WO2010043407A2

WO2010043407A2 - Electric motor

Info

Publication number: WO2010043407A2
Application number: PCT/EP2009/007439
Authority: WO
Inventors: Helmut Sesselmann; Holger Schrepel
Original assignee: Brose Fahrzeugteile Gmbh & Co.
Priority date: 2008-10-18
Filing date: 2009-10-16
Publication date: 2010-04-22
Also published as: DE202008013947U1; WO2010043407A3

Abstract

The invention relates to an electric motor (1) having an armature (13), comprising a brush commutator (18) having a number of brushes (22) and a number of brush disks (20) associated with the armature (13), a number of stator magnets (26) and a housing (2, 3), in which the armature (13) is rotatably mounted and in which the stator magnets (26) are accommodated. The brushes (22) are furthermore associated with the housing (2, 3) in a structurally fixed manner. A fixed housing section (7) and a movable housing section (23), which can be rotated about the rotation axis (31) of the armature (13) relative to the fixed housing section (7) are provided, wherein the stator magnets (26) are associated with the movable housing section (23). Said design enables simple adjustment of the position between the outer magnetic field and brushes (22). Commutation within the neutral zone is possible by simply rotating the movable housing section (23).

Description

Description electric motor

The invention relates to an electric motor with an armature, comprising a brush commutator having a number of brushes and a number of armature associated brush blades, with a number of stator magnets, and with a housing in which the armature is rotatably mounted and in which Stator magnets are added, the brushes are structurally associated with the housing.

An electric motor of the type mentioned is u.a. as an actuator in automotive technology, in particular for the motorized adjustment of an actuating element, such as a sunroof, a vehicle window, a vehicle door or vehicle door, and a seat or a seat part used.

In a brush-commutated electric motor, the armature, also called a rotor, is usually wound with a number of exciting coils, which are supplied with an exciting current via the commutator. For this purpose, the anchor usually comprises a stack of sheets with grooves and pole shoes, wherein the field windings are received in the grooves of the stack of sheets.

The commutator usually includes a lamellar ring rotatably coupled to the armature which carries a number of electrical contact pads called lamellae. The contact fields are distributed over the circumference of the disk ring and electrically connected to the field windings. The lamellae and thus the field windings are energized by brushes of conductive material, in particular of graphite, resting against the lamellar ring. The brushes (usually two) are structurally connected to the housing of the electric motor, so that the lamellae move with a rotation of the armature past the brushes and are alternately contacted. In other words, the excitation windings are switched successively or alternately via the associated slats between the brushes, to which in particular

BESTÄT1GUNGSKOPIE special DC voltage is applied as the supply voltage. About this commutation, ie the successive wiring of different excitation windings, an approximately constant torque is generated for the corresponding wound anchor in a constant external magnetic field. To construct the external magnetic field, the electric motor of the type described above has a number of stator magnets in whose magnetic field the armature rotates with its field windings. The stator magnets can be given either by permanent magnets or by separately energized electromagnets.

Upon rotation of the armature, it inevitably leads to a periodic bridging adjacent slats through the respective contacting brush. If the field line course of the external magnetic field is not aligned parallel to the bypass current or the brushes are not arranged in a field-free region, an induction voltage builds up, which is associated with the undesired consequences of a brush fire. The brushes are therefore usually arranged to the stator magnet so that the Bürstenort the desired field line or a field-free area is present. In this context, one also speaks of placing the brushes in the so-called neutral zone of the external magnetic field. Brush fire should be avoided, as this leads to increased corrosion of both the fins and the brushes and also causes radio interference. Also, an increasing brush fire is associated with a power dissipation of the electric motor.

As a result of the energization of the exciter windings, a further magnetic excitation field is built up in addition to the external magnetic field. The total magnetic field then results from a superposition of both magnetic fields. Upon rotation of the armature and thus of the energized exciter windings, superposition thus leads to a positional shift of the neutral zone that depends on the direction of rotation. However, the structurally arranged brushes thus reach outside the desired neutral zone, so that the undesired brush fire increases depending on the direction of rotation and the speed of rotation. In order to avoid the unwanted brush fire, so-called turning poles are used, which are energized via the excitation windings and arranged so that they compensate for the effects of the exciter field on the positional shift of the neutral zone. Also, according to a preferred direction of rotation of a brush-commutated electric motor, the brushes are arranged from the outset so that they are then placed within the neutral zone with the engine running.

