Electric machine for a motor vehicle

Abstract

The invention relates to an electric machine (10) for a motor vehicle, comprising a housing (12), a noise-insulating jacket (18) surrounding the housing (12), and at least one cooling channel (20) arranged radially between the noise-insulating jacket (18) and the housing (12) and through which a coolant can flow for cooling the electric machine (10), which is partially bounded by the housing (12) and partially by the noise-insulating jacket (18), wherein the cooling channel (20) has recesses (26) formed in an outer surface (22) of the housing (12) and elevations (28) formed in the outer surface (22) of the housing (12), wherein the noise-insulating jacket (18) comprises a heavy foil (30).

Description

[0001] The invention relates to an electric machine for a motor vehicle according to the preamble of claim 1.

[0002] Such an electric machine for a motor vehicle is, for example, already known from DE 10 2016 224 645 A1. The electric machine has a housing and a sound-insulating jacket surrounding the housing. Furthermore, the electric machine has at least one cooling channel arranged radially, i.e., in the radial direction of the electric machine, between the sound-insulating jacket and the housing, and through which a coolant flows for cooling the electric machine. This cooling channel is partially bounded by the housing and partially by the sound-insulating jacket.

[0003] The object of the present invention is to further develop an electric machine of the type mentioned above in such a way that a particularly advantageous cooling and a particularly advantageous noise behavior of the electric machine can be realized in a particularly space-saving manner.

[0004] This problem is solved by an electric machine with the features of claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the dependent claim.

[0005] To further develop an electric machine of the type specified in the preamble of claim 1 in such a way as to achieve particularly advantageous cooling and noise characteristics of the electric machine in a particularly space-saving manner, the invention provides that the cooling channel has recesses and raised areas formed in an outer surface of the housing. Furthermore, the noise-dampening jacket comprises a heavy foil.

[0006] The invention is based in particular on the following insights and considerations: The available installation space for an electric drive in a motor vehicle is inherently limited, which restricts the dimensions of the electric drive that can comprise at least one, or exactly one, electric machine, also known as an electric motor. The diameter of the electric machine, in particular, can be significantly restricted by the available installation space, since a cooling channel, a main housing, and a noise-dampening casing are typically added to the diameter of the stator of the electric machine, which is typically defined as its outer diameter. The resulting limitations on the maximum outer diameter of the electric machine can now be mitigated by the invention, as the cooling channel is integrated into the noise-dampening casing.The noise-dampening jacket is also referred to as a noise cover or NVH cover (NVH - Noise, Vibration, Harshness), as it prevents excessive noise emissions from the electric motor. The use of the heavy foil is particularly effective in preventing excessive noise emissions, resulting in a particularly favorable noise profile, also known as NVH behavior. Furthermore, the cooling channel's recesses and ridges create a large surface area for heat transfer from the housing to the coolant flowing through it, which is preferably liquid. This allows for particularly effective and efficient cooling of the electric motor.

[0007] Furthermore, it is conceivable that the noise-insulating casing incorporates a foam, thereby achieving particularly good noise performance. The invention makes it possible to realize both particularly advantageous cooling and particularly advantageous noise performance of the electric machine in a cost-effective, space-saving, robust, and functionally integrated manner.

[0008] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the single figure alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0009] The drawing shows in the only Fig. 1 A schematic and partially cutaway side view of an electric machine for a motor vehicle.

[0010] The only Fig. Figure 1 shows a schematic and partially cut-away side view of an electric machine 10 of a motor vehicle, also referred to simply as a vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car and can be driven electrically by means of the electric machine 10, in particular purely.

[0011] The electric machine 10 has a housing 12, also referred to as the main housing. Furthermore, the electric machine 10 has a [missing information - likely a specific feature or component]. Fig. 1. The stator is not readily apparent and is at least partially located within the housing 12. In particular, the stator is designed separately from the housing 12 and is rotationally fixed to the housing 12. The electric machine 10 also features a [missing information - likely a component or component]. Fig. 1. An unseen rotor is mounted on the housing 12, which can be driven by means of the stator and is thus rotatable about a machine axis of rotation, also simply referred to as the axis of rotation. The electric machine 10, whose axial direction coincides with the machine axis of rotation, can provide a drive torque for propelling the motor vehicle via the rotor. When the axial direction is mentioned before and below, this refers, unless otherwise specified, to the axial direction of the electric machine 10, whose radial direction is perpendicular to the axial direction and thus perpendicular to the machine axis of rotation. When the radial direction is mentioned before and below, this refers, unless otherwise specified, to the radial direction of the electric machine 10.The axial direction of the electric machine 10 is illustrated by a double arrow 14, and the radial direction of the electric machine 10 is illustrated by a double arrow 16. "Radial" refers to the radial direction, and "axial" refers to the axial direction. For example, the stator is rotationally fixed to the housing 12 by means of an interference fit.

