CN110832749B

CN110832749B - Electric motor with brush holder formed by leaf spring element

Info

Publication number: CN110832749B
Application number: CN201880044328.XA
Authority: CN
Inventors: 赫尔穆特·普法尔茨格拉夫
Original assignee: Brose Bamberg Co ltd
Current assignee: Brose Bamberg Co ltd
Priority date: 2017-07-28
Filing date: 2018-07-25
Publication date: 2022-05-17
Anticipated expiration: 2038-07-25
Also published as: CN110832749A; DE102017213083A1; WO2019020660A1

Abstract

The electric motor (1) comprises a stator (10), a rotor (11) which can be rotated relative to the stator (10), a commutator (13) which is operatively connected to the rotor (11) and can be rotated together with the rotor (11), a carrier element (16) which is fixed in position relative to the stator (10), a brush holder (15) which is arranged on the carrier element (16), and brushes (14) which are arranged on the brush holder (15) and which are in electrical contact with the commutator (13). The brush holder (15) is formed by a leaf spring element having an abutment section (150) which abuts against the carrier element (16), a retaining section (152) which carries the brushes (14), and a connecting section (151) which connects the abutment section (150) and the retaining section (152) to one another in one piece and which is bent both relative to the abutment section (150) and relative to the retaining section (152). In this way, an electric motor is provided which has a brush holder which is of simple construction, can be produced in a simple manner and can also be mounted in a simple manner.

Description

Electric motor with brush holder formed by leaf spring element

Technical Field

The present invention relates to an electric motor.

Background

The electric motor comprises a stator, a rotor which can rotate relative to the stator, a commutator which is operatively connected to the rotor and can rotate with the rotor, and a carrier element which is fixed in position relative to the stator. A brush holder is arranged on the carrier element, on which brush holder brushes are held, which contact the commutator in an electrically contacting manner.

In such brush-commutated (dc) motors, a winding in the form of a coil is arranged on the rotor and is wound for this purpose, for example, around the teeth of the core of the rotor. The coil is in electrical contact with the lamellae of the commutator, so that the coil can be energized via the commutator during operation of the electric motor. The current supply takes place here via one or more brushes, for example 2, 4 or 6 brushes, which come into contact with the commutator in electrical contact and supply the one or more windings of the rotor in a commutated manner as a function of which sheet each brush comes to bear during the rotation of the rotor. By means of the magnetic field generated on the coils and by means of the interaction with the excitation field of the permanent magnets arranged azimuthally on the stator, a torque is generated on the rotor and the rotor is thereby twisted.

In such electric motors, the brushes are typically held in an energized and spring-loaded manner on a brush holder. When the electric motor is installed, it is ensured that the brushes slide onto the commutator in a positionally correct manner and are pressed radially outward to enable the brushes to be pushed onto the commutator axially (along the rotational axis of the electric motor).

There is generally a need for a brush holder that can be manufactured simply and inexpensively in order to reduce the cost of an electric motor.

In the electric motor known from EP 0474904B 1, the brushes are arranged movably on a brush holder and are in contact with a commutator arranged on the shaft of the electric motor.

In the electric motor known from EP 0482234 a1, a brush hold-down spring made of a one-piece wire is bent and bears with one end against the brush and with the other end against the bearing cap.

Disclosure of Invention

The object of the present invention is to provide an electric motor having a brush holder which is of simple construction, can be produced in a simple manner and can also be mounted in a simple manner.

This object is achieved by an electric motor having the features of the invention.

The brush holder is therefore formed by a leaf spring element having an abutment section which abuts against the carrier element, a retaining section which carries the brushes, and a connecting section which connects the abutment section and the retaining section to one another in one piece and which is bent both relative to the abutment section and relative to the retaining section.

The brush holder is therefore formed by a leaf spring element which carries a brush which is arranged for this purpose on the holding section and which is fixed to the carrier element. The leaf spring element is elastic and is formed in one piece with its contact section, holding section and connecting section, so that a component is provided which can be produced and installed in a simple manner and which implements a brush holder.

For mounting, the brush holder is fixed with its contact section to the carrier element, wherein the contact section in the mounted state contacts the upper side of the carrier element in a face-down manner and is thereby held in a defined position on the carrier element. The brushes are held on the holding section and, in the installed electric motor, contact the commutator of the electric motor under spring-elastic pretension. The connecting section, which is bent both against the contact section and against the retaining section, produces an advantageous spring loading that pretensions the brushes against the commutator.

