Fan having an external rotor motor and cooling duct for cooling the motor electronics and motor drive components

Abstract

A fan has an external rotor motor with a motor section and an electronics section. The motor section and the electronics section are arranged axially adjacent to each other along the axis of rotation. The fan, when operated as intended, generates, via the fan wheel, a pressure difference between its suction side, which is preferably associated with the rotor, and its pressure side, which is preferably associated with the motor electronics. A continuous cooling duct runs within the external rotor motor from a pressure-side inflow opening, at least along sections of the rotor, to a suction-side outflow opening. An exclusively passive cooling air flow through the cooling duct can be generated in operation by the pressure difference generated by the fan wheel.

Claims

1. A fan having an external rotor motor comprising: a rotor rotating about an axis of rotation in a motor section and configured to receive a fan wheel in an outwardly enclosing manner; motor electronics are arranged in an electronic section and housed in an electronics housing, the motor section and the electronics section are arranged axially or radially adjacent to each other along the axis of rotation; the fan generates a pressure difference (Δp) between its suction side and its pressure side by the fan wheel such that an air flow generated by the fan wheel flows in a first direction; a continuous cooling duct runs inside the external rotor motor from a flow opening at the electronics housing along the motor electronics and at least along sections of the rotor to a flow opening in the motor section and an exclusively passive cooling air flow flowing in a second direction opposite to the first direction, through the cooling duct, can be generated in operation due to the pressure difference (Δp) generated by the fan wheel to cool both the electronics section and the motor section so that a negative pressure p− is used to generate a suctioning of a cooling air flow, in the second direction, that runs as a compensation flow against the first flow direction of the air flow generated by the fan wheel.

2. The fan according to claim 1, wherein the flow opening at the electronics housing defines a pressure-side inflow opening and the flow opening in the motor section defines a suction-side outflow opening.

3. The fan according to claim 2, wherein multiple cooling fins are formed on the electronics housing that extend axially and radially into the cooling duct starting from the inflow opening and form a duct wall surface of the cooling duct.

4. The fan according to claim 2, wherein the rotor comprises a rotor housing and the outflow opening is formed in a region of an axial end face of the rotor housing.

5. The fan according to claim 2, wherein the fan wheel comprises an impeller base plate with impeller blades wherein the base plate forms the outflow opening.

6. The fan according to claim 5, wherein the external rotor motor has, in the motor section, a stator bushing with a stator pack and motor windings as well as stator cooling fins which are distributed in a peripheral direction, the cooling duct runs along the stator cooling fins.

7. The fan according to claim 6, wherein the impeller base plate axially runs adjacent to the stator cooling fins that extend axially to the impeller base plate, such that the cooling air flow can be conducted axially via the stator cooling fins to the outflow opening in the impeller base plate.

8. The fan according to claim 1, wherein the external rotor motor has, in the motor section, a stator bushing with a stator pack and motor windings as well as stator cooling fins that are distributed in a peripheral direction, the cooling duct runs along the stator cooling fins and along the stator pack.

9. The fan according to claim 1, wherein the cooling duct is substantially closed at a transition from the electronics section to the motor section by a standing or rotatable unbladed cover.

10. The fan according to claim 1, wherein the cooling duct has multiple changes of direction in its course from the inflow opening to the outflow opening, such that the cooling air flow is diverted multiple times.

11. The fan according to claim 1, wherein the outflow opening is at an axial spacing from the fan wheel at the rotor.

12. The fan according to claim 1, wherein the cooling duct runs in a peripheral direction, locally limited to the electronics section and the motor section.

13. The fan according to claim 1, wherein the rotor is supported by at least one bearing and the cooling duct leads past the at least one bearing.

14. The fan according to claim 1, wherein the rotor is associated with the suction side and the motor electronics is associated with the pressure side.

