JP2008099524A - Electric motor with reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electromagnetic noise generated by an electric motor with a reduction gear. <P>SOLUTION: In a wiper motor 11 having a motor body 12 and a reduction gear, an accommodating case integrally provided with a brush holder mounted on the motor body 12 is arranged on the outer side surface of the gear case of the reduction gear. A pair of choke coils and a two-way varistor are provided in a feeding circuit for connecting brushes 26a, 26b with a feeding terminal, thereby accommodating them in the accommodating case. A commutator 24 in sliding contact with the brushes 26a, 26b is fixed to an armature shaft at a lead angle in a rotational direction against an armature core 18 to which a plurality of armature coils 22 are attached by lap winding to correct the distortion of the combined magnetic field of a magnetic field formed by magnets 23a, 23b and a magnetic field generated by the armature coils 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor with a speed reduction mechanism including a motor main body provided with an armature shaft and a speed reduction mechanism that decelerates rotation of the armature shaft and outputs it from an output shaft.

  As a drive source for a wiper device, a power window device, a sunroof device or the like provided in a vehicle, an electric motor that is operated by a power source such as a battery mounted on the vehicle is usually used. In order to adapt the electric motor to these devices, it is necessary to reduce the rotation of the motor to a required number of rotations. Therefore, such an electric motor has a speed reduction mechanism attached to the motor body, and is made into one unit as an electric motor with a speed reduction mechanism.

As an electric motor with a speed reduction mechanism, for example, as shown in Patent Document 1, many motors with a brush are used as a motor body. The brushed motor has an armature shaft that is rotatably supported by the motor yoke. An armature core having a plurality of slots arranged in the circumferential direction is fixed to the armature shaft, and each slot of the armature core has a plurality of armatures. Amateur coils are installed by lap winding. Further, a commutator having a plurality of segment pieces is fixed to the amateur shaft, and the coil ends of the respective amateur coils are connected to the corresponding segment pieces. Further, a resin brush holder is fixed inside the motor yoke, and a pair of brushes slidably contacting the outer peripheral surface of each segment piece of the commutator is held in the brush holder. When power is supplied to the brush from the power supply terminal connected to the power source via the power supply circuit, power is supplied to each armature coil via the brush and the commutator, and the armature shaft rotates. .
JP 2006-94693 A

  However, in an electric motor with a reduction mechanism using a brush motor as the motor body, a surge voltage is generated by self-induction when the energized brush straddles adjacent segment pieces of the commutator. Since electromagnetic noise is radiated from the sliding contact portion with the commutator, when this electric motor with a speed reduction mechanism is mounted on a vehicle, there is a risk that other electric components and the like may be damaged by the electromagnetic noise (radio noise, etc.).

  An object of the present invention is to reduce electromagnetic noise generated by the electric motor with a speed reduction mechanism.

  An electric motor with a speed reduction mechanism according to the present invention is an electric motor with a speed reduction mechanism including a motor main body having an armature shaft and a speed reduction mechanism for decelerating the rotation of the armature shaft and outputting it from an output shaft. A motor yoke that rotatably supports the shaft, a gear case that is fixed to the opening of the motor yoke, accommodates the speed reduction mechanism, and a pair of members that are fixed to the inner surface of the motor yoke and that forms a magnetic field in the motor yoke. A magnet, a plurality of slots arranged in a circumferential direction, an armature core fixed to the armature shaft and disposed inside the motor yoke, and a plurality of segment pieces arranged at a predetermined interval in the circumferential direction; A commutator fixed to the armature shaft at a predetermined angle in the rotational direction with respect to the armature core, and wound around the slot A plurality of armature coils respectively connected to the corresponding segment pieces, a pair of brushes held in a brush holder disposed inside the motor yoke and slidably in contact with the outer peripheral surface of the commutator, and a power supply connected to a power source It is provided in the electric power feeding circuit connected between a terminal and the said brush, It has a noise prevention element which absorbs the noise which arises in the said electric power feeding circuit, It is characterized by the above-mentioned.