Disadvantageously caused by the provision of Wendepolen unwanted additional costs. If the brush arrangement is structurally adjusted to a preferred direction of rotation of the electric motor, this results in two different installation variants of the electric motor, namely for a right and for a left-hand installation. The provision of two different installation variants in turn causes additional costs.

The object of the invention is to provide an electric motor of the type mentioned, in which with structurally simple means the brush fire is reduced.

The object is achieved for an electric motor of the type mentioned in the present invention, that a fixed housing portion and a relative to the fixed housing portion about the axis of rotation of the armature rotatable movable housing portion are provided, wherein the movable housing portion associated with the stator magnets.

The invention is based on the idea not to twist the brushes but the stator magnets with respect to the axis of rotation of the armature. The stator magnets are arranged to generate the static magnetic field around the armature with a certain rotational symmetry, so that with a rotatable around the axis of rotation of the armature movable housing portion, which are associated with the stator magnets, a structurally simple way to a relative positional adjustment between brushes and stator magnet results. With other Ren words are not the brush against the external magnetic field, but the external magnetic field with respect to the fixed brushes twisted. For a simple tracking or adaptation of the resulting during operation of the electric motor superpositioned magnetic field is possible. The operationally changing neutral zone of the superpositioned magnetic field is moved by changing the position of the static magnetic field to the location of the brushes.

For this purpose, a movable housing portion is provided, which are associated with the stator magnets. If the housing section with respect to the axis of rotation of the armature with a certain rotational symmetry or completely rotationally symmetric running, recordable in the form of a pole tube with a corresponding cross section, it can be adjusted with a single motor variant, an adjustment of the position between brushes and external magnetic field for a left and for clockwise be, to which the stator magnet bearing movable housing portion is adjusted in different directions of rotation. The provision of two engine variants for a left and for a right installation is therefore no longer necessary.

By structurally simple to be realized feature of a rotatable housing portion a simplified adjustment of the position between brushes and external magnetic field is dependent on a given direction of the electric motor possible, so that the brush fire can be avoided. This can be achieved in the preferred direction of rotation of the electric motor performance, with the brush fire is avoided. When using the electric motor for an actuator in which, for example, an actuating element is moved once against and once with gravity, it is recommended to provide the increase in performance for the direction against gravity. Thus, the power of the electric motor is increased as desired during a movement of the control element against gravity (ie when lifting). When moving the actuator with gravity (ie, when lowering), the power of the electric motor is reduced, however, a high power in this direction of movement is not needed. By bridging adjacent lamellae described at the outset by the respectively contacting brush, the exciter current is impressed by a periodic corrugation, also called ripple, which is dependent on the rotational speed of the armature. This ripple of the exciting current can be used in particular to determine the rotational speed of the electric motor and thus ultimately the position of a driven actuating element. The invention offers the further advantage that the ripple signal can be amplified or attenuated by a corresponding rotation of the movable housing section. Although a strong Ripplesignal indicates too high armature reaction, which suggests a non-optimal commutation. However, this measure can be justified in order to obtain an evaluable ripple signal.

In a preferred embodiment, as already mentioned, the movable housing section is designed in the form of a separate pole tube carrying the stator magnet. The pole tube extends with constant cross-section along the axis of rotation of the armature. In the case of a circular cross section of the pole tube, the electric motor always has the same external shape regardless of the selected angle of rotation of the pole tube. Likewise, it is also possible, the pole tube with a certain rotational symmetry, for example, 3-, 4-, or n-count, to design and provide a desired stage setting. The pole tube in this case, for example, a three-, four-, or n-square pipe cross-section.

