JP5501689B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor provided with a choke coil for noise prevention between a brush slidably contacting a commutator and a power supply terminal connected to a power source.

  An electric motor with a brush is often used as a drive source for electrical components such as a wiper device and a power window device provided in a vehicle.

  The electric motor with a brush includes a commutator fixed to the armature shaft and a pair of brushes that are in sliding contact with the commutator. The drive current supplied to the power supply terminal is commutated at a predetermined timing by the brush and the commutator, and the armature coil. To supply. Also, a resin holder base is mounted on the yoke, each brush is held by a brush holder attached to the holder base so as to be movable back and forth toward the commutator, and each power supply terminal is also attached to the holder base. .

  When using an electric motor with a brush for an electrical component of a vehicle, the noise should be reduced so that the noise generated from the sliding contact portion between the commutator and the brush does not affect the operation of other electrical components. Measures to reduce it are necessary.

  For example, in the electric motor described in Patent Document 1, a choke coil is connected between the power supply terminal and the brush, and noise in the current circuit is absorbed and reduced by the choke coil.

JP 2003-88038 A

  In an electric motor in which a choke coil is provided, a pair of holding walls are provided to be opposed to each other such as a holder base with a space therebetween, and the choke coil is held between these holding walls.

  However, since the diameter tolerance of a normal choke coil is set to be large in order to reduce the cost, in the conventional electric motor, in order to absorb the large diameter tolerance, the distance between the holding walls is set to the diameter of the choke coil. As a result, a gap is generated between each holding wall and the choke coil inserted between the holding walls.

  Therefore, when the vibration of the brush is transmitted to the choke coil via the pigtail during motor operation, the choke coil vibrates between the holding walls, and a load is generated at the connection portion with the pigtail or the power supply terminal. There was a risk of disconnection.

  An object of the present invention is to prevent the vibration of the choke coil and improve the connection reliability of the connection portion of the choke coil with the brush and the power supply terminal.

An electric motor of the present invention is connected between a commutator fixed to an armature shaft, a plurality of brushes held in a brush holder attached to a holder base and in sliding contact with the commutator, and the brush and a power supply terminal. An electric motor having a choke coil and a choke coil holding portion that is provided on the holder base and holds the choke coil, wherein the choke coil holding portions face each other with a space therebetween and increase or decrease the space. A pair of flat holding walls that are elastically deformable in a direction, and a pair of stopper pieces provided on the outer side along the axial direction of the choke coil so that the distance between them is set wider than the length dimension of the choke coil with bets, a pair of said retaining wall is inclined so that the distance of the distal end side than the respective base end is narrowed, the Chi Held across the choke coil Kukoiru from the radially abuts a pair of the stopper piece is characterized in that for positioning the axial direction of the choke coil.

  The electric motor of the present invention is characterized in that the pair of holding walls abut against the choke coil in a state of being elastically deformed toward the radially outer side of the choke coil.

  In the electric motor of the present invention, the holder base is provided with a protruding portion that protrudes to a position between the proximal end portion and the distal end portion of the holding wall, and the choke coil is connected to the proximal end of the holding wall by the protruding portion. It is characterized in that it is held at a position closer to the tip than the part.

  The electric motor of the present invention is characterized in that a claw portion having a semicircular cross section that protrudes toward the front end portion of the counterpart holding wall is provided at the front end portion of each holding wall.

  According to the present invention, the pair of flat holding walls inclined to each other are brought into contact with the choke coil from the radial direction so as to hold the choke coil between the holding walls. The choke coil can be reliably held without causing a gap therebetween. Thereby, the vibration of the choke coil between the holding walls can be prevented, and the connection reliability of the connection portion of the choke coil with the brush or the power supply terminal can be improved.

  According to the present invention, the pair of holding walls are brought into contact with the choke coil while being elastically deformed outward in the radial direction of the choke coil. The choke coil can be held more securely by contact. Further, since the tolerance of the diameter of the choke coil can be absorbed by the elastic deformation of the holding wall, the choke coil can be reliably held even if the tolerance of the choke coil is increased. As a result, the choke coil tolerance can be set large, and the cost of the choke coil, that is, the cost of the electric motor can be reduced.

  According to the present invention, since the claw portion having a semicircular cross section is provided at the tip of each holding wall, the holding performance between the holding walls of the choke coil is improved and the choke coil is inserted between the holding walls. The insertion operation can be facilitated.

