DE102022001408A1 - axial flow machine - Google Patents

Abstract

The invention relates to an axial flux machine with a stator (1), which has a stator housing (8) and arranged therein a plurality of windings designed as individual teeth (2), each comprising a laminated core wrapped with copper wire, and between which there are radially running spaces (3) are provided, with the stator housing (8) having an outer collecting space (4) radially outside the individual teeth (2), an inner collecting space (5) radially inside the individual teeth (2), an inlet (10) and a return (11 ) are arranged, the stator (1) being configured to flow through the inlet (10) into one of the plenums (4, 5), through the interspaces (3) into the other of the plenums (4, 5) and through the return (11) to be flowed through by a cooling fluid (KF), a valve device (6) acting on the flow of the cooling fluid (KF) being provided, the valve device (6) having a plurality of valve vanes (7) or flaps, which one ferromagnetic en material are formed or have such, and are configured to change their shape and / or position under the influence of a stator (1) emanating magnetic field as a result of a current flow so that a flow cross-section for the cooling fluid (KF) in the stator ( 1) is changed in such a way that cooling fluid (KF) does not flow through the stator (1) in the de-energized state, at least to a large extent, and that the flow of cooling fluid (KF) increases with increasing current flow.

Description

The invention relates to an axial flow machine according to the preamble of claim 1, in particular for use as a drive machine in a motor vehicle.

The stator, in particular the stator winding, of an electrical axial flow machine must be actively cooled with a cooling fluid during operation, depending on the operating state of the machine. In order to keep the electrical or mechanical power requirement of a cooling fluid delivery as low as possible, the components to be cooled should only be supplied with cooling fluid when required.

The cooling fluid flow can be controlled, for example, via electrically switched valves. Disadvantages here are the installation space to be provided and the required electrical control and the costs of separate fluid valves.

EP 2 606 561 B1 describes an electric machine comprising a rotor with permanent magnets and a stator with coils wound on stator bars for cooperating with the magnets across an air gap defined between them. The bars and coils are enclosed in an annular stator housing that extends between the air gaps. The stator housing includes two mating shells that hold the stator bars and coils in the machine. Each shell is injection molded from reinforced plastic and at least one shell has stator bar shoes molded therein forming part of the radial wall and optionally one or more of the following: cylindrical hub supports extending along the outer cylindrical wall; connector pins electrically connecting the chamber to the outside; stator coils; coolant inlet and outlet ports for supplying/removing coil coolant to/from the housing; and an outer ring of a rotor bearing. The clamshell has a reduced thickness and molding material flow grooves may be formed on the interface of the pole piece.

The invention is based on the object of specifying a novel axial flow machine.

The object is achieved according to the invention by an axial flow machine with the features of claim 1.

Advantageous configurations of the invention are the subject matter of the dependent claims.

An axial flux machine according to the invention comprises a stator and a rotor, the stator having a stator housing and arranged therein a plurality of windings designed as individual teeth, each comprising a laminated core wrapped with copper wire, and between which radially running spaces are provided, with the stator housing an outer plenum radially outside of the discrete teeth, an inner plenum radially inward of the discrete teeth, an inlet and a return, the stator being configured to flow through the inlet into one of the plenums, through the spaces in the other of the plenums and through the Return to be flowed through by a cooling fluid, wherein a valve means acting on the flow of the cooling fluid is provided. According to the invention, the valve device has a plurality of valve vanes or flaps which are formed from a ferromagnetic material or have such a material and which are configured to change their shape and/or position under the influence of a magnetic field emanating from the stator as a result of a current flow in such a way that that a flow cross-section for the cooling fluid in the stator is changed in such a way that cooling fluid does not flow through the stator in the current-free state, at least to a large extent, and that the flow of cooling fluid increases with increasing current flow.

The present invention enables the flow of cooling fluid through the stator of the axial flow machine to be controlled by the stator magnetic field that exists during operation.

