EP2064801A1

EP2064801A1 - Electric motor, in particular for the windscreen wiper drive of a motor vehicle, with improved seating for the armature shaft bearing

Info

Publication number: EP2064801A1
Application number: EP07787416A
Authority: EP
Inventors: Detlef Lauk; Mario Huesges
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-09-08
Filing date: 2007-07-12
Publication date: 2009-06-03
Also published as: JP2010503371A; CN101512875A; US20090273250A1; WO2008028711A1; BRPI0716244A2; KR20090048625A; DE102006042340A1

Abstract

The invention relates to an electric motor (1), in particular for the windscreen wiper drive of a motor vehicle, comprising an armature shaft (10), which is mounted by means of at least one anti-friction bearing (11). Said bearing has an inner bearing ring (12), joined to the armature shaft (10) and also an outer bearing ring (13), held in a bearing seat, the latter consisting of a first half-shell (14) and a second half-shell (15), which are fitted together with their interiors facing one another to form a closed radially symmetrical bearing seat. The invention thus provides an electric motor (1) for the windscreen wiper drive of a motor vehicle with a simple seating for the anti-friction bearing (11) of the armature shaft (10).

Description

ELECTRIC MOTOR, ESPECIALLY FOR MOTOR VEHICLE WIPER DRIVE, WITH IMPROVED ASSEMBLY OF ANCHOR WAVE BEARING

The present invention relates to an electric motor, in particular for a windshield wiper drive of a motor vehicle according to the preamble of claim 1.

Electric motors of the above type usually drive via a screw to a transmission device, which are used, for example, to operate a windshield wiper system, a power window system, a seat adjustment or the like.

Such electric motors have different bearing arrangements, which for

Storage of the armature shaft serve both in the radial direction and in the axial direction.

State of the art

From the published patent application DE 199 26 171 Al an electric motor for a windshield wiper drive of a motor vehicle is known. This includes a bearing, which is used in a hard to reach bearing seat. Here, the bearing is axially fixed by means of a locking element in the bearing seat. This makes it possible to use the patch on the armature shaft bearing with the anchor in the bearing seat. The design of the electric motor and the associated gear housing is designed in several parts, so that the electric motor comprises a pole housing, which is flanged to the gear housing. The bearing seat is formed from the gear housing, wherein the heavy accessibility of the bearing seat is caused by the cup-shaped shape within the closed gear housing. The armature and the motor housing formed by the pole housing must be introduced by means of a complex joining process in the gear housing, wherein in addition to the connection of the motor housing with the gear housing by means of screws or the like initially only the locking element for a positive connection. The assembly is therefore difficult, disassembly is hardly possible and only with increased effort.

The published patent application 197 27 120 A1 discloses an electric motor for a windshield wiper drive of a motor vehicle with an electric motor, which has an in Has substantially cup-shaped pole housing in which an anchor is arranged. At the pole housing, a transmission housing is attached, which serves to receive transmission elements. An armature shaft extends from the pole housing to the transmission housing and is mounted on the one hand in the pole housing and on the other hand in the transmission housing. An assembly of the individual components is also extremely expensive, since first the armature must be inserted into the pole housing, to then introduce the storage side of the gear housing. For this purpose, a headband is provided, which axially fixes the rolling bearing in the transmission housing. The rolling bearing is pressed into the bearing seat within the gear housing and enclosed by the gear housing on the full circumference. Disassembly of the bearing requires the release of the interference fit, which is often accompanied by a considerable disassembly effort.

It is therefore the object of the present invention to provide an electric motor for a windshield wiper drive of a motor vehicle, which is a simple

Recording the rolling bearing of the armature shaft allows.

The object is achieved on the basis of an electric motor according to the preamble of claim 1 in conjunction with its characterizing features. Advantageous developments of the invention are specified in the dependent claims.

The invention includes the technical teaching that the bearing seat is formed of a first half-shell and a second half-shell, which are arranged opposite one another with their shell inner sides to form a closed radially symmetrical bearing seat.

