Electric motor

Abstract

The invention relates to an electric motor, in particular for a gas delivery device, comprising a stator (28) and a rotor (26) surrounded by the stator (28), the stator (28) having stator segments (34, 35, 38) with stator windings (36). An electrical insulation (40; 40 ') is provided between the stator winding (36) and the rotor (26). 50) comprising at least a potting material (50). According to the invention, the electrical insulation additionally comprises at least one insulation element (40) which covers the stator winding (36) at least in some regions and which is made of a material having a higher elasticity than the potting material (50).

Description

Technical Field

[0001] The invention relates to an electric motor according to the preamble of claim 1 . Background Art

[0002] From DE 10 2018 201 162 A1, an electric motor is known for driving a gas delivery device in the form of an air compressor for a fuel cell system. The air compressor has a compressor wheel connected to a rotor, wherein the rotor is driven by the electric motor. The electric motor has a stator surrounding the rotor, wherein the stator includes a stator section with a stator winding. An electrical insulation portion is provided between the stator winding and the rotor, which is implemented, for example, as a potting mass. The potting mass is applied in a liquid or plastic state and then solidified. After solidification, the potting mass becomes brittle and cracks may occur therein, especially after the electric motor has been running for a long time, due to the temperature changes that occur, so that the electrical insulation may no longer be fully guaranteed. Summary of the invention

[0003] In contrast, the electric motor according to the invention has the advantage that sufficient electrical insulation is ensured over a long operating period by the at least one insulating element, since no cracks can form in the insulating element due to its elastic deformability.

[0004] Advantageous embodiments and developments of the invention are given in the dependent claims. The insulating effect of the insulating element is further increased by the configuration according to claim 2 or 3. A sufficient contact of the insulating element on the stator winding is achieved by the configuration according to claim 4 or 5. The adhesion of the potting material on the insulating element is improved by the configuration according to claim 7. The positioning of the at least one sensor can be achieved in a simple manner by the configuration according to claim 8 or 9, without the need for further components.

[0005] Further advantages, features and details of the invention emerge from the following description, in which various exemplary embodiments are described in detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] It shows:

[0007] Figure 1 Schematic diagram of a fuel cell system having a gas delivery device implemented as an air compressor;

[0008] Figure 2 In longitudinal section Figure 1 an enlarged view of a detail of the air compressor in the area of ​​the electric motor with at least one insulating element;

[0009] Figure 3 an insulating element before it is arranged in the electric motor; and

[0010] Figure 4 An insulating element in longitudinal section with a sensor arranged in a receptacle formed in the insulating element. DETAILED DESCRIPTION

[0011] exist Figure 1 In the figure, a fuel cell system, for example for a motor vehicle, is shown in a simplified schematic diagram. The fuel cell system has at least one fuel cell stack 10, which is supplied with fuel, for example hydrogen, via an anode system 12 and with an oxidant, in particular air, via a cathode system 14. The cathode system 14 has a gas delivery device 16 in the form of an air compressor, via which the fuel cell stack is supplied with air of the required amount and pressure for the respective operating state. Figure 2 As shown in FIG. 1 , the air compressor 16 has a multi-part housing 18, in which an electric motor 20 is arranged as a drive device, by which a shaft 22 is driven to rotate about its longitudinal axis 23, and at least one compressor wheel 24 is connected to the shaft. The shaft 22 is connected to a rotor 26 of the electric motor 20, or the rotor 26 is part of the shaft 22. The electric motor 20 also has a stator 28 surrounding the rotor 26.

[0012] The stator 28 is arranged in the housing 18 and can be surrounded by a cooling jacket 30. The stator 28 has a stator base body 32, which can be composed of a plurality of stator sheets assembled into a package. A stator winding 36 is arranged at least on a stator section 34 of the stator base body 32, which is located in the middle in the direction of the longitudinal axis 23 of the shaft 22. The stator winding 36 extends along the longitudinal axis 23 between two opposite ends of the stator. At the ends, the stator winding 36 protrudes beyond the stator base body 32 in the longitudinal direction and forms so-called winding heads 38. In the region of these winding heads 38, each stator winding 36 extends transversely to the longitudinal axis 23 of the stator 28 and approximately in its circumferential direction. In the region of the winding heads 38, the stator 28 has a larger inner diameter than in the central stator section 34. The stator 28 has a transition section 35 which is at least approximately conical between the central stator section 34 and the winding head 38. The central stator section 34 forms a first stator section with a small first inner diameter and the winding head 38 forms a second stator section with a larger inner diameter.

[0013] The rotor 26 is arranged in the stator 28 at a small radial distance from the stator winding 36, and an electrical insulation is arranged between the stator winding 36 and the rotor 26. The electrical insulation has at least one insulating element 40 (to be explained in more detail below) and a potting material 50. Figure 2 and Figure 3 Detailed Description of the Insulating Element 40 in accordance with a first embodiment is shown.

