JP2016039701A - Motor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor device in which a result of detection by a magnetic sensor is unlikely to be influenced by a relative assembly error of a sensor magnet and the magnetic sensor.SOLUTION: In a wiper motor, the magnetic sensor that is disposed on an axial line of an output shaft detects a change in a magnetic flux of a sensor magnet 36 that is rotated integrally with the output shaft. The sensor magnet 36 confronts the magnetic sensor 34 in an axial direction of the output shaft, and a center CE is positioned between an N pole 36A and an S pole 36B which are neighboring to each other in a radial direction of the output shaft. In a view in the axial direction of the output shaft, a dimension of the sensor magnet 36 in a magnetic axis orthogonal direction that is orthogonal with a magnetic axis direction is set equal to or larger than a dimension in the magnetic axis direction, and edges 36A1 and 36B1 in the N pole 36A and the S pole 36B at opposite sides to each other are formed so as to be separated from the center CE as turning from the side of a magnetic axis AX to both end sides in the magnetic axis orthogonal direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a magnetic sensor and a motor device including a sensor magnet.

  In the motor device described in Patent Document 1 below, the output shaft is supported so as to be rotatable with respect to the gear housing, and a worm wheel accommodated in the gear housing is coaxially connected to one end in the axial direction of the output shaft. Fixed. The worm wheel is rotated integrally with the output shaft by the rotational force of the motor body. A housing cover attached to the gear housing is provided on one side in the axial direction of the worm wheel, and an electronic circuit board is attached to the housing cover. A magnetic sensor for detecting the rotation angle of the output shaft is mounted on the electronic circuit board.

  The magnetic sensor described above is opposed to a sensor magnet attached to the axial center portion of one end surface in the axial direction of the worm wheel. This sensor magnet is formed in a circular shape when viewed from the axial direction of the worm wheel, one side in the radial direction is magnetized to the N pole, and the other side in the radial direction is magnetized to the S pole. A change in magnetic flux when the sensor magnet rotates together with the worm wheel is detected by the magnetic sensor, and the rotation angle of the output shaft is calculated based on the detection result. Based on the calculated rotation angle, the rotation speed, rotation stop position, reverse position, and the like of the output shaft are controlled. In Patent Document 2 below, a motor device similar to the above is described.

JP 2014-42431 A JP 2014-50309 A

  In the motor device as described above, when the circular sensor magnet is viewed from the magnetic sensor side, the magnetic flux is distributed in parallel from the N pole toward the S pole on the center side of the sensor magnet due to the characteristics of the magnetic field. However, as the sensor magnet is displaced in the radial direction from the center side, the magnetic flux distribution is widened by the repulsive force between the magnetic fluxes, and the curvature of the magnetic flux is increased.

  In the motor device as described above, the sensor magnet is supported on the gear housing via the worm wheel and the output shaft, while the magnetic sensor is attached to the gear housing via the electronic circuit board and the housing cover. For this reason, due to manufacturing variations, the relative assembly position of the sensor magnet and the magnetic sensor may be displaced in the radial direction of the sensor magnet.

  In such a case, the magnetic sensor facing the position displaced in the radial direction from the center side of the sensor magnet detects a magnetic flux having a large curvature of curvature as viewed from the magnetic sensor side, and based on the detection result. As the calculated rotation angle of the output shaft, an angular position different from the rotation angle that should be detected is calculated. The rotation angle obtained in this way affects the control of the rotation speed of the output shaft, the rotation stop position, the reverse position, and the like.

  In view of the above facts, an object of the present invention is to obtain a motor device in which a detection result by a magnetic sensor is not easily affected by a relative assembly error between a sensor magnet and a magnetic sensor.

  The motor device of the present invention includes an output shaft that is rotated by transmission of a rotational force of a motor body, a magnetic sensor that is disposed on one axial direction with respect to the output shaft, and that detects a change in magnetic flux, and the output shaft. Provided so as to be integrally rotatable, and opposed to the magnetic sensor in the axial direction of the output shaft, and the center of the outer shape is located between the N pole and the S pole adjacent in the radial direction of the output shaft, The dimension in the direction perpendicular to the magnetic axis direction perpendicular to the magnetic axis direction when viewed from the axial direction is set to be equal to or greater than the dimension in the magnetic axis direction, and the opposite edges of the N pole and the S pole are the magnetic poles. And a sensor magnet formed so as to move away from the center as it goes from the shaft side toward both ends in the direction perpendicular to the magnetic axis.

  In the motor device having the above configuration, the magnetic sensor arranged on one side in the axial direction with respect to the output shaft detects a change in the magnetic flux of the sensor magnet that rotates integrally with the output shaft. This sensor magnet faces the magnetic sensor in the axial direction of the output shaft, and the center of the outer shape (hereinafter simply referred to as the center) is located between the N pole and the S pole adjacent in the radial direction of the output shaft. positioned. When viewed from the axial direction of the output shaft, the sensor magnet has a dimension in the direction perpendicular to the magnetic axis perpendicular to the direction of the magnetic axis and is set to be equal to or greater than the dimension in the magnetic axis direction. The opposite edges of the sensor magnet are formed so as to move away from the center of the sensor magnet as they go from the magnetic axis side to both end sides in the direction perpendicular to the magnetic axis. Thereby, when the sensor magnet is viewed from the magnetic sensor side arranged on one side in the axial direction with respect to the output shaft, the curvature of the curvature of the magnetic flux increases as it shifts from the center side in the radial direction of the output shaft. This can be suppressed as compared with a conventional circular sensor magnet. As a result, even when a relative assembly error occurs between the sensor magnet and the magnetic sensor, the magnetic sensor can prevent or suppress the magnetic sensor from detecting a magnetic flux having a large curvature when viewed from the magnetic sensor side. Therefore, it is possible to obtain a correct detection result in which the detection result obtained by is less affected by the relative assembly error between the sensor magnet and the magnetic sensor.

