JP2011083125A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor that prevents misalignment between an armature shaft and a worm shaft. <P>SOLUTION: The armature shaft 17 of an armature 16 is pivotally supported by an armature side bearing 14b. A plurality of feed brushes 22 are arranged on the outer circumference of a commutator 20 fixed to the armature shaft 17, and each feed brush 22 is urged toward the commutator 20 by means of a torsion coil spring. A reduction gear mechanism 32 which slows down rotation of the armature shaft 17 has a worm shaft 35 connected to the armature shaft 17 to rotate together, and the worm shaft 35 is pivotally supported by a worm side bearing 34a. The armature side bearing 14b is arranged so that the central axis L7 is offset from the central axis L2 of the worm side bearing 34a in the direction opposite to the radial component F3 of resultant force of the plurality of feed brushes 22 which press the commutator 20. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a motor in which a current is supplied to an armature through a power supply brush.

  2. Description of the Related Art Conventionally, there is a motor that outputs the rotational movement of an armature generated in a motor unit by decelerating it by a reduction mechanism of a reduction unit connected to the motor unit. For example, in the motor described in Patent Document 1, the armature includes an armature shaft that is pivotally supported by a pair of armature-side bearings, and a cylindrical commutator fixed to the armature shaft. A pair of power supply brushes are disposed on the outer periphery of the commutator, and each power supply brush is urged toward the commutator by an urging means such as a spring to press the commutator. The speed reduction mechanism includes a worm shaft that is pivotally supported by a pair of worm side bearings and is drivingly connected to the armature shaft, and a worm wheel that meshes with a screw-tooth-shaped worm portion formed on the worm shaft. I have. When an electric current is supplied to the armature via the power supply brush, the armature is rotated, the rotational movement of the armature is transmitted from the armature shaft to the worm shaft, and the rotational motion of the worm shaft is The output is decelerated by the motor and the worm wheel.

JP 2009-11076 A

  By the way, in order to facilitate the insertion of the armature shaft into the armature side bearing and smooth rotation of the armature shaft, a slight gap is provided between the inner peripheral surface of the armature side bearing and the outer peripheral surface of the armature shaft. It has been. Therefore, as in the motor described in Patent Document 1, when the two power supply brushes are arranged 90 degrees apart from each other in the rotation direction of the armature on the outer periphery of the commutator, the two power supply brushes press the commutator. The armature shaft is moved in the direction of the resultant force of the pressing force by a slight gap between the inner peripheral surface of the armature-side bearing and the outer peripheral surface of the armature shaft. When the armature shaft is moved by the pressing force of the power supply brush, there arises a problem that the central axis of the armature shaft is shifted from the central axis of the worm shaft. Such an axial misalignment between the armature shaft and the worm shaft is a cause of generation of vibration and abnormal noise when the motor is driven.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a motor capable of suppressing an axial deviation between an armature shaft and a worm shaft.

  In order to solve the above-mentioned problem, an invention according to claim 1 is directed to an armature having an armature shaft and a commutator fixed to the armature shaft, a pair of armature-side bearings that support the armature shaft, and the commutation A plurality of power supply brushes arranged on the outer periphery of the child, a plurality of urging means for urging each of the power supply brushes toward the commutator, and a worm shaft connected to the armature shaft so as to be integrally rotatable. A motor that includes a speed reduction mechanism that decelerates rotation of the armature shaft and a pair of worm side bearings that support the worm shaft, and the resultant force of the pressing force that the plurality of power supply brushes press the commutator does not become zero. The pair of armature side bearings are arranged such that the center axis thereof is offset with respect to the center axis of the worm side bearing in the direction opposite to the radial component of the resultant force. Are you as its gist.

