Connection device for connecting hollow conductors of an internally cooled electrical machine using sandwich technology and an electrical machine equipped with such a connection device

Abstract

The present invention relates to a connection device (1) for electrically and fluidically connecting hollow conductors (17) of an internally cooled electric machine (23), comprising an electrically conductive connection part (2) having one or more hollow conductor connection parts (6), a side part (24) arranged on one side of the connection part (2), and a sealing part (5) arranged between the connection part (2) and the side part (24). According to the present invention, at least two coolant channels (16) are integrated into the laminate, and coolant can be supplied to the hollow conductors (17) through the coolant channels (16) or coolant flowing out of the hollow conductors (17) can be recovered.

Description

[Technical Field]

[0001] The present invention relates to a connection device for electrically and fluidly connecting a plurality of hollow conductors of an internally cooled electric machine. [Background technology]

[0002] Various configurations of internally cooled electric machines are known from the prior art, with windings formed from hollow conductors having channels passing therethrough through which a coolant is guided to cool the electric machine during operation.

[0003] The windings of known electric machines usually consist of thin hollow conductors wound into coils. In other configurations, the windings include rigid hollow conductors in the shape of U-shaped bends (hairpins) or rods (pins). The pins or hairpins are rigid winding components, usually made of copper, inserted into slots in the stator of the electric machine to generate the magnetic field required during operation of the electric machine.

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

[0005] Galvanic isolation of fluid connections from the supply potential is a technical challenge in internally cooled electric machines with hollow conductor windings. Known implementations of hollow conductor connection parts in which galvanic isolation is achieved using ceramic balls are described, for example, in EP 3 357 143 A2. A further hollow conductor connection part is known from WO 2015 / 150 556 A1, which includes multiple components assembled into a stack with integrated cooling channels. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a connection device for electrically and fluidly connecting a plurality of hollow conductors of an internally cooled electric machine, which connection device is simple to assemble and can be produced quickly and inexpensively.

[0007] This problem is solved according to the invention by the features of patent claim 1. Further embodiments of the invention emerge from the dependent claims. [Means for solving the problem]

[0008] According to the invention, a connection device is proposed for the electrical and fluid connection of hollow conductors of an internally cooled electrical machine, which connection device comprises at least: a conductive connection part having one or more hollow conductor connection parts, each of which is electrically and fluidly connected to a hollow conductor; a side piece arranged on one side of the connecting piece, the connecting piece and the side piece being separate pieces assembled in a stack; - an internal refrigerant channel extending through the connection piece, the refrigerant channel being fluidly connected to one or more hollow conductors so that refrigerant flowing out of the one or more hollow conductors can be collected in the refrigerant channel or refrigerant present in the refrigerant channel can be supplied to the one or more hollow conductors.

[0009] Due to its modular nature, the connection device can be easily adapted to given requirements and may consist of more or fewer electrical connection parts depending on the number of electrical phases of the machine. For this purpose, it is only necessary to integrate the individual components required for this (connection parts, seals, insulators) into a laminate-like structure.

[0010] A "side piece" can in principle be any component that is arranged on one side of the connection piece and is part of a laminate-like structure. The side piece can correspondingly be an insulator, a seal, or another component. Further components, such as, for example, an insulator and / or a further seal, may be arranged between the connection piece and the side piece.

[0011] The connecting piece is preferably made of a metallic material such as Cu. Internal cooling channels preferably extend within the metallic material.

[0012] The seal is preferably embodied as a flat seal.

[0013] In a specific embodiment of the invention, the connection device is formed as a laminate assembly whose front end is terminated by electrically insulating side pieces, preferably at least one of the front side pieces having a central coolant connection through which coolant can be supplied to the coolant channels or through which coolant exiting the coolant channels can be discharged.

[0014] The direction in which the individual components of the connection device are stacked extends along a substantially linear axis. The use of wedge-shaped components could result in curved, e.g., ring-shaped, or other geometries of the stack assembly.

[0015] The individual components of the connecting device, ie at least the connecting part and the side part, are preferably embodied in the form of a plate.

[0016] The one or more hollow conductors connected to the connection component preferably face in the connection region in a direction substantially transverse to the direction in which the connection component and the side component are stacked (stacking direction). The hollow conductor connections are preferably all located on the same side of the stack assembly.

[0017] In a specific embodiment, the connection device comprises at least one electrically conductive connection part and a sealing part. In this case, the internal coolant channel preferably passes through the connection part and the sealing part. In the case of a multi-phase embodiment of the connection device, the connection device comprises a plurality of adjacently arranged connection parts, with at least one sealing part or insulator disposed between each of two adjacently arranged connection parts. In a specific embodiment of the present invention, for example, at least one sealing part and one insulator may be disposed between two adjacently arranged connection parts. Thus, a multi-phase embodiment of the connection device comprises a plurality of adjacently arranged connection parts, a plurality of sealing parts, and optionally a plurality of side parts.

