Reel motor with closed cooling circuit

1. A reel motor for a driven conveyor roller comprising:

a stator surrounded by a stator housing and a rotor driving a rotor shaft;

a tubular external housing runs around the stator housing at a distance in the circumferential direction;

a cooling duct, is fluidically connected to an interior of the stator housing holding the stator, the cooling duct is formed between the external housing and the stator housing; and

an impeller wheel is secured to the rotor shaft, the impeller wheel generates a cooling air flow, the interior of the stator housing and the cooling duct determine a closed cooling circuit through which the cooling air flow is guided.

2. The reel motor according to claim 1 , wherein

the stator housing, along its axial longitudinal direction, has two external sections and, lying axially in between, a directly adjoining middle section,

the stator and the rotor are arranged in the middle section, and,

in the external sections of the stator housing, respective openings leading to the cooling duct are provided for the fluidic connection.

3. The reel motor according to claim 2 , wherein

the openings extend in the radial direction.

4. The reel motor according to claim 2 , wherein

the impeller wheel is provided on the rotor shaft in an area facing the openings and is designed to conveys air through the openings from the stator housing into the cooling duct or from the cooling duct into the stator housing.

5. The reel motor according to claim 1 , wherein

the external housing is sealed off with respect to the environment by at least one sealing element.

6. The reel motor according to claim 1 , wherein

the stator housing is secured on an axle extending axially out of the external housing and arranged concentrically with respect to the rotor shaft, and the external housing is rotatably mounted with respect to the axle.

7. The reel motor according to claim 1 , wherein

the external housing is connected to the rotor shaft.

8. The reel motor according to claim 7 , further comprising a gearbox,

the external housing is connected via the gearbox to the rotor shaft.

9. The reel motor according to claim 8 , wherein,

when viewed in the axial direction, the impeller wheel is arranged between the stator and the gearbox.

10. The reel motor according to claim 1 , wherein

the stator comprises stator windings that are arranged in the interior of the stator housing, so that the cooling air flow runs through along the stator windings and/or between the stator windings.

11. The reel motor according to claim 1 , wherein

the rotor shaft is mounted in the stator housing rotatably with respect to the stator housing via a bearing plate and a bearing accommodated in the bearing plate, and the bearing plate has flow passages which determine a portion of the closed cooling circuit.

12. The reel motor according to claim 11 wherein

the flow passages of the bearing plate are oriented facing the stator and/or designed in the form of nozzles.

13. The reel motor according to claim 1 , wherein

the external housing has cooling ribs on its internal wall side facing the stator housing or the stator housing has cooling ribs on its external wall side facing the external housing.

14. The reel motor according to claim 1 , wherein

the external housing has guide elements guiding the cooling air flow on its internal wall side facing the stator housing or the stator housing has guide elements on its external wall side facing the external housing.

15. A conveyor roller with a reel motor according to claim 1 , with a cylindrical roller body, wherein the roller body is formed by the external housing of the reel motor.