Preferably, the connecting section has a first acute angle with respect to the retaining section and a second acute angle with respect to the abutment section. Thus, on the one hand, the angle between the connecting section and the contact section is less than 90 ° and, on the other hand, the angle between the connecting section and the retaining section is less than 90 °. In the installed state of the electric motor, at least one angle, preferably both angles, are smaller than in the unloaded state of the brush holder formed by the leaf spring element, so that the brushes are pressed elastically against the commutator on the contact section by this stress in the brush holder.

In one embodiment, the connecting section is bent at the first bending edge in a first bending direction relative to the contact section, and the holding section is bent at the second bending edge in a second, opposite bending direction relative to the connecting section. The leaf spring element forming the brush holder has a conventional zigzag shape in this way, wherein the retaining section and the contact section can extend at least approximately parallel to one another or can also extend at an angle to one another.

If the contact portion and the holding portion extend at least approximately parallel to one another, a Z-shape of the brush holder is obtained, which enables an at least approximately linear adjustability of the brush perpendicular to the plane of the contact portion and the holding portion, which facilitates the contact of the brush on the commutator.

In one embodiment, the brush is inserted into an opening of the holding section and is thereby fixed to the holding section. For example, the brush may be inserted into an opening of the holding section with a plug section protruding from the body, and may be compressively held between clamping plates protruding from the holding section. The clamping plate is cut out of the holding section and bent relative to the holding section, for example, and is formed in one piece with the holding section in this way.

The brush may for example constitute a solid piece made of graphite, for example. The brush is in electrical contact with the commutator, wherein the brush, as a result of the arrangement on the retaining section, is in contact with the brush holder and is electrically connected via the brush holder to a contact point of a circuit board, which serves as a carrier element, for example.

In one embodiment, the brush rests with a contact surface facing away from the holding section against an outer circumferential side of the commutator. The electrical contact with the commutator is established via a contact surface, wherein the brush can be curved concavely on the contact surface, for example, in order to advantageously rest on the cylindrical commutator.

During operation of the electric motor, material wear usually occurs on the brushes as a result of the brushes rubbing against the commutator. In operation, the contact surfaces of the brushes are thus matched to the surface curvature of the commutator by means of a slip-grinding process, so that during operation a surface-contact is obtained between the brushes and the outer circumferential side of the commutator. This process is also known as break-in (Einlaufen).

In order to achieve advantageous running-in behavior, it can be provided that, in the initial state, before the electric motor is put into operation, the brushes have a different curvature at the contact surfaces than the outer circumferential side of the commutator. The curvature of the contact surface can therefore be greater than the curvature of the outer circumferential side surface in such a way that the contact surface has a first radius of curvature (relative to the axis of rotation of the rotor of the electric motor) which is smaller than a second radius of curvature of the outer circumferential side surface of the commutator. In the case of a start-up operation of the electric motor, the brush is therefore initially only in contact with the commutator at the outer edges of the contact surfaces, so that wear-free material on the contact surfaces is initially present mainly at these outer edges during the start-up operation, until the contact surfaces are adjusted in their shape by the sliding contact with the circumferential side of the commutator, so that a full contact is present between the contact surfaces and the circumferential side of the commutator.

In one embodiment, the contact section of the brush holder, which forms the leaf spring element, is in surface contact with a carrier element, which can be realized, for example, by a circuit board and conductor tracks arranged on the circuit board. The brush holder is in electrical contact with at least one contact point of the carrier element, so that a current flow via the brush holder to the brushes can be achieved in order to commutate the windings on the rotor.

In one embodiment, the brush holder has at least one contact pin arranged on the contact section, which, when the brush holder is mounted, engages in an associated contact opening of the carrier element and is electrically contacted to the carrier element by the engagement and, for example, an additional soldered connection. For example, two contact pins can be formed on the contact section, each of which engages in a contact opening of the carrier element and makes electrical contact with the carrier element. On the one hand, a mechanical connection of the contact section to the carrier element is established via the contact pin, and on the other hand, an electrical contact of the brush holder is made via the contact pin.

The contact pin is preferably formed integrally with the contact section and is for this purpose, for example, cut free from the contact section and bent in a bent manner relative to the contact section. In order to enable the contact portion to be in surface contact with the carrier element, the contact pin is first bent away from the carrier element, for example from the end connected to the contact portion, so that the bent portion protrudes from the carrier element. The pin section connected to the curved section then extends perpendicularly through the associated opening of the contact section, from which the contact pin is cut out freely, so that the pin section points perpendicularly to the contact section and engages with the associated contact opening of the carrier element.