  In the motor device of the present invention, in addition to the above-described configuration, at least an intermediate portion of the magnetic pole orthogonal direction extends linearly in the magnetic axis orthogonal direction at the end edges of the N pole and the S pole. ing.

  In the motor device configured as described above, the opposite edges of the N and S poles of the sensor magnet are formed as described above, so that the curvature of the curvature is small or not curved when viewed from the magnetic sensor side. The magnetic flux distribution region can be expanded in the direction perpendicular to the magnetic axis.

  Further, in the motor device of the present invention, in addition to the above configuration, the sensor magnet is integrally provided with the N pole and the S pole, and the surface of the sensor magnet on the magnetic sensor side has the N pole. A concave portion is formed by denting a portion straddling the pole and the S pole to the side opposite to the magnetic sensor.

  In the motor device having the above configuration, since the concave portion is formed in the sensor magnet, it is possible to suppress the magnetic flux distribution from spreading in the axial direction of the output shaft on the boundary side between the N pole and the S pole.

  Furthermore, in the motor device of the present invention, in addition to the above-described configuration, the sensor magnet is configured by a pair of magnets arranged with a gap in the magnetic axis direction, and the one of the magnets is provided with the sensor magnet. The N pole and the S pole provided on the other magnet face each other with the gap therebetween.

  In the motor device having the above configuration, the N pole provided in one magnet constituting the sensor magnet and the S pole provided in the other magnet are opposed to each other with a gap. For this reason, magnetic flux can be distributed in parallel or substantially in parallel over a wide range of the gap.

  In the motor device according to the present invention, in addition to the above-described configuration, the sensor magnet is configured such that the N pole and the S pole are integrally coupled via a non-magnetized region, and the sensor magnet in the non-magnetized region is The width dimension in the magnetic axis direction decreases from the magnetic axis side toward both end sides in the magnetic axis orthogonal direction.

  In the motor device having the above configuration, since the width dimension of the non-magnetized region of the sensor magnet is set as described above, the edge on the non-magnetized region side of the N pole and the S pole is magnetized from the magnetic axis side. It curves or inclines so that it may mutually approach, so that it goes to the both ends side of an axis orthogonal direction. Thereby, the curvature of magnetic flux can be suppressed by the property of the magnetic flux (line of magnetic force) which is going to enter and exit perpendicularly to the edge of each magnetic pole. In other words, the magnetic flux distributed across the non-magnetized region tends to repel each other and spread from the magnetic axis side toward both ends of the magnetic axis orthogonal direction. Tilt to counter the repulsion. Thereby, the distribution area of the magnetic flux having a small curvature or not curved as viewed from the magnetic sensor side can be expanded.

  In the motor device according to the present invention, in addition to the above-described configuration, a rotating body is coaxially fixed to the output shaft, and the magnetic sensor is an electron opposed to and spaced from one end surface in the axial direction of the rotating body. The rotating body is attached to the circuit board, and the rotating body holds the sensor magnet by a plurality of holding pieces extended from the one axial end surface to the electronic circuit board side, and the plurality of holding pieces and the A gap through which the sensor magnet cannot pass is formed between the electronic circuit board.

  In the motor device configured as described above, the sensor magnet is held by the rotating body by a plurality of holding pieces extending from one end surface in the axial direction of the rotating body. A gap through which the sensor magnet cannot pass is formed between the plurality of holding pieces and the electronic circuit board on which the magnetic sensor is attached. For this reason, even if the holding of the sensor magnet by a plurality of holding pieces is released for some reason such as an impact applied to the motor device, the sensor magnet is prevented from dropping through the gap. Or it can be suppressed.

  In the motor device of the present invention, a wiper arm fixing portion to which a wiper arm of a vehicle wiper device is fixed is provided at a tip portion of the output shaft.

  In the motor device configured as described above, since the wiper arm is directly fixed to the wiper arm fixing portion provided at the tip of the output shaft, the rotation angles of the output shaft and the wiper arm are equal. In this respect, in the present invention, as described above, the detection result of the magnetic sensor is not easily affected by the relative assembly error between the sensor magnet and the magnetic sensor, so that the rotation angle of the output shaft, that is, the wiper arm can be accurately detected. It becomes possible.

1 is a perspective view of a motor device according to a first embodiment of the present invention. It is a side view of the motor device, and shows a state in which a part of the motor device is broken. It is a perspective view which shows the state which abbreviate | omitted the housing cover in the motor apparatus. It is a perspective view which shows the state which abbreviate | omitted a part of gear housing in the motor apparatus. The sensor magnet which is a structural member of the motor apparatus is shown, (A) is a perspective view, (B) is a plan view, and (C) is a side view. It is the enlarged view to which a part of FIG. 3 was expanded. It is the enlarged view to which a part of FIG. 2 was expanded. It is a conceptual diagram for demonstrating that the magnetic flux which comes out from a north pole and enters into a south pole tries to advance by the shortest distance. It is a conceptual diagram for demonstrating that distribution of magnetic flux spreads when magnetic flux mutually repels. It is a conceptual diagram for demonstrating the principle which suppresses the breadth of distribution of magnetic flux in the sensor magnet which concerns on 1st Embodiment. It is a conceptual diagram for demonstrating distribution of the magnetic flux in the conventional circular sensor magnet. It is a figure for demonstrating the measurement area | region of the magnetic flux in the magnetic sensor with respect to a circular sensor magnet. It is a figure for demonstrating the measurement area | region of the magnetic flux in the magnetic sensor with respect to a substantially rectangular sensor magnet. It is the graph which compared the direction of the magnetic flux in the position OP with respect to a magnetic-axis direction in a substantially rectangular sensor magnet and a circular sensor magnet. The sensor magnet which concerns on 2nd Embodiment of this invention is shown, (A) is a perspective view, (B) is a top view, (C) is a side view. The sensor magnet which concerns on 3rd Embodiment of this invention is shown, (A) is a perspective view, (B) is a top view, (C) is a side view. The sensor magnet which concerns on 4th Embodiment of this invention is shown, (A) is a perspective view, (B) is a top view, (C) is a side view. It is a perspective view which shows the modification of the sensor magnet which concerns on 4th Embodiment. The sensor magnet which concerns on 5th Embodiment of this invention is shown, (A) is a perspective view, (B) is a top view, (C) is a side view. It is a conceptual diagram for demonstrating distribution of the magnetic flux of the sensor magnet which concerns on 5th Embodiment. It is a top view which shows the sensor magnet which concerns on 6th Embodiment of this invention, and is the figure which attached | subjected the dot to the non-magnetized area | region. It is a top view which shows the conventional circular sensor magnet, and is the figure which attached | subjected the dot to the non-magnetized area | region. It is explanatory drawing for demonstrating the structure of the magnetizer of a sensor magnet. It is a conceptual diagram for demonstrating the principle which suppresses the breadth of distribution of magnetic flux in the sensor magnet which concerns on 6th Embodiment.

