Connection device in sandwich technology for connecting waveguides of an internally cooled electrical machine and electrical machine with such a connection device

Abstract

Connecting device (1) for the electrical and hydraulic connection of electrical waveguides (17) of an internally cooled electrical device, in particular an electrical machine (23), comprising: - an electrically conductive connecting part (2) with one or more waveguide connections (6) for connecting the end(s) of one or more waveguides (17); - at least one electrically insulating side part (24) arranged on one side of the connecting part (2); wherein the connecting part (2) and the side part (24) are arranged as a stack; characterized in that at least two coolant channels (16) are integrated into the stack, via which a coolant can be fed into the waveguides (17) or via which coolant emerging from the waveguides (17) can be collected.

Description

The invention relates to a connecting device for electrically and hydraulically connecting a plurality of electrical waveguides of an internally cooled electrical machine.BACKGROUND OF THE INVENTIONA wide variety of designs of internally cooled electric machines with a winding formed from hollow conductors are known from the prior art. The waveguides have a continuous channel through which a coolant is conducted in order to cool the electric machine during operation.The winding of known electric machines usually consists of a thin hollow wire which is wound into coils. In other designs, the winding comprises rigid hollow conductors in the form of hairpins (hair pins) or rods (pins). The pins or hair pins are usually rigid winding pieces which are produced from copper and are inserted into slots in the stator of the electric machine and generate the required magnetic field during operation of the electric machine.The waveguides have open ends via which a coolant can be fed into the waveguides or can emerge from the waveguides. On their outer surface, the known waveguides are provided with an electrically insulating layer.In the case of internally cooled electrical machines with a hollow conductor winding, the galvanic separation of the hydraulic connection from the electrical supply potential in particular represents a technical challenge. A known embodiment of a waveguide connection piece, in which the galvanic separation is effected by means of a ceramic ball, is described, for example, in EP 3 357 143 A2. A generic waveguide connector piece which comprises a plurality of components joined together to form a stack with a coolant channel integrated therein is known from WO 2015 / 150 556 A1.OBJECT OF THE INVENTIONIt is an object of the present invention to provide a connecting device for the electrical and hydraulic connection of a plurality of electrical waveguides of an internally cooled electrical machine, which is of simple construction and can be produced quickly and economically.This object is achieved according to the invention by the features specified in claim 1. Further embodiments of the invention are evident from the dependent claims.According to the invention, a connecting device for electrically and hydraulically connecting the electrical waveguides of an internally cooled electrical machine is proposed, which connecting device comprises at least the following:an electrically conductive connection part having one or more waveguide connections to each of which a waveguide is electrically and hydraulically connected;a side part disposed on a side of the connector; wherein the connector and the side part are separate components joined together into a stack;wherein at least two coolant channels are integrated in the stack, via which a coolant can be fed into the hollow conductors or coolant emerging from the hollow conductors can be collected.Due to its modularity, the connection device can be easily adapted to the specified requirements and, depending on the number of electrical phases of the machine, can be configured with more or fewer electrical connection parts. The individual components required for this purpose (connection parts, seals, insulators) need only be integrated into the stack-like structure for this purpose.A "side part" can in principle be any component which is arranged on one side of the connection part and is part of the stack-like structure. A side part can accordingly be an insulator, a seal or another component. Further components, such as an insulator and / or a further seal, can be arranged between the connection part and the side part.The connection part is preferably made of a metallic material, such as Cu. The internal coolant channel preferably runs in the metallic material.The seal is preferably designed as a flat seal.In a specific embodiment of the invention, the connection device is formed as a stack arrangement which is terminated at its end-face ends in each case by an electrically insulating side part. Preferably, at least one of the end side parts has a central coolant connection via which a coolant can be fed into the coolant channel or coolant emerging from the coolant channel can be discharged.The direction in which the individual components of the connection device are stacked runs substantially along a straight line. Wedge-shaped components could also be used to produce a curved, for example annular, or another geometry of the stack arrangement.The individual components of the connection device, namely at least the connection part and the side part, are preferably plate-shaped.In the region of its connection, the waveguide or waveguides connected to the connection part preferably point in a direction which runs substantially transversely to a direction in which the connection part and the side part are stacked (stacking direction).In a specific embodiment, the connection device comprises at least one electrically conductive connection part and a seal. The integrated coolant channels in this case preferably run through the connection part and the seal.In the case of a polyphase embodiment of the connection device, the latter correspondingly comprises a plurality of connection parts arranged next to one another, at least one seal being arranged in each case between two connection parts arranged next to one another. In a special embodiment of the invention, at least one seal and one insulator, for example, can be arranged between two connection parts arranged next to one another. A polyphase embodiment of the connection device consequently has a plurality of connection parts arranged next to one another, a plurality of seals and optionally a plurality of side parts.Said connector preferably has a device for connecting an electrical phase (U, V, W), such as a terminal, a cable lug or the like.The connection device can furthermore have a clamping device, with which the connection part, the side part and optionally further components of the stack arrangement are clamped against one another. In one embodiment of the invention, the clamping device can comprise one or more clamping bolts which extend through the connection device. Alternatively, the clamping device can also encompass the stack arrangement in accordance with a clamp.The individual components of the connection device stacked on top of one another can also be glued to one another.The present invention further relates to an electric machine having a hollow conductor winding and a connecting device embodied in stacking or sandwich technology for electrically and hydraulically connecting the electric hollow conductors.BRIEF DESCRIPTION OF THE DRAWINGSThe invention is explained in more detail below by way of example with reference to the attached drawings. The following are shown: FIG. 1 shows a schematic view of a three-phase electric machine known from the prior art with hollow-wire windings; FIG. 2 shows an embodiment of an electrical / hydraulic connection device for a three-phase electric machine with a star connection; FIG. 3 shows a side view of a part of the electrical / hydraulic connection device from FIG. 2 ; FIG. 4 shows a sectional view of an electrical / hydraulic connection device along a longitudinal axis of the connection device; FIG. 5 shows an embodiment of an electrical / hydraulic connection device for a three-phase electric machine with a star connection, in which a part designed for the forward flow and a part designed for the return flow of the cooling circuit are arranged spatially separated from one another; FIG. 6 shows an embodiment of an electric / hydraulic connection device for a three-phase electric machine with a star connection, in which a part designed for the forward flow and a part designed for the return flow of the cooling circuit are combined in one unit.EMBODIMENTS OF THE INVENTIONFIG. 