JP2010001010A - Wiper motor and wiper device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a wiper motor adapted to surely transmit the rotation of a motor body to an output shaft while reducing the rotation speed; and a wiper device equipped with the wiper motor. <P>SOLUTION: The wiper motor 10 is provided with: a ring gear 48 having an internal teeth 48A; a planetary gear 50 having at a circumferential part thereof an external teeth 50A engaged with the internal teeth 48A of the ring gear 48, and having a pitch circle diameter larger than the pitch circle radius of the ring gear 48; a motor body part 10A having an armature shaft 14 disposed coaxially with the ring gear 48 and eccentrically coupled to the planetary gear 50; a motor output shaft 36 supported rotatably around an axis parallel to the armature shaft 14; and a rotation ejection mechanism 56 for ejecting rotation from motion accompanied by the revolution and rotation of the planetary gear 50, and converting the rotation to the rotation of the motor output shaft 36. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wiper motor and a wiper device.

  A flexible transmission element is provided on the outer periphery of the elliptical rotor via a roller bearing, and the outer teeth of the transmission element are fixed to the both ends of the long-diameter portion of the elliptical rotor with a fixed ring and an output having different numbers of teeth. A wiper motor having a speed reduction mechanism engaged with each ring is known (for example, see Patent Document 1).

Japanese National Patent Publication No. 11-508855

  However, in the conventional technology as described above, since the teeth of the flexible transmission element are meshed with the fixing ring and the output ring, the meshing between the transmission element, the fixing ring, and the output ring during overload, etc. There is a concern that this may occur.

  In view of the above facts, an object of the present invention is to obtain a wiper motor that can reliably transmit the rotation of the motor body to the output shaft while decelerating the rotation of the motor body, and a wiper device including the wiper motor.

  According to a first aspect of the present invention, there is provided a wiper motor having a ring gear having inner teeth and outer teeth meshed with the inner teeth of the ring gear in a part in the circumferential direction, and a pitch circle having a diameter of the pitch circle of the ring gear. A planetary gear that is larger than the radius of the motor, and a motor body that is arranged coaxially with one of the ring gear and the planetary gear and has a rotating shaft that is eccentrically connected to the other of the ring gear and the planetary gear. An output shaft supported so as to be able to rotate about an axis parallel to the rotation axis of the motor body, and a rotation conversion mechanism that converts the other rotation of the ring gear and the planetary gear to the rotation of the output shaft. ing.

  In the wiper motor according to claim 1, when the rotating shaft of the motor body rotates, the ring gear or the planetary gear that is eccentrically connected to the rotating shaft changes the meshing position with the counterpart gear in the circumferential direction while rotating the shaft of the rotating shaft. Rotates while revolving around the heart. From the movement accompanying the revolution and rotation of the ring gear or planetary gear, only the rotation (component) is transmitted to the output shaft by the rotation conversion mechanism. That is, the rotation of the ring gear or the planetary gear is converted to the rotation of the output shaft. Thereby, the rotation of the rotating shaft is decelerated and transmitted to the output shaft.

  Here, the present wiper motor has a differential gear in which a ring gear and a planetary gear mesh with each other as a reduction mechanism, so that rotation (torque) can be reliably transmitted. In addition, since the diameter of the pitch circle of the planetary gear is larger than the radius of the pitch circle of the link gear, the strength of the outer teeth of the planetary gear and the inner teeth of the ring gear can be ensured. That is, it is possible to set the outer teeth of the planetary gear and the inner teeth of the ring gear to a dimension and shape having sufficient strength against overload.

  Thus, in the wiper motor according to the first aspect, the rotation of the motor body can be reliably transmitted to the output shaft while decelerating.

  A wiper motor according to a second aspect of the present invention is the wiper motor according to the first aspect, wherein the diameter of the tip circle of the planetary gear is larger than the diameter of the tip circle of the ring gear.

  In the wiper motor according to claim 2, the diameter (maximum diameter) of the tip circle of the planetary gear which is an external gear is larger than the diameter (minimum diameter) of the tip circle of a ring gear which is an internal gear. It is easier to secure the strength of the outer teeth of the gear and the inner teeth of the ring gear.

  According to a third aspect of the present invention, in the wiper motor according to the first or second aspect, the rotating shaft of the motor body and the output shaft are arranged coaxially.

  In the wiper motor according to claim 3, since the rotation shaft of the motor body, that is, the revolution shaft of the ring gear or the planetary gear, and the output shaft are arranged coaxially, the rotation conversion mechanism causes rotation accompanied by the revolution of the ring gear or the planetary gear. Efficiently converted to output shaft rotation.

  The wiper motor according to a fourth aspect of the present invention is the wiper motor according to any one of the first to third aspects, wherein the rotation conversion mechanism is at least partially circumferentially disposed on the other of the ring gear and the planetary gear. A plurality of engaging portions provided at unequal intervals and a plurality of engaging members and a rotating member that rotates in synchronization with the output shaft are provided so that at least a part thereof is unequally spaced in the circumferential direction. Each of the engaging portions is configured to have an engaged portion capable of taking a state where the engaging portion is engaged in the circumferential direction and a state where the engaging portion is not engaged.

  In the wiper motor according to claim 4, since the plurality of engaging portions and the engaged portion are provided, a set of the engaging portion and the engaged portion that are engaged according to the revolution position of the ring gear or the planetary gear is provided. While changing, the output shaft or the rotating member (that is, the output shaft) is rotated at a substantially constant speed. The rotating member may rotate integrally with the motor output shaft. Here, since at least a part of the plurality of sets of engaging portions and engaged portions are arranged at unequal intervals in the circumferential direction, torque fluctuations due to the motor body, and the engaging portions and the engaged portions in the rotation conversion mechanism Synchronizing (resonating) with fluctuations in the torque transmission rate associated with a change in the set engaged with the portion is suppressed.

  A wiper motor according to a fifth aspect of the present invention is the wiper motor according to any one of the first to third aspects, wherein a plurality of the rotation conversion mechanisms are provided at equal intervals in the circumferential direction on the other of the ring gear and the planetary gear. A plurality of engaging portions, and a plurality of rotating members that rotate in synchronization with the output shaft or the output shaft at equal intervals in the circumferential direction. And an engaged portion that can take a state of not being configured.

  In the wiper motor according to claim 5, since the plurality of engaging portions and the engaged portions are arranged at equal intervals in the circumferential direction, the engaging portion and the engaged portion that are engaged according to the revolution position of the ring gear or the planetary gear. The pair with the joint changes, and the output shaft or the rotating member (that is, the output shaft) is rotated at a substantially constant speed. The rotating member may rotate integrally with the motor output shaft.

  A wiper motor according to a sixth aspect of the present invention is the wiper motor according to the fourth or fifth aspect, wherein the number of the engaging portions and the engaged portions is an odd number.

  In the wiper motor according to the sixth aspect, since the number of sets of the engaging portion and the engaged portion is an odd number, a variation in torque transmission from the motor body to the output shaft is suppressed as compared with an even number.

  The wiper motor according to a seventh aspect of the present invention is the wiper motor according to any one of the fourth to sixth aspects, wherein the number of the engaging portions and the engaged portions is the number of slots constituting the motor body. On the other hand, it is a number having no common divisor other than 1.

  In the wiper motor according to claim 7, since the number of sets of the engaging portion and the engaged portion does not have a common divisor other than 1 with respect to the number of slots of the motor main body, torque fluctuation due to the motor main body and rotation Synchronous (resonant) fluctuations in the torque transmission rate associated with a change in the pair of engaging portions and engaged portions in the conversion mechanism are suppressed.

  The wiper motor according to an eighth aspect of the present invention is the wiper motor according to any one of the first to seventh aspects, wherein the output unit or a detection unit provided on a rotating member that rotates in synchronization with the output shaft or A rotation position detection mechanism for detecting a rotation position of the output shaft is further provided.

