Electrical machine, coil assembly for an electrical machine, and method for producing said coil assembly

Abstract

A coil assembly (11) for an electrical machine has a coil former (12) composed of an electrically non-conductive material and a coil (13) held by the coil former (12) is composed of an electrically conductive material. The coil former (12) is produced from a ceramic material, the coil (13) is in the form of a coil molding.

Claims

1. A coil assembly for an electrical machine, comprising a coil former made of an electrically non-conductive ceramic material and including a hollow tubular main body and spaced apart webs projecting radially out from the main body so that outwardly open radially extending spaces are defined between the webs and outward of the main body; and a coil radially out from the main body of the coil former and held in the radially extending spaces between the webs of the coil former, the coil being made of an electrically conductive metal material in the form of a non-stranded coil molding so that the coil completely fills the radially extending spaces between the webs of the coil former and is coupled thermally to the core and the webs of the coil former.

2. The coil assembly of claim 1, wherein the coil former is produced from a ceramic sintered material.

3. The coil assembly of claim 2, wherein the coil is produced from an aluminum material or from a copper material.

4. The coil assembly of claim 1, wherein the webs of the coil former are inserted into the main body and form partition elements between matrices of the conductive metal material molded into the radially extending spaces between the webs to define the coil turns of the coil.

5. The coil assembly of claim 1, wherein the webs of the coil former are integral with the main body of the coil former.

6. An electrical machine comprising at least one rotor-end magnet and the coil assembly of claim 1.

7. The electrical machine of claim 6, wherein the coil former of the coil assembly has a recess inward of the main body, and the electrical machine further has a stator-end support with a projection inserted into the recess in the coil former so that the coil assembly is mounted onto the stator-end support.

8. The electrical machine of claim 7, wherein the projection of the stator-end support projects into the recess in the coil former, so that the coil assembly circumferentially surrounds the projection of the stator-end support.

9. The electrical machine of claim 8, wherein at least the projection of the stator-end support is produced from an iron material.

10. The coil assemble of claim 2, wherein the ceramic sintered material is a ceramic aluminum oxide material or a ceramic aluminum nitride material or a ceramic silicon nitride material.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a schematic detail of an electrical machine according in the region of a coil assembly according to the invention.

DETAILED DESCRIPTION

(2) The invention relates to a coil assembly for an electrical machine, to a method for producing the coil assembly, and to an electrical machine comprising the coil. The invention preferably is used in electrical machines that provide drive power in hybrid vehicles or electric vehicles.

(3) An electrical machine of the invention may be a synchronous machine with permanent-magnet excitation or external excitation, or an asynchronous machine with magnetic-field generation by electrically conductive coils positioned on an iron core. Although the invention preferably is used in electrical machines of this kind, it is also possible to use the invention in other electrical machines.

(4) FIG. 1 shows a highly schematic detail of an electrical machine in the form of a synchronous machine with permanent-magnet excitation, in the region of a stator-end support 10 and of a coil assembly 11 positioned on the stator-end support 10.

(5) The stator-end support 10 of the synchronous machine is a support composed of an iron material and may be called an iron core. The stator-end support 10 and the coil assembly 11 of FIG. 1 are stator-end assemblies of the electrical synchronous machine that interact with rotor-end magnets, not shown.

(6) A coil assembly 11 according to the invention has a coil former 12 composed of an electrically non-conductive material and also has a coil 13 held by the coil former 12 and composed of an electrically conductive material.

(7) The coil former 12 of the coil assembly 11 is produced from a ceramic material, preferably a ceramic sintered material, such as a ceramic aluminum oxide, a ceramic aluminum nitrite or a ceramic silicon nitrite. The coil 13 is produced from a metal material, such as an aluminum alloy or a copper alloy. The coil 13 is a coil molding, and hence is produced by a molding process.

(8) The use of a metal coil 13 in the form of a coil molding in combination with a coil former 12 composed of a ceramic material provides a particularly high power yield and therefore a particularly high degree of efficiency for the coil assembly 11 or an electrical machine with at least one coil assembly 11 of this kind.

