JP2013247702A - Motor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor device which allows for accurate reversal operation of a worm wheel within a narrow angular range while suppressing manufacturing cost increase.SOLUTION: A sensor magnet 53 is provided at a position offset from the center of rotation C of a worm wheel 52. An MR sensor 23b is provided at a position facing a sensor magnet 53 as the worm wheel 52 rotates relatively, within a projection range thereof in the axial direction of an output shaft 22. The MR sensor 23b can thereby be located at a position where the line of magnetic flux of the sensor magnet 53 is formed arcuately, as the worm wheel 52 rotates relatively. Within a narrow angular range of rotation of the worm wheel 52 less than 180° (within a range of 90° in the embodiment), the direction of line of magnetic flux crossing the MR sensor 23b can be changed from forward direction to reverse direction (180° reversal).

Description

  The present invention relates to a motor device including a motor unit having a rotation shaft and a gear unit having a worm wheel having a rotation shaft transmitted to the rotation shaft and provided with an output shaft at the center of rotation. The present invention relates to a motor device including a sensor magnet and a magnetic sensor for detecting a position.

  2. Description of the Related Art Conventionally, as a drive source for a wiper device, a power window device, or the like mounted on a vehicle such as an automobile, an electric motor (motor device) with a speed reduction mechanism that can output large power while being small is used. As such a motor device, for example, a technique described in Patent Document 1 is known. Hereinafter, the motor device (conventional technology) described in Patent Document 1 will be described with reference to FIG. FIG. 8 is an explanatory diagram for explaining the outline of a conventional motor device.

  As shown in FIG. 8, the electric motor (motor apparatus) a described in Patent Document 1 includes a motor part b and a speed reduction mechanism part (gear part) c. An armature shaft (rotating shaft) d is rotatably provided inside the motor portion b, and a worm e provided integrally with the armature shaft d and an output shaft f at the center of rotation are provided inside the speed reduction mechanism portion c. A provided worm wheel g is rotatably accommodated. Thereby, the rotation of the armature shaft d is transmitted to the output shaft f through the worm e and the worm wheel g. The worm e and the worm wheel g form a speed reduction mechanism h, which reduces the rotational speed of the armature shaft d to a predetermined speed, and outputs the rotation that is decelerated and increased in torque to the outside from the output shaft f. ing.

  A substantially disc-shaped sensor magnet i is fixed to the surface of the worm wheel g and at the center of rotation, and one side of the sensor magnet i in the radial direction is magnetized to the N pole, and the other side in the radial direction is magnetized to the S pole. It is magnetized by the north and south poles at 180 ° intervals along the circumferential direction of the magnet i. A control board j for controlling the rotation of the motor part b is provided inside the speed reduction mechanism part c, and a magnetic sensor k is provided at a part of the control board j facing the rotation center of the sensor magnet i. Yes.

  The magnetic sensor k detects the rotational position of the worm wheel g, that is, the rotational position of the output shaft f. Thereby, for example, when the electric motor a is used as the drive source of the wiper device, the position of the wiper blade relative to the windshield can be controlled by the control unit l provided on the control board j. Further, another magnetic sensor m is provided at a portion of the control board j facing the armature shaft d, and the magnetic sensor m faces the ring-shaped magnet n fixed to the armature shaft d, thereby controlling the control unit l. Can detect the number of rotations of the armature shaft d and the like to control the rotation speed of the electric motor a (the operation speed of the wiper device).

JP 2009-225520 A

  However, according to the electric motor a (see FIG. 8) described in Patent Document 1 described above, the following problems can occur. 9 is an explanatory diagram for explaining the positional relationship between the output shaft of the conventional motor device, the sensor magnet and the magnetic sensor, and the state of the magnetic flux lines, and FIGS. 10A and 10B are detection characteristics of the conventional magnetic sensor. The graph which shows is shown, respectively.