  In the wiper motor according to the eighth aspect, since the rotational position detection mechanism is provided on the output shaft or a member that rotates in synchronization with the output shaft (including the output shaft side member of the rotation conversion mechanism), the revolution component is mechanically removed. The rotational position can be detected with high accuracy by removing. The rotating member may rotate integrally with the motor output shaft.

  A wiper motor according to a ninth aspect of the present invention is the wiper motor according to any one of the first to eighth aspects, wherein the wiper motor is disposed between the motor body on the rotating shaft and the other of the ring gear and the planetary gear. And a balance weight for canceling an unbalance associated with the other revolution of the ring gear and the planetary gear on the rotating shaft.

  In the wiper motor according to the ninth aspect, since the balance weight is disposed between the motor body and the speed reduction mechanism in the axial direction of the rotating shaft, the unbalance accompanying the revolution of the ring gear or the planetary gear is efficiently canceled (cancelled). )

  A wiper motor according to a tenth aspect of the present invention is the wiper motor according to the ninth aspect, wherein a maximum eccentric position of the balance weight with respect to the axis of the rotary shaft is a plurality of teeth constituting a slot of the motor body. It is offset in the circumferential direction with respect to the circumferential center line.

  In the wiper motor according to claim 10, since the maximum eccentric position of the balance weight is offset in the width direction with respect to the center line in the width direction of the tooth portion (portion forming the slot) of the motor body, the torque fluctuation of the output shaft is It is suppressed.

  The wiper device according to an eleventh aspect of the present invention is the wiper device according to any one of the first to tenth aspects, wherein a pivot shaft for transmitting a driving force to the wiper arm and the output shaft are arranged in parallel to the pivot shaft. The wiper motor described above, and a link mechanism that is disposed on the same side in the axial direction with respect to the wiper motor and the pivot shaft, and that converts the rotation of the output shaft into the swing of the pivot shaft.

  In the wiper device according to claim 11, since the wiper motor has the speed reduction mechanism in which the inner teeth of the ring gear and the outer teeth of the planetary gear are meshed, the wiper motor is configured compactly in the axial direction of the rotating shaft, that is, the output shaft. be able to. Since the output shaft of the wiper motor and the pivot shaft are disposed substantially in parallel, and the link mechanism is disposed on the same side in the axial direction with respect to the output shaft and the pivot shaft, the wiper device as a whole is output from the wiper motor. It can be configured compactly in the axial direction of the shaft.

  A wiper device according to a twelfth aspect of the invention is the wiper device according to the eleventh aspect, wherein a pivot holder portion that rotatably supports the pivot shaft and at least a part of a housing of the wiper motor are integrally formed. Yes.

  In the wiper device according to the twelfth aspect, since the motor body and the speed reduction mechanism in the wiper motor are arranged substantially coaxially, the housing shape of the wiper motor can be formed into a simple shape. For this reason, the structure by which the pivot holder part was integrally formed in at least one part of this housing can be obtained easily.

It is a figure which shows the wiper motor which concerns on the 1st Embodiment of this invention, Comprising: (A) is a sectional side view, (B) is an axial orthogonal sectional view along the 1B-1B line | wire of FIG. 1 (A). It is a schematic diagram of the speed-reduction mechanism part which comprises the wiper motor which concerns on the 1st Embodiment of this invention. FIG. 3 is a cross-sectional view perpendicular to the axis along line 3-3 in FIG. 1A, showing the rotational position detection mechanism constituting the wiper motor according to the first embodiment of the present invention. 1 is a partially cutaway front view showing a wiper device according to a first embodiment of the present invention. It is the partially cutaway front view which shows the wiper apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the modification of the differential reduction mechanism which comprises the wiper motor which concerns on embodiment of this invention, Comprising: (A) is an axial orthogonal cross-sectional view which shows a 1st modification, (B) shows a 2nd modification. FIG. It is a figure which shows the 1st modification of the rotational position detection mechanism which comprises the wiper motor which concerns on embodiment of this invention, Comprising: (A) is a sectional side view, (B) is the 7B-7B line | wire of FIG. 7 (A). FIG. It is a figure which shows the 2nd modification of the rotational position detection mechanism which comprises the wiper motor which concerns on embodiment of this invention, Comprising: (A) is a sectional side view, (B) is the 8B-8B line | wire of FIG. 8 (A). FIG. It is a schematic diagram which shows the modification of the deceleration mechanism part which comprises the wiper motor which concerns on embodiment of this invention. FIG. 6 is a cross-sectional view perpendicular to an axis showing a differential reduction mechanism constituting a wiper motor according to a third embodiment of the present invention. It is a diagram which shows the relationship between the number of the engagement parts of the engagement protrusion and the engagement hole in the rotation taking-out mechanism which comprises the wiper motor which concerns on embodiment of this invention, and a torque transmission fluctuation range. It is a figure for demonstrating the torque fluctuation | variation of the wiper motor which concerns on embodiment of this invention, Comprising: (A) is a diagram which shows the torque fluctuation | variation by the electrical factor of a motor main body, (B) is a mechanical factor of a rotation taking-out mechanism. (C) is a diagram which shows the torque fluctuation | variation as the whole wiper motor. It is a schematic diagram which shows the principal part of the wiper motor which concerns on the 5th Embodiment of this invention. It is a diagram which shows the relationship between the position with respect to the slot of the counterweight in the wiper motor which concerns on embodiment of this invention, and a torque fluctuation.

  A wiper motor 10 according to a first embodiment of the present invention and a wiper device 11 including the wiper motor 10 will be described with reference to FIGS. First, the wiper motor 10 will be described, and then the wiper device 11 will be described.

(Configuration of wiper motor)
1A shows a wiper motor 10 in a side cross-sectional view, and FIG. 1B shows a cross-sectional view perpendicular to the axis along line 1B-1B in FIG. 1A. Yes. As shown in FIG. 1A, the wiper motor 10 includes a motor main body 10A and a speed reduction mechanism 10B as main parts.

  The motor body 10A includes a yoke 12 formed in a substantially bottomed cylindrical shape. The yoke 12 pivotally supports one end in the axial direction of the armature shaft 14 as a rotating shaft via a bearing 16 disposed at the shaft center portion of the bottom portion 12A. The other end side of the armature shaft 14 in the axial direction protrudes from the speed reduction mechanism portion 10B and is configured to be rotatably supported by the speed reduction mechanism portion 10B (described later).

  In the yoke 12, an armature 18 as an armature is accommodated. The armature 18 is configured by winding a coil (coil) 18B around a core (iron core) 18A that is coaxially fixed to the armature shaft 14. In addition, a pair of magnets 20 that are opposed to the outer peripheral surface of the armature 18 are fixed to the inner peripheral surface of the cylindrical portion 12 </ b> B of the yoke 12.

  The armature 18 is provided with a commutator 22 as a commutator. Although details will be described later, the commutator 22 has a plurality of segments 22 </ b> A arranged at equal intervals in the circumferential direction and formed in a substantially cylindrical or annular shape as a whole, and is coaxially fixed to the armature shaft 14. An insulating portion (not shown) is disposed between the segments 22A adjacent in the circumferential direction. Each segment 22A is electrically connected to a corresponding winding 18B of the armature 18 (not shown).

  Further, a pair of brushes 24 are disposed in the yoke 12 so as not to rotate with respect to the yoke 12. Specifically, as shown in FIG. 1A, each brush 24 can be brought into and out of contact with the segment 22A (the outer peripheral surface of the commutator 22) in a brush holder portion 26 arranged symmetrically with respect to the axis of the commutator 22. And is biased by the spring 28 toward the commutator 22 (inward in the radial direction). Thereby, each brush 24 is always in contact with the segment 22 </ b> A of the commutator 22.

  In this embodiment, the pair of brush holder portions 26 are formed integrally with a brush holder 30 held between the yoke 12 and a speed reduction mechanism portion 10B (a gear housing described later). Each brush 24 is connected to a power supply wiring (not shown). As a result, in the motor main body 10A, the commutator 22 rotates around the axis (relatively rotating with respect to the yoke 12, that is, the brush 24), so that commutation is performed while the commutator 22 and the brush 24 are in sliding contact with each other. The armature current is configured to flow through.