The brush holder itself is spring-elastic, wherein elastic deformation preferably takes place at the bending edge in order to bend the connecting section on the one hand relative to the contact section and on the other hand relative to the retaining section.

In this case, it is conceivable and possible to provide additional damping on the brush holder by the damping element acting in a damped manner between the contact section and the connection section and/or between the connection section and the retaining section.

In one embodiment, a damping element, for example in the form of a wad made of viscoelastic material, can be installed in the region of the bending edge between the contact section and the connecting section or between the connecting section and the retaining section. In this way, the elastic movement of the individual segments of the brush holder relative to one another is damped in a viscoelastic manner.

According to a further aspect, the brush holder has a stop element for limiting the adjustment travel of the holding section. The stop element is also preferably integrally formed on the brush holder, for example on an abutment section of the brush holder. The stop element can be formed, for example, by a rod section cut out freely from the abutment section, which extends perpendicularly to the abutment section and projects therefrom in the direction of the retaining section. In this case, a stop lug can be formed on the end of the lever section remote from the contact section, for example by bending, which stop lug limits the movement of the holding section relative to the contact section. This makes it possible to simplify the assembly of the electric motor by holding the brushes arranged on the holding section via the stop element in a radially outer position close to the contact section, in which position the axial pushing of the brushes onto the commutator can be achieved. In the context of assembly, the additional measure of pressing the brushes radially outward to slide them onto the commutator can therefore be eliminated if necessary.

Drawings

The idea underlying the invention is explained in detail below with the aid of embodiments shown in the drawings. Wherein:

fig. 1 shows a schematic view of an electric motor;

FIG. 2 shows another view of the electric motor;

FIG. 3 shows a view of an embodiment of a brush holder consisting of a leaf spring element;

FIG. 4 shows a view of another embodiment of a brush holder;

FIG. 5 shows a view of yet another embodiment of a brush holder;

FIG. 6 shows a view of yet another embodiment of a brush holder; and is

Fig. 7 shows a schematic view of the brush together with the commutator.

Detailed Description

Fig. 1 and 2 show in a schematic view an exemplary embodiment of a drive device which can be used, for example, as a window lift drive for adjusting a window pane in a vehicle in the form of an electric motor. The drive device can be installed, for example, in the door interior of a side door of a vehicle in order to adjust a window pane guided on one or more guide rails via a transmission element 24 in the form of a pull cord for opening or closing a window opening.

The drive device has an electric motor 1 which forms a dc motor rectified by brushes. The electric motor 1 comprises a stator 10 which is arranged fixedly in or on a housing 18 relative to the housing, relative to which stator the rotor 11 connected to the motor shaft 12 is rotatably supported such that the rotor 11 can rotate about a rotational axis D1 relative to the stator 10 during operation of the electric motor 1.

A commutator 13 is arranged on the motor shaft 12, which commutator rotates together with the rotor 11 about the axis of rotation D1 during operation of the electric motor 1. As is evident from the schematic illustration according to fig. 7, commutator 13 has lamellae 131 in a manner known per se, which lamellae 131 are arranged on a cylindrical outer circumferential side 130 of commutator 13 and are electrically separated from one another. As is evident from the schematic representation according to fig. 2, brush 14 bears in electrical contact with lamellae 131, so that electrical contact is provided via brush 14 to the windings arranged on rotor 11 in order to energize the windings in a rectified manner for providing a torque on rotor 11.

The brushes 14 are fixed via a brush holder 15 to a carrier element 16 in the form of a printed circuit board arranged azimuthally fixed in a housing 18 and are in electrical contact with associated contact points of the carrier element 16 in order to provide a through-current to the respectively contacting windings of the rotor 11 via the brush holder 15.

The transmission 2 is driven via the electric motor 1 in order to transmit the torque of the electric motor 1 towards a driven element 23 (in the exemplary embodiment shown, a rope drum) and thus onto a transmission element 24. For this purpose, a drive worm 20 is arranged on the motor shaft 12, which drive worm meshes with an external toothing of a drive wheel 21 via a worm toothing. The drive gear 21 is rotatable about a rotational axis D2 and is connected via a shaft 22 to a driven element 23 in the form of a rope drum, so that a rotational movement of the drive gear 21 is transmitted into a rotational movement of the driven element 23. When the driven element 23 is rotated, the transmission element 24 in the form of a pull cord is wound, for example, with one end onto the driven element 23 and unwound with the other end from the driven element 23, so that a movement of the transmission element 24 and thus a setting force for setting, for example, a window pane is obtained in a known manner.

