WO2007036505A1

WO2007036505A1 - Rotary electric motor

Info

Publication number: WO2007036505A1
Application number: PCT/EP2006/066694
Authority: WO
Inventors: Jürgen Huber
Original assignee: Siemens Aktiengesellschaft
Priority date: 2005-09-28
Filing date: 2006-09-25
Publication date: 2007-04-05

Abstract

Rotary electric motors have a stator fitted with windings and associated with a holding body and/or solid body made of metal, a thermal bridge being associated with at least one end winding of the stator windings and comprising a thermally conductive cast resin body in which the end winding is embedded. The surfaces of the holding body and/or solid body made of metal which face the cast resin body are joined thereto at least in part by a layer of a flexible, thermally conductive material. Also disclosed is the use of a rotary electric motor according to the invention for producing electric or mechanical energy.

Description

description

ROTATING ELECTRIC MACHINE

The present invention relates to rotary electric machines ^¬ Ma. More particularly, it relates to rotary electric Ma ^¬ machines with a provided with windings stator which a supporting body and / or a solid body are associated with metal, wherein at least one winding head of the stator windings is associated with a thermal bridge, which gene a wärmeleitfähi-, comprises the winding head embedding resin body , Furthermore, the invention relates to the use of a rotary electric machine according to the invention for the production of electrical or mechanical energy.

To avoid overheating in motors or generators, where due to their structural design special measures to dissipate the heat from the winding head areas of the support body of the stator are necessary, are used as thermal bridges often highly heat conductive Kunststof ^¬ fe.

For example, the German patent publication

DE 199 02 837 C1 (Siemens AG) a rotating electrical machine with a permanent-magnet rotor. Here, the tubular, highly thermally conductive support body of the stator forms a thermal bridge to a coolant. In order to effectively cool the winding heads of the stator windings, the winding heads are each assigned a thermal bridge, which completely fills the space between the winding heads and the supporting body of the stator. This thermal bridge is solid ^{ausgebil ¬} det and consists of a non-positively connected to the supporting body of the stator solid ring and cast in this cast resin body. The cast resin body has a thermal conductivity greater than 1.6 W / m K and ent ^¬ holds this purpose a powdered, highly thermally conductive filler in an amount of 50 to 90 wt .-%, preferably an aluminum nitride coated with silicon dioxide. In principle, however, can occur in rigid systems disadvantages. Due to the large differences in the expansion behavior of the components (metals, plastics), the temperature gradients occurring, the thermal cycling and mechanical stresses it often comes at the interfaces to the housing or the laminated core to forming columns or detachments. These worsen the heat transfer considerably. Especially with systems for the heat classes B, F, H and higher with continuous service temperatures of 130 ⁰ C, 155 ⁰ C, 180 ⁰ C and more, this problem occurs. In addition, these gaps or cracks make the entire system more susceptible to environmental influences such as moisture, aggressive media and dusts.

The aforementioned disadvantages of the prior art have not been satisfactorily solved. In particular, radial detachment of Gießharzkörpers are Bachten repeatedly to beo ^¬.

The object of the present invention has been found to overcome ^{¬ at} least one of the aforementioned disadvantages in the prior art. More particularly, the invention has provided the Aufga ^¬ be, a rotating electrical machine, bereitzustel ^¬ len with a provided with windings stator which a supporting body and / or a solid body are associated with metal, wherein at least one winding head of the stator windings is associated with a thermal bridge, which comprises a thermally conductive, the winding head embedding cast resin body, so that a detachment of Gießharzkörpers is avoided.

This object is achieved by a rotie ^¬- generating electrical machine with a versehe ^¬ winding stator, to which a supporting body and / or a solid body of metal are assigned, wherein at least one winding head of the stator windings is associated with a thermal bridge, which is a thermally conductive, the Winding head embedding cast resin body comprises, wherein those surfaces of the support body and / or the solid body made of metal, which are facing the casting resin body ^¬ , are connected to this at least partially by a layer of a flexible, thermally conductive material.