  As described above, the motor body 10A of the wiper motor 10 according to the first embodiment is a magnet type DC motor. In this embodiment, the motor body 10A is configured as a flat type motor having a short axial dimension.

  The speed reduction mechanism portion 10B includes a gear housing 32 connected to the opening end side of the yoke 12 (the other end side in the axial direction of the armature shaft 14). The gear housing 32 is formed in a substantially bottomed cylindrical shape having a bottom portion 32A and a cylindrical portion 32B, and an opening of the yoke 12 is formed at a flange portion 32C extending radially outward from the opening end of the cylindrical portion 32B. It is joined by a screw 34 to a flange portion 12C extending radially outward from the end. Although detailed description is omitted, the brush holder 30 is fixedly held to the yoke 12 in a joined state of the yoke 12 and the gear housing 32.

  The speed reduction mechanism unit 10 </ b> B includes a motor output shaft 36 as an output shaft and a differential speed reduction mechanism 38 that decelerates the rotation of the armature shaft 14 and transmits it to the motor output shaft 36. The motor output shaft 36 passes through a boss portion 40 provided at the shaft center portion of the bottom portion 32 </ b> A of the gear housing 32, and a tip end portion 36 </ b> A protrudes outside the motor, and a base end portion 36 </ b> B is in the gear housing 32. Is arranged. An axial direction intermediate portion 36 </ b> C of the motor output shaft 36 is rotatably supported by the boss portion 40, that is, the gear housing 32 via a bearing 42.

  Further, a recess 44 having a cylindrical inner peripheral surface is coaxially formed in the base end portion 36B of the motor output shaft 36, and the distal end 14A of the armature shaft 14 is inserted into the recess 44. . In this embodiment, a bearing 46 is provided between the tip 14 </ b> A of the armature shaft 14 and the inner peripheral surface of the recess 44. Thereby, the armature shaft 14 and the motor output shaft 36 are connected to each other so as to be rotatable relative to each other coaxially. In other words, the tip end 14A (the other end in the axial direction) of the armature shaft 14 can be regarded as being rotatably supported by the gear housing 32, that is, the yoke 12, via the motor output shaft 36.

  As shown in FIG. 1B, the differential reduction mechanism 38 includes a ring gear 48 having inner teeth 48A and a planetary gear 50 as a planetary gear having outer teeth 50A meshing with the inner teeth 48A of the ring gear 48. I have. In this embodiment, the ring gear 48 is formed integrally with the cylindrical portion 32 </ b> B of the gear housing 32 so as to be arranged coaxially with the armature shaft 14 and the motor output shaft 36. That is, the ring gear 48 in this embodiment is a fixed element that is not rotatable relative to the gear housing 32.

  As shown in FIGS. 1 (A) and 1 (B), the planetary gear 50 is arranged eccentrically by an eccentric amount ax with respect to the ring gear 48, and its outer teeth 50A are internal teeth 48A of the ring gear 48 in a part of the circumferential direction. Is engaged. An external tooth 50A of the planetary gear 50 that is 180 ° away from the meshing portion with the ring gear 48 is located on the opposite side of the meshing portion with respect to the axis of the planetary gear 50 (armature shaft 14). That is, although not shown, the diameter of the pitch circle of the planetary gear 50 is made larger than the radius of the pitch circle of the ring gear 48.

  In this embodiment, the diameter of the tip circle of the planetary gear 50 is larger than the diameter of the tip circle of the ring gear 48. Thereby, in the differential reduction mechanism 38, the tooth tip of the external tooth 50A is slightly separated from the tooth tip of the internal tooth 48A at a position of 180 ° with respect to the meshing portion of the planetary gear 50 with the ring gear 48. Yes.

  The planetary gear 50 is connected to the armature shaft 14 so as to rotate or revolve around the axis AL while maintaining the eccentricity ax relative to the axis AL as the armature shaft 14 rotates about the axis AL. Yes. Specifically, an eccentric shaft portion 52 having an eccentric axis EL that is eccentric by an eccentric amount ax with respect to the axis AL of the armature shaft 14 is formed in a portion of the armature shaft 14 that is located in the gear housing 32. The planetary gear 50 is fixed to the eccentric shaft portion 52 via a bearing 54 so as to be coaxial and relatively rotatable.

  Therefore, the planetary gear 50 is configured to revolve around the axis AL by rotation of the armature shaft 14 around the axis AL, and to allow rotation around the own axis (eccentric axis EL), that is, rotation. As described above, the planetary gear 50 meshed with the inner teeth 48A of the ring gear 48, whose outer teeth 50A are fixed elements, revolves around the axis AL as the armature shaft 14 rotates (the meshing area with the ring gear 48 is changed). While rotating in the circumferential direction of the ring gear 48, it rotates around the eccentric axis EL.

  The speed reduction mechanism unit 10B selectively takes out the rotation of the planetary gear 50 from the movement of the planetary gear 50 about the axis AL of the armature shaft 14 and the rotation about the eccentric axis EL, and rotates around the axis AL of the motor output shaft 36. A rotation take-out mechanism (Oldham mechanism) 56 is provided as a rotation conversion mechanism for transmitting the rotation as a rotation.

  The rotation take-out mechanism 56 includes a plurality of (eight in this embodiment) engagement protrusions 58 as projecting portions protruding from the end surface of the planetary gear 50 on the motor output shaft 36 side, and a base end portion 36B of the motor output shaft 36. And a plurality of engagement holes 62 serving as engaged portions, each of which is provided in a flange portion 60 serving as a rotating member extending radially outward from each other and into which engagement protrusions 58 are inserted one by one. ing. In this embodiment, the plurality of engaging protrusions 58 are arranged at equal intervals in the circumferential direction along a virtual circumference that is coaxial with the planetary gear 50 (with the eccentric axis EL as the axis). The plurality of engagement holes 62 are arranged at equal intervals in the circumferential direction along a virtual circumference coaxial with the flange portion 60 (motor output shaft 36).

  Moreover, in this embodiment, each engagement protrusion 58 is formed in the short cylinder shape which comprises circular shape by the axial direction view of the armature shaft 14. As shown in FIG. On the other hand, each engagement hole 62 has a circular shape when viewed in the axial direction of the armature shaft 14, and the inner diameter thereof is larger than the outer diameter of the engagement protrusion 58. The difference in the inner diameter of the engagement hole 62 with respect to the outer diameter of the engagement protrusion 58 depends on the movement locus Lp of the engagement protrusion 58 accompanying the rotation of the planetary gear 50 shown in FIG. 1B and the rotation of the motor output shaft 36. It is set so that the difference with the movement locus Lo of the accompanying engagement hole 62 can be absorbed. Note that the movement locus Lp described above indicates the movement locus of the engaging protrusion 58 when the revolution of the planetary gear 50 is omitted and the eccentric axis EL is fixed for convenience.

  In the rotation take-out mechanism 56 described above, a set of engagement protrusions 58 and a flange part 60 transmit rotation from the planetary gear 50 to the motor output shaft 36 (flange part 60), and the engagement protrusions 58 transmit the rotation. The set with the engagement hole 62 is configured to be sequentially switched according to the revolution position and the rotation position of the planetary gear 50.

  As a result, in the speed reduction mechanism unit 10B, the rotation component of the planetary gear 50 is extracted by the rotation extraction mechanism 56 from the movement of the planetary gear 50 involving the revolution about the axis AL and the rotation about the eccentric axis EL, and the axis of the motor output shaft 36 is extracted. It is a structure converted into rotation around the AL. Thus, the speed reduction mechanism unit 10B including the differential speed reduction mechanism 38 and the rotation extraction mechanism 56 can be modeled as schematically shown in FIG.

