Abstract: A brush holder assembly (12) for a rotating electrical machine such as an alternator (10) has a cavity (56) therein. The cavity (56) is defined by a first wall (60), a second wall (62), a third wall (64), and a fourth wall (66). The cavity (56) is sized to receive a brush (42) of the rotating electrical machine. One of the walls (60), (62), (64), and (66) comprise a first drafted surface. A positioning rib (70) is provided on at least the drafted surface to position the brush (42) substantially parallel to the longitudinal axis (58) of the cavity (56).

Abstract: An electric drive unit for vehicle systems, such as power windows and windshield wipers, having a commutator motor that has a commutator and at least two commutator brushes. The electric drive unit includes electrical components of an electronic system for the motor. To reduce production costs and simplify assembly, the electrical components are electrically secured to a lead frame that makes the electrical connection between the components and the commutator motor and the commutator brushes are embodied as hammerhead brushes, whose carrier plates are bent in one piece out of the lead frame.

Abstract: Pseudoelastic elements are subjected to pre-strains and restrained in order to form springs which exhibit relatively constant force levels over a major fraction of maximum deflection capacity during loading and also during unloading. Pre-straining of pseudoelastic elements subjects them to strains which approach or reach the upper stress plateau of the pseudoelastic stress-strain curve. Loading of said pseudoelastic springs thus produces strains largely corresponding to the upper pseudoelastic stress plateau where strain variations cause relatively small changes in stress. Unloading of said pseudoelastic springs also produces strains largely corresponding to the lower stress plateau of the pseudoelastic stress-strain curve where stress is subject to relatively small changes with strain variations. Said psueodoelastic springs can be used in brush holders which can benefit from a relatively constant level of force as deflections occur due to brush wear.

Abstract: A small commutator motor (1), in particular a blower motor for motor vehicles, has a rotor shaft (2) rotatably mounted in at least one rotor bearing (12) in a motor housing (8, 9). A commutator (18) and an armature winding (21) electrically connected with the commutator (18) are arranged on the rotor shaft (2) so as to be fixed with respect to rotation relative to it. Further, brush guides (11) for receiving brushes (16) held in sliding contact at the commutator (18) and an end shield (10) which fixes the first rotor bearing (12) in place are provided. The end shield (10) and the brush guides (11) are formed as a one-piece structural component part which is a component part of the motor housing (8, 9) as a first motor housing part (8).

Abstract: An axially movable protective sleeve is provided for the axial assembly of a rotor-side commutator onto a stator-side brush holder. The protective sleeve both protects against moisture and provides an axial assembly that is simple in production. The axially movable protective sleeve encircles a commutator, and initially secures brushes in a retention position for assembly and then releases the brushes to rest on a brush contact surface of the commutator, when the commutator is in its operational end position.

Abstract: A DC motor includes an armature, an armature shaft, a commutator, a plurality of brushes in contact with the commutator, a plurality of brush springs for respectively biasing the brushes against the commutator, and a brush holder unit for holding the pair of brushes. Each of the brush springs comprises a springy spring body disposed at a side of corresponding one of the brushes and a spring arm extending from the spring body to bias the rear end of the corresponding one of the brushes against the commutator, and the spring body has an outer periphery disposed within the axial length of the corresponding one of the brushes.

Abstract: The present invention relates to a brush cover of a starter which is capable of stably assembling a cover to one side of a brush holder by installing a brush in a holder of a brush apparatus and connecting a cable to the brush in a brush apparatus in which a power is supplied to an armature of a starter installed for starting an engine for thereby implementing a rotation operation of the armature.

Abstract: The present invention provides a brush holder assembly structurally avoiding electrical short circuiting incidents involving positive-side leads, improving productivity and enabling costs to be reduced. Tabs for securing positive-side brush holder frames are disposed in diagonally opposite positions. The tabs disposed on the side out of which the leads pass are positioned radially outside the range of movement of the positive-side leads and the tips of the tabs are bent in directions in which the positive-side leads do not come into contact therewith. On the other hand, the tips of the tabs disposed on the opposite side from the side out of which the leads pass are bent in the opposite direction to the tips disposed on the side out of which the leads pass.

