WINDING PIECE AND ELECTRICAL MACHINE WITH SUCH A WINDING PIECE

Description

[0001] The invention relates to a winding piece, in particular in the form of a hairpin, which is intended to be inserted into the slots of an electric motor, as well as to an electric machine with such winding pieces. Background of the invention

[0002] Internally cooled electric machines with a winding made of an electrically conductive hollow wire are known from the prior art. The hollow wire is typically a round wire with a longitudinal channel through which a coolant can be passed to cool the electric machine. This allows the rated power of such electric machines to be increased several times over compared to conventional electric machines. A typical internally cooled electric motor with a hollow wire winding is known, for example, from WO 2015 / 150556 A9.

[0003] In addition to electrical machines with round wire windings, there are also electrical machines whose windings are manufactured using pin or hairpin technology. Pins or hairpins are rigid winding pieces, usually made of copper, that are inserted into the slots of an electrical machine. When inserted, a portion of the pins or hairpins protrudes from the slots at the head of the stator. The protruding ends are then usually interlaced and welded together to form a complete coil.

[0004] State-of-the-art pins are usually rod-shaped, rigid elements with a rectangular profile. Hairpins typically comprise two legs and a curved transition area connecting the two legs. The legs have a rectangular profile adapted to the cross-section of the groove.

[0005] An electric motor with a winding piece designed to be inserted into a slot of the electric motor is known, for example, from GB 1 179 553 A, US 9 515 530 B2, or DE 11 28 541 A. DE 698 30 869 T2 further describes an electric machine with a winding piece having a central section with a rectangular profile and two end sections with a round profile. In this case, the winding piece is a waveguide coil whose profile has been subsequently transformed from round to rectangular in a partial area. However, connecting several such winding pieces to form a complete winding is technically relatively difficult. Object of the present invention

[0006] It is therefore an object of the present invention to provide an electrical machine with a winding formed from pins or hairpins, which has a high fill factor and whose winding pieces can be connected to one another easily and tightly.

[0007] This object is achieved according to the invention by the features mentioned in claim 1. Further embodiments of the invention emerge from the subclaims.

[0008] According to the invention, an electrical machine is proposed with a winding for generating an electromagnetic field, which winding is formed from winding pieces in the form of pins or hairpins. The winding pieces have a first section with a rectangular profile, which is adapted to the cross-section of a slot of an electrical machine, and two end sections with a round profile. The winding pieces according to the invention are also designed as waveguides with a continuous channel through which a coolant can be conducted. Due to the special profile of the end sections, the winding pieces can be hydraulically connected to one another much more easily. This also makes it possible to solder a connecting element required for this purpose to the ends.

[0009] According to another embodiment of the invention, the winding piece has the shape of a hairpin, wherein the winding piece comprises two legs and a curved transition region that connects the two legs. Each of the legs comprises a first section with a profile adapted to the cross-section of the associated slot, as well as an end section that has a round profile. The ends of the individual winding pieces can thus be mechanically and hydraulically connected to other winding pieces much more easily via connecting elements. The winding piece according to the invention is further designed as a waveguide that has a continuous channel through which a coolant can be conducted.

[0010] A winding piece according to the invention can, in principle, be dimensioned such that it fills a slot alone or together with one or more additional winding pieces arranged in the same slot. In the case of a single winding piece per slot, the profile of the (first) section running in the slot is preferably designed such that the section lies in the slot essentially free of play. In the case of multiple winding pieces per slot, the profile of the sections running in the slot is preferably designed such that all winding pieces together fill the slot essentially free of play.

[0011] The legs have a rectangular, in particular square, profile at their first section, which is adapted to the inner cross-section of the corresponding groove.

[0012] A winding piece according to the invention is preferably made of copper, aluminum or an alloy of one of the materials mentioned.

[0013] On its outer surface, the winding piece according to the invention is provided with an electrically insulating layer.

[0014] The electrical machine according to the invention also comprises a plurality of tubular connecting elements arranged at the open ends of the winding sections to fluidically connect the winding sections to one another. The connecting elements are tubular and each have a round inner cross-section at both ends, which is dimensioned such that the connecting elements can be plugged onto the round end sections of the winding sections.

