Structure-borne-sound-insulated electric motor

Abstract

The invention relates to an electric motor comprising a motor housing (1) and a stator (3) arranged in the motor housing (1), wherein an insulation element (2) is arranged between the stator (3) and housing (1), wherein the insulation element (2) consists of a composite material that is formed from at least two different materials.

Description

[0001] Structure-borne sound-insulated electric motor

[0002] The invention relates to a structure-borne sound-insulated electric motor, in particular for the electric drive of an electric vehicle (BEV).

[0003] Vibrations occurring in the electric motor, particularly those caused or transmitted by structure-borne noise, shorten its life expectancy and at the same time reduce the efficiency and increase the temperature of the system.

[0004] DE 10 2015 001 447 A1 proposes the use of a decoupling ring to provide an acoustically improved coupling between the stator and the motor housing of an electric motor. The parallelogram-shaped design of the decoupling ring's recesses and the angled configuration of the webs are intended to at least largely reduce the transmission of operational structure-borne noise from the motor components (stator, rotor) simply through their width and orientation.

[0005] The invention is therefore based on the object of providing structure-borne sound insulation in the electric motor that is improved compared to the prior art.

[0006] This problem is solved by an electric motor having the features of patent claim 1.

[0007] According to the invention, the electric motor comprises a motor housing and a stator arranged in the motor housing, wherein an insulating element is arranged between the stator and the housing, wherein the insulating element consists of a composite material which is formed by at least two different materials.

[0008] According to the invention, the composite material comprises at least one metal layer and at least one polymer layer bonded to the metal layer. In particular, the composite material comprises a metal layer and a polymer layer bonded to the metal layer. Alternatively, a second polymer layer can also be bonded to the metal layer, so that the metal layer acts as an intermediate layer and the two polymer layers act as cover layers. If the polymer layer has adhesive properties, the surface / surface of the stator in contact with the polymer layer and / or the surface / surface of the opening in the motor housing, in which the insulating element and the stator are accommodated, can be bonded or glued to the polymer layer.

[0009] The composite material exhibits structure-borne sound-damping properties. For the purposes of the invention, the damping is expressed by the so-called loss factor, which is determined according to DIN EN ISO 6721. According to the invention, the composite material exhibits a high loss factor over a broad temperature range, in particular a loss factor of 0.01 to 1.0 measured at 1000 Hz at temperatures between -10 and 100°C. Preferably, the composite material exhibits a loss factor of 0.05 to 0.5 measured at 1000 Hz at temperatures between -5 and 90°C, and more preferably a loss factor of 0.1 to 0.4 measured at 1000 Hz at temperatures between 10 and 65°C.

[0010] In contrast to the state of the art, the insulation element does not consist of a monolithic material, but combines at least two different materials, which can have a particularly beneficial effect on the structure-borne sound insulation in the electric motor and can promote or reduce it.

[0011] It goes without saying and is obvious to those skilled in the art that an electric motor also includes additional components such as a rotor, drive shaft, etc. Essential to the invention is the arrangement of a composite material between the motor housing and stator and the associated advantageous structure-borne sound insulation. Therefore, these additional components will not be discussed in detail. However, they are part of the electric motor and should be understood as such.

[0012] Advantageous embodiments and variants of the invention emerge from the dependent claims and the following description.

[0013] In one embodiment of the invention, the composite material is formed from a cylindrical slotted tube. The size or dimension of the slotted tube can be selected such that the entire stator can be surrounded or encased and can be simply slipped over the stator through the slot, which preferably extends parallel in the axial direction, and inserted together with the stator into the opening provided in the motor housing or can be pushed into the corresponding opening in the motor housing beforehand and the stator can then be inserted. In an alternative embodiment of the invention, the composite material is formed from a cylindrical closed tube. In this case, the size or dimensionThe dimensions of the closed tube must be selected in such a way that the tube is either previously placed on the stator and inserted together with it into the corresponding opening in the motor housing, or the closed tube is first placed in the opening and then the stator is inserted.

[0014] The composite material is, for example, formable, in particular deep-drawable and / or stretch-formable. For the purposes of the invention, formable, in particular deep-drawable and / or stretch-formable, means that these processes (i.e., forming, deep-drawing, stretch-forming) can be carried out without damaging the composite material, in particular without failure due to tearing or delamination.

[0015] Thus, the production of a cylindrical slotted tube from a flat material (semi-finished product), for example, can be achieved using a UO forming or a round rolling process. The production of a cylindrical (one-sided) closed tube from a flat material (semi-finished product, round blank), for example, can be achieved using deep drawing or flow-forming, with the base created by the forming process being separated after the forming process.