<First Embodiment>
Hereinafter, the wiper motor 10 as the motor device according to the first embodiment of the present invention will be described with reference to FIGS. First, the overall configuration of the wiper motor 10 will be described, and then the main part of the present embodiment will be described.

(Overall configuration of wiper motor 10)
A wiper motor 10 according to the present embodiment is a drive source of a vehicle wiper device, and as shown in FIGS. 1 to 4, a motor body 12, a metal gear housing 14, and a resin housing cover 16. It has. The housing cover 16 is fixed to the gear housing 14 by a plurality of screws 18 (see FIGS. 2 and 4).

  The motor body 12 is attached to a side portion of the gear housing 14, and the armature shaft 20 extends into the gear housing 14. A bearing 22 that pivotally supports the tip of the armature shaft 20 is provided at the end of the gear housing 14 opposite to the motor body 12. A worm gear 20A is formed by means such as rolling at a portion of the armature shaft 20 located in the gear housing 14. The worm gear 20 </ b> A meshes with a worm wheel 24 as a rotating body housed in the gear housing 14.

  The worm wheel 24 is made of resin here, and a bottomed cylindrical boss portion 24 </ b> A is coaxially formed at the center thereof. A plurality of ribs 24B are formed radially around the boss portion 24A on the outer side in the radial direction of the boss portion 24A. A metal output shaft 26 is coaxially fixed to the boss portion 24A. The output shaft 26 is insert-molded when the worm wheel 24 is molded, and a base end portion that is one end portion in the axial direction is fixed to the worm wheel 24 and protrudes from the worm wheel 24 to the other side in the axial direction. ing.

  The gear housing 14 is formed with an output shaft support portion 14A corresponding to the output shaft 26 described above. The output shaft support portion 14A is formed in a cylindrical shape coaxial with the output shaft 26 and the worm wheel 24, and is directed from the gear housing 14 to the other axial side of the output shaft 26 (the side opposite to the housing cover 16). Projecting together. The output shaft 26 is inserted inside the output shaft support portion 14A, and is rotatably supported by the output shaft support portion 14A via a pair of bearings (not shown) attached inside the output shaft support portion 14A. ing.

  The distal end portion of the output shaft 26 protrudes from the opening on the distal end side of the output shaft support portion 14A to the outside of the gear housing 14, and a tea washer 28 is fastened to the protruding portion. The output shaft 26 is prevented from being pulled out by the tea washer 28.

  The worm wheel 24 fixed to the base end portion of the output shaft 26 is meshed with the worm gear 20A of the armature shaft 20 as described above. For this reason, when the motor body 12 is actuated to rotate the armature shaft 20, this rotational force is transmitted to the worm wheel 24 via the worm gear 20 </ b> A, and the worm wheel 24 rotates integrally with the output shaft 26.

  A wiper arm fixing portion 26 </ b> A is provided at the distal end portion of the output shaft 26. The wiper arm fixing portion 26A is configured to directly fix a base end portion 30A (see a two-dot chain line in FIG. 2) of the wiper arm 30 that is a constituent member of the vehicle wiper device.

  Further, a plurality (three in this case) of vehicle body side fixing portions 14B are provided around the output shaft support portion 14A of the gear housing 14, and bolts or the like are provided on the female screw portions formed on the vehicle body side fixing portion 14B. The wiper motor 10 is fixed to a bracket (not shown), and the bracket is fixed to a cowl top or the like of the vehicle.

  Then, the wiper arm 30 fixed to the wiper arm fixing portion 26A is rotated integrally with the output shaft 26, whereby the wiper blade connected to the distal end side of the wiper arm 30 is windshield glass of the vehicle (both not shown). Wipe away. The wiper arm 30 is not limited to being directly fixed to the output shaft 26, and the wiper arm 30 may be indirectly connected to the output shaft 26 via a pivot shaft, a link mechanism, or the like.

  On the other hand, as shown in FIG. 2, an electronic circuit board 32 is disposed on one side of the worm wheel 24 in the axial direction (the side opposite to the direction in which the output shaft 26 protrudes). The electronic circuit board 32 is fixed to the inner surface side of the housing cover 16 by a plurality of screws 33 (see FIG. 4), and the thickness direction is along the axial direction of the output shaft 26 and one end surface of the worm wheel 24 in the axial direction. Are arranged in a state of facing each other with a space therebetween. A magnetic sensor 34 is mounted on the electronic circuit board 32.

