BACKGROUND OF THE INVENTION

The present invention relates to an electrical machine having a brush holder component and a plug module, and also to a corresponding modular system.

DE 42 25 496 A1 has disclosed an electrical drive unit in which an intermediate frame, into which a brush holder is integrated, is arranged between a pole pot and a gear mechanism housing. In this case, the drive unit is of modular construction, wherein a separate plug is arranged at different positions on the drive unit. As a result, for example, different variants with or without an electronics housing can be realized and, depending on the installation position of the drive unit, the plug connection can be adjusted in accordance with space conditions and the customer-specific mating plug. One disadvantage of a design of this kind is that the intermediate frame comprising the brush holder has to be equipped with different electronics components depending on the application and a total of three separate components, specifically the intermediate frame, the plug and the electronics housing, are varied. In this case, modifying the design of the intermediate frame comprising the brush holder in particular is very complicated since the adjustment of the carbon brushes has a great influence on undesired development of noise during operation of the drive unit.

SUMMARY OF THE INVENTION

In contrast, the electrical machine according to the invention has the advantage that the brush carrier component can always be designed with the same construction for different machine variants, and as a result the brushes can always be positioned in the same way in relation to the commutator in the pole housing. The total variance for different applications of the electrical machine is found in the plug module which is designed firstly with different plug outputs and secondly with different electronics components in accordance with the desired customer requirement. Since the brush holder component is always centered radially in the pole housing independently of the plug module, an action of force on the connection plug does not have a direct influence on the positioning of the brushes, and therefore no undesired noises are produced in the process. In order that the plug module can likewise be centered directly on the pole housing, axial projections of the plug module extend into corresponding recesses in the brush holder component. As a result, the axial projections can be radially supported directly against the pole housing, without making contact with the brush holder component in the process.

Advantageous developments of and improvements, to the embodiments specified in the independent claim are possible owing to the measures cited in the dependent claims. For example, the plug module advantageously has a base plate which axially closes off the pole housing, wherein only the rotor shaft protrudes out of the pole housing through a corresponding cutout in the base plate. As a result, the electronics components can be protected against swarf and carbon dust of the motor region. The connection plug is joined, for example, radially to the base plate, so that the mating plug can also be inserted into the connection plug radially entirely outside the pole housing.

The plug module can be produced in a particularly cost-effective manner from plastic, wherein the electrically conductive connection pins are designed as insert parts which establish an electrical connection to the brushes and possibly to other electronic components. In this case, the connection plug can be easily matched to the corresponding customer-specific mating plug, wherein the base plate can remain the same in respect of its basic structure. As a result, a plug module of this kind can be varied substantially more easily in terms of injection-molding than a brush holder component of relatively complex design.

In order to reduce the tolerance chain during assembly of the electrical machine, the plug module, by means of its axial projections which are integrally formed on the base plate, is centered directly on the inner side of the pole housing. Therefore, both the plug module and also the brush holder component have centering or positioning surfaces, which are in each case radially supported directly on the pole housing independently of one another, formed on their respective circumference.

In order that the electrical machines can be installed in relatively narrow spaces, such as a vehicle side door for example, the cross section of the pole housing can differ from a circle and have two flattened sides which, for example, are formed approximately parallel in relation to one another. Therefore, it is particularly expedient when both the plug module and also the brush holder component each have at least two centering surfaces which are supported against the opposite planar inner walls of the pole housing. In addition, two further axial projections are preferably formed on the plug module and are situated radially opposite one another and are radially supported against the inner walls of the pole housing which are in the form of a segment of a circle. Similarly, the brush holder component advantageously also has corresponding centering surfaces in the region of the circular inner walls of the pole housing.

For the purpose of mechanical end coupling of the plug module from the brush holder component, the cutouts in the brush holder component are larger than the corresponding axial projections of the plug module. In this way, it is possible to prevent the plug module from being radially supported directly against the brush holder component, as a result of which the positioning of the brushes in relation to the commutator is not adversely affected by undesired tilting or movement of the plug module.

An encircling edge is formed on the base plate of the plug module and axially bears firstly against the flange of the pole housing and, axially opposite, against a further housing, in particular a gear mechanism or electronics housing. For achieving a standardized interface between the pole housing and the respective gear mechanism housing, the encircling edge of the plug module can always be of standardized design for different variations of the plug module, so that identical connecting elements, for example screws, can also be used in each case.

A seal is particularly preferably formed on the encircling edge of the plug module, which seal seals off the entire housing of the electrical machine in a water-tight manner. In this case, the encircling edge is particularly expediently designed as a radial circumferential wall which at the same time is also part of the outer wall of the overall housing of the electrical machine.

