JP6442031B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

  2. Description of the Related Art Conventionally, as a wiper motor for an automobile, a three-brush electric motor that can switch the rotation speed is sometimes used. In this type of electric motor, a plurality of magnets are arranged at intervals in the circumferential direction on the inner peripheral surface of a bottomed cylindrical yoke, and an armature is rotatably arranged inside these magnets.

The armature includes an armature core that is externally fixed to the rotary shaft, an armature coil that is wound around the armature core, and a commutator that is externally fixed to the rotary shaft so as to be adjacent to the armature core.
The commutator is arranged in the circumferential direction in a state where a plurality of segments are insulated from each other, and an end portion of an armature coil is connected to each of the segments. A plurality of brushes are slidably contacted with each segment at intervals in the circumferential direction, and power is supplied to each armature coil through these brushes.

  Each brush is composed of a low-speed brush and a high-speed brush, and a common brush used in common with these brushes, and each brush is held by a brush holder stay via a brush holder. The low speed brush and the common brush are arranged at positions 180 degrees apart in electrical angle (mechanical angle x number of pole pairs), and the high speed brush is arranged at a predetermined angle in the circumferential direction with respect to the low speed brush. Is done. The speed of the electric motor can be switched by selectively switching the energization to the low speed brush and the high speed brush.

  Here, Patent Document 1 below discloses a so-called hammer brush configuration in which a brush holder is formed in a leaf spring shape in an electric motor having a 2-pole-3 brush structure with two magnetic poles and three brushes. ing. Specifically, the hammer brush disclosed in Patent Literature 1 includes a U-shaped brush holder stay having a main wall portion and a pair of side wall portions extending from both ends of the main wall portion, and extends along the circumferential direction. And a plurality of brush holders biased toward the inner side in the radial direction, and a brush fixed to protrude toward the inner side in the radial direction at the tip of each brush holder.

  Each brush holder has a base end portion supported on the main wall portion of the brush holder stay at an interval in the circumferential direction, and is inclined toward the inner side in the radial direction toward the distal end portion. In the electric motor disclosed in Patent Document 1, the low speed brush and the common brush are slidably contacted with the commutator from a position 180 degrees apart from the mechanical angle, and the high speed brush is slid onto the commutator from a position separated from the low speed brush by a predetermined angle. It touches.

  When the above-described hammer brush is assembled to the armature, first, each brush holder is pressed in a direction against the urging force by a jig or the like to widen the interval between the brushes (opening step). Next, in a state where the opening of the brush holder stay (the gap between the side wall portions) and the commutator are opposed to each other in the radial direction, the brush holder stay is approached in the radial direction toward the commutator (assembly process). Thereby, a commutator is inserted inside a brush holder stay, and a commutator is arrange | positioned between each brush. Thereafter, by releasing the pressure of the brush holder, each brush holder is restored, and the brush of each brush holder is held in contact with the segment.

Japanese Patent No. 4335462

  Recently, in order to reduce the size and increase the performance of the wiper motor, the number of magnetic poles may be increased to 4 poles (2 pole pairs) (4-pole-3 brush structure).

  Here, when the above-described hammer brush is employed in the 4-pole-3 brush structure, it is difficult to assemble the brush holder stay and the armature. That is, in the case of the 2-pole-3 brush structure as in Patent Document 1, the mechanical angle of the low-speed brush and the common brush is set to 180 ° as described above, and therefore, for example, along the assembly direction of the brush holder stay The brush for high speed can be brought into contact with the commutator from the front side (main wall side), and the brush for low speed and the common brush can be brought into contact with the commutator from the direction orthogonal to the assembly direction (side wall side).

On the other hand, in the case of the 4-pole-3 brush structure, the low-speed brush and the common brush are arranged at a mechanical angle of 90 degrees, and the high-speed brush is predetermined in the circumferential direction with respect to the low-speed brush. It is necessary to arrange them at an angular distance. Therefore, in order to assemble the brush holder stay to the commutator by the same method as in Patent Document 1 described above, for example, a low speed brush and a common brush are arranged on the front side in the assembling direction, while the rear side (brush in the assembling direction) It is necessary to wrap around the brush for high speed from the holder stay opening side).
Therefore, the assembling property is poor and it is difficult to arrange the brush at a desired position with high accuracy.

  Therefore, the present invention has been made in view of the above-described problems, and even when a multipolarization of four or more poles is achieved, an electric motor that can perform a desired brush arrangement without reducing the assembling property. A motor is provided.

  In order to solve the above-described problems, an electric motor according to the present invention is attached to a yoke having a cylindrical portion, a magnet having four or more magnetic poles disposed on an inner peripheral surface of the cylindrical portion, and a rotating shaft. In addition, an armature that is rotatable inside the yoke, a commutator that is attached to the rotating shaft and has a plurality of segments, a plurality of brushes that are in sliding contact with the segments and that supplies power, and the brushes are held separately. In the electric motor comprising the brush holder and the brush holder stay that supports the brush holder, the brush holder stay has an opening through which the commutator can be inserted along the axial direction of the rotating shaft, Among the segments, the segments having the same potential are short-circuited with a connection line, and the brush is a low-speed brush and a high-speed brush, and A high-speed brush and a common brush used in common with the high-speed brush, and the low-speed brush and the common brush are arranged at an electrical angle of 180 ° in the circumferential direction, and the high-speed brush Is disposed in a second region that is radially opposed to the first region between the low-speed brush and the common brush along the circumferential direction, with the rotating shaft interposed therebetween, and is electrically connected to the brush. While having a plurality of terminals to be connected, a connector part for connecting to the outside is formed integrally with the brush holder stay via a bridge part, and the distance between the high speed brush and the connector part is Shorter than the distance between the low speed brush and the common brush and the connector portion, the low speed brush and the high speed brush in the brush holder stay are not connected to the low speed brush. An anti-noise element connected to the brush for operation is disposed, and an anti-noise element connected to the brush for high speed is disposed on the bridge portion.

