PLANETARY ROLLER SCREW DRIVE

Abstract

The disclosure relates to a planetary roller screw drive comprising a threaded spindle nut, a horizontal threaded spindled, a plurality of planetary rolling elements having a planetary rolling element profile, and at least two planetary guide rings. The threaded spindle is arranged concentrically in the planetary guide rings and the spindle nut. The planetary guide rings can be rotated relative to the threaded spindle and the planetary rolling elements are mounted so as to be rotatable about their associated planetary rolling element axis in the planetary guide rings and inside the spindle nut. The planetary rolling element profile of the planetary rolling elements meshes with the threaded spindle. The planetary guide rings are connected to a housing case for conjoint rotation, and the housing case has a housing case lateral surface on which a toothing is formed for coupling in a geared manner to with a continuous traction mechanism.

Claims

1. A planetary roller screw drive configured to convert rotational movement to translational movement, the planetary roller screw drive comprising: a threaded spindle nut, a horizontal threaded spindle, a plurality of planetary rolling elements having a planetary rolling element thread configured to mesh with the horizontal threaded spindle, and at least two planetary guide rings rotatable relative to the horizontal threaded spindle, and the horizontal threaded spindle arranged concentrically within the at least two planetary guide rings and the threaded spindle nut, and each of the plurality of planetary rolling elements mounted so as to be rotatable about a corresponding one of a planetary rolling element axis within the planetary guide rings, and rotation of the at least two planetary guide rings causes the plurality of planetary rolling elements to rotate about: i) the planetary rolling element axes and, ii) the horizontal threaded spindle (4), wherein the planetary guide rings are fixed to a housing case for conjoint rotation therewith, and the housing case includes a housing case lateral surfaced formed with toothing configured for coupling with a continuous traction mechanism.

2. The planetary roller screw drive of claim 1, characterized in that the toothing is arranged axially between two housing case rims.

3. The planetary roller screw drive of claim 1, wherein the at least two planetary guide rings and the threaded spindle nut are configured to be rotatable relative to one another via a first group of rolling bearings.

4. The planetary roller screw drive of claim 3, wherein each of the plurality of planetary rolling elements have a second group of rolling bearings arranged on an end face.

5. The planetary roller screw drive of claim 1, wherein each of the plurality of planetary rolling elements have, at each distal end, a planetary rolling element bearing journal configured to couple each of the plurality of planetary rolling elements to the threaded spindle nut.

6. The planetary roller screw drive of claim 1, wherein the housing case is constructed from plastic.

7. The planetary roller scrive drive of claim 5, wherein each of the planetary rolling element journals is received by a corresponding bearing bore arranged within the at least two planetary guide rings.

8. The planetary roller screw drive of claim 1, wherein the planetary guide rings are fixed to the housing case via a press fit.

9. The planetary roller screw drive of claim 1, wherein the housing case lateral surface is offset relative to the housing case so that two housing case rims are formed.

10. The planetary roller screw drive of claim 1, wherein the at least two planetary guide rings have a larger outer diameter than the threaded spindle nut.

11. A planetary roller screw drive configured to convert rotational movement to translational movement, the planetary roller screw drive comprising: a threaded spindle nut, a threaded spindle extending through the threaded spindle nut, at least two planetary guide rings rotatable relative to the threaded spindle and the threaded spindle nut, a plurality of threaded planetary rolling elements mounted within the at least two planetary guide rings and configured to mesh with the threaded spindle, each of the plurality of threaded planetary rolling elements configured to rotate about a corresponding one of a planetary rolling element axis, and a housing case fixed to the at least two planetary guide rings for conjoint rotation therewith, the housing case configured for coupling with a continuous traction mechanism, and rotation of the at least two planetary guide rings causes the plurality of planetary threaded rolling elements to rotate about: i) the planetary rolling element axes, and ii) the threaded spindle.

12. The planetary roller screw drive of claim 11, wherein the at least two planetary guide rings are rotatable relative to the threaded spindle via a first group of rolling bearings.

13. The planetary roller screw drive of claim 12, wherein the first group of rolling bearings is arranged between the threaded spindle nut and the at least two planetary guide rings in an axial direction.

14. The planetary roller screw drive of claim 13, further comprising a second group of rolling bearings arranged on an end face of each of the at least two planetary guide rings.

15. The planetary roller screw drive of claim 11, wherein the at least two planetary guide rings have a larger outer diameter than the threaded spindle nut.

