JP4981420B2 - Electric motor with reduction mechanism - Google Patents

Description

  The present invention relates to an electric motor with a speed reduction mechanism that includes a motor body having an armature shaft and a speed reduction mechanism that decelerates the 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 such as an automobile, an electric motor that is operated by a power source such as a battery mounted on the vehicle is often 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.

  In a wiper motor which is a kind of such an electric motor with a speed reduction mechanism, it is necessary to switch its operating speed between a low speed and a high speed in accordance with a change in the amount of raindrops adhering to the windshield. For this reason, as the wiper motor, a two-pole three-brush brush DC motor whose operation speed can be switched is often used. In a 2-pole 3-brush motor, a pair of magnets are fixed to the inner surface of the motor yoke, and an armature coil (armature winding) is attached to the slot of the armature core by lap winding, and is slid onto the commutator (commutator). As a brush to be in contact, a brush for high speed operation is provided in addition to a common brush (common brush) and a brush for low speed operation. When the low speed operation is selected by the driver's switch operation, a drive current is supplied to the amateur coil through the common brush and the low speed operation brush, and the wiper motor is operated at a low speed. On the other hand, when high-speed operation is selected by the driver, driving current is supplied to the amateur coil via the common brush and the high-speed operation brush, so that the wiper motor can be operated at high speed.

  On the other hand, a technique is known in which the motor is reduced in size and torque by increasing the number of motor poles to even poles of 4 or more. However, in a motor having four or more poles, in order to supply a driving current in a predetermined direction to each of the overwrapped armature coils, a total of four brushes including a pair of positive brushes and a pair of negative brushes are commutators. There is a problem that a large number of brushes are required and the structure around the brushes is complicated.

Therefore, for example, in the motor disclosed in Patent Document 1, an amateur coil is attached to a slot of an amateur core by wave winding to reduce the number of brushes. In other words, when the armature coil is attached to the armature core by wave winding, even if the number of motor poles is an even number of 4 or more, there are only two places where the direction of the electromotive force changes at the connection point of each armature coil. A motor can be driven by supplying a driving current in a predetermined direction to each amateur coil by a pair of brushes.
Japanese Patent No. 3469164

  However, the technique disclosed in Patent Document 1 has a problem that a multipolar motor can be driven by a pair of brushes, but the rotation speed cannot be switched.

  An object of the present invention is to provide an electric motor with a speed reduction mechanism that is multipolar and can be switched in rotation speed.

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 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 is provided on the main body and rotatably supports the armature shaft, and has an even number of four or more magnetic poles arranged in the rotation direction, and is arranged in the rotation direction with a field portion fixed to the inner surface of the motor yoke. An armature core provided with a plurality of slots, fixed to the amateur shaft, a plurality of segment pieces arranged in the rotational direction, and a commutator fixed to the amateur shaft, each mounted on the slot by wave winding, a plurality of armature coils are connected to the corresponding said segment piece, in sliding contact with the segments piece, Serial common brush supplies a driving current to the armature coil, sliding contact with the segments piece is disposed a predetermined angular displacement in the direction of rotation of the armature shaft relative to the common brush, the become the common brush and the pair amateur The segment which is shifted by a predetermined angle in the rotation direction of the armature shaft with respect to the low speed driving brush so that the electric phase does not coincide with the low speed driving brush for supplying a driving current to the coil and the low speed driving brush A high-speed operation brush that is in sliding contact with the piece and supplies a drive current to the armature coil as a pair with the common brush, and the high-speed operation brush is arranged in the rotational direction of the armature shaft, disposed in a range of wide-angle side between the low-speed operation brush, and the low-speed operation brush of the high-speed driving brush Characterized in that by energizing the displacement or the other is switchable operating speed.

With reduction gear mechanism an electric motor of the present invention, the field magnet part in providing four magnetic poles, and Turkey to place the low-speed operation brush rotation direction 90 degrees staggered in the armature shaft relative to the common brush Features.

  The electric motor with a speed reduction mechanism of the present invention is used as a drive source of a wiper device provided in a vehicle.

According to the present invention, an even number of magnetic poles of 4 or more are provided on the magnetic field portion fixed to the inner surface of the motor yoke, and the armature coil is attached to the slot of the armature core by wave winding and is paired with the common brush. In addition to the low-speed driving brush that supplies driving current to the amateur coil, the high-speed driving brush is provided with a predetermined angle shift in the rotation direction of the armature shaft with respect to the low-speed driving brush. Even if the number of poles is increased as described above, it is possible to switch the operating speed of the electric motor with the speed reduction mechanism with three brushes. Also, even if the field part is multipolarized to 4 poles or more, the operating speed of the electric motor with a speed reduction mechanism can be switched by three brushes, so the number of brushes is reduced and the structure around the brushes is simplified. Thus, the cost of the electric motor with the speed reduction mechanism can be reduced. In addition, since the high-speed operation brush is arranged in the wide-angle range between the common brush and the low-speed operation brush, a large space for arranging the high-speed operation brush is secured and the layout of each brush is improved. Can be made.