In the electric motor according to the present invention, the noise prevention element may be arranged so that a longitudinal direction of the noise prevention element is along an in-plane direction of the brush holder stay and the bridge portion.
In the electric motor according to the present invention, the brush holder stay and the bridge portion may be formed on the same surface.
In the electric motor according to the present invention, the connector portion includes a connector base portion extending on the same plane as the brush holder stay and the bridge portion, and a partition wall portion erected from the connector base portion. May be.

In the electric motor according to the present invention, the high-speed brush may have a narrower circumferential width than the low-speed brush and the common brush.
According to this configuration, since the high-speed brush has a narrower circumferential width than other brushes, for example, the low-speed brush and the high-speed brush contact each other across two adjacent segments in the circumferential direction. It can suppress that it is in the state (short circuit state) which is doing. Thereby, rectification | straightening property can be improved.

In the electric motor according to the present invention, the worm coupled to the rotating shaft and the output shaft are fixed, and meshed with the worm to reduce the rotation of the rotating shaft and output from the output shaft. A speed reduction mechanism having a worm wheel; and a gear housing that houses the speed reduction mechanism and the brush holder stay, wherein the brush holder stay is formed with a positioning portion that performs axial positioning with respect to the gear housing. It may be.
According to this configuration, since the brush holder stay and the gear housing can be positioned in the axial direction via the positioning portion, the armature is assembled to the brush holder stay as described above after the brush holder stay is assembled to the gear housing. Thus, the armature can be positioned in the axial direction with respect to the gear housing. Thereby, the further improvement of assembly property can be aimed at.

  In the electric motor according to the present invention, the connector portion is provided with a contact plate partially embedded in the connector portion, and the contact plate is in sliding contact with a relay plate provided on the worm wheel. It may be.

  According to the present invention, a desired brush arrangement can be performed without degrading the assemblability even when multipolarization of four or more poles is achieved.

It is a perspective view of the wiper motor in an embodiment. It is sectional drawing which follows the AA line of FIG. It is a disassembled perspective view of a wiper motor. It is the top view which looked at the holder unit from the other end side along a rotating shaft direction. It is a side view of a holder unit. It is a disassembled perspective view of a yoke, a gear housing, and a holder unit. It is sectional drawing which follows the BB line of FIG. It is the top view which looked at the holder unit which shows the other structure of embodiment from the other end side along a rotating shaft direction. It is a perspective view of a wiper motor showing other composition of an embodiment. It is a perspective view of a wiper motor showing other composition of an embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Wiper motor]
FIG. 1 is a perspective view of a wiper motor 1 in the embodiment, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
As shown in FIGS. 1 and 2, the wiper motor 1 of the present embodiment drives a front wiper (not shown) that wipes a front window of a vehicle (not shown), for example. Specifically, the wiper motor 1 includes an electric motor 2, a speed reduction mechanism 4 (see FIG. 2) connected to a rotating shaft 3 (see FIG. 2) of the electric motor 2, and a part of the speed reduction mechanism 4 and the electric motor 2. And a gear housing 5 that accommodates the electric motor 2. The driving force of the electric motor 2 is decelerated by the speed reduction mechanism 4 and then transmitted to the front wiper via an output shaft 95 described later. In the following description, the axial direction of the rotating shaft 3 may be referred to as a rotating shaft direction O1, and the axial direction of the output shaft 95 may be referred to as an output shaft direction O2.

<Electric motor>
FIG. 3 is an exploded perspective view of the wiper motor 1.
As shown in FIGS. 2 and 3, the electric motor 2 includes a bottomed cylindrical yoke 7 and an armature 6 rotatably provided in the yoke 7.

In the yoke 7, a plurality of (for example, four) magnets 12 are arranged on the inner peripheral surface of the cylindrical portion 11 along the circumferential direction around the rotation shaft 3.
On the other hand, in the bottom wall (end portion) 15 of the yoke 7, a boss portion 13 that protrudes outward in the rotational axis direction O <b> 1 is formed in the center in the radial direction. A bearing 14 (see FIG. 2) for pivotally supporting one end (the armature 6 side along the rotation axis direction O1) is provided. A plurality of recesses 16 that are recessed toward the one end side in the rotation axis direction O1 are formed in the opening edge of the cylindrical portion 11 at intervals in the circumferential direction.

The armature 6 has an armature core 21 fitted and fixed to the rotary shaft 3, an armature coil 22 wound around the armature core 21, and the other end side (rotational axis direction) with respect to the armature core 21 along the rotary axis direction O1. And a commutator 23 arranged on the side opposite to the armature 6 along O.
The armature core 21 is a laminate of magnetic material punched by pressing or the like in the rotational axis direction O1, and a plurality of teeth 21a around which the armature coil 22 is wound are formed radially.