  Further, the wiper motor 10 includes a counterweight (balance weight) 55 for canceling an imbalance that occurs when the planetary gear 50 revolves around the axis AL of the armature shaft 14. The counterweight 55 is fixed so as to rotate integrally with the motor main body 10 </ b> A side with respect to the planetary gear 50 in the eccentric shaft portion 52 of the armature shaft 14. In other words, the counterweight 55 can be regarded as being disposed between the motor body 10A and the differential reduction mechanism 38 (deceleration mechanism 10B).

  Further, the reduction mechanism unit 10B is provided with a rotation position detection mechanism 64 for detecting the rotation position of the motor output shaft 36. The rotation position detection mechanism 64 includes a sensor magnet 66 as a detected portion provided so as to rotate coaxially and integrally with the flange portion 60, and a magnetic pole of the sensor magnet 66 as the flange portion 60, that is, the motor output shaft 36 rotates. A magnetic sensor 68 serving as a detection unit that outputs a signal corresponding to a change is used as a main part to constitute a non-contact rotational position detection mechanism.

  As shown in FIG. 3, the sensor magnet 66 has a plurality of (three in this embodiment) unit magnets each formed in an annular shape, including an inner ring magnet 66A, an intermediate ring magnet 66B, and an outer ring magnet 66C. Configured. These inner ring magnet 66A, intermediate ring magnet 66B, and outer ring magnet 66C have magnetized patterns (one or each of a plurality of N poles and S poles surrounding each other so as to have different patterns with respect to the corresponding magnetic sensor 68. Pattern formed alternately in the direction).

  The sensor magnet 66 is, for example, a so-called plastic magnet (so-called bond magnet) configured by including a magnetic powder in a resin material, and includes a ring magnet 66A, an intermediate ring magnet 66B, an outer ring magnet 66C (the connection between them). Each part including the part is integrally formed.

  As shown in FIG. 1A, the magnetic sensor 68 includes three Hall elements 68A, 68B, and 68C corresponding to the inner ring magnet 66A, the intermediate ring magnet 66B, and the outer ring magnet 66C. Each Hall element 68A, 68B, 68C is mounted on a circuit board 70 fixed to the gear housing 32, and its output signal is output to a control device (not shown) provided on the circuit board 70.

  Although a detailed description is omitted, the rotational position detection mechanism 64 includes an inner ring magnet 66A, an intermediate ring magnet 66B, and an outer ring magnet 66C according to the rotational position of the motor output shaft 36 with respect to the yoke 12, that is, the applied vehicle body. Based on signals from the hall elements 68A, 68B, 68C corresponding to the magnetization pattern, for example, the retracted position, the lower inversion position, the upper inversion position, and the like of the wiper blade are detected.

  The wiper motor 10 described above is fixed to a frame 72 (see FIG. 4) of the wiper device 11 to constitute the wiper device 11. In this embodiment, as shown in FIG. 1A, a plurality of screw boss portions 74 are formed on the bottom portion 32 </ b> A of the gear housing 32 as attachment portions for fixing the wiper motor 10 to the frame 72.

(Configuration of wiper device)
FIG. 4 is a front view of the wiper device 11 having the wiper motor 10 partially cut away. As shown in this figure, the wiper motor 10 is fixedly fastened to the frame 72 by screws 76 screwed into a plurality of screw boss portions 74. The frame 72 is provided with a pair of pivot holders 78 and 80.

  The pivot holder 78 pivotally supports a first pivot shaft 84 connected to the first wiper arm 82 with respect to the vehicle body, and the pivot holder 80 includes a second pivot shaft 88 connected to the second wiper arm 86. Is pivotally supported with respect to the vehicle body. One of the first wiper arm 82 and the second wiper arm 86 is a wiper arm for a driver seat, and the other is a wiper arm for a passenger seat.

  As shown in FIG. 4, in the wiper device 11, the pair of first pivot shaft 84, second pivot shaft 88, and motor output shaft 36 are disposed substantially in parallel. Further, in this embodiment, the pair of first pivot shaft 84 and second pivot shaft 88 are disposed toward one side (upper side) in the axial direction, whereas the motor output shaft 36 is disposed on the other side in the axial direction. It is arranged toward the side (lower side). In other words, the first pivot shaft 84, the second pivot shaft 88, and the motor output shaft 36 are disposed so as to be relatively oriented in a substantially 180 ° direction (opposite direction).

  Further, the wiper device 11 includes a link mechanism 90 for converting the rotation of the motor output shaft 36 into the swinging (reciprocating rotation) of the first pivot shaft 84 and the second pivot shaft 88. The link mechanism 90 has a crank arm 92 connected at one end so as to rotate integrally with the motor output shaft 36, a first pivot lever 94 connected at one end so as to rotate integrally with the first pivot shaft 84, and A second pivot lever 96 having one end connected to rotate integrally with the second pivot shaft 88, one end connected to the other end of the crank arm 92 via a ball joint 98, and the other end to the second pivot lever. The other end of the first link 100 is connected to the other end of the second pivot lever 96 via the ball joint 98 and the other end of the first pivot lever 94 is connected to the other end of the second pivot lever 96. The second link 102 connected to the other end via a ball joint 98 is a main part.

  As a result, the wiper device 11 is provided with the wiper motor 10, the first pivot shaft 84 (first wiper arm 82), and the second pivot shaft 88 (second wiper arm 86) on one side with respect to the frame 72. A link mechanism 90 is disposed on the other side. In the wiper device 11, the rotation of the crank arm 92 accompanying the rotation of the motor output shaft 36 is converted into the swing of the second pivot lever 96 connected via the first link 100, and the second pivot. The swing of the lever 96 is transmitted as the swing of the first pivot lever 94 connected via the second link 102.

  As described above, the wiper device 11 includes the wiper motor 10, the first pivot shaft 84 (first wiper arm 82), the second pivot shaft 88 (second wiper arm 86), and the link on the frame 72 provided with the pivot holders 78 and 80. A module-type wiper device in which the mechanism 90 is assembled is provided.

  Next, the operation of the first embodiment will be described.

  In the wiper apparatus 11 to which the wiper motor 10 having the above configuration is applied, when the wiper motor 10 is operated and the motor output shaft 36 rotates, the rotation of the motor output shaft 36 is rotated by the link mechanism 90 by the first pivot lever 94 and the second pivot. It is converted into the swing of the lever 96. Then, the first pivot shaft 84 and the second pivot shaft 88 reciprocate around the respective axes, and the connected first wiper arm 82 and second wiper arm 86 are swung within a predetermined angular range. Thereby, in the wiper device 11, the wiper blades of the first wiper arm 82 and the second wiper arm 86 are reciprocated between the upper and lower inversion positions of the windshield glass, and wipe the windshield glass.

  Here, the wiper motor 10 constituting the wiper device 11 is a difference for decelerating and transmitting the rotation from the armature shaft 14 arranged substantially parallel to the motor output shaft 36 to the motor main body 10A which is a flat type motor. Since the decelerating mechanism unit 10B having the dynamic decelerating mechanism 38 is combined, it is thin as a whole in the axial direction.

  Specifically, since the speed reduction mechanism portion 10B includes a differential speed reduction mechanism 38 configured by disposing the planetary gear 50 along substantially the same plane inside the ring gear 48, the speed reduction mechanism portion 10B is connected to the axis of the armature shaft 14. It can be configured compactly in the direction. Further, in the wiper motor 10, the movement of the planetary gear 50 is converted into the rotation of the motor output shaft 36 by the engagement protrusion 58 provided in the planetary gear 50 and the engagement hole 62 provided in the flange portion 60 (motor output shaft 36). Since the rotation take-out mechanism 56 is configured, the speed reduction mechanism portion 10 </ b> B including the rotation take-out mechanism 56 can be configured compactly in the axial direction of the armature shaft 14.