Rotary electrical machines in the sense of the invention may be electric motors or generators. You can also include a rotor next to the stator.

The supporting body of the stator carries this. It can completely or partially surround the stator and be connected to it in a force-fitting, positive-locking and / or material-locking manner.

The solid body of metal, which is associated with the stator, may be annular or take any other appropriate form. For example, it can be shaped irregularly to adapt to the structural conditions of the machine. The solid body may be mounted on the stator so that the stator windings pass through its end face. The solid body may consist of a

Consist of pieces or of several sheets. The division of the solid body into several sheets serves to reduce eddy current losses. Furthermore, such a lamination allows a fine adjustment of the contour of the solid body to the outer contour of the winding heads.

Cast resin body according to the invention refers to a body comprising casting resins on polyester, ester imide, silicone, polyurethane and epoxy base. Resins such as epoxy-based aromatic epoxy resins of bisphenol A and / or Bisphe ^¬ nol F have been found due to their balanced Eigenschaftspro ^¬ fils be particularly suitable. Thus, combinations of these aromatic epoxy resins with cycloaliphatic epoxy resins have an advantageous viscosity reduction.

The cast resin body may further comprise a filler which serves to increase the thermal conductivity. Particularly suitable in this case are ge ^¬ fillers, such as alumina, aluminum nitride, in particular coated aluminum nitride, silicon carbide and metal powder, in particular aluminum powder, and quartz flour and fused silica, and mixtures of these substances.

Thermal conductivity in the sense of the invention refers to the ability of a body to transport thermal energy in the form of heat. The thermal conductivity is expressed in units of watts per meter and Kelvin. The Wärmeleitfä ^¬ ability of Gießharzkörpers invention and the flexible, thermally conductive layer of the invention is in a range of> 0.1 W / m K to ≤ 500 W / m K.

Means flexible in the sense of the invention that the mate rial ^¬, expressed in megapascals, in egg nem range of> 1 MPa to ≤ 200 MPa, a modulus of elasticity.

The flexible, heat-conductive material according to the invention may be designed to be self-adhesive. As a result, it can be applied to the carrier body and / or to the solid body. The material may also be applied by methods such as spraying, gluing, brushing, casting or spin-coating.

The flexible, thermally conductive material according to the invention makes possible a permanent, preferably air-gap-free connection to the surfaces of the supporting body and / or the laminated core as well as to the surface of the cast resin body. It is thus possible to compensate for differences caused by differences in the expansion behavior of the individual components. As a result, delamination of the heat-conducting materials are avoided. The permanent gap-free connection of the interfaces minimizes the overall thermal resistance. This leads to a reduction of the maximum temperatures in the winding head area. As a result, a higher power utilization can be achieved because the efficiency is increased. Likewise, however, the reliability of the machine can be increased. This is however of importance ^¬ processing in machines that operate at elevated temperatures such as machines of thermal classes B (up to 130 ⁰ C), F (up to 155 ⁰ C), H (up to 200 ⁰ C) and above. This type of passive cooling also makes it possible to realize cost-effective and space-saving designs. Finally, a more effective protection against environmental influences such as moisture, aggressive Be ^¬ instincts and dusts is achieved.

In a preferred embodiment of the present invention, the elastic modulus of the flexible, heat-conductive layer is> 1 MPa to ≦ 200 MPa, preferably> 3 MPa to ≦ 150 MPa, more preferably> 5 MPa to ≦ 50 MPa. Thus, the flexible, heat-conductive layer according to the invention can also act as a damping element with regard to the mechanical vibrations that occur and reduce the mechanical wear of the machine by vibrations.