The invention is based on the idea to use two shells to form a bearing seat, which form a radially symmetrical bearing seat in an opposing arrangement. During assembly, the armature can be used in a simple manner with the mounted on the bearing shaft bearings in the first half-shell, with a simple insertion of the second half-shell to form the radially symmetrical bearing seat is possible. The half shells form in the assembled arrangement a passage for the armature shaft which is larger than the armature shaft itself. Depending on requirements, a sealing element such as a felt ring or a lip seal for sealing against contamination and the like may be previously attached to the armature shaft to be held and received by the half-shells during operation. The half-shells each have a circular portion of the bearing seat of 180 °, so that an insertion of the rolling bearing in the first and second

Half shell can be done without a Krafterfordernis.

Advantageously, the electric motor is arranged on a transmission housing, wherein the first half-shell is formed from a body portion of the transmission housing. The gear housing is thus integrally formed and the same material with the first half-shell, so that it only passes from the transmission housing and is arranged in the form of a body portion of this. The gear housing can be manufactured by means of an injection molding process, so that the geometric configuration of the first half-shell can be easily made possible as a one-piece molding on the transmission housing. Thus, the transition of the transmission housing into the first forms

Half shell a mechanical connection of the electric motor to the transmission housing.

In the transmission housing, a corresponding transmission means may be arranged, which drives a worm wheel, for example, via a worm arranged on the armature shaft of the electric motor. Thus, the inclusion of the bearing can be a mechanical

Form interface between the electric motor and the transmission housing.

According to a further embodiment of the invention it is provided that the half-shells comprise a front and a rear shoulder in order to support the armature shaft axially via the roller bearing in the bearing seat. The rolling bearing offers the possibility of absorbing axial forces in addition to the radial guidance, so that possible starting mushrooms, starting springs or other arrangements for absorbing axial forces within the armature shaft bearing can be dispensed with.

The shoulders of the half-shells can thereby encompass at least the bearing outer ring, whereby the bearing inner ring can at least adjacent to the shoulders of the half-shells perform a rotation. It should be noted that the bearing inner ring rotates only within the shoulders, without touching them or entering into a non-positive connection with the shoulders. The shoulders form a passage of the armature shaft, which is for example slightly larger than the armature shaft itself. - A -

Thus, it is possible to provide a grease lubrication of the rolling bearing. The rolling bearing may, for example, be designed as an open rolling bearing in order to obtain possible grease reserves in or in the vicinity of the bearing.

If an axial force is introduced into the armature shaft, this is transmitted via the

Bearing inner ring, the rolling elements and the bearing outer ring transferred to the half shells. Due to the division of the half-shells an axial securing of the bearing outer ring can be made possible without great technical effort and without the addition of retaining rings such as a snap ring.

According to a further embodiment of the invention, the electric motor comprises a pot-shaped or tubular pole housing which encloses the first and the second half-shell at least in sections over the outer circumference thereof. The pole housing forms the housing of the electric motor and conventionally consists of a soft iron shell. It may have a tubular portion into which the half shells brought together can be inserted. The covering of the half-shells by the pole housing can be done either in sections. Advantageously, the half shells are complete, i. used over its entire width in the pole housing.

On the outer circumference circumferentially circumferential grooves can erstrecxken, wherein the pole housing can be rolled in the grooves, to connect the half-shells form-fitting with the pole housing. The half-shells can be fixed by rolling in the pole housing, wherein the material of the pole housing at least partially presses into the grooves of the half-shells. This creates a positive fit

Connection between the pole housing and the half shells.

Furthermore, it is possible, alternatively to the Anrollierung of the pole housing to caulk the half-shells with the pole housing by distributed on the circumference plastic deformations of the pole housing are made such that also a positive connection can be made with the half shells.

The Anrollierung can take place either over the outer circumference of the pole housing, wherein a bending or crimping of the pole tube in the end region is possible, so that the formed flanged edge enclosing the half-shells and thus within the pole housing guaranteed. The attachment of a stop within the pole housing may limit an insertion of the half-shells in the pole housing, so that the crimping edge clamps the half-shells against the stop. In the case of a screwing of the half shells in the pole housing, for example, by at least one radially supplied screw securing the half shells within the pole housing is also possible, with the use of such connecting means disassembly is simplified.

