Connecting device for connecting hollow conductors of internally cooled electric machine using lamination techniques

Abstract

The invention relates to a connecting device (1) for electrically and hydraulically connecting an electric hollow conductor (17) of an inner-cooled electric machine (23), comprising: an electrically conductive connecting part (2) having one or more hollow conductor connections (6); the side piece (24) is arranged on one side of the connecting piece (2); and the sealing piece (5) is arranged between the connecting piece (2) and the side piece (24). According to the invention, at least two coolant channels (16) are integrated in the stack, via which coolant can enter the hollow conductor (17) or coolant flowing out of the hollow conductor (17) can be collected.

Description

Technical Field

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

[0002] The prior art discloses various configurations of internally cooled electric machines having windings composed of hollow conductors. The hollow conductors have continuous channels through which a coolant is guided for cooling the operating electric machine.

[0003] The windings of known electric machines typically consist of thin hollow wires wound into coils. In other configurations, the windings include rigid hollow conductors in the form of hairpins or pins. The pins or hairpins are typically rigid copper winding assemblies that are inserted into the stator slots of the electric machine and generate the required magnetic field during operation of the electric machine.

[0004] The hollow conductors have open ends through which the coolant can enter or exit the hollow conductors. The outer surfaces of the known hollow conductors are provided with electrical insulation layers.

[0005] In an internally cooled electric machine with a hollow conductor winding, electrically isolating a hydraulic connection from the supply potential is a major technical challenge. For example, EP3357143A2 describes a known embodiment of a hollow conductor connection in which electrical isolation is achieved by means of ceramic balls. WO2015 / 150556A1 discloses another hollow conductor connection that includes a plurality of stacked components and integrated coolant channels. Summary of the Invention

[0006] The object of the present invention is to provide a connecting device for electrically and hydraulically connecting a plurality of hollow electrical conductors of an internally cooled electric machine, which has a simple structure and can be manufactured quickly and at low cost.

[0007] According to the present invention, the object is achieved by the features specified in claim 1. Further designs of the present invention result from the dependent claims.

[0008] According to the present invention, a connecting device for electrically and hydraulically connecting hollow electrical conductors of an internally cooled electric machine is proposed, which at least comprises the following parts:

[0009] -- a conductive connecting piece having one or more hollow conductor joints, each hollow conductor being electrically and hydraulically connected to a corresponding one of the hollow conductor joints;

[0010] -- a side piece arranged on one side of the connecting piece, wherein the connecting piece and the side piece are separate components combined into a stack;

[0011] --An internal coolant passage that extends through the connection member, wherein the coolant passage is in hydraulic communication with this or these hollow conductors so that coolant flowing out of this or these hollow conductors can collect in the coolant passage, or coolant in the coolant passage can be introduced into this or these hollow conductors.

[0012] Due to its modular design, the connection device can be simply adapted to the predetermined requirements and configured with more or fewer electrical connection members according to the number of electrical phases of the electric machine. The components (connection members, seals, insulators) required for this only need to be integrated into the stacked structure.

[0013] The side member can in principle be any member provided on one side of the connection member and being part of the stacked structure. The side member can correspondingly be an insulator, a seal or other members. Other members, such as insulators and / or another seal, can be provided between the connection member and the side member.

[0014] The connection member is preferably made of a metallic material (such as copper). The internal coolant passage preferably extends in the metallic material.

[0015] The seal is preferably designed as a flat seal.

[0016] In a special embodiment of the present invention, the connection device is designed as a stacked structure, and its end faces are respectively closed by electrically insulating side members. At least one of the end face side members preferably has a central coolant interface through which coolant can enter the coolant passage or the coolant flowing out of the coolant passage can be discharged through this.

[0017] The stacking direction of the components of the connection device extends substantially along a straight line. With the help of wedge-shaped members, a curved (such as annular) or other geometrically shaped stacked structure can also be produced.

[0018] The components of the connection device, i.e., at least the connection member and the side member, are preferably designed as plate-shaped.

[0019] This or these hollow conductors connected to the connection member preferably point in one direction in their connection area, and the direction extends substantially transversely to the stacking direction (stacking direction) of the connection member and the side member. The hollow conductor joints are preferably all arranged on the same side of the stacked structure.

[0020] In a special embodiment, the connection device includes at least one conductive connection member and a seal. The internal coolant passage preferably extends through the connection member and the seal in this case.

[0021] In a multiphase embodiment of the connecting device, the connecting device correspondingly includes a plurality of connecting members arranged side by side, wherein at least one seal or insulator is respectively provided between two adjacent connecting members. In a special embodiment of the present invention, for example, at least one seal and insulator can be provided between two adjacent connecting members. Therefore, the multiphase embodiment of the connecting device includes a plurality of connecting members arranged side by side, a plurality of seals, and optionally a plurality of side members.