In a further preferred embodiment of the present invention, the thermal conductivity of the flexible, thermally conductive layer is> 0.1 W / m K to ≦ 500 W / m K, preferably> 0.2 W / m K to ≦ 200 W / m K, more preferably> 0.5 W / m K to ≤ 50 W / m K. This reduces stresses caused by differences in the temperature-dependent expansion behavior of the components of the machine, the temperature gradients that occur and the thermal cycling. Furthermore, a more efficient cooling of the machine is made possible by such a thermal conductivity.

In a further preferred embodiment of the present invention, the material of the flexible, thermally conductive layer is selected from the group comprising ethylene / propylene copolymer, ethylene / propylene / nonconjugated diene terpolymer, ethylene / vinyl acetate copolymer, unsaturated nitrile / conjugated Diene copolymer, hydrogenated unsaturated nitrile / conjugated diene copolymer, unsaturated nitrile / conjugated diene / ethylenically unsaturated monomer terpolymer, hydrogenated unsaturated nitrile / conjugated diene / ethylenically unsaturated monomer terpolymer, styrene / conjugated diene copolymer, hydrogenated styrenic rol / conjugated diene copolymer, polyisoprene, natural rubber, polyvinyl lybutadien, silicone rubber, epoxy resins, unsaturated Polyes ^¬ terharze (UP resins), polyurethane resins, acrylic resins, silicone resins and ^¬ / or Oxazoldinon-modified epoxy resins. Such materials are readily available and are characterized in that a suitable selection can be made for a specific application of the machine according to the invention. Depending on the configuration, the materials may be self-adhesive or adhere well to an adhesive.

In a further preferred embodiment of the present invention, the average thickness of the flexible, thermally conductive layer is> 0.1 mm to ≦ 10 mm, preferably> 0.3 mm to ≦ 7 mm, more preferably> 0.4 mm to ≦ 5 mm, even more preferably> 0.5 mm to ≤ 2 mm. The term "average Di ^¬ bridge" refers to the average of the measured layer thicknesses. This procedure can be bumps, depressions, etc. taken into account computationally. Can be reached with as clotting ^¬ according to material and cost that the thermal through the different expansion behavior of the Cast resin body and the surrounding components occurring voltages are reduced and so no separation of the layer occurs.

In a further preferred embodiment of the vorliegen- the invention, the flexible, thermally conductive layer to additionally ^¬ fibers, rigid fabric plies, flexible fabric inserts and / or fillers selected from the group comprising chalk, alumina and / or alumina trihydrate on. Such additives can help to better absorb the shear forces occurring in the layer. These additives can also be electrically conductive. As a result, damage points in the insulation of the stator windings can be revealed, for example, by the detection of leakage currents. Furthermore, the fillers can increase the thermal conductivity of the flexible, heat-conductive layer, without acting strongly abrasive. For example, the flexible, thermally conductive layer according to the invention may be a polyurethane resin which is filled with aluminum oxide trihydrate and has a density of> 1.35 to ≦ 1.40 g / cm ³ . Polyurethane resins are commercially well available, inexpensive, weather resistant and easily ver ^¬ workable. Aluminum oxide trihydrate as a filler increases the viscosity of the uncured resin, making it easier to apply even on non-planar surfaces. A polyurethane resin having a filler, which results in a density of> 1.35 to ≤ 1:40 g / cm ^3, showing a balanced and favorable profile of properties in terms of viscosity, Wär ^¬ meleitfähigkeit and abrasion. It is beneficial if the resin formulation is not highly abrasive, as processing by spraying from nozzles will be easier.

Furthermore, the flexible, heat-conductive layer according to the invention may have a modulus of elasticity of 21 MPa. Such layers have sufficient flexibility to reduce mechanical stresses caused by different expansion characteristics of the components of the rotating electrical machine. On the other hand, these layers are not as flexible as they formality in decreased stability ^¬ the component arrangement could result.

Likewise, the flexible, heat-conductive layer according to the invention may have a thermal conductivity of 0.5 W / m K. This ensures efficient cooling of the rotating electrical machine.