  Further, according to the present invention, four magnetic poles are provided in the field magnet portion, and the low speed operation brush is arranged 90 degrees away from the common brush in the rotation direction of the armature shaft, and the common brush, the low speed operation brush, Since the high-speed operation brush is arranged in the wide-angle range between the two, it is possible to secure a large arrangement space for the high-speed operation brush and improve the layout of each brush.

  Furthermore, when the electric motor with a speed reduction mechanism of the present invention is used as a drive source for the wiper device, the cost of the wiper device can be reduced.

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

  FIG. 1 is a front view schematically showing a wiper apparatus having a wiper motor according to an embodiment of the present invention. The vehicle 11 shown in FIG. 1 has rainwater and dust adhering to a windshield (windshield glass) 12. A wiper device 13 is provided to secure the driver's field of view by wiping off and the like. The wiper device 13 is a so-called tandem type, and wiper arms 16a and 16b are attached to two wiper shafts 15a and 15b that are rotatably supported by the vehicle body 14, respectively. Wiper blades 17a and 17b are respectively attached. A spring (not shown) is mounted on the base ends of the wiper arms 16a and 16b, and the wiper blades 17a and 17b are pressed against the windshield 12 by the spring force of the springs.

  The wiper device 13 is provided with a wiper motor 18 as an electric motor with a speed reduction mechanism as a drive source. The wiper motor 18 is fixed to the vehicle body 14, and its output shaft 18 a is connected to wiper shafts 15 a and 15 b via a link mechanism 19. When the wiper motor 18 is actuated, the wiper arms 16a and 16b are driven by the wiper motor 18 via the link mechanism 19, so that the wiper blades 17a and 17b swing in the wiping range between the upper reverse position and the lower reverse position. Thus, rainwater, dust and the like adhering to the windshield 12 are wiped off.

  2 is a cross-sectional view showing the internal structure of the wiper motor shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a winding diagram of the amateur coil shown in FIG. .

  As shown in FIG. 2, the wiper motor 18 has a motor body 22 having an armature shaft 21 and a speed reducer 24 having a speed reduction mechanism 23, and the rotation of the motor body 22, that is, the armature shaft 21 is caused by the speed reduction mechanism 23. The speed is reduced to a predetermined number of revolutions and output from the output shaft 18a.

  As shown in FIGS. 2 and 3, the motor body 22 includes a motor yoke (yoke) 25 formed of a steel material in a bottomed cylindrical shape, and four magnets 26 a to 26 d are provided on the inner surface of the motor yoke 25. Is fixed. These magnets 26a to 26d are each formed in an arc shape in cross section, and are magnetized so that the magnetic poles are directed to the inside and outside of the motor yoke 25, and the N pole and the S pole rotate toward the inside of the motor yoke 25. They are arranged side by side in the rotational direction (circumferential direction) so as to be alternately arranged in the direction. That is, on the inner surface of the motor yoke 25, the magnets 26a to 26d constitute a field part 27 having four magnetic poles arranged in the rotational direction.

  A bearing 28 is provided at the bottom of the motor yoke 25, and the armature shaft 21 is rotatably supported by the motor yoke 25 via the bearing 28. An armature core 31 is fixed to the armature shaft 21 so as to be positioned inside the motor yoke 25, and the outer peripheral surface of the armature core 31 faces the magnets 26a to 26d through a minute gap (air gap). is doing.

  The amateur core 31 is provided with 17 slots 31a to 31q arranged in the rotational direction. As shown in FIG. 4, the amateur coils 32a to 32q are respectively provided in these slots 31a to 31q by wave winding across three slots. Is installed.

  As shown in FIG. 2, a commutator (commutator) 33 is fixed to the armature shaft 21 adjacent to the armature core 31. This commutator 33 includes 17 segment pieces (commutator pieces) 33a to 33q arranged in the rotational direction in a state of being insulated from each other, and both ends of each of the amateur coils 32a to 32q are respectively corresponding segment pieces 33a. To 33q. For example, as shown by a thick line in FIG. 4, the armature coil 32e has one end connected to the segment piece 33e, passed through the slot 31g and the slot 31k, and the other end connected to the segment piece 33n. At this time, the armature coil 32e may be wound around the slot 31g and the slot 31k a plurality of times.