[0018] The connection pieces preferably comprise provisions such as terminals, cable lugs, etc. for connecting the electrical phases (U, V, W).

[0019] In a specific embodiment, the connection device has at least two integrated coolant channels through which coolant can be supplied to the hollow conductor or coolant flowing out of the hollow conductor can be collected.

[0020] The connection device may further comprise a clamping device by means of which the connection part, the side part and, if necessary, further components of the stack assembly are clamped together. In one embodiment of the invention, the clamping device may include one or more clamp bolts extending through the connection device. Alternatively, the clamping device may surround the stack assembly like a clamp.

[0021] The individual components of the stacked connection device may also be glued together.

[0022] The invention further relates to an electric machine with hollow conductor windings and a connection device designed using stacking or sandwich techniques for electrically and fluidly connecting the hollow conductors.

[0023] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of a three-phase electric machine known from the prior art with hollow conductor windings; [Figure 2] 1 shows an embodiment of an electrical / hydraulic connection device for a three-phase electric machine with star connection; [Figure 3] 3 is a side view of a portion of the electrical / fluidic connection device of FIG. 2. [Figure 4] 1 is a cross-sectional view of an electrical / fluidic connection device taken along the longitudinal axis of the connection device. [Figure 5] FIG. 1 shows an embodiment of an electrical / fluidic connection device for a three-phase electric machine with star connection, in which the part designed for the feed pipe and the part designed for the return pipe of the cooling circuit are arranged spatially separated from each other. [Figure 6] FIG. 1 shows an embodiment of an electrical / fluidic connection device for a three-phase electric machine with star connection, in which the part designed for the feed pipe and the part designed for the return pipe of the cooling circuit are combined in one unit. DETAILED DESCRIPTION OF THE INVENTION

[0025] 1 shows a schematic diagram of a known three-phase synchronous machine 25 with an inner-disposed stator 24 and an outer-disposed rotor (not shown). The electrical phases are labeled L1, L2, L3 or 0 and are interconnected in a star configuration.

[0026] The stator 24 includes six teeth 20 on which the individual windings 18 are arranged. Each winding 18 consists of a hollow conductor 17 through which a coolant flows to cool the electric motor 25 during operation. In the illustrated embodiment, the coolant is supplied to the hollow conductor ends and star point 0 of each individual winding 18 and is discharged again via an internal T-shaped connection piece 26.

[0027] 1 further comprises a cooling system having a coolant pump 21 and a heat exchanger 22. The pump 21 pumps coolant through various coolant lines 19 to the phase ends of the windings 18 and to star point 0, from where the coolant enters the respective hollow conductors 17. The coolant then flows through the respective hollow conductors 17 and back towards the heat exchanger 22 via the T-connectors 26, where it is cooled and then flows further to the pump 21.

[0028] The electrical and fluid connection of the individual hollow conductors 17 is a relatively complex solution in this electric machine. Therefore, an alternative connection device with a sandwich-like structure is proposed, as illustrated in the following figure. The connection device according to the invention can in principle be used for all internally cooled electric machines with single or multiple phases, as well as for other internally cooled electric devices, such as electromagnets, valves, etc.

[0029] FIG. 2 shows an electrical / fluidic connection device 1 for hollow conductors 17 of an internally cooled electric machine 25 according to a first embodiment of the present invention. In this embodiment, the connection device 1 comprises four adjacently arranged connection parts 2 made of a conductive material, e.g., Cu, one for each of the phases U, V, and W and one at the star point*. The four connection parts 2 are electrically and fluidically connected to the corresponding hollow conductors 17. For this connection, each connection part 2 includes a plurality of hollow conductor connection sections 6, to which hollow conductor ends are respectively connected. The hollow conductor ends can be attached to the connection part 2, for example, by soldering, welding, or other methods. Furthermore, each connection part 2 includes a terminal 3 to which one of the electrical phases (U, V, W, or *) can be connected per cable lug.

[0030] Between each pair of adjacent connection parts 2 there is arranged a first seal 5, an insulator 4 and a further seal 5. The seals 5 are preferably embodied as flat seals. At the two front side ends (left and right in the figure) of the connection device 1 there are respectively electrically insulating side parts 24 which form the end points of the assembly. Overall, a laminate- or sandwich-like structure results.

[0031] In the illustrated embodiment, the individual components 2, 4, 5, 24 of the stack assembly are clamped using a clamping device 11. This presses the individual components 2, 4, 5, 24 against one another, simultaneously sealing the coolant channels 16 running through them. Such a connection device 1 is easy to install and can be configured with more or fewer connection pieces 2 depending on the number of electrical phases of the machine 25 to be connected or the number of series connections. The connection pieces 2 can be used not only for phase connection but also for electrical interconnections according to a specific winding scheme. To reduce the fluid pressure required to flow through the coil, it is also possible to separate the coil and electrically connect the coil parts at the connection pieces 2. In this case, the individual parts of the coil can be electrically connected in series but supplied with coolant in parallel, thereby reducing the pressure required for flow through.