  The electric motor with a speed reduction mechanism according to the present invention includes a connector portion provided with a pair of the power supply terminals and disposed on the gear case, and provided integrally with the brush holder and protruding from the opening of the motor yoke toward the gear case side. A housing case disposed on the gear case, wherein the noise prevention element is housed in the housing case.

  The electric motor with a speed reduction mechanism according to the present invention is characterized in that the commutator has an advance angle of 7 degrees to 11 degrees with respect to the armature core and is fixed to the armature shaft.

  The electric motor with a speed reduction mechanism of the present invention is characterized in that the rotation direction of the armature shaft is determined in one direction.

  An electric motor with a speed reduction mechanism according to the present invention is provided on a motor yoke formed in a cylindrical shape with a bottom by a magnetic material, a pair of magnets arranged to face the inner surface of the motor yoke, and a bottom portion of the motor yoke. An amateur shaft rotatably supported by a bearing, an armature core fixed to the armature shaft, and an armature coil wound around the armature core, and an armature fixed to the armature shaft and electrically connected to the armature coil Connected commutator, a pair of brushes slidably contacting the commutator and supplying current to the commutator, and a brush disposed in the motor yoke, fixed to the motor yoke and holding the pair of brushes A holder, a worm provided on the armature shaft, and a worm meshing with the worm A gear mechanism that is fixed to the opening of the motor yoke and accommodates the speed reduction mechanism, a noise prevention circuit that is electrically connected to the pair of brushes, and an opening of the motor yoke And a housing case that is integrally coupled to the brush holder and disposed on the outer wall of the gear case, and that accommodates the noise prevention circuit, and is formed of an elastic metal, and is connected to the noise prevention circuit within the accommodation case. In an electric motor with a speed reduction mechanism including a pair of connected plates, the magnetic field generated by the armature coil is deviated from 7 to 11 degrees in the rotational direction with respect to the direction perpendicular to the magnetic field generated by the pair of magnets. The commutator is fixed to the armature shaft while being shifted in the rotational direction with respect to the armature core.

  According to the present invention, since the noise preventing element is provided in the power feeding circuit connected between the power feeding terminal and the brush, and the commutator is fixed to the amateur shaft by shifting by a predetermined angle in the rotation direction with respect to the amateur core. In addition to absorbing noise on the power feeding circuit by the noise prevention element, the distortion of the combined magnetic field formed in the motor yoke by the magnetic field generated by the magnet and the magnetic field generated by the armature coil is suppressed. The generated electromagnetic noise can be reduced.

  According to the present invention, the noise prevention element is accommodated in the accommodation case that is provided integrally with the brush holder and disposed on the gear case. Before propagating to the wiring, noise can be removed together by the noise prevention element, and thereby electromagnetic noise generated by the electric motor with a speed reduction mechanism can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a perspective view showing a wiper motor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the wiper motor shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

  A wiper motor 11 shown in FIG. 1 is used as a drive source of a rear wiper device provided in a vehicle, and is an electric motor with a speed reduction mechanism in which a motor main body 12 and a speed reducer 13 are formed as one unit.

  The motor main body 12 has a motor yoke (yoke) 14 formed of a magnetic material in a bottomed cylindrical shape with a cross-sectional shape, and an armature 15 is accommodated in the motor yoke 14. Yes. The amateur 15 includes an armature shaft 16, and one end of the armature shaft 16 is rotatably supported by the motor yoke 14 via a bearing 17 provided on the bottom of the motor yoke 14. 14 is rotatable inside.

  As shown in FIG. 2, an armature core 18 is fixed to the armature shaft 16 so as to be located inside the motor yoke 14, and ten slots 21 arranged in the circumferential direction are provided on the armature core 18. . These slots 21 are odd-shaped slots having different cross-sectional shapes, and each slot 21 is a so-called skew (oblique groove) that is inclined in the rotational direction with respect to the axial direction of the armature shaft 16.