  As shown in FIGS. 2 and 3, the wiper motor 18 is provided with a common brush 41 and a low-speed operation brush 42 in order to supply a drive current to each of the amateur coils 32 a to 32 q at a predetermined timing. As shown in FIG. 3, these brushes 41 and 42 are respectively held by a brush holder 43 mounted inside the motor yoke 25 and are urged toward the commutator 33, that is, the segment pieces 33 a to 33 q by a spring 44. These are in sliding contact with the outer peripheral surfaces of the segment pieces 33a to 33q. Further, as shown in FIGS. 3 and 4, the low-speed operation brush 42 is disposed 90 degrees away from the common brush 41 about the axis of the armature shaft 21 in the rotation direction of the armature shaft 21. The common brush 41 is a positive electrode (positive electrode), and the low-speed operation brush 42 is a negative electrode (minus electrode). A drive current is supplied to the amateur coils 32a to 32q with the common brush 41 and the low-speed operation brush 42 as a pair. Then, the wiper motor 18 operates at a low speed.

  The wiper motor 18 is provided with a high-speed operation brush 45 as shown in FIGS. 3 and 4 so that the operation speed of the wiper motor 18 can be switched. The high-speed operation brush 45 is held by a brush holder 43 mounted inside the motor yoke 25 and is urged toward the segment pieces 33a to 33q by a spring 44 so as to be in sliding contact with the outer peripheral surfaces of the segment pieces 33a to 33q. ing. Further, the high-speed driving brush 45 is disposed with a predetermined angle α in the rotational direction of the armature shaft 21 around the axis of the armature shaft 21 with respect to the low-speed driving brush 42. Are arranged in a wide-angle range between the common brush 41 and the low-speed operation brush 42. At this time, the brush 45 for high speed operation is 90 degrees, 180 degrees, 270 degrees, 360 degrees in the rotation direction of the armature shaft 21 with respect to the common brush 41 so that the electrical phase does not coincide with the brush 42 for low speed operation. Arranged to avoid the position. The polarity of the high-speed operation brush 45 is negative (negative), and when the drive current is supplied to the amateur coils 32a to 32q with the common brush 41 and the high-speed operation brush 45 as a pair, the wiper motor 18 operates at high speed. It is supposed to be. The high speed operation is an operation state in which the rotation speed of the amateur shaft 21 is higher than the rotation speed of the amateur shaft 21 during low speed operation.

  Thus, in this wiper motor 18, since the armature coils 32a to 32q are mounted in the slots 31a to 31q of the armature core 31 by wave winding, the field portion fixed to the inner surface of the motor yoke 25 has four poles. Alternatively, the motor main body 22 can be operated by supplying a drive current to the armature coils 32a to 32q with a pair of brushes of the common brush 41 and the low speed operation brush 42 or the common brush 41 and the high speed operation brush 45. Further, by energizing either the low speed operation brush 42 or the high speed operation brush 45 which is paired with the common brush 41, the operation speed of the wiper motor 18 can be switched between the low speed operation and the high speed operation. .

  On the other hand, as shown in FIG. 2, the speed reducer 24 has a gear case 51 fixed to the motor yoke 25, and the speed reduction mechanism 23 is accommodated in the gear case 51. The armature shaft 21 of the motor body 22 projects into the gear case 51, and a worm 52 is integrally formed on the outer peripheral surface of the portion of the armature shaft 21 projecting into the gear case 51. A worm wheel 53 is rotatably accommodated in the gear case 51, the worm 52 is engaged with the worm wheel 53, and the speed reduction mechanism 23 is configured by the worm 52 and the worm wheel 53. An output shaft 18a is fixed to the central axis of the worm wheel 53, whereby the rotation of the armature shaft 21 is reduced to a predetermined rotational speed by the speed reduction mechanism 23 and output from the output shaft 18a.

  A control board 54 is accommodated inside the gear case 51 in order to control the operation of the motor body 22. The control board 54 is connected to a wiper switch (not shown) or a battery (power source) mounted on the vehicle by wiring. When the wiper switch is operated by a driver or the like, the control board 54 is connected to the common brush 41 according to the operation of the wiper switch. A drive current is selectively supplied from the control board 54 to any one of the low-speed operation brush 42 or the common brush 41 and the high-speed operation brush 45, whereby the wiper motor 18 is operated. The control board 54 is provided with a hall sensor (not shown) facing the rotation detection magnet 55 fixed to the armature shaft 21, and the control board 54 has a rotation speed detected by the hall sensor. The operation control of the wiper motor 18 is performed based on the above.