  As described above, the wiper motor 10 has a smaller projected area as seen from the axial direction of the motor output shaft 36 than a wiper motor provided with a speed reduction mechanism that transmits rotation between staggered axes such as a worm speed reduction mechanism. In addition, the weight can be reduced, and in such a small and lightweight configuration, the armature shaft 14 can be further compactly configured (thinned) in the axial direction. Further, in the wiper motor 10, both the armature shaft 14 and the differential reduction mechanism 38 have a radial generated in the bearings 16, 46, etc., as compared with a wiper motor having a reduction mechanism that transmits rotation between staggered shafts such as a worm reduction mechanism. Friction loss due to load is greatly reduced, and its deceleration efficiency is greatly improved.

  In addition, since the wiper motor 10 includes the differential reduction mechanism 38 in which the diameter of the tip circle of the planetary gear 50 is larger than the diameter of the tip circle of the ring gear 48 as a reduction mechanism, while maintaining a required reduction ratio, The inner teeth 48A of the ring gear 48 and the outer teeth 50A of the planetary gear 50 can be set to a dimension and shape having sufficient strength against overload.

  For example, in a configuration in which the motor main body has a low torque and a high rotation speed and a high reduction ratio in order to reduce the size, it is necessary to reduce the gear module (increase the number of teeth). There is a concern that the strength against the load is insufficient. Further, even in a configuration using a toothed flexible member for the speed reduction mechanism, there is a concern that the strength of the meshing portion against overload or the like is insufficient. In particular, when the gear or the flexible member is made of a resin material, synthetic rubber, or the like, there is a concern that the strength may be reduced due to heat generation accompanying power transmission. On the other hand, in the wiper motor 10, the required rotational speed of the motor output shaft 36 can be obtained by the differential reduction mechanism 38 using the flat motor body 10 </ b> A that is a relatively low rotation type. The strength of the differential reduction mechanism 38, that is, the required wiper performance, can be ensured while achieving a reduction in size and thickness as a whole.

  Thus, in the wiper motor 10 according to the first embodiment, the rotation of the motor body 10A can be reliably transmitted to the motor output shaft 36 while decelerating. The rotation of the motor output shaft 36 obtained through the differential reduction mechanism 38 is not a complete constant speed rotation but a rotation having a slight speed fluctuation. This speed fluctuation cancels the resonance generated from the wiper device 11, and the vibration of the wiper device can be prevented.

  Further, in the wiper motor 10, since the motor output shaft 36 is provided coaxially with the armature shaft 14, the projected area viewed from the axial direction of the motor output shaft 36 is further reduced, that is, further miniaturization is achieved. .

  Further, in the wiper motor 10, since the rotation take-out mechanism 56 is configured by a plurality of engagement protrusions 58 and engagement holes 62, the speed variation of the motor output shaft 36 is small. In particular, in the wiper motor 10, the motor output shaft 36 is provided coaxially with the armature shaft 14 as described above, and the rotation take-out mechanism 56 is configured by a large number (eight each) of the engagement protrusions 58 and the engagement holes 62. Therefore, the motor output shaft 36 can be driven at a substantially constant speed regardless of the position in the circumferential direction.

  Furthermore, in the wiper motor 10, since the sensor magnet 66 constituting the rotational position detection mechanism 64 is provided in the flange portion 60, in other words, coaxially and integrally with the motor output shaft 36 in the rotation extraction mechanism 56 (synchronized) Since the sensor magnet 66 is provided in the rotating portion, the rotational position of the motor output shaft 36 can be detected well without being affected by the revolution of the planetary gear 50.

  In the wiper motor 10, the counterweight 55 is disposed between the motor body 10 </ b> A and the planetary gear 50 (the differential reduction mechanism 38), so that the imbalance associated with the revolution of the planetary gear 50 can be effectively canceled (cancelled). be able to. Further, the counterweight 55 suppresses the wear powder generated by the sliding of the brush 24 and the commutator 22 from entering the meshing portion of the differential reduction mechanism 38 from the motor main body 10A. Further, the counterweight 55 prevents the lubricant of the differential reduction mechanism 38 from entering the sliding contact portion between the commutator 22 and the brush 24. As a result, it is possible to prevent or effectively suppress abnormal wear of the meshing portion of the differential reduction mechanism 38 and the sliding contact portion between the commutator 22 and the brush 24.

  Here, the wiper device 11 including the wiper motor 10 as described above is reduced in size (projection area of the armature shaft 14 in the axial direction) and reduced in thickness. The mountability is good and the mounting space is small. These contribute to the expansion of the cabin space and the engine space of the applied vehicle. In addition, the above-described reduction in weight associated with the reduction in size and thickness of the wiper motor 10 contributes to improved fuel consumption (reduced CO2 emissions) of the applied vehicle.

  Further, in the wiper device 11, the first pivot shaft 84, the second pivot shaft 88, and the motor output shaft 36 are arranged in a posture that is substantially parallel to each other and relatively oriented in the direction of about 180 ° (opposite direction). The link mechanism 90 (each link, arm, lever) constituting the link mechanism 90 can be configured substantially horizontally. Therefore, the torque generated by the wiper motor 10 can be efficiently converted into the swing of the first pivot shaft 84 (first wiper arm 82) and the second pivot shaft 88 (second wiper arm 86).

  In addition, since the wiper motor 10 is disposed between the pair of pivot holders 78 and 80, the wiper device 11 has a compact configuration in the axial direction of the wiper motor 10 (motor output shaft 36) as a whole. Therefore, the wiper device 11 has better mountability to the applied vehicle and can further reduce the mounting space.

(Other embodiments)
Next, another embodiment of the present invention will be described. The same reference numerals as those in the first embodiment or the previous configuration are used for the same parts and portions as those in the first embodiment or the previous configuration, and the description and illustration are omitted. There is.

(Second Embodiment)
FIG. 5 shows a front view in which a wiper device 111 including a wiper motor 110 according to a second embodiment of the present invention is partially cut away. As shown in this figure, the wiper motor 110 includes a gear housing 112 instead of the gear housing 32. The gear housing 112 includes a bottom portion 112A, a cylindrical portion 112B, and a flange portion 112C that are formed to have substantially the same diameter as the bottom portion 32A, the cylindrical portion 32B, and the flange portion 32C, while a frame portion 114 corresponding to the frame 72 is integrally formed. Has been. Further, a portion corresponding to the screw boss portion 74 is not formed on the bottom portion 112A.

  That is, in the wiper device 111, the pivot holders 78 and 80 are integrally formed on the gear housing 112 of the wiper motor 110. The wiper motor 110 constituting the wiper device 111 has a motor output shaft compared to the wiper motor 10 (see the imaginary line in FIG. 5) by the amount that passes through the frame 72 because the motor output shaft 36 protrudes toward the link mechanism 90. 36, the boss | hub part 40 is comprised short. Other configurations of the wiper motor 110 and the wiper device 111 are the same as the corresponding configurations of the wiper motor 10 and the wiper device 11.

  Therefore, the wiper motor 110 and the wiper device 111 according to the second embodiment can obtain the same effect by the same operation as the wiper motor 10 and the wiper device 11 according to the first embodiment.

  Further, in the wiper device 111 to which the wiper motor 110 is applied, since the frame portion 114 is integrated with the gear housing 112, the number of parts can be reduced and the cost can be reduced by reducing the processing cost. As a result, the thickness can be further reduced. Specifically, compared to the wiper motor 10 indicated by the imaginary line in FIG. 5, the crank arm 92 can be arranged more upward, and the module type wiper device 111 is thinned particularly in the center in the vehicle width direction. Is planned.

  For example, in a wiper motor having a speed reduction mechanism that transmits rotation between staggered shafts such as a worm speed reduction mechanism, the shape of the housing is complicated and it is difficult to form a frame integrally. However, the armature shaft 14 and the motor output In the wiper motor 110 in which the shaft 36 is disposed substantially in parallel (coaxial), the shape of the gear housing is particularly simplified, so that a configuration in which the frame portion 114 is integrated like the gear housing 112 is easily realized.