[0012] The electric machine 10 also has a noise-dampening jacket 18 surrounding the housing 12, which is formed separately from the housing 12 and is at least indirectly connected to the housing 12. The electric machine 10 also has a cooling channel 20 arranged radially between the noise-dampening jacket 18 and the housing 12, which, for example, at least partially surrounds the housing 12 on its outer circumference. A coolant can flow through the cooling channel 10, by means of which the electric machine 10 is to be cooled. Preferably, the coolant is a liquid. Preferably, the coolant is a component of the electric machine 10. This is evident from Fig. 1. The cooling channel 20 is partially bounded by the housing 12 and partially by the noise-dampening jacket 18, in this case such that the cooling channel 20 is bounded radially outwards, in particular directly, by the noise-dampening jacket 18 and radially inwards, in particular directly, by the housing 12, in particular by an outer surface 22 of the housing 12. The outer surface 22 is an outer circumferential surface of the housing 12, the outer surface 22 of which faces radially outwards.

[0013] The noise-dampening jacket 18 serves two purposes: firstly, it acts as a cooling jacket, as it defines the cooling channel 20; and secondly, it acts as a noise barrier, also known as an NVH cover, because it prevents excessive noise emissions from the electric machine 10, particularly into the surrounding environment 24. For example, the noise-dampening jacket 18 is made of a plastic material. It can be seen that the noise-dampening jacket 18 forms a gap around the housing 12, which serves as the cooling channel 20.

[0014] In order to achieve both particularly advantageous noise characteristics and particularly advantageous cooling of the electric machine 10 in a space-saving manner, the cooling channel 20 has recesses 26 and raised areas 28 formed in its surface 22. In this design, the recesses 26 and the raised areas 28 alternate along the axial axis. The recesses 26 and the raised areas 28 create a particularly large surface area through which heat can be transferred from the housing 12 to the coolant flowing through the cooling channel 20. This allows for particularly effective cooling of the electric machine 10.Furthermore, the installation space requirement of the electric machine 10 can be kept particularly low, since the cooling channel 20 is arranged radially between the noise insulation jacket 18 and the housing 12 and is partially limited by the housing 12 and partially by the noise insulation jacket 18.

[0015] Furthermore, the noise-insulating jacket 18 has at least one noise-insulating element, in this case designed as a heavy foil 30.

[0016] Numerous configurations of the cooling channel 20, also simply referred to as a channel, are conceivable. For example, the depressions 26 and the raised areas 28 can form a meandering, helical, or double-helix shape for the cooling channel 20. Furthermore, it is conceivable that the channel could be configured as, in particular, a wide channel. It is evident that the raised areas 28 and the depressions 26 are formed, for example, by a structure incorporated into the surface 22 to create a particularly large area over which heat can be transferred from the housing 12 to the coolant.

[0017] At the in Fig. In the embodiment shown in Figure 1, the noise-insulating jacket 18 is sealed against the housing 12 by means of seals 32. Each seal 32 is, for example, designed as an O-ring.

[0018] Alternatively or in addition to the heavy foil 30, the noise-dampening element can be or comprise at least one foam. This foam is, for example, made of a plastic and / or designed as a foam. Furthermore, it is conceivable that the coolant, also referred to as the cooling medium, has a noise-dampening effect. Reference symbol list 10 electric machine 12 cases 14 Double file 16 Double file 18 soundproofing jacket 20 Cooling channel 22 outer surface 24 surroundings 26 In-depth study 28 increase 30 Heavy foil 32 Seal QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 224 645 A1

[0002]

Claims

[1] Electric machine (10) for a motor vehicle, comprising a housing (12), a sound-insulating jacket (18) surrounding the housing (12), and at least one cooling channel (20) arranged radially between the sound-insulating jacket (18) and the housing (12) and through which a coolant can flow for cooling the electric machine (10), which is partially bounded by the housing (12) and partially by the sound-insulating jacket (18), characterized by , that the cooling channel (20) has recesses (26) formed in an outer surface (22) of the housing (12) and elevations (28) formed in the outer surface (22) of the housing (12), wherein the noise insulation jacket (18) has a heavy foil (30). [2] Electric machine (10) according to claim 1, characterized by , that the depressions (26) and the elevations (28) form a meandering or helical or double-helix course of the cooling channel (20).

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