[0015] The connecting elements according to the invention are preferably curved in an arc shape and can, for example, be horseshoe-shaped or U-shaped.

[0016] According to another embodiment of the invention, a connecting element can also be provided that connects more than two winding sections to one another. Such a connecting element preferably comprises terminals for more than two winding sections. According to a specific embodiment of the invention, the connecting element can have an internal collecting or distribution channel that is connected to more than two winding sections. Such a connecting element with a collecting or distribution channel can be dimensioned so that all winding sections of an electrical machine can be connected to it. Short description of the drawings

[0017] The invention is explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 shows a perspective view of a hairpin-shaped winding piece for an electrical machine; Fig. 2 shows a detailed view of a stator of an electrical machine with several hairpin-shaped winding pieces; and Fig. 3 shows a view of a bar-shaped winding piece for an electrical machine. Embodiments of the invention

[0018] Fig. 1 shows a perspective view of a hairpin-shaped winding piece for the winding of an electrical machine. Such winding pieces 1 are also referred to as hairpins because they have the shape of a hairpin.

[0019] To produce an electromagnetic winding of an electrical machine, several hairpins are inserted into the slots of a stator of the electrical machine and electrically connected to each other to form one or more coils.

[0020] The Fig. 1 The winding piece 1 shown comprises two legs 2 and a curved transition area 3, which connects the two legs 2 to one another. The legs 2 each have a first section 4 with a profile which is adapted to the cross-section of the slots of the electrical machine, so that they are arranged in the respective slot essentially without play. The profile of the first section 4 of the legs 2 is essentially square in the illustrated embodiment, but could also be rectangular or have a different shape. At their free end sections 5, the legs 2 each have a round profile. This has the advantage that the end sections 5 can be easily and securely connected via tubular connecting elements 6, as shown for example in Fig. 2 shown, can be fluidically connected to each other.

[0021] The hairpin-shaped winding piece 1 of Fig. 1 further comprises a continuous channel 9 through which a coolant can be conducted in order to cool the winding of the electrical machine during operation.

[0022] The Fig. 1 The winding piece 1 shown can be made of copper, for example. Its outer surface is preferably provided with an electrically insulating layer.

[0023] Fig. 2 shows an enlarged view of a head section of a stator 8, wherein the end sections 5 of the winding pieces 1 protruding from the slots 7 are clearly visible. In order to obtain a closed coolant circuit, the free ends or end sections 5 of the winding pieces 1 are hydraulically connected to one another via several tubular connecting elements 6. In the illustrated embodiment, the connecting elements 6 are U-shaped and each have a round inner diameter at their open ends so that they can be plugged onto the round end sections 5 of the winding pieces 1. The round design has the advantage that the connecting elements 6 can be plugged in any orientation, which makes the process relatively easy to automate.

[0024] Fig. 3Finally, a view of a rod-shaped winding section 1 for an electrical machine is shown. The rod-shaped winding section 1 has a central section 4 with a rectangular profile and two end sections 5 with a round profile.

[0025] Note: The project leading to this application has received funding from the EU's Horizon 2020 research and innovation programme under grant agreement No 804219.

Claims

1. Electrical machine with a winding for generating an electromagnetic field, which is formed from winding pieces (1) in the form of pins or hairpins which are intended to be inserted into one or more slots (7) of an electrical machine, the winding pieces (1) being designed as a hollow conductor with a continuous channel (9) through which a coolant can be passed, characterized in that - the winding pieces (1) have a first section (4) with a rectangular profile and two end sections (5) with a round profile, and - the winding pieces (1) are connected to one another via one or more connecting elements (6), which are tubular in shape and each have a round internal cross-section at their two ends, which is adapted to the round profile of the end sections (5) of the winding pieces (1).

2. Electric machine according to claim 1, characterized in that the winding piece (1) is made of copper, aluminum or an alloy of one of the said materials.

3. Electric machine according to claim 1, characterized in that the connecting elements (6) are curved in the shape of an arc.

4. Electrical machine according to claim 1, characterized in that at least one of the connecting elements (6) has connections for more than two winding pieces (1).

5. Electrical machine according to claim 1, characterized in that at least one of the connecting elements (6) has an internal collecting and / or distributing channel which is connected to at least three of the connections for the winding pieces (1).