CROSS-REFERENCES TO RELATED APPLICATIONS

This application is the U.S. National Stage of International Application No. PCT/EP2017/068365, filed Jul. 20, 2017, which designated the United States and has been published as International Publication No. WO 2008/031536 and which claims the priority of European Patent Application, Serial No. 16189489.4, filed Sep. 19, 2016, pursuant to 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The invention relates to a stator for an electric rotating machine.

The invention additionally relates to an electric rotating machine with at least one stator of this kind.

The invention further relates to a pod drive with at least one electric rotating machine of this kind.

The invention also relates to a ship with at least one pod drive of this kind.

The invention further relates to a method for manufacturing a stator of this kind.

A stator of this kind preferably occurs in an electric rotating machine, in particular in a motor or generator, which is employed in ship construction, and has a power consumption of at least of one megawatt.

The stator windings of an electric rotating machine of this kind are generally embodied as preformed coils, also known as bar coils. Preformed coils are for example manufactured by means of casting or powder metallurgy. A winding head, created through the bending at right angles of the conductors of the preformed coils is located on the ends of the preformed coils. This winding head requires a significant axial installation space. Ohmic losses, which reduce the efficiency of the electric rotating machine, occur through the additional inactive conductor length of the winding head. In addition it is necessary to cool the winding heads. Further installation space is required for cooling purposes.

Particularly in the case of fast-running low-pole machines, the increased bearing clearance resulting from the winding heads has a disadvantageous effect on the rotor dynamics. Furthermore, additional complex stiffening measures are required as a result of the great conductor lengths, in order to prevent impermissible oscillations and deformations during operation. In addition the overall length and the weight of the electric rotating machine increase. Particularly in the case of a modular structure of large machines, in which multiple sub-machines in the axial direction form a complete machine, significant electrically unused lengths arise as a result of the winding heads.

The patent specification DE 10 2009 032 882 B3 describes a method for manufacturing a preformed coil for a stepped winding of a dynamoelectric machine and a preformed coil manufactured by means of the method cited. In order to simplify the manufacture of the preformed coil, this is manufactured from a raw coil, wherein the raw coil has two longitudinal sides, which are provided to be inserted into slots of a stator or a rotor of the dynamoelectric machine. The raw coil has two winding head sides, which are provided in each case to form a winding head of the preformed coil, wherein the longitudinal sides are bent through 90° in such a way as to insert the longitudinal sides into the slots and offset the winding head sides from the longitudinal sides.

The published patent application DE 199 14 942 Al describes a method for manufacturing a stator winding for an electric machine and such a stator winding. The machine has pronounced poles. With their ends, coil conductors project over the laminated stator core in an axial direction and are fixed in module clamps. On the modules are located conducting tracks, which form the windings with the conductors or run from clamps to external attachment points.

Patent specification EP 1 742 330 B1 describes a stator winding head for a stator part of a turbo generator. The stator winding head is in the form a disk with a central outlet for the passage of a rotor, wherein the disk has an insulating main body, in which is integrated an electrical connection for contacting a stator conductor. The contact is manufactured in the form of a plug connection and/or with through-connections.

The published patent application DE 10 2014 207 621 Al discloses a stator of an electric rotating machine, comprising a laminated stator core with multiple slits, a segmented winding with multiple phases and multiple base plates, which are laminated on each end of the laminated stator core in an axial direction. The laminated stator core and multiple winding bars of the segmented winding form a laminated stator core arrangement. The multiple base plates and multiple winding edge connectors of the segmented winding form multiple baseplate arrangements. The stator is configured by the laminated stator core arrangement and the multiple baseplate arrangements, which are laminated on each end of the laminated stator core arrangement.

Patent specification U.S. Pat. No. 5,623,178 A describes a multiphase motor, which has molded coil parts, which are separately inserted into a slot. The molded coil parts are connected to molded coil pieces of a further slot of the same phase via a connecting element. The connecting element has conductive elements, which are laminated in a direction perpendicular to a rotating shaft of the rotor in the motor via insulating layers. The molded coil parts are separately connected to each other by these conductive elements, by means of which the protrusion of a coil end from each slot is reduced, enabling the miniaturization and weight reduction of the motor. The dimensional precision of the connecting elements can furthermore be improved by means of a simple construction and manufacturing method, by way of which the properties of the electric motor can be significantly improved.