  Each slot 21 is wound with a conducting wire between the corresponding slots 21, whereby 10 amateur coils 22 are mounted on the armature core 18 by overlapping winding. At this time, since the slot 21 of the amateur core 18 is formed in an irregular shape, the work of winding the conductive wire around each slot 21 is facilitated. Further, since the slot 21 is skewed and the armature coil 22 is mounted on the slot 21 by overlapping winding, uneven rotation of the armature 15 can be reduced.

  In the present embodiment, the armature coil 22 is mounted on the armature core 18 by lap winding. However, the present invention is not limited to this. For example, the armature coil 18 is wound around the armature core 18 by other winding methods such as wave winding. It may be.

  A pair of segment-shaped (fan-shaped) magnets 23a and 23b are fixed to the inner surface of the motor yoke 14 so that different magnetic poles face each other. Has a magnetic field. The amateur core 18 and the armature coil 22 attached to the amateur core 18 are disposed between the pair of magnets 23a and 23b, and are positioned inside the magnetic field formed by these magnets 23a and 23b.

  A commutator (commutator) 24 is fixed to the amateur shaft 16 along with the amateur core 18. This commutator 24 is formed in a cylindrical shape by an insulating material such as a resin and is fixed to the outer periphery of the cylindrical body 24a that is fitted and fixed to the armature shaft 16 with a predetermined interval in the circumferential direction. The segment end 24b of each armature 22 is electrically connected to the riser 24c of each segment piece 24b. Further, a brush holder 25 is provided inside the motor yoke 14, and as shown in FIG. 3, a pair of brushes 26a and 26b for supplying a drive current to each armature coil 22 via the commutator 24 is provided in the brush holder. 25.

  4 is a perspective view showing the details of the brush holder shown in FIG. 3. The brush holder 25 is made of a resin material, and is formed on the main body wall 25a perpendicular to the axial direction of the armature shaft 16 and the inner surface of the motor yoke 14. And an outer peripheral wall portion 25b that covers the outer periphery of the main body wall portion 25a. The outer peripheral wall portion 25b is mounted inside the motor yoke 14 so as to be in sliding contact with the inner surface of the motor yoke 14. 14 is fixed. A through hole 25c is formed in the axial center of the main body wall 25a, and the commutator 24 fixed to the armature shaft 16 is inserted through the through hole 25c and disposed inside the main body wall 25a.

  The pair of brushes 26a and 26b held by the brush holder 25 is fixed to one end of each of the leaf springs 27a and 27b which are bent in a “shape”, and the other end of each of the leaf springs 27a and 27b is a fastening member ( Bolts) 28a and 28b are fixed to the brush holder 25. As a result, the brushes 26a and 26b are slidably contacted with the outer peripheral surface of the commutator 24 in a state of being biased by the leaf springs 27a and 27b. When a drive current is supplied between the brushes 26a and 26b, this current is rectified by the commutator 24 and supplied to each armature coil 22, and an electromagnetic force is generated in the armature core 18 inside the magnetic field to generate the armature 15, The amateur shaft 16 rotates.