  As shown in FIG. 9, in the electric motor a, the center positions of the output shaft f, the sensor magnet i, and the magnetic sensor k are coaxially arranged along the axial direction of the output shaft f. Therefore, when the sensor magnet i rotates relative to the magnetic sensor k around the output shaft f and the sensor magnet i rotates 180 ° relative to the magnetic sensor k, the magnetic flux lines (from the N pole) cross the magnetic sensor k. The direction of the two-dot chain line arrow in the figure facing the S pole is reversed. Specifically, since the magnetic sensor k is arranged at a position where the magnetic flux lines are substantially straight from the N pole to the S pole, when the sensor magnet i rotates 180 ° with respect to the magnetic sensor k, the right side shown in FIG. The direction of the magnetic flux lines from one side to the left changes from the left side to the right side in the reverse direction.

  Accordingly, as shown in FIG. 10A, the magnetic flux density passing through the magnetic sensor k is minimized when the angle (rotational position) of the worm wheel g (output shaft f) is 0 °, 180 °, and 360 °. , 90 °, and 270 ° to change to a maximum. Here, as the magnetic sensor k, for example, an MR sensor is used, and the resistance value changes in accordance with the direction of the magnetic flux lines. Therefore, an electrical signal proportional to FIG. (Change in resistance value) is output. In other words, as shown in FIG. 10B, the electric motor a is configured such that the angle of the worm wheel g and the recognition angle of the magnetic sensor k change in a 1: 1 relationship.

  Therefore, when the conventional electric motor a is used as a drive source of a wiper device (direct drive wiper device) that directly swings and drives the wiper blade, the wiper blade is within a narrow range of 90 ° (narrow angle, for example). Since it is necessary to perform a reciprocating wiping operation within the range, as shown in FIG. 10A, the magnetic flux density is set within a range from 0 ° corresponding to the lower reversal position of the wiper blade to 90 ° corresponding to the upper reversal position. It is necessary to be able to detect with high accuracy. However, as shown in FIG. 10 (a), the magnetic flux density does not substantially change in the vicinity of 90 °. Therefore, the inexpensive magnetic sensor k has a low resolution, and it is difficult to detect the 90 ° position with high accuracy. Therefore, it is conceivable to use a high-precision and expensive magnetic sensor with high resolution. However, simply increasing the resolution of the magnetic sensor and controlling the electric motor a with high precision is practical because it greatly increases the manufacturing cost. is not. Therefore, it is desirable to fundamentally review the structure of the motor device so that it can handle the direct drive wiper device as described above by using as low-cost components as possible.

  An object of the present invention is to provide a motor device capable of accurately reversing a worm wheel within a narrow angle range while suppressing an increase in manufacturing cost.

  The motor device of the present invention is provided on the worm wheel, the motor unit having a rotating shaft, the gear unit having the worm wheel having the output shaft provided at the rotation center to which the rotation of the rotating shaft is transmitted, A motor device comprising: a sensor magnet that rotates together with a worm wheel; and a magnetic sensor that is provided to face the sensor magnet and outputs an electrical signal in accordance with relative rotation of the worm wheel, wherein the sensor magnet is The magnetic sensor is provided at a position eccentric from the rotation center of the worm wheel, the magnetic sensor is within a projection range of the worm wheel along the axial direction of the output shaft, and with the relative rotation of the worm wheel, It is provided in the position which opposes.

  The motor device according to the present invention is characterized in that the magnetic sensor is housed inside the gear portion and provided on a control board for controlling the rotation of the motor portion.

  The motor device according to the present invention is characterized in that the sensor magnet is provided on the worm wheel so that the N pole and the S pole face each other along a circumferential direction of the worm wheel.