In a preferred embodiment, the fixed housing comprises a gear portion and a contacting portion, wherein the movable housing portion is rotatably supported between the gear and the contacting portion. In such a compact motor, the armature guided through the movable housing section drives the transmission situated in the transmission section via a corresponding shaft, wherein the commutator side of the armature is mounted in the contacting section and electrically contacted there. In this construction variant results in a simple way to support the movable housing section and in particular a separate pole tube. For example, the housing section can be rotated between see the two housing sections clamped or mechanically connected via appropriate rotary joints.

According to a first advantageous variant, the movable housing section is rotatably mounted on the fixed housing section by means of a step-adjustable latching connection, wherein the latching connection comprises a first latching connection part, which is assigned to the movable housing section, and a second latching connection part, which is assigned to the fixed housing section. A locking connection offers the possibility of a relatively wide adjustment while simultaneously determining the location. The step width of the latching connection or the rotation angle predetermined per latching can be set within wide ranges by constructive design according to the desired specifications.

Conveniently, the first detent connection part is arranged along the circumference of the movable housing section. In this case, the movable housing section connected to the fixed housing then engages over its circumference in the correspondingly complementary second latching connection part. The latching connection is thus achieved directly over the movable housing section.

In another advantageous embodiment variant, the first latching connection part is arranged on the stator magnet. This variant offers the possibility to move the locking connection into the interior of the movable housing section, so that such is no longer visible from the outside. The locking connection with the fixed housing is now realized directly on the stator magnet.

As a rule, a complete rotation of the stator magnet to adapt the magnetic field position is not required, it is sufficient to form the locking connection parts or at least one of the locking connection parts only partially in the circumferential direction. The length of the peripheral portion is to be chosen so that, depending on the engine type still sufficient adjustment of the position between the magnetic field and brushes to reduce the brush fire is possible. If a locking connection is selected to a stepped setting, it can be provided on both sides of the movable housing section or only on one side. The not configured with a latching connection side of the movable housing portion may in this case be, for example, a rotary joint of any design. If a two-sided latching connection is selected, this results in a stable positional fixation of the movable housing section between two fixed housing sections, for example between the contacting section and the gearbox section.

For a stable position fixation of the transmission section, via which the adjusting element is driven, it is recommended to provide the latching connection between the movable housing section and the transmission section.

The latching connection can in principle be formed in a known manner. In particular, circumferentially extending complementary gears offer. About the tooth spacing in this case the adjustable per locking rotation angle is specified.

In another, likewise advantageous embodiment variant, the latching connection is formed by means of interengaging circumferential sections of the fixed and the movable housing section. In particular, it may be provided in this case to predetermine the peripheral sections to achieve a specific rotational position of the movable housing section type-specific. For example, the gear section can be integrally formed with an axially projecting housing section with which a desired angle of rotation of the movable housing section can be predetermined. In particular, the peripheral portion can also be cut type-specific in order to predetermine the angle of rotation of the movable housing portion, if necessary. It is also conceivable to form the cooperating circumferential sections in the manner of an insert, which can then be rotated in the corresponding housing section. Of course, the peripheral portion may also be specified in the production type-specific. Advantageously, engage the peripheral portions of the fixed housing portion for fixing the rotational angle between the stator magnets. In this embodiment variant of the movable housing portion does not have to be pre-configured accordingly structurally, as is usually given between the stator magnet used space for a corresponding positive connection with the peripheral portions of the fixed housing portion.

In a further preferred embodiment variant of the movable housing portion is connected via a rotary coupling with the fixed housing portion. The rotary coupling allows any rotation of the movable housing portion in both directions and optionally at any angle. To adjust the rotational position of the movable housing portion can be fixed to the desired rotation of the fixed housing section. For example, this is done by means of a bond, a weld or other connection techniques.

In the case of a Drehankopplung a controllable drive for actuating the rotary coupling is conveniently provided. By means of such a drive, the angle of rotation of the movable housing section during operation of the electric motor can be adapted to the changing superpositioned total magnetic field. In this way, a continuous positional adjustment between the external magnetic field and the brushes with respect to a small brush fire is made possible. By a small adjusting motor for driving the rotary coupling thus the stationary external magnetic field, if necessary, a changing load or a changing current consumption of the armature can be tracked, so that overall reduces the brush fire and the power of the electric motor is increased. Especially with large electric motors can thus be dispensed with Wendepole in this variant.