The electric motor 1 is enclosed in a housing 18, as is schematically shown in fig. 1, and is arranged on a carrier element 3, for example in the form of an assembly carrier of a door module. As is apparent from fig. 1, the rotation axis D1 of the electric motor 1 is directed obliquely at an acute angle to a plane perpendicular to the rotation axis D2 of the drive gear 21. This can be advantageous in an advantageous manner in order to make full use of the available installation space and to provide a drive which is constructed compactly.

The brush holder 15 is arranged on the carrier element 16 and held in a fixed position in the housing 18. The carrier element 16 extends, for example, parallel to the plane of rotation of the drive gear 21, i.e. perpendicular to the axis of rotation D2 of the drive gear 21, and is fastened in the housing 18.

Fig. 3 shows a first exemplary embodiment of a brush holder 15, which has brushes 14 arranged thereon. The brush holder 15 is formed by a leaf spring element and is made of, for example, spring steel. The brush holder 15 has an abutment section 150 which abuts the carrier element 16 in a surface-mounted manner and is in electrical contact with the carrier element 16. The connecting section 151 is bent relative to the contact section 150 about a first bending edge 155, the retaining section 152 is connected to the connecting section, and the retaining section is bent relative to the connecting section 151 about a second bending edge 156. The brush 14 is fixed to the holding section 152.

In the illustrated embodiment, the brush holder 15 has a zigzag shape. Accordingly, the connecting section 151 is bent at the first bending edge 155 in the first bending direction B1 relative to the contact section 150, while the retaining section 152 is bent at the second bending edge 156 in the opposite second bending direction B2 relative to the connecting section 152.

Since the brush holder 15 is designed from a leaf spring element, the brush holder 15 itself is elastic. In the mounted state, the brush 14 rests with a contact surface 140 against an outer circumferential side 130 of the commutator 13 under elastic pressing pressure, wherein the brush 14 is optionally elastically readjusted due to the elasticity in the brush holder 15.

The brush 14 is mechanically held on the holding portion 152 in that the brush 14 is inserted with a plug portion 142 protruding from the body 140 and facing away from the contact surface 140 into an opening 154 in the holding portion 152. The body 140 is braced with a step on the upper side of the holding section 152 and extends with the plug section 142 through the opening 154, wherein the plug section 142 is held clamped between clamping plates 154A cut out freely from the holding section 152 and bent perpendicular to the plane of extension of the holding section 152. In this way, the brush 14 is fixed to the holding section 152.

Two contact pins 153 are formed on the contact portion 150, which are cut free from the contact portion 150 and are therefore integrally connected to the contact portion 150. The contact pins 153 are each bent from an end 153A connected to the contact portion 150, first away from the carrier element 16 (on the surface 160 of which the contact portion 150 rests in a planar manner), and project from the carrier element 16 with a bent portion 153B. The pin section 153C extends from the bending section 153B downward in the direction of the carrier element 16 and extends through the respectively associated contact opening 161 in the carrier element 16.

The contact pin 153 is cut out of the contact section 150 and is bent relative to the contact section 150 in such a way that the pin section 153C extends through an opening 153D formed in the contact section 150.

The contact portion 150 is mechanically fixed to the carrier element 16 via two contact pins 153, and is fixed in the contact openings 161, for example via a soldered connection. Furthermore, an electrical contact with the associated contact point of the carrier element 16 is established via the contact pin 153, so that a current can flow through the brush holder 15 and through the brushes 14. Since the contact pin 153 is bent at its end 153A connected to the contact portion 150 away from the carrier element 16 and projects with the bent portion 153B from the carrier element 16, a planar contact of the contact portion 150 on the surface 160 of the carrier element 16 can be achieved without this being impeded by the bent edge on the contact pin 153.

In the embodiment shown in fig. 4, which differs from the embodiment according to fig. 3, the retaining section 152 extends substantially parallel to the contact section 150. A Z-shape is obtained in which the brushes are adjusted substantially linearly in the adjustment direction V when the brush holder 15 is adjusted elastically, which may facilitate the abutment of the brushes on the commutator 13.

