Housing comprising at least one functional element of an electrical machine

Functional elements are difficult to mount on a housing based on known methods, on which at least one functional element for an electric motor is situated. A housing is configured such that functional elements to be mounted on the housing are mountable on the housing from the outside.

FIELD OF THE INVENTION

The present invention is directed to a housing.

BACKGROUND INFORMATION

From German Published Patent Application No. 198 33 802, an electric motor having a housing is known, the housing having elements of the electric motor, such as brushes, brush holders, bearings, bearing supports. Assembly of these elements is very complicated. For example, when installing an armature having a commutator in the housing, the brushes and their holder must be pushed back. It is not possible to install the brushes once the commutator is installed.

From German Published Patent Application No. 199 26 171, an electric drive having a gearbox including a bearing support and a brush holder for an electric motor is known. Assembly of these elements is also very complicated.

U.S. Pat. No. 5,661,357 describes a housing having a bearing support and holder for a bearing of an electric motor, the bearing forming one unit with the housing.

European Published Patent Application No. 911 949 discusses a plug-and-socket device having electrical power supply leads for an electric motor, the leads being mounted on a gearbox housing.

European Published Patent 739 077 No. describes a brush holder having brushes mounted in axial direction on an electric motor gearbox.

PCT Publication No. WO 97/43819 describes an electric drive where a plug having electric leads is mounted on a housing from the outside.

German Published Patent Application No. 43 37 390 describes an electric drive unit, where the brush holder along with the brushes is mounted on the housing from the outside.

SUMMARY OF THE INVENTION

The housing according to the present invention has the advantage that the mounting of the functional elements on the housing is simplified in a straightforward manner.

It is advantageous for the housing to have a bearing support, into which a bearing for a shaft of an armature of an electrical machine may be installed, preferably from the outside, because this simplifies assembly.

It is of further advantage, when the housing has at least one mount for supporting and/or holding the functional elements.

Advantageously, at least one rotational speed-sensing element of an electrical machine, electrical conductor tracks, or at least one electric interference suppression coil are mountable on the housing from the outside as functional elements.

It is advantageous if the bearing support and holder are designed as one piece with the housing, since this eliminates the need for additional fastening elements for attaching the bearing.

This configuration of the housing advantageously integrates a brush holder and/or end shield into the housing. This saves on the cost and time of mounting a brush holder or an end shield on the housing.

The housing may advantageously form a magnetic return path element for an electric motor.

If the housing is electrically or magnetically conductive, it is advantageous to electrically insulate the mount from the housing.

To electrically interconnect the functional elements, it is advantageous to inject electrical conductor tracks into the housing.

The housing may advantageously form part of an electric drive, such as being one unit with a gearbox, for example, reducing the number of parts to be installed.

The housing may advantageously have bushings for the brushes, eliminating the need for mounting additional brush boxes.

Together with the brush box, the mount for interference suppression coils, etc., the housing integrates and combines the functions of a brush holder in an advantageous manner.

The housing may be closed at one end and contain a bearing support, integrating and combining the functions of an end shield in an advantageous manner.

The housing offers advantages during assembly, because the brush and/or interference suppression coil, etc. do not have to be mounted until after the armature and its shaft are placed in the housing.

DETAILED DESCRIPTION

FIG. 1shows a housing1, embodied according to the present invention, in exploded view. Housing1may be a housing of an electrical machine such as an electric motor or an electric generator.

Housing1has a hollow cylindrical shape, for example, and converges at one axial end, for example, conically toward the inside in a radial direction31, for example. In addition, housing1has brackets40by which it is suspended in another housing.

At least one functional element3for an electric motor is attachable from the outside to housing1. From the outside means that functional elements3are mountable after housing1and an armature of the electrical machine inserted into housing1have already been assembled. In particular, functional elements3are mountable to an outer lateral surface38of housing1.

Housing1, for example, has at least one mount12, configured, for example, as a pocket, for a functional element3, in which mount the latter is supported and/or guided and/or fastened. At one axial end of housing1there is a bearing support6, into which a bearing9can be mounted from the outside, but also from the inside. Bearing9may be fastened to housing1using a bearing attachment10, in the form of a clamping ring, for example. Bearing support6and holder or attachment10may also form one piece with the housing as shown in European Published Patent Application No. 703 655.

An axial direction30, such as a rotational axis of an armature76(shown schematically inFIG. 2) of the electrical machine situated in housing1, forms a center axis for housing1. Perpendicular to the axial direction30, for example, housing1has, as a mount12, at least one brush box16, into which one brush15, as a functional element3, may be inserted from the outside in at least partially radial direction31, and is movable obliquely or perpendicularly to axial direction30. Brush15is passed through brush box16and rests on a commutator of an electrical machine, the commutator being situated inside of housing1.

Furthermore, at least one electric interference suppression coil18, for example, is present as functional element3. Coils18are also held in a mount12on the outside. Coil18is electrically connected to at least one brush15via electrical connections.

For support or electrical interconnection of functional elements3, a connection element21is used that may also be plugged into a mount12, configured as a clamp retainer, for example, of housing1. Connection element21has a terminal slot, into which an electrical connection of a coil18and of a brush lead may be jointly clamped and thus be electrically connected with one another.

A spring33, which presses brush15against commutator43(FIG. 3), is also installed on or in housing1.

A rotational speed measuring element72, shown schematically inFIG. 1, such as a Hall sensor may also be installed on housing1from the outside.

Housing1, therefore, is capable of integrating the function of an end shield24and/or a brush holder27. Housing1may be molded entirely of plastic.

Part of housing1may also form a magnetic return path element or a field frame for the electric motor. If housing1is made of an electrically conductive material such as a metal, mounts12are electrically insulated from housing1. This may be done, for example, by mounting mounts12made of plastic on housing1, or by molding mounts12made of plastic onto housing1. Housing1may also be molded of a mixture of plastic and a magnetically conductive material, so that it serves as a magnetic return path element. Electrically insulated mounts12may also be molded onto housing1in this case.

For electrical connection of functional elements3,15,18, electrical conductor tracks74may be injected into housing1.

FIG. 2shows a housing1according to the present invention with functional elements3installed. InFIG. 2, two outer electrical connections36are shown, through which an electric current may pass to an armature winding of the electrical machine via coils18, brushes15, and the commutator.

Coil spring33is rolled up in a circle when unstressed. At one end46, coil spring33has a V-shape49, for example.

Commutator43rotates in an internal opening52of housing1. Housing1has, near opening52, a projection55extending from opening52in a roughly radial direction70along brush box16. This projection55forms an undercut50with a facing wall61of brush box16, in which the V-shape of spring33is wedged. When spring33is fastened in this manner, it continues to be rolled up until brush15is capable of being pushed into brush box16. Brush15, at an end facing away from commutator43, has a bevel58, to which the circular part of the still-rolled-up loaded coil spring33is applied. Brush15is pressed against a second wall64of brush box16and against commutator43by spring33. Wall61of brush box16, situated opposite second wall64, has a curved shape that is, to some extent, adapted to the shape of spring33between V-shape49and the rolled-up part.

Brush15is guided by second wall64and a section67at projection55. Spring33, configured as a coil spring, is able to generate—in contrast to a helical spring—an almost constant force despite wear on the brush length. The length of brush box16in radial direction70is also better utilizable, since spring33, configured as a coil spring, uses less axial space in the housing than a helical spring.

The housing1may be part of an electrical drive unit78, which may include a gear unit80, both of which are shown schematically inFIG. 2.