Abstract: The present invention provides a brush holder assembly enabling a common brush holder frame to be used regardless of the direction in which a lead is to pass out, improving productivity and preventing decreases in quality due to the incorrect mounting of parts, etc. A plurality of brush holder frames are secured to a base such that the openings of respective brush receiving recesses face a passage and the axes of the brush receiving recesses are directed towards the central axis of the passage. Lead outlet grooves are disposed in both sides of each of the brush holder frames so that each extends from a first end towards a second end and joins the respective brush receiving recess to the outside. Brushes are inserted into the brush receiving recesses so that leads attached to the side thereof pass through one of the lead outlet grooves in said brush holder frames and are held by each of the brush holder frames.

Abstract: Brush card or holder assemblies are disclosed. The assemblies avoid any need for a separate plastic cap and utilize a lead wire (which could be or include a rod or other electrically-conductive device) both electrically to connect a brush to an external component and mechanically to fix the position of one end of a mechanism, such as a spring, for biasing the brush toward the surface of a commutator or other rotating machine element.

Abstract: The invention concerns a brush system for a commutated DC motor. As the brush wears, different cross-sectional shapes, at different positions, come into contact with the commutator. The center of contact for each cross-sectional shape can be different, thereby changing brush angle as wear occurs. The change in brush angle can be desirable, in order to offset other effects which occur as a result of wear. For example, motor speed can change as a result of brush wear. Changing brush angle can offset the change in speed.

Abstract: The present invention relates to a replacement alternator constructed to replace an existing CS-130 alternator in a vehicle where the CS-130 alternator was disposed in a predetermined alternator space within the vehicle. The alternator space has a predetermined length, width and height. The alternator comprises a housing defining an alternator interior space. The housing is sized to fit within the predetermined alternator space. A rotor coil having a plurality of wire windings wound thereabout is disposed in the alternator interior space of the housing and rotatably supported by the housing. The wire windings of the rotor coil have an electrical current flowing therethrough for generating a rotating magnetic field as the rotor coil rotates. Means are provided for selectively rotating the rotor coil at a speed of at least 1600 revolutions per minute. The alternator includes a stator positioned in the rotating magnetic field generated by the rotor coil and supported by the housing.

Abstract: Disclosed is a flat type two-phase vibration motor. The flat type two-phase vibration motor comprises a lower board attached to an upper surface of a lower case; a stator magnet disposed on the lower board and having magnetic poles of the number of 2n where n is an integer of 1 or more; a shaft supported between the lower case and an upper case; an upper board rotatably coupled to the shaft to be eccentrically supported thereby; an armature coil of two phases attached to the upper board such that it has a phase difference of &pgr;/2; a commutator attached to the upper board around the shaft and having a plurality of segments of the number which is two times the number of the magnetic poles; and a pair of brushes having lower ends which are attached to the lower board and upper ends which are arranged such that they can be brought into contact with the segments of the commutator while being separated from each other by an electrical angle of &pgr;.

Abstract: A brush assembly preferably for a universal motor comprises a tubular brush holder 13, a carbon brush 33, an arm 31 for biasing the brush and a spring 85 for biasing the arm. The brush is slidably mounted in the cavity 21 of the holder. A stop 61 is formed between the brush and the holder and has a disengaged position to permit travel of the brush partially through the inner end 25 of the holder and an engaged position to limit travel of the brush through the inner end 25 of the holder. The electrically conductive arm 31 is pivotally mounted on the support and extends through a slot 29 of the holder. A distal end 60 of the brush engages the outer end 53 of the brush and biases the brush 33 toward the inner end 25 of the cavity. The spring 85 is connected between the support 15 and the arm 31 for biasing the arm 31 into engagement with the brush 33. The arm is spaced outwardly of the end of the slot to apply a bias to the brush when the stop is in an engaged position.

Abstract: An electrical drive unit for windshield wipers of a motor vehicle, including a drive motor which has an armature accommodated in a substantially cup-shaped housing, and a substantially cup-shaped gearbox for receiving gear elements which is secured on a face end to the housing and is closable by a gearbox cover. A closable opening is provided in the gearbox or housing, through which opening a brush holder support that holds commutator brushes can be pushed in a radial direction onto the commutator of the drive motor.

Abstract: A structure for mounting a brush on an electric motor, including a mounting bracket having an opening at one end for allowing the brush to slide out of the mounting bracket and abut a moving conductor, a slot formed in a side wall of the mounting bracket for passing a pigtail wire, a tab portion in the side wall extending across the slot near the opening of the mounting bracket, and wherein the tab portion forms a space between the side wall and the brush for accommodating the wire as the brush slides out of the mounting bracket.