[0016] In one embodiment of the invention, the composite material comprises a first and a second metal layer with at least one polymer layer arranged between the first and the second metal layer.

[0017] In one embodiment of the invention, the metal layer of the composite material consists of a steel alloy or an aluminum alloy. Both steel and aluminum alloys can be made of common grades known to those skilled in the art that have good forming properties. A combination of a steel and an aluminum alloy is also conceivable if the composite material has a first and a second metal layer.

[0018] The metal layers can be the same or of different thicknesses.

[0019] The polymer layer has a particularly insulating effect and thus preferably provides electrically insulating properties. When a steel alloy is used as the metal layer, it can be provided with a corrosion protection layer on one or both sides, particularly one based on zinc and / or aluminum. If a corrosion protection layer is provided, the thickness can be between 0.5 and 20 μm.

[0020] In one embodiment of the invention, the metal layer has a thickness of at least 100 pm and a maximum of 1500 pm, in particular of at least 200 pm, preferably of at least 250 pm and preferably of at least 300 pm up to a maximum thickness of in particular a maximum of 1000 pm, preferably a maximum of 750 pm, preferably a maximum of 600 pm.

[0021] In one embodiment of the invention, the polymer layer is a viscoelastic adhesive. In particular, the adhesive is an acrylate-based adhesive.

[0022] In one embodiment of the invention, the polymer layer has a thickness of at least 20 pm to a maximum of 1500 pm, in particular at least 25 pm, preferably at least 40 pm to a maximum of 1000 pm, preferably a maximum of 500 pm, preferably a maximum of 250 pm, particularly preferably a maximum of 100 pm.

[0023] Another subject of the invention is an electrically driven vehicle or vehicle with hybrid drive, in particular a passenger vehicle, commercial vehicle, special vehicle, preferably a bus, a bus, a track-bound vehicle, preferably a tram or passenger-carrying wagon, containing an electric motor as described above.

[0024] The sole Figure 1 shows a roughly schematic representation of the components of an electric motor. In detail, the electric motor comprises a motor housing (1), a damping element (2), and a stator (3). Other components, such as a rotor, etc., which an operational electric motor requires, are not shown. The motor housing (1) has an opening (not shown) into which the stator (3) is inserted. A damping element (2), which is preferably designed as a cylindrically slotted or cylindrically closed tube, is arranged between the stator (3) and the motor housing (1).The insulating element (2) consists of a composite material which is formed from at least two different materials, wherein the composite material has at least one metal layer and at least one polymer layer bonded to the metal layer, preferably the composite material has a first and a second metal layer with at least one polymer layer arranged between the first and the second metal layer. Particularly preferably and not shown here, the composite material consists of two metal layers made of a steel alloy, each with a thickness of 600 μm, and an acrylate-based polymer layer with a thickness of 40 μm arranged therebetween. The composite material further preferably has a loss factor of 0.1 to 0.4 measured at 1000 Hz at temperatures of 10 to 65 °C.

Claims

Patent claims 1. Electric motor, comprising a motor housing (1) and a stator (3) arranged in the motor housing (1), wherein an insulating element (2) is arranged between the stator (3) and the motor housing (1), characterized in that the insulating element (2) consists of a composite material which is formed by at least two different materials, wherein the composite material has at least one metal layer and at least one polymer layer bonded to the metal layer, wherein the composite material has a loss factor of 0.01 to 1.0 measured at 1000 Hz at temperatures between -10 and 100 °C, determined according to DIN EN ISO 6721.

2. Electric motor according to claim 1, wherein the composite material is formed from a cylindrical slotted tube or from a cylindrical closed tube.

3. Electric motor according to one of the preceding claims, wherein the composite material comprises a first and a second metal layer with at least one polymer layer arranged between the first and the second metal layer.

4. Electric motor according to one of the preceding claims, wherein the metal layer consists of a steel alloy or an aluminum alloy.

5. Electric motor according to one of the preceding claims, wherein the metal layer has a thickness between 100 pm and 1000 pm.

6. Electric motor according to one of the preceding claims, wherein the polymer layer is a viscoelastic adhesive.

7. Electric motor according to one of the preceding claims, wherein the polymer layer has a thickness between 20 pm and 1500 pm.

8. Electrically powered vehicle comprising an electric motor according to one of the preceding claims.

9. A hybrid drive vehicle comprising an electric motor according to one of claims 1 to 7.

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