Connection plate for electrically and fluidly connecting hollow conductors of an internally cooled electric machine and an electric machine equipped with a connection plate of this type - Patent 7326333

Abstract

The invention relates to an electric machine (1) with windings formed from hollow conductors (5), each having an open end (12) through which a coolant can be supplied to or flow out of the hollow conductors (5). The electric machine (1) comprises a connection unit (3) for electrically and fluidly connecting the hollow conductors (5), having a connection plate (6) incorporating a number of electrical conductor paths (11), the connection plate (6) having a number of through openings (15) in which the ends (12) of the hollow conductors (5) are arranged.

Description

[Technical field]

[0001] The present invention relates to an internally cooled electric machine comprising a hollow conductor winding and a connection plate for electrically and hydraulically connecting the hollow conductor. [Background technology]

[0002] From the prior art, internally cooled electric machines are known which have hollow conductor windings having channels passing therethrough through which a coolant is piped in order to cool the electric machine during operation.

[0003] The hollow conductors known from the prior art usually have the form of hairpins or pins. The pins or hairpins are rigid windings, mainly made of copper, that are placed in grooves in the stator of the electric machine and generate the necessary magnetic field during operation of the electric machine. Another embodiment of an internally cooled electric machine includes windings made of thin hollow conductors wound into coils.

[0004] The hollow conductor has an open end through which coolant can be supplied to or flow out of the hollow conductor. Known hollow conductors are usually provided with an electrically insulating layer on their surface.

[0005] DE 10 2018 218 668 A1 discloses an electric machine with windings formed from hollow conductors and a connection unit for electrically and fluidly connecting the hollow conductors, each having an open end via which a coolant can be supplied to the hollow conductors or can flow out of the hollow conductors, the connection unit comprising a connection plate in which a number of electrical conductor paths are integrated, the connection plate having a number of through openings in which the ends of the hollow conductors are arranged. Another electric machine with hollow conductor windings is known from DE 10 2018 129 230 A1.

[0006] In internally cooled electric machines with hollow conductor windings, there are technical challenges in electrically and hydraulically connecting the individual hollow conductors. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide an electric machine with a winding formed from hollow conductors, which electric machine includes a connection unit which allows a simple and fast electrical and hydraulic connection of the ends of the individual hollow conductors. [Means for solving the problem]

[0008] This problem is solved according to the invention by the features of patent claim 1. Further developments of the invention emerge from the dependent claims.

[0009] According to the invention, an internally cooled electric machine is proposed with windings formed from hollow conductors, in which the hollow conductors each have an open end via which a coolant can be supplied to or flow out of the hollow conductors. The electric machine according to the invention comprises a connection unit for electrically and fluidly connecting the hollow conductors, the connection unit comprising a connection plate in which a number of electrical conductor paths are integrated, the plate further comprising a number of through openings in which the ends of the hollow conductors are arranged, the hollow conductor ends then being in electrical contact with at least one of the conductor paths integrated in the plate.

[0010] The conductor paths may in principle extend at one level or over several levels inside the plate. The connecting plate preferably comprises one or more buried conductor paths extending below the surface.

[0011] In a particular embodiment of the invention, the connection plate may be formed as a sandwich structure consisting of a number of plates or layers arranged one on top of the other. Each layer may be made of insulating material and may possibly contain one or more conductor paths. The individual layers may for example be glued to one another, overmolded with plastic, resin-connected, welded or otherwise connected together. The layers or plates are preferably arranged one on top of the other in the axial direction of the electric machine.

[0012] According to a special embodiment of the invention, the connection plate, which may be constructed from separate layers, has a recess in its surface in the region of at least one of the through-openings, which allows the hollow conductor ends located in the associated through-opening to be electrically contacted with conductor tracks located below the surface, the recess then reaching from the surface of the connection plate to the bottom of the conductor paths and providing sufficient space for the soldering or welding process.

[0013] The connecting plate is preferably formed in the shape of a ring or may also be made in the form of a circular segment.

[0014] The ends of the hollow conductors are preferably inserted through through openings in the connection plate and project from the surface on the other side, they may also terminate flush with the surface of the connection plate.

[0015] The connection unit, or more precisely the connection plate of the connection unit, is preferably attached to the stator of the electric machine or to the hollow conductor end and has a side facing the winding and a side facing away from the winding, the aforementioned cut-out being preferably provided on the side of the connection plate facing away from the winding.

[0016] The above-mentioned connection unit preferably includes, in addition to the connection plate, a second component or a second segment. The second component has at least one channel fluidly connecting the hollow conductor ends incorporated therein, through which the coolant can be supplied to the hollow conductors or the coolant flowing out of the hollow conductors can be collected. The connection unit may also include two or more incorporated channels.