The published patent application US 2004/0100157 Al describes an electric motor with a rotor and a stator, wherein the stator has a multiplicity of stator slots, which face the rotor. Stator cons are held in the multiplicity of stator slots. The stator coils comprise a multiplicity of bars, which are positioned within the stator slots, wherein each of the bars has at least one end which projects from one of the multiple stator slots. At least one end cap is arranged on the stator, wherein the at least one end cap has a multiplicity of jumpers. Each jumper has two connection channels, wherein each connection channel ends in an opening. The end cap arranged on the stator in such a way that ends of the multiplicity of bars, which project from the stator slots, are accommodated by the connection channels of the multiplicity of jumpers.

The invention is based on the object of providing a stator for an electric rotating machine, which with a minimal axial length, has improved electrical and thermal properties compared with the prior art.

SUMMARY OF THE INVENTION

According to the invention the object is achieved by a stator for an electric rotating machine, which has a laminated stator core with coil bars and at least one stator winding head board with an insulating main body, wherein the coil bars in each case have multiple subconductors, wherein conducting tracks are integrated into the insulating main body, wherein the at least one stator winding head board abuts an end face of the laminated stator core, wherein the conducting tracks are connected to the subconductors of the coil bars in a firmly bonded manner and wherein each subconductor is in each case connected to at least one separate conducting track.

According to the invention the object is also achieved by an electric rotating machine which has at least one stator of this kind.

According to the invention the object is further achieved by a pod drive with at least one electric rotating machine of this kind.

According to the invention the object is additionally achieved by a ship with at least one pod drive of this kind.

According to the invention the object is in addition achieved by a method for manufacturing a stator for an electric rotating machine, wherein the stator has a laminated stator core with coil bars and a stator winding head board with an insulating main body, wherein the coil bars in each case have multiple subconductors, wherein conducting tracks are integrated into the insulating main body, wherein the at least one stator winding head board is abutted to an end face of the laminated stator core, wherein the conducting tracks are connected in a firmly bonded manner to the subconductors of the coil bars and wherein each subconductor is connected in each case to at least one separate conducting track.

The advantages and preferred embodiments listed below in relation to the stator can be transferred analogously to the electric rotating machine, the pod drive, the ship and the manufacturing method.

The invention is based on the idea of reducing the axial length of the stator of an electric rotating machine with an output of at least one megawatt by redesigning the winding heads, which as a rule require a substantial axial installation space. While the windings in the area of the laminated stator core, which are located in particular in slots, continue to be embodied in their conventional form as coil bars, the winding heads are embodied as a stator winding head board, in which run conducting tracks which connect the respective coil bars to each other. The conducting tracks of the stator winding head board are surrounded by an insulating main body, which replaces the insulation of the conductors in the area of the winding heads. The winding head board abuts the laminated stator core, in particular directly and over its full area, so that at least part of the heat dissipation of the conducting tracks takes place via the laminated stator core, in particular if the insulating main body has a high level of thermal conductivity. Through the use of a stator winding head board of this kind the axial length of the stator is significantly shortened, and lower ohmic losses occur in the area of the winding heads. Here the coil bars are connected to the conducting tracks in a firmly bonded manner. For example the conducting tracks are welded or soldered to the coil bars. A firmly bonded connection saves a great deal of space, and requires no additional connecting elements. Accordingly the stator as a whole has a very minimal axial length.

The coil bars in each case have multiple subconductors, wherein each of the subconductors is connected in each case to at least one separate conducting track. At least one separate conducting track is thus assigned to each subconductor, so that the subconductors are routed individually through the insulating main body of the winding head board. As a result of the current deflection arising, the electrical resistance is reduced, and less heat loss needs to be dissipated. Furthermore, the surface of the individual subconductors, which is in direct contact with the insulating main body, is larger compared to a complete conductor, so that the heat dissipation in the area of the winding head board is further optimized. The smaller conducting track diameter of the individual subconductors gives rise to greater flexibility in the conducting track routing in the winding head board.