  Next, the operation of the wiper motor 18 will be described.

  When the wiper switch is operated to the low speed driving side by a driver or the like, a driving current is supplied to the amateur coils 32a to 32q from the control board 54 via the common brush 41 which is a positive pole and the low speed driving brush 42 which is a negative pole. Supplied. When a drive current is supplied to these brushes 41 and 42, a drive current corresponding to the four magnetic poles provided in the motor yoke 25 is supplied to the armature coils 32a to 32q via the commutator 33, and the wiper motor 18 operates at a low speed. Operates with. When the wiper motor 18 operates at a low speed, its rotation is decelerated to a predetermined rotational speed by the speed reduction mechanism 23 and output from the output shaft 18a, and the wiper arms 16a and 16b swing at a low speed.

  On the other hand, when the wiper switch is operated to the high-speed driving side by a driver or the like, it is driven from the control board 54 to the amateur coils 32a to 32q via the common brush 41 that is the positive pole and the high-speed driving brush 45 that is the negative pole. Current is supplied. That is, during high-speed operation, the common brush 41 and the high-speed operation brush 45 are paired to supply drive current to the amateur coils 32a to 32q. At this time, since the high-speed operation brush 45 is arranged so as to be shifted in the rotational direction of the amateur shaft 21 with respect to the low-speed operation brush 42, the conductors of the armature coils 32a to 32q between the brushes 41, 45 than during low-speed operation. The number decreases, and the armature shaft 21 of the wiper motor 18 rotates at a higher speed than during low-speed operation. When the wiper motor 18 rotates at a high speed, the rotation is decelerated to a predetermined number of rotations by the speed reduction mechanism 23 and output from the output shaft 18a, and the wiper arms 16a and 16b oscillate at a higher speed than during low speed operation. It will be.

  As described above, in the wiper motor 18, the amateur coils 32 a to 32 q are attached to the slots 31 a to 31 q of the amateur core 31 by wave winding, and the three brushes of the common brush 41, the low speed operation brush 42, and the high speed operation brush 45. Is brought into sliding contact with the commutator 33, so that the common brush 41 and the low-speed operation brush 42 or the common brush 41 may be provided even if four poles are provided in the field portion 27 fixed to the inner surface of the motor yoke 25. The driving current of the wiper motor 18 can be switched by supplying a driving current to the amateur coils 32a to 32q via any one of the pair of brushes 45 and the high-speed driving brush 45. Further, even if the field magnet portion 27 is a four-pole wiper motor 18, the rotation speed can be switched by the three brushes 41, 42 and 45, so the number of brushes is reduced and the structure around the brushes is simplified. The cost of the wiper motor 18 can be reduced. Further, in the wiper motor 18, it is not necessary to provide four brushes in accordance with the four-pole field portion 27, and only three brushes 41, 42, 45 are provided, so that the space for arranging the high-speed operation brush 45 is increased. As a result, the layout is enhanced.

  Further, in the wiper motor 18, four magnetic poles are provided in the field magnet portion 27, and the low-speed operation brush 42 is disposed with a 90-degree shift in the rotation direction with respect to the common brush 41, and the common brush 41 and the low-speed operation brush 42. Since the high-speed operation brush 45 is arranged in the wide-angle range between the two, a large space for arranging the high-speed operation brush 45 can be secured, and the layout can be further improved.

  Furthermore, since the wiper motor 18 is used as a drive source for the wiper device 13, the cost of the wiper device 13 can be reduced.

  FIGS. 5A to 5C are explanatory views showing modifications of the arrangement of the brushes for high speed operation shown in FIG.

  In the case shown in FIG. 3, the high-speed operation brush 45 is arranged in the wide-angle range between the common brush 41 and the low-speed operation brush 42, but the present invention is not limited to this, for example, as shown in FIG. As described above, the high-speed driving brush 45 has a point-symmetrical position about the axis of the amateur shaft 21 with respect to the position of the high-speed driving brush shown in FIG. You may make it arrange | position in the range of the narrow-angle side between the brush 41 and the brush 42 for low speed driving | operations.

  Further, as shown in FIG. 5B, the high-speed driving brush 45 and the armature shaft 21 are arranged with respect to the position of the high-speed driving brush 45 shown in FIG. 3 (indicated by a broken line in the drawing). You may make it arrange | position in the line-symmetrical position with respect to line segment a1 passing through the axial center.

  Further, as shown in FIG. 5 (c), the brush 45 for high speed operation is arranged with respect to the position of the brush 45 for high speed operation shown in FIG. You may make it arrange | position in the line-symmetrical position with respect to line segment a2 which passes along a heart.