Appropriately, a control unit is provided for a particular load-dependent control and / or control of the drive. As input for the control, for example, the power consumption, the torque or Speed can be used. Also, the strength of the ripple signal can be used as mentioned as a measure of the commutation quality.

Embodiments of the invention will be explained in more detail with reference to a drawing. Showing:

Fig. 1 in an exploded view of an electric motor with rotatable

pole tube,

2 a pole tube with latching connection,

3 a pole tube with section-wise latching connection,

4 shows a pole tube with latching connection to the stator magnet,

Fig. 5 is a pole tube with sections locking connection to the

Stator magnet, Fig. 6 shows the coupling piece of a gear portion for a rotatable

Polrohr, Fig. 7 shows a modified coupling piece of a gear portion for a rotatable pole tube and

Fig. 8 shows the coupling piece of the gear portion of FIG. 7 with attached stator magnet.

From the exploded view according to FIG. 1, an electric motor 1 can be seen, which comprises a gear section 2, a contacting section 3 and an electric machine 4. The gear portion 2 and the contacting portion 3 together form a fixed housing portion 7, on which the electric machine 4 is arranged.

The transmission section 2 comprises a first transmission shell 5 and a second transmission shell 6. A spindle transmission (not shown) is inserted between the transmission shells 5 and 6, the spindle of the spindle transmission being driven via the electric machine 4. On the output side, an actuating element, in this case a side window of a motor vehicle, is electrically actuated. To drive the spindle, the shaft of the electric machine 4 is inserted into the transmission section 2 and rotatably connected to the spindle. The contacting section 3 comprises a receiving tray 8 and a connection cover 9. Between the receiving tray 8 and the connection cover 9, a circuit board 10 is arranged, which carries a control circuit for driving the electric machine 4. About the socket opening 12 of the connection cover 9, the electrical connection of the electric motor first

The electric machine 4 comprises a rotatable armature 13 with invisible armature windings 14. On the receiving tray 8 facing the end of the armature 13, a ball bearing 17 is arranged for storage. The brush commutator 18 can be seen, which carries a number of brush lamellae 20, each of which is electrically contacted with the armature windings 14, on a lamination ring. The brush commutator 18 associated brush 22 are associated with the board 10 and after installation of these in the contacting section 3 structurally connected to the housing 2.3. Upon rotation of the armature 13, the brush blades 20 roll on the contacting brush 22 from.

The electric machine 4 is essentially realized by a movable housing section 23, which is formed as a separate, cylindrical pole tube 25, within which the armature windings 14 of the armature 13 rotate. Also located on the inner side of the pole tube 25 (not visible here) are a number of stator magnets 26, which in the present case are designed as permanent magnets and generate a static external magnetic field.

If the brushes 22 are supplied with a direct current voltage, different brush filaments 20 are successively contacted via the brushes 22 during a rotation of the armature 13, and thus different armature windings 14 are energized one after the other. The armature 13 rotates in the outer, generated by the stator magnet 26 magnetic field at a predetermined speed.

The pole tube 25 is rotatably arranged by means of a rotary coupling 29 on the gear portion 2 and by means of a rotary coupling 30 rotatably mounted on the receiving tray 8. About the clamp 32, the angled with its front Ends on both sides in each case a projection 34 engages behind the gear portion 2, the housing sections 2 and 3 are firmly connected to each other with the interposition of the electric machine 4 and the pole tube 25. In this case, the ball bearing 17 is mounted in a corresponding bearing receptacle of the receiving tray 8. The shaft as an extension of the armature 13 protrudes into the interior of the gear portion 2 for driving the spindle located therein.

The pole tube 25 with the permanently fixed therein magnets 26 is rotatably attached to the housing due to the Drehan couplings 29 and 30 about the armature rotation axis 31. By way of rotation of the pole tube 25, the external static magnetic field can thus be rotated relative to the position of the brushes 22. This allows adaptation of the relative position between the brushes 22 and the overall external magnetic field resulting from superposition with the armature transverse field, so that, given a given running direction of the electric machine 4, a commutation can take place substantially within the then given neutral zone. The brush fire is thus reduced according to the predetermined running direction of the electric machine 4. It will be appreciated that only a single variant, namely the one shown here, must be maintained in order to achieve an adaptation of the magnetic field position for both a left-running and a right-running motor. The pole tube 25 in this case only needs to be rotated in opposite directions.