  The commutator 23 is externally fitted and fixed to the rotary shaft 3, and a plurality of segments 24 made of a conductive material are attached to the outer peripheral surface thereof. The segments 24 are made of plate-like metal pieces that are long in the rotation axis direction O1, and are fixed in parallel at equal intervals along the circumferential direction in a state of being insulated from each other.

In each segment 24, a riser 25 is integrally formed at one end portion along the rotation axis direction O1 so as to be folded back outward in the radial direction. A terminal portion of the armature coil 22 is wound around the riser 25 and fixed by fusing or the like. Thereby, the segment 24 and the armature coil 22 corresponding to this are electrically connected.
A connection line (not shown) is wound around the risers 25 corresponding to the segments 24 having the same potential, and the connection lines are fixed to the riser 25 by fusing. The connection line is for short-circuiting the segments 24 having the same potential, and is routed between the commutator 23 and the armature core 21.

  As shown in FIG. 3, the brush 31 is in sliding contact with the segment 24 of the commutator 23. The brush 31 is in sliding contact with the segment 24 so as to supply current to the armature coil 22 via the segment 24. The brush 31 is held by the holder unit 32 via a brush holder 41 described later.

<Holder unit>
4 is a plan view of the holder unit 32 as viewed from the other end side along the rotation axis direction O1, and FIG. 5 is a side view of the holder unit 32. As shown in FIG.
As shown in FIGS. 3 to 5, the holder unit 32 is disposed adjacent to the brush holder stay 33 in a radial direction with respect to the brush holder stay 33 disposed at a position overlapping the electric motor 2 in the rotation axis direction O <b> 1. The connector portion 34 and a bridge portion 35 that bridges the brush holder stay 33 and the connector portion 34 in the radial direction are integrally formed of a resin material or the like.

  The brush holder stay 33 includes an annular holder base portion 36, and a positioning portion 37 projects from the outer peripheral edge of the holder base portion 36 toward one end side in the rotation axis direction O1. The positioning portion 37 extends to a position close to the armature core 21, and a tip portion thereof is bent outward in the radial direction. And the front-end | tip part of the positioning part 37 is engaged with the frame part 61 mentioned later, and the positioning along the rotating shaft direction O1 of the holder unit 32 with respect to the frame part 61 is performed by this. The inner diameter of the holder base portion 36 is set to a size that allows the commutator 23 to be inserted, and the commutator 23 is inserted inside the holder base portion 36.

  In the holder base portion 36, brush holders 41 are fixed at three locations in the circumferential direction on a surface (hereinafter simply referred to as a mounting surface) located on the other end side along the rotation axis direction O1. The brush holder 41 is made of a conductive material, has a leaf spring shape extending along the rotation axis direction O1, and is urged toward the inner side in the radial direction. Specifically, the brush holder 41 has a base end portion fixed to the holder base portion 36 via a claw portion (not shown), and is inclined inward in the radial direction toward the distal end portion. And the brush 31 is each provided in the front-end | tip part of the brush holder 41 so that it may protrude toward the inner side of radial direction.

  Each brush 31 has a triangular shape in a side view in which the width in the rotation axis direction O1 is gradually tapered toward the inner side in the radial direction, and the base end portion (the outer end portion in the radial direction) is fitted to the distal end portion of the brush holder 41. The tip portion (the inner end portion in the radial direction) is in sliding contact with the segment 24 of the commutator 23. As a result, power from a battery (not shown) can be supplied to the commutator 23 via the brush 31.

Here, the brush 31 is connected to the anode side, the low speed brush 31a and the high speed brush 31b, and connected to the cathode side, and is commonly used for the low speed brush 31a and the high speed brush 31b. And.
The low speed brush 31a is a brush 31 that is used when the front wiper is driven at a low speed by applying a voltage between the low speed brush 31a and the common brush 31c. The high speed brush 31b is a brush 31 that is used when the front wiper is driven at a high speed by applying a voltage between the high speed brush 31b and the common brush 31c. The tip of the high speed brush 31b has a smaller width in the circumferential direction than the other brushes 31a and 31c (D1> D2 in FIG. 4).

  As shown in FIG. 4, the low speed brush 31a and the common brush 31c have an electrical angle of 180 °, that is, a mechanical angle (the narrower one of the central angles formed by the brushes 31a and 31c with the rotation shaft 3 as the center). At an angle of 90 ° (reduced angle side)). On the other hand, the high speed brush 31b is spaced apart by a predetermined angle in the circumferential direction with respect to the low speed brush 31a on the wider angle (dominant angle) side of the central angles formed by the brushes 31a and 31c with the rotation shaft 3 as the center. Are arranged.

  In this case, in the holder base portion 36, the low speed brush 31a and the common brush 31c are disposed on the opposite side of the connector portion 34 with respect to the commutator 23 (rotation axis direction O1), and the high speed brush 31b is disposed in the commutator 23 (rotation axis direction). O1) is arranged on the connector 34 side. Therefore, the distance between the high-speed brush 31b and the connector portion 34 is shorter than the distance between the low-speed brush 31a and the common brush 31c and the connector portion 34.

In the example of FIG. 4, the high-speed brush 31b has a line-symmetric region (first region) that is opposed in the radial direction to the subordinate angle region (first region) E1 between the low-speed brush 31a and the common brush 31c in the circumferential direction. (2 areas) are arranged in E2.
According to this configuration, the high-speed brush 31a, the common brush 31c, and the high-speed brush 31b are arranged in regions that are opposed to each other in the radial direction (the subtractive angle region E1 and the line symmetry region E2). Compared with the configuration in which 31b is disposed in the subtractive angle region E1, the contact pressures of the brushes 31a to 31c with respect to the segment 24 can be evenly applied in the circumferential direction. Thereby, the axial deviation of the rotating shaft 3 can be suppressed and the motor operating noise can be reduced.