[0014] The insulating element 40 is made of an electrically insulating material, in particular plastic, which has a higher elasticity than the potting material 50. The at least one insulating element 40 is designed so that it at least partially covers the stator winding 36. The insulating element 40 is preferably designed as an at least approximately closed ring around the rotation axis 23 of the rotor 26. The insulating element 40 extends at least over a part of the stator winding 36, as seen in the direction of the rotation axis 23. Preferably, the at least one insulating element 40 rests on the stator winding 36 in a radial direction relative to the rotation axis 23 and fixes the stator winding on the stator base body 32 before the potting material 50 is introduced.

[0015] The insulating element 40 is constructed corresponding to the inner contour of the stator 28 and has: a first section 42 with a small outer diameter, which is arranged in the middle stator section 34; a second section 44 with a larger outer diameter, which is arranged in the region of the winding head 38; and an at least approximately conical transition section 46, which is arranged in the region of the transition section 35 of the stator 28.

[0016] It may be provided that the insulation element 40 is arranged only on one side of the stator 28. Alternatively, an insulation element 40 may be arranged on both sides of the stator 28, wherein the insulation elements 40 on both sides are preferably designed identically.

[0017] The insulation element 40 is inserted into the stator 28 from the side of the winding head 38. Next, a potting material 50 is introduced, which fills the existing cavity between the insulation element 40 and the stator winding 36 and also covers the inner side 41 of the insulation element 40 facing away from the stator winding 36. The inner side 41 of the insulation element 40 can have a surface with a high degree of roughness, so that the adhesion of the potting material 50 is improved.

[0018] exist Figure 4 2 shows an insulating element 40 according to a second exemplary embodiment. The insulating element 40 is designed essentially the same as in the first exemplary embodiment, but additionally has a receptacle 60 for a sensor 62, for example a temperature sensor. The receptacle 60 is designed, for example, as a groove-shaped recess or depression in the circumference of the insulating element 40, which extends from the end of the insulating element 40 pointing toward the stator 28 into the second section 44 of the insulating element. After the insulating element 40 has been inserted into the stator 28, the sensor 62 can be pushed into the receptacle 60.

[0019] The sensor 62 is preferably used to detect the temperature of the stator winding 36, in particular in the region of the winding head 38. In order to ensure good contact between the sensor 62 and the stator winding 36, it can be provided that at least one spring-loaded arm is arranged on the insulating element 40, which acts on the sensor 62 and presses it against the stator winding 36.

Claims

1. An electric motor, in particular for a gas conveying device, comprising a stator (28) and a rotor (26) surrounded by the stator (28), wherein: The stator (28) has a stator segment (34, 35, 38) with a stator winding (36), wherein an electrical insulation (40; 50) is arranged between the stator winding (36) and the rotor (26), wherein the electrical insulation at least comprises a potting material (50), characterized in that the electrical insulation additionally comprises at least one insulating element (40), which at least partially covers the stator winding (36) and is made of a material with a higher elasticity than the potting material (50).

2. The electric motor according to claim 1, characterized in that The at least one insulation element (40) extends over at least a portion of the longitudinal extension of the stator winding (36), viewed in the direction of the axis of rotation (23) of the rotor (26).

3. The electric motor according to claim 1 or 2, characterized in that: The at least one insulation element (40) is designed as an at least approximately closed ring surrounding the axis of rotation (23) of the rotor (26).

4. The electric motor according to any one of claims 1 to 3, characterized in that The outer contour of the at least one insulating element (40) is designed to correspond to the inner contour of the stator (36).

5. The electric motor according to claim 4, characterized in that The stator (28) has at least two sections (34, 38) with different inner diameters, wherein a transition section (35) between the two sections (34, 38) is at least approximately conical in shape, and the at least one insulating element (40) correspondingly has two sections (42, 44) with different outer diameters and an at least approximately conical transition section (46) between them.

6. An electric motor according to any one of the preceding claims, characterized in that Before the potting material (50) is introduced, the stator winding (36) is at least partially fixed by the at least one insulating element (40).

7. An electric motor according to any one of the preceding claims, characterized in that The at least one insulation element (40) has a surface with a high degree of roughness on its inner side (41) facing away from the stator winding (36).

8. An electric motor according to any one of the preceding claims, characterized in that The at least one insulating element (40) has at least one receiving portion (60) for at least one sensor (62).

9. The electric motor according to claim 8, characterized in that The receptacle (60) is designed as a recess or depression in the at least one insulating element (40).

10. The electric motor according to claim 8 or 9, characterized in that: The sensor (62) is a temperature sensor, by means of which the temperature of the stator winding (36) is preferably detected.

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