16. The planetary roller screw drive of claim 11, wherein the at least two planetary guide rings include bearing bores configured to receive the plurality of threaded planetary rolling elements, and the plurality of threaded planetary rolling elements are rotatable relative to the bearing bores.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the figures:

[0030] FIG. 1 shows an embodiment of the planetary roller screw drive according to the disclosure in a schematic cross-sectional view.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a planetary roller screw drive 2. The planetary roller screw drive 2 has a threaded spindle nut 3, a horizontal threaded spindle 4, a plurality of planetary rolling elements 5 with a planetary rolling element profile 6, and the two planetary guide rings 7.

[0032] By means of the planetary roller screw drive 2, a rotational movement is converted into a translational movement. This is explained in more detail below. The horizontal threaded spindle 4 is concentrically arranged in the planetary guide rings 7 and the threaded spindle nut 3. The planetary guide rings 7 are rotatable relative to the horizontal threaded spindle 4 and the planetary rolling elements 5 are mounted so as to be rotatable about their respective planetary rolling element axis 8 in the planetary guide rings 7 and within the threaded spindle nut 3. The planetary rolling element profile 6 of the planetary rolling elements 5 meshes with the horizontal threaded spindle 4 so that rotation of the horizontal threaded spindle 4 causes rotation of the planetary rolling elements 5 about their planetary rolling element axis 8 and rotation of the planetary rolling elements 5 about the horizontal threaded spindle 4.

[0033] The planetary rolling elements 5 each have a planetary rolling element bearing journal 15 at their distal ends, which is coupled in a geared manner to the threaded spindle nut 3, for example by means of a suitable corresponding profiling such as an internal thread/external thread combination. As a result, the planetary rolling elements are coupled in a geared manner to both the horizontal threaded spindle 4 and the threaded spindle nut 3.

[0034] The planetary guide rings 7 have a larger diameter than the threaded spindle nut 3 and are connected for conjoint rotation with the housing case 9 so that the threaded spindle nut 3 is received within the housing case 9. The housing case 9 has a housing case lateral surface 10 on which the toothing 11 is designed for coupling in a geared manner, in particular with a continuous traction mechanism not shown. FIG. 1 also shows that the housing case lateral surface 10 is formed on the housing case 9 offset radially in the direction of the horizontal threaded spindle 4, so that two housing case rims 12 are formed on the housing case 9 for axial guidance purposes, for example of the continuous traction mechanism not shown.

[0035] The planetary guide rings 7 have unspecified receptacles for the planetary rolling element bearing journals 15, whereby it is achieved that the planetary rolling elements 5 rotate around the horizontal threaded spindle 4 when the planetary guide rings 7 are rotated. Since the planetary guide rings 7 are connected for conjoint rotation via the housing case 9, the planetary guide rings 7 rotate in synchronization with one another.

[0036] The planetary guide rings 7 and the threaded spindle nut 3 are arranged to rotate relative to one another via a first group of rolling bearings 13. The planetary guide rings 7 have a second group of rolling bearings 14 on their respective end faces. On the one hand, these bearing arrangements support the axial forces of the horizontal threaded spindle 4 and the radial forces by means of a belt drive or a gear wheel, for example. The axial force on the planetary guide rings 7 is absorbed by the second group of rolling bearings 14, which also ensure contact with the surrounding structure. In this way, the axial and radial forces can be absorbed and transmitted to the surrounding structure, the planetary roller screw drive 2 remains rotatable and the radial forces do not affect the horizontal threaded spindle 4 and the planetary rolling elements 5.

[0037] The planetary roller screw drive 2 can be used in particular for rear axle steering in motor vehicles.

[0038] The disclosure is not limited to the embodiments shown in the figures. The above description is therefore not to be regarded as restrictive, but rather as explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the disclosure. This does not exclude the presence of further features. If the patent claims and the above description define “first” and “second” features, this designation serves to distinguish between two features of the same type without defining an order of precedence.

LIST OF REFERENCE SYMBOLS

[0039] 2 Planetary roller screw drive [0040] 3 Threaded spindle nut [0041] 4 Horizontal threaded spindle [0042] 5 Planetary rolling elements [0043] 6 Planetary rolling element profile [0044] 7 Planetary guide rings [0045] 8 Planetary rolling element axis [0046] 9 Housing case [0047] 10 Housing case lateral surface [0048] 11 Toothing [0049] 12 Housing case rim [0050] 13 First group of rolling bearings [0051] 14 Second group of rolling bearings [0052] 15 Planetary rolling element bearing journal