(9) Therefore, the combination of the metal coil 13 in the form of a coil molding and the coil former 12 composed of a ceramic material enables optimal removal of heat from the coil 13 of the coil assembly 11 in the direction of the stator-end support 10 of the electrical machine.

(10) Coils 13 that have been produced by molding are thermally coupled to the material of the coil former 12 in an optimum manner. A ceramic material of the coil former 12 has a high degree of thermal conductivity and accordingly can dissipate heat produced in the region of the coil 13 in an optimum manner.

(11) The coil 13 preferably is molded onto or molded into the coil former 12. Accordingly the coil former 12 composed of the ceramic material is used as at least as part of a mold that is required to produce the coil 13 by molding. According to this advantageous development, the coil 13 is molded into the coil former 12 composed of the ceramic material or is molded onto the coil former, so that the coil 13 does not need to be de-molded from the coil former 12, which serves as a mold, but rather at least one part of the mold that is required for molding the coil 13 forms an integral constituent part of the coil assembly 11.

(12) According to a first variant of the invention, it is possible to use an integral coil former 12 composed of a ceramic material.

(13) The coil former 12 of the respective coil assembly 11 may be of multipartite design and may comprise a main body 14 and a plurality of webs 15. The webs 15 form electrically insulating partition elements for coil turns 18 of the coil 13, and are produced as separate assemblies from a ceramic material. The webs 15 preferably are inserted into slots in the main body 14 of the coil former 12. The main body is produced separately from a ceramic material. As a result, it is possible to form thin partition elements between the coil turns of the molded coil 13. The main body 14 with the webs 15 inserted into the slots in the main body 14 forms an inner part of a mold for the coil 13 that is to be produced by molding. The inner part of the mold is surrounded radially on the outside by an outer part of the mold.

(14) The webs 15 in the main body 14 of the coil former 12 are held by the outer part of the mold before the coil 13 is molded. To mold the coil 13, this mold is filled with the metal material of the coil 13. The outer part of the mold is removed after the material has hardened. The coil 13 that has been produced by molding connects the webs 15 to the main body 14 of the coil former 12. The main body 14 and the webs 15 that form the inner part of the mold are integral constituent parts of the coil assembly 11 produced in this way. De-molding the coil 13 from the inner part of the mold is dispensed with, and instead the coil assembly 11 produced in this way comprises the coil former 12 and the coil 13 mounted on the stator-end support 10 by the coil former 12.

(15) The coil assembly 11 preferably is mounted on the stator-end support 10 so that the coil former 12 of the coil assembly 11 has a recess 16 into which a projection 17 of the stator-end support 10 is introduced.

(16) The coil assembly 11 accordingly is fit onto the stator-end support 10 or mounted on said stator-end support. The projection 17 of the stator-end support 10 engages into the recess 16 in the coil former 12. In the process, the coil assembly 11 circumferentially surrounds the projection 17 of the stator-end support 10 on the outside.

(17) Accordingly, to produce a coil assembly 11, an integral or multipartite coil former 12 initially is provided and is composed of a ceramic material, preferably a ceramic sintered material comprising aluminum oxide or aluminum nitrite or silicon nitrite.

(18) This coil former 12 is used as at least part of a mold. The coil 13 is composed of the metal material that is molded onto the coil former 12 or is molded into said coil former. The coil former 12 forms an inner shell or an inner part of a multipartite mold. An outer shell or an outer part of the mold can be removed and reused after the coil assembly 11 has been molded.

(19) The present invention accordingly covers the use of a coil former 12 composed of a ceramic material in the case of a coil assembly 11 of an electrical machine. The coil 13 is composed of the metal material in the form of a coil molding and the coil former 12 is a constituent part of a mold for molding the coil 13. This ensures optimum connection of the metal material of the coil 13 to the ceramic material of the coil former 12, as a result of which heat that is produced in the region of the coil 13 can be dissipated in an optimum manner during operation.

(20) This ensures a high electrical power throughput by the respective coil assembly 11 and therefore ultimately by the electrical machine, as a result of which a high degree of efficiency of the electrical machine can be realized.

(21) Furthermore, the individual coil turns 18 of the coil 13 can be electrically insulated from one another in an optimum manner by the ceramic material of the coil former 12.