  The magnetic sensor 34 is disposed so as to be spaced apart in one axial direction with respect to the output shaft 26, and the output shaft 26 has an axial direction one end surface (one axial end surface of the boss portion 24 </ b> A) of the output shaft 26. Opposite the axial direction. A sensor magnet 36 is attached to one end surface in the axial direction of the boss portion 24 </ b> A so as to be coaxial with the output shaft 26. The sensor magnet 36 can rotate integrally with the worm wheel 24 and the output shaft 26, and faces the magnetic sensor 34 in the axial direction of the output shaft 26.

  The magnetic sensor 34 is configured such that the output voltage changes in accordance with changes in the magnetic flux of the sensor magnet 36 (changes in the direction of magnetic flux, magnetic flux density, etc.), and the relative rotation angle of the sensor magnet 36 with respect to the magnetic sensor 34. Accordingly, the output voltage of the magnetic sensor 34 changes. The magnetic sensor 34 is a Hall IC in the present embodiment, but is not limited thereto, and the magnetic sensor 34 may be configured using a magnetoresistive element, a Hall element, an MRIC, or the like. The electronic circuit board 32 is provided with control means such as an ECU, and the control means calculates the rotation angle of the sensor magnet 36 based on the change in the output voltage of the magnetic sensor 34.

  The rotation angle of the sensor magnet 36 matches the rotation angle of the worm wheel 24 and the output shaft 26. In addition, this rotation angle also coincides with the rotation angle of the wiper arm 30 in this embodiment. Therefore, the control means is configured to control the rotation speed, rotation stop position, reversal position, and the like of the output shaft 26, that is, the wiper arm 30, based on the output voltage of the magnetic sensor 34. The above is the overall configuration of the wiper motor 10 according to the present embodiment. Hereinafter, the sensor magnet 36 which is a main part of the present embodiment and the configuration around it will be described.

(Main part of this embodiment)
The sensor magnet 36 is formed, for example, by mixing a binder made of synthetic resin or the like and magnetic powder and molding the molded product. As shown in FIGS. 5A to 5C, the sensor magnet 36 is formed in a substantially rectangular plate shape with four corners chamfered in an arc shape, and the axis of the output shaft 26. The direction is arranged with the plate thickness direction (see FIGS. 2 and 3).

  This sensor magnet 36 has one half in the width direction (arrow X direction in FIG. 5B) magnetized to the N pole 36A, the other half in the width direction magnetized to the S pole 36B, and NS2 poles. The magnetic poles are integrated. The N pole 36 </ b> A and the S pole 36 </ b> B are adjacent to each other in the radial direction of the output shaft 26. As shown in FIG. 5B, the sensor magnet 36 has an outer center CE set at the center in the longitudinal direction (arrow Y direction) and at the center in the width direction (arrow X direction). The center CE is located on the magnetic axis AX of the sensor magnet 36 between the N pole 36A and the S pole 36B. This sensor magnet 36 has a magnetic axis orthogonal direction (arrow Y direction: hereinafter referred to as orthogonal to the magnetic axis direction (arrow X direction) when viewed from the axial direction of the output shaft 26 (direction perpendicular to the paper surface in FIG. 5B). The dimension of the “magnetic axis orthogonal direction” is set longer than the dimension of the magnetic axis direction. 5A to 5C, for convenience of explanation, the boundary BL between the N pole 36A and the S pole 36B is indicated by a one-dot chain line.

  Further, as shown in FIG. 5B, the opposite end edges 36A1 and 36B1 of the N pole 36A and the S pole 36B are located in the direction perpendicular to the magnetic axis. It extends parallel and straight. FIG. 5B shows a virtual circle VC centered on the center CE and tangent to the edges 36A1 and 36B1. The edges 36A1 and 36B1 are formed from the magnetic axis AX side. It forms so that it may leave | separate from the virtual circle VC, so that it goes to the both ends side of an axis orthogonal direction. That is, when viewed from the axial direction of the output shaft 26, these end edges 36A1 and 36B1 are formed so as to be separated from the center CE of the sensor magnet 36 as it goes from the magnetic axis AX side to both end sides in the magnetic axis orthogonal direction. ing.

  As shown in FIGS. 3, 6, and 7, the sensor magnet 36 configured as described above has a plurality of holding pieces 38, 40, and 42 that extend from one end surface in the axial direction of the boss portion 24A to the electronic circuit board 32 side. (The worm wheel 24 is schematically shown in FIG. 7). These holding pieces 38, 40, 42 are arranged along the outer periphery of the sensor magnet 36 so as to surround the sensor magnet 36.

  Specifically, the holding pieces 38 are arranged on both sides of the sensor magnet 36 in the direction perpendicular to the magnetic axis (longitudinal direction). Further, holding pieces 40 and holding pieces 42 are arranged side by side in the longitudinal direction of the sensor magnet 36 on both sides in the magnetic axis direction (width direction) of the sensor magnet 36. A holding piece 40 located on one side in the width direction of the sensor magnet 36 and a holding piece 42 located on the other side in the width direction of the sensor magnet 36 face each other in the width direction of the sensor magnet 36. A holding piece 40 located on the other side in the width direction and a holding piece 42 located on one side in the width direction of the sensor magnet 36 face each other in the width direction of the sensor magnet 36. These holding pieces 38, 40, 42 are positioned with respect to the worm wheel 24 in contact with the outer peripheral surface of the sensor magnet 36.

  Further, as shown in FIG. 6, claw portions 42 </ b> A that protrude toward the sensor magnet 36 are formed at the tip portions of the holding pieces 42 that are respectively arranged on both sides in the width direction of the sensor magnet 36. These claw portions 42A engage with one side surface in the axial direction of the sensor magnet 36 (the surface opposite to the boss portion 24A), whereby the sensor magnet 36 is held by the worm wheel 24.