The thickness of the flexible, thermally conductive layer according to the invention may be in a range of> 0.9 mm to ≦ 1.2 mm. Such layer thicknesses can be easily realized by common application methods. A layer in said area has enough flexible material to absorb mechanical stresses.

Furthermore, the elongation at break of the flexible, heat-conductive layer according to the invention can be 70%. Such a high one Elongation at break is advantageous if the components of the rotating electrical machine are subjected to shear stresses, such as for example occur during operation of a vehicle NEN ^¬ Kgs.

Likewise, the glass transition temperature T _{g of} the flexible, thermally conductive layer 20 according to the invention may be ⁰ ° C. Thus, the layer at the operating temperatures of ro ^¬ tierenden electric machine on a rubber elastic behavior on th and can thereby reduce mechanical stresses and Vibratio ^¬ nen.

Below the glass transition temperature, the heat-conductive layer according to the invention may have an expansion coefficient of 55 ppm. Thus, although the layer is present in the ^energy-¬ elastic range, can still be reduced by cooling the rotary electric machine induced mechanical stresses. This is advantageous when the machine is in a cold medium, such as water, and is not operated continuously.

Above the glass transition temperature, the thermally conductive layer according to the invention may have an expansion coefficient of 150 ppm. When the layer is thus present in the rubber-elastic range, it can better reduce ^¬ voltages caused by differing ^¬ ches expansion behavior of the individual components of the rotary electric machine mechanical clamping.

In a further preferred embodiment of the present invention, the flexible, thermally conductive layer is disposed on the outer surface of an integrated insert and / or on the outer surface of the electrical conductor winding. In addition to improved heat dissipation, a pressure relief of the insert and / or the electrical conductor winding can be achieved as well when the Gießharzfüllkörper expands during heating. In a further preferred embodiment of the present invention, the casting resin in the cast-resin has a glass transition temperature of> -100 ⁰ C to ≤ 250 ⁰ C, preferably> -50 ⁰ C to ≤ 150 ⁰ C, more preferably> 0 ⁰ C to ≤ 100 ⁰ C. , even more preferably> 4 ⁰ C to ≤ 80 ⁰ C on. Casting resins with such glass transition temperatures have a favorable cracking behavior due to the easier removal of internal stresses, which counteracts material fatigue. Such glass transition temperatures also allow applications in cold water and at great depth, since water at 4 ⁰ C has the highest density ^¬ and therefore decreases in depth.

In a further preferred embodiment of the present invention, the support body is a housing comprising the stator. This constructive combination allows the

Heat, which is generated at the winding head of the stator, large and quickly forward to the environment.

The invention further relates to the use of a rotary electric machine according to the invention for obtaining electrical or mechanical energy. This is to be understood that the rotating electrical machine can be configured both as an electric motor and as a power generator and at the same time still the advantages of the inventively constructed devices for warming the winding heads of the stator can be used.

The object of the present invention will be explained in more detail with reference to the following Figures 1 and 2 and the embodiment 1.

Fig. 1 shows the winding head of the stator of an inventive ^¬ Shen electric motor.

Fig. 2 shows the winding head of the stator of an electric motor according to the invention ^¬ SEN with an additional coating on the winding. Fig. 1 shows the winding head of the stator of an inventive ^¬ Shen electric motor (1). A cast resin molding material (2) surrounds a winding (3) of a stator on the stator head. A flexible, heat-conductive layer (4) connects the casting resin molding material (2) and the solid body (5) or the housing (6) designed as a laminated core.

FIG. 2 shows a further winding head of the stator of an electric motor (7) ^{according to the} invention. A cast resin molding material (2) surrounds a winding (3) of a stator on the stator head. A flexible, thermally conductive layer (4) connects the cast resin ^¬ molding material (2) and designed as a laminated core Fest ^¬ material body (5) or the housing (6). Furthermore, the flexible, thermally conductive layer (4) partially envelops the winding (3) of a stator on the stator head.