(Third embodiment)
FIG. 10 shows a differential reduction mechanism 142 constituting a wiper motor 140 according to the third embodiment of the present invention in a cross-sectional view perpendicular to the axis corresponding to FIG. As shown in this figure, the differential speed reduction mechanism 142 has a plurality of engagement protrusions 58 and engagement holes 62 arranged at unequal intervals in the circumferential direction to constitute a rotation take-out mechanism (Oldham mechanism) 144. In this respect, it differs from the differential reduction mechanism 38 having a rotation take-out mechanism 56 in which a plurality of engagement protrusions 58 and engagement holes 62 are arranged at equal intervals in the circumferential direction.

  Similar to the rotation extraction mechanism 56, the rotation extraction mechanism 144 includes eight engagement protrusions 58 and engagement holes 62. The eight sets of engagement protrusions 58 and engagement holes 62 include It is set so as to be able to absorb the difference between the movement locus Lp of the engagement protrusion 58 accompanying the rotation of the planetary gear 50 and the movement locus Lo of the engagement hole 62 accompanying the rotation of the motor output shaft 36. That is, the engagement projections 58 provided in the planetary gear 50 and the engagement holes 62 provided in the flange portion 60 have the circumferential arrangement patterns that are unequally aligned with each other, and correspond to each other. The pair of the engagement protrusion 58 and the engagement hole 62 that transmit rotation to the motor output shaft 36 (flange portion 60) is sequentially switched according to the revolution position and the rotation position of the planetary gear 50.

  In this embodiment, a part of the interval between the engagement protrusions 58 and the engagement holes 62 adjacent to each other in the circumferential direction is defined by an angle α0 that is 45 ° as in the differential reduction mechanism 38. In the rotation take-out mechanism 144, the other part of the interval between the engagement protrusion 58 and the engagement hole 62 adjacent in the circumferential direction is defined by angles α1 and α2 different from the angle α0.

  More specifically, in the rotation take-out mechanism 144 according to this embodiment, the angle α1 = 40 ° and the angle α2 = 50 °. In this embodiment, among the intervals between the engagement protrusions 58 and the engagement holes 62 adjacent in the circumferential direction, the portion of the angle α1 and the portion of the angle α2 are disposed at two positions that are axially symmetric. Therefore, the remaining four locations are portions where the spacing between the engagement protrusion 58 and the engagement hole 62 is an angle α0. And in this embodiment, the part of angle (alpha) 1 and the part of angle (alpha) 2 are arrange | positioned adjacent to the circumferential direction.

  In this embodiment, the number of teeth of the external teeth 50A of the planetary gear 50 is 50, whereas the number of teeth of the internal teeth 48A of the ring gear 48 is 49. Therefore, in the rotation take-out mechanism 144, the number of teeth of the internal teeth 48A located within the range of the minimum angle α1 is (40 ° × 49/360 °) ≈5.4 and is located within the range of the maximum angle α2. The number of teeth of the inner teeth 48A is approximately 6.8. Thereby, in the rotation taking-out mechanism 144, the number N1 of the inner teeth 48A that mesh with the external teeth 50A at the portion (range) of the minimum angle α1, and the number of teeth N2 of the inner teeth 48A that mesh with the external teeth 50A at the portion of the angle α2. Difference ΔN (= N2−N1) is set to be one or more. The other configuration of the wiper motor 140 is the same as the corresponding configuration of the wiper motor 10 or the wiper motor 110.

  Therefore, the wiper motor 140 according to the third embodiment can basically obtain the same effect by the same operation as the wiper motors 10 and 110 according to the first or second embodiment.

  Further, in the wiper motor 140, since the engagement protrusions 58 and the engagement holes 62 constituting the rotation take-out mechanism 144 are arranged at unequal intervals, the motor output shaft 36 is smoothly rotated. Supplementing this point, the rotation of the planetary gear 50 is selectively extracted from the movement of the armature shaft 14 of the planetary gear 50 around the axis AL and the rotation accompanied by the rotation about the eccentric axis EL. In the configuration of transmitting as rotation, the force (transmission torque) acting on one engagement protrusion 58 and engagement hole 62 changes in a sine wave shape according to the rotation angle of the motor output shaft 36, so that the entire rotation take-out mechanism 144 The torque transmission rate as follows is accompanied by fluctuations corresponding to the number of the engagement protrusions 58 and the engagement holes 62.

  Here, in the wiper motor 140, as described above, the engagement protrusions 58 and the engagement holes 62 constituting the rotation take-out mechanism 144 are arranged at unequal intervals. For this reason, the period in which the pair of the engagement protrusion 58 and the engagement hole 62 engaged with each other in accordance with the rotation is sequentially switched becomes unequal, and resonance due to the collision between the engagement protrusion 58 and the hole wall of the engagement hole 62 occurs. Is unlikely to occur. That is, since the collision cycle between the engagement protrusion 58 and the hole wall of the engagement hole 62 changes according to the angle α between the engagement protrusions 58 adjacent in the circumferential direction and between the engagement holes 62, the planetary gear 50 and the flange portion Even if vibration is generated in 60, it is resonated and the vibration is suppressed from continuing for a long time.

  In particular, in the wiper motor 140, the portion of the minimum angle α1 and the portion of the maximum angle α2 are different in the number of teeth of the inner teeth 48A meshing with the external teeth 50A by one or more, and the portion of the minimum angle α1 and the portion of the maximum angle α2 Are arranged adjacent to each other in the circumferential direction. For this reason, in the wiper motor 140, the fluctuation curve of torque transmission from the planetary gear 50 to the motor output shaft 36 is engaged with the fluctuation wall (the two engagement protrusions 58 adjacent in the circumferential direction to the hole wall of the corresponding engagement hole 62. Regions (periods) that are greatly different from each other are continuously generated. For this reason, in the wiper motor 140, even if vibration occurs in the planetary gear 50 or the flange portion 60, it is prevented or effectively suppressed that the vibration resonates and the vibration continues for a long time.

  Thus, in the wiper motor 140 according to the third embodiment, smooth rotation characteristics of the motor output shaft 36 can be obtained as compared with the first and second embodiments. Further, in the wiper motor 140, it is possible to reduce rotational vibration (output torque vibration), operation noise, and vibration of the motor output shaft 36.

  In the third embodiment, an example in which a part between the engagement protrusions 58 adjacent to each other in the circumferential direction and a part between the engagement holes 62 is unequal is shown. However, the present invention is not limited to this. For example, all of the intervals between the engagement protrusions 58 adjacent to each other in the circumferential direction and between the engagement holes 62 may be set at unequal intervals. Further, in the configuration in which a part between the engagement protrusions 58 adjacent to each other in the circumferential direction and the part between the engagement holes 62 are unequal, the angle is limited to three types of α1, α2, and α3. No, two or more types may be used.

(Fourth embodiment)
Although not shown, the wiper motor according to the fourth embodiment has seven engaging projections 58 and seven engaging holes 62. That is, in this wiper motor, the number of engaging protrusions 58 as engaging portions and the number of engaging holes 62 as engaged portions are odd numbers. In this embodiment, the engagement protrusions 58 and the engagement holes 62 are arranged at equal intervals in the circumferential direction of the planetary gear 50 and the flange portion 60.

  Further, the motor main body 10A constituting the wiper motor is a DC motor having two poles and 12 slots (the number of windings 18B of the core 18A is twelve). Therefore, in this wiper motor, the number of engagement parts (seven as the number of the engagement protrusions 58 and the engagement holes 62) of the rotation take-out mechanism 56 constituting the differential reduction mechanism 38 constitutes the motor main body 10A. The number of slots (12) formed in the core 18A of the armature 18 is set to have no common divisor other than 1 (1 is the greatest common divisor). Other configurations of the wiper motor are the same as the corresponding configurations of the wiper motor 10 or the wiper motor 110.

  Therefore, even with the wiper motor according to the fourth embodiment, basically the same effect can be obtained by the same operation as the wiper motors 10 and 110 according to the first or second embodiment.