One end portions of jumper wires 42 and 43 are connected to the brush holder 41 corresponding to the low speed brush 31a and the high speed brush 31b. The other ends of the jumper wires 42 and 43 are connected to a power terminal 55 described later.
Further, a circuit breaker 44 is connected to the brush holder 41 corresponding to the common brush 31c, and one end of a jumper wire 45 is connected to the circuit breaker 44. The other end of the jumper wire 45 is connected to one contact plate 56 described later. The circuit breaker 44 is fixed to a portion located between the common brush 31c and the high speed brush 31b on the mounting surface of the holder base portion 36.

  The bridge portion 35 has a plate shape with the rotation axis direction O1 as the thickness direction, and extends from a part in the circumferential direction of the holder base portion 36 toward the outside in the radial direction. On the mounting surface of the bridge portion 35, the above-described jumper wires 42, 43, 45 are routed toward the connector portion 34.

  As shown in FIGS. 4 and 5, the connector portion 34 includes a connector base portion 51 extending on the same plane as the brush holder stay 33 and the bridge portion 35, and one end side from the connector base portion 51 along the rotational axis direction O <b> 1. A connector receiving portion 52 (see FIG. 5) erected toward the end, and a partition wall portion 53 erected from the connector base portion 51 toward the other end side along the rotation axis direction O1.

  A plurality of power terminals 55 for power supply and contact plates 56 for sensors are embedded in the connector base 51 by insert molding or the like. In the example of FIG. 4, two power terminals 55 and three contact plates 56 are embedded, and are arranged on the connector base portion 51 at intervals.

The power terminal 55 has a plate shape extending along the rotation axis direction O <b> 1 and penetrates the connector base portion 51. One end portion of the power terminal 55 projects into the connector receiving portion 52 to function as a connector terminal, and the other end portion is exposed on the mounting surface side of the connector base portion 51. Note that the above-described jumper wires 42 and 43 drawn from the low speed brush 31a and the high speed brush 31b are connected to the other end of each power terminal 55, respectively.
Similar to the power terminal 55, the contact plate 56 has a plate shape extending along the rotation axis direction O <b> 1 and penetrates the connector base portion 51. One end portion of the contact plate 56 projects into the connector receiving portion 52 to function as a connector terminal, and the other end portion is bent in a crank shape and extends toward the other end side along the rotation axis direction O1. doing. A contact portion 57 is formed at the other end of the contact plate 56 so as to be in sliding contact with a relay plate 103 described later. Of the contact plates 56, one of the contact plates 56 is connected to the above-described jumper wire 45 drawn from the common brush 31c on the mounting surface side.

<Gear housing>
FIG. 6 is an exploded perspective view of the yoke 7, the gear housing 5, and the holder unit 32.
As shown in FIGS. 2 and 6, the gear housing 5 includes an aluminum die-cast frame portion 61 formed in a bottomed cylindrical shape having a bottom wall portion 63 and a peripheral wall portion 64, and an opening portion 61 a of the frame portion 61. And a resin-made bottom plate 62 for closing.
The inside of the frame portion 61 is defined by a speed reduction mechanism storage portion 65 that stores the speed reduction mechanism 4 and a holder unit storage portion 66 that is connected to a part of the peripheral wall portion 64 and stores the above-described holder unit 32. ing.

  As shown in FIG. 6, the holder unit storage part 66 is provided with the bottomed cylindrical 1st receiving part 71 open | released toward the one end side along the rotating shaft direction O1 first. The first receiving portion 71 has an inner diameter that is large enough to receive the brush holder stay 33 described above, and the brush holder stay 33 and the commutator 23 are accommodated therein.

On the opening edge of the first receiving portion 71, a positioning recess 72 is formed in which the tip of the positioning portion 37 of the brush holder stay 33 described above is engaged. In addition, a positioning convex portion 74 that protrudes outward in the radial direction is formed in a portion of the first receiving portion 71 that is located on the other end side in the rotational axis direction O1 with respect to the positioning concave portion 72. The positioning convex portion 74 engages with the concave portion 16 of the yoke 7 described above to position the yoke 7 with respect to the gear housing 5.
An insertion hole 73 through which the rotary shaft 3 is inserted is formed at the bottom of the first receiving part 71, and the first receiving part 71 and the speed reduction mechanism housing part 65 communicate with each other through the insertion hole 73.

FIG. 7 is a sectional view taken along line BB in FIG.
As shown in FIGS. 6 and 7, the first receiving portion 71 is provided with a second receiving portion 75 that receives the connector portion 34 and the bridge portion 35 of the holder unit 32 so as to extend outward in the radial direction. The 2nd receiving part 75 is made into the square cylinder shape open | released in the rotating shaft direction O1, and is formed in the magnitude | size which can receive the connector part 34 and the bridge | bridging part 35 of the holder unit 32 mentioned above.
The second receiving portion 75 is formed with a communication hole 76 that communicates with the speed reduction mechanism storage portion 65, and the other end of the contact plate 56 faces the speed reduction mechanism storage portion 65 through the communication hole 76. Yes. Further, the second receiving part 75 communicates with the first receiving part 71 through the notch part 77. In the notch 77, an end of the bridge unit 35 of the holder unit 32 on the brush holder stay 33 side is accommodated.