  On the other hand, the speed reducer 13 has a gear case 31 formed of a conductor such as an aluminum alloy, and the gear case 31 is fixed to an opening of the motor yoke 14 by a fastening member (bolt) 32 and the motor housing together with the motor yoke 14. Is configured. The gear case 31 accommodates a speed reduction mechanism (worm gear mechanism) 35 including a worm 33 and a worm wheel 34 that meshes with the worm 33, and the worm 33 is an outer peripheral surface that projects into the gear case 31 of the armature shaft 16. The worm wheel 34 is rotatably accommodated in the gear case 31. A power conversion mechanism 36 is accommodated in the gear case 31, and the rotation of the worm wheel 34 is converted into a swing motion by the power conversion mechanism 36 and output from the output shaft 37. The power conversion mechanism 36 includes a first arm member 36a and a second arm member 36b, and one end of the first arm member 36a is rotatable to a position away from the rotation center axis of the worm wheel 34 by a connecting pin 38a. The other end of the second arm member 36b is pivotally connected to one end of the second arm member 36b by a connecting pin 38b. The other end of the second arm member 36b is fixed to the output shaft 37. With such a structure, when the motor body 12 is actuated and the armature shaft 16 is rotated, the rotation is decelerated to a predetermined rotational speed by the speed reduction mechanism 35 and transmitted to the worm wheel 34, and the rotation of the worm wheel 34 is the first rotation. The first arm member 36 a and the second arm member 36 b are converted into a swinging motion and output from the output shaft 37. That is, in the wiper motor 11, the rotational motion of the armature shaft 16 that is the power of the motor body 12 is decelerated by the speed reduction mechanism 35, converted into a swing motion by the power conversion mechanism 36, and output from the output shaft 37. Yes.

  As shown in FIG. 1, a boss portion 31a is formed in the gear case 31, and an output shaft 37 is rotatably supported by the boss portion 31a and protrudes to the outside from the boss portion 31a. A rear wiper arm (not shown) is attached. Thus, when the motor main body 12 is operated, the rear wiper arm swings together with the output shaft 37, and the wiping operation by the rear wiper device is performed.

  5 is a power supply circuit diagram of the wiper motor shown in FIG. 1, and FIG. 6 is an exploded perspective view of the wiper motor shown in FIG.

  The wiper motor 11 is provided with a connector portion 42 for connecting the wiper motor 11 to a power source 41. As shown in FIG. 1, the connector portion 42 is formed as an independent unit, is disposed on the outer surface of the gear case 31, and is fixed to the gear case 31 by fastening members (bolts) 43. As shown in FIGS. 2 and 5, the connector portion 42 is provided with a pair of power supply terminals 44a and 44b, and one power supply terminal 44a is connected to the power supply 41 and the wiper switch 45 through wiring. The other power supply terminal 44b is grounded to the vehicle body via wiring. Further, in order to connect the power supply terminals 44a and 44b to the brushes 26a and 26b, a power supply circuit 46 is provided between the brushes 26a and 26b and the power supply terminals 44a and 44b as shown in FIG. Yes. When the wiper switch 45 is turned on, the drive current from the power supply 41 is supplied to the brush 26a via the power supply terminal 44a and the power supply circuit 46, and this current is rectified by the commutator 24 and supplied to each amateur coil 22. The leaf springs 27a and 27b are formed of a conductive metal plate such as a copper plate, for example. The current from the power supply terminal 44a is supplied to the brush 26a via the leaf spring 27a, and the current from the brush 26b is the leaf spring. The power is transmitted to the power supply terminal 44b through 27b.

  The motor body 12 used in the wiper motor 11 is a rotation direction designation type motor in which the rotation direction of the armature shaft 16 is set to one direction, that is, the armature shaft 16 rotates only in one direction. Only the on / off of the motor body 12 is switched by the operation of the switch 45, and the armature shaft 16 always rotates in the same direction during operation.

  The connector portion 42 is provided with a switch terminal 47 for an automatic stop circuit. The switch terminal 47 is inserted into the gear case 31 through an insertion hole (not shown) provided in the gear case 31 and rotates together with the worm wheel 34. It is in contact with a relay plate (not shown). When the rear wiper arm is in the lower inverted position, a position detection signal is output from the position detection terminal 48 of the connector portion 42 to the control device (not shown) via the switch terminal 47 and the relay plate. And even if the wiper switch 45 is randomly stopped, the control device stops the motor main body 12 when the rear wiper arm is in the lower reverse position.