1 shows a schematic view of a known three-phase synchronous machine 25 with an internal stator 24 and an external rotor (not shown). The electrical phases are designated L1, L2 and L3 or 0 and are connected in a star connection.The stator 24 comprises six teeth 20 on which the individual windings 18 are arranged. The windings 18 each consist of a hollow wire 17 through which a coolant flows in order to cool the electric motor 25 during operation. In the exemplary embodiment shown, coolant is fed to the waveguide ends of the individual windings 18 and at the star point 0 and is discharged again via internal, T-shaped connecting pieces 26.The synchronous machine shown in FIG. 1 further comprises a cooling system with a coolant pump 21 and a heat exchanger 22, the pump 21 pumps coolant through different coolant lines 19 to the phase-side ends of the windings 18 and to the neutral point 0 where the coolant enters the respective hollow conductors 17. The coolant then flows in each case through the hollow conductors 17 and via the T-shaped connecting pieces 26 back in the direction of the heat exchanger 22, where it is cooled and flows further to the pump 21.The electrical and hydraulic connection of the individual waveguides 17 is relatively complex in this electric machine. Therefore, an alternative connection device with a sandwich-like structure is proposed, as is illustrated by way of example in the following figures. The connection device according to the invention can in principle be used on all internally cooled electric machines with one or more phases and on other internally cooled devices, such as electromagnets, valves, etc.FIG. 2 shows an electrical / hydraulic connection device 1 for the waveguides 17 of an internally cooled electrical machine 25 according to a first embodiment of the invention. In this embodiment, the connection device 1 comprises four connection parts 2 arranged next to one another, one for each phase U, V, W and one for the neutral point *, made of an electrically conductive material, such as Cu, to each of which the associated waveguides 17 are electrically and hydraulically connected. For this purpose, each connection part 2 comprises a plurality of waveguide connections 6, to each of which a waveguide end is connected. The waveguide ends can be soldered or welded, for example, or otherwise mounted on the connection part 2. In addition, the connection parts 2 each comprise a terminal 3 to which one of the electrical phases (U, V, W and *, respectively) can be connected by cable lug.Between two adjacent connection parts 2, a first seal 5, an insulator 4 and a further seal 5 are arranged in each case. The seals 5 are preferably designed as flat seals. At the two front ends of the connection device 1 (left and right in the figure) there is in each case an electrically insulating side part 24, which forms the termination of the arrangement. Overall, a stacked or sandwich-like structure results.In the embodiment shown here, the individual components 2, 4, 5, 24 of the stack arrangement are clamped by means of a clamping device 11. As a result, the individual components 2, 4, 5, 24 are pressed against one another, as a result of which the coolant channels 16 running in the interior are simultaneously sealed off. Such a connection device 1 can be easily mounted and configured with more or fewer connection parts 2 depending on the number of electrical phases or the serial connections of the machine 25 to be contacted. Apart from the phase connection, a connection part 2 can also serve to implement the electrical interconnection in accordance with a specific winding scheme. In order to reduce the hydraulic pressure required for a coil to flow through, it is also possible to cut a coil and electrically connect the coil parts in the connection part 2. The individual parts of the coil are then electrically connected in series, but can be supplied with coolant in parallel, as a result of which the pressure required for the flow through decreases.In the following FIGS. 3, 4, the internal construction of the connection device 1 and the clamping device 11 are shown in more detail. In this case, FIG. 3 shows a side view of a part of the electrical / hydraulic connection device 1 from FIG. 2, and FIG. 4 shows a sectional view of the connection device 1 along a longitudinal axis of the connection device. As can be seen in FIGS. 3, 4, a first coolant channel 16 runs through the left-hand part of the sandwich-like structure, said first coolant channel being hydraulically connected to the waveguide connections 6 of the connection parts 2 for the phases U, V, W. In the right-hand part of the connection device 1, a different coolant channel 16 runs, which is hydraulically connected to the waveguide connections 6 of the connection part 2 for the star point *. The side parts 24 arranged at the ends each comprise a central coolant connection 8, via which coolant can be fed into the coolant ducts 16 or coolant emerging from the coolant ducts 16 can be discharged (see arrows VL, RL).In the operating mode of the cooling circuit shown here, the left-hand coolant connection 8 shown in FIG. 4 serves as coolant inlet (flow) and the right-hand coolant connection 8 as coolant outlet (return). The left coolant channel 16 is correspondingly a distributor channel 9, via which the coolant is fed into the individual waveguides 17 (see the outward pointing arrows at the waveguide ends 17). The right coolant channel 16 is correspondingly a collecting channel 10, in which the coolant emerging from the individual waveguides 17 is collected (see the inwardly pointing arrows at the waveguide ends of the star point).In this embodiment, the clamping device 11 comprises three clamping bolts 12 or threaded bolts which extend through the entire connecting device 2. Nuts 13 are arranged at the protruding ends of the clamping bolts 12 and are used to clamp the device.FIG. 5 shows an embodiment of an electric / hydraulic connection device 1 for a three-phase electric machine 25 with a star connection, in which a part of the connection device 1 designed for the forward flow and a part designed for the return flow of the cooling circuit are arranged spatially separated from one another. The left-hand part in this case comprises connection parts 2 for all three phases U, V, W, and the right-hand part comprises only one connection part 2 for the neutral point. The division of the connection device can also be designed differently.FIG. 6 once again shows an embodiment of an electric / hydraulic connection device 1 for a three-phase electric machine 25 with a star connection, in which a part designed for the forward flow and a part designed for the return flow of the cooling circuit are combined in a single unit.