Abstract: An electric motor assembly includes an electric barrier member positioned between the electric brushes and the bearing. The electric barrier member preferably is a generally annular disk made from a high-temperature dielectric material. The non-conductive barrier member ensures that no electrical communication occurs between the brushes and the bearing despite a close proximity between those components. A method of making a motor assembly to include a non-conductive barrier member designed according to this invention is also disclosed.

Abstract: In order to provide a more cost effective electric power supplying apparatus simpler in structure and operation, the apparatus 1 is constituted by attaching an electric power receiving part to an electric power supply part 2. The electric power receiving part comprises a shaft 7 provided on the end of a rotary member 3 at the rotational center thereof. The electric power supply part 2 comprises brush belts 5 each including a plurality of flexible linear conductive elements arranged so as to abut against the peripheral surface of the shaft 7.

Abstract: An electric motor with a sensor, in particular an rpm sensor, is proposed. The sensor contains at least one means (20), generating a magnetic field, as the signal emitter, at least one magnetic field sensor (28, 30) as the signal receiver, and signal conducting means (22, 24, 26). The signal conducting means (22, 24, 26) contain magnetically conducting material and conduct the signal of the at least one magnetic field-generating means (20) to the at least one magnetic field sensor (28, 30). At least one current conducting means (40, 42, 44) is arranged essentially along the signal conducting means (22, 24, 26).

Abstract: A thermal protection mechanism for electric motors is disclosed. A brush is urged into electrical contact with a commutator by a primary brush spring. A thermally deformable fastener releasably secures the primary brush spring to a brush housing. A secondary brush spring urges the brush away from the commutator with a force less than that of the primary spring. A thermal overload condition within the motor causes the thermally deformable fastener to substantially deform so that the force exerted on the brush by the primary spring is substantially reduced. The force exerted by the secondary spring overcomes the primary spring so that the brush is forcefully disengaged from electrical contact with the commutator, thereby terminating operation of the motor.

Abstract: In a brush holder device, in which an action-side end portion 22a of a torsion spring 22 is engaged with a torsion spring engaging groove 25 recessedly provided in an end surface of the brush 24 on the side opposite to a commutator 23, so that the elastic force of the torsion spring presses the brush against the commutator 23, a first inclined surface 26 is formed in the end surface of the brush 24 so as to incline at an angle of 15.degree. relative to a plane perpendicular to the axis of the brush, and second inclined surface 27 is formed in the engaging groove 25, being superposed on the first inclined surface 26. Further, a pigtail 28 is connected to the brush at an offset point relative to the engaging groove 25. Because of the second inclined surface, the torsion spring can suppress so-called "wild behavior" of the brush, and thereby, can prevent brush sound. The angle of inclination of the first inclined surface can be set at a small value, the brush can be molded using a molding die.

Abstract: A brush holder assembly for mounting on an electric machine casing. The brush holder assembly includes a brush, a brush guide that supports and guides the brush for travel, a spring for biasing the brush in a direction toward a commutator, and an electric insulator mounting for mounting the brush guide on a casing. The electric insulator mounting has electric insulator elements containing grooves engaging the side edges of the brush guide to support the brush guide and the brush in spaced relation to a casing when the brush holder assembly is mounted thereon. The brush guide has at least one wiring tab. Several forms for attaching the insulator elements to the casing are disclosed including threaded fasteners; integral grommet formations of the insulator elements; and the insulator elements being integral formations of the casing.

Abstract: A carbon brush for an electric machine, resiliently acting on a collector, is arranged within a guideway so as to be movable radially to the collector and is inflexibly connected with a bending leg. The carbon brush allows easy and cost-saving assembly in a motor and electric contacting. The bending leg serves the resilient advance of the carbon brush towards the collector, on the one hand, and the electric power supply, on the other hand.

Abstract: The invention relates to a brush holding device used in a motor, and a method of assembling a brush holding frame onto a base plate in the brush holding device. In the brush holding device, flanged portions are protruded from both sides of a lower portion of a brush holding frame, and a pair of fixing portions each having a recessed portion substantially identical in shape to a cross-sectional shape of a corresponding one of said flanged portions are provided. The brush holding frame is inserted between the fixing portions while being slid on and along a base plate surface until the flanged portion on both sides of the brush holding frame are respectively fitted to the recessed portions of the fixing portions. Cover portions are provided on the brush holding frame at a level lower than the guide hole so as to cover the fixing portions when the fixing portions and flanged portions are fitted together.