  According to this configuration, the pair of armature-side bearings are arranged such that the central axis thereof is offset in the opposite direction to the radial component of the resultant force of the pressing force from the plurality of power supply brushes with respect to the central axis of the worm-side bearing. Has been. When a pressing force is applied to the commutator from the plurality of power supply brushes, the armature shaft is pressed against the pair of armature-side bearings in the direction of the radial component in the resultant force of the pressing force from the plurality of power supply brushes. The central axis of the armature shaft is moved in the direction of the radial component in the resultant force of the pressing force from the plurality of power supply brushes. Therefore, the center axis of the armature shaft approaches the center axis of the pair of worm side bearings, that is, the center axis of the worm shaft supported by the pair of worm side bearings. As a result, it is possible to suppress the axial displacement between the armature shaft and the worm shaft, and it is possible to suppress the occurrence of vibration and abnormal noise due to the axial displacement between the armature shaft and the worm shaft.

  According to a second aspect of the present invention, in the motor according to the first aspect of the present invention, the motor includes a yoke housing that houses the armature, and a magnet that is fixed to an inner peripheral surface of the yoke housing. And an armature core made of a metal magnetic material fixed to the armature shaft and facing the magnet in the radial direction, and a gap between the armature core and the magnet is pressed by a radial component of the resultant force The gist is that the part on the pressing direction side by the radial component of the resultant force is narrower than the part on the opposite side.

  According to the same configuration, the gap between the armature core and the magnet is caused by the radial component of the combined force rather than the portion opposite to the pressing direction by the radial component of the combined force of the pressing force from the plurality of power supply brushes. Since the portion on the pressing direction side is narrower, the armature core is attracted in the same direction as the radial component in the resultant force of the pressing force from the plurality of power supply brushes by the attractive force of the magnet. Therefore, the armature shaft to which the armature core is fixed is also drawn together with the armature core in the same direction as the radial component of the combined force. Therefore, the armature shaft is pressed against the armature-side bearing by the magnet's attractive force, so that the posture of the armature shaft is easily stabilized. As a result, the armature shaft and the worm shaft are easily maintained in a state in which the axial deviation is suppressed.

  According to a third aspect of the present invention, there is provided a yoke housing, a magnet fixed to the inner peripheral surface of the yoke housing, an armature shaft, an armature shaft, fixed to the armature shaft, and a radial direction of the magnet An armature core facing the armature and an armature having a commutator fixed to the armature shaft, a pair of armature-side bearings that pivotally support the armature shaft, and a plurality of power supply brushes arranged on the outer periphery of the commutator; A plurality of urging means for urging each of the power supply brushes toward the commutator; and a speed reduction mechanism that has a worm shaft connected to the armature shaft so as to be integrally rotatable, and decelerates the rotation of the armature shaft; A motor that includes a pair of worm side bearings that support the worm shaft, and the resultant force of the pressing force by which the plurality of power supply brushes press the commutator does not become zero The armature-side bearing and the worm-side bearing are arranged such that their center axes are aligned with each other, and a gap between the armature core and the magnet depends on a radial component of the resultant force The gist is that the portion on the opposite side to the pressing direction by the radial component of the resultant force is narrower than the portion on the pressing direction side.

  According to the same configuration, the gap between the armature core and the magnet is greater in the pressing direction due to the radial component of the resultant force than the portion on the pressing direction side due to the radial component of the resultant force of the pressing force from the plurality of power supply brushes. Therefore, the armature core is attracted in the direction opposite to the radial component of the combined force by the attractive force of the magnet. Therefore, the armature shaft is suppressed from moving in the direction of the radial component of the resultant force of the pressing force from the plurality of power supply brushes, and the center axis of the armature shaft is prevented from deviating from the center axis of the pair of worm side bearings. The As a result, it is possible to suppress the axial displacement between the armature shaft and the worm shaft, and it is possible to suppress the occurrence of vibration and abnormal noise due to the axial displacement between the armature shaft and the worm shaft.

  ADVANTAGE OF THE INVENTION According to this invention, the motor which can suppress the axial shift of an armature shaft and a worm shaft can be provided.

