Drive unit and combination of a drive unit with a unit to be driven

Abstract

A drive unit with an electric motor and a speed-transforming transmission connected in a rotationally driven manner to a power take-off shaft of the electric motor, in which the electric motor comprises a stator and a rotor comprising the power take-off shaft, is characterized in that the speed-transforming transmission is arranged inside the power take-off shaft constituted as a hollow shaft.

Claims

1. A drive unit with an electric motor and a speed-transforming transmission connected in a rotationally driven manner to a power take-off shaft of the electric motor, wherein the electric motor comprises a stator and a rotor comprising the power take-off shaft, characterized in that the speed-transforming transmission is arranged inside the power take-off shaft constituted as a hollow shaft; wherein the speed-transforming transmission is arranged inside a transmission housing of a transmission unit; characterized by a drive housing retaining the electric motor and the speed-transforming transmission.

2. The drive unit according to claim 1, characterized in that the electric motor is constituted as a servomotor.

3. The drive unit according to claim 1, characterized in that the speed-transforming, transmission forms a planetary gear.

4. The drive unit according to claim 3, characterized in that the stator of the electric motor is connected in a rotationally rigid manner to the static part of the unit to be driven.

5. The drive unit according to claim 3, wherein the drive housing is connected in a rotationally rigid manner to the static part of the unit to be driven.

6. The drive unit according to claim 1, characterized in that the power take-off shaft extends at least at one longitudinal-axial end beyond the stator with a bearing portion and is mounted in this bearing portion in a rotatable manner within the drive housing.

7. The drive unit according to claim 1, further comprises a unit to be driven, which comprises a static part and a rotatable part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail on the basis of an exemplary embodiment presented in the drawings. The drawings show:

(2) FIG. 1: in a simplified view, a combination according to the invention of a drive unit according to the invention and a unit to be driven.

DETAILED DESCRIPTION OF THE INVENTION

(3) The drive unit of the combination according to the invention illustrated in FIG. 1 comprises a drive housing 1, which constitutes a retaining recess 2 open towards a front end, which is provided for the largely complete accommodation of both an electric motor and also a transmission unit 3 of the drive unit.

(4) The electric motor is constituted as a servomotor and comprises a stator 4 which can be connected in a rotationally rigid manner, for example, via one or more screw connections or threaded connections to the drive housing 1, and a rotor 5 arranged in a rotatable manner inside the stator 4, which comprises a power take-off shaft 6 which is constituted in one portion as a hollow shaft. The internal volume 7 of this portion of the power take-off shaft 6 extends, here, up to the front end of the power take-off shaft 6 at which the drive housing 1 is also constituted to be open. At the other end of the power take-off shaft 6, the latter projects with a bearing portion beyond the stator 4 of the electric motor and into a first portion of the retaining recess 2 of the drive housing 1, which comprises a smaller diameter by comparison with a second portion, inside of which, inter alia, the stator 4 of the electric motor is arranged. In this first portion of the retaining recess 2, the corresponding bearing portion of the power take-off shaft 6 is mounted in a rotatable manner via a rotary bearing 8.

(5) A power take-off journal 9 projecting centrally from the base of the internal volume 7 of the output shaft serves for a rotationally rigid connection with an input shaft 10 of the transmission unit 3, which is arranged completely inside the power take-off shaft 6 of the electric motor, with the exception of one portion of an output shaft 11 of the transmission unit 3. In the present exemplary embodiment, the transmission unit 3 is constituted as a planetary gear unit 3.

(6) The transmission unit 3 comprises a transmission housing 12, inside of which transmission components (partially not illustrated) of a single or multiple planetary gear and accordingly, inter alia, one or more rotating wheels and one or more orbited wheels are arranged in encapsulated embodiment. In this context, an embodiment of the planetary gear with one or more combinations of sun wheel, planetary wheel or wheels, and hollow wheel can be advantageous with regard to a desired compact overall size and especially overall length. In particular, the wheels of the planetary gear can, cooperate in a form-fit manner and can especially be constituted as cog wheels. The transmission housing 12 can therefore itself constitute a transmission component and, for example, serve as a hollow wheel for the planetary gear.

(7) The portion of the output shaft 11 of the transmission unit 3 projecting from the power take-off shaft 6 of the electric motor and also from the drive housing 1 serves for a rotationally rigid connection with a rotatable part 13 of the unit to be driven, illustrated in an extremely simplified manner, which comprises another static part 14 alongside this rotatable part 13. The unit to be driven can be, for example, a tool unit, in which the tool to be driven represents the part to be driven or is connected to the latter in a rotationally driven manner. The static part 14 in such a tool unit can be constituted, in particular, by a tool housing, which can serve primarily for an at least rotatable bearing of the tool.

(8) In order to support the rotary moment generated by the electric motor and to guarantee the desired speed-transformation by the transmission unit 3, it can be provided that both the drive housing 1 and also the transmission housing 12 are connected in a rotationally rigid manner to the static part 14 of the unit to be driven. For example, screw

LIST OF REFERENCE NUMBERS

(9) 1 Drive housing

(10) 2 Retaining recess

(11) 3 Transmission unit

(12) 4 Stator

(13) 5 Rotor

(14) 6 Power take-off shaft

(15) 7 Internal volume of the power take-off shaft

(16) 8 Rotary bearing

(17) 9 Power take-off journal

(18) 10 Input shaft of the transmission unit

(19) 11 Output shaft of the transmission unit

(20) 12 Transmission housing

(21) 13 Rotatable part of the unit to be driven

(22) 14 Static part of the unit to be driven

(23) 15 Screw connection