[0022] The connecting member preferably has components for connecting electrical phases (U, V, W), such as terminal blocks, cable joints, etc.

[0023] In a special embodiment, the connecting device has at least two integrated coolant channels through which coolant can enter the hollow conductor or collect the coolant flowing out of the hollow conductor.

[0024] The connecting device can also have a clamping device for clamping the connecting members, side members, and other stacked structural members included as the case may be to each other. In one embodiment of the present invention, the clamping device can include one or more clamping bolts extending through the connecting device. Alternatively, the clamping device can also clamp the stacked structure from the periphery in the form of a clamping member.

[0025] These stacked members of the connecting device can also be bonded to each other.

[0026] The present invention also relates to an electric motor having a hollow conductor winding and a connecting device for electrically and hydraulically connecting the hollow electric conductors designed in a stacked or laminated structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be explained in detail below with reference to the accompanying drawings, wherein:

[0028] Figure 1 A schematic diagram showing a three-phase motor with a hollow wire winding disclosed in the prior art;

[0029] Figure 2 Showing an embodiment of an electrical / hydraulic connecting device for a star-connected three-phase motor;

[0030] Figure 3 Showing Figure 2 A side view of a part of the electrical / hydraulic connecting device in ;

[0031] Figure 4 Showing a cross-sectional view of the electrical / hydraulic connecting device along the longitudinal axis of the connecting device;

[0032] Figure 5An embodiment of an electrical / hydraulic connection for a three-phase motor with star connection is shown, in which the part for the inflow and the part for the return flow of the cooling circuit are arranged spatially separated from each other;

[0033] Figure 6 An embodiment of an electrical / hydraulic connection for a three-phase motor connected in star connection is shown, in which the part for the cooling circuit feed flow and the part for the return flow are combined in one unit. DETAILED DESCRIPTION

[0034] Figure 1 A schematic diagram of a known three-phase synchronous motor 25 is shown, which has an inner stator 24 and an outer rotor (not shown). The electrical phases are labeled L1, L2, L3 or 0 and are connected in a star connection.

[0035] The stator 24 comprises six teeth 20 on which windings 18 are arranged. Each winding 18 is formed by a hollow conductor 17 through which a coolant flows in order to cool the motor 25 during operation. In the embodiment shown, the coolant enters the hollow conductor end of each winding 18 and the star point O, respectively, and is discharged through an internal T-shaped connector 26.

[0036] Figure 1 The synchronous machine shown also includes a cooling system, which has a coolant pump 21 and a heat exchanger 22. The pump 21 pumps the coolant through the coolant lines 19 to the phase ends of the winding 18 and the star point 0, from which the coolant enters the corresponding hollow conductor 17. The coolant then flows through the hollow conductors 17 and flows back to the heat exchanger 22 through the T-shaped connector 26, where it continues to flow to the pump 21 after being cooled.

[0037] In this motor, the electrical and hydraulic connection solutions for each hollow conductor 17 are relatively complex. Therefore, an alternative connection device with a stacked structure is proposed, as shown in the following figure. The connection device according to the invention can be applied in principle to all single-phase or multi-phase internally cooled motors, as well as other internally cooled devices, such as electromagnets, valves, etc.

[0038] Figure 2An electrical / hydraulic connection device 1 for a hollow conductor 17 of an internally cooled electric machine 25 according to a first embodiment of the present invention is shown. In this embodiment, the connection device 1 includes four connection members 2 arranged side by side, corresponding to the respective phases U, V, W, and the star point *, all made of a conductive material (such as copper). Each hollow conductor 17 is connected to the corresponding connection member both electrically and hydraulically. For this purpose, each connection member 2 includes a plurality of hollow conductor joints 6, and each hollow conductor joint connects an end of a hollow conductor. The end of the hollow conductor can be mounted on the connection member 2 by, for example, brazing, welding, or other means. Additionally, each connection member 2 includes a terminal 3, and each electrical phase (U, V, W, or *) can be connected to the terminal 3 through a cable joint.

[0039] A first seal 5, an insulator 4, and another seal 5 are respectively provided between two adjacent connection members 2. The seal 5 is preferably designed as a flat seal. Each of the two end faces (left and right sides in the figure) of the connection device 1 is provided with an electrically insulating side member 24, which forms the end closure of the device. Overall, a stacked structure or a laminated structure is formed.

[0040] In the embodiment shown here, the components 2, 4, 5, 24 of the stacked structure are clamped by a clamping device 11. Thereby, these components 2, 4, 5, 24 are pressed against each other, and at the same time, the sealing of the internally extending coolant channel 16 is achieved. Such a connection device 1 can be simply installed, and more or fewer connection members 2 can be configured according to the number of electrical phases of the electric machine 25 or the number of series joints to be connected. In addition to being used for phase connection, the connection member 2 can also achieve an electrical connection that conforms to a specific winding scheme. In order to reduce the hydraulic pressure required for the flow through the coil, the coil can also be divided, and the parts of the coil are electrically connected in the connection member 2. The parts of the coil are thus electrically connected in series, but the coolant can be supplied in parallel, thereby reducing the pressure required for the flow.