Sectional drawing of a motor. The top view of a brush holder. The partial expanded sectional view of a motor. The partial expanded sectional view of the motor of another form. The partial expanded sectional view of the motor of another form.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows a motor of this embodiment. This motor is used, for example, as a drive source for a power window device that raises and lowers a window glass of a vehicle. As shown in FIG. 1, the motor includes a motor unit 1 that generates a rotational motion, and a speed reduction unit 2 that is connected to the motor unit 1 and decelerates and outputs the rotational motion generated by the motor unit 1. Has been.

  The motor unit 1 has a bottomed cylindrical yoke housing 11, and a pair of magnets 12 are fixed to the inner peripheral surface of the yoke housing 11 so as to face each other. In addition, a bearing housing portion 11 a is formed in the center of the bottom of the yoke housing 11 so as to protrude outward from the yoke housing 11 and open to the inside of the yoke housing 11. A thrust plate 13 is accommodated in the bearing accommodating portion 11a so as to contact the bottom surface of the bearing accommodating portion 11a, and is cylindrically fixed to the inner peripheral surface of the bearing accommodating portion 11a. A first armature side bearing 14a is accommodated, and a steel ball 15 is disposed inside the armature side bearing 14a. Further, the opening of the yoke housing 11 is provided with a flange portion 11b extending toward the outer peripheral side.

  An armature 16 is disposed between the pair of magnets 12 inside the yoke housing 11. An armature shaft 17 of the armature 16 has a cylindrical shape, and an armature core 19 made of a metal magnetic material and having an armature coil 18 wound around the armature shaft 17 and a cylindrical commutator 20 are externally fitted. Has been fixed. The commutator 20 is fixed to the front end side of the armature shaft 17 relative to the armature core 19 (that is, the opening side of the yoke housing 11), and the armature core 19 faces the magnet 12 in the radial direction.

  A base end portion of the armature shaft 17 (that is, an end portion on the bottom side of the yoke housing 11) is inserted into the first armature side bearing 14a and is pivotally supported by the first armature side bearing 14a. The base end surface of the armature shaft 17 abuts on the steel ball 15, and the steel ball 15 and the thrust plate 13 receive the thrust load of the armature shaft 17.

  A brush holder 21 made of an insulating resin material is inserted into the opening of the yoke housing 11. As shown in FIGS. 1 and 2, the brush holder 21 is formed in a plate shape having an outer shape corresponding to the inner peripheral surface of the yoke housing 11, and in the direction of the central axis L <b> 1 of the armature shaft 17. Are arranged adjacent to the commutator 20. As shown in FIG. 1, the brush holder 21 holds a cylindrical second armature-side bearing 14b that forms a pair with the first armature-side bearing 14a at the center thereof. The armature shaft 17 of the armature 16 has a tip side portion (that is, a portion on the opening side of the yoke housing 11) that penetrates the second armature side bearing 14b and protrudes into the speed reduction portion 2, and a pair of armature shafts 17 is provided. The first and second armature side bearings 14a and 14b are pivotally supported.

  As shown in FIG. 2, the brush holder 21 includes two brush holding portions 21 a on the outer peripheral side of the commutator 20 at positions facing the commutator 20 in the radial direction. The two brush holding portions 21a each have a rectangular tube shape extending along the radial direction of the commutator 20, and the commutator 20 (the armature 16) on one end side (right side in FIG. 2) of the brush holder 21 in the longitudinal direction. ) In the rotational direction of 90).

  Each brush holding portion 21a is inserted with a square pole-shaped power supply brush 22, and each power supply brush 22 is held by the brush holding portion 21a, thereby rotating the commutator 20 (armature 16). They are arranged 90 ° apart from each other in the direction. Each power supply brush 22 is movable along the radial direction of the commutator 20 while being guided by the brush holding portion 21a, and a torsion coil as an urging means disposed on the side of the brush holding portion 21a. By urging the rear end portion by the spring 23, the front end portion is slidably pressed against the outer peripheral surface of the commutator 20.