The need-based supply of cooling fluid to the stator can thus be implemented without valves that have to be kept available and controlled separately in the environment of the electrical machine. As a result, an electrohydraulic control unit of the electric drive can be simplified.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

• 1 eine schematische Ansicht eines Stators einer Axialflussmaschine mit Ventilflügeln in einem geschlossenen Zustand, und
• 2 eine schematische Ansicht des Stators, wobei die Ventilflügel unter Einfluss eines vom Stator ausgehenden Magnetfelds infolge eines Stromflusses geöffnet sind.

show:

• 1 a schematic view of a stator of an axial flow machine with valve vanes in a closed state, and
• 2 a schematic view of the stator, wherein the valve vanes are opened under the influence of a magnetic field emanating from the stator as a result of a current flow.

Corresponding parts are provided with the same reference symbols in all figures.

The present invention relates to an electric machine, for example for driving a predominantly or exclusively electrically driven vehicle. The electrical machine is, for example, an axial flow machine with a stator through which oil or coolant flows. The stator through which oil or coolant flows should be supplied with cooling fluid as required and/or the cooling fluid supply should be blocked when the stator is not energized.

1 12 is a schematic view of a stator 1 of an axial flux machine. The stator 1, in particular the stator winding, of an electrical machine, in particular an axial flow machine, must be actively cooled with a cooling fluid KF during operation, depending on the operating state of the machine. The cooling fluid KF partially flows around the windings of the stator 1 which are designed as individual teeth 2 and are arranged in a stator housing 8 . These individual teeth 2 are to be understood in each case as a partial component of the stator 1 which comprises a suitably shaped laminated core wrapped with copper wire and possibly an additional plastic sheathing. These individual teeth 2 are in the stator 1 as in EP 2 606 561 B1 or GB 2 482 928 A arranged as described. EP 2 606 561 B1 and GB 2 482 928 A are hereby fully incorporated by reference into the present patent application.

The cooling fluid KF is routed around the individual teeth 2 in a suitable manner. Due to the principle, radially running gaps 3 between the individual teeth 2 are used for this in relation to an axis of rotation of the axial flux machine, since an air gap between the stator 1 and a rotor disk of the axial flux machine should be kept as small as possible in the axial direction in order to limit electromagnetic losses.

As it flows through the stator 1, the cooling fluid KF passes through an outer collecting space 4 radially outside the individual teeth 2, gaps or spaces 3 between the individual teeth 2 serving as a cooling channel, and an inner collecting space 5 radially inside the individual teeth 2. The collecting spaces 4, 5 and the individual Intermediate spaces 3 can be traversed hydraulically in different sequences.

In order to keep the electrical or mechanical power requirement for conveying the cooling fluid KF as low as possible, the components to be cooled should only be supplied with cooling fluid KF when required.

The present invention uses a magnetic field of the stator windings, which is produced by current flow when the axial flow machine delivers torque, to actuate a valve device 6 that acts on the flow of cooling fluid KF.

The valve device 6 is designed in such a way that cooling fluid KF does not flow through the stator 1 in the de-energized state of the axial flow machine. With increasing current flow through the stator windings, the current of the cooling fluid KF should increase since the heat input into the stator 1 is essentially proportional to the current flow through the stator windings.

For this purpose, the valve device 6 has valve vanes 7 or flaps made of completely or at least partially ferromagnetic material, which change their shape and/or position under the influence of the magnetic field emanating from the stator 1 in such a way that a flow cross section for the cooling fluid KF is released in the stator 1 or in its size is changed to an appropriate extent.

In 1 the valve vanes 7 are shown in the closed state. The cooling fluid KF does not flow through the stator 1 .

2 is a schematic view of the stator 1 of the axial flow machine, the valve vanes 7 being open under the influence of the magnetic field emanating from the stator 1 as a result of a current flow. A partial flow is therefore branched off from a main fluid flow 9 flowing around the stator housing 8 through an inlet 10, which passes through the stator 1, i.e. the outer collecting space 4, the intermediate spaces 3 and the inner collecting space 5, and is discharged from the stator 1 through a return 11 .