[0017] The second component is preferably a separate component that is placed on top of the connecting plate and is in close connection with the connecting plate.

[0018] Between the connecting plate and the second component a ring seal is provided, alternatively or additionally both parts may also be glued, welded or otherwise tightly connected together.

[0019] The second component may be made, for example, from plastic or metal.

[0020] The connecting plate, and more particularly the layers of the connecting plate, may be made of insulating material, such as for example GFRP, aramid, ceramic or plastic, or alternatively, the connecting plate or the individual layers may also be made of metal, such as aluminium, provided that electrical insulation for the hollow conductor ends is provided.

[0021] The invention also relates to a connection unit for electrically and fluidly connecting hollow conductors of a winding of an electric machine, the connection unit comprising a connection plate made of an electrically insulating material incorporating a plurality of electrical conductor paths extending into its interior at several levels, the connection plate having a number of through openings for connecting the ends of the hollow conductors.

[0022] The connection unit may comprise a single or multiple coolant channels, which may be selectively provided in the connection plate, in the second component or in both elements. According to a preferred embodiment of the invention, the channels are provided in the form of grooves.

[0023] The connection plate or the entire connection unit may optionally be formed from multiple parts or one piece, which may be produced, for example, by additive manufacturing or injection molding methods.

[0024] The invention is explained in more detail below, by way of example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a cross-sectional view of an electric machine with a hollow conductor winding formed from individual pins and two connection units for electrically and fluidically connecting the individual pins. [Diagram 2] FIG. 2 is a perspective view of one layer of the connection unit of FIG. 1. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of one of the connection units of FIG. 1. [Figure 4] FIG. 2 is an enlarged view of the surface of one layer of the connection unit. [Diagram 5] FIG. 13 is a diagram of a connection unit having two integrated coolant channels. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] 1 shows a cross-sectional view of an electric machine 1 with a stator 2 and hollow conductor windings formed from individual pins. The pins are each made as hollow conductors 5 and include channels therethrough through which a coolant is piped to cool the electric machine 1 during operation.

[0027] On both sides (top and bottom in the figure) of the stator 2, there is respectively a connection unit 3, by means of which the hollow conductors 5 are not only electrically contacted but also fluidly connected to the cooling circuit. Each connection unit 3 comprises a connection plate 6 made of an electrically insulating material, in which are integrated a number of conductor paths 11 which run overlapping one another over several levels. The connection plate 6 further comprises a number of through openings 15 in which the ends 12 of the hollow conductors 5 are respectively arranged, so that the hollow conductor ends 12 are in electrical contact with at least one of the conductor paths 11 integrated in the connection plate 6.

[0028] The connection unit 3 further comprises a coolant channel 8, through which the coolant can be supplied to the hollow conductors 5 or the coolant flowing out of the hollow conductors 5 can be collected. In the embodiment shown, all hollow conductors 5 are fluidically connected in parallel. In the present example, the coolant is supplied from the outside via a central coolant connection 4 (feed pipe) to the connection unit 3 shown above in the figure (see arrow A), then reaches the coolant channel 8 and flows from the coolant channel 8 through the individual hollow conductors 5, which are all fluidically connected in parallel, to the connection unit 3 shown below in the figure. In that connection unit 3, the coolant is collected in the channel 8 and conveyed out to the outside via a central coolant connection (return pipe) (see arrow B).

[0029] In an embodiment, the channels 8 contained in the connection unit 3 are made in a second part 7 or segment, respectively. The second part 7 rests on the connection plate 6 and is tightly connected thereto. Between the second part 7 and the connection plate 6, a ring seal 14 is provided. Alternatively or additionally, both parts 6, 7 may also be glued together or in other ways tightly connected together. The second part 7 may, for example, be manufactured from plastic or metal.

[0030] In the embodiment shown, the connection plates 6 are each formed as a sandwich structure consisting of a number of plates arranged one above the other, in particular of layers 6a-6d arranged one above the other in the axial direction of the electric machine. Each layer 6a-6d is made of insulating material and may possibly contain one or more conductor paths. The individual layers 6a-6d may preferably be glued together or otherwise connected together.

[0031] 2 shows the surface of layer 6b of ring-shaped connecting plate 6. Layer 6b is made of an electrically insulating material on whose surface are embedded a plurality of conductor paths 11. Hollow conductors 5 that are arranged inside the same conductor path 11 are electrically connected together via the conductor paths 11.

[0032] The electric machine 1 shown in Fig. 1 is made three-phase and has correspondingly three external phase connections to which the electrical phases U, V and W are applied. The layer 6b shown in Fig. 2 provides the electrical connections for all three phases U, V, W.