According to a further advantageous embodiment of the invention, the first half-shell or the gear housing and / or the second half-shell of a

Plastic material produced. By means of such a selection of materials, a simple injection molding production of the components is possible. It is also possible to use the flexibility or the elastic behavior of a plastic material to the effect that the rolling bearing within the half shells by a simple way to install without play. But the one attached to each other by the opposite one another

Half shell formed bearing seat has a diameter which is chosen slightly smaller than the bearing outer ring of the rolling bearing, so that a press-fitting fit can be created. The half-shells can thus be clamped to the rolling bearing and connected in the pole housing.

The overall arrangement of bearings, the first and second half-shell and the pole housing can be formed without play, the resilience of the plastic material of the half-shells allows the application of a defined bearing preload. The plastic material may, for example, from the group of polycarbonates, polystyrenes, acrylonitrile-butadiene styrenes, the

Polymethylmethacrylates or be carried out from a similar group.

A further advantageous embodiment of the invention provides that the rolling bearing is designed in the manner of a ball bearing, by means of which in addition to radial forces and axial forces are aufhehmbar. In this case, ordinary deep groove ball bearings are applicable, with other types of bearings, such as a shoulder ball bearing, represents a possible embodiment. The inclusion of axial forces should advantageously allow the bearing to transfer the axial force introduced by the worm gear in the armature shaft into the arrangement of the half shells and the pole housing. Advantageously, the armature shaft is mounted on at least one further side facing away from the transmission housing by means of a sliding bearing. The plain bearing is accommodated in a circular disc-shaped bearing plate, which is at least partially enclosed by the outer circumference of the pole housing and is positively connected by means of a groove with the pole housing. The bearing plate can be at the same

Way be secured inside the pole housing, as the first and second half-shell. This takes up the plain bearing within a bore, wherein the plain bearing can be pressed for example in the bearing plate.

The end shield can be closed advantageously to prevent ingress of contaminants. Furthermore, a space for filling with bearing grease can be provided. Due to the simple arrangement of the bearing plate this can be made in one piece, wherein the positive attachment of the bearing plate can be carried out within the hollow tube in the same way as the arrangement of the first and second half-shell. The plain bearing is used only for

Recording of radial forces, and can be considered as a floating bearing with respect to the entire bearing assembly.

It is also possible to store the armature shaft on the part of the worm, wherein the bearing is introduced within the gear housing. Thus, there is the

Possibility to store the shaft with three bearings, of which only a bearing must be designed as a fixed bearing, which is formed by the rolling bearing.

Further, measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the single figure.

embodiment

It shows:

The figure is a schematic cross-sectional view of an electric motor for a windshield wiper drive with a bearing assembly according to the present invention. The electric motor 1 shown in the figure consists of an armature shaft 10, which is rotatably supported by a roller bearing 11 and a sliding bearing 21 within a pole housing 19. The rolling bearing 11 is in addition to the rolling elements of a bearing inner ring 12 and a bearing outer ring 13. The bearing inner ring 12 is pressed onto the armature shaft 10 or secured axially by means of securing elements. Of the

Bearing outer ring 13 is located in a bearing seat, wherein the bearing seat itself is formed by a first half-shell 14 and a second half-shell 15.

The half shells 14 and 15 extend at an angle of 180 ° around the bearing outer ring 13 around. By the first half-shell 14 and the second half-shell 15, a radially symmetrical bearing seat is formed, wherein the half-shells 14 and 15 enclose the rolling bearing 11 on the full circumference. The first half shell 14 is formed from a body portion of a gear housing 16, the gear housing 16 is thus made of the same material, i. in one piece in the first half-shell 14 via. Thus, the first half-shell 14 forms a mechanical coupling of the electric motor 1 to the

Transmission housing 16 of the windshield wiper drive.

The rolling bearing 11 is designed as a ball bearing, which can accommodate both radial forces and axial forces. Via a screw 23, an axial force is introduced into the armature shaft 10, so that it is transferred via the bearing inner ring 12, the rolling elements and the bearing outer ring 13 in the first and second half-shell 14 and 15. The bearing shells 14 and 15 are inserted in a pole housing 19, and caulked axially by means of a Anrollierung in this.