  Each power supply brush 22 is connected to one end of a pigtail 24, and the other end of each pigtail 24 is a terminal provided on the other end side in the longitudinal direction of the brush holder 21 (left side in FIG. 2). Each is connected to a pair of terminals 25 held by the holding portion 21b. As shown in FIGS. 1 and 2, each terminal 25 protrudes from the brush holder 21 and is provided on the side of the yoke housing 11, and a connector portion into which an external connector (not shown) for supplying current is inserted. 26. Accordingly, the current supplied from the external connector to the connector portion 26 is supplied to the armature coil 18 via the terminal 25, the pigtail 24, the power supply brush 22 and the commutator 20.

  As shown in FIG. 1, the speed reduction portion 2 is formed by housing a speed reduction mechanism 32 for reducing the rotational movement of the armature shaft 17 in a gear housing 31 connected to the yoke housing 11.

  The gear housing 31 is fixed to the flange portion 11 b of the yoke housing 11 with a plurality of screws 33. The gear housing 31 is provided with a clutch housing recess 31a in the direction of the central axis L1 of the armature shaft 17 so as to be connected to the inside of the yoke housing 11, and further from the bottom of the clutch housing recess 31a, the armature shaft 17 is further extended. A worm shaft housing recess 31b is provided along the direction of the central axis L1.

  A pair of first and second worm side bearings 34a and 34b are arranged at both axial ends of the worm shaft housing recess 31b. The first and second worm side bearings 34a and 34b are formed in a cylindrical shape, and are fixed to the inner peripheral surface of the worm shaft housing recess 31b so that the center axis lines L2 and L3 are aligned. The first and second worm side bearings 34a and 34b support both ends in the axial direction of the substantially cylindrical worm shaft 35 housed in the worm shaft housing recess 31b, and the center of the worm shaft 35 The axis L4 and the central axes L2 and L3 of the first and second worm side bearings 34a and 34b are on a straight line. Further, in the worm shaft housing recess 31b, the steel ball 36 that contacts the tip of the worm shaft 35 (ie, the end opposite to the motor unit 1) and the tip of the worm shaft 35 are made of the same steel. A thrust plate 37 disposed so as to interpose the ball 36 is accommodated. These steel balls 36 and thrust plate 37 receive the thrust load of the worm shaft 35.

  A screw-like worm portion 35 a is formed at a substantially central portion in the axial direction of the worm shaft 35. The worm shaft 35 is drivably coupled to the distal end portion of the armature shaft 17 through the clutch 38 housed in the clutch housing recess 31a at the base end portion. The clutch 38 operates so as to transmit the rotational motion from the armature shaft 17 side to the worm shaft 35 while not transmitting the rotational motion from the worm shaft 35 side to the armature shaft 17.

  In the gear housing 31, a wheel housing recess 31c connected to the worm shaft housing recess 31b is formed on the side of the worm shaft housing recess 31b, and a disc-shaped worm is formed in the wheel housing recess 31c. A wheel 39 is accommodated. The worm wheel 39 is supported by the gear housing 31 so as to be rotatable about the central axis L5 of the worm wheel 39, and meshes with the worm portion 35a of the worm shaft 35. The worm wheel 39 constitutes the speed reduction mechanism 32 together with the worm shaft 35. Further, an output shaft 40 that protrudes to the outside of the gear housing 31 is provided at the central portion in the radial direction of the worm wheel 39 so as to be able to rotate integrally with the worm wheel 39. The output shaft 40 is connected to a known window regulator (not shown) for raising and lowering the window glass of the vehicle.

  In the motor configured as described above, when current is supplied to the armature 16 via the power supply brush 22 and the armature 16 is rotated, the rotational movement of the armature shaft 17 is transferred to the worm shaft 35 via the clutch 38. Communicated. The rotational motion transmitted to the worm shaft 35 is decelerated by the worm shaft 35 and the worm wheel 39 and output from the output shaft 40. Then, the window regulator connected to the output shaft 40 is operated, and the window glass is raised or lowered according to the rotation direction of the output shaft 40.