  In order to absorb noise such as a surge voltage generated on the power supply circuit 46 by sliding contact between the brushes 26a and 26b and the commutator 24 and reduce electromagnetic noise radiated from the wiper motor 11, a noise prevention element is provided in the power supply circuit 46. A pair of choke coils 51a and 51b is provided. One choke coil 51a is connected in series between the power supply terminal 44a and the brush 26a, and the other choke coil 51b is connected in series between the power supply terminal 44b and the brush 26b, and each power supply terminal 44a. 44b, a bidirectional varistor 52 as a capacitive element having a function of a capacitor and a varistor is connected in parallel with each choke coil 51a, 51b. That is, the power supply circuit 46 is provided with a noise prevention circuit including a pair of choke coils 51a and 51b and a bidirectional varistor 52, and the brushes 26a and 26b are electrically connected to the noise prevention circuit. .

  As shown in FIGS. 1 and 6, a housing case 53 is disposed on the outer wall of the gear case 31, that is, on the outer surface. Is housed inside. The housing case 53 is formed of a resin material in a vertically long bathtub shape, and is fixed to the brush holder 25 at one end thereof along the outer peripheral wall portion 25b as shown in FIG. In other words, the storage case 53 is coupled or fixed to the brush holder 25 and is provided integrally with the brush holder 25. When the brush holder 25 is attached to the motor yoke 14, the storage case 53 is removed from the inside of the motor yoke 14. It protrudes toward the gear case 31 through the opening. When the motor yoke 14 is fixed to the gear case 31, the housing case 53 is arranged on the outer wall of the gear case 31.

  As a result, even if noise is generated from the sliding contact portion between the brushes 26a, 26b and the commutator 24, the choke coils 51a, 51b and the bidirectional varistor 52 absorb the noise flowing in the power feeding circuit 46 and to the outside of the motor. The radiation of electromagnetic noise can be reduced. Further, the choke coils 51a and 51b and the bidirectional varistor 52 are disposed outside the motor yoke 14 and immediately after the outlet of the power supply circuit 46 from the motor yoke 14, that is, immediately after the opening of the motor yoke 14. The electromagnetic noise radiated to the outside from the inside of 14 through the opening can be removed before propagating to other wirings or the like.

  As described above, in the wiper motor 11, the choke coils 51a and 51b and the bidirectional varistor 52 are arranged outside the motor yoke 14, so that electromagnetic noise coming out from the inside of the motor yoke 14 through the opening. Can be removed together before propagating to other wiring, and electromagnetic noise radiated from the wiper motor 11 can be reduced.

  The storage case 53 is provided with a partition wall 54 that divides the interior of the storage case 53 into three spaces. The choke coils 51a and 51b are arranged in parallel with each other and separated from each other by the partition wall 54. 53. The bidirectional varistor 52 is arranged side by side on the connector portion 42 side with respect to the choke coils 51a and 51b, and is housed in the housing case 53 in a state of being separated from the choke coils 51a and 51b by a partition wall 54. The spaces defined by the partition walls 54 are set to shapes and sizes corresponding to the outer shapes of the choke coils 51a and 51b and the bidirectional varistor 52. The choke coils 51a and 51b and the bidirectional varistor 52 are provided in each space. Can be easily installed.

  Reference numerals 55a and 55b are connection plates formed of elastic metal and connected to one end of the choke coils 51a and 51b inside the housing case 53 and connected to the power supply terminals 44a and 44b, respectively. Each of the connecting plates is made of an elastic metal and is connected to the other ends of the choke coils 51a and 51b in the housing case 53 and to the brushes 26a and 26b. In FIG. 6, the storage case 53 is in a state where the lid is removed. Further, the connection plate 55b is grounded to the gear case 31 by the ground wire 57a, the connection plate 56b is grounded to the motor yoke 14 by the ground wire 57b, and the motor yoke 14 and the gear case 31 are electrically connected. The motor yoke 14 and the gear case 31 have a shielding effect against noise.

  FIG. 7 is an explanatory view showing the fixed positions of the amateur core and the commutator to the amateur shaft, and FIG. 8 is a wiring diagram of an amateur coil mounted on the amateur core. In the present embodiment, since the slots 21 provided in the amateur core 18 are skewed, the rotational position of each slot 21 with respect to the commutator 24 is set based on the intermediate position of the armature core 18 in the axial direction. ing.