[0041] Figure 3 、 Figure 4 Subsequently, the internal structure of the connection device 1 and the clamping device 11 are shown in detail. Here, Figure 3 shown Figure 2 is a side view of a part of the electrical / hydraulic connection device 1, Figure 4 and shown Figure 3 is a sectional view of the connection device 1 along the longitudinal axis of the connection device. As Figure 4 shown, a first coolant channel 16 extends through the left part of the laminated structure and is hydraulically connected to the hollow conductor joints 6 of the connection members 2 of the phases U, V, W. Another coolant channel 16 extends through the right part of the connection device 1 and is hydraulically connected to the hollow conductor joints 6 of the connection member 2 of the star point *. Each of the side members 24 arranged at the ends includes a central coolant interface 8, through which coolant can enter the coolant channel 16 or the coolant flowing out of the coolant channel 16 can be discharged (see arrows VL, RL).

[0042] In the mode of operation of the cooling cycle shown here, Figure 4 the left coolant connection 8 shown is used as the coolant inlet (inflow), and the right coolant connection 8 is used as the coolant outlet (return flow). The left coolant channel 16 is thus the diversion channel 9 through which the coolant enters each hollow conductor 17 (see the outward arrows at the ends of the hollow conductors 17). The right coolant channel 16 is thus the collection channel 10 in which the coolant flowing out of each hollow conductor 17 is collected (see the inward arrows at the ends of the star-point hollow conductors).

[0043] In this embodiment, the clamping device 11 includes three clamping bolts 12 or screws that extend through the entire connecting device 2. The protruding ends of the clamping bolts 12 are provided with nuts 13 by means of which the device is clamped.

[0044] Figure 5 An embodiment of an electrical / hydraulic connecting device 1 for a star-connected three-phase motor 25 is shown, in which the part of the connecting device 1 designed for the inflow of the cooling circuit and the part for the return flow are arranged spatially separated from each other. In this case, the left part includes the connectors 2 for all three phases U, V, W, and the right part includes only one connector 2 for the star point. The division of the connecting device can also be achieved in other ways.

[0045] Figure 6 A further embodiment of an electrical / hydraulic connecting device 1 for a star-connected three-phase motor 25 is shown, in which the part designed for the inflow of the cooling circuit and the part for the return flow are combined in a single unit.

Claims

1. A connecting device (1) for electrically and hydraulically connecting a hollow electrical conductor (17) of an internally cooled electrical device, in particular an electric motor (23), comprising: --At least one electrically conductive connecting member (2) having one or more hollow conductor joints (6) for connecting the ends of one or more hollow conductors (17); --At least one electrically insulating side member (24) provided on one side of the connecting member (2), wherein the at least one connecting member (2) and the at least one side member (24) are arranged in a stack, characterized in that, at least two coolant channels (16) are integrated in the stack, through which coolant can enter the hollow conductor (17) or can collect the coolant flowing out of the hollow conductor (17).

2. The connecting device (1) according to claim 1, characterized in that, The hollow conductor (17) is connected to the connecting member (2) in a direction that is substantially transverse to the stacking direction of the connecting member (2) and the side member (24).

3. The connecting device (1) according to claim 1, characterized in that, The internal coolant channels (16) extend substantially in the stacking direction of the connecting member (2) and the side member (24).

4. The connecting device (1) according to claim 1, characterized in that, The connecting device includes a plurality of connecting members (2) arranged side by side, and at least one seal (5) is provided between every two adjacent connecting members (2).

5. The connecting device (1) according to claim 1, characterized in that, The connecting device forms a stacked structure that extends substantially along a straight axis.

6. The connecting device (1) according to claim 1, characterized in that, The connecting device forms a stacked structure that is respectively closed by electrically insulating side members (24) at its end faces.

7. The connecting device (1) according to claim 6, characterized in that, At least one of the side members (24) is provided with a central coolant joint (8) through which coolant can enter the coolant channel (16) or can discharge the coolant flowing out of the coolant channel (16).

8. The connecting device (1) according to claim 1, characterized in that, A clamping device (11) is provided for clamping the connecting member (2) and the side member (24) and optionally other components of the stacked structure to each other.

9. The connecting device (1) according to claim 1, characterized in that, The connecting member (2) has means (3) for connecting electrical phases (U, V, W).

10. The connecting device (1) according to claim 8, characterized in that, The clamping device (11) includes a clamping bolt (12) that extends through the connecting device (2).

11. An internally cooled electrical device, in particular an electric motor, having a hollow conductor winding (18) and a connecting device (1) according to one of the preceding claims for electrically and hydraulically connecting the hollow electrical conductor (17).

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