  According to the present invention, the projection provided on the holder base holds the choke coil at a position closer to the distal end portion than the proximal end portion of the holding wall. The height can be ensured to be higher than the diameter of the choke coil. Thereby, each holding wall can be easily elastically deformed, and the choke coil can be easily inserted.

It is a perspective view which shows the electric motor which is one embodiment of this invention. It is sectional drawing which shows the internal structure of the wiper motor shown in FIG. It is a front view which shows the detail of the brush unit shown in FIG. (A) is a perspective view which shows the choke coil holding | maintenance part of the state in which the choke coil was mounted | worn, (b) is a perspective view which shows the choke coil holding | maintenance part in the state where the choke coil was removed. It is sectional drawing which follows the AA line shown in FIG. (A)-(c) is sectional drawing which shows the attachment procedure of the choke coil to a choke coil holding part, respectively.

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

  The electric motor 11 shown in FIG. 1 is also called a wiper motor, and is used as a drive source for a wiper device mounted on a vehicle. The electric motor 11 is a motor with a speed reducer in which the motor main body 12 and the speed reducer 13 are formed as one unit, and is fixed to a vehicle body (not shown) at an attachment leg portion 13 a provided in the speed reducer 13.

  As can be seen from FIG. 2, the yoke 14 of the motor main body 12 is formed of a steel plate in a bottomed cylindrical shape, and a gear case 15 of the speed reducer 13 is attached to the open end. A pair of magnets (permanent magnets) 16 are fixed to the inner surface of the yoke 14, and a magnetic field is formed inside the yoke 14 by these magnets 16.

  An armature (armature) 17 is accommodated inside the yoke 14, and this armature 17 is supported inside the yoke 14 by supporting one end of an armature shaft 18 on a bearing 19 fixed to the bottom of the yoke 14. It is free to rotate. The armature core (armature core) 21 fixed to the armature shaft 18 is provided with a plurality of slots 21a arranged in the rotational direction, and each slot 21a is provided with a plurality of armature coils (armature windings) by lap winding. ) 22 is installed.

  A commutator (commutator) 23 is fixed to the armature shaft 18 adjacent to the armature core 21. The commutator 23 is provided with a plurality of segment pieces 23 a arranged in the direction of rotation at equal intervals while being insulated from each other, and each segment piece 23 a is electrically connected to the coil end of the corresponding armature coil 22. Has been.

  A brush unit 31 is attached to the cylindrical portion 15 a connected to the open end of the yoke 14 of the gear case 15. FIG. 3 is a front view showing details of the brush unit shown in FIG. 2, and the brush unit 31 has a resin holder base 32.

  The holder base 32 includes a cylindrical guide wall portion 32a corresponding to the cross-sectional shape of the yoke 14 and a flat base portion 32b perpendicular to the axial direction of the armature shaft 18, and these are integrally formed of a resin material. It has a structured. An insertion hole 32c is provided at the axis of the base portion 32b, and the armature shaft 18 and the commutator 23 are inserted through the insertion hole 32c and penetrate the base portion 32b.

  A pair of brush holders 33 is attached to the base portion 32b. Each of these brush holders 33 is formed in a box shape with one end opened by bending a copper plate or the like, and each of the brush holders 33 is disposed with its axial direction directed toward the center of the insertion hole 32c, that is, the outer peripheral surface of the commutator 23. . The brush holders 33 shift the phase by 90 degrees in the rotation direction of the armature shaft 18 around the insertion hole 32c, that is, the axis of the armature shaft 18, and both the arc-shaped portions 32d and the linear portions 32e of the base portion 32b. Are arranged symmetrically in FIG. 3 adjacent to the boundary portion.

  Each brush holder 33 is equipped with a brush 34 formed of a conductor such as carbon or graphite. These brushes 34 are respectively held by the corresponding brush holders 33 so as to be able to move forward and backward, and are urged by springs 35 provided inside the brush holders 33 to elastically contact (sliding) the outer peripheral surface of the commutator 23. Contact).

  A pair of power supply terminals 36 are attached to the base portion 32b of the holder base. Each power supply terminal 36 is connected to a connector 38 (see FIG. 1) provided on the gear case 15 via a wiring 37 (see FIG. 2) and to a corresponding brush 34. As a result, when a drive current is supplied from a power source (not shown) such as a battery mounted on the vehicle to the power supply terminal 36 via the connector 38, the drive current is converted to a predetermined timing by the brush 34 and the commutator 23. The armature coil 22 is supplied and supplied to the armature coil 22, and electromagnetic force is generated in the armature 17, so that the armature shaft 18 rotates.