  In the wiper motor 11, choke coils 51 a and 51 b and a bidirectional varistor 52 are provided in the power supply circuit 46 to reduce the generation of electromagnetic noise, and an advance angle is set in the armature 15. The electromagnetic noise radiated from the wiper motor 11 is further reduced.

  As shown in FIG. 7, each brush 26a, 26b held by the brush holder 25 has a magnetic field generated by the direction of the straight line L1 connecting the midpoints in the circumferential direction of the pair of magnets 23a, 23b, that is, the pair of magnets 23a, 23b. The armature shaft 16 is disposed so as to be shifted by 35 degrees in the rotational direction of the armature 16 with respect to the direction. On the other hand, the commutator 24 is further shifted by 9 degrees in the rotational direction with respect to the armature core 18 in addition to the shift amount of the brushes 26a and 26b with respect to the straight line L1 (35 degrees in the present embodiment), that is, the advance of 9 degrees. It is fixed to the amateur shaft 16 with a corner. In other words, when the advance angle is not set, the commutator 24 is fixed to the armature shaft 16 with respect to the armature core 18 by being shifted in the rotational direction by the amount of shift of the brushes 26a and 26b with respect to the straight line L1 connecting the midpoints of the magnets 23a and 23b. However, in this wiper motor 11, in addition to the deviation of the brushes 26a and 26b with respect to the straight line L1, the commutator 24 is fixed to the armature shaft 16 with an advance angle of 9 degrees relative to the armature core 18 in the rotational direction. I am doing so. Thereby, in the case of the present embodiment, the commutator 24 is fixed to the armature shaft 16 with a shift of 44 degrees in the rotation direction with respect to the armature core 18 as compared with the case where the advance angle is not set.

  On the other hand, the end of each armature coil 22 attached to the armature core 18 is connected to the adjacent segment piece 24b, and is wound around a predetermined pair of slots 21 across the three slots 21. As described above, the commutator 24 has an advance angle of 9 degrees in the rotational direction with respect to the armature core 18 and is fixed to the armature shaft 16, so that each energized armature is shown in FIG. The neutral axis L2 of the magnetic field generated by the coil 22 is shifted by 9 degrees in the rotational direction with respect to the midpoint in the circumferential direction of the pair of magnets 23a and 23b, that is, the straight line L1. That is, in the wiper motor 11, the position of the brushes 26a and 26b is not shifted in the rotational direction with respect to the direction of the straight line L1 connecting the circumferential midpoints of the pair of magnets 23a and 23b, but an advance angle is provided. The advance angle is set by shifting the commutator 24 slidably in contact with the brushes 26a and 26b to the amateur shaft 18 to which the armature 22 is attached and shifting the commutator 24 to the armature shaft 16 in the rotational direction.

  In FIG. 8, only three armature coils 22 are shown, but the other seven armature coils 22 are also mounted in corresponding slots 21 by overlapping winding in the same pattern.

  With such a configuration, when a driving current is supplied to the armature coil 22 via the brushes 26a and 26b, the armature coil 22 energized in a direction perpendicular to the magnetic field generated by the pair of magnets 23a and 23b is generated. The magnetic field is shifted by 9 degrees in the rotation direction. As a result, the combined magnetic field of the magnetic field formed by the magnets 23a and 23b in the motor yoke 14 and the magnetic field generated by the armature coil 22 has a neutral axis distortion caused by the advance angle. The combined magnetic field is corrected so as to be parallel to the straight line L1 connecting the midpoints in the circumferential direction of the magnets 23a and 23b. That is, when the advance angle is not set, the neutral axis L2 of the magnetic field generated by the armature coil 22 coincides with the direction of the magnetic field generated by the magnets 23a and 23b (direction in the straight line L1), and therefore the magnetic field generated by the magnets 23a and 23b The combined magnetic field generated by the amateur coil 22 is a curved magnetic field in which the neutral axis is shifted to the opposite side of the rotation direction. In the wiper motor 11, the commutator 24 is advanced with respect to the amateur core 18, and the amateur shaft 16 By fixing to, the neutral axis of the combined magnetic field can be shifted in the rotational direction to reduce the distortion of the combined magnetic field. Therefore, the rectification of the current supplied to each armature coil 22 through the commutator 24 and the brushes 26a and 26b is optimized, thereby reducing electromagnetic noise generated from the sliding contact portion between the brushes 26a and 26b and the commutator 24. Is done.