  According to the motor device of the present invention, the sensor magnet is provided at a position decentered from the rotation center of the worm wheel, and the magnetic sensor is within the projection range of the worm wheel along the axial direction of the output shaft, and relative to the worm wheel. Since it is provided at a position facing the sensor magnet as it rotates, the magnetic sensor can be arranged at a position where the magnetic flux lines of the sensor magnet are formed in an arc shape according to the relative rotation of the worm wheel. This makes it possible to change the direction of the magnetic flux lines crossing the magnetic sensor from the normal direction to the reverse direction (180 ° inversion) within a narrow angle range where the rotation of the worm wheel is less than 180 °. Therefore, the rotation of the output shaft can be performed while using an inexpensive magnetic sensor without increasing the resolution, and the magnetic flux density passing through the magnetic sensor can be greatly changed within a narrow angle range where the rotation of the worm wheel is less than 180 °. The position can be detected with high accuracy. Therefore, the worm wheel can be accurately reversed within a narrow angle range while suppressing an increase in manufacturing cost.

  According to the motor device of the present invention, the magnetic sensor can be provided on the control board that is housed in the gear portion and controls the rotation of the motor portion. In addition, the sensor magnet can be provided on the worm wheel so that the N pole and the S pole face each other along the circumferential direction of the worm wheel.

It is explanatory drawing explaining the example of application to the direct drive wiper apparatus of the motor apparatus which concerns on this invention. It is explanatory drawing explaining the structure of the motor apparatus of FIG. (A), (b) is operation | movement explanatory drawing explaining operation | movement of the worm wheel of FIG. It is explanatory drawing explaining the positional relationship of the output shaft of the motor apparatus of FIG. 1, a sensor magnet, and a magnetic sensor, and the state of a magnetic flux line. It is explanatory drawing explaining the direction of the magnetic flux line which passes a magnetic sensor. (A), (b) is a graph which shows the detection characteristic of a magnetic sensor compared with the past. It is explanatory drawing explaining the structure of the motor apparatus which concerns on 2nd Embodiment. It is explanatory drawing explaining the outline | summary of the conventional motor apparatus. It is explanatory drawing explaining the positional relationship of the output shaft of a conventional motor apparatus, a sensor magnet, and a magnetic sensor, and the state of a magnetic flux line. (A), (b) is a graph which shows the detection characteristic of the conventional magnetic sensor.

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

  FIG. 1 is an explanatory diagram for explaining an application example of a motor device according to the present invention to a direct drive wiper device, FIG. 2 is an explanatory diagram for explaining the structure of the motor device of FIG. 1, and FIGS. ) Is an operation explanatory diagram for explaining the operation of the worm wheel of FIG. 2, FIG. 4 is an explanatory diagram for explaining the positional relationship of the output shaft, sensor magnet and magnetic sensor of the motor device of FIG. 5 is an explanatory diagram for explaining the direction of magnetic flux lines passing through the magnetic sensor, and FIGS. 6A and 6B are graphs showing the detection characteristics of the magnetic sensor in comparison with the conventional one.

  As shown in FIG. 1, a windshield 11 as a windshield is attached to the front side of a vehicle 10 such as an automobile, and rainwater or the like attached to the windshield 11 is attached to the lower end side of the windshield 11. A wiper device 12 is mounted to secure the driver's field of view. The wiper device 12 includes a DR wiper motor (motor device) 20 arranged on the driver's seat side (DR side) of the vehicle 10 and an AS side wiper motor (motor device) arranged on the passenger seat side (AS side) of the vehicle 10. 30, and the wiper motors 20 and 30 are configured in the same manner, and are disposed opposite to each other on the left and right sides of the vehicle 10.

  Each wiper motor 20, 30 has a DR-side wiper member 21 and an AS-side wiper member 31. The DR-side wiper member 21 includes a DR-side wiper arm 21a and a DR-side wiper blade 21b, and the AS-side wiper member 31 includes an AS-side wiper arm 31a and an AS-side wiper blade 31b. The base ends of the wiper arms 21a and 31a are fixed to the output shafts 22 and 32 of the wiper motors 20 and 30, respectively. The wiper motors 20 and 30 connect the wiper members 21 and 31 without using a link mechanism or the like. It is designed to directly swing. Thus, the wiper device 12 is a counter-wiping type direct drive wiper device.