  Here, as shown in FIGS. 1 and 3, generally, the inner diameters of the first and second armature-side bearings 14a and 14b are set so that the armature shaft 17 can be easily inserted, and the armature shaft 17 The armature shaft 17 is formed to be slightly larger than the outer diameter so that the shaft support can be performed satisfactorily. Therefore, a slight gap exists between the inner peripheral surfaces of the first and second armature-side bearings 14 a and 14 b and the outer peripheral surface of the armature shaft 17. In FIGS. 1 and 3, a slight gap is exaggerated and enlarged between the inner peripheral surfaces of the first and second armature-side bearings 14 a and 14 b and the outer peripheral surface of the armature shaft 17. In addition, as shown in FIG. 2, the two power supply brushes 22 urged by the torsion coil springs 23 are disposed 90 ° apart from each other in the rotation direction of the armature 16, and thus the two power supply brushes 22. However, the resultant force of the pressing force that presses the commutator 20 does not become zero. Accordingly, as shown in FIGS. 1 to 3, the armature 16 has the first and second armature-side bearings 14 a and 14 b and the armature when the commutator 20 is pressed by the two power supply brushes 22. Within the range of the gap between the shaft 17, it is moved in the direction of the radial component of the resultant force of the pressing force from each power supply brush 22. In FIG. 2, the radial component of the pressing force with which one power supply brush 22 presses the commutator 20 is indicated by an arrow F1, and the radial component of the pressing force with which the other power supply brush 22 presses the commutator 20 is indicated by an arrow F2. The radial component of the resultant force of the pressing force of the two power supply brushes 22 is indicated by an arrow F3.

  Therefore, in the motor of this embodiment, the arrangement positions of the first and second armature-side bearings 14a and 14b are determined in consideration of the radial component F3 of the resultant force of the two power supply brushes 22 pressing the commutator 20. It is set. More specifically, the first and second armature side bearings 14a and 14b have center axis lines L6 and L7 of the armature side bearings 14a and 14b, and center axis lines L2 and L3 of the first and second worm side bearings 34a and 34b ( That is, with respect to the central axis L4) of the worm shaft 35, it is held by the brush holder 21 while being offset in a direction opposite to the direction of the radial component F3 in the resultant force of the pressing forces of the two power supply brushes 22. The amount by which the central axis L6, L7 of the first and second armature side bearings 14a, 14b is offset in the radial direction with respect to the central axis L2, L3 of the first and second worm side bearing 34a, 34b is two power feeds. When the commutator 20 is pressed by the brush 22 and the armature shaft 17 is pressed against the first and second armature-side bearings 14b, the central axis L1 of the armature shaft 17 and the first and second worm-side bearings 34a and 34b. The central axes L2 and L3 (that is, the same as the central axis L4 of the worm shaft 35) are set to an amount that is in a straight line.

  Therefore, when the two power supply brushes 22 are pressed against the commutator 20, the armature 16 is moved in the direction of the radial component F <b> 3 of the resultant force of the pressing force by the pressing force of the two power supply brushes 22 pressing the commutator 20. The armature shaft 17 is moved and pressed against the first and second armature side bearings 14a and 14b. As a result, the central axis L1 of the armature shaft 17 is in the direction of the radial component F3 in the resultant force of the pressing force of the two power supply brushes 22 with respect to the central axes L6 and L7 of the first and second armature-side bearings 14a and 14b. The first and second worm side bearings 34a and 34b are arranged on the same straight line as the center axes L2 and L3. That is, the central axis L1 of the armature shaft 17 and the central axis L4 of the worm shaft 35 are arranged on the same straight line, and the armature shaft 17 and the worm shaft 35 are coaxial.