  The gear case 15 accommodates a control board 41 having a function as a so-called microcomputer including a plurality of electronic components such as a CPU, a memory, and an FET, and is supplied to the power supply terminal 36 via a wiring 37. The drive current is adjusted by the control board 41, whereby the operation of the motor body 12 is controlled.

  As shown in FIG. 2, the tip portion of the armature shaft 18 protrudes from the yoke 14 and reaches the inside of the gear case 15, and a worm 42 is integrally formed on the outer peripheral surface of the portion protruding inside the gear case 15. ing. Further, a worm wheel 44 fixed to the output shaft 43 is rotatably accommodated in the gear case 15, and the worm 42 is engaged with the worm wheel 44. That is, the worm gear mechanism 45 (deceleration mechanism) is constituted by the worm 42 and the worm wheel 44, and the rotation of the armature shaft 18 is decelerated by the worm gear mechanism 45 and output from the output shaft 43.

  As shown in FIG. 3, in order to reduce noise generated from the sliding contact portion between the commutator 23 and the brush 34 when the motor main body 12 is operated, between each brush 34 and the corresponding power supply terminal 36, A choke coil 46 (noise prevention element) is connected to each.

  FIG. 4A is a perspective view showing the choke coil holding portion with the choke coil mounted, and FIG. 4B is a perspective view showing the choke coil holding portion with the choke coil removed. 5 is a cross-sectional view taken along the line AA shown in FIG. 3, and FIGS. 6A to 6C are cross-sectional views showing a procedure for mounting the choke coil to the choke coil holding portion.

  The choke coil 46 is formed by being wound around the outer periphery of a cylindrical core material 47 and is fixed to the core material 47. The core material 47 is formed to be longer in the axial direction than the choke coil 46, and both end portions thereof protrude in the axial direction from both end portions of the choke coil. One coil end of the choke coil 46 is connected to the pigtail 34 a of the corresponding brush 34, and the other coil end is connected to the corresponding power supply terminal 36.

  A pair of choke coil holding portions 51 are provided on the base portion 32 b of the holder base 32 in order to hold the choke coil 46. These choke coil holding portions 51 are disposed on the side of the arc-shaped portion 32d between the brush 34 and the power supply terminal 36 on the base portion 32b, and the choke coil 46 is parallel to the base portion 32b and in a straight portion 32e. On the other hand, it is held in a posture directed in a direction orthogonal to the direction.

  Next, details of the choke coil holding portion 51 will be described. Since the two choke coil holding portions 51 have basically the same structure, only the structure of one choke coil holding portion 51 will be described below.

  As shown in FIGS. 4 and 5, the choke coil holding portion 51 includes a pair of flat holding walls 52 that protrude from the base portion 32 b of the holder base 32. These holding walls 52 are formed integrally with the base portion 32b of the holder base 32 by a resin material, and are respectively parallel to the axis of the choke coil 46 and arranged to face each other with a space therebetween. That is, each holding wall 52 is disposed such that the base end portion and the tip end portion extend in a direction orthogonal to the straight line portion 32e. Further, as shown in FIG. 5, each holding wall 52 is inclined by an angle α toward the inside, that is, the choke coil 46 side, with respect to the direction perpendicular to the base portion 32b. Thereby, the space | interval of each holding | maintenance wall 52 becomes narrower in the side of the front-end | tip part (end part of the direction protruded from the base part 32b) side than the base end part (end part by the side of the base part 32b). ing.

  As shown in FIG. 5, a claw portion 53 that extends along the edge portion of each holding wall 52 is integrally provided at the distal end portion of each holding wall 52. Each of these claw portions 53 protrudes from the tip of the holding wall 52 toward the tip of the counterpart holding wall 52, that is, inward of the choke coil holding portion 51 in parallel with the base portion 32b. The cross-sectional shape of the tip is semicircular.

  As shown in FIG. 6A, the interval W <b> 1 at the tip of each holding wall 52 in the state where the choke coil 46 is not inserted is narrower than the diameter D of the choke coil 46. In addition, the interval W2 in the portion of the holding wall 52 that holds the choke coil 46 in a state where the choke coil 46 is not inserted has the same value as the minimum tolerance diameter (the smallest diameter within the tolerance range) of the choke coil 46. Is set.