Abstract: An electric motor has brushes preassembled in casings on a brush holder plate. To keep the brushes in the casings as long as a collector of the motor has not yet been fitted, a retaining ring in front of the brushes is installed, this retaining ring being gradually replaced by the collector when the latter is fitted. The retaining ring is introduced into a specially provided space of an accommodating chamber in a bearing support, provided with a slot and thus resilient in a radial direction. Therefore, the ring may abut with preload on the outside walls of the accommodating chamber. Frictional engagement between the ring and the walls of the accommodating chamber is established, preventing rattling noise or wear as a result of movement of the retaining ring.

Abstract: An improved method for the manufacture of a compact brush guide holder assembly which is commonly found on machines in which electricity is to be transferred between an electrically conductive brush element as it moves and makes contact with a rotatable conductor such as a commutator. The brush holder assembly constructed of material that reduces antifrictional forces having a guiding channel or chamber defined by upper and lower curvilinear surface for supporting the electrically conductive brush element which receives compressed tension from a fixed non-removable constant force spring which is composed of a beam uncoiled section in addition to a coiled section having integrally fixed mounted Teflon bushings that are free to ride and float horizontally and vertically on mounting post that pass through its center.

Abstract: A commutator system comprising a commutator and a commutator brush. The commutator has electrically conducting surfaces that are electrically separated from each other by non-conducting segments. The edges of the conducting surfaces adjacent to the non-conducting segments are oriented at an angle to the rotational axis of commutator. The commutator brush has edges oriented at substantially the same angle.

Abstract: The present invention offers a commutation assembly for an electrical motor, whereby a constant optimal pressure is maintained upon the commutator of the motor.

Abstract: In a starter for an internal combustion engine, comprising: a pinion; shift mechanism for moving the pinion into mesh with a ring gear of the engine; a housing for accommodating the pinion and the shift mechanism; an electric motor for rotating the pinion; a substantially cylindrical motor casing for accommodating the electric motor; a contact unit for selectively providing electric power to the electric motor; a brush holder stay disposed between the housing and the motor casing, the brush holder stay having a cavity opened toward the motor casing and the contact unit being mounted in the cavity; and a cover for covering the cavity of the brush holder stay, the cover is made of a flexible member so that the cover is naturally curved, and the cover is disposed between the brush holder stay and the motor casing with its concave surface facing the brush holder stay so that the cover is pushed toward the brush holder stay by an axial end of the motor casing.

Abstract: In an ordinary DC motor in a windshield wiper, operating speed tends to increase as the motor brushes become seated. The invention counteracts this tendency by providing a brush geometry which causes the effective angular position of a brush to change during seating. The change is in a direction which tends to reduce speed.

Abstract: A resilient thin sheet is used for a brush instead of a conventional brush unit which includes coil springs, pig tails and graphite brushes. A slip ring is made of perforated copper which is impregnated with carbon powder. The brush has two arc-shaped arms extending along the circumference of the slip ring and contacting portions disposed at the edges of the arms which are in contact with the peripheral surfaces of the slip ring. Wear resistant members are welded or caulked to the contacting portions to prevent excessive wear of the brush, thereby increasing the life of the brush.

Abstract: Power supply is accomplished via two rails, which are arranged in one plane and which in each case have lugs, which can be bent out from the rail plane. In this case, contact arm of at least one lug is run away over a rail. In this way, a system which is quick to install and which, moveover, is quickly extended in the axial direction is produced.

Abstract: A series motor armature support assembly comprises a bearing receiving member (60), a pair of legs (62, 64) extending from the bearing receiving member (60), and a brush holding assembly receiving member (66, 68) coupled with each leg. The brush holding assembly receiving member (66, 68) includes a ledge (110, 110') coupled with a leg (62, 64), a stop (114, 114') coupled with the ledge (110, 110'), and a support (122, 122') extending from the bearing receiving member (60) towards the ledge (110, 110'). A securing member (70, 72) is coupled with the legs and secures the support to a stator (34), which is secured to a base (32). A brush holding assembly (80) is received in the brush holding member (66, 68). The brush holding assembly (80) includes a brush receiving member (160), a terminal connector (162) coupled with the brush receiving member (160), and a biasing retention member (164) coupled with the brush receiving member (160).

Abstract: A miniature electric motor having a wound rotor uses brush gear 20 comprising strips 23 formed from flexible printed circuit board material 22 having a conductive layer 24 and a supporting layer 25. The conductive layer 24 is electrically connected to motor terminals 19 and to a contact portion 26 arranged for making sliding contact with a commutator of the motor. The contact portion 26 of the brush 21 may be coated with a precious metal for contact or corrosion resistance requirements. The backing material 25, preferably polyimide, is chosen of a desired thickness to provide strength, resilience and vibration damping characteristics while remaining flexible.