  Thus, in the wiper motor 11, the power feeding circuit 46 is provided with the choke coils 51 a and 51 b and the bidirectional varistor 52, and the commutator 24 is fixed to the armature shaft 16 with an advance angle with respect to the armature core 18. As a result, the rectification of the current supplied to the armature coil 22 can be optimized due to the effect of the advance angle, thereby greatly reducing electromagnetic noise generated from the sliding contact portion between the brushes 26a and 26b and the commutator 24. Can do.

  Further, since the advance angle is set by shifting the commutator 24 with respect to the armature core 18 and fixing it to the armature shaft 16, the brushes 26a and 26b are used when the oval motor yoke 14 is used. Even when the layout of the brush holder 25 is limited, the advance angle can be set regardless of the arrangement positions of the brushes 26a and 26b.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the present embodiment, the case where the present invention is applied to the wiper motor 11 that drives the rear wiper arm of the vehicle is shown. However, the present invention is not limited to this. For example, driving of a power window device, a sunroof device, etc. The present invention may be applied to a motor or the like used as a source.

  Further, in the present embodiment, the advance angle of 9 degrees is given to the armature core 18 and the commutator 24 is fixed to the armature shaft 16. However, the present invention is not limited to this, and the advance angle range is the motor body. It can be arbitrarily set in accordance with the specification of 12, and it is particularly preferable to advance the angle in the range of 7 to 11 degrees.

  Furthermore, in the present embodiment, ten slots of the armature core 18 and ten segment pieces 24b of the commutator 24 are provided, but the present invention is not limited to this, and can be arbitrarily set according to the specifications of the motor body 12. it can.

  Furthermore, in the present embodiment, the speed reducer 13 is provided with the power conversion mechanism 36. However, the present invention is not limited to this, and if the speed reduction mechanism 35 is provided, the presence or absence of the power conversion mechanism 36 does not matter. The speed reduction mechanism 35 is not limited to the worm gear mechanism, and a speed reduction mechanism having another structure may be used.

  Furthermore, in this embodiment, the bidirectional varistor 52 is used as the capacitive element. However, the present invention is not limited to this, and a capacitor having only a function of a capacitor or a varistor may be used.

It is a perspective view which shows the wiper motor which is one embodiment of this invention. It is a cross-sectional view of the wiper motor shown in FIG. It is sectional drawing which follows the AA line in FIG. It is a perspective view which shows the detail of the brush holder shown in FIG. FIG. 2 is a power supply circuit diagram of the wiper motor shown in FIG. 1. It is a disassembled perspective view of the wiper motor shown in FIG. It is explanatory drawing which shows the fixed position to the amateur axis | shaft of an amateur core and a commutator. It is a wiring diagram of an amateur coil attached to an amateur core.