Schematically further a separate small actuator 40 is shown, which rotates the pole tube 25 last- or speed-dependent during operation of the electric motor. For controlling and / or regulating the drive, a control unit 41 is provided, which may in particular be part of the circuit board 10. As input for the control or regulation, for example, the rotational speed, the torque, the power consumption, the ripple signal of the exciting current or the like is used to obtain a rotation of the pole tube 25, a commutation possible within the neutral zone of the magnetic field. In other words, the pole tube 25 is tracked a migration of the neutral zone, which takes place due to the magnetic reaction of the excitation windings during the operation of the electric machine 4 ,. 2, a variant of the pole tube 25 is shown, wherein at both ends a latching connection is provided to a stepped rotation between the housing sections 2.3. At both ends of the pole tube 25 in this case as a first latching connection part 44, a circumferential toothing 46 is introduced, which meshes with a complementary toothing on the respective housing sections 2.3. About the tooth spacing in this case the adjustable angle of rotation of the pole tube 25 is specified. In the interior of the pole tube 25, the two inserted stator magnets 26 are now clearly visible in FIG.

In Fig. 3, another variant of the pole tube 25 is shown. Compared to the pole tube 25 shown in FIG. 2, the latching connection is now on one side of the gear section 2 facing the end of the pole tube 25 is introduced. The latching connection is realized on the pole tube 25 by means of a first latching connection part 44, which is provided only in sections on the circumference of the pole tube 25. It can be seen with one to the number of teeth 4-fold symmetry in each case a partial toothing 46th

4, a next variant of the pole tube 25 is shown. According to the variant of FIG. 4, a latching connection is realized by the provision of a first latching connection part 44 on the stator magnet 26. On the stator magnet 26 each of the teeth is applied. The toothing 46 shown in FIG. 4 thus meshes concealed in the interior of the pole tube 25 with a corresponding counter-toothing on the gear section 2 or on the contacting section 3.

The pole tube 25 shown in Fig. 5 differs from the pole tube of FIG. 4 only in that now the teeth 46 is only partially applied to the stator magnet 26.

In Fig. 6, the coupling piece of the gear tray 5 is shown, on which the electric machine 4 and the pole tube 25 is placed. It can be seen a flange 50 on which the pole tube 25 is placed. Inside the flange 50 is a central opening 52 can be seen, in which the drive shaft of the electric machine 4 dives.

The flange 50 includes a series of concentric peripheral walls. At the outer periphery of the inner wall lugs 53 are applied, which press against an inner wall of the attached pole tube 25, so that a certain frictional connection and thus a certain stability of the rotary connection to be produced is effected. On the outer circumference of the inner wall is further as part of a latching connection, the second locking connection part 54 can be seen, which is partially formed in the form of a complementary toothing 55. The complementary toothing 55 meshes in particular with the toothing 46 of the pole tubes 25 according to FIGS. 2 and 3.

In Fig. 7, the Kupplungsstϋck a gear section 5 is again shown in a further variant, which serves to receive the electric machine 4 and the pole tube 25. Again, one recognizes a flange 56 having a number of concentric peripheral walls. Again, the lugs 53 are visible on the outer circumference of the inner circumferential wall. Inside, the central opening 52 can be seen, in which the shaft of the electric machine 4 immersed in the installed state.

In contrast to FIG. 6, axially projecting peripheral portions 57 are now attached to the inner circumferential wall. These serve a preset coupling of the pole tube 25 with a specific angular position.

From Fig. 8, the specification of the specific angular position of the attached pole tube 25 can be seen. It can be seen from this illustration that in the installed state, the permanent magnets 26 inserted in the interior of the pole tube 25 are inserted into the gaps between the axially projecting peripheral portions 57. In other words, the preset angular position of the pole tube 25 is achieved in that the axially projecting circumferential portions 57 engage between the inserted permanent magnets 26 of the pole tube 25. If the peripheral portions 57 formed extended in the circumferential direction, so can one of the actual assembly preceding cutting the angle of rotation of the pole tube to be used 25 are set.