Embodiment 1: flexible, thermally conductive layer

The methods of measurement used to explain the present invention are described below:

1. Modulus of elasticity: is determined as tensile modulus of elasticity according to ISO 527 and expressed in MPa. 2. Thermal conductivity: determined according to ISO 8894 and expressed in W / m K

3. Elongation at break: determined according to ISO 527 and expressed in%.

4. Glass transition temperature: determined according to ISO 6721 and expressed in ⁰ C

5. Coefficient of expansion: determined to ISO 11359 and expressed in parts per million (ppm).

Claims

claims

1. A rotating electric machine with a provided with windings stator, to which a supporting body and / or a solid are body-associated made of metal, wherein at least one Wi ckelkopf of the stator windings is associated ^¬ a thermal bridge comprising a thermally conductive, the winding head embedding cast resin, characterized in that the ^¬ those surfaces of the support body and / or the solid body made of metal, which are facing the Gießharzkörper, with this at least partially connected by a layer of a flexible, thermally conductive material.

2. Rotary electric machine according to claim 1, wherein the modulus of elasticity of the flexible, heat-conductive layer

> 1 MPa to ≤ 200 MPa, preferably> 3 MPa to ≤ 150 MPa, more preferably> 5 MPa to ≤ 50 MPa.

3. Rotary electric machine according to one of the preceding claims, wherein the thermal conductivity of the flexible, heat ^¬ conductive layer> 0.1 W / m K to ≤ 500 W / m K, preferably

> 0.2 W / m K to ≤ 200 W / m K, more preferably> 0.5 W / m K to ≤ 50 W / m K.

4. Rotary electrical machine according to one of the preceding claims ^¬, wherein the material of the flexible, thermally conductive layer is selected from the group comprising ethylene / propylene copolymer, ethylene / propylene / nonconjugated diene terpolymer, ethylene / vinyl acetate copolymer, unsaturated nitrile / conjugated diene copolymer, hydrogenated unsaturated nitrile / conjugated diene copolymer, unsaturated nitrile / conjugated diene / ethylenically unsaturated monomer terpolymer, hydrogenated unsaturated nitrile / conjugated diene / ethylenically unsaturated monomer terpolymer, styrene / conjugated diene copolymer , hydrogenated styrene / conjugated diene copolymer, polyisoprene, natural rubber, polybutadiene, silicone rubber, epoxy resins, unsaturated polyes- terharze (UP resins), polyurethane resins, acrylic resins, silicone ^¬ resins and / or oxazoledinone-modified epoxy resins.

5. Rotary electric machine according to one of the preceding claims, wherein the average thickness of the flexible, heat conductive layer> 0.1 mm to ≤ 10 mm, preferably> 0.3 mm to ≤ 7 mm, more preferably> 0.4 mm to ≤ 5 mm , more preferably> 0.5 mm to ≤ 2 mm.

6. A rotating electric machine claims to any of the preceding An ^¬, wherein the flexible, heat conductive layer zusätz ^¬ Lich fibers, rigid fabric plies, flexible fabric inserts and / or fillers selected from the group comprising Krei ^¬ de, alumina and / or alumina trihydrate having ,

7. A rotating electric machine according to claims one of the preceding An ^¬, wherein the flexible, thermally conductive layer on the outer surface of an integrated insert and / or assigns reasonable on the outer surface of the electrical conductor winding.

8. A rotating electric machine claims to any of the preceding An ^¬, wherein the casting resin in the cast-resin has a glass transition temperature of> -100 ⁰ C to ≤ 250 ⁰ C, preferably> -50 ⁰ C to ≤ 150 ⁰ C, more preferably> 0 ⁰ C to ≤ 100 ⁰ C, even more preferably> 4 ⁰ C to ≤ 80 ⁰ C.

9. A rotating electric machine according to claims one of the preceding An ^¬, wherein the supporting body is a comprehensive overall the stator housing.

10. Use of a rotary electric machine according to one of the preceding claims for the production of electrical or mechanical energy.