  A portion between the holding walls 52 of the base portion 32b is provided with a die-cutting hole 54, and both side portions of the hole 54 along the axial direction of the choke coil 46 are shown in FIG. As described above, a convex portion 55 for supporting the choke coil 46 is provided. Each of these convex portions 55 is formed in a block shape protruding from the surface of the base portion 32b to a position where the height H (see FIG. 5) is between the base end portion and the tip end portion of the holding wall 52. The upper surface is a flat support surface 55a.

  Further, stopper pieces 56 are respectively provided on the outer sides along the axial direction of the choke coil 46 of the respective convex portions 55 of the base portion 32b. These stopper pieces 56 are each formed in a block shape having a height higher than that of the convex portion 55, and the interval between them is set slightly larger than the length dimension of the core material 47 of the choke coil 46.

  In addition, each convex part 55 and each stopper piece 56 are also integrally formed with the base part 32b of the holder base 32, respectively by the resin material.

  As shown in FIGS. 6A to 6C, the choke coil 46 is inserted into the choke coil holding portion 51 from the direction perpendicular to the base portion 32 b toward the holding walls 52. At this time, each holding wall 52 is formed in a flat plate shape with a resin material, and is elastically deformable in the direction in which the distance between the holding walls 52 increases or decreases, that is, in the radial inner and outer directions with respect to the choke coil 46. Each holding wall 52 can be elastically deformed radially outward of the choke coil 46, and the choke coil 46 can be inserted between the holding walls 52 from the tip side. Further, the claw portion 53 of each holding wall 52 has a semicircular cross section at the tip, so that the choke coil 46 is prevented from being caught by the claw portion 53 and the choke coil 46 can be easily inserted. can do.

  When the choke coil 46 is inserted between the holding walls 52, that is, in the choke coil holding portion 51, both end portions of the core material 47 face the stopper piece 56, and the choke coil 46 is positioned in the axial direction. Further, the outer peripheral surface of the choke coil 46 abuts on the support surface 55 a of each convex portion 55 and the opposite side portion is pressed by the claw portion 53. Thereby, the choke coil 46 is supported by the support surface 55a of the convex portion 55 and is held by the choke coil holding portion 51 at a position higher than the base portion 32b on the distal end side with respect to the proximal end portion of the holding wall 52. The

  When the choke coil 46 is positioned at a predetermined position of the choke coil holding portion 51, the pair of holding walls 52 abut against the outer peripheral surface of the choke coil 46 from the radial direction on the inner surfaces thereof. As a result, the choke coil 46 is sandwiched between the holding walls 52 and held between the holding walls 52 while being positioned in the radial direction. At this time, since each holding wall 52 is in contact with the outer peripheral surface of the choke coil 46, there is no gap between each holding wall 52 and the choke coil 46.

  Thus, in the present invention, each holding wall 52 is brought into contact with the choke coil 46 from the radial direction, and the choke coil 46 is sandwiched and held between the holding walls 52. The choke coil 46 can be reliably held without generating a gap with the wall 52. Therefore, the choke coil 46 is prevented from vibrating between the holding walls 52 due to vibration transmitted from the brush 34 or the like when the motor body 12 is operated, and the choke coil 46 is connected to the brush 34 or the power supply terminal 36. The connection reliability of the part can be increased. Further, since vibration between the holding walls 52 of the choke coil 46 is prevented, noise generated when the choke coil 46 vibrates between the holding walls 52 can be reduced.

  In the present invention, the claw portion 53 provided at the tip of each holding wall 52 is formed in a semicircular cross section, so that the holding wall 52 of the choke coil 46 is improved while improving the holding performance of the choke coil 46. It is possible to facilitate the insertion work between the two.

  Further, in the present invention, the choke coil 46 is held at the position of the height H closer to the distal end side than the proximal end portion of the holding wall 52 by the convex portion 55 provided on the base portion 32b. The height from the proximal end portion to the distal end portion of the wall 52 can be ensured to be higher than the diameter D of the choke coil 46. Thereby, each holding wall 52 can be easily elastically deformed in the radial direction of the choke coil 46, and the operation of inserting the choke coil 46 into the choke coil holding portion 51 can be further facilitated.