  As described above, the sensor magnet 36 held by the worm wheel 24 faces the magnetic sensor 34 in the axial direction of the output shaft 26, and rotates relative to the magnetic sensor 34 together with the worm wheel 24 and the output shaft 26. To do. In the present embodiment, the center CE of the sensor magnet 36 and the center of the magnetic sensor 34 are both designed to be located on the axis of the output shaft 26.

  Further, in the present embodiment, as shown in FIGS. 6 and 7, the holding pieces 38 and 40 are set to have a protruding height from the boss portion 24 </ b> A higher than the holding piece 42. A gap 46 is formed between the holding pieces 38 and 40 and the electronic circuit board 32 as shown in FIG. 7, and the holding pieces 38 and 40 and the electronic circuit board 32 are rotated when the worm wheel 24 is rotated. It is designed not to interfere. However, the dimension h of the gap 46 along the axial direction of the output shaft 26 is set smaller than the thickness dimension t of the sensor magnet 36. For this reason, the sensor magnet 36 is not allowed to pass through the gap 46.

  In addition, the shape of the holding piece for holding (attaching) the sensor magnet 36 to the worm wheel 24 is not limited to the shape of the holding pieces 38, 40, 42, and can be changed as appropriate. Further, the method of attaching the sensor magnet 36 to the worm wheel 24 is not limited to using the holding piece as described above, and other methods such as heat caulking and adhesion may be used.

(Function and effect)
Next, the operation and effect of this embodiment will be described.

  In the wiper motor 10 configured as described above, the magnetic sensor 34 disposed on one side in the axial direction with respect to the output shaft 26 detects a change in magnetic flux of the sensor magnet 36 that rotates integrally with the output shaft 26. The sensor magnet 36 faces the magnetic sensor 34 in the axial direction of the output shaft 26, and the center CE of the outer shape is located between the N pole 36 A and the S pole 36 B adjacent in the radial direction of the output shaft 26. doing. When viewed from the axial direction of the output shaft 26, the sensor magnet 36 is set so that the dimension in the direction perpendicular to the magnetic axis is perpendicular to the dimension in the magnetic axis, and the N pole 36A and the S pole Edges 36A1 and 36B1 opposite to each other on 36B are formed so as to be away from the center CE toward the both end sides in the direction perpendicular to the magnetic axis from the magnetic axis AX side.

  Thereby, when the sensor magnet 36 is viewed from the side of the magnetic sensor 34 disposed on one side in the axial direction with respect to the output shaft 26, the magnetic flux is curved as it is shifted from the center CE side in the radial direction of the output shaft 26. This can be suppressed as compared with a conventional circular sensor magnet. As a result, even when a relative assembly error occurs between the sensor magnet 36 and the magnetic sensor 34, the magnetic sensor 34 can be prevented or suppressed from detecting a magnetic flux having a large curvature when viewed from the magnetic sensor side. As a result of detection by the magnetic sensor 34, it is possible to obtain a correct detection result that is hardly affected by the relative assembly error between the sensor magnet 36 and the magnetic sensor 34.

  The above effect will be described based on the principle of the magnet with reference to FIGS. As shown in FIG. 8, the magnetic flux (line of magnetic force) that exits from the N pole and enters the S pole tends to travel in the shortest distance. However, since the magnetic flux can be simulated as a series of extremely small magnets, and adjacent magnetic fluxes (lines of magnetic force) repel each other, as shown in FIG. It spreads. As shown in FIG. 9, the magnetic flux (line of magnetic force) passing through the center CE between the N pole and the S pole (on the magnetic axis) is on both sides (upper and lower sides in FIG. 9) in the direction perpendicular to the magnetic axis. The balance is small because the repulsive force is received from the magnetic flux and balance is reduced. However, as the magnetic head moves away from the center CE in the direction perpendicular to the magnetic axis, the distribution of the magnetic flux is widened by the repulsive force between the magnetic fluxes, and the curvature of the magnetic flux is increased.

  Based on the above principle, as shown in FIG. 10, in the magnet in which the N pole and the S pole are adjacent to each other, the dimension in the direction perpendicular to the magnetic axis perpendicular to the magnetic axis direction (the dimension in the direction of arrow L in FIG. 10). ) Is infinitely long, the repulsive force between the magnetic fluxes balances in the intermediate part in the direction perpendicular to the magnetic axis (the intermediate part in the longitudinal direction of the magnet), and the distribution of the magnetic flux does not spread.

  On the other hand, in the conventional circular sensor magnet 100 as shown in FIG. 11, when the circular sensor magnet 100 is viewed from the axial direction, the magnetic flux is distributed in parallel on the center CE side. As the distance increases, the magnetic flux distribution increases and the curvature of the magnetic flux increases.

  For this reason, in the motor apparatus described in the background section, when the assembly position of the circular sensor magnet and the magnetic sensor is shifted in the radial direction of the output shaft, the magnetic flux having a large curvature when viewed from the magnetic sensor side. Therefore, the rotation angle of the output shaft calculated based on the detection result may be calculated as a rotation angle different from the rotation angle that should be detected. Such detection of the rotation angle affects the control of the rotation speed, rotation stop position, reverse position, and the like of the output shaft. For this reason, for example, in the configuration in which the opposed wiper arms are driven by two motors, the rotation angle of the output shaft of the wiper motor is detected as a position different from the original angle. There is a risk of damage due to interference. For example, when applied to a configuration in which tandem wiper arms are driven by two motors, interference between the wiper blade and the A-pillar may occur in the same manner. The above problem is particularly likely to occur in a so-called direct drive system in which the wiper arm is directly fixed to the output shaft, but may also occur in a wiper system in which the wiper arm is driven via a link mechanism or the like.

