EP1997212A1

EP1997212A1 - Electrical machine

Info

Publication number: EP1997212A1
Application number: EP07703912A
Authority: EP
Inventors: Achim Hawighorst
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-03-14
Filing date: 2007-01-16
Publication date: 2008-12-03
Also published as: WO2007104589A1; US20090236928A1; KR20080108458A; CN101401281A; DE102006011601A1; BRPI0708892A2; JP2009529853A

Abstract

The invention describes an electrical machine comprising an armature (20) with armature slots (24) for accommodating armature coils and a commutator (10) with commutator laminates (11), wherein at least one armature coil is formed from two coil elements (25, 26), which are arranged symmetrically with respect to one another in relation to the axis of rotation (21) of the armature (20). The electrical machine is characterized in that the number of commutator laminates (11) is an integral multiple of the number of armature slots (24).

Description

description

title

Electric machine

State of the art

The invention relates to an electrical machine, in particular a DC machine, according to the preamble of claim 1.

WO 2005/076442 A discloses an electric motor with a symmetrically arranged armature winding. The symmetrically arranged armature winding consists of a first coil which is wound between any two Ankernuten and is electrically contacted on adjacent Kommutatorlamellen. A second coil is wound between two armature slots, which are in point-symmetrical position with respect to the center point of the armature shaft relative to the two armature slots of the first coil and are wound in the opposite direction. In the engine, the number of Ankernuten is the same

Number of commutator bars. The engine has a brush for high and low speeds and a common brush. The first and second spools are arranged to be in a symmetrical position with respect to a center passing through the center of the high-speed brush and the center of the rotary shaft when the high-speed brush comes in contact with the adjacent commutator fin and thereby first coil is shorted to the second coil.

Disclosure of the invention

The electrical machine according to the invention with the features of claim 1 has an improved noise reduction and improved electromagnetic compatibility (EMC). This is achieved in that the electric machine according to the invention comprises an armature winding of armature coils, wherein at least one armature coil of two symmetrically arranged with respect to the axis of rotation of the armature Part coils is constructed. This means that the armature coils are formed so that in each case two partial coils are arranged symmetrically with respect to the axis of rotation of the armature. According to the invention, the number of commutator bars is an integer multiple of the number of armature slots. The number of Kommutatorlamel- len is in particular at least twice as large as the number of Ankernuten. Preferably, the number of commutator bars is twice as large as the number of armature slots. However, the number of lamellae may also be, for example, three times the number of armatures. In addition, the commutator preferably has an even number of commutator bars.

According to the invention, the two partial coils are arranged symmetrically with respect to one another such that when the partial coils are energized in a magnetic field, substantially no radial forces act on the armature. The two partial coils can be commutated at the same time, for example by being connected to adjacent commutator segments. The resulting radial forces are compensated particularly well by the fact that the two

Part coils are arranged substantially geometrically parallel to each other and at the same distance from the axis of rotation of the armature. In addition, the radial forces can be compensated particularly well by the fact that the two sub-coils have the same number of turns. The radial forces can also be compensated particularly well by the two sub-coils are wound in opposite directions to each other. The two partial coils arranged symmetrically to one another are also referred to below as a partial coil pair. In particular, it is a two-pole electrical winding.

The two symmetrically arranged partial coils are preferably wound in the manner of the ternary winding, but may also be wound in the manner of the diameter winding.

In a multiple Kommutatorlamellenzahl a corresponding number of partial coils is wound in each case a Ankernut. For example, with twice the number of lamellae, there are two partial coils (one partial coil each of a partial coil pair) or three partial coils (likewise each one partial coil of a partial coil pair) in an armature groove when the number of lamellae is three times. This means that two or three partial coils of two or three partial coil pairs are arranged in an armature core. For a given groove surface, this can be achieved, for example, by a correspondingly smaller number of turns per partial coil or a smaller coil wire cross-section be, with the former is associated with a change in speed, the latter with a change in performance.

The two sub-coils of a partial coil pair can either be connected electrically in series or parallel to one another. In the series connection, the two partial coils have two ends, which are electrically connected to one commutator each. If twice the number of commutator bars is provided, the two ends of the two series-connected partial coils are each electrically connected to the next-but-one commutator bar. Thus, for example, the first end of a first partial coil pair is connected to a first commutator and the second end of the first partial coil pair connected to the next but one, so the third, commutator. The intermediate second commutator bar is connected to the first end of a second partial coil pair, while the second end of the second partial coil pair is in turn connected to the next but one, here the fourth, commutator bar. This combination of the two ends of a series-connected partial coil pair continues accordingly until all armature slots are occupied by symmetrically arranged partial coils. With a threefold number of commutator bars, the two ends of the series-connected partial coils are each electrically connected to the third commutator bar in an analogous manner. This means that, for example, the first end of a first partial coil pair with a first commutator and the second

End of the first coil pair is connected to the fourth commutator. Accordingly, the first end of a second partial coil pair is connected to the second commutator fin, the second end of the second partial coil pair is connected to the fifth commutator fin. Furthermore, the first end of a third partial coil pair is connected to the third commutator fin, the second end of the third partial coil pair is connected to the sixth commutator fin.