  Moreover, in this wiper motor, since the number of the engagement protrusions 58 and the engagement holes 62 is an odd number, the torque fluctuation of the motor output shaft 36 can be suppressed as compared with a configuration in which these numbers are an even number. FIG. 11 is a diagram (experimental result) showing the torque fluctuation width (both amplitudes) of the motor output shaft 36 for each number of the engagement protrusions 58 and the engagement holes 62. From this figure, when the number of the engagement protrusions 58 and the engagement holes 62 is an odd number, the torque fluctuation is smaller than when the number of engagement protrusions 58 and the number of the engagement holes 62 is an even number before and after that. It can be seen that the torque variation decreases as the number of the engagement holes 62 increases. In particular, when the number of the engagement protrusions 58 and the engagement holes 62 is an odd number of 7 or more, the torque fluctuation of the motor output shaft 36 can be suppressed smaller than that of an even number of 8 or more. Here, in the wiper motor, since the number of the engagement protrusions 58 and the engagement holes 62 is seven, the torque fluctuation of the motor output shaft 36 is suppressed as compared with the configuration in which these numbers are an even number as described above. can do.

  Further, in this wiper motor, the number of the engagement protrusions 58 and the engagement holes 62 (seven) and the number of slots of the motor main body 10A (12) do not have a common divisor other than 1, The motor output shaft 36 is smoothly rotated. This point will be supplemented with reference to FIGS. 12 (A) to 12 (C). In FIG. 12A, the torque fluctuation due to the electrical factor in the two-pole 12-slot motor main body 10A as described above is shown in a diagram (measured waveform). From this figure, it can be seen that in the motor main body 10A, torque fluctuations of 12 cycles per rotation occur. In FIG. 12B, the change (fluctuation) of the torque transmission rate in the rotation take-out mechanism 56 (differential reduction mechanism 38) having seven engaging parts that are sequentially switched as described above is shown in a diagram (measured waveform). It is shown. From this figure, it is understood that in the rotation take-out mechanism 56, a change in torque transmission rate of 14 cycles per rotation occurs. 12C shows an output shaft obtained by multiplying the torque fluctuation due to the electrical factor shown in FIG. 12A and the change in torque transmission rate due to the mechanical factor shown in FIG. 12B in the same phase. The torque fluctuations of 36 (entire wiper motor) are shown in a diagram. From this figure, it can be seen that in this wiper motor, it is suppressed that the torque fluctuation due to the electrical factor and the change in the torque transmission rate due to the mechanical factor are amplified in synchronization with each other.

  As described above, in the wiper motor according to the fourth embodiment, smooth rotation characteristics of the motor output shaft 36 can be obtained as compared with the first and second embodiments. Further, in the wiper motor 140, it is possible to reduce rotational vibration (output torque vibration), operation noise, and vibration of the motor output shaft 36.

  In the fourth embodiment, the example in which the seven engagement protrusions 58 and the engagement holes 62 are arranged at equal intervals in the circumferential direction is shown. However, the present invention is not limited to this, and for example, the third As in the embodiment, at least a part of the seven engaging protrusions 58 and the engaging holes 62 may be arranged at unequal intervals. In this case, for example, at least a part of the engagement protrusions 58 and the engagement holes 62 are arranged at unequal intervals so that torque fluctuations at 0 ° (360 °) and 180 ° in FIG. It is desirable to do.

  In the fourth embodiment, the number of the engagement protrusions 58 and the engagement holes 62 is an odd number, and the number of the engagement protrusions 58 and the engagement holes 62 and the number of slots of the motor body 10A are other than one. Although a preferred example having no common divisor has been shown, the present invention is not limited to this. Therefore, for example, in the configuration in which the number of the engagement protrusions 58 and the engagement holes 62 is an odd number, the number of the engagement holes 62 and the number of slots of the motor body 10A have a common divisor other than 1 (for example, The number of the engagement protrusions 58 and the engagement holes 62 may be nine, etc. with respect to the number of slots 12, and for example, the number of the engagement protrusions 58 and the engagement holes 62 and the number of slots of the motor main body 10A are one. In the configuration having no other common divisor, the number of the engagement protrusions 58 and the engagement holes 62 is an even number (for example, the number of the engagement protrusions 58 and the engagement holes 62 is 12 for the number of slots 3). Etc.).

(Fifth embodiment)
FIG. 13 is a schematic axial cross-sectional view of the main part of a wiper motor 150 according to a fifth embodiment of the present invention. As shown in this figure, the wiper motor 150 is the wiper motor 10 according to the first to fourth embodiments in that the counterweight 55 is arranged in a predetermined manner with respect to the teeth 18C as tooth portions constituting the core 18A. , 110, 140, etc.

  The teeth 18C extend radially from the axis of the core 18A and define the circumferential end of the slot 18D. The teeth 18C hold the winding 18B. In the wiper motor 150, the maximum eccentric portion 55A farthest from the axis of the motor output shaft 36 of the counterweight 55 is arranged offset in the circumferential direction by a predetermined angle θ1 with respect to the circumferential center line CLt of the specific tooth 18C. ing. In this embodiment, from the relationship (experimental result) with the torque fluctuation range (both amplitudes) due to the revolution of the planetary gear 50 with respect to the angle θ shown in FIG. 14, θ1≈15 ° at which the torque fluctuation range is minimized is set. Yes.

  In this embodiment, the motor body 10A is a DC motor having two poles and 12 slots (the number of windings 18B of the core 18A is twelve), and the position of the maximum eccentric portion 55A where θ1 = 15 ° is A configuration in which the circumferential position substantially coincides with an intermediate portion (the circumferential center line CLs of the slot 18D formed by these teeth) 18C and the teeth 18C adjacent to the circumferential direction in the circumferential direction of the teeth 18C, which is an offset reference. Has been. Other configurations of the wiper motor 150 are the same as the corresponding configurations of the wiper motors 10, 110, 140, and the like according to the first to fourth embodiments.

  Therefore, even with the wiper motor according to the fifth embodiment, basically the same effect can be obtained by the same operation as the wiper motors 10, 110, 140, etc. according to the first to fourth embodiments.

  In the wiper motor 150, the maximum eccentric portion 55A of the counterweight 55 has a minimum (minimum) torque fluctuation of the motor output shaft 36 with respect to the circumferential center line CLt of the specific tooth 18C as shown in FIG. They are arranged offset in the circumferential direction by a predetermined angle θ1≈15 °. For this reason, in the wiper motor 150, the motor output shaft 36 is smoothly rotated.

  As described above, in the wiper motor 150 according to the fifth embodiment, smooth rotation characteristics of the motor output shaft 36 can be obtained as compared with the first to fourth embodiments. Further, the wiper motor 150 can reduce rotational shake (output torque shake), operating noise, and vibration of the motor output shaft 36.

  In each of the above-described embodiments, an example in which a tooth shape of an involute curve is used as the inner teeth 48A of the ring gear 48 and the outer teeth 50A of the planetary gear 50 and the difference in the number of teeth between the two gears is 1 is shown. For example, as shown in FIG. 6 (A), the teeth of both gears are formed by a toothed inner tooth 48B formed using an involute curve, a ring gear 48 having an outer tooth 50B, and a planetary gear 50. A differential reduction mechanism 38 having a number difference of 3 may be configured. As shown in FIG. 6B, a ring gear 48 having tooth-shaped inner teeth 48C and outer teeth 50C formed using a cycloid curve. Alternatively, the planetary gear 50 may constitute the differential reduction mechanism 38 in which the difference in the number of teeth of both gears is 1. Note that the difference (ratio) between the outer diameter of the engagement protrusion 58 and the inner diameter of the engagement hole 62 is set in accordance with the difference between these tooth forms (tooth depth, that is, the eccentric amount ax).