  In contrast, in the present embodiment, based on the principle of the magnet as described above, the shape of the sensor magnet 36 is changed from a conventional circular shape to a substantially rectangular shape that is long in a direction orthogonal to the polarization direction (magnetic axis direction) of the magnetic pole. ing. In the sensor magnet 36, the sensor magnet 36 is elongated in a direction orthogonal to the magnetic axis direction, and the opposite edges 36A1 and 36B1 of the N pole 36A and the S pole 36B extend linearly in the orthogonal direction. ing. This effectively suppresses the spread of the magnetic flux distribution at a position shifted in the radial direction of the output shaft 26 from the center CE of the sensor magnet 36 (in a shape in which the curvature of the magnetic flux as viewed from the magnetic sensor side is reduced). doing. As a result, it is possible to prevent the output shaft 26, that is, the wiper arm 30 from rotating at a rotational speed, a rotation stop position, and a reversal position, thereby preventing the interference between the wiper blades and the interference between the wiper blade and the A pillar as described above. At the same time, the feeling of operation of the vehicle wiper device can be improved.

  In the wiper system using two motors, the distance and angle between the wiper blades that are secured to prevent interference between the wiper blades, and the rotation angle of the wiper arm 36 in this embodiment are affected by the assembly error. By making difficult and accurate detection, the distance and angle secured for preventing interference can be set small.

  The effect of suppressing the spread of the magnetic flux distribution as described above in the present embodiment has been confirmed by a simulation comparison between the circular sensor magnet shown in FIG. 12 and the substantially rectangular sensor magnet shown in FIG. That is, the direction (angle) of the magnetic flux with respect to the magnetic axis direction at an arbitrary distance from the center CE in the circular sensor magnet shown in FIG. 12 and the center CE in the substantially rectangular sensor magnet shown in FIG. The direction (angle) of the magnetic flux with respect to the magnetic axis direction at the position OP that is a distance away was compared by simulation. As a result, as shown in FIG. 14, in the substantially rectangular sensor magnet, the direction (angle) of the magnetic flux with respect to the magnetic axis direction is smaller than that of the circular sensor magnet (facing the direction along the magnetic axis direction). It was confirmed that the spread of the magnetic flux distribution was suppressed (see arrow D in FIG. 14).

  In the present embodiment, the sensor magnet 36 is held on the worm wheel 24 by a plurality of holding pieces 38, 40, 42 extending from one end surface in the axial direction of the worm wheel 24. A gap 46 through which the sensor magnet 36 cannot pass is formed between the holding pieces 38 and 40 and the electronic circuit board 32 to which the magnetic sensor 34 is attached. For this reason, even if the holding of the sensor magnet 36 by the plurality of holding pieces 38, 40, 42 is released due to some reason such as an impact applied to the wiper motor 10, the sensor magnet 36 remains in the gap 46. It can be prevented or suppressed from falling off.

  Next, another embodiment of the present invention will be described. In addition, about the structure and effect | action similar to the said 1st Embodiment, the same code | symbol as the said 1st Embodiment is provided, and the description is abbreviate | omitted.

<Second Embodiment>
15A to 15C show a sensor magnet 50 according to a second embodiment of the present invention. The sensor magnet 50 is formed in a substantially oval (oval) plate shape, and the axial direction of the output shaft 26 (not shown in FIGS. 15A to 15C) is the plate thickness direction. The worm wheel 24 is attached to one end face in the axial direction of the boss portion 24A (not shown in FIGS. 15A to 15C).

  The sensor magnet 50 is integrally provided with an N pole 50A and an S pole 50B that are adjacent to each other in the radial direction of the output shaft 26. When viewed from the axial direction of the output shaft 26, the sensor magnet 50 (FIG. 15B ) In the direction perpendicular to the magnetic axis (in the direction of arrow Y in FIG. 15B).

  Further, the opposite end edges 50A1 and 50B1 of the N pole 50A and the S pole 50B have intermediate portions extending in a direction perpendicular to the magnetic axis and extending linearly in a direction perpendicular to the magnetic axis. And these edge 50A1, 50B1 is formed so that it may leave | separate from the center CE of the sensor magnet 50, so that it may go to the both ends side of a magnetic-axis orthogonal direction from the magnetic-axis AX side. Other configurations are the same as those in the first embodiment.

  In this embodiment as well, when the sensor magnet 50 is viewed from the magnetic sensor 34 side, the curvature of the magnetic flux increases as the radius of the output shaft 26 deviates from the center CE side. It can be suppressed compared to the case.

<Third Embodiment>
FIGS. 16A to 16C show a sensor magnet 60 according to a third embodiment of the present invention. The sensor magnet 60 is formed in a substantially square plate shape with four corners chamfered in an arc shape, and the axial direction of the output shaft 26 (not shown in FIGS. 16A to 16C). Is attached to one end face in the axial direction of the boss portion 24A of the worm wheel 24 (not shown in FIGS. 16A to 16C).

  The sensor magnet 60 is integrally provided with an N pole 60A and an S pole 60B that are adjacent to each other in the radial direction of the output shaft 26. When viewed from the axial direction of the output shaft 26, the sensor magnet 60 has a dimension in the magnetic axis direction (arrow X direction in FIG. 16B) and a magnetic axis orthogonal direction (FIG. The dimension in the direction of arrow Y in B) is set to be equivalent.

  Further, the opposite ends 60A1 and 60B1 of the N pole 60A and the S pole 60B have portions excluding both ends in the direction perpendicular to the magnetic axis extending in a straight line parallel to the direction perpendicular to the magnetic axis. And these edge 60A1, 60B1 is formed so that it may leave | separate from the center CE of the sensor magnet 60, so that it may go to the both ends side of a magnetic-axis orthogonal direction from the magnetic-axis AX side.

  Further, on the surface of the sensor magnet 60 on the side of the magnetic sensor 34 (the surface on the front side in FIG. 16B), a portion straddling the N pole 60A and the S pole 60B is recessed to the opposite side of the magnetic sensor 34. A shallow groove-like recess 62 is formed. The recess 62 is formed from one end to the other end of the sensor magnet 60 in the direction perpendicular to the magnetic axis, and the dimension in the magnetic axis direction is set to, for example, about half the width dimension of the sensor magnet 60. Other configurations are the same as those in the first embodiment.

