DRIVE DEVICE FOR AN ACTUATOR

Abstract

A drive device for an actuator for a brake device of a motor vehicle. The drive device has an electric machine having a rotor rotatably mounted in a housing and a stator fixed to the housing. A bearing shield is situated in the housing that has an axially extending sleeve-shaped bearing segment for the rotatable bearing of a drive shaft, which bears the rotor. The bearing shield has an axially extending sleeve-shaped retaining segment held with a frictional fit in a sleeve-shaped end segment of the housing and has a diameter that is greater than the diameter of the bearing segment. A radially extending annular disk-shaped floor segment of the bearing shield is between the retaining segment and the bearing segment. The retaining segment has a first axial partial segment connected to the floor segment, and a second partial segment connected to the first partial segment.

Claims

1-10 (canceled)

11. A drive device for an actuator, comprising: an electric machine including: a rotor rotatably mounted in a housing; a stator fixed to the housing; and a bearing shield situated in the housing that has at least one axially extending sleeve-shaped bearing segment for the rotatable bearing of a drive shaft, which bears the rotor of the electric machine, the bearing shield having an axially extending sleeve-shaped retaining segment that is held with a frictional fit in a sleeve-shaped end segment of the housing and that has a diameter that is greater than a diameter of the bearing segment, at least one radially extending and annular disk-shaped floor segment of the bearing shield being formed between the retaining segment and the bearing segment; wherein the retaining segment has a first axial partial segment, connected to the floor segment, having a first outer diameter, and a second partial segment, connected to the first partial segment, having a second outer diameter, the second outer diameter being larger than the first outer diameter.

12. The drive device as recited in claim 11, wherein the drive device is for a brake device of a motor vehicle.

13. The drive device as recited in claim 11, wherein the end segment of the housing is axially at least as long as the retaining segment of the bearing shield.

14. The drive device as recited in claim 11, wherein the end segment of the housing has a continuously constant inner diameter.

15. The drive device as recited in claim 11, wherein the retaining segment of the bearing shield has a continuously constant radial extension.

16. The drive device as recited in claim 11, wherein the second partial segment extends up to a free end face of the bearing shield.

17. The drive device as recited in claim 16, wherein the free end face of the bearing shield is situated axially at the height of a free end of the end segment of the housing.

18. The drive device as recited in claim 17, wherein a radially outward-protruding mounting flange for fastening the housing to the actuator is situated on the free end of the end segment of the housing.

19. The drive device as recited in claim 18, wherein the mounting flange is a collar made in one piece with the housing.

20. The drive device as recited in claim 18, wherein the end face of the bearing shield terminates flush with an end face, assigned to the actuator, of the mounting flange.

21. The drive device as recited in claim 18, wherein a silicon sealing element, extends over at least regions of, respectively, the end face of the bearing shield and an end surface of the mounting flange.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows an advantageous drive device in a simplified longitudinal sectional view, according to an example embodiment of the present invention.

[0015] FIG. 2 shows an enlarged detail of the drive device, according to an example embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0016] FIG. 1 shows, in a simplified longitudinal sectional view, an advantageous drive device 1 for an actuator 2 or consumer (not shown) that is capable of being driven by the drive device. For this purpose, drive device 1 has an electric machine 3 situated in a housing 4. Housing 4 is made substantially cup-shaped, and has a receptacle opening 5 at an end face. Electric machine 3 has a stator 6 situated fixedly in housing 4, and has a rotor 7 assigned to stator 6. Rotor 7 is situated on a drive shaft 8 that is mounted rotatably in housing 4. In particular, drive shaft 8 is rotatably mounted by two or more roller bearings 18. One of the roller bearings 18, shown in the Figure, is situated on a bearing shield 9 that is largely situated inside housing 4. While, according to the present exemplary embodiment, a roller bearing 18 is shown and described, according to another exemplary embodiment the mounting of drive shaft 8 in bearing shield 9 can alternatively be provided by some other type of pivot bearing, such as a magnet bearing, hydraulic bearing, pneumatic bearing, or friction bearing.