As shown in FIG. 7, a through hole 81 penetrating the bottom wall portion 63 is formed in the center portion of the bottom wall portion 63 in the speed reduction mechanism housing portion 65. The through-hole 81 is inserted with an output shaft 95 to be described later, and a cylindrical sleeve 82 is erected on the inner peripheral edge of the through-hole 81 toward the outside in the output shaft direction O2. At the base end portion of the sleeve 82, a reduced diameter portion 84 whose inner diameter gradually decreases toward the distal end is formed. In addition, a cylindrical bush 83 made of oil-impregnated metal or the like is provided in the sleeve 82 over the entire sleeve 82 including the reduced diameter portion 84. In the sleeve 82, a gap is formed between the reduced diameter portion 84 and the bush 83.
Further, in the speed reduction mechanism housing portion 65, the peripheral wall portion 64 is formed with locking claws 85 protruding toward the outer side of the peripheral wall portion 64 at intervals in the circumferential direction of the peripheral wall portion 64.

  The bottom plate 62 is formed in a plate shape that follows the shape of the opening 61 a of the frame portion 61 and covers the opening 61 a of the frame portion 61. A plurality of attachment pieces 87 projecting toward the frame portion 61 are formed on the outer peripheral edge of the bottom plate 62 at intervals along the circumferential direction of the bottom plate 62. The mounting pieces 87 are formed with locking holes 87a for locking the locking claws 85 of the frame portion 61 described above.

<Deceleration mechanism>
As shown in FIGS. 2 and 7, the speed reduction mechanism 4 includes a worm 91 connected to the rotating shaft 3 of the electric motor 2 and a worm wheel 92 that meshes with the worm 91.
One end portion of the worm 91 along the rotation axis direction O1 is connected to the rotation shaft 3 in the speed reduction mechanism housing portion 65, and the other end portion thereof is rotatably supported in the speed reduction mechanism housing portion 65 by a bearing (not shown). Further, a portion of the worm 91 that is connected to the rotating shaft 3 (the other end portion of the rotating shaft 3) is rotatably supported by a rolling bearing 93 (see FIG. 2) disposed in the frame portion 61.

As shown in FIGS. 3 and 7, the worm wheel 92 is housed in the speed reduction mechanism housing portion 65 as described above, and is configured to rotate with the rotation of the worm 91 described above. A boss portion 94 that protrudes toward the bottom plate 62 along the output shaft direction O2 is formed at the center portion (hub portion) of the worm wheel 92. One end portion of the output shaft 95 in the output shaft direction O2 is press-fitted into the boss portion 94 from the frame portion 61 side.
In this case, the other end portion of the output shaft 95 in the output shaft direction O2 protrudes outside the frame portion 61 through the sleeve 82 of the frame portion 61, and an external mechanism for driving a front wiper (not shown) is provided on the protruding portion. Connected. Further, the output shaft 95 is rotatably supported by the above-described sliding bearing 83 in the sleeve 82.

<Relay unit>
Here, the relay unit 101 is disposed on a surface of the worm wheel 92 located on one end side (the frame portion 61 side) along the output shaft direction O2. The relay unit 101 includes an insulator plate 102 made of an insulating material such as a resin, and a relay plate 103 disposed on the insulator plate 102.
The insulator plate 102 has an annular shape having an opening into which the output shaft 95 is loosely inserted, and is placed on a surface of the worm wheel 92 located on one end side along the output shaft direction O2. At the inner peripheral edge of the insulator plate 102, an insertion tube portion 105 is formed that is inserted into the reduced diameter portion of the sleeve 82 described above.

  The insertion tube portion 105 has a stepped shape that is gradually reduced in diameter toward the distal end portion following the shape of the inner surface of the reduced diameter portion 84 of the sleeve 82. The insertion cylinder part 105 is positioned in the output axis direction O2 and the radial direction of the relay unit 101 by the outer peripheral surface being close to or in contact with the inner surface of the reduced diameter part 84. The insertion tube portion 105 is disposed in a gap between the sleeve 82 (the reduced diameter portion 84) and the slide bearing 83.

As shown in FIG. 3, a relay side engaging portion 107 that protrudes toward the worm wheel 92 is formed on a part of the outer peripheral edge of the insulator plate 102 in the circumferential direction around the output shaft 95. .
Further, in the worm wheel 92 described above, a worm side engagement portion 108 that can be engaged with the relay side engagement portion 107 is provided at a position facing the relay side engagement portion 107 in the circumferential direction around the output shaft 95. Is formed. The worm side engagement portion 108 is disposed on the front side in the drawing in the rotational direction of the worm wheel 92 with respect to the relay side engagement portion 107, and is connected to the relay side engagement portion 107 when the worm wheel 92 rotates in the forward direction. Engage (abut). Note that a plurality of ribs 96 extending radially from the center portion and concentrically with the boss portion 94 are formed on both surfaces of the worm wheel 92, and the above-described relay side engagement portion 107 has the above worm side engagement. The joint portion 108 and the rib 96 are disposed with a space therebetween.

The relay unit 101 rotates together with the worm wheel 92 by the engagement of the relay side engaging portion 107 and the worm side engaging portion 108 as the worm wheel 92 rotates as the electric motor 2 rotates. It is supposed to be.
On the other hand, when an external force or the like acts on the front wiper and the worm wheel 92 tries to reversely rotate, the worm side engaging portion 108 is separated from the relay side engaging portion 107 and the engagement therebetween is released. This prevents the relay unit 101 from rotating with respect to the worm wheel 92. That is, the relay side engaging portion 107 and the worm side engaging portion 108 constitute a one-way clutch mechanism for preventing chattering between the worm wheel 92 and the relay unit 101.