  In this embodiment as well, when the sensor magnet 60 is viewed from the magnetic sensor 34 side, the curvature of the magnetic flux increases as the radial direction of the output shaft 26 shifts from the center CE side. It can be suppressed compared to the case. In addition, in the sensor magnet 60, the concave portion 62 is formed, so that the distribution of magnetic flux on the boundary BL side between the N pole 60A and the S pole 60B is in the axial direction of the output shaft 26 (in FIG. 16B). Spreading in a direction perpendicular to the paper surface) can be suppressed.

<Fourth Embodiment>
FIGS. 17A to 17C show a sensor magnet 70 according to a fourth embodiment of the present invention. The sensor magnet 70 has basically the same configuration as the sensor magnet 60 according to the third embodiment, but the configuration of the recess 72 is different from the recess 62 according to the third embodiment. The recess 72 is formed so that the thickness dimension of the sensor magnet 70 is gradually reduced from both end edges 70A1 and 70B1 in the width direction of the sensor magnet 70 toward the boundary BL between the N pole 70A and the S pole 70B. Also in this embodiment, the same effect as the third embodiment can be obtained. Note that, as in the sensor magnet 70 ′ shown in FIG. 18, the recess 72 may be formed only in the center portion in the width direction of the sensor magnet 70.

<Fifth Embodiment>
19A to 19C show a sensor magnet 80 according to a fifth embodiment of the present invention. The sensor magnet 80 includes a pair of magnets 82 and 84 that are adjacent to each other in the radial direction of the output shaft 26. These magnets 82 and 84 are formed in a substantially rectangular plate shape whose four corners are chamfered in an arc shape, and the output shaft 26 (not shown in FIGS. 19A to 19C). The boss portion 24A of the worm wheel 24 in a state where the axial direction is the plate thickness direction and is arranged in parallel with the gap 86 in the radial direction of the output shaft 26 (not shown in FIGS. 19A to 19C) Is attached to one end face in the axial direction.

  Each of the magnets 82 and 84 is magnetized on the N poles 82A and 84A on one side in the width direction (arrow X direction in FIG. 19B), and is magnetized on the S poles 82B and 84B on the other half in the width direction. Has been. The N pole 82A of one magnet 82 and the S pole 84B of the other magnet 84 face each other with the gap 86 therebetween (adjacent in the radial direction of the output shaft 26). The sensor magnet 80 is arranged so that the magnetic axes AX of the pair of magnets 82 and 84 coincide.

  In this sensor magnet 80, the center CE of the outer shape formed by the pair of magnets 82 and 84 is located at the center between the pair of magnets 82 and 84 and at the center in the longitudinal direction of the pair of magnets 82 and 84. . The N pole 82A of one magnet 82 and the S pole 84B of the other magnet 84 are adjacent to each other in the radial direction of the output shaft 26 via the center CE. Further, the opposite edges 82A1 and 84B1 of the N pole 82A and the S pole 84B are separated from the center CE of the sensor magnet 80 toward the both ends of the magnetic axis orthogonal direction from the magnetic axis AX side (virtual circle VC). Formed away from). Other configurations are the same as those in the first embodiment.

  Also in this embodiment, when the sensor magnet 80 is viewed from the magnetic sensor 34 side, the curvature of the magnetic flux increases as the radius of the output shaft 26 deviates from the center CE side. It can be suppressed compared to the case. In addition, in this embodiment, the N pole 82A of one magnet 82 and the S pole 84B of the other magnet 84 are adjacent to each other with a gap 86 in which the center CE of the sensor magnet 80 is set. Although the sensor magnets 82 and 84 are small, magnetic fluxes that are parallel or substantially parallel when viewed from the magnetic sensor 34 side can be distributed over a wide range of the gap 86 (see FIG. 20).

<Sixth Embodiment>
FIG. 21 shows a sensor magnet 90 according to a sixth embodiment of the present invention. The sensor magnet 90 has the same shape as the sensor magnet 36 according to the first embodiment, but is not attached to the boundary portion between the N pole 90A and the S pole 90B for manufacturing reasons. A magnetic region exists. In the non-magnetized region 90C, the width dimension in the magnetic axis direction (arrow X direction in FIG. 21) becomes smaller from the magnetic axis AX toward both ends in the magnetic axis orthogonal direction (arrow Y direction in FIG. 21). .

  As shown in FIG. 22, even in the conventional circular sensor magnet 100, a non-magnetized region 100C exists between the N pole 100A and the S pole 100B. This is because of the structural reason between the portion 102A for magnetizing the N pole 100A and the portion 102B for magnetizing the S pole 100B in the magnetizer 102 (see FIG. 23) for magnetizing the sensor magnet 100. This is because the gap 104 exists. Further, as shown in FIG. 22, in the conventional circular sensor magnet 100, the width dimension of the non-magnetized region 100C along the magnetic axis direction (the arrow X direction in FIG. 22) is set to be constant.

  That is, in the present embodiment, in the sensor magnet 90 in which the N pole 90A and the S pole 90B are integrally coupled via the non-magnetized region 90C, the shape of the magnetizer that magnetizes the sensor magnet 90 is processed. Thus, the non-magnetized region 90C is configured to swell toward the N pole 90A side and the S pole 90B side toward the center CE side of the sensor magnet 90. In FIGS. 21 to 23, for convenience of explanation, the non-magnetized regions 90C and 100C are marked with dots. Further, in FIG. 21, the parts denoted by reference numerals 90A1 and 90B1 are the opposite edges of the N pole 90A side and the S pole 90B. Other configurations are the same as those in the first embodiment.