[0032] The internal configurations of the connection device 1 and the clamping device 11 are shown in more detail in Figures 3 and 4. In the drawings, Figure 3 shows a side view of a portion of the electrical / fluidic connection device 1 of Figure 2, and Figure 4 shows a cross-sectional view of the connection device 1 along its longitudinal axis. As can be seen from Figures 3 and 4, a first coolant channel 16 extends through the left part of the sandwich-like structure and is fluidly connected to the hollow conductor connections 6 of the connection parts 2 for the U, V, and W phases. Another coolant channel 16 extends to the right part of the connection device 1 and is fluidly connected to the hollow conductor connections 6 of the connection parts 2 for the star point*. The side parts 24 arranged at the ends each include a central coolant connection 8, through which coolant can be supplied to the coolant channel 16 or coolant flowing out of the coolant channel 16 can be discharged (see arrows VL and RL).

[0033] In the operating mode of the cooling circuit shown here, the refrigerant connection 8 on the left side shown in Figure 4 functions as a refrigerant inlet (feed pipe), and the refrigerant connection 8 on the right side functions as a refrigerant outlet (return pipe). The refrigerant channels 16 on the left side correspond to distribution channels 9, through which the refrigerant is supplied to the individual hollow conductors 17 (see the outward arrows at the hollow conductor ends 17). The refrigerant channels 16 on the right side correspond to return channels 10, in which the refrigerant flowing out of the individual hollow conductors 17 is collected (see the inward arrows at the hollow conductor ends at the star points).

[0034] In this embodiment, the clamping device 11 includes three clamping bolts 12 or threaded bolts that extend entirely through the connecting device 2. Nuts 13 are located on the protruding ends of the clamping bolts 12 that tighten the device.

[0035] 5 shows an embodiment of an electrical / hydraulic connection device 1 for a three-phase electric machine 25 with a star connection, in which the parts of the connection device 1 configured for the inlet and outlet pipes of the cooling circuit are spatially separated from each other. In this case, the left part contains the connection parts 2 for all three phases U, V, and W, while the right part contains only one star-point connection part 2. The division of the connection device can also be implemented differently.

[0036] FIG. 6 further shows an embodiment of the electrical / hydraulic connection device 1 for a three-phase electric machine 25 with star connection, in which the part designed for the feed pipe and the part designed for the return pipe of the cooling circuit are combined in a single unit.

Claims

1. A connection device (1) for electrically and fluidly connecting hollow conductors (17) of an internally cooled electrical device, in particular an electrical machine (23), comprising: - at least one electrically conductive connection piece (2) having one or more hollow conductor connections (6) for connecting the ends of one or more hollow conductors (17); - at least one electrically insulating side part (24) arranged on one side of said connection part (2), In a connection device (1), the at least one connection part (2) and the at least one side part (24) are arranged as a stack, At least two refrigerant channels (16) are integrated into the laminate, and refrigerant can be supplied to the hollow conductor (17) through the refrigerant channels (16) or refrigerant flowing out from the hollow conductor (17) can be recovered.

2. 2. The connection device (1) according to claim 1, characterized in that the one or more hollow conductors (17) are connected to the connection part (2) in a direction extending substantially transverse to the direction in which the connection part (2) and the side part (24) are stacked.

3. 2. The connection device (1) according to claim 1, characterized in that the internal coolant channel (16) extends substantially in the direction in which the connection piece (2) and the side piece (24) are stacked.

4. 2. A connection device (1) according to claim 1, characterized in that it comprises a plurality of connection parts (2) arranged adjacent to one another, and at least one sealing part (5) is arranged between two connection parts (2) arranged adjacent to one another.

5. 2. A connection device (1) according to claim 1, characterized in that it is formed as a laminate assembly extending along a substantially linear axis.

6. 2. A connection device (1) according to claim 1, characterized in that it is formed as a laminate assembly, said laminate assembly being terminated at its front end by an electrically insulating side piece (24).

7. 7. The connection device (1) according to claim 6, characterized in that at least one of the side parts (24) is provided with a central refrigerant connection (8) via which refrigerant can be supplied to the refrigerant channels (16) or refrigerant flowing out of the refrigerant channels (16) can be discharged.

8. 2. A connection device (1) according to claim 1, characterized in that a clamping device (11) is provided by means of which the connection part (2), the side part (24) and, if necessary, further components of the stack assembly are clamped together.

9. 2. A connection device (1) according to claim 1, characterized in that the connection part (2) comprises provisions (3) for connecting electrical phases (U, V, W).

10. 9. A connecting device (1) according to claim 8, characterized in that the clamping device (11) comprises a clamping bolt (12) extending through the connecting device (2).

11. An internally cooled electrical device, in particular an electrical machine, comprising a hollow conductor winding (18) and a connection device (1) for electrically and fluidly connecting a hollow conductor (17) according to any one of claims 1 to 10.

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