  As shown in FIG. 1, each wiper blade 21b, 31b is driven to swing, that is, reciprocating wiping within a range of 90 ° (within a narrow angle range) between the lower inversion position LRP and the upper inversion position URP. It is like that. The wiper motors 20 and 30 detect the rotational positions of the output shafts 22 and 32 so that the wiper blades 21b and 31b are reversed at the lower reversal position LRP and the upper reversal position URP.

  In each wiper motor 20, 30, a DR-side control board 23 and an AS-side control board 33 are accommodated, and a communication line 13 is provided between the control boards 23, 33. That is, the wiper motors 20 and 30 communicate with each other via the communication line 13, and thus the rotational position information of the output shafts 22 and 32 (respective wiper blades 21 b and 31 b via the communication line 13. The position information) is communicated with each other, so that the wiper blades 21b and 31b can be reciprocated without collision on the windshield 11.

  A wiper switch 14 provided in the passenger compartment (not shown) is connected to the AS-side control board 33. By operating the wiper switch 14 by an operator, each of the wiper motors 20 and 30 has a high speed (High ), Low speed (Low) or intermittent (Int). As described above, in addition to the rotational position information described above, the rotational speed information of the wiper motors 20 and 30 and the like travel back and forth on the communication line 13.

  Next, the structure of each wiper motor 20, 30 will be described in detail with reference to the drawings. Since the DR-side wiper motor 20 and the AS-side wiper motor 30 are both configured in the same manner, the description of the AS-side wiper motor 30 will be omitted and the detailed structure of the DR-side wiper motor 20 will be described as a representative.

  As shown in FIG. 2, the DR-side wiper motor 20 has a motor unit 40 and a gear unit 50 connected to the motor unit 40. The motor unit 40 includes a yoke 41 formed into a bottomed cylindrical shape by pressing a steel plate made of a magnetic material, and a pair of permanent magnets 42 are mounted inside the yoke 41. Inside each permanent magnet 42, an armature 43 is rotatably provided through a predetermined gap (air gap), and a coil (not shown) is wound around the armature 43 in a predetermined winding method and number of turns. Has been.

  An armature shaft 44 as a rotation shaft is passed through and fixed to the rotation center of the armature 43, and the base end side (right side in the figure) of the armature shaft 44 is rotated to the bottom of the yoke 41 via a radial bearing (not shown). It is supported freely. Further, the distal end side (left side in the drawing) of the armature shaft 44 extends into the case 51 of the gear portion 50.

  A worm 45 is integrally formed on the distal end side of the armature shaft 44, and the worm 45 is meshed with a tooth portion 52 a of the worm wheel 52. Here, the worm 45 and the worm wheel 52 constitute a speed reduction mechanism SD. The speed reduction mechanism SD decelerates the rotation of the armature shaft 44 to increase the torque, and at the same time, rotates the increased torque to the worm wheel 52. Is output toward the DR-side wiper arm 21a (see FIG. 1) via the output shaft 22 fixed to the head.

  A commutator 46 is integrally provided at a position near the armature 43 of the armature shaft 44. The end of the coil is electrically connected to the commutator 46, and a pair of brushes 47 are in sliding contact. As a result, by supplying a drive current to each brush 47, a drive current flows through the coil via the commutator 46, an electromagnetic force is generated in the armature 43, and consequently the armature shaft 44 is moved in the forward or reverse direction. It rotates at a predetermined rotational speed.

  A worm wheel 52 is rotatably accommodated in the case 51 of the gear unit 50, and rotation from the worm 45 is transmitted to the worm wheel 52. The proximal end side of the output shaft 22 is fixed to the rotation center C1 of the worm wheel 52 so as to be integrally rotatable, and the distal end side of the output shaft 22 extends to the outside via a boss portion (not shown) of the case 51. It is connected to the DR side wiper arm 21a (see FIG. 1).