  As shown in FIG. 3, the relay plate 103 is made of a conductive material, and is installed on the insulator plate 102 so as to surround the insertion tube portion 105. Specifically, the relay plate 103 has three contact areas 111 to 113 from the inner peripheral side to the outer peripheral side of the insulator plate 102. Each of the contact regions 111 to 113 includes an annular first contact region 111, a C-shaped second contact region 112 that is connected to the inner periphery of the first contact region 111, and an outer peripheral side from the first contact region 111. And a third contact region 113 protruding into the surface. Therefore, a portion aligned in the circumferential direction with respect to the second contact region 112 and a portion aligned in the circumferential direction with respect to the third contact region 113 are non-conductive portions where the insulator plate 102 is exposed.

  The contact portions 57 of the contact plate 56 described above are in sliding contact with the contact regions 111 to 113 and the non-conductive portion in the relay unit 101. In this case, as the worm wheel 92 (output shaft 95) rotates, the contact position between the contact plate 56 (contact portion 57) and the relay plate 103 changes, or the contact / non-contact occurs. 95 rotational positions (front wiper positions) can be detected. A signal detected by the contact plate 56 is output to a control device (not shown) via the connector unit 34 so that rotation control of the electric motor 2 is performed.

In the wiper motor 1 configured as described above, when a wiper switch (not shown) is switched from the OFF position to the LOW position, a driving current is supplied from the battery to the low speed brush 31a of the electric motor 2. Thereby, the electric motor 2 starts driving in the low speed operation mode. Specifically, when the electric motor 2 is driven, the driving force is decelerated by the speed reduction mechanism 4 and then transmitted to the external mechanism of the front wiper via the output shaft 95. As a result, the front wiper is activated so that dust, raindrops, and the like attached to the windshield can be wiped off.
On the other hand, when the wiper switch is switched to the HIGH position, a driving current is supplied from the battery to the high-speed brush 31b of the electric motor 2. As a result, the electric motor 2 starts driving in the high-speed operation mode that is faster than the low-speed operation mode described above.

  In the present embodiment, the tip of the high-speed brush 31b has a narrower circumferential width than the other brushes 31a and 31c. For example, the low-speed brush 31a and the high-speed brush 31b are each in the circumferential direction. It can suppress that it will be in the state (short circuit state) which has contacted across two adjacent segments 24. Thereby, rectification | straightening property can be improved.

  Further, for example, when an external force or the like acts on the output shaft 95 and the worm wheel 92 rotates via the output shaft 95, the engagement between the worm wheel 92 and the relay unit 101 is released, so that the worm wheel 92 Only rotate with respect to the relay unit 101. Therefore, the contact position between the relay unit 101 and the contact plate 56 (for example, the position where the wiper motor 1 is stopped) can be maintained, and chattering at the time of detecting the position of the relay unit 101 and the contact plate 56 can be prevented.

[Assembly method of wiper motor]
Next, a method for assembling the wiper motor 1 will be described. In the following description, a method for assembling the holder unit 32 to the armature 6 will be mainly described.
First, the holder unit 32 to which the brush holder 41 and the like are assembled is assembled to the frame portion 61. Specifically, after the holder unit storage portion 66 of the frame portion 61 and the mounting surface side of the holder unit 32 are arranged to face each other in the rotation axis direction O1, the holder unit 32 is stored in the holder unit storage portion 66. At this time, the positioning unit 37 of the holder unit 32 is engaged in the positioning recess 72 of the holder unit storage unit 66, so that the holder unit 32 is positioned in the rotational axis direction O1 with respect to the frame unit 61.

  Next, the armature 6 is assembled to the holder unit 32 assembled to the frame portion 61. First, the armature 6 and the brush holder stay 33 of the holder unit 32 are opposed to the rotation axis direction O1. In this case, the armature 6 and the holder unit 32 are made to face each other with the commutator 23 of the armature 6 facing the brush holder stay 33 and the mounting surface of the brush holder stay 33 facing the other end side of the rotation axis direction O1. Therefore, in a state where the holder unit 32 is assembled to the frame portion 61, the brush holder 41 of the brush holder stay 33 is inclined inward in the radial direction from one end side to the other end side along the rotation axis direction O1. Is retained.

  In this state, the holder unit 32 is moved closer to the armature 6 side along the rotation axis direction O <b> 1, and the commutator 23 of the armature 6 is inserted into the opening of the brush holder stay 33. The commutator 23 inserted into the opening of the brush holder stay 33 enters between the brush holders 41 on the mounting surface side of the brush holder stay 33. Thereby, the armature 6 and the holder unit 32 are assembled | attached when the segment 24 of the commutator 23 and the brush 31 of the brush holder 41 contact. After that, the wiper motor 1 is completed by sequentially assembling the speed reduction mechanism 4, the bottom plate 62, the yoke 7 and the like to the frame portion 61 to which the holder unit 32 and the armature 6 are assembled.

