DE202012000841U1 - Electric machine and motor vehicle with an electric machine - Google Patents

Abstract

Electrical machine, comprising: - a rotor (1) arranged in a motor interior (5) on a rotor shaft (2); - A number of slip rings (7) arranged outside the motor interior (5) on the rotor shaft (2); - At least one labyrinth seal (13) is provided between the motor interior (5) and the slip rings (7).

Description

The present invention relates to an electric machine, in particular an electric motor or a generator, for example a starter generator. It further relates to a motor vehicle with such an electric machine.

In modern motor vehicles electric motors are increasingly being installed as drive motors. In some cases, externally excited synchronous machines are used which have a rotor made of a laminated core provided with a field winding.

In externally excited synchronous machines, the ends of the exciter winding via two slip rings, which are arranged on the rotor shaft, led out. The excitation voltage is applied to the excitation winding via carbon brushes. The two slip rings together with the basic body carrying them are often simply called "slip rings".

In such electric machines, the problem arises that the abrasion of the brush penetrates into the engine interior. This dust of electrically conductive particles can settle, for example as a conductive layer on machine elements and lead to electrically conductive creepage distances.

The DE 100 14 310 A1 discloses a floating gap seal for sealing the rotor space against the slip ring. In such a seal springs are provided which compress the sealing elements, but at the same time allow axial play. This makes the construction relatively expensive and prone to high stress problems.

In addition, rotating components can not be sealed with such a seal.

The object of the invention is therefore to provide an electrical machine in which the penetration of brush dust into the engine compartment is prevented as much as possible in a technically simple and at the same time particularly effective manner.

• – einen in einem Motorinnenraum auf einer Rotorwelle angeordneten Rotor;
• – eine Anzahl von außerhalb des Motorinnenraums auf der Rotorwelle angeordneten Schleifringen;
• – zwischen dem Motorinnenraum und den Schleifringen ist zumindest eine Labyrinthdichtung vorgesehen.

According to one aspect of the invention, there is provided an electric machine comprising:

• - A arranged in an engine compartment on a rotor shaft rotor;
• A number of slip rings arranged on the rotor shaft outside the engine compartment;
• - At least one labyrinth seal is provided between the engine compartment and the slip rings.

Under a labyrinth seal is here and below understood a non-contact seal whose sealing effect is based on the significant extension of the path through the labyrinth. The path extension can be achieved by a meshing of form elements on the rotor shaft and a fixed housing part.

In such an electric machine, the penetration of accumulating brush dust in the engine interior can be prevented by the distance traveled by the dust path is significantly extended into the housing interior and provided with labyrinth windings, which prevents easy passage of the dust through the opening.

The labyrinth seal may in particular be designed as a multi-groove labyrinth seal and have a plurality of series-connected in series sealing elements of intermeshing mold elements.

In one embodiment, the labyrinth seal is formed from molded elements on the rotor shaft and with these combing mold elements on a housing part, wherein the mold elements have a surface made of an electrically insulating material, for example plastic. The mold elements may also be formed entirely from plastic.

The housing part typically has an opening for the passage of the rotor shaft. In this opening, the labyrinth seal can be arranged concentrically around the rotor shaft.

If the slip rings are designed as dry-running slip rings, the use of the labyrinth seal is particularly advantageous because in this case occurs at the opening brush dust.

In one embodiment, the rotating electric machine is designed as an electric motor. It can also be designed as a generator or be operable both as a motor and as a generator.

Such electrical machines are suitable for use in a motor vehicle. They can be used both as drive motors fully integrated in the drive train and, for example, as starter generators or axle motors. According to one aspect of the invention, therefore, a motor vehicle is specified with a drive having the described electric machine. The motor vehicle can be designed as an electric or hybrid vehicle.

Embodiments of the invention will now be described with reference to the accompanying figure.

The single figure shows schematically a section through a rotor for an electric machine according to an embodiment of the invention.

