Drive including a transmission driven by an electric motor

Patent metadata

Field	Value
Publication number	US-12435777-B2
Application number	US-202318846974-A
Country	US
Kind code	B2
Filing date	Feb 22, 2023
Priority date	Mar 15, 2022
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A drive includes a transmission driven by an electric motor. A drive shaft of the transmission has multiple eccentric regions with differing widths in the axial direction, in which the high points thereof are offset relative to one another in the circumferential direction. The respective eccentric region is radially surrounded by a respective cam disk region, e.g., of a housing part of the transmission. Respective rollers are accommodated in respective recesses of a cage and arranged with a radial degree of freedom. The cage is rotationally fixed to the output shaft of the transmission. The output shaft along with the cage is rotatably mounted both relative to the cam disk regions and relative to the drive shaft. During operation, the respective rollers are made to roll and/or slide on the respective cam disk region by the respective eccentric region. The eccentric regions are arranged behind one another in the axial direction such that the dynamic imbalance is minimized and/or eliminated.

First claim

The invention claimed is:

1. A drive, comprising:
a transmission adapted to be driven by an electric motor, the transmission including a drive shaft having eccentric regions, each eccentric region being radially surrounded by a respective cam disk region of a first housing part of the transmission, respective rollers being accommodated in respective recesses of a cage and arranged with a radial degree of freedom;
wherein the cage is rotationally fixed to an output shaft of the transmission;
wherein the first housing part is connected to a second housing part;
wherein the output shaft along with the cage is rotatably mounted both relative to the cam disk regions and relative to the drive shaft;
wherein the output shaft has a wedge-shaped and/or V-shaped groove that is uninterrupted and/or fully circumferential in a circumferential direction, in which rolling bodies are accommodated;
wherein a V-shaped recess is delimitated in an axial direction by the first housing part and against the axial direction by a second housing part.

2. The drive according to claim 1 , wherein the drive shaft is arranged as a hollow shaft, at least two of the eccentric regions having differing widths in the axial direction, high points of the at least two of the eccentric regions being offset relative to one another in the circumferential direction;
wherein the respective recesses radially pass through the cage and are evenly spaced from one another in the circumferential direction;
wherein a first rolling region of the rolling body is arranged on a flank of the wedge-shaped or V-shaped groove and a second rolling region of the rolling body is arranged on the first housing part or on the second housing part;
wherein the V-shaped recess is arranged radially outside the V-shaped groove;
wherein the second housing part includes axial bores adapted to connect to a device to be driven by the transmission of the drive;
wherein the output shaft includes axial bores at an axial end region facing away from the cage and adapted to connect to a rotatably mounted part of the device to be driven;
wherein the rolling bodies are adapted to roll and/or slide on the respective cam disk region by the respective eccentric region during operation of the drive;
wherein widths B_i of the eccentric regions and circumferential angle positions α_i of the high points associated with the respective eccentric region are formed such that a sum of all products B_i * cos(α_i) is eliminated and that a sum of all products B_i * sin(α_i) is eliminated, i represents a number of the eccentric regions;
wherein the eccentric regions are arranged behind one another in the axial direction to minimize and/or eliminate dynamic imbalance.

3. The drive according to claim 1 , wherein a stiffening ring is provided on the cage on a side facing away from the axial bores of the output shaft, the stiffening ring being aligned coaxially to the cage and coaxially to the output shaft, a radial wall thickness of the cage in a region covered by the stiffening ring in the axial direction being greater than a wall thickness of the cage outside the region.

4. The drive according to claim 1 , wherein first recesses of the cage are rectangular in shape, relief notches project in the axial direction in corner regions of the rectangular recesses, and a distance between two relief notches measured in the circumferential direction decreases monotonically in the axial direction and/or with increasing distance from the rectangular recesses.

5. The drive according to claim 1 , wherein first recesses of the cage are rectangular slot-shaped, a respective axial end region of the slot-shaped recess is rounded and/or semicircular, on a first spacer ring, radially projecting nubs project into the first recesses and axially delimit first rollers that are accommodated in the first recesses.

6. The drive according to claim 5 , wherein a first one of the nubs of the first spacer ring projects into the first recess and axially delimits a respective first roller accommodated in the first recess, and a second one of the nubs of the first spacer ring next adjacent to the first one of the nubs of the first spacer ring projects into a respective second recess of the cage and axially delimits a second roller accommodated in the second recess, the second recess being axially spaced from the first recess.

7. The drive according to claim 1 , wherein an inner radius of a first cam disk region depends periodically on a circumferential angle, and the first cam disk region in the axial direction includes a region covered by a respective first roller in the axial direction.

8. The drive according to claim 1 , wherein an outer radius of the drive shaft in the respective eccentric region depends on a circumferential angle.

9. The drive according to claim 1 , wherein an axial region covered by the respective eccentric region at least overlaps with an axial region covered by the cam disk region, the cam disk region touching the same roller as the respective eccentric region.

10. The drive according to claim 1 , wherein the drive shaft is rotationally fixed to a rotor shaft of the electric motor and/or is adapted to be driven by the rotor shaft of the electric motor via at least one gear stage, a first toothed part being rotationally fixed to the rotor shaft and a second toothed part being rotationally fixed to the drive shaft.

11. The drive according to claim 1 , wherein the cam disk regions are arranged on an inside of the first housing part of the transmission, the first housing part is connected to a second housing part, rolling bodies of a bearing arrangement of the output shaft are delimited by the first housing part, by the second housing part, and by the output shaft.

12. The drive according to claim 11 , wherein the output shaft has a V-shaped annular groove arranged fully circumferential in the circumferential direction, i in which the rolling bodies are accommodated, and a further V-shaped recess arranged fully circumferential in the circumferential direction, in which the rolling bodies are accommodated and which has an orientation reversed to the V-shaped annular groove, is formed and/or edged by the first and second housing part.

13. The drive according to claim 1 , wherein a bearing is arranged on a first one of the eccentric regions, on which first rollers roll and/or slide directly or on which a ring is fitted, on which the first rollers roll and/or slide.

14. The drive according to claim 1 , wherein an inner radius of the respective cam disk region depends periodically on a circumferential angle, an outer radius of the shaft in the respective eccentric region depends on circumferential angle, an axial region covered by the respective eccentric region at least overlaps with an axial region covered by the respective associated cam disk region, and/or a respective bearing is and on the respective eccentric region.

15. The drive according to claim 1 , wherein the cam disk regions are arranged in the first housing part, which is connected to the second housing part, in which a bearing arrangement is accommodated that rotatably supports the output shaft, a respective inner ring of the bearing arrangement being accommodated on the output shaft and a respective outer ring of the bearing being accommodated in the second housing part.

16. The drive according to claim 1 , wherein a shaft seal ring is arranged in the output shaft, the shaft seal ring sealing toward the drive shaft, a further shaft seal ring being arranged in the second housing part, the further shaft seal ring sealing toward the output shaft.

Assignees

• Sew Eurodrive Gmbh & Co Kg

Inventors

• Lutz Markus
• Schütterle Ingo
• Koker Torsten
• Wöppermann Markus
• Haller Sascha

Classifications

• F16H2061/2869

  Cam or crank gearing · CPC title

• F16H29/04

  in which the transmission ratio is changed by adjustment of a crank, an eccentric, a wobble-plate, or a cam, on one of the shafts · CPC title

• F16H63/18

  the final actuating mechanism comprising cams · CPC title

• F16H2057/02034

  Gearboxes combined or connected with electric machines · CPC title

• F16H57/029

  characterised by means for sealing the gearboxes, e.g. to improve airtightness · CPC title