As in the exemplary embodiment according to fig. 4, the connecting section 151 has a first acute angle α with respect to the retaining section 152 and a second acute angle β with respect to the contact section 150. In the exemplary embodiment according to fig. 4, these angles α, β are substantially equally large, whereas in the exemplary embodiment according to fig. 3, these angles are not equally large, so that a tilting of the brush 14 relative to the contact portion 150 is obtained, as is evident from fig. 3.

Fig. 4 shows a recess 157 in the form of a window in the connecting section 151, into which the brush 14 can be lowered with the plug section 142 when the brush 14 is adjusted in the direction of the contact section 150, which increases the possible adjustment travel of the brush 14 in the direction of the contact section 150.

Such a recess 157 can of course also be present in the exemplary embodiment according to fig. 3.

In other respects, the embodiments according to fig. 3 and 4 are functionally similar, so that reference should also be made to the above description of the embodiment according to fig. 3.

In a further embodiment shown in fig. 5, in contrast to the embodiment according to fig. 4, a damping element 17 in the form of a wad made of viscoelastic material is arranged internally in the region of the

bent edges

155, 156. Damping between the connecting section 151 and the contact section 150 and between the connecting section 151 and the holding section 152 is provided by the damping elements 17, so that the brush holder 15 is damped viscoelastically during the elastic adjustment.

In a modification of the exemplary embodiment according to fig. 5, it is of course also possible to provide the damping element 17 only at one of the bending edges 155, 156. The damping element 17 can additionally or alternatively also be arranged at other points on the brush holder 15.

In a further embodiment shown in fig. 6, a stop element 158 is cut free from the connecting section 151, which stop element extends with a rod section 158A from the bearing section 150 in the direction of the retaining section 152, projects beyond the latter and overlaps a stop flange 158B in the form of a bent end. The stop element 158 serves to limit the adjustment travel of the retaining section 152 relative to the bearing section 150 and serves in this way in particular as an installation aid. The retaining portion 152 is therefore held in a radially outer position, viewed from the commutator 13, close to the bearing portion 150 by means of the stop element 158, which position enables the brushes 14 to be pushed axially along the axis of rotation D1 onto the commutator 13.

The cut-out 158C provided by the stop element 158, which is cut out freely from the connecting section 151, can simultaneously serve as an opening for the immersion of the brush 14, thereby increasing the possible adjustment travel of the brush 14 in the direction of the abutment section 150.

In other respects, the embodiment according to fig. 5 and 6 is functionally similar to the embodiment according to fig. 3 and 4, so that reference should be made to the above-described embodiments.

When the electric motor 1 is installed, the brush 14 comes into contact with the outer circumferential side 130 of the commutator 13 with its contact surface 140. As is schematically evident from fig. 7, the contact surface 140 is curved concavely and, in the exemplary embodiment shown, in the initial state before the electric motor 1 is put into operation, has a curvature with a radius of curvature R1 which is greater than the curvature of the outer circumferential side 130 of the commutator 13. Correspondingly, the radius of curvature R1 of the concave contact surface 140 is smaller than the radius of curvature R2 of the outer peripheral side surface 130 of the commutator 13.

This serves to obtain advantageous running-in characteristics of the electric motor 1. Therefore, during the start-up operation, the brush 14 first comes into contact with the commutator 13 only via its outer, longitudinally extending edge 143 (due to the oblique arrangement of the electric motor shaft 12 (see fig. 1), first even only the end point 143A of the edge 143 comes into contact with the commutator 13 during the start-up operation). During operation, a wear-type wear-out occurs on the brush 14, and thus, in the worn-in state, a surface-type contact is produced between the contact surface 140 and the circumferential side 130 of the commutator 13. Due to the concave curvature of the contact surface 140, already in the initial state, favorable running-in behavior is achieved when the lamellae 131 of the commutator 13 are in defined contact during the start-up operation.

The idea on which the invention is based is not limited to the embodiments described above, but may in principle also be implemented in a completely different way.

The elasticity of the brush holder and the adjustment of the stroke can be adjusted over the length of the individual segments and also over the bending angle. The segments bent over one another can thereby bring the brush into an advantageous position for contacting the commutator during reliable readjustment during operation and hold the brush there.

An electric motor of the type described here can be used advantageously for adjusting devices in vehicles, but can also be used in completely different applications. An electric motor of the type described here can be used, for example, in window lift drives for adjusting window panes in vehicles or, as a rule, in drives for adjusting covering elements in vehicles.