Abstract: This invention relates to a carbon brush for an electric motor. These carbon brushes are guided in tubular brush holders and are pressed against a commutator. Furthermore, the brushes of the present invention include inclined side edges so that the front frontal surface has a trapezoidal cross-section. The consequence thereof is that, when sliding along the commutator, the commutator bars will always support the side edges over the major part of their length. The ratchet effect is thus suppressed.

Abstract: A brush holder assembly comprises a non-conductive brush holder body covered by a printed wiring board cover. The brush holder body includes a brush cavity for holding a brush, a spring cavity for holding a spring and a shunt wire cavity for holding a shunt wire. The spring is configured to hold the brush in contact with a commutator at a constant brush pressure throughout the entire length of brush travel. The brush holder body and printed wiring board cover are configured to enclose the brush, spring and shunt wire thus protecting the brush, spring and shunt wire.

Abstract: The invention provides a brush cartridge for a commutator-type motor. The brush cartridge includes a housing that is made of an electrically conductive material and that has an integrally formed terminal so that the cartridge can be plugged into a circuit without the need for wiring. The brush cartridge also includes a brush supported in the housing for sliding movement relative thereto and a spring member for biasing the brush into engagement with a commutator on the motor when the cartridge is installed. The brush cartridge also includes a flexible shunt connected between the housing and the brush. The shunt limits the range of sliding movement of the brush to permanently retain the brush in the housing.

Abstract: A brush holder embodies certain generic features that render it suitable for use in numerous brush card assemblies. The brush holder has sidewalls that provide guidance of an associated brush, and integral locators for locating an associated spring strip for urging the brush toward a commutator. A brush holder may be formed singly, or multiple brush holders may be integrally formed and joined by an integral bus bar.

Abstract: An improved brush assembly is provided for conducting electrical power from a fixed power system to a rotating ice protection system. The invention is especially adapted for use with an aircraft propeller ice protection system. According to an aspect of the invention, the brush assembly has a housing with a brush enclosure, the enclosure having slots provided therein for slidably receiving a plurality of brushes. A plurality of wear inserts are disposed in the slots adjacent the brushes in order to provide a wearing surface to prevent excessive wear of the brushes.

Abstract: A substantially enclosed brush holder assembly includes a brush fixture of singular piece construction for use in a harsh operating environment, such as that in which a motor vehicle alternator operates. An exemplary brush holder assembly according to the present invention includes a brush fixture for use in connection with a dynamoelectric machine. The brush fixture has at least one brush compartment that is configured to receive a brush. The brush fixture also includes at least one set of spring coil compartments, each of which are designed to receive one of two spring coils of a constant force extension spring. These spring coil compartments are adjacent to and in open communication with the brush compartment, thereby allowing the constant force extension spring to be extended through the brush compartment and peripherally around the brush located therein.

Abstract: In order to ensure a secure fit and a constant setting angle for a brush (4) plugged into a box-shaped brush receptacle (1) of a brush holder even in the event of relatively severe thermal and/or bending stress, a thin-walled connecting web (3) connecting a pivoted bearing arrangement (2) to the brush receptacle (1) is furcated at least at the receptacle end of the web (3). The resulting forks (3.1; 3.2) lead into the longitudinal sidewalls (1.1; 1.2) of the box-shaped brush receptacle (1), which are parallel to the connecting web (3).

Abstract: To inform a user of wear on a carbon brush for a motor earlier than when the carbon brush is actually required to be replaced with a new brush. In a motor brush wear indicating device, a metal terminal is attached to a brush holder, being opposed to the inside of a holder shank of the brush holder, and an indicator is operated when the metal terminal contacts a brush spring. The metal terminal has a contact in the middle of a length of the brush holder. The indicator can be operated while the carbon brush is continuously pressed against a commutator by the brush spring. The metal terminal serves as a leaf spring. When the carbon brush is worn and shortened, the indicator is operated. Even after the indicator operates, the carbon brush is still pressed against the commutator by the brush spring. Therefore, the user can operate a motor-driven tool for some time before the carbon brush must be replaced with a new one.