  A sensor magnet 53 (shaded portion in the figure) formed in a substantially disk shape is mounted on the front side surface 52b on the worm wheel 52, that is, the surface opposite to the side on which the output shaft 22 is fixed. The sensor magnet 53 uses a general-purpose sensor magnet similar to the conventional one, and rotates together with the worm wheel 52. One side along the radial direction of the sensor magnet 53 is magnetized to the N pole, and the other side along the radial direction of the sensor magnet 53 is magnetized to the S pole. That is, the sensor magnet 53 is magnetized to the N pole and the S pole (two poles) at intervals of 180 ° along the circumferential direction.

  The diameter dimension of the sensor magnet 53 is set to be approximately equal to the radial dimension of the worm wheel 52, and the sensor magnet 53 is eccentric (offset) from the rotation center C 1 of the worm wheel 52, that is, the rotation center C 1 of the output shaft 22. Is provided. Specifically, as shown in FIGS. 2 and 3, one end portion P of the boundary line 53 a dividing the N pole and the S pole formed at the center of the sensor magnet 53 is positioned at the rotation center C <b> 1 of the worm wheel 52. As such, the sensor magnet 53 is disposed within the radius range of the worm wheel 52. Thus, the boundary line 53a of the sensor magnet 53 extends in the radial direction of the worm wheel 52 around the rotation center C1 of the worm wheel 52, and the sensor magnet 53 is connected to the N pole along the circumferential direction of the worm wheel 52. The worm wheel 52 is provided so as to face the south pole.

  The gear portion 50 includes a cover member (not shown) that closes an opening portion (front side in the drawing) of the case 51. On the inner side of the cover member, a DR-side control board 23 (two-dot chain line in the figure, hereinafter simply referred to as the control board 23) is mounted so as to face the worm wheel 52. 50 is housed inside. The control board 23 controls the rotation of the motor unit 40. On the control board 23, in addition to a plurality of electronic components (not shown) such as transistors and resistors, a control unit comprising a CPU having RAM, ROM, etc. 23a is mounted. Further, one MR sensor (magnetoresistance element) 23b is mounted on a portion of the control board 23 facing the sensor magnet 53.

  In the present embodiment, the MR sensor 23 b is mounted at a predetermined position on the control board 23 accommodated in the gear portion 50. Therefore, the MR sensor 23b can be positioned at a normal position with respect to the sensor magnet 53 only by housing the control board 23 in the gear portion 50 and assembling the DR-side wiper motor 20, thereby simplifying the assembly procedure. . However, the MR sensor 23b is not limited to being mounted on the control board 23, and may be installed directly inside the cover member, for example.

  As shown in FIGS. 2 and 3, the MR sensor 23 b is provided within a projection range of the worm wheel 52 along the axial direction of the output shaft 22 and at a position facing the sensor magnet 53 with the relative rotation of the worm wheel 52. ing. Specifically, the MR sensor 23b is arranged between the rotation center C1 of the worm wheel 52 and the center C2 of the sensor magnet 53.

  In this manner, the MR sensor 23b is disposed between the rotation center C1 of the worm wheel 52 and the center C2 of the sensor magnet 53, and the sensor magnet 53 is connected to the N pole and the S pole along the circumferential direction of the worm wheel 52. By providing the worm wheel 52 so as to face each other, as shown in FIG. 4, the MR sensor 23b is arranged at a position where the magnetic flux lines (two-dot chain arrows in the figure) of the sensor magnet 53 are formed in an arc shape. Composed. Here, the MR sensor 23b constitutes a magnetic sensor in the present invention.