In the case of the parallel connection, on the other hand, each of the two partial coils of a partial coil pair has two ends, so that four ends per partial coil pair are electrically conductively connected to the commutator lamellae. With a doubled number of commutator bars, the ends of the two sub-coils are alternately connected to adjacent commutator bars. This means that the second end of a partial coil is connected to the next but one Kommutatorlamelle. Accordingly, for example, the first end of a first partial coil with a first commutator and the second end of the first coil part connected to the next but one, ie the third, commutator, while the first end of the second sub-coil is connected to the second commutator and the second end of the second sub-coil to the fourth Kommutatorlamelle.

The electric machine according to the invention has at least two brushes which slidably rest against the commutator. The two brushes are e.g. opposite each other. In order to ensure the most uniform possible flow of current in the commutation, the brush width is selected such that during the rotation of the commutator in each case the fins to which the two coil sections are connected, are short-circuited. However, it may also have a different brush width, e.g. 1, 2 times the width of a commutator bar.

In the electric machine according to the invention may also be provided for speed setting, a third brush, which is radially between the opposing brushes (hereinafter referred to as the first and second brush) is arranged. Thus, the third brush is less than 180 ° to the first brush in the direction of rotation by a certain angle, e.g. 70 °, offset. At this time, in the low speed stage, the two opposing brushes, i. the first and second brush, energized, while the third brush is de-energized. In the high speed stage, the second and the third brush are energized, whereas the first brush is de-energized. The second brush thus forms the common brush, which cooperates at low speeds with the first brush and at high speeds with the third brush.

In a further preferred embodiment, the symmetrically arranged partial coils are designed as double windings with reduced, e.g. formed with the half, coil wire cross section in two layers. As a result, an increased Nutfüllfaktor can be achieved.

The electrical machine according to the invention may be, for example, a two-pole DC motor for adjusting movable components in the motor vehicle, such as e.g. a windscreen wiper motor, window lift motor, seat adjustment motor.

The invention will be explained in more detail with reference to the accompanying drawings. Show it:

Fig. 1 shows an electric machine with two brushes Fig. 2 shows a first embodiment of armature coils with two symmetrical partial coils with tendon winding in series

Fig. 3 shows a second embodiment of armature coils with two symmetrical partial coils with tendon winding in parallel

4 shows a third embodiment of armature coils with two symmetrical partial coils with a diameter winding

Fig. 5 shows a fourth embodiment with three times the number of commutator bars.

In Fig. 1, an electrical machine 100 is shown, which has an armature 20, two magnetic pole 30 and a commutator 10 with Kommutatorlamellen 11. The armature 20 and the commutator 10 are rotatably mounted on an armature shaft 22 having a rotation axis 21. First and second brushes 14 slidably face each other on the commutator 10.

FIG. 2 schematically shows a partial development of a first embodiment of armature coils, each having two symmetrical partial coils. In the illustrated embodiment, the commutator 10 has 24 lamellae 11 and the armature 20 has twelve teeth 23 and twelve armature slots 24. The armature coil is wound in the manner of a loop winding in the form of a chord winding. A first partial coil pair 25, 26 is wound as follows: The winding of a first partial coil 25 is located in a first anchor groove 24 between the twelfth and first teeth 23 and the sixth anchor groove 24 between the fifth and sixth teeth 23. The winding of a second partial coil 26 is located in the twelfth Ankernut 24 between the eleventh and twelfth tooth 23 and the seventh Ankernut 24 between the sixth and seventh tooth 23. The two ends of the first and second part coil 25, 26 are connected to the next but one (here the third and fifth) commutator 11th electrically connected. The two partial coils 25, 26 are therefore connected in series. The first and sixth Ankernut 24 and the seventh and twelfth Ankernut 24 are opposite to each other, so that the two sub-coils 25, 26 are arranged symmetrically with respect to the axis of rotation 13 of the armature 20. The partial coils 25, 26 run parallel to one another, the two partial coils 25, 26 being wound in the opposite direction. are wrapped in a sense. In the illustrated embodiment, first the first partial coil 25 is wound before the second partial coil 26 is wound. Alternatively, however, the two partial coils 25, 26 are alternately wound.

