Gear unit having a first and a second housing part

Abstract

A gear unit is described as having a first and a second housing part, an intermediate shaft of the gear unit being mounted via two bearings in a bushing accommodating the bearings, the bushing centering the first housing part against the second housing part.

Claims

1. A gear unit, comprising: a housing including a first housing part and a second housing part; a bushing; and two bearings accommodated in the bushing and adapted to rotatably support a shaft in the housing; wherein the bushing is at least partially interference-fit to the first housing part and at least partially slip-fit to the second housing part.

2. The gear unit according to claim 1, wherein the bushing centers the first housing part against the second housing part.

3. The gear unit according to claim 1, wherein the bushing is at least partially slip-fit to the first housing part and at least partially interference-fit to the second housing part.

4. The gear unit according to claim 1, wherein the bushing projects at least partially from the first housing part.

5. The gear unit according to claim 4, wherein a portion of the bushing that project from the first housing part is partially slip-fit to the second housing part and partially interference-fit to the second housing part.

6. The gear unit according to claim 1, wherein the bushing includes a first axial region arranged as a slip-fit region and a second axial region arranged as an interference-fit region.

7. The gear unit according to claim 6, wherein the slip-fit region is arranged at an axial end region of the bushing and the interference-fit region is located axially inward of the slip-fit region.

8. The gear unit according to claim 1, wherein the bushing has an outer sleeve section that abuts against accommodation areas of the first and second housing parts.

9. The gear unit according to claim 1, wherein the bushing has an inner sleeve section which accommodates a first bearing in a first axial part and a second bearing in a second axial part, wherein a crosspiece segment is disposed axially between the first and second axial parts whose smallest radial distance is less than a smallest radial distance of the first axial part or the second axial part.

10. The gear unit according to claim 8, wherein the bushing has an inner sleeve section which accommodates a first bearing in a first axial part and a second bearing in a second axial part, wherein a crosspiece segment is disposed axially between the first and second axial parts whose smallest radial distance is less than a smallest radial distance of the first axial part or the second axial part.

11. The gear unit according to claim 10, wherein the inner sleeve section and the outer sleeve section are joined via support ribs that are set apart from each other.

12. The gear unit according to claim 11, wherein the support ribs are evenly spaced from each other in a circumferential direction.

13. The gear unit according to claim 1, wherein the bearings are tapered roller bearings in an O-configuration, an X-configuration, and/or a tandem configuration.

14. The gear unit according to claim 1, wherein: the intermediate shaft is joined in rotatably fixed manner to a first toothing part or has a corresponding toothing section, so that a first axial bearing is bounded axially by the toothing part or the toothing section; and on an opposite axial side of the bushing, a further toothing part is joined in a rotatably fixed manner to the intermediate shaft and bounds the other bearing axially.

15. The gear unit according to claim 14, wherein the further toothing part is bounded axially by a retaining ring.

16. The gear unit according to claim 1, wherein the bushing is pressed into an accommodation area of the first housing part and into an accommodation area, situated coaxially relative to the accommodation area of the first part, of the second housing part.

17. The gear unit according to claim 1, wherein the first and second housing parts are imperviously joined.

18. The gear unit according to claim 16, wherein an annular spatial area adapted to receive adhesive is located between one of the housing parts and the bushing.

19. The gear unit according to claim 18, wherein the spatial area is delimited by a depression in the bushing and by an accommodation area of one of the first housing part and the second housing part for the bushing.

20. The gear unit according to claim 18, wherein an adhesive is provided in the annular spatial area and rotatably fixes the one of the housing parts and the bushing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a sectional view through a gear unit according to the present invention having a bushing 11.

(2) FIG. 2 shows bushing 11 in an oblique view.

(3) FIG. 3 shows bushing 11 in plan view.

(4) FIG. 4 shows bushing 11 in sectional view.

DETAILED DESCRIPTION

(5) The housing of the gear unit has at least two housing parts 12, 14, which are centered relative to each other by bushing 11.

(6) Bushing 11 accommodates two bearings 8, 10, via which an intermediate shaft 18 is mounted that, at its axial end area on the input side, is joined in rotatably fixed manner to a gear wheel 20, which is in mesh with an input gear wheel 16 that is joined in rotatably fixed manner to an input shaft 17, especially a rotor of a driving electric motor, not shown. Gear wheel 16, together with shaft 17, is supported in the housing of the driving device, especially electric motor. The housing of the driving device is joined to first housing part 12, a centering means, especially a centering collar, being formed here on first housing part 12.