  The MR sensor 23b uses an inexpensive MR sensor similar to the conventional one, and the magnitude of the electrical signal (the amount of change in the resistance value) changes depending on the direction of the magnetic flux across itself (the previous value). See FIG. An electrical signal from the MR sensor 23b generated with the relative rotation of the sensor magnet 53 is sent to the control unit 23a, and the control unit 23a responds to the magnitude of the electrical signal from the MR sensor 23b. Thus, the rotational position of the worm wheel 52 with respect to the case 51, that is, the position of the DR-side wiper blade 21 b with respect to the windshield 11 is grasped, and the rotation of the DR-side wiper member 21 is performed by controlling the rotation of the motor unit 40 based on this. (See FIG. 1).

  Next, the operation of the DR-side wiper motor 20 formed as described above will be described in detail with reference to the drawings.

  When the wiper switch 14 is operated and the DR-side wiper motor 20 is rotationally driven, the output shaft 22 is shown by a broken line arrow within a narrow angle range of 90 ° as shown in FIGS. 3 (a) and 3 (b). The rotation in the FWD direction (forward direction) and the rotation in the broken line arrow REV direction (reverse direction) are repeated. Thereby, the DR-side wiper blade 21b performs a reciprocating wiping operation on the windshield 11 within a range of 90 °, and rainwater and the like adhering to the windshield 11 is wiped (see FIG. 1).

  The control unit 23a performs switching control of the rotation direction of the output shaft 22, that is, switching control of the wiping direction of the DR-side wiper blade 21b on the windshield 11, based on an electrical signal from the MR sensor 23b. For example, as shown in FIG. 3A, when the DR-side wiper blade 21b is at the upper reverse position URP (90 °), it is the switching timing for rotating the motor unit 40 in the reverse direction (return drive). The relative position of the MR sensor 23 b with respect to the sensor magnet 53 at that time is on the N pole of the sensor magnet 53. As shown in the right half of FIG. 5, the MR sensor 23b on the N pole has a magnetic flux line rotating at an angle of about 45 ° from the lower right side in the drawing toward the upper left side in the drawing. It crosses toward the center C1.

  On the other hand, as shown in FIG. 3B, when the DR-side wiper blade 21b is in the lower inversion position LRP (0 °), it is a switching timing for rotating the motor unit 40 forward (forward path driving). The relative position of the MR sensor 23 b with respect to the sensor magnet 53 at that time is on the S pole of the sensor magnet 53. Further, as shown in the left half of FIG. 5, the MR sensor 23b located on the S pole has a magnetic flux line at an angle of about 45 ° from the upper right side in the figure toward the lower left side in the figure. Crossing from C1.

  Thus, in the DR-side wiper motor 20, when the worm wheel 52 is rotated by 90 °, the direction of the magnetic flux lines crossing the MR sensor 23b is reversed by 180 °. Therefore, as shown by a solid line (present invention) in FIG. 6A, the magnetic flux density passing through the MR sensor 23b is such that the angle (rotational position) of the worm wheel 52 is 0 ° (lower inversion position LRP) and 90 ° (lower inversion position LRP). It changes to be minimum at the upper reversal position URP) and maximum at 45 ° which is the intermediate position. In addition, the broken line of Fig.6 (a) shows the same characteristic as the continuous line of Fig.10 (a), and represents the prior art.

  That is, the amount of change in the magnetic flux density increases in the vicinity of the position where the rotational position of the worm wheel 52 is 0 ° and 90 °, and the amount of change in the electrical signal from the MR sensor 23b also increases in proportion to this. This means that even with an inexpensive MR sensor 23b, the position where the rotation position of the worm wheel 52 is 0 ° and 90 ° (lower inversion position LRP / upper inversion position URP) can be accurately detected by the control unit 23a. I mean. As described above, in the DR-side wiper motor 20, as shown by the solid line (present invention) in FIG. 6B, the angle of the worm wheel 52 and the recognition angle of the MR sensor 23b change in a 1: 2 relationship. It has become. In addition, the broken line of FIG.6 (b) shows the same characteristic as the continuous line of FIG.10 (b), and represents the prior art.