As described above, according to the present embodiment, the following operational effects are obtained.
(1) The pair of first and second armature-side bearings 14a and 14b has two power supply brushes whose center axes L6 and L7 are in relation to the center axes L2 and L3 of the first and second worm side bearings 34a and 34b. It arrange | positions so that it may be offset in the opposite direction to the radial direction component F3 of the resultant force of the pressing force from 22. When a pressing force is applied to the commutator 20 from the two power supply brushes 22, the armature shaft 17 presses the pair of first and second armature side bearings 14a and 14b from the two power supply brushes. Therefore, the central axis L1 of the armature shaft 17 is moved in the direction of the same radial component F3. Accordingly, the central axis L1 of the armature shaft 17 is pivotally supported by the central axes L2 and L3 of the paired first and second worm side bearings 34a and 34b, that is, the first and second worm side bearings 34a and 34b. The worm shaft 35 approaches the central axis L4. As a result, the axial deviation between the armature shaft 17 and the worm shaft 35 can be suppressed, and the generation of vibration and noise due to the axial deviation between the armature shaft 17 and the worm shaft 35 can be suppressed.

  (2) Since the second armature side bearing 14b is held by the brush holder 21 made of a resin material, the position of the second armature side bearing 14b is set so that the central axis L7 of the second armature side bearing 14b is the first and second It can be easily set so as to be offset from the central axes L2 and L3 of the worm side bearings 34a and 34b.

  (3) The first and second armature-side bearings 14a and 14b forming a pair are when the commutator 20 is pressed by the two power supply brushes 22 and the armature shaft 17 is pressed against the first and second armature-side bearings 14b. The central axis L2 of the first and second worm side bearings 34a, 34b is arranged so that the central axis L1 of the armature shaft 17 and the central axes L2, L3 of the first and second worm side bearings 34a, 34b are in a straight line. , L3 are offset from the central axes L6 and L7 in the direction opposite to the radial component F3 in the resultant force of the pressing force from the two power supply brushes 22. Therefore, when the commutator 20 is pressed by the two power supply brushes 22, the central axes L2 and L3 of the first and second worm side bearings 34a and 34b paired with the central axis L1 of the armature shaft 17 are aligned. Therefore, the axial deviation between the armature shaft 17 and the worm shaft 35 can be further suppressed, and the generation of vibration and noise due to the axial deviation between the armature shaft 17 and the worm shaft 35 can be further suppressed.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the two power supply brushes 22 are disposed at positions that are 90 ° apart from each other in the rotation direction of the armature 16. However, if the resultant force of the pressing force with which the two power supply brushes 22 press the commutator 20 does not become zero (that is, the angle between the two power supply brushes 22 is not 180 °), the angle between the two power supply brushes 22 Is not limited to 90 °, and may be 45 ° or the like.

  -The motor of the said embodiment is the structure provided with two electric supply brushes 22. However, the number of the power supply brushes 22 provided in the motor may be three or more as long as the resultant force of the pressing force that presses the commutator 20 does not become zero. For example, a motor provided with three power supply brushes 22 of a common brush, a low speed driving brush, and a high speed driving brush, which is used as a driving source of a vehicle wiper device capable of switching the operation speed of the vehicle wiper between a low speed and a high speed. The present invention may be embodied in the following. In this case, the first and second armature side bearings 14a and 14b are connected to the common brush, with respect to the central axis L2 and L3 of the first and second worm side bearings 34a and 34b (that is, the central axis L4 of the worm shaft 35). The low-speed driving brush and the high-speed driving brush are arranged such that their central axes L6 and L7 are offset in the direction opposite to the direction of the radial component of the resultant force of the pressing force pressing the commutator 20.

