Patent Application
20250030304
This application claims priority to DE 10 2023 119 360.0, filed Jul. 21, 2023, the entire disclosure of which is hereby incorporated herein by reference.
This disclosure relates to an external rotor motor with an internally cooled stator, and is based on an electric motor of the type generally known, for example, from EP 3 091 638 B1.
External rotor motors with an internally cooled stator, that is to say, a cooling channel that runs through an internal space surrounded by the stator, enable a high performance in combination with a compact design.
This disclosure demonstrates a way in which an electric motor of the aforementioned type can be produced with less effort.
In an electric motor in accordance with this disclosure, an insert is arranged in an interior space surrounded by the stator, which insert, together with an inner part of a housing component, defines at least one section of a cooling channel. An insert, which has recesses on its exterior surface to form sections of a cooling channel, and is then inserted into a suitable opening in a housing component, can be produced cost-effectively. In particular, the cost is lower than that of the creation of channels inside a housing component, for example, using a lost mold casting process. Moreover, the insert can be produced from a material that differs from that of the housing component, for example, from a plastic.
The housing component, which together with the insert defines sections of the cooling channel, has an inner part that protrudes into the stator, for example, into a central opening of an annular stack of stator laminations. This inner part, in turn, has an opening into which the insert is inserted. The housing component therefore bounds the cooling channel in the interior space surrounded by the stator on the radially outer face. The cooling channel can be bounded radially inwards and laterally by the insert.
An advantageous refinement of this disclosure provides that the insert is positioned in the housing component by means of a tongue-and-groove joint. In this way, the insert can be positioned in its rotational angle position relative to the housing component with little effort. The tongue of the said tongue-and-groove joint can be formed on the housing component or the insert. However, in general terms it is better to provide the tongue of the said tongue-and-groove joint on the housing, since the thickness of the wall in contact with the stator can then be reduced, and thus a better thermal coupling of the cooling channel with the stator can be achieved. The groove of the tongue-and-groove joint can extend over the entire axial length of the insert. In many cases, however, a short groove at one axial end of the insert is sufficient.
Another advantageous refinement of this disclosure envisages that the insert surrounds an annular space, in which one end of the shaft is arranged. Advantageously, the cooling channel thus defined by the insert and housing component can also be used to cool a bearing of the shaft arranged in the annular space.
Another advantageous refinement of this disclosure provides that the insert has a rib running in the axial direction, along which runs the cooling channel. In this way, the mechanical stability of the insert can advantageously be increased.
Another advantageous refinement of this disclosure provides that the insert is covered by a cooling plate, along the lower face of which runs the cooling channel, and against the upper face of which abuts an electronic component of the control electronics. In this way, the cooling channel can advantageously also be used to cool one or more electronic components, such as power transistors, with which the power supply of stator windings is switched. Such a cooling plate can have protuberances on its lower face that protrude into the cooling channel. The cooling channel can run along the lower face of the cooling plate in the direction of flow, before it leads into the interior space surrounded by the stator, or vice versa, that is to say, a cooling channel section on the lower face of the cooling plate is located downstream of a cooling channel section in the interior space surrounded by the stator.
The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:
The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.
The electric motor shown in
Together with a third housing component 8, the first housing component 6 defines an electronics compartment, in which is arranged a circuit board 9 with control electronics. The motor compartment and the electronics compartment are separated from each other by a wall 10 of the first housing component 6. The printed circuit board 9 faces the said wall 10, that is to say, is orientated essentially at right angles to the longitudinal axis of the shaft 5. The motor compartment and the electronics compartment are sealed from each other. Electrical cables, which connect the stator windings 2 to the printed circuit board 9 of the control electronics, are routed through sealed openings in the wall 10 of the first housing component 6.
The first housing component 6 has an inlet 11 and an outlet 12 for coolant. A cooling channel, which leads from the inlet 11 to the outlet 12, has a channel section 15 for purposes of cooling an electronic component 17 of the control electronics, and a channel section 16 for purposes of cooling the stator 1. The channel sections 15, 16 are connected in series. In the example of embodiment shown, the cooling channel section 15 for purposes of cooling the electronic component 17 is arranged upstream of the channel section 16 for purposes of cooling the stator 1. However, it is also possible for the flow to pass through the cooling channel section 15 only after the flow passes through the cooling channel section 16.
The cooling channel section 16 for purposes of cooling the stator 1 runs in an interior space surrounded by the stator 1. This cooling channel section 16 is therefore also bounded by the wall 10, which separates the motor compartment from the electronics compartment. In the example of embodiment shown, the wall 10 forms an annular space surrounded by the stator 1, into which an insert 20 is inserted, which, together with the wall 10, defines the cooling channel section 16.
The first housing component 6 carries a cooling plate 18, along the lower face of which coolant flows when in operation. For example, the cooling plate 18 together with the wall 10, which separates the engine compartment from the electronics compartment, can define a start and an end section of the cooling channel, in particular also the cooling channel section 15 for purposes of cooling the electronic component 17 of the control electronics. One or a plurality of electronic components 17 of the control electronics abut against the upper face of the cooling plate 18. To improve heat dissipation, the cooling plate 18 can have protuberances 19 on its lower face, which protrude into the cooling channel section 15.
The insert 20 can be positioned in the first housing component 6 by means of a tongue-and-groove joint, for example. The insert 20 has a rib 23 running in the axial direction, along which rib the cooling channel leads. This axial rib 23 has the effect of stiffening the insert, and extends over the entire axial length of the insert 20.
In the example of embodiment shown, the insert 20 has a plurality of ribs 24 running in the circumferential direction, along which ribs the cooling channel leads. Between these ribs 24, which are arranged parallel to one another, cooling channel sections run in the circumferential direction, which sections are arranged one behind the other in the direction of flow. The cooling channel therefore extends without branches in the interior space.
The insert 20 shown in
While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 119 360.0 | Jul 2023 | DE | national |