  Further, in each of the above-described embodiments, the example in which the rotational position detection mechanism 64 includes the sensor magnet 66 including the ring magnets 66A to 66C over the entire circumference of the flange portion 60 has been described, but the present invention is not limited to this. For example, as shown in FIGS. 7A and 7B, the rotational position detection mechanism 64 may be configured using a sensor magnet 120 provided in a part of the flange portion 60 in the circumferential direction. good. FIG. 7 shows an example in which the sensor magnet 120 includes an inner ring magnet 120A, an intermediate ring magnet 120B, an outer ring magnet 120C, and three Hall elements 68A to 68C. The sensor magnet 120 may be composed of only one arc-shaped magnet coaxial with the flange portion 60, and the Hall elements 68A and the like may be provided according to the number of positions to be detected.

  Further, for example, as shown in FIGS. 8A and 8B, a contact-type rotational position detection mechanism 130 may be provided instead of the non-contact-type rotational position detection mechanism 64. The rotational position detection mechanism 130 is arranged in parallel in the radial direction on the movement locus of the substrate 133 on which the thin film-like movable conductive plate 132 having a predetermined conductive pattern shape is formed and the movable conductive plate 132 accompanying the rotation of the flange portion 60. A plurality of (three in this modified example) contact plates 134 arranged as described above are configured as main parts. The movable conductive plate 132 has an annular portion 132A in contact with two adjacent contact plates 134, and a portion in the circumferential direction of a region in which the contact plate 134 on the inner peripheral side of the annular portion 132A contacts is cut away. It has a notch 132B and an overhang 132C that protrudes from a part of the annular portion 132A in the circumferential direction to a region where the outer peripheral contact plate 134 contacts. Although a detailed description is omitted, the rotational position detection mechanism 130 detects the rotational position of the motor output shaft 36 based on the contact (conduction) state between the three contact plates 134 and the movable conductive plate 132. Yes.

  Further, in each of the above-described embodiments, as schematically illustrated in FIG. 2, an example in which the revolution about the axis AL of the armature shaft 14 is input to the planetary gear 50 is shown, but the present invention is not limited to this, For example, as schematically shown in FIG. 9, the ring gear 48 may be configured to input revolutions around the axis AL of the armature shaft 14.

  Furthermore, in the above-described embodiment, the example in which the rotation take-out mechanism 56 is configured by the engagement protrusion 58 provided in the planetary gear 50 and the engagement hole 62 provided in the flange portion 60 is shown. The present invention is not limited to this, and the planetary gear 50 may be provided with the engagement hole 62 and the flange portion 60 with the engagement protrusion 58. Further, instead of the engagement hole 62 penetrating the planetary gear 50 or the flange portion 60, a concave portion into which the engagement protrusion 58 enters may be provided, and a convex portion (engagement portion) protruding from both the planetary gear 50 and the flange portion 60 may be provided. And the engaged portion) may constitute the rotation take-out mechanism 56. Furthermore, it goes without saying that the shapes of the engagement protrusions 58 and the engagement holes 62 viewed from the axial direction of the armature shaft 14 are not limited to circular shapes.

  In the above-described embodiment, the example in which the flange portion 60 and the motor output shaft 36 constituting the rotation take-out mechanism 56 rotate integrally has been shown. However, the present invention is not limited to this example. A reduction gear or the like may be provided between the motor output shaft 36 and the motor output shaft 36. That is, it is sufficient if the flange portion 60 and the motor output shaft 36 are configured to rotate in synchronization.

DESCRIPTION OF SYMBOLS 10 ... Wiper motor, 10A ... Motor main-body part (motor main body), 11 ... Wiper apparatus 14 ... Armature shaft (rotary axis), 36 ... Motor output shaft (output shaft), 48 ... Ring gear, 48A ... inner teeth, 50 ... planetary gear (planetary gear), 50A ... outer teeth, 55 ... counter weight (balance weight), 56 ... automatic rotation take-out mechanism (rotation conversion mechanism) , 58... Engaging protrusion (engaging portion), 60... Flange portion (rotating member), 62... Engaging hole (engaged portion), 64. .... Sensor magnet (detected part), 68 ... Magnetic sensor (detecting part), 78 ... 80 ... Pivot holder (pivot holder part), 82 ... First wiper arm (wiper arm), 84 ... First pivot shaft 86 .. second wiper arm (wiper arm), 88 ... second pivot shaft, 90 ... link mechanism, 110.140.150 ... wiper motor, 111 ... wiper device, 112 ... gear housing ( At least a part of the wiper motor housing), 120... Sensor magnet (detected portion), 130... Rotational position detection mechanism, 132... Movable conductive plate (detected portion), 134. Detection unit), 144... Rotation extraction mechanism (rotation conversion mechanism)

Claims (12)

A ring gear having internal teeth;
A planetary gear having outer teeth meshed with the inner teeth of the ring gear in a part in the circumferential direction, and a diameter of the pitch circle being larger than a radius of the pitch circle of the ring gear;
A motor main body having a rotating shaft that is coaxially arranged with one of the ring gear and the planetary gear and is eccentrically connected to the other of the ring gear and the planetary gear;
An output shaft supported so as to be capable of rotating about an axis parallel to the rotation axis of the motor body;
A rotation conversion mechanism for converting the other rotation of the ring gear and the planetary gear to the rotation of the output shaft;
Wiper motor with   The wiper motor according to claim 1, wherein a diameter of a tip circle of the planetary gear is larger than a diameter of a tip circle of the ring gear.   The wiper motor according to claim 1 or 2, wherein the rotation shaft of the motor body and the output shaft are arranged coaxially. The rotation conversion mechanism is
A plurality of engagement portions provided on the other of the ring gear and the planetary gear so that at least a part thereof is unequal in the circumferential direction;
The output shaft or a rotating member that rotates in synchronization with the output shaft is provided with a plurality so that at least a part thereof is unequally spaced in the circumferential direction, and the engagement portions are engaged in the circumferential direction, An engaged portion that can be in a non-engaged state;
The wiper motor according to any one of claims 1 to 3, wherein the wiper motor is configured to include a motor. The rotation conversion mechanism is
A plurality of engagement portions provided at equal intervals in the circumferential direction on the other of the ring gear and the planetary gear;
A plurality of rotating members that rotate in synchronization with the output shaft or the output shaft are provided at equal intervals in the circumferential direction, and each of the engagement portions can take a state in which the engagement portion is engaged in the circumferential direction and a state in which the engagement portion is not engaged. An engaging portion;
The wiper motor according to any one of claims 1 to 3, wherein the wiper motor is configured to include a motor.   The wiper motor according to claim 4 or 5, wherein the number of the engaging portions and the engaged portions is an odd number.   The number of the engaging portions and the engaged portions is any number that does not have a common divisor other than 1 with respect to the number of slots constituting the motor body. The wiper motor described.   The rotation position detection mechanism for detecting the rotation position of the said output shaft which has a detection part or a detected part provided in the rotation member that rotates in synchronization with the output shaft or the output shaft. The wiper motor according to any one of claims 1 to 7.   A balance weight disposed between the motor main body on the rotating shaft and the other of the ring gear and the planetary gear, the balance weight for canceling an unbalance associated with the other revolution of the ring gear and the planetary gear on the rotating shaft; The wiper motor according to any one of claims 1 to 8.   10. The wiper motor according to claim 9, wherein a maximum eccentric position of the balance weight with respect to the axis of the rotation shaft is offset in a circumferential direction with respect to a circumferential center line of a plurality of tooth portions constituting a slot of the motor body. A pivot shaft for transmitting driving force to the wiper arm;
The wiper motor according to any one of claims 1 to 10, wherein the output shaft is disposed in parallel with the pivot shaft.
A link mechanism that is disposed on the same side in the respective axial directions with respect to the wiper motor and the pivot shaft, and converts the rotation of the output shaft into the swing of the pivot shaft;
Wiper device with   The wiper device according to claim 11, wherein a pivot holder portion that rotatably supports the pivot shaft and at least a part of a housing of the wiper motor are integrally formed.

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