  As described above in detail, according to the DR-side wiper motor 20 according to the present embodiment, the sensor magnet 53 is provided at a position eccentric from the rotation center C1 of the worm wheel 52, and the MR sensor 23b is provided on the output shaft 22. Since it is provided within the projection range of the worm wheel 52 along the axial direction and at a position facing the sensor magnet 53 with the relative rotation of the worm wheel 52, the magnetic flux lines of the sensor magnet 53 according to the relative rotation of the worm wheel 52. The MR sensor 23b can be arranged at a position where is formed in an arc shape.

  Thus, the rotation of the worm wheel 52 is within a narrow angle range of less than 180 ° (within the range of 90 ° in the present embodiment), and the direction of the magnetic flux lines crossing the MR sensor 23b is reversed from the normal direction (reversed by 180 °). ) Can be changed. Therefore, the magnetic flux density passing through the MR sensor 23b can be changed greatly within a narrow angle range of less than 180 ° (in the present embodiment, within the range of 90 °), thereby improving the resolution. Thus, the rotational position of the output shaft 22 can be detected with high accuracy while using the inexpensive MR sensor 23b without using an expensive magnetic sensor. Therefore, the worm wheel 52 can be accurately reversed within a narrow angle range while suppressing an increase in manufacturing cost.

  Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 7 is an explanatory diagram for explaining the structure of the motor device according to the second embodiment.

  As shown in FIG. 7, a ring-shaped multipolar magnet 48 (shaded portion in the figure) is fixed between the worm 45 and the commutator 46 of the armature shaft 44. It is formed by alternately magnetizing N poles, S poles... (For example, 6 poles) at equal intervals in the circumferential direction. The multi-pole magnet 48 is used for detecting the rotation speed, rotation direction, and the like of the armature shaft 44 together with the pair of hall sensors 23c, 23d mounted on the control board 23. Each Hall sensor 23c, 23d is mounted on the control board 23 facing the multipolar magnet 48 at a predetermined interval.

  In the second embodiment, the hall sensors 23c and 23d and the MR sensor 23b are mounted at predetermined positions on the control board 23 housed in the gear unit 50. Therefore, the hall sensors 23c and 23d and the MR sensor 23b can be positioned at the normal positions with respect to the multipolar magnet 48 and the sensor magnet 53 only by housing the control board 23 in the gear portion 50 and assembling the DR-side wiper motor 20. In this way, the assembly procedure is simplified. However, the hall sensors 23c and 23d and the MR sensor 23b are not limited to being mounted on the control board 23, and may be installed directly inside the cover member, for example.

  Each Hall sensor 23c, 23d generates a rectangular wave electric signal (pulse signal) with the rotation of the multipolar magnet 48, and these pulse signals are sent to the control unit 23a. And the control part 23a grasps | ascertains rotation conditions, such as the rotation speed of the armature axis | shaft 44, and a rotation direction, by counting the appearance timing and appearance number of each pulse signal, and controls rotation of the motor part 40 based on this. It has become.

  Also in the second embodiment formed as described above, the same effects as those in the first embodiment described above can be achieved. In addition to this, in the second embodiment, the control unit 23a grasps the rotation state of the armature shaft 44 such as the rotation speed and the rotation direction, so that the motor unit 40 can be controlled to rotate more accurately. .

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in each of the above embodiments, the MR sensor 23b is used as the magnetic sensor in the present invention. However, the present invention is not limited to this, and the rotation (movement) of the sensor magnet 53 is continuously detected. Other magnetic sensors such as a linear Hall sensor and a Hall sensor that can be used can also be used. In short, any rotation angle sensor that can detect the rotation angle by magnetism may be used.