List of reference numerals

1 electric motor

10 stator

11 rotor

12 motor shaft

13 commutator

130 peripheral side surface

131 sheet

14 electric brush

140 contact surface

141 main body

142 plug section

143 edge

143A end point

15 electric brush holder

150 abutting section

151 connecting section

152 holding section

153 contact pin

153A end

153B bending section

153C pin section

153D opening

154 plug opening

154A splint

155. 156 curved edge

157 hollow part

158 stop element

158A rod segment

158B stop lug (bent end)

158C opening

16 Carrier plate (printed circuit board)

160 surface

161 contact opening

17 damping element

18 casing

2 drive unit

20 drive worm

22 shaft

23 output element (rope reel)

24 transfer element

3 load bearing element

Angle alpha, beta

B1 and B2 bending directions

D1, D2 rotation axis

Radius R1, R2

V adjustment direction

Claims

1. An electric motor (1) having

-a stator (10),

-a rotor (11) rotatable relative to the stator (10),

-a commutator (13) operatively connected to the rotor (11) and rotatable with the rotor (11),

-a carrier element (16) fixed in orientation with respect to the stator (10),

-a brush holder (15) arranged on the carrier element (16), and

-a brush (14) arranged on the brush holder (15), which brush is in electrical contact with the commutator (13),

it is characterized in that the preparation method is characterized in that,

the brush holder (15) is formed by a leaf spring element having an abutment section (150) which abuts against the carrier element (16), a retaining section (152) which carries the brush (14), a connecting section (151) which integrally connects the abutment section (150) and the retaining section (152) to one another and which is bent both relative to the abutment section (150) and relative to the retaining section (152),

the brush (14) bears with a contact surface (140) facing away from the retaining section (152) against an outer circumferential side (130) of the commutator (13),

the brush (14) is concavely curved on the contact surface,

the connecting section (151) has a first acute angle (a) relative to the retaining section (152) and a second acute angle (β) relative to the contact section (150),

the connecting section (151) is bent at the first bending edge (155) in a first bending direction (B1) relative to the contact section (150), and the retaining section (152) is bent at the second bending edge (156) in a second, opposite bending direction (B2) relative to the connecting section (151).

2. The electric motor (1) according to claim 1, characterized in that the contact surface (140) has a first radius of curvature (R1) and the peripheral side surface (130) has a second radius of curvature (R2), wherein the first radius of curvature (R1) is smaller than the second radius of curvature (R2).

3. Electric motor (1) according to claim 1, characterized in that said abutment section (150), said connection section (151) and said retaining section (152) are arranged zigzag with respect to each other.

4. Electric motor (1) according to claim 1, characterized in that the brush (14) is inserted into an opening (154) of the retaining section (152).

5. The electric motor (1) according to claim 1, characterized in that the abutment section (150) abuts a surface (160) of the carrier element (16) in a surface-mounted manner.

6. The electric motor (1) according to claim 1, characterized in that the brush holder (15) has at least one contact pin (153) arranged on the abutment section (150) for embedding into a contact opening (161) of the carrier element (16).

7. The electric motor (1) according to claim 6, characterized in that the contact pin (153) is constructed integrally with the abutment section (150).

8. The electric motor (1) according to claim 6, characterized in that a bent section (153B) of the contact pin (153) is bent away from the carrier element (16) starting from an end (153A) connected to the contact section (150) and thereby protrudes from the carrier element (16).

9. The electric motor (1) according to claim 8, characterized in that the contact pin (153) has a pin section (153C) coupled with the curved section (153B), which pin section extends through an opening (153D) of the abutting section (150) perpendicularly to the abutting section (150).

10. The electric motor (1) according to claim 1, characterized in that the brush holder (15) has a damping element (17) for damping a relative movement between the abutment section and the connection section (151) and/or a relative movement between the connection section (151) and the retaining section (152).

11. Electric motor (1) according to claim 1, characterized in that the brush holder (15) has a stop element (158) for limiting the movement of the retaining section (152).

12. The electric motor (1) according to claim 11, characterized in that the stop element (158) is constructed in one piece with the abutment section (150) and protrudes with a stem section (158A) from the abutment section (150).

13. Electric motor (1) according to claim 12, characterized in that the rod section (158A) has a stop lug (158B) on the end remote from the abutment section (150) for limiting the movement of the retaining section (152).