angular contact ball bearing arrangement according to claim 8, including a preloading mechanism for controlling the first, second, third and fourth contact points.

10. The angular contact ball bearing arrangement according to claim 1, wherein the angular contact ball bearing arrangement is a linear bearing, wherein the first raceway element is a rail and wherein the second raceway element is a carriage.

11. The angular contact ball bearing according to claim 1, wherein the first contact point is located in the first quadrant and the second contact point is located in the second quadrant and the third contact point is located in the third quadrant and the fourth contact point is located in the fourth quadrant.

Description

[0027] In the drawings:

[0028] FIG. 1: shows a schematic cross-sectional view of an angular contact ball bearing arrangement;

[0029] FIGS. 2-4: show schematic cross-sectional views of the angular contact ball bearing arrangement of FIG. 1 with differently arranged contact points;

[0030] FIG. 5: shows a schematic cross-sectional view of the angular contact ball bearing arrangement of FIG. 1 as a double-row angular contact ball bearing arrangement in an O-arrangement;

[0031] FIG. 6: shows a schematic cross-sectional view of the angular contact ball bearing arrangement of FIG. 1 as a double-row angular contact ball bearing arrangement in an X-arrangement; and

[0032] FIG. 7: shows a schematic cross-sectional view of the angular contact ball bearing arrangement of FIG. 1 as a linear bearing with a divided raceway element.

[0033] In the following, identical or functionally equivalent elements are identified by the same reference signs.

[0034] FIG. 1 shows an angular contact ball bearing arrangement 1 having a first raceway element 2 and a second raceway element 4. Balls 6 in the form of rolling elements are arranged between the raceway elements 2, 4. The balls 6 roll along raceways 8, which are arranged on the raceway elements 2, 4.

[0035] The angular contact ball bearing arrangement 1 can be designed as a rotary bearing or as a linear bearing. In the case of a rotary bearing, the first raceway element 2 and the second raceway element 4 correspond to the inner ring and the outer ring. In the case of a linear bearing, the first raceway element 2 and the second raceway element 4 correspond to the rail and the carriage.

[0036] In the case of the angular contact ball bearing arrangement 1 shown in FIG. 1, the raceways 8 can be theoretically divided into four quadrants I, II, III, IV. The division into the four quadrants I, II, III, IV is effected by the axis of rotation A.sub.R of the ball and an axis A.sub.S perpendicular to the axis of rotation A.sub.R. The raceway of the second raceway element 4 is formed by two segments 8-I, 8-II and lies in the first and second quadrants I, II and the raceway of the first raceway element 2 is formed by two raceway segments 8-III and 8-IV and lies in the third and fourth quadrants III, IV. As can be seen, the four quadrants I, II, III, IV and the axis of rotation A.sub.R of the ball are arranged obliquely with respect to the raceway elements 2, 4 and to the bearing axis of rotation A.sub.L.

[0037] The ball 6 comes into contact with the raceways 8-I, 8-II at two contact points P-I, P-II located in two contact zones 10-I and 10-II, and with the raceways 8-III and 8-IV at two contact points P-III, P-IV located in the contact zones 10-III and 10-IV. To ensure that the ball 6 contacts the raceways 8 at the contact points P-I, P-II, P-III, P-IV, the raceways 8 have a special configuration: The centre point M-I of the radius of curvature R-I of the raceway segment 8-I lies in the third quadrant III, the centre point M-II of the radius of curvature R-II of the raceway segment 8-II lies in the fourth quadrant IV, the centre point M-III of the radius of curvature R-III of the raceway segment 8-III lies in the first quadrant I and the centre point M-IV of the radius of curvature R-IV of the raceway segment 8-IV lies in the second quadrant II.

[0038] In the embodiment shown in FIG. 1, the intersection of the radii of curvature R-I, R-II of the first and the second quadrant I, II lies on the axis A.sub.S and the intersection of the radii of curvature R-III, R-IV of the third and the fourth quadrant III, IV also lies on the axis A.sub.S. However, the intersection may also not lie on the axis A.sub.S. The radius of curvature R here means the radius defining the curvature, i.e. the distance between the raceway 8 and the centre point M. In particular, as shown in FIG. 1, the straight line through M-I and M-III intersects the straight line through M-II and M-IV at the intersection S. In the case shown here, the intersection S simultaneously lies on the intersection of the axis of rotation A.sub.R and the axis A.sub.S, but this is not absolutely necessary. This specific configuration of the radii of curvature R of the raceways 8 ensures that the ball 6 contacts the raceways 8 at the contact points P-I, P-II, P-III, P-IV. The contact points P-I, P-II, P-III, P-IV are located in the contact zones 10 in a range of ?20?, in particular ?10? about the axis A.sub.S.