  In each of the above embodiments, the MR sensor 23b is disposed between the rotation center C1 of the worm wheel 52 and the center C2 of the sensor magnet 53 (see FIGS. 2 and 7), and in a narrow angle range of 90 °. Although the reciprocating wiping operation of the DR-side wiper blade 21b is shown, the present invention is not limited to this, and the position of the MR sensor 23b is determined according to the specifications of the wiper device 12, for example, the rotation of the worm wheel 52 It may be arranged close to the center C1 or close to the center C2 of the sensor magnet 53, so that a narrow angle range (less than 180 °) of any size can be set. Further, the location where the MR sensor 23 b is disposed may not be between the rotation center C <b> 1 of the worm wheel 52 and the center C <b> 2 of the sensor magnet 53.

  Further, in each of the above embodiments, the sensor magnet 53 is disposed within the radius range of the worm wheel 52 so that the one end P of the boundary line 53a of the sensor magnet 53 is positioned at the rotation center C1 of the worm wheel 52. Although the present invention is not limited to this, according to the specifications of the wiper device 12, the sensor magnet 53 is moved from the state shown in FIGS. You may make it provide in the worm wheel 52 in the state rotated (for example, 15 degrees in the forward direction or 15 degrees in the reverse direction). Even in this case, a narrow angle range (less than 180 °) of any size can be set. Furthermore, although the diameter dimension of the sensor magnet 53 is set to a dimension substantially equal to the radial dimension of the worm wheel 52, the present invention is not limited to this, and the diameter dimension of the sensor magnet 53 is set to an arbitrary size. You may do it.

  Further, in each of the above-described embodiments, the DR-side wiper motor 20 of the wiper device 12 that wipes the windshield 11 of the vehicle 10 is applied to the present invention. However, the present invention is not limited to this, and the rear window of the vehicle 10 is not limited thereto. The present invention can also be applied to wiper motors used for wiping glass and windshields of railway vehicles and aircraft.

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Windshield 12 Wiper apparatus 13 Communication line 14 Wiper switch 20 DR side wiper motor (motor apparatus)
21 DR side wiper member 21a DR side wiper arm 21b DR side wiper blade 22 Output shaft 23 DR side control board (control board)
23a Control unit 23b MR sensor (magnetic sensor)
23c, 23d Hall sensor 30 AS wiper motor (motor device)
31 AS-side wiper member 31a AS-side wiper arm 31b AS-side wiper blade 32 Output shaft 33 AS-side control board (control board)
40 Motor part 41 Yoke 42 Permanent magnet 43 Armature 44 Armature shaft (rotating shaft)
45 Worm 46 Commutator 47 Brush 48 Multi-pole magnet 50 Gear 51 Case 52 Warm wheel 52a Tooth 52b Front side 53 Sensor magnet 53a Boundary line P One end C1 Center of rotation C2 Center SD Deceleration mechanism LRP Lower reverse position URP Upper reverse position a electric motor b motor part c reduction mechanism part d armature shaft e worm f output shaft g worm wheel h reduction mechanism i sensor magnet j control board k magnetic sensor l control unit m magnetic sensor n ring magnet

Claims (3)

A motor unit having a rotating shaft, a gear unit having a worm wheel that transmits rotation of the rotating shaft and having an output shaft at the center of rotation, and a sensor magnet that is provided on the worm wheel and rotates together with the worm wheel And a magnetic sensor that is provided to face the sensor magnet and outputs an electrical signal in accordance with relative rotation of the worm wheel,
The sensor magnet is provided at a position eccentric from the rotation center of the worm wheel,
The motor device according to claim 1, wherein the magnetic sensor is provided within a projection range of the worm wheel along the axial direction of the output shaft and at a position facing the sensor magnet as the worm wheel rotates relative thereto.   The motor device according to claim 1, wherein the magnetic sensor is housed inside the gear portion and provided on a control board for controlling the rotation of the motor portion.   3. The motor device according to claim 1, wherein the sensor magnet is provided on the worm wheel so that an N pole and an S pole face each other along a circumferential direction of the worm wheel.

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