The Anrollierung via grooves 20, wherein the first half-shell 14 and the second

Half shell 15 each have a closed circumferential groove on the respective outer side. The rolling takes place in each case via the groove 20, so that the material of the pole housing 19 is at least partially pressed into the grooves 20. Furthermore, the pole housing 19 is provided with a flanged edge 24, which also form an axial securing of the first and second half-shell 14 and 15 within the pole housing 19.

For the transfer of the axial forces from the bearing outer ring 13 in the first and second half-shell 14 and 15, these have a front shoulder 17 and a rear shoulder 18, which extend in the radial direction at least over the bearing outer ring 13. The bearing outer ring 13 is thus between the front shoulder 17 and the rear shoulder 18 axially held, so that it is axially fixed in both directions.

As shown in the figure, the front shoulder 17 and rear shoulder 18 are made in diameter such that they extend radially to just before the armature shaft 10 to einhausen the rolling bearing 11. The gear side remote from the armature shaft is rotatably supported via a sliding bearing 21 which is disposed within a bearing plate 22. The bearing plate 22 also has on its outer side a groove 20 into which the material of the pole housing 19 is at least partially pressed by a Anrollierung. Thus, the end plate 22 is fixed within the pole housing 19. The bearing plate 22 is formed as shown in the manner of a closed circular disc to close the sliding bearing 21 relative to the outside of the electric motor 1.

The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. For example, it is possible to provide on the first half-shell as well as the second half-shell a respective receptacle of the carbon brushes, which cooperate with the collector of the armature assembly of the electric motor. In this case, projections for receiving a device may be provided on the side of the rear shoulder, which include, for example, so-called coal shafts or other recordings of coal to the spring-loaded contact pressure to the collector of the anchor package. Further, not shown in the figure ring, lip or felt seals can be provided within the front and rear shoulder of the first and second bearing shell, which provide a simple seal of the interior of the electric motor 1 from the environment.

Claims

claims

1. electric motor (1), in particular for a windshield wiper drive a

Motor vehicle with an armature shaft (10) which is mounted by means of at least one rolling bearing (11) having a bearing inner ring (12) which is arranged on the armature shaft (10), and a bearing outer ring (13) which is accommodated in a bearing seat , characterized in that the bearing seat of a first half-shell (14) and a second half-shell (15) is formed, which are connected to form a closed radially symmetrical bearing seat with their shell inner sides opposite each other.

2. Electric motor (1) according to claim 1, characterized in that the electric motor (1) on a transmission housing (16) is arranged, and the first half-shell (14) of a body portion of the transmission housing (16) is formed.

3. Electric motor (1) according to claim 1 or 2, characterized in that the half-shells (14, 15) have a front and a rear

Shoulder (17, 18) to support the armature shaft (10) axially via the rolling bearing (11) in the bearing seat.

4. Electric motor (1) according to one of the preceding claims, characterized in that the electric motor (1) is a pot-shaped or tubular

Pol housing (19) which encloses the first and the second half-shell (14, 15) at least in sections over the outer circumference.

5. Electric motor (1) according to claim 4, characterized in that the half-shells (14, 15) in the outer circumference at least one circumferential groove (20), wherein the pole housing (19) in the region of the groove (20) is rolled to the Half shells (14, 15) form-fitting manner with the pole housing (19) to connect.

6. Electric motor (1) according to one of the preceding claims, characterized in that the gear housing (16) and thus the first half-shell (14) and / or the second half-shell (15) are made of a plastic material.

7. Electric motor (1) according to any one of the preceding claims, characterized in that by the successive half shells (14, 15) formed bearing seat has a diameter which is slightly smaller than the bearing outer ring (13) of the rolling bearing (11) to a Press fit is created.

8. Electric motor (1) according to one of the preceding claims, characterized in that the armature shaft (10) is mounted on at least one further the transmission housing (16) facing away by means of a sliding bearing (21).

9. Electric motor (1) according to claim 8, characterized in that the sliding bearing (21) in a circular disk-shaped

Bearing plate (22) is accommodated, which is at least partially enclosed by the outer circumference of the pole housing (19) and by means of a groove (20) positively connected to the pole housing (19).

10. rear window wiper system, in particular for a motor vehicle with a

Electric motor (1) according to one of the preceding claims.