The firmly bonded connection is advantageously embodied as a welded connection. The coil bars are flat welded to the conducting tracks, in particular by means of laser welding, A welded connection saves space, and high forces and torques can be transmitted.

In one preferred embodiment, the stator winding head board is embodied in a multilayer fashion. A multilayer stator winding head board has multiple laminations of at least one insulating material, wherein the conducting tracks run in at least one lamination. By means of a multilayer stator winding head board it is possible to optimize the electrical, mechanical and thermal properties of the stator winding head board with respect to a minimal axial length and an efficient heat dissipation.

In a particularly advantageous manner, the multilayer stator winding head board comprises at least two layers arranged one on top of the other, which in each case have at least one conducting track. The routing of conducting track layers arranged one above the other can be realized in a flexible and space-saving manner.

In a further preferred embodiment the thickness of the conducting tracks amounts to at least several millimeters, in particular at least 3 millimeters, and a maximum of a few centimeters, in particular a maximum of 3 centimeters. By means of a conducting track thickness of this kind a high current load capacity is achieved and the ohmic losses are very low.

In a further advantageous embodiment the stator winding head board is connected to the laminated stator core by means of connecting elements, in particular bolts. A connection of this kind is proven and reliable.

In an advantageous manner, the connecting elements run through the laminated stator core in an axial direction. The connecting elements additionally for example hold the laminated stator core together, so that no additional bolts are required, thereby saving installation space and the cost of further connecting elements.

In one advantageous embodiment the stator winding head board is embodied as a pressure plate. The laminates of the laminated stator core are held together by pressure plates arranged at both axial ends of the laminated stator core. In particular, at least one pressure plate of the laminated stator core is replaced by a stator winding head board, so that overall axial installation space is saved.

Advantageously, the conducting tracks are in thermally conductive connection with the laminated stator core. In particular, the thermally conductive connection is created in a planar manner over the insulating main body. At least part of the heat dissipation of the conducting tracks thus takes place via the laminated stator core.

Advantageously, the insulating main body contains a ceramic material. In particular, the insulating main body consists at least in part of at least one ceramic material or a plastic, having portions of at least one ceramic material. Ceramic materials, such as for example aluminum oxide, beryllium oxide or silicon carbide, possess very good insulating properties, great robustness and good thermal conductivity, for example of at least 5 Wm-1K−1. In particular, the thermal conductivity of the ceramic material enables an at least partial heat dissipation of the conducting tracks via the laminated stator core, by means of which in particular fewer resources are required for cooling purposes in the stator winding head, and the installation space necessary for the stator winding head board is reduced, in particular in an axial direction. Furthermore, the very good insulating properties of the ceramic material enable a more compact arrangement of the conducting tracks, leading to an additional reduction of the necessary installation space of the stator winding head board.

Expediently, the insulating main body contains aluminum oxide. In particular, the insulating main body comprises at least 96% aluminum oxide or a plastic, having a proportion of aluminum oxide. As well as possessing high thermal conductivity and very good insulating properties, aluminum oxide is also comparatively low in cost.

In a further advantageous embodiment, the stator winding head board is manufactured at least partially with an additive manufacturing method. Additive manufacturing methods are for example 3D printing and screen printing. For example the insulating main body is manufactured with a 3D-printing method or a screen-printing method and the conducting tracks subsequently cast, for example with a die casting procedure. Alternatively, the conducting tracks are manufactured using a 3D printing or a screen-printing procedure. The insulating main body is then applied, for example by means of sintering. An additive manufacturing method enables the realization of complex and compact structures, resulting in a reduction in the size of the stator winding head board.

In one advantageous embodiment, the electric rotating machine has at least one stator of this kind. Particularly with the use of two or more stators on one shaft of the electric rotating machine, the axial length of the electric rotating machine is reduced through the use of stator winding head boards.

In a further advantageous embodiment, the stator winding head board has at least one spacer, via which the stator winding head board abuts the laminated stator core. The at least one spacer is, for example, manufactured from plastic or metal and matched in its form to that of the end faces of the laminated stator core. Alternatively, multiple spacers of, in particular, the same height are used, which are, for example, arranged in the circumferential direction on the end faces of the laminated stator core. The contact between the stator winding head board and the laminated stator core is improved by means of the spacers.