15. A fan having an external rotor motor comprising: a rotor rotating about an axis of rotation in a motor section and configured to receive a fan wheel in a radially outward enclosing manner; motor electronics are arranged in an electronics section, the motor section and the electronics section are arranged axially or radially adjacent to each other along the axis of rotation; the external rotor motor in the motor section comprises a stator bushing with a stator pack and motor windings as well as stator cooling fins which are distributed in a peripheral direction; the fan, when operated as intended, generates a pressure difference between its suction side, on a first side of a housing, and its pressure side, on a second opposite side, of the housing, by the fan wheel such that an air flow generated by the fan wheel flows in a first direction from the suction side to the pressure side of the housing; a continuous cooling duct runs inside the external rotor motor along the stator cooling fins from a pressure-side inflow opening, on the second opposite side, to a suction-side outflow opening, on the first side, and an exclusively passive cooling air flow flowing in a second direction opposite to the first direction, through the cooling duct, can be generated in operation due to the pressure difference generated by the fan wheel so that a negative pressure p− is used to generate a suctioning of a cooling airflow, in the second direction, that runs as a compensation flow against the first flow direction of the air flow generated by the fan wheel, at least one power module of the motor electronics is directly arranged next to the stator bushing which has the stator cooling fins to cool the motor section and at least the power module of the motor electronics by means of the stator bushing.

Description

DRAWINGS

(1) Embodiment examples of the disclosure are described below in reference to the drawings. The disclosure is not limited to these embodiment examples. The drawings, in reference to figures, shows the basic design of the present, namely:

(2) FIG. 1 is a schematic view illustrating the pressure difference generated by the fan.

(3) FIG. 2 is a perspective partially cross-section view of an exemplary embodiment of the external rotor motor designed for an axial, radial, or diagonal fan.

(4) FIG. 3 is an elevation partially in cross-section view of an exemplary embodiment of the fan in an axial fan design.

(5) FIG. 4 is an elevation partially in cross-section of an exemplary embodiment of the fan in a radial fan design.

(6) FIG. 5 is an elevation partially in cross-section of an alternative exemplary embodiment of the fan in a first variant.

(7) FIG. 6 is an elevation partially in cross-section view of an exemplary embodiment of another variant of the fan from FIG. 5.

DETAILED DESCRIPTION

(8) The figures are schematic for illustration. Like reference numbers in the figures indicate like functional and/or structural features.

(9) FIG. 1 schematically shows an example of the pressure difference Δp generated in operation by a fan wheel 25 of the fan 1 and the intake-side negative pressure p− and the pressure side, that is, outflow-side positive pressure p+. In this case, the negative pressure p− is used to generate a suctioning of a cooling air flow that runs as a compensation flow against the main flow direction of the air flow generated by the fan wheel 25.

(10) FIG. 2 shows a first exemplary embodiment of a partially cut-open external rotor motor 20 of the fan 1, designed as an axial fan. The overall arrangement of the external rotor motor 20 is axially divided into the electronics section 21 and the directly axially adjacent motor section 22. The motor electronics 11 is received in the lid-shaped electronics housing 12 in the electronics section 21. The motor drive components responsible for driving the fan wheel 25 (not shown here, but placed onto the rotor 2 in a manner shown in FIG. 3), particularly the cylindrical rotor 2 with its cup-shaped rotor housing 13 (rotor bell) and the stator pack 8 with motor windings received therein are accommodated in the motor section 22. The bearing 14 of the motor shaft is also visible.

(11) The inflow opening 71 for the cooling air flow 7 is provided on the end face of the electronics housing 12. Axially and radially extending cooling fins 3 are provided starting from the inflow opening and define sections of duct wall surfaces of the cooling duct 10. The cooling duct 10 is continuous and runs in the radially outer portion of the external rotor motor. The cooling duct 10 is diverted radially outwards following the inflow opening 71 and past electronics components arranged on a circuit board 15 which define the motor electronics 11, then again diverted radially inwards to the rotor 2. In the region of the rotor 2, the cooling duct 10 runs axially straight inside the rotor housing 13 directly along the stator pack 8 and the bearing 14 to the outflow opening 72 on the axial end face. In the region of the rotor 2, the cooling duct is not specifically walled in the embodiment shown. Thus, the cooling air flow can freely flow along the path of lowest resistance along the motor components to the outflow opening 72. Alternatively, however, a cooling duct can be provided with a special guidance along specific components, that is formed as a closed duct by defined boundaries, for example the inner wall surface of the rotor housing.

(12) In the region adjacent to the electronics section 21, stator cooling fins 5 distributed in the peripheral direction extend towards the rotor 2 in the motor section 22. The cooling duct 10 runs past the stator cooling fins 5. Thus, the cooling air flow 7 dissipates the heat absorbed by the stator cooling fins 5. The transition to the rotor 2 is closed by the cover 6. It is fastened to the electronics housing 12 and has a labyrinth shape to minimize pressure loss. Sections of the cover 6 form both a duct wall surface of the cooling duct 10 and an outer shell surface of the external rotor motor 20. When in operation, the cooling air flow 7 is suctioned in at the suction-side outflow opening 72 in the motor section 22, such that it flows into the inflow opening 71 on the pressure side and through the overall arrangement of the external rotor motor 20 to the outflow opening 72. Since the cooling air flow 7 is exclusively generated by the pressure difference between the suction side and the pressure side, it is in this case called passive.