[0039] To ensure that the angular contact ball bearing 1 can absorb not only axial or radial loads, the contact points P-I, P-II, P-III, P-IV are always offset with respect to the axis A.sub.S. In this way, the ball 6 always has four contact points P-I, P-II, P-III, P-IV with the raceways 8, which are in each case located in the contact zones 10-I, 10-II, 10-III and 10-IV, as a result of which good radial load rigidity and a good load and pressure distribution and thus a low wear behaviour are achieved.

[0040] The exact arrangement of the contact points P-I, P-II, P-III, P-IV may differ, as shown in FIGS. 2 to 4.

[0041] In FIG. 2, the contact points P-I and P-II and also P-III and P-IV are arranged symmetrically about the axis A.sub.S. The connecting line L.sub.Va of the contact points P-I and P-II and the connecting line L.sub.Vi of the contact points P-III and P-IV therefore run parallel to each other and parallel to the ball axis of rotation A.sub.R. The region spanned by the connection of all of the contact points P-I, P-II, P-III and P-IV forms a rectangle.

[0042] Alternatively, as shown in FIGS. 3 and 4, the contact points P-I and P-II and also P-III and P-IV are arranged asymmetrically about the axis A.sub.S. The connecting line L.sub.Va of the contact points P-I and P-II and the connecting line L.sub.Vi of the contact points P-III and P-IV run obliquely with respect to each other and to the ball axis of rotation A.sub.R. The region spanned by the connection of all of the contact points P-I, P-II, P-III and P-IV forms a trapezoid. The connecting lines L.sub.Va and L.sub.Vi may intersect, depending on the formation of the asymmetric arrangement. In FIG. 4, for example, the connecting line L.sub.Va of the contact points P-I and P-II and the connecting line L.sub.Vi of the contact points P-III and P-IV intersect at the intersection X, which lies on the bearing axis A.sub.L.

[0043] By positioning the intersection X of the connecting lines L.sub.Va and L.sub.Vi above, on or below the bearing axis A.sub.L, the rolling kinematics and the contact stresses of the angular contact ball bearing arrangement 1 can be optimized for different load profiles, e.g. for an operation which is as slip-free as possible, or for high power transmission, or both.

[0044] The angular contact ball bearing arrangement 1 can be used as a double-row angular contact ball bearing in an O arrangement (FIG. 5) or in an X arrangement (FIG. 6). In the case of the O arrangement, the axes of rotation A.sub.R of the balls 6 intersect radially on the inside in the direction of the bearing axis of rotation A.sub.L, and, in the case of the X arrangement, the axes of rotation A.sub.R of the balls 6 intersect radially on the outside.

[0045] In the case of such a double-row angular contact ball bearing, the inner or outer rings 2, 4 can be designed as divided rings. In the case of the O arrangement of FIG. 5, the inner ring 2 is designed as a divided ring. In the case of the X arrangement of FIG. 6, the outer ring 4 is designed as a divided ring. In this case, a pretensioning mechanism, for example a screw connection, can be used to control the contact points P-I, P-II, P-III, P-IV or contact zones 10 between the ball 6 and the raceways 8. By pretensioning the respective ring 2, 4, the pretensioning of the contact points P-I, P-II, P-III, P-IV can be adjusted by adjusting the clearance between the parts of the divided ring 2, 4.

[0046] The angular contact ball bearing arrangement 1 can also be used as a linear bearing, as is illustrated in FIG. 7. Here, the angular contact ball bearing arrangement 1 is formed by two double-row angular contact ball bearing arrangements l and 1.

[0047] For the angular contact ball bearing arrangement 1, the first raceway element 2 is formed by a rail with raceways for both rows of balls 6 and the second raceway element by a carriage 12 and an element 4 separate therefrom, i.e. as a divided raceway element 4. For the angular contact ball bearing arrangement 1, the first raceway element 2 is also formed by the rail and additionally by an element 2 separate therefrom, i.e. as a divided raceway element 2, and the second raceway element is formed by the carriage 12 with raceways for the two rows of balls 6.

[0048] In this case too, the divided raceway elements 2 and 4 can be adjusted by a pretensioning element 14 in their pretensioning or their clearance, in order to correspondingly adjust the contact points P-I, P-II, P-III, P-IV or the contact zones 10-I, 10-II, 10-III, 10-IV.

[0049] Owing to the angular contact ball bearing described here, good radial and axial load rigidity and a low wear behaviour because of lower friction can be achieved.

LIST OF REFERENCE SIGNS

[0050] 1 angular contact ball bearing arrangement [0051] 2 first raceway element [0052] 4 second raceway element [0053] 6 balls [0054] 8 raceways [0055] 10 contact zones [0056] 12 carriage [0057] 14 pretensioning mechanism [0058] I, II, III, IV quadrants [0059] A.sub.L bearing axis of rotation [0060] A.sub.R ball axis of rotation [0061] A.sub.S axis perpendicular to the ball axis of rotation [0062] L.sub.Va connecting line of the contact points [0063] L.sub.Vi connecting line of the contact points [0064] M centre point of the radius of curvature [0065] P contact points [0066] R radius of curvature [0067] S intersection [0068] X intersection