Explanation of symbols

11 Wiper motor (electric motor with reduction mechanism)
12 motor body 13 speed reducer 14 motor yoke 15 amateur 16 amateur shaft 17 bearing 18 amateur core 21 slot 22 amateur coil 23a, 23b magnet 24 commutator 24a cylindrical body 24b segment piece 24c riser 25 brush holder 25a main body wall 25b outer peripheral wall 25c Through hole 26a, 26b Brush 27a, 27b Leaf spring 28a, 28b Fastening member 31 Gear case 31a Boss part 32 Fastening member 33 Worm 34 Warm wheel 35 Deceleration mechanism 36 Power conversion mechanism 36a First arm member 36b Second arm member 37 Output Axis 38a, 38b Connecting pin 41 Power source 42 Connector portion 43 Fastening member 44a, 44b Feed terminal 45 Wiper switch 46 Feed circuit 47 Switch terminal 48 Position detection terminal 51a 51b Choke coil (noise prevention element)
52 Bidirectional varistor 53 Housing case 54 Bulkhead 55a, 55b Connection plate 56a, 56b Connection plate 57a, 57b Ground wire L1 Straight line L2 Neutral shaft

Claims (5)

An electric motor with a speed reduction mechanism comprising a motor body provided with an amateur shaft, and a speed reduction mechanism that decelerates rotation of the amateur shaft and outputs from the output shaft,
A motor yoke that rotatably supports the armature shaft;
A gear case fixed to the opening of the motor yoke and housing the speed reduction mechanism;
A pair of magnets fixed to the inner surface of the motor yoke and forming a magnetic field in the motor yoke;
An armature core comprising a plurality of slots arranged in a circumferential direction, fixed to the armature shaft, and disposed inside the motor yoke;
A commutator comprising a plurality of segment pieces arranged at predetermined intervals in the circumferential direction, and being fixed to the armature shaft with a predetermined angle offset in the rotation direction with respect to the armature core;
A plurality of amateur coils wound around the slot and connected to the corresponding segment pieces;
A pair of brushes held in a brush holder disposed inside the motor yoke and in sliding contact with the outer peripheral surface of the commutator;
An electric motor with a speed reduction mechanism, comprising a noise prevention element that is provided in a power feeding circuit connected between a power feeding terminal connected to a power source and the brush and absorbs noise generated in the power feeding circuit.   2. The electric motor with a speed reduction mechanism according to claim 1, wherein a pair of the power supply terminals are provided and disposed on the gear case, and the brush holder is provided integrally with an opening of the motor yoke from the gear case side. An electric motor with a speed reduction mechanism, comprising: a housing case that protrudes and disposed on the gear case, wherein the noise prevention element is housed in the housing case.   3. The electric motor with a speed reduction mechanism according to claim 1 or 2, wherein the commutator has an advance angle of 7 to 11 degrees with respect to the amateur core and is fixed to the armature shaft. Electric motor.   The electric motor with a speed reduction mechanism according to any one of claims 1 to 3, wherein the rotation direction of the armature shaft is set to one direction. A motor yoke formed into a cylindrical shape with a bottom by a magnetic material;
A pair of magnets arranged to face the inner surface of the motor yoke;
An amateur shaft having an armature shaft rotatably supported by a bearing provided at a bottom portion of the motor yoke, an armature core fixed to the armature shaft, and an armature coil wound around the armature core;
A commutator fixed to the armature shaft and electrically connected to the armature coil;
A pair of brushes in sliding contact with the commutator and supplying current to the commutator;
A brush holder disposed in the motor yoke, fixed to the motor yoke and holding a pair of brushes;
A speed reduction mechanism comprising a worm provided on the armature shaft and a worm wheel meshing with the worm;
A gear case fixed to the opening of the motor yoke and housing the speed reduction mechanism;
A noise prevention circuit electrically connected to the pair of brushes;
A housing case that is integrally coupled to the brush holder through the opening of the motor yoke and disposed on the outer wall of the gear case, and houses the noise prevention circuit;
In the electric motor with a speed reduction mechanism formed of an elastic metal and provided with a pair of connection plates connected to the noise prevention circuit in the housing case,
The commutator is shifted in the rotation direction with respect to the armature core so that the magnetic field generated by the armature coil is shifted from 7 degrees to 11 degrees in the rotation direction with respect to the direction perpendicular to the magnetic field generated by the pair of magnets. An electric motor with a speed reduction mechanism characterized by being fixed to the motor.

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