(13) FIG. 3 shows a side view of an exemplary embodiment of the fan 1 in an alternative design as an axial fan. The features described for the external rotor 20 from FIG. 1 are present here as well, unless explained otherwise. The fan wheel 25 is fastened to the rotor 2 such that its impeller hub completely encloses the rotor housing 13. In operation, the fan wheel 25 generates the main flow and also the pressure difference Δp used for the cooling air flow 7. In this embodiment, the outflow opening 72 is not provided at the rotor housing 13, but at the fan wheel 25 or its impeller hub, respectively. The cooling air flow 7 in the motor section 22 runs radially between the rotor housing 13 and the impeller hub 17 of the fan wheel 25. Thus, the cooling duct 10 is formed in the motor section 22 by the rotor housing 13 and the impeller hub of the fan wheel 25.

(14) FIG. 4 shows an exemplary embodiment of the fan 1 in a design as a radial fan. The cooling duct 10, unlike in the preceding examples, is not conducted along the entire rotor 2. The fan wheel 25 of the radial fan has an outflow opening 72 in its impeller base plate 26. The impeller base plate 26 carries the impeller blades 9, which in the present embodiment are bent rearwards. The cooling duct 10 thus runs from the inflow opening 71 in the electronics housing 12 along the cooling fins 3 to the motor section 22 and therein along the stator cooling fins 5 radially outwards to the outflow opening 72 at the impeller base plate 26. The cooling air flow 7 is moved away to radially outwards by the fan wheel 25. The cooling in the electronics section 21 is identical with the preceding exemplary embodiments. Cooling in the motor section 22 is mainly performed via the stator cooling fins 5.

(15) FIG. 5 shows an alternative embodiment of the fan 1 in a design as a radial fan with the external rotor motor 20. Like the preceding exemplary embodiments, the motor section 22 and the electronics section 21 are axially adjacent along the axis of rotation RA with the motor electronics 11 arranged therein. All features identical with the preceding embodiments are not repeated, but they also apply to the exemplary embodiment according to FIG. 5. In an alternative embodiment not shown, the electronics section can also be oriented radially to the axis of rotation RA. The fan wheel 25 is received at the rotor 2 on the radial outside. The fan 1 generates a pressure difference Δp between its suction side and its pressure side by the fan wheel 25. Within the external rotor motor 20, the continuous cooling duct 10 runs from the pressure-side inflow opening 71 to the suction-side outflow opening 72 along the stator cooling fins 5. The cooling air flow 7 through the cooling duct 10, represented by arrows, is generated in operation exclusively passively by the pressure difference Δp generated by the fan wheel 25.

(16) The power module 47 of the motor electronics 11 generates the most heat and is therefore directly arranged next to the stator bushing 29 which has the stator cooling fins 5 to cool the motor section 22 and the power module 47 of the motor electronics 11 by the stator bushing 29.

(17) FIG. 6 shows another exemplary embodiment of the fan 1, the structure of which is identical with that of FIG. 5, except for the following differences. The cooling air flow 7 remains outside the rotor 2 as in the embodiment according to FIG. 4. In this embodiment as well, the fan wheel 25 of the fan has the outflow opening 72 in the impeller base plate 26 that carries the rearward-bent impeller blades 9. The cooling duct 10 runs radially outside along the stator cooling fins 5 to the outflow opening 72 at the impeller base plate 26. The cooling air flow 7 is moved radially outwards by the fan wheel 25. Like in the embodiment according to FIG. 5, the fan 1 generates a pressure difference Δp between its suction side and its pressure side by the fan wheel 25. In operation, an exclusively passive cooling air flow 7, through the cooling duct 10, can be generated by the pressure difference Δp generated by the fan wheel 25. The power module 47 of the motor electronics 11 is also, in this embodiment, directly arranged next to the stator bushing 29 that has the stator cooling fins 5 to cool the motor section 22 and the power module 47 of the motor electronics 11 directly by the stator bushing 29. In the fan 1 according to FIG. 6, the electronics section can also be oriented or positioned radially rather than axially to the axis of rotation RA.

(18) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.