(7) At its other axial end area, intermediate shaft 18 is joined in rotatably fixed manner to bevel pinion 9. Alternatively, intermediate shaft 18 is realized in one piece with bevel pinion 9, so that the gear teeth of the bevel pinion are Incorporated in a section of intermediate shaft 18.

(8) Bevel pinion 9 is in mesh with bevel-gear wheel 13, which is supported via bearings in second housing part 14 or in a housing part joined to second housing part 14.

(9) The inner ring of first bearing 10 of bushing 11 abuts against a shaft offset, especially against a collar, of intermediate shaft 18.

(10) The outer ring of first bearing 10 abuts against an inner step of the inner wall of bushing 11.

(11) The outer ring of second bearing 8 likewise abuts against an inner step of the inner wall of bushing 11. In this context, the two inner steps indicated are formed by a radially inwards extending, ring-shaped segment located on the inner wall of bushing 11, the segment being set apart radially from intermediate shaft 18.

(12) The inner ring of second bearing 8 abuts against gear wheel 20, which cooperates with a retaining ring 19 disposed on the side of gear wheel 20 facing away from bearing 8.

(13) Thus, by way of example, bearings 8, 10 may be implemented as tapered roller bearings and are retained so as to be bounded axially.

(14) In the case of a two-piece construction of bevel pinion 9 and intermediate shaft 18, an axial limiting means is disposed between bevel pinion 9 and intermediate shaft 18.

(15) Bushing 11 has a depression 7 on its outer side, and is accommodated in the cylindrical, preferably non-graduated accommodation areas of housing parts 12, 14. Preferably, the accommodation areas are produced as a bore hole.

(16) Consequently, depression 7, together with the wall of the accommodation area of first housing part 12, delimits an annular spatial area in which adhesive may be introduced. Thus, the adhesive then ensures a rotatably-fixed connection between first housing part 12 and bushing 11.

(17) In addition, bushing 11 has on its outer surface, thus, on the outer surface of outer sleeve section 22, a first axial part which is realized as insertion-fit area 1 and which facilitates the insertion of bushing 11 into the accommodation area, and an axial part adjacent to it which is effective as interference-fit area 2, so that a high static friction is obtained.

(18) Preferably, the accommodation area of housing part 12 is additionally shrunk thermally onto the bushing. To that end, a temperature difference is provided between the bushing and housing part 12 during the joining process.

(19) In the same way, the bushing also has an insertion-fit area and an interference-fit area which are effective upon joining with second housing part 14.

(20) Bushing 11 has an inner sleeve section 21 and an outer sleeve section 22, inner sleeve section 21 accommodating the respective outer rings of bearings 8, 10, and outer sleeve section 22 contacting the accommodation areas of housing parts 12, 14.

(21) In the radial clearance area between the two sleeve sections 21, 22, radially extending, spoke-like support ribs 4 are situated, so that an axial through-opening 3 is present between each two next-adjacent support ribs in the circumferential direction. In this way, oil is able to be passed through from the axially front to the axially rear side of bushing 11.

(22) Support ribs 4, outer sleeve section 22 and inner sleeve section 21 are preferably realized in one piece.

(23) Bushing 11 is preferably made of steel or a metal such as aluminum.

(24) In a further exemplary embodiment of the present invention, instead of tapered roller bearings 8, 10 shown, disposed in O-configuration or tandem configuration, other bearings such as ball roller bearings are used.

LIST OF REFERENCE CHARACTERS

(25) 1. Insertion-fit area 2. Interference-fit area 3. Opening, through-hole for oil exchange 4. Support rib 5. Line of symmetry 6. Bearing housing 7. Depression to form a spatial area for adhesive bonding as a safeguard against twisting 8. Bearing 9. Bevel pinion 10. Bearing 11. Bushing 12. First housing part 13. Bevel-gear wheel 14. Second housing part 16. Gear wheel 17. Shaft, particularly input shaft, especially rotor of an electric motor 18. Intermediate shaft 19. Retaining ring 20. Gear wheel 21. Inner sleeve section 22. Outer sleeve section