  By the way, as described above, the interval W <b> 2 at the portion of the holding wall 52 that holds the choke coil 46 is set to the same value as the minimum tolerance diameter of the choke coil 46. Therefore, when the diameter D of the choke coil 46 is larger than the minimum tolerance diameter, the diameter D of the choke coil 46 becomes larger than the interval W2 in the portion of the holding wall 52 that holds the choke coil 46, and each holding wall 52 abuts on the choke coil 46 while being elastically deformed toward the radially outer side of the choke coil 46. In this case, each holding wall 52 holds the choke coil 46 in a state where an elastic force due to its elastic deformation is applied, so that the choke coil can be held more reliably.

  In this embodiment, the interval W2 between the holding walls 52 in the portion holding the choke coil 46 is set to the same value as the minimum tolerance diameter of the choke coil 46. However, the present invention is not limited to this. You may make it set the space | interval W2 of the holding wall 52 in the part holding the coil 46 to a value smaller than the tolerance minimum diameter of the choke coil 46. In this case, each holding wall 52 comes into contact with any choke coil 46 in an elastically deformed state toward the outer side in the radial direction, and reliably holds the choke coil 46 in a state where the elastic force is applied. be able to.

  As described above, in the present invention, the holding wall 52 is brought into contact with the choke coil 46 while being elastically deformed outward in the radial direction of the choke coil 46, so that each holding wall 52 is subjected to an elastic force. Can be held in contact with the choke coil 46 to hold the choke coil 46 more reliably. Further, with such a structure, even if the tolerance of the diameter D of the choke coil 46 is set large, the choke coil 46 can be reliably held between the holding walls 52, so that the tolerance of the choke coil 46 is reduced. By setting it large, the cost, that is, the cost of the electric motor 11 can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the case where the present invention is applied to the electric motor 11 used as the drive source of the vehicle wiper device is shown, but the present invention is not limited to this, for example, the drive source of the vehicle power window device The present invention may be applied to an electric motor used for other purposes such as a power window motor used as a fan motor or a fan motor used as a drive source of a radiator cooling device.

DESCRIPTION OF SYMBOLS 11 Electric motor 12 Motor main body 13 Reduction gear 13a Mounting leg part 14 Yoke 15 Gear case 15a Cylindrical part 16 Magnet 17 Armature 18 Armature shaft 21 Armature core 21a Slot 22 Armature coil 23 Commutator 23a Segment piece 31 Brush unit 32 Holder base 32a Guide wall part 32b Base portion 32c Insertion hole 32d Arc-shaped portion 32e Linear portion 33 Brush holder 34 Brush 34a Pigtail 35 Spring 36 Power supply terminal 37 Wiring 38 Connector 41 Control board 42 Warm 43 Output shaft 44 Warm wheel 45 Warm gear mechanism 46 Choke coil 47 Core material 51 Choke Coil holding part 52 Holding wall 53 Claw part 54 Hole 55 Convex part 55a Support surface 56 Stopper piece α Angle W1 D The diameter W2 interval H Height

Claims (4)

A commutator fixed to the armature shaft, a plurality of brushes held by a brush holder attached to a holder base and slidingly contacting the commutator, a choke coil connected between the brush and a power supply terminal, and the holder base An electric motor having a choke coil holding portion that is provided to hold the choke coil,
The choke coil holding portions are opposed to each other with a space therebetween and elastically deformable in a direction to increase or decrease the space, and provided on the outer side along the axial direction of the choke coil. A pair of stopper pieces, each of which is set wider than the length of the choke coil ,
The pair of holding walls are inclined so that the distance on the tip end side is narrower than the base end side, and abut against the choke coil from the radial direction and hold the choke coil therebetween, and the pair of the stoppers The piece performs an axial positioning of the choke coil .   2. The electric motor according to claim 1, wherein the pair of holding walls abut against the choke coil in a state of being elastically deformed radially outward of the choke coil.   3. The electric motor according to claim 1, wherein a convex portion that protrudes to a position between a proximal end portion and a distal end portion of the holding wall is provided on the holder base, and the choke coil is held by the convex portion. An electric motor characterized by being held at a position closer to a distal end portion than a base end portion of a wall.   The electric motor according to any one of claims 1 to 3, wherein a claw portion having a semicircular cross section is provided at a distal end portion of each holding wall and protrudes toward a distal end portion of the counterpart holding wall. An electric motor characterized by that.

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