Contact plugs can particularly advantageously be arranged radially inside the circumferential wall, which contact plugs extend axially away from the base plate toward the gear mechanism housing in order to make contact with corresponding mating contacts of an electronics system within the gear mechanism housing. As a result, the connection plug of an insert electronics system can also be electrically connected to the brush holder by means of the plug module.

An EMC shield which covers substantially the entire surface area of the plug module transversely in relation to the rotor shaft can optionally be arranged over the plug module. In this case, selectively only the region of the base plate and/or the region of the connection plug which is arranged radially outside the pole housing can be shielded. The entire motor—and in particular the region of the brushes—is surrounded by a Faraday cage owing to the contact-connection of the EMC shield to the pole housing.

In a further variant of the plug module, a centering dome which ensures a defined interface to the gear mechanism housing is formed around the central cutout of said plug module. Together with further adjusting surfaces on the outer edge of the plug module, both the radial and the tangential positioning of the gear mechanism housing in relation to the pole housing can be optimized.

For assembly of the electrical machine, the brush carrier component is axially inserted into the pole housing, before the plug module is then axially mounted onto the flange of the pole housing by means of the rotor shaft. In this case, the brush carrier component is axially pushed into the pole housing, wherein said brush carrier component is axially supported against correspondingly formed axial stops on the pole housing.

In this case, the brush carrier component is particularly advantageously axially arranged largely within the pole housing, so that the brush carrier component can be radially supported against the inner wall of the pole housing approximately over the entire axial extent of said brush carrier component. Tilting or tipping of the brush carrier component within the pole housing is prevented in this way. The brushes, which are arranged in a particularly space-saving manner here as hammer-type brushes radially inside the brush carrier component, are then optimally shielded by the circumferential wall of the pole housing in order to prevent emission of interference radiation from the electric motor.

After the plug module is mounted onto the pole housing, electrical conductor elements are electrically contact-connected to the plug module by the brush carrier component, and as a result electrically contact-connected to the connection pins of the connection plug. Here, for example, a connection wire of the brushes is particularly simply soldered or welded to corresponding contact elements of the plug module.

Owing to the arrangement of the connection plug radially outside the pole housing, the insertion direction and position of the corresponding customer-specific mating plug can be matched to the space conditions of the installation area in a particularly simple manner, without changing the basic design of the base plate or of the circumferential wall of the plug module. If the connection plug is angled in relation to the radial connecting web, the customer-specific mating plug can also be inserted in the axial direction, so that said mating plug extends axially along the pole housing. Owing to the design of a modular motor system with a brush carrier component which always remains the same, varying the electronic functions, such as rotor position detection or electronic interference suppression for example, can be shifted exclusively to the plug module which is easier to change. Owing to the pole housing interface which remains the same, good positioning of the brushes in a consistent and reliable manner in relation to the commutator can thereby be ensured and the electric motor can nevertheless be matched to a wide variety of customer requirements. In this case, the plug module can be fitted, for example, with different interference-suppression elements and can be designed with different rotary position sensors. Therefore, even in the case of different variants of the plug module, the pole housing/base plate of the plug module/gear mechanism housing interface can always remain the same, so that the flanges of the pole housing and of the gear mechanism housing are always reliably sealed off.

A particular advantage of the electrical machine is that the brush carrier component is electrically connected to the plug module, wherein electrical conductors are routed from the brushes to contact elements of the plug module - and are preferably soldered or welded to said contact elements after the plug module is axially mounted on that side which is situated axially opposite the brush holder component.

The base plate of the plug module runs approximately perpendicular in relation to the rotor shaft and bears in particular directly axially against the flange of the pole housing. The brush carrier component is, preferably by way of its circumferential wall which runs in the tangential direction, axially arranged completely within the pole housing.

The connection plug of the plug module can be formed with a plug collar, plug pins for a corresponding mating plug being arranged within said plug collar. In another module, the plug can be designed as contact lugs in the interior of the plug module, which contact lugs are contact-connected by means of corresponding clamping contacts—for example fork-type contacts or an insulation-displacement connection. In particular, the plug module always has a connection plug which is electrically contact-connected directly by a mating plug element being directly pushed on or inserted.

A step-down gear mechanism is advantageously mounted in the gear mechanism housing, which step-down gear mechanism passes on the drive torque from the electric motor to an output element which is designed, in particular, as an output pinion which protrudes out of the gear mechanism housing.

The gear mechanism is preferably designed as a worm gear mechanism in which a worm is arranged on the rotor shaft, which worm meshes with a worm gear in the gear mechanism housing. In this case, the rotor shaft with the worm protrudes axially through the base plate of the plug module into the gear mechanism housing.

