Steering system with pivot bearing

Abstract

A steering system for a motor vehicle has a worm gear set, comprising a worm wheel and a worm shaft, wherein the worm shaft is rotatably mounted at least one bearing point in a housing of the worm gear set by means of a pivot bearing. The pivot bearing has an increased load capacity compared to a pivot bearing with a single-row standard deep groove ball bearing. A pivot bearing for a steering system has an inner ring and an outer ring, wherein a plurality of rolling elements is arranged between the inner ring and the outer ring. One of the bearing rings is designed as a full ring and the other bearing ring as a split bearing ring, the split bearing ring having a first ring element and a second ring element.

Claims

1. A steering system for a motor vehicle, the steering system comprising a worm wheel and a worm shaft, the worm shaft being mounted rotatably by a pivot bearing at at least one bearing point in a housing of the worm gear set, wherein the pivot bearing has an outer ring and a split inner ring, the split inner ring having a first ring element and a second ring element.

2. The steering system according to claim 1, wherein outer shoulders in an axial direction on the split inner ring or on the outer ring have a shoulder height with a shoulder height factor greater than 0.2.

3. The steering system according to claim 1, wherein the pivot bearing is a ball bearing having a larger number of balls than could be inserted into a ball bearing of the same diameter and no split ring.

4. The steering system according to claim 1, wherein the steering system has electrical steering assistance which amplifies the steering forces or steering torques.

5. A pivot bearing for a steering system having an inner ring and an outer ring, a plurality of rolling elements being arranged between the inner ring and the outer ring, wherein one of the inner and outer rings is a full ring and another of the inner and outer rings is a split bearing ring, wherein the split bearing ring has a first ring element and a second ring element.

6. The pivot bearing according to claim 5, wherein shoulders on the split inner ring have a shoulder height with a shoulder height factor greater than 0.2.

7. The pivot bearing according to claim 5, wherein a track geometry is designed as a four-point bearing with a pressure angle greater than 10°.

8. A steering system comprising: a housing; a worm wheel; and a worm shaft engaging the worm wheel and pivotably mounted in the housing by a pivot bearing, the pivot bearing has an outer ring, a first inner ring, a second inner ring, and a plurality of balls retained between the outer ring, the first inner ring, and the second inner ring.

9. The steering system according to claim 8, wherein the first inner ring and the second inner ring have a shoulder height factor greater than 0.2.

10. The steering system according to claim 8, wherein the balls of the plurality of balls contact the outer ring, the first inner ring, and the second inner ring at a pressure angle greater than 10°.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following, the steering system is explained in more detail by means of a preferred exemplary embodiment and the corresponding drawings. In the drawings:

[0019] FIG. 1 shows an exemplary embodiment of a steering system having a pivot bearing;

[0020] FIG. 2 shows a preferred exemplary embodiment of a pivot bearing for a steering system.

DETAILED DESCRIPTION

[0021] In FIG. 1 is shown an exemplary embodiment of a steering system 1 with a pivot bearing 6. The steering system has a worm gear set 2 with which a steering torque is transmitted from a worm shaft 4 to a worm wheel 3. For this purpose, a toothing 7 is formed on the worm wheel 3, which meshes with a toothed section 8 of the worm shaft 4. The worm shaft 4 is mounted rotatably on at least one bearing point 5, preferably on at least two bearing points 5, in a housing of the worm gear set 2. The steering system 1 is preferably designed as an electrically-assisted steering system 1. For this purpose, the steering system 1 comprises an electrical steering assistance system 9 with which the steering forces of the driver are supported to change the steering angle. The worm shaft 4 is mounted on the drive side by means of a pivot bearing 6. On the side facing away from the drive side, the worm shaft 5 is mounted by means of a second rolling bearing 24, which is designed as a floating bearing 25. The floating bearing 25 is pressed radially onto the worm shaft 5 by means of a preloading element so that the play of the toothing between the toothing section 8 on the worm shaft 5 and the toothing 7 on the worm wheel 3 is reduced to zero.

[0022] In FIG. 2, a pivot bearing 6 is shown as a special bearing 10 for such a steering system 1. The pivot bearing 6 has a split inner ring 21 which comprises a first ring element 22 and a second ring element 23. The pivot bearing 6 also has an outer ring 12, which is designed as a one-piece outer ring 12. Between the split inner ring 21 and the outer ring 12 there are a plurality of rolling elements 17, which in this exemplary embodiment are designed as balls 18. However, other known forms of rolling elements, in particular tapered rollers, are also possible. A race for the rolling elements 17 is formed on the outer ring 12 to enable the rolling elements to roll on the outer ring 12 with as little friction as possible. A first race 15 for the rolling elements is formed on the first ring element 22, and a second race 16 is formed on the second ring element 23 which guides the rolling elements 17 together with the race on the outer ring 12. The outer ring 12 of the pivot bearing 6 is tiltably received in a pivot ring of the pivot bearing 6, which enables a pivoting or tilting movement and thus an axial compensation in the pivot bearing 6. For this purpose, the outer ring 12 has a convex shape on the radially outer surface thereof and the pivot ring has a concave shape on the radially inner surface thereof so that a compensating movement is possible between the outer ring 12 and the pivot ring. The pivot bearing 6 also has a cage 13 which positions the rolling elements 17 with respect to one another. In addition, the pivot bearing 6 comprises sealing elements 14, which prevent dirt from penetrating into the region of the races 15, 16 of the rolling elements 17 and are intended to prevent lubricant from escaping from this region. Due to the split inner ring 21, the shoulders on the two ring elements 22, 23 can be made higher than a one-piece inner ring 11, whereby the load capacity of the pivot bearing increases. In addition, it is possible to use more balls and/or larger balls with the same diameter as a standard deep groove ball bearing since the inner ring 21 can be split for filling the balls 18 and the filling of the balls 18 is made easier in this way. In addition, the higher shoulders on the two ring elements 22, 23 of the split inner ring 21 allow greater axial loads to be transmitted. The assembly process for rolling bearings with a split inner ring differs as follows from an assembly process for a single-row rolling bearing with one-piece bearing rings 11, 12. The outer ring 12 and the first ring element 22 of the split inner ring 21 are filled with the rolling elements 17, the cage 13 is mounted, and only then is the second ring element 23 of the split inner ring 21 attached.

LIST OF REFERENCE SYMBOLS

[0023] 1 Steering system [0024] 2 Worm gear set [0025] 3 Worm wheel [0026] 4 Worm shaft [0027] 5 Bearing point [0028] 6 Pivot bearing [0029] 7 Toothing [0030] 8 Toothed section [0031] 9 Electric steering assistance [0032] 10 Special bearing [0033] 11 Inner ring [0034] 12 Outer ring [0035] 13 Cage [0036] 14 Sealing element [0037] 15 First race [0038] 16 Second race [0039] 17 Rolling element [0040] 18 Ball [0041] 21 Split inner ring [0042] 22 First ring element [0043] 23 Second ring element [0044] 24 Rolling bearing [0045] 25 Floating bearing