Here, in this embodiment, since the brush holder 41 extends along the rotation axis direction O1, when the commutator 23 (armature 6) is inserted through the brush holder stay 33 along the rotation axis direction O1, The extending direction of the brush holder 41 and the assembling direction of the armature are the same direction. Therefore, the commutator 23 can smoothly enter between the brush holders 41 (the brushes 31a to 31c) of the brush holder stay 33, and the assembling property can be improved.
In this case, even if the number of magnetic poles is four or more as in this embodiment, the brush holder 41 (brushes 31a to 31c) is arranged with high accuracy at a desired position in the circumferential direction without degrading the assembling property. can do.

  In particular, since the base end portion of the brush holder 41 is positioned on the front side in the assembly direction of the armature 6, when the commutator 23 enters between the brush holders 41, the brush holder 41 is moved radially outward (brush holder 41 It will enter while pushing toward the direction against the urging force. Thereby, since it is not necessary to perform the above-described opening process of spreading the brush holder 41 outward in the radial direction using a jig or the like, it is possible to further improve the assembling property and reduce the manufacturing man-hours and manufacturing costs. Reduction can be achieved.

  Furthermore, in the present embodiment, since the holder unit 32 is formed with the positioning portion 37 for positioning with the frame portion 61, the holder unit 32 and the frame portion 61 are moved in the rotation axis direction O1 via the positioning portion 37. Can be positioned. Thus, after the holder unit 32 is assembled to the frame portion 61, the armature 6 is assembled to the holder unit 32 as described above, whereby the armature 6 can be positioned in the rotational axis direction O1 with respect to the frame portion 61. Thereby, the further improvement of assembly property can be aimed at.

Moreover, in this embodiment, since the connector part 34 and the brush holder 41 are integrally arrange | positioned by the holder unit 32, it is the structure which connects an electric motor and a connector part via the wiring part of a bottom plate like the past. In comparison, the wiring length between the electric motor 2 and the connector portion 34 can be shortened and the wiring layout can be simplified, and the cost can be reduced.
Further, by arranging the connector part 34 and the like in the holder unit 32 and arranging the relay unit 101 on the frame part 61 side, the function of the bottom plate 62 can be reduced (in this embodiment, the frame It is only necessary to have a function of closing the part 61 and protecting the components in the frame part 61). Therefore, the bottom plate 62 can be simplified and the workability can be improved. In this case, the bottom plate 62 can be easily formed by, for example, pressing, so that the cost can be reduced. In the above-described embodiment, the configuration in which the bottom plate 62 is formed of a resin material has been described. However, the configuration is not limited to this, and the bottom plate 62 may be formed of a metal material such as aluminum.

  In addition, since the insertion cylinder portion 105 of the relay unit 101 is positioned at the reduced diameter portion 84 of the frame portion 61, the relay unit 101 can be stably held in the gear housing 5, and the assembly property of the wiper motor 1 can be improved. Can be improved.

Further, since the contact plate 56 is integrally formed with the connector terminal on one end side and the contact portion 57 on the other end side and is insert-molded in the connector portion 34, the number of parts and the number of manufacturing steps can be reduced. it can.
Furthermore, since the brushes 31a to 31c are routed to the connector part 34 via the jumper wires 42, 43, and 45, for example, wiring is made in comparison with a configuration in which the brushes 31a to 31c and the connector part 34 are connected by a bus bar or the like. Can be flexibly routed. Thereby, the freedom degree of wiring layout can be improved.

  In addition, in the present embodiment, since the holder unit housing portion 66 for housing the holder unit 32 is formed in the frame portion 61, the connector portion 34 may protrude outward from the gear housing 5 when viewed from the rotational axis direction O1. Absent. That is, since the outer dimension of the holder unit 32 viewed from the rotation axis direction O1 can be accommodated within the outer dimension of the gear housing 5, the layout can be improved when it is attached to the vehicle body or the like.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the 4-pole-3 brush electric motor 2 is employed has been described. However, the present invention is not limited thereto, and a 6-pole or 8-pole-3 brush electric motor 2 may be employed. . However, the low speed brush 31a and the common brush 31c need to be arranged with a mechanical angle of 60 ° in the case of 6 poles and 45 ° in the case of 8 poles.
Even when the number of poles is 6 or more, the high-speed brush 31b is arranged in a line-symmetric region with respect to the low-speed brush 31a and the common brush 31c, so that the rotational axis 3 is displaced as described above. Can be suppressed.

In addition, as shown in FIG. 8, a choke coil 120 may be disposed as a noise prevention element between the brushes 31 a and 31 b and the power terminal 55. In the example shown in FIG. 8, the choke coil 120 connected to the low speed brush 31a is disposed between the low speed brush 31a and the high speed brush 31b on the brush holder stay 33, and is connected to the high speed brush 31b. A coil 120 is disposed on the bridge portion 35.
According to this configuration, the electromagnetic noise can be reduced by providing the choke coil 120 between the low speed brush 31 a and the high speed brush 31 b and the power terminal 55.
Moreover, the above-described circuit breaker 44, choke coil 120, etc. are provided in the space between the brushes 31a, 31b in the brush holder stay 33, etc., and on the bridge portion 35, etc. without enlarging the holder unit 32 and changing the layout. Therefore, the layout can be improved.

In the above-described embodiment, the connector receiving portion 52 of the connector portion 34 is formed so as to face the one end side in the rotation axis direction O1, but the present invention is not limited to this.
Furthermore, in the above-described embodiment, the case where the brush holder stay 33 is formed in an annular shape has been described. However, the present invention is not limited thereto, and may be, for example, U-shaped as long as the commutator 23 can be inserted.
Moreover, although embodiment mentioned above demonstrated the case where the brush holder stay 33 and the connector part 34 were integrally formed as the holder unit 32, it is not restricted to this.