In the above embodiment, the second armature-side bearing 14b is held by the brush holder, but may be held by the gear housing 31.
As shown in FIG. 4, the radial gap (air gap) between the armature core 19 and the magnet 12 is opposite to the pressing direction by the radial component F3 of the resultant force of the pressing force of the two power supply brushes 22. The part on the pressing direction side (that is, the front side in the pressing direction) by the radial component F3 of the combined force may be narrower in the radial direction than the part on the rear side (that is, the rear side in the pressing direction). In FIG. 4, a gap between the armature core 19 on the side opposite to the pressing direction by the radial component F3 and the magnet 12 is indicated by G1, and the armature core 19 on the pressing direction side by the radial component F3 is illustrated. The gap between the magnet 12 and the magnet 12 is indicated by G2. In this way, the armature core 19 is attracted in the same direction as the radial component F3 in the resultant force of the pressing force from the two power supply brushes 22 by the attractive force of the magnet 12. Therefore, the armature shaft 17 to which the armature core 19 is fixed is also drawn together with the armature core 19 in the same direction as the radial component F3 of the combined force. Therefore, since the armature shaft 17 is pressed against the armature-side bearings 14a and 14b by the attractive force of the magnet 12, the posture of the armature shaft 17 is easily stabilized. As a result, the armature shaft 17 and the worm shaft 35 are easily maintained in a state in which the center axis lines L1 and L4 are arranged on a straight line, that is, in a state in which the axial deviation is suppressed.

  As shown in FIG. 5, by setting the width of the radial gap (air gap) between the armature core 19 and the magnet 12 to partially different values, the axis between the armature shaft 17 and the worm shaft 35 The shift may be suppressed. More specifically, in the motor shown in FIG. 5, the first and second armature side bearings 14a and 14b and the first and second worm side bearings 34a and 34b have straight center axes L6, L7, L2 and L3. It is arranged to be on the line. Further, a radial gap (air gap) between the armature core 19 and the magnet 12 is a pressing direction side (that is, a front side in the pressing direction) due to a radial component F3 of the resultant force of the pressing force of the two power supply brushes 22. The part on the opposite side to the pressing direction by the radial component F3 of the combined force (that is, the rear side in the pressing direction) is set to be narrower in the radial direction than the part. In FIG. 5, a gap between the armature core 19 on the pressing direction side by the radial component F3 and the magnet 12 is indicated by G3, and the armature core 19 on the opposite side to the pressing direction by the radial component F3 is shown. A gap between the magnet 12 and the magnet 12 is indicated by G4. In this way, the armature core 19 is attracted in the direction opposite to the radial component F3 of the combined force by the attractive force of the magnet 12. Therefore, the armature shaft 17 is restrained from moving in the direction of the radial component F3 of the resultant force of the pressing force from the two power supply brushes 22, and the central axis L1 of the armature shaft 17 is the distance between the pair of worm side bearings 34a and 34b. Deviation from the central axis L2, L3 (that is, the central axis L4 of the worm shaft 35) is suppressed. As a result, the axial deviation between the armature shaft 17 and the worm shaft 35 can be suppressed, and the generation of vibration and noise due to the axial deviation between the armature shaft 17 and the worm shaft 35 can be suppressed.

  In the above embodiment, the power supply brush 22 is urged toward the commutator 20 by the torsion coil spring 23. However, the biasing means for biasing the power supply brush 22 toward the commutator 20 is not limited to the torsion coil spring 23 but may be a compression coil spring or the like.

  In the above embodiment, the speed reduction mechanism 32 includes the worm shaft 35 and the worm wheel 39, but is not limited thereto as long as the configuration includes the worm shaft 35. For example, a gear may be further added after the worm wheel 39, and the output shaft 40 may be provided so as to be rotatable integrally with the gear.

The technical idea that can be grasped from the above embodiment and each of the above modifications will be described below.
(A) In the motor according to claim 1 or 2, the armature side bearing that pivotally supports an end of the armature shaft on the worm shaft side is made of an insulating resin material and holds the power supply brush. A motor which is held by a brush holder. According to this configuration, since the one armature side bearing is held by the brush holder made of a resin material, the position of the armature side bearing can be easily set.