Claims

Connection device (1) for electrically and hydraulically connecting electrical waveguides (17) of an internally cooled electrical device, in particular of an electrical machine (23), comprising: - an electrically conductive connection part (2) having one or more waveguide connections (6) for connecting the end or ends of one or more waveguides (17); - at least one electrically insulating side part (24) arranged on one side of the connection part (2); wherein the connection part (2) and the side part (24) are arranged as a stack; characterized in that at least two coolant channels (16) are integrated in the stack, via which coolant can be fed into the waveguides (17) or coolant emerging from the waveguides (17) can be collected.Connection device (1) according to claim 1, characterised in that the waveguide or waveguides (17) are connected to the connection part (2) in a direction which runs substantially transversely to a direction in which the connection part (2) and the side part (24) are stacked.The connection device (1) according to claim 1, characterized in that the internal coolant channel (16) extends substantially in a direction in which the connection part (2) and the side part (24) are stacked.Connection device (1) according to claim 1, characterised in that it comprises a plurality of connection parts (2) arranged next to one another, wherein at least one seal (5) is arranged in each case between two connection parts (2) arranged next to one another.Connection device (1) according to claim 1, characterized in that it is formed as a stack arrangement extending substantially along a straight axis.Connection device (1) according to claim 1, characterised in that it is formed as a stack arrangement which is terminated at its front ends in each case by an electrically insulating side part (24).Connection device (1) according to claim 6, characterised in that at least one of the side parts (24) provides a central coolant connection (8), via which a coolant can be fed into the coolant channel (16) or coolant emerging from the coolant channel (16) can be discharged.Connection device (1) according to claim 1, characterised in that a clamping device (11) is provided, by means of which the connection part (2) and the side part (24) and optionally further components of the stack arrangement are clamped against one another.Connection device (1) according to Claim 1, characterized in that the connection part (2) has a device (3) for connecting an electrical phase (U, V, W).Connection device (1) according to claim 8, characterised in that the clamping device (11) comprises a clamping bolt (12) which extends through the connection device (1).Internally cooled electrical device, in particular electrical machine, having a hollow conductor winding (18) and a connection device (1) for electrically and hydraulically connecting the electrical hollow conductors (17) according to one of the preceding claims.

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