[0017] Bearing shield 9 is made of metal as a deep-drawn part, and has a sleeve-shaped first segment 10 that acts as bearing segment for accommodating and situating the above-named roller bearing 18, and has a second segment 11 and a third segment 12, the segments 10 to 12 differing in that segment 10 has a first diameter D1 that is smaller than a diameter D2 of second segment 11, and third segment 12 having a diameter D3 that is larger than diameter D2. The segments succeed one another axially in the indicated sequence 10, 11, 12. Second segment 11 is used in particular to accommodate a drive (not shown), in particular a planetary drive, which is used to translate rotational speed and/or torque at consumer 2.

[0018] Third segment 12 forms a retaining segment 13 by which bearing shield 9 is held in housing 4 of electric machine 3.

[0019] Housing 4 has an end segment 14 that forms opening 5. End segment 14, and thus also opening 5, have an inner diameter that is slightly smaller than an outer diameter of retaining segment 12 of bearing shield 9, so that there is a radial press fit between bearing shield 9 and housing 4 in the area of retaining segment 13 and end segment 14, by which press fit bearing shield 9 is fastened in housing 4. Here, end segment 14 has an axial length that is at least as long as the axial length of segment 12, or of retaining segment 13, of bearing shield 9, so that this shield can be situated partially or completely in housing 4.

[0020] Moreover, housing 4 has, at the free end of end segment 14, a radially outward-protruding collar in the form of a mounting flange 15. Mounting flange 15 stands out radially from housing 4 and forms mounting flange 15 of drive device 1. For this purpose, mounting flange 15 has for example openings 16 distributed uniformly around its circumference, of which only one is shown in the Figure, through which fastening screws can be used to assemble drive device 1 to consumer 2. Drive device 1 is thus capable of being situated, or fastened, as a whole on consumer 2 using mounting flange 15 of bearing shield 9.

[0021] As can be seen in FIG. 1, the bearing shield terminates, with retaining segment 13, flush with mounting flange 15 of housing 4, so that a free end face 20 of retaining segment 13 is situated flush with an end surface 21 of housing 4 on mounting flange 15. Optionally, a sealing element, in particular a silicon sealing element 22, is provided that lies on the end face of drive device 1 in such a way that it extends at least over regions both of end face 20 and also of end surface 21, so that a particularly tight connection is ensured between bearing shield 9 and housing 4, and in addition a tight connection is also provided between drive device 1 on the one hand and consumer 2, on which mounting flange 15 is to be situated, on the other hand.

[0022] Retaining segment 13 of bearing shield 9 has a first partial segment 23 and a second partial segment 24 that extend one after the other axially from an annular disk-shaped floor segment 25 that extends substantially radially between segment 11 and retaining segment 13. Here, first partial segment 23 goes out from floor segment 25, i.e. substantially stands out in perpendicular or axial fashion therefrom, and partial segment 24 connects to partial segment 23, and ends in end face 20.

[0023] The two partial segments 23, 24 differ in that the outer diameter of partial segment 24 is greater than the outer diameter of partial segment 23, so that the press fit between housing 4 and bearing shield 9 exists only in the region of second partial segment 24. As a result, the contact point between housing 4 and bearing shield 9 is at a distance from floor segment 25. As a result, in the region of partial segment 23 preferably no, or only small, radial forces, which could also act on floor segment 25, are transmitted to bearing shield 9.

[0024] Here, the advantageous realization of drive device 1 brings it about that through the shrinking of housing 4 onto bearing shield 9 in the region of partial segment 24, no forces act on bearing shield 9 in such a way that the orientation of floor segment 25 is moved out of a plane perpendicular to the axis of rotation of drive shaft 8. Thus, using simple means, it is ensured that a misalignment in particular of the bearing segment (segment 10) is prevented. In addition, there results a simplified geometry of housing 4, having an inner diameter that remains the same, or constant, at least in end segment 14. If housing 4 is realized as a deep-drawn part, the deep-drawing tool can thus make do with fewer drawing stages, thus achieving a simplified manufacture.

[0025] Moreover, the overall large axial length of retaining segment 13 also brings about a large radial sealing surface between bearing shield 9 and housing 4.