A first partial coil 25 'of a second partial coil pair 25', 26 'is also located in the first and sixth armature groove 24, the second partial coil 26' of the second partial coil pair 25 ', 26' lies in the twelfth and seventh Ankernut 24. The two ends are in turn each connected to the next but one Kommutatorlamelle 11, wherein the first end of the second coil sub-pair is here tatorlamelle 11 connected to the fourth, the second end with the sixth commutator. Accordingly, the other armature slots 24 are each occupied by two first partial coils 25 or second partial coils 26 of two partial coil pairs 25, 26, the two ends of a partial coil pair 25, 26 each having the next but one Kommutatorlamelle 11 (eg the third and fifth, and the fourth and sixth ) connected is. This means that the four ends of two coil pairs 25, 26 and 25 ', 26', which lie in the same Ankernuten 24, alternately with one each

Commutator blade 11 are connected.

In Fig. 3 is a partial development of a second embodiment of armature coils, each with two symmetrical partial coils 25, 26 and 25 ', 26' of two partial coil pairs shown schematically. In the illustrated embodiment, in turn, the commutator 10 has 24 lamellae 11 and the armature 20 has twelve teeth 23 and twelve armature slots 24. The armature coil is likewise wound in the manner of the loop winding in the form of a chord winding. The winding of a first partial coil 25 of a first partial coil pair 25, 26 is located in the second anchor groove 24 between the first and second teeth 23 and the seventh anchor groove 24 between the sixth and seventh teeth 23. The winding of a second partial coil 26 of the first partial coil pair 25, 26th is located in the first anchor groove 24 between the twelfth and first tooth 23 and the eighth anchor groove 24 between the seventh and eighth tooth 23. The two sub-coils 25, 26 are connected in parallel by the two ends of each sub-coil 25, 26, each with the next but one Kommutatorlamelle 11 are electrically connected. That is, in FIG. 3, the first end of the first sub-coil

25 with the sixth fin 11, the second end of the first part coil 25 with the eighth fin 11 and the first end of the second part coil 26 with the seventh fin 11, the second end of the second part coil 26 is connected to the ninth fin 11. Accordingly, the four ends of the partial coil pair 25, 26 are alternately connected to adjacent commutator fins 11. The first partial coil 25 'of a second partial coil pair 25 ', 26' is in the same Ankernuten 24 as the first part coil 25 of the first coil subgroup 25, 26, but the coil ends of FIG. 3 with the seventh and ninth Kommutatorlamelle 11 are electrically connected. Accordingly, the second partial coil 26 'of the second partial coil pair 25', 26 'is wound in the same armature slots 24 as the second partial coil 26 of the first partial coil pair 25, 26. Their first and second ends are connected to the sixth and eighth commutator blades 11.

FIG. 4 schematically shows a partial development of a first embodiment of armature coils, each having two symmetrical partial coils. In the illustrated embodiment, the commutator 10 has 24 fins 11 and the armature 20 has twelve teeth

23 and twelve armature slots 24. The armature coil is wound in the manner of the loop winding in the form of a diameter winding. A first partial coil pair 25, 26 is wound as follows: The winding of a first partial coil 25 lies in a first armature groove 24 between the twelfth and first tooth 23 and in the seventh armature groove 24 between the sixth and seventh tooth 23. The winding of a second partial coil 26 is also in the first anchor groove 24 between the twelfth and first tooth 23 and the seventh anchor groove 24 between the sixth and seventh tooth 23. The two ends of the first and second coil sections 25, 26 are with the next but one (here the sixth and eighth) Commutator blade 11 electrically connected. The two partial coils 25, 26 are therefore connected in series. In the illustrated embodiment, first the first sub-coil 25 is wound before the second sub-coil 26 is wound. Alternatively, however, the two partial coils 25, 26 are alternately wound.