  Furthermore, you may form the attachment piece to a vehicle body or a front wiper in a bottom plate. Specifically, on the outer peripheral edge of the bottom plate 130 shown in FIG. 9, mounting pieces 131 extending toward the frame portion 61 side along the output shaft direction O2 are spaced apart in the circumferential direction around the output shaft 95. Is formed. These attachment pieces 131 are located outside the bottom wall portion 63 of the frame portion 61 along the output axis direction O2, and the tip portions thereof are bent. An attachment hole 132 through which a fastening member (not shown) is inserted is formed at the tip of the attachment piece 131, and the fastening member is fastened to the vehicle body or the front wiper through the attachment hole 132.

Further, an attachment piece 141 extending toward the frame portion 61 side along the output shaft direction O2 is formed on a part of the bottom plate 140 shown in FIG. The attachment piece 141 includes a plate-like portion 142 that extends to the bottom wall portion 63 side of the frame portion 61, and a semi-cylindrical accommodating portion 143 that is connected to the distal end portion of the plate-like portion 142. For example, a pipe frame 145 that spans between a pair of pivot shafts of a front wiper (not shown) is accommodated in the accommodating portion 143. Further, a through hole 144 that penetrates in the thickness direction is formed in the accommodating portion 143, and a fastening member is fastened to the pipe frame 145 through the through hole 144.
With these configurations, the wiper motor 1 can be easily attached to the vehicle body or the front wiper via the bottom plates 130 and 140.
In addition, a screw thread can also be directly formed in the attachment hole 132 in FIG. 9 and the through hole 144 in FIG. Thereby, the number of parts of the fastening member for fastening to the vehicle body or the front wiper can be reduced. In this case, the bottom plates 130 and 140 may be bottom plates made of high-strength resin, or bottom plates made of metal such as an iron plate.

  In the above-described embodiment, the configuration in which the wiper motor 1 of the present invention is used for driving the front wiper has been described. However, the configuration is not limited to this, and the wiper motor 1 is used for driving a rear wiper or the like, or is used for a general motor other than the wiper motor 1. You may use it.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to replace suitably the component in the embodiment mentioned above by the known component, and you may combine the modification mentioned above suitably.

1. Wiper motor (electric motor)
DESCRIPTION OF SYMBOLS 2 ... Electric motor 3 ... Rotary shaft 6 ... Armature 7 ... Yoke 11 ... Tube part 12 ... Magnet 23 ... Commutator 24 ... Segment 31 ... Brush 31a ... Low speed brush 31b ... High speed brush 31c ... Common brush 33 ... Brush holder stay 34 ... Connector part 41 ... Brush holder 91 ... Worm 92 ... Worm wheel 120 ... Choke coil (noise prevention element)

Claims (7)

A yoke having a cylindrical portion;
A magnet having four or more magnetic poles disposed on the inner peripheral surface of the cylindrical portion;
An armature attached to the rotating shaft and made rotatable inside the yoke;
A commutator attached to the rotating shaft and having a plurality of segments;
A plurality of brushes that slidably contact the segments to supply power;
A brush holder for holding the brush separately;
In an electric motor comprising a brush holder stay that supports the brush holder,
The brush holder stay has an opening through which the commutator can be inserted along the axial direction of the rotating shaft,
Among the segments, the segments having the same potential are short-circuited with a connection line,
The brush
A low speed brush and a high speed brush;
A common brush used in common with the low-speed brush and the high-speed brush,
The low-speed brush and the common brush are arranged at 180 ° intervals in the circumferential direction with an electrical angle,
The high-speed brush is disposed in a second region opposed to the first region between the low-speed brush and the common brush along the circumferential direction in a radial direction with the rotation shaft interposed therebetween,
While having a plurality of terminals electrically connected to the brush, a connector part for connecting to the outside is formed integrally with the brush holder stay via a bridge part,
The distance between the high speed brush and the connector portion is shorter than the distance between the low speed brush and the common brush and the connector portion,
Between the low-speed brush and the high-speed brush in the brush holder stay, a noise prevention element connected to the low-speed brush is disposed,
An electric motor characterized in that an anti-noise element connected to the high-speed brush is disposed in the bridge portion.   The electric motor according to claim 1, wherein the noise prevention element is arranged so that a longitudinal direction of the noise prevention element is along an in-plane direction of the brush holder stay and the bridge portion.   The electric motor according to claim 1, wherein the brush holder stay and the bridge portion are formed on the same surface. The connector part is
A connector base portion extending on the same plane as the brush holder stay and the bridge portion;
The electric motor according to any one of claims 1 to 3, further comprising: a partition wall portion erected from the connector base portion.   5. The electric motor according to claim 1, wherein the high-speed brush has a circumferential width narrower than the low-speed brush and the common brush. A worm coupled to the rotating shaft, and a reduction mechanism having a worm wheel fixed to the output shaft and meshing with the worm to decelerate the rotation of the rotating shaft and output from the output shaft;
A gear housing that houses the speed reduction mechanism and the brush holder stay,
The electric motor according to claim 1, wherein the brush holder stay is formed with a positioning portion that performs axial positioning with respect to the gear housing. The connector part is provided with a contact plate partially embedded in the connector part,
The electric motor according to claim 6, wherein the contact plate is in sliding contact with a relay plate disposed on the worm wheel.

Images