The valve wings 7 are mounted in particular fixed to the housing. When there is no current in the stator winding, the flow cross section available to the cooling fluid KF through the valve vanes 7 should be smaller than in the current-carrying state. Ideally, the flow cross-section can be zero when there is no current in the stator winding.

When the stator winding is energized, the flow cross-section available for the cooling fluid KF should be larger than in the de-energized state. During the transition from the energized to the de-energized state, the valve vanes 7 should automatically move back into an initial position and reduce the flow cross section. This can be achieved by an elastic design of the valve wing 7 itself, a corresponding springing and/or an alignment against a direction of flow.

The geometry of the valve vane 7 can be chosen so that the flow cross section proportional to the heat input caused by the current flow.

In the embodiment shown, the valve vanes 7 are attached in pairs, each with a fixed end, to a fixed point 12 on the stator housing 8 in the area of the outer collecting space 4 . A free end of each valve vane 7 points in the direction of an adjacent pair of valve vanes 7 and, together with the free end of one of the valve vanes 7 of the adjacent pair, determines the cross section of one of the intermediate spaces 3. In the initial position, the free ends of these valve vanes 7 can, for example, abut one another or almost touching each other.

Reference List

1

stator

2

single tooth

3

space

4

outer plenum

5

inner gathering space

6

valve device

7

valve vane

8th

stator housing

9

main fluid stream

10

Intake

11

return

12

fixed point

KF

cooling fluid

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2606561 B1 [0004, 0015]
• GB 2482928A [0015]

Claims (7)

Axial flow machine with a stator (1) and a rotor, the stator (1) having a stator housing (8) and arranged therein a plurality of windings designed as individual teeth (2), each comprising a laminated core wrapped with copper wire, and between them radially running intermediate spaces (3) are provided, with an outer collecting space (4) radially outside the individual teeth (2), an inner collecting space (5) radially inside the individual teeth (2), an inlet (10) and a return (11) are arranged, the stator (1) being configured to flow through the inlet (10) into one of the collecting spaces (4, 5), through the intermediate spaces (3) into the other of the collecting spaces (4, 5) and to be flowed through by a cooling fluid (KF) through the return (11), a valve device (6) acting on the flow of the cooling fluid (KF) being provided, characterized in that the valve device (6) has a plurality of valve vanes (7 ) or flaps, which are formed from a ferromagnetic material or have such a material and which are configured to change their shape and/or position under the influence of a magnetic field emanating from the stator (1) as a result of a current flow such that a flow cross section for the cooling fluid (KF) in the stator (1) is changed in such a way that cooling fluid (KF) does not flow through the stator (1) in the current-free state, at least to a large extent, and that the flow of cooling fluid (KF) increases with increasing current flow. axial flow machine claim 1 , characterized in that the flow cross section is zero in the de-energized state. axial flow machine claim 1 or 2 , characterized in that the valve vanes (7) are elastic and / or provided with a spring and / or have an orientation against a flow direction to move back to a starting position in the de-energized state and to reduce the flow cross section. Axial flow machine according to one of the preceding claims, characterized in that the geometry of the valve vanes (7) is selected in such a way that the flow cross section changes proportionally to a heat input caused by the current flow. Axial flow machine according to one of the preceding claims, characterized in that the valve vanes (7) are attached in pairs, each with a fixed end, to a fixed point (12) on the stator housing (8) in the area of the outer collecting chamber (4), with a free end of each valve vane (7) together with a free end of one of the valve vanes (7) of an adjacent pair determines the cross-section of one of the intermediate spaces (3). Axial flow machine according to one of the preceding claims, characterized in that the individual teeth (2) each have a plastic coating. Use of an axial flow machine according to one of the preceding claims for driving a predominantly or exclusively electrically driven vehicle.

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