LIST OF REFERENCE NUMBERS

1 electric motor 52 central opening

2 Transmission section 53 Nose

3 contacting portion 54 second locking connection part

4 electric machine 55 complementary teeth

5 first gear shell 56 flange

6 second gear shell 57 peripheral portion

7 solid housing section

8 receiving tray

connection cover

10 board

12 socket opening

13 anchors

14 armature windings 7 ball bearings 8 brush commutator 0 brush blades 2 brushes 3 movable housing section 5 pole tube 6 stator magnets 9 rotary coupling 0 rotary coupling 1 rotary axis armature 2 clamping bracket 4 projection 0 drive 1 control unit 4 first locking connection part 6 toothing 0 flange

Claims

claims

An electric motor (1) comprising an armature (13), a brush commutator (18) having a plurality of brushes (22) and a plurality of brush blades (20) associated with the armature (13), having a number of stator magnets (13). 26), and with a housing, in which the armature (13) is rotatably mounted and in which the stator magnets (26) are accommodated, the brushes (22) being associated with the housing in a structurally fixed manner, characterized in that a fixed housing section (7 ) and a relative to the fixed housing portion (7) about the rotational axis (31) of the armature (13) rotatable movable housing portion (23) are provided, wherein the movable housing portion (23) associated with the stator magnets (26).

2. Electric motor (1) according to claim 1, characterized in that the fixed housing portion (7) comprises a gear portion (2) and a contacting portion (3), wherein the movable housing portion (23) rotatably between the transmission (2) and the Contacting section (3) is mounted.

3. Electric motor (1) according to claim 1 or 2, characterized in that the movable housing portion (23) by means of a step-adjustable locking connection rotatably mounted on the fixed housing portion (7), wherein the latching connection, a first locking connection part (44), which the movable Housing section (23) is assigned, and a second Locking connection part (54) which is associated with the fixed housing portion (7) comprises.

4. Electric motor (1) according to claim 3, characterized in that the first latching connection part (44) along the circumference of the movable housing portion (23) is arranged.

5. Electric motor (1) according to claim 3, characterized in that the first latching connection part (44) is arranged on the stator magnet (26).

6. Electric motor (1) according to one of claims 3 to 5, characterized in that at least one of the latching connection parts (44,54) is formed only partially in the circumferential direction.

7. Electric motor (1) according to one of claims 2 to 6, characterized in that the movable housing portion (23) is connected at both ends by means of snap-in connections (44,54) with the gear portion (2) and with the contacting portion (3).

8. Electric motor (1) according to one of claims 2 to 6, characterized in that the latching connection (44,54) is formed on one side between the movable housing portion (23) and the transmission portion (2).

9. Electric motor (1) according to one of claims 3 to 8, characterized in that the latching connection parts (44,54) are formed as mutually complementary toothings (46,55).

10. Electric motor (1) according to one of claims 3 to 8, characterized in that the latching connection by means of intermeshing Umfangsabschnit- te (57) of the fixed housing portion (7) and the movable housing portion (23) is formed.

11. Electric motor (1) according to claim 10, characterized in that the peripheral portions (57) for achieving a specific rotational position of the movable housing portion (23) are formed type-specific.

12. Electric motor (1) according to claim 10 or 11, characterized in that circumferential portions (57) of the gear housing (2,3) between the stator magnets (26) in the movable housing portion (23) engage.

13. Electric motor (1) according to claim 1 or 2, characterized in that the movable housing portion (23) via a rotary coupling to the fixed housing (2,3) is connected.

14. Electric motor (1) according to claim 13, characterized in that a controllable drive (40) is provided for actuating the rotary coupling.

15. Electric motor (1) according to claim 13, characterized in that a control unit (41) is provided for a particular load-dependent control and / or control of the drive.

16. Electric motor (1) according to one of the preceding claims, characterized in that the movable housing portion (23) is formed as a separate pole tube (25) on which the stator magnets (26) are arranged.