[0033] The individual hollow conductors 5 may be electrically connected via conductor paths 11, e.g. several hollow conductors 5 are connected in series to one coil. Several such coils assigned to the same electrical phases U, V, W may be connected in parallel.

[0034] 3 shows a cross-sectional view of the connection unit 3, in which the coolant channels 8 integrated therein can be clearly seen. The connection unit 3 comprises a connection plate 6 formed from several layers 6a-6d, on top of which a second part 7 with the coolant channels 8 is arranged. Both parts are screwed together using screws 9.

[0035] 4 shows an enlarged view of the surface of layer 6b, in which the cut-outs provided in the surface of connection plate 6 can be clearly seen. The cut-outs 13 serve in particular for soldering or welding, to bring hollow conductor ends 12 in through openings 15 into contact with conductor paths 11 arranged below the surface. As can be seen, the cut-outs 13 reach from the surface of connection plate 6 to the bottom of conductor paths 11, providing sufficient space for the soldering or welding process.

[0036] The connection unit 3, and more particularly the connection plate 6 of the connection unit 3, is preferably attached to the stator 2 of the electric machine 1 and has a side facing the windings and a side opposite the windings. The above-mentioned cut-out 13 is preferably provided on the side of the connection plate 6 opposite the windings, although the cut-out 13 may also be provided on the other side.

[0037] The connecting plate 6, and in particular the layers 6a-6d of the connecting plate 6, may be made of an insulating material, such as for example GFRP, aramid, ceramic or plastic, etc. Alternatively, the connecting plate or the individual layers may also be made of metal.

[0038] 5 finally shows a further variant of the connection unit 3 in which two coolant channels 8 for the feed or return pipe are integrated. This variant accordingly comprises a fluid connection 4 for the feed pipe and a second connection 4 for the return pipe.

Claims

1. 1. An electric machine (1) comprising a winding formed from hollow conductors (5) and a connection unit (3) for electrically and fluidly connecting said hollow conductors (5), each having an open end (12) through which a coolant can be supplied to said hollow conductors (5) or can flow out of said hollow conductors (5), said connection unit (3) comprising a connection plate (6) incorporating a number of electrical conductor paths (11), said connection plate (6) having a number of through openings (15) in which said ends (12) of said hollow conductors (5) are arranged, The electric machine (1), characterized in that the connection plate (6) has on its surface a cutout (13) in the region of at least one of the through openings (15), the cutout (13) enabling a hollow conductor end (12) present in the corresponding through opening (15) to make electrical contact with a conductor path (11) arranged deeper.

2. 2. Electric machine (1) according to claim 1, characterized in that the conductor paths (11) extend inside the connecting plate (6) over several levels.

3. 2. Electric machine (1) according to claim 1, characterized in that the connecting plate (6) is a sandwich structure consisting of several plates (6a-6d) arranged one on top of the other.

4. Electric machine (1) according to claim 3, characterized in that the plates (6a-6d) are made of an insulating material incorporating one or more electrical conductor paths (11).

5. 5. An electric machine (1) according to claim 1, characterized in that the connection unit (3) further comprises a second component (7) having a channel (8) connected to a plurality of hollow conductor ends (12), via which the coolant can be supplied to the hollow conductors (5) or the coolant flowing out of the hollow conductors (5) can be collected.

6. 2. The electric machine (1) according to claim 1, characterized in that the connecting plate (6) and / or the second component (7) have at least one groove on their surface facing the respective other component (6, 7) that is connected to a plurality of hollow conductor ends (12), and via the groove the coolant can be supplied to the hollow conductors (5) or the coolant flowing out of the hollow conductors (5) can be recovered.

7. 7. Electric machine (1) according to claim 5 or 6, characterized in that the second component (7) is placed on the connecting plate (6) and is in tight connection with the connecting plate (6).

8. 2. Electric machine (1) according to claim 1, characterized in that the connecting plate (6) and / or the second component (7) are made in the shape of a ring.

9. 6. Electric machine (1) according to claim 5, characterized in that the second component (7) is made from plastic or metal.

10. 10. An electric machine (1) according to any one of claims 1 to 9, characterized in that the connecting plate (6) is manufactured from an insulating material, such as GFRP, aramid, or plastic, or from a metal, such as aluminum, incorporating conductor paths (11).

11. A connection unit (3) for connecting hollow conductors (5) of a winding of an electric machine (5), comprising a connection plate (6) incorporating a plurality of electric conductor paths (11), said connection plate (6) having a number of through openings (15) for connecting said ends (12) of said hollow conductors (5), The connection plate (6) has on its surface a cutout (13) in the region of at least one of the through openings (15), the cutout (13) enabling a hollow conductor end (12) present in the corresponding through opening (15) to come into electrical contact with a conductor path (11) arranged deeper.

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