The figure shows a rotor 1 for an electrical machine, in particular for a separately excited synchronous motor. The stator of the electric machine is not shown. The rotor 1 includes one on a rotor shaft 2 arranged rotor laminated core 3 , The rotor core 3 is in an engine room 5 arranged. The rotor shaft 2 is in the engine compartment 5 rotatable by means of a bearing 4 stored. The rotor shaft 2 is through an opening 9 in a housing part 6 , For example, a bearing plate, from the engine compartment 5 led out.

Outside the engine compartment 5 are on the rotor shaft 2 two slip rings 7 arranged over the means of carbon brushes 8th the excitation voltage to not shown excitation windings of the rotor 1 is created.

A slip ring, not shown, the slip rings 7 and the carbon brushes 8th surround.

During operation of the rotor falls on the slip rings 7 that act as dry (not in oil) running slip rings 7 are formed, electrically conductive coal dust from the carbon brushes 8th at. Through the opening 9 For example, the coal dust in the engine compartment 5 penetrate, settle there as an electrically conductive layer and lead to leakage currents.

To prevent this, the rotor points 1 in the area of the opening 9 on the rotor shaft 2 a labyrinth seal 13 on.

The labyrinth seal 13 is by a first form element 14 formed, with the housing part 6 connected and in the opening 9 is arranged, as well as by a second mold element 15 , the rotation with the rotor shaft 2 connected is.

The form elements 14 . 15 have intermeshing and non-touching "sealing lips" 16 on and are made of a plastic. Between these sealing lips 16 Through a path is formed, however, which is significantly longer than the length of the opening 9 , The coal dust in the engine interior 5 The distance to be traveled is thus through the labyrinth seal 13 significantly extended, resulting in the sealing effect.

In one embodiment, not shown, the labyrinth seal has a larger number of successively arranged, mutually meshing sealing lips. As a result, the distance to be traveled by the coal dust is additionally lengthened and the sealing effect is increased.

Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The above embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing description provides those skilled in the art with a plan for practicing at least one example embodiment, and wherein numerous changes can be made in the operation and arrangement of elements described in an exemplary embodiment without departing from the scope of the appended claims and their legal equivalents ,

LIST OF REFERENCE NUMBERS

1

rotor

2

rotor shaft

3

Laminated core

4

camp

5

Engine compartment

6

housing part

7

slip ring

8th

carbon brush

9

opening

13

labyrinth seal

14

first form element

15

second form element

16

sealing lip

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10014310 A1 [0005]

Claims (8)

Electric machine comprising: - one in an engine compartment ( 5 ) on a rotor shaft ( 2 ) arranged rotor ( 1 ); - a number of outside the engine compartment ( 5 ) on the rotor shaft ( 2 ) arranged slip rings ( 7 ); Between the engine compartment ( 5 ) and the slip rings ( 7 ) is at least one labyrinth seal ( 13 ) intended. Electric machine according to claim 1, wherein the labyrinth seal ( 13 ) is designed as a multi-groove labyrinth seal. Electric machine according to claim 1 or 2, wherein the labyrinth seal ( 13 ) from form elements ( 15 ) on the rotor shaft ( 2 ) and with these combing form elements ( 14 ) on a housing part ( 6 ), wherein the shaped elements ( 14 . 15 ) have a surface of an electrically insulating material. Electric machine according to claim 3, wherein the mold elements are made of plastic. Electrical machine according to one of claims 3 or 4, wherein the housing part ( 6 ) an opening ( 9 ) for the passage of the rotor shaft ( 2 ) and the labyrinth seal ( 13 ) concentrically around the rotor shaft ( 2 ) around in the opening ( 9 ) is arranged. Electric machine according to one of claims 1 to 5, wherein the slip rings ( 7 ) are designed as dry-running slip rings. Electric machine according to one of claims 1 to 6, which is designed as a generator. Motor vehicle with an electric machine according to one of claims 1 to 6.

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