A first partial coil 25 'and the second partial coil 26' of a second partial coil pair 25 ', 26' are also in the first and seventh Ankernut 24. The two ends are in turn connected to each of the next but one Kommutatorlamelle 11, wherein the first end of the second partial coil 25th ', 26' is connected to the seventh, the second end to the ninth Kommutatorlamelle 11. Accordingly, the other armature slots 24 are each occupied by two first partial coils 25 or second partial coils 26 of two partial coil pairs 25, 26, the two ends of a partial coil pair 25, 26 each having the next but one Kommutatorlamelle 11 (eg the third and fifth, and the fourth and sixth ) connected is. This means that the four ends of two partial coil pairs 25, 26 and 25 ', 26', which lie in the same armature slots 24, are alternately connected to one commutator blade 11 each. In the embodiment according to FIG. 5, a partial development of armature coils, each with two symmetrical partial coils, is shown schematically, in which the commutator 10 has 24 lamellas 11 and the armature 20 has eight teeth 23 and eight armature slots 24. Accordingly, the number of commutator bars 11 is three times the number of armature slots 24. The armature coil is wound in the form of a chord winding in the manner of the loop winding. A first partial coil pair 25, 26 is wound as follows: The winding of a first partial coil 25 is located in a first anchor groove 24 between the eighth and first teeth 23 and the fourth anchor groove 24 between the third and fourth teeth 23. The winding of a second partial coil 26 is located in the eighth anchor groove 24 between the seventh and eighth teeth 23 and the fifth anchor groove 24 between the fourth and fifth teeth 23. The two ends of the first and second sub-coils 25, 26 are connected to the third (here the third and sixth) commutator segments 11 electrically connected. The two partial coils 25, 26 are therefore connected in series. Analogous to the embodiment shown in FIG. 2, the armature slots 24, in which the first partial coil 25 is wound, and the armature slots 24, in which the second partial coil 26 is wound, face each other. The two sub-coils 25, 26 are arranged symmetrically with respect to the axis of rotation 13 of the armature 20 by running parallel to each other, wherein the two sub-coils 25, 26 are wound in the reverse sense. In the illustrated embodiment, first the first sub-coil 25 is wound before the second sub-coil 26 is wound. Alternatively, however, the two partial coils

25, 26 can be wound alternately.

A first partial coil 25 'of a second partial coil pair 25', 26 'is also located in the first and fourth armature 24, the second partial coil 26' of the second partial coil pair 25 ', 26' is also in the eighth and fifth Ankernut 24. The two ends in turn connected in each case to the third commutator lamella 11, the first end of the second partial coil pair 25 ', 26' being connected here to the fourth, the second end to the seventh commutator lamella 11.

A first partial coil 25 'of a third partial coil pair 25 ", 26" also lies in the first and fourth armature groove 24, the second partial coil 26' of the third partial coil pair 25 ", 26" also lies in the eighth and fifth armature groove 24. The two ends are in turn connected in each case to the third commutator plate 11, wherein the first end of the third partial coil pair 25 ", 26" is here connected to the fifth, the second end to the eighth commutator plate 11. Accordingly, the other Ankernuten 24 each with three first coil sections 25, 25 ', 25 "or second coil sections 26, 26', 26" three coil pairs 25, 26, 25 ', 26' and 25 ", 26" occupied, wherein the both ends of a partial coil pair 25, 26, 25 ', 26' or 25 ", 26" with each of the next but one Kommutatorlamelle 11 (eg the third and sixth, the fourth and seventh, and the fifth and eighth) is connected. This means that the four ends of two partial coil pairs 25, 26 and 25 ', 26', which lie in the same armature slots 24, are alternately connected to one commutator blade 11 each.

2, 3, 4 and 5 each show an embodiment of a series connection and a parallel connection of the two partial coils 25, 26. According to the illustrated principle of the winding of two symmetrically arranged partial coils 25, 26 many other winding schemes can be realized.

Claims

claims

1. An electric machine comprising an armature (20) with Ankernuten (24) for receiving armature coils and a commutator (10) with Kommutatorlamellen (11), wherein at least one armature coil of two partial coils (25, 26) is formed, which respects the axis of rotation (21) of the armature (20) are arranged symmetrically to each other, characterized in that the number of Kommutatorlamellen (11) is an integer multiple of the number of Ankernuten (24).

2. Electrical machine according to claim 1, characterized in that the number of Kommutatorlamellen (11) is at least twice as large as the number of Ankernuten (24).

3. Electrical machine according to one of claims 1 or 2, characterized in that the two partial coils (25, 26) are arranged substantially geometrically parallel to each other.

4. Electrical machine according to one of the preceding claims, characterized in that the two partial coils (25, 26) have the same number of turns.

5. Electrical machine according to one of the preceding claims, characterized in that the two partial coils (25, 26) are wound in the reverse sense of winding.

6. Electrical machine according to one of claims 1-5, characterized in that the two partial coils (25, 26) are electrically connected in series.

7. Electrical machine according to one of claims 1-5, characterized in that the two partial coils (25, 26) are electrically connected in parallel.

8. Electrical machine according to one of the preceding claims, characterized in that at least two brushes (14) slidably rest on the commutator (10).

9. Electrical machine according to claim 8, characterized in that three brushes (14) slidably abut the commutator (10).