  As described above, in the wiper motor 18, the motor body 22 can be operated by the pair of brushes even if the field magnet 27 is set to four poles. Therefore, the arrangement of the high-speed operation brush 45 is shown in FIG. 3 or FIG. The layout property of each brush 41, 42, 45 can be improved, such as setting to each position shown in (a) to (c).

  In FIG. 5, members corresponding to the members described above are denoted by the same reference numerals.

  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 number of magnetic poles provided in the field magnet portion 27, that is, the number of motor poles, is four. However, the present invention is not limited to this. An even number of four or more magnetic poles may be provided. In this case, the low-speed operation brush 42 is arranged in a rotational direction with respect to the common brush 41 so as to be shifted by 60 degrees for 6 poles and 45 degrees for 8 poles.

  In this embodiment, the wiper motor 18 can be switched between two speeds of low speed operation and high speed operation. However, the present invention is not limited to this, and the low speed operation brush 42 and the high speed operation brush 45 are not limited thereto. In addition to the above, a brush on the negative electrode side may be added to switch the operation speed to three or more stages.

  Furthermore, in the present embodiment, the present invention is applied to the wiper motor 18 that is a drive source of the wiper device 13, but the present invention is not limited to this, and the present invention is applied to an electric motor with a speed reduction mechanism used for other purposes. You may make it do.

It is a front view showing the outline of the wiper device provided with the wiper motor which is one embodiment of the present invention. It is sectional drawing which shows the internal structure of the wiper motor shown in FIG. It is sectional drawing which follows the AA line in FIG. FIG. 3 is a winding diagram of the amateur coil shown in FIG. 2. (A)-(c) is explanatory drawing which shows the modification of arrangement | positioning of the brush for high-speed driving | operation shown in FIG. 3, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Vehicle 12 Windshield 13 Wiper apparatus 14 Car body 15a, 15b Wiper shaft 16a, 16b Wiper arm 17a, 17b Wiper blade 18 Wiper motor (electric motor with reduction mechanism)
18a Output shaft 19 Link mechanism 21 Amateur shaft 22 Motor body 23 Reduction mechanism 24 Reduction gear 25 Motor yoke 26a-26d Magnet 27 Field part 28 Bearing 31 Amateur core 31a-31q Slot 32a-32q Amateur coil 33 Commutators 33a-33q Segment piece 41 Common brush 42 Brush for low speed operation 43 Brush holder 44 Spring 45 Brush for high speed operation 51 Gear case 52 Worm 53 Warm wheel 54 Control board 55 Magnet for rotation detection α Predetermined angle a1, a2 line segment

Claims (3)

An electric motor with a speed reduction mechanism including a motor body including an amateur shaft and a speed reduction mechanism that decelerates rotation of the amateur shaft and outputs from the output shaft,
A motor yoke provided in the motor body and rotatably supporting the armature shaft;
A field portion that includes an even number of four or more magnetic poles arranged in the rotational direction, and is fixed to the inner surface of the motor yoke;
An amateur core comprising a plurality of slots arranged in a rotational direction and fixed to the amateur shaft;
A commutator comprising a plurality of segment pieces arranged in the rotational direction and fixed to the amateur shaft;
A plurality of armature coils each attached to the slot by wave winding and connected at both ends to the corresponding segment pieces;
A common brush that slidably contacts the segment piece and supplies a drive current to the amateur coil;
Said are arranged offset a predetermined angle in the rotational direction of the armature shaft in sliding contact with the segments piece, low-speed operation brush supplies a driving current to the armature coil becomes the common brush and the pair relative to the common brush,
The segment piece is slidably contacted with the segment brush by a predetermined angle in the rotation direction of the armature shaft with respect to the low-speed operation brush so that the electric phase does not coincide with the low-speed operation brush, and is paired with the common brush. A brush for high-speed operation for supplying a driving current to the amateur coil;
The high-speed driving brush is arranged in a wide-angle range between the common brush and the low-speed driving brush in the rotation direction of the amateur shaft,
An electric motor with a speed reduction mechanism, wherein the operating speed can be switched by energizing one of the brush for low speed operation and the brush for high speed operation. The deceleration mechanism with the electric motor according to claim 1, wherein the field magnet part to provide a four pole, to place the low-speed operation brush rotation direction 90 degrees staggered in the armature shaft relative to the common brush Turkey An electric motor with a speed reduction mechanism. The electric motor with a speed reduction mechanism according to claim 1 or 2, wherein the electric motor with a speed reduction mechanism is used as a drive source of a wiper device provided in a vehicle.

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