  (B) In the motor according to any one of claims 1, 2, and (a), the pair of armature-side bearings is configured so that the commutator is pressed by the plurality of power supply brushes. The central axis of the armature side bearing is in a direction opposite to the radial component of the resultant force with respect to the central axis of the worm side bearing so that the central axis of the armature shaft and the central axis of the worm side bearing are aligned. A motor characterized by being offset. According to this configuration, when the commutator is pressed against a plurality of power supply brushes, the center axis of the armature shaft and the center axis of the pair of worm side bearings are in a straight line. Can be further suppressed, and the occurrence of vibrations and abnormal noise caused by the misalignment between the armature shaft and the worm shaft can be further suppressed.

  (C) In the motor according to any one of claims 1, 2, (A) and (B), the motor includes two power supply brushes, and the two power supply brushes include the commutator. The motor is disposed at an outer periphery of the armature so as to be separated by 90 ° in the rotation direction of the armature. According to this configuration, in a motor having two power supply brushes arranged 90 ° apart from each other in the rotation direction of the armature, axial misalignment between the armature shaft and the worm shaft can be suppressed. It is possible to suppress the occurrence of vibrations and abnormal noise caused by the axial deviation from the shaft.

  DESCRIPTION OF SYMBOLS 11 ... Yoke housing, 12 ... Magnet, 14a ... 1st armature side bearing as armature side bearing, 14b ... 2nd armature side bearing as armature side bearing, 16 ... Armature, 17 ... Armature shaft, 19 ... Armature core , 20 ... commutator, 22 ... power supply brush, 23 ... torsion coil spring as urging means, 32 ... reduction mechanism, 34a ... first worm side bearing as worm side bearing, 34b ... second worm as worm side bearing Side bearing, F3: radial component, L1: central axis of armature shaft, L2, L3: central axis of worm side bearing, L6, L7: central axis of armature side bearing.

Claims (3)

An armature having an armature shaft and a commutator fixed to the armature shaft;
A pair of armature-side bearings that support the armature shaft;
A plurality of power supply brushes arranged on the outer periphery of the commutator;
A plurality of biasing means for biasing each of the power supply brushes toward the commutator;
A decelerating mechanism having a worm shaft coupled to the armature shaft so as to be integrally rotatable, and decelerating the rotation of the armature shaft;
A motor including a pair of worm side bearings that support the worm shaft, wherein the resultant force of the pressing force by which the plurality of power supply brushes press the commutator does not become zero;
The pair of armature-side bearings are arranged such that their central axes are offset with respect to the central axis of the worm-side bearing in a direction opposite to the radial component of the resultant force. The motor according to claim 1,
A yoke housing that houses the armature therein;
A magnet fixed to the inner peripheral surface of the yoke housing;
The armature has an armature core made of a metal magnetic material fixed to the armature shaft and facing the magnet in the radial direction,
The gap between the armature core and the magnet is narrower at the portion on the pressing direction side due to the radial component of the resultant force than at the portion opposite to the pressing direction due to the radial component of the resultant force. Motor. A yoke housing;
A magnet fixed to the inner peripheral surface of the yoke housing;
An armature disposed inside the yoke housing and having an armature shaft, an armature core fixed to the armature shaft and facing the magnet in a radial direction, and a commutator fixed to the armature shaft;
A pair of armature-side bearings that support the armature shaft;
A plurality of power supply brushes arranged on the outer periphery of the commutator;
A plurality of biasing means for biasing each of the power supply brushes toward the commutator;
A decelerating mechanism having a worm shaft coupled to the armature shaft so as to be integrally rotatable, and decelerating the rotation of the armature shaft;
A motor including a pair of worm side bearings that support the worm shaft, wherein the resultant force of the pressing force by which the plurality of power supply brushes press the commutator does not become zero;
The armature-side bearing and the worm-side bearing are arranged so that their center axes are in a straight line,
The gap between the armature core and the magnet is narrower in a portion on the opposite side to the pressing direction due to the radial component of the resultant force than in a portion on the pressing direction side due to the radial component of the resultant force. Motor.

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