Abstract: Brush holder for a DC motor is disclosed as having at least one brush box for housing a brush biased radially toward an opening through the brush holder. A brush retainer is provided for preventing the brush from entering the opening of the brush holder until the rotor of the DC motor is assembled to the stator, where the brush retainer is releasably attached to an annular wall defining the brush holder opening. The brush holder also includes means for capturing the brush retainer once it is displaced axially during assembly of the rotor to the stator, as well as means for retaining a printed circuit board in position between the brush holder and the stator end cap.

Abstract: A commutator having a sliding surface formed by arranging a plurality of segments insulated with each other into a circle on a plane which is substantially perpendicular to a shaft is provided at one end of a armature. A plurality of brushes slide on the sliding surface. As seen from an axial direction, the brushes have a substantially trapezoidal shapes having widths that get narrower towards a center of the commutator. The brushes have a back end surface to which a spring is attached to. The back end surface is inclined towards the edge of the sliding surface of the commutator. The brush holders for receiving the brushes have recesses that are substantially trapezoidal in shape to correspond with the peripheries of the brushes.

Abstract: Around the outer circumference of an armature core 520, there are arranged a stator core 558 and a stator coil 559 wound on the stator core 558, forming a fixed magnetic field device. The stator coil 559 has its one end portion arranged in the space at the outer circumference of a planetary gear speed reduction mechanism 300, i.e., at the outer circumference of a center bracket 360. A motor partition 800 is formed with a stepped portion 810 so as to accommodate the aforementioned one end portion. On the other hand, the other end of the stator coil 559 is arranged in the space at the outer circumference of a brush 910. In short, the planetary gear speed reduction mechanism 300 has its external diameter made smaller than the inner circumferential diameter of the stator coil 559.

Abstract: A brush system for providing an electric connection to a rotating commutator wheel of an electric machine is disclosed. The brush system has a switched brush selectively switchable between an engaged position and a disengaged position and a switch connected to the switched brush and formed of a shape-memory-alloy. The switch attains an extended state at a first temperature and attaining a retracted state at a second temperature, for switching the switched brush alternately to the respective engaged position and the respective disengaged position. The switch includes a temperature conditioner for varying a temperature at the switch between the first temperature and the second temperature. The temperature condition may be an electric network wherein the internal resistance of the switch allows for heating of the switch to the second temperature.

Abstract: A brush wear sensor for a dynamoelectric machine having a rotating commutator and brushes which contact the commutator detects movement of the brush a predetermined distance inwardly which indicates excessive wear of the brush. The brush wear sensor is normally electrically isolated from the brush and from the brush holder in which the brush is mounted. When excessive brush wear occurs, the brush wear sensor contacts the spring which moves the brush as it wears and urges the brush into contact with the commutator. The brush wear sensor is then electrically connected to the brush holder and the brush, providing an indication that the brush has moved the predetermined distance inwardly. The brush wear sensor allows the detection of excessive brush wear without disassembling and visually inspecting the brushes.

Abstract: The support (6) comprises a moving brush (7) and means (10) for returning the brush so as to keep it in contact with the commutator (4) of the machine. The support (6) comprises clip-in means (13) for fastening the support to the housing (1) of the machine by clipping-in substantially radially to the axis (8) of the housing, and for separating it from this housing by substantially radial unclipping. The support can be easily removed and refitted for replacing the brush or cleaning the commutator.

Abstract: Deformation absorbing grooves 16a are recessedly provided on the inner surfaces of both side walls 15a of a main body 15 of a brush holder made of resin in the sliding direction of a brush 44, and brush holding surface portions 16b holding both end edge portions of the outer surfaces of the brush are formed at edge portions of the grooves 16a on the inner surfaces of the side walls 15a. A pair of first reinforcing ribs 16c are projectingly provided at closing end sides of cutaway portions 18 and 19 on the outer surfaces of the both side walls 15a in the sliding direction of the brush, a pair of second reinforcing ribs 16d are projectingly provided at both top sides of the outer surface of a top side wall 15d for closing an end surface across the tops of the both side walls in the sliding direction of the brush, and an end portion 46a on the reaction side of a torsion spring 46 is engaged with an engageable portion 21A projectingly provided on the first reinforcing rib 16c.

Abstract: An electric motor is provided with especially brushes of which rear ends are cut diagonally to form acute angles at the corner edges on the backward side of the rotating direction of the armature. The brushes are maintained securely in brush holders without vibration by first and second side walls of the brush holders according to component force of pressing force applied on the slant rear ends of the brushes by pressing members, therefore the objectionable noise caused by the "stick-slip" is prevented very effectively without introducing complicated structure in the motor.