  Also in this embodiment, since the sensor magnet 90 is set in the same shape as the sensor magnet 36 according to the first embodiment, it is possible to obtain the same function and effect as in the first embodiment. Moreover, in this embodiment, since the non-magnetized region 90C is set in the sensor magnet 90 as described above, the end of the N-pole 90A and the S-pole 90B on the non-magnetized region 90C side is the magnetic axis AX. Curved or inclined (curved here) so as to approach each other from the side toward both sides in the direction perpendicular to the magnetic axis. Thereby, the curvature of magnetic flux can be suppressed by the property of the magnetic flux (line of magnetic force) which is going to enter / exit perpendicularly to the end edges of the N pole 90A and the S pole 90B. That is, the magnetic flux (line of magnetic force) distributed across the non-magnetized region 90C tends to repel each other and spread toward the both end sides in the direction perpendicular to the magnetic axis (see FIG. 24A). However, in this embodiment, the direction of the magnetic flux with respect to each of the magnetic poles 90A and 90B is inclined in advance in consideration of the above-mentioned repulsion. (See FIG. 24B). Thereby, the distribution area of the magnetic flux having a small curvature or not curved as viewed from the magnetic sensor 34 side can be expanded.

<Supplementary explanation of the embodiment>
In the first to fourth and sixth embodiments, the sensor magnets 36, 50, 60, 70, 90 are configured to be formed in a substantially rectangular, substantially oval, or substantially square plate shape. The shape is not limited to these. For example, the sensor magnet may be formed in an elliptical plate shape.

  Further, in each of the above embodiments, a so-called “bonded magnet” that is formed by mixing a ferromagnetic powder and a binder made of a synthetic resin material is applied as the sensor magnet 36, but the present invention is not limited thereto, A sensor magnet formed by sintering a magnetic material may be used.

  In each of the above embodiments, the case where the rotating body is the worm wheel 24 has been described. However, the present invention is not limited thereto, and other types of gears such as a spur gear may be configured as the rotating body. .

  Moreover, although each said embodiment demonstrated the case where the motor apparatus was the wiper motor 10, not only this but this invention is applicable with respect to the various motor apparatuses mounted in a vehicle etc.

  In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to the above embodiments.

  DESCRIPTION OF SYMBOLS 10 ... Wiper motor (motor apparatus), 12 ... Motor main body, 24 ... Worm wheel (rotary body), 26 ... Output shaft, 26B ... Wiper arm fixing | fixed part, 30 ... Wiper arm, 32 ... Electronic circuit board, 34 ... Magnetic sensor, 36 ... Sensor magnet, 36A ... N pole, 36A1 ... Edge, 36B ... S pole, 36B1, 38, 40, 42 ..Holding piece, 50 ... sensor magnet, 50A ... N pole, 50A1 ... edge, 50B ... S pole, 50B1 ... edge, 60 ... sensor magnet, 60A ...・ N pole, 60A1 ... edge, 60B ... S pole, 60B1 ... edge, 62 ... concave, 70 ... sensor magnet, 70A ... N pole, 70A1 ... edge Edge, 70B ... S pole, 70B1 ... End , 72... Recess, 70 '... Sensor magnet, 80... Sensor magnet, 82... Magnet, 82A... N pole, 82A1. ... Magnet, 84A ... N pole, 84B ... S pole, 84B1 ... Edge, 86 ... Gap, 90 ... Sensor magnet, 90A ... N pole, 90A1 ... Edge, 90B ... S pole, 90B1, ... Edge, 90C ... Non-magnetized region, AX ... Magnetic axis, CE ... Center

Claims (7)

An output shaft that is rotated by the rotational force of the motor body, and
A magnetic sensor disposed on one axial direction with respect to the output shaft and detecting a change in magnetic flux;
The output shaft is provided so as to be rotatable integrally with the output shaft, and is opposed to the magnetic sensor in the axial direction of the output shaft. The dimension of the magnetic axis orthogonal direction that is positioned and orthogonal to the magnetic axis direction when viewed from the axial direction is set to be equal to or greater than the dimension of the magnetic axis direction, and the opposite edges of the N pole and the S pole Is a sensor magnet that is formed so as to move away from the center as it goes from the magnetic axis side to both end sides of the magnetic axis orthogonal direction,
A motor device comprising:   2. The motor device according to claim 1, wherein at least an intermediate portion in the direction perpendicular to the magnetic axis extends linearly in the direction perpendicular to the magnetic axis.   The sensor magnet is integrally provided with the N pole and the S pole, and a portion of the sensor magnet on the side of the magnetic sensor that extends between the N pole and the S pole is the magnetic sensor. The motor device according to claim 1, wherein a recess that is recessed toward the opposite side is formed. The sensor magnet is composed of a pair of magnets arranged with a gap in the magnetic axis direction,
The motor device according to claim 1, wherein the N pole provided in one of the magnets and the S pole provided in the other magnet are opposed to each other with the gap therebetween.   In the sensor magnet, the N pole and the S pole are integrally coupled via a non-magnetized region, and a width dimension in the magnetic axis direction in the non-magnetized region is determined from the magnetic axis side. The motor device according to claim 1, wherein the motor device is smaller toward both ends in the direction perpendicular to the axis. A rotating body is coaxially fixed to the output shaft,
The magnetic sensor is attached to an electronic circuit board opposed to and spaced from one end surface in the axial direction of the rotating body,
The rotating body holds the sensor magnet by a plurality of holding pieces extended from the one axial end surface to the electronic circuit board side,
The motor device according to claim 1, wherein a gap through which the sensor magnet cannot pass is formed between the plurality of holding pieces and the electronic circuit board.   The motor device according to any one of claims 1 to 6, wherein a wiper arm fixing portion to which a wiper arm of a vehicle wiper device is fixed is provided at a tip portion of the output shaft.

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