Wiper motor and wiper device

Abstract

To detect the rotational position of an output shaft without providing a circuit board in a housing.SOLUTION: A wiper motor 14 constituting a wiper device 10 includes an output shaft 26 displacing a wiper member 18, a gear wheel 46 rotating together with the output shaft 26, a housing 38 supporting the output shaft 26 and storing the gear wheel 46, and a magnet 52 fixed to the gear wheel 46. The wiper motor 14 also includes a choke coil 54 that includes a core 56 formed in a rod shape using a magnetic material, and a coil 58 formed around the core 56, with one axial direction end portion of the core 56 provided facing the magnet 52. The wiper motor 14 is also supported by the housing 38, and includes signal terminals 60, 62 connected to the coil 58.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a wiper motor and a wiper device. [Background technology]

[0002] Patent Document 1 listed below discloses a wiper motor (electric motor with a reduction mechanism) that detects the position of its output shaft. The wiper motor described in this document has a drive gear that rotates integrally with the output shaft, and this drive gear is disposed in a housing (casing). A magnet is fixed to the drive gear, and the magnetic force of this magnet is detected by a Hall IC fixed to a circuit board, making it possible to detect the position of the output shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-262515 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the wiper motor described in Patent Document 1, it is necessary to provide a circuit board to which the Hall IC and the like are fixed inside the housing, which hinders miniaturization of the wiper motor.

[0005] In consideration of the above, an object of the present disclosure is to provide a wiper motor and a wiper device that can detect the rotational position of an output shaft without providing a circuit board inside a housing. [Means for solving the problem]

[0006] The wiper motor (14) that solves the above problem includes an output shaft (26) connected to a wiper member (18) that wipes the windshield glass (12) of a vehicle and displaces the wiper member by rotating, a gear wheel (46) that rotates together with the output shaft, a housing (38) that supports the output shaft and accommodates the gear wheel, a magnet (52, 96) fixed to the gear wheel, a core (56) formed in a rod shape using a magnetic material, and a coil (58) formed around the core, with one axial end of the core facing the magnet side, a detection unit (54), and signal terminals (60, 62) supported by the housing and to which the coil is connected. In addition, a wiper device (10) that solves the above problem includes the wiper motor, the wiper member connected to the output shaft, and a control unit (20) that controls the operation and stopping of the wiper motor, and the control unit stops the wiper motor when it detects a signal indicating the stop of the wiper motor and when it detects that the induced electromotive force generated in the coil has reached a predetermined value.

[0007] With this configuration, the rotational position of the output shaft can be detected without providing a circuit board inside the housing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a wiper device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a partially cutaway front view of the wiper motor. [Figure 3] FIG. 2 is a side view showing a part of the wiper motor in section. [Figure 4] FIG. 2 is a perspective view showing a gear wheel and the like arranged in a gear housing. [Figure 5] FIG. [Figure 6] FIG. 2 is a perspective view showing a cover attached to a gear housing, with a portion of the cover cut away; [Figure 7]FIG. 2 is a block diagram schematically illustrating the wiper device, showing a state in which the wiper motor is stopped. [Figure 8] FIG. [Figure 9] FIG. 2 is a block diagram schematically illustrating the wiper device, showing a state in which the wiper motor is operating. [Figure 10] FIG. 10 is a view of a cover of a wiper motor of another embodiment as seen from the inside. [Figure 11] FIG. 2 is a perspective view showing a gear wheel and the like arranged in a gear housing. [Figure 12] FIG. 2 is a perspective view showing a gear wheel and the like arranged in a gear housing. [Figure 13] FIG. 10 is a waveform diagram showing the induced electromotive force of the choke coil generated with respect to the rotation angle of the gear wheel. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1, a wiper device 10 of this embodiment is for wiping a windshield glass 12 (for example, a front windshield glass) of a vehicle. The wiper device 10 includes a wiper motor 14, a link mechanism 16, a pair of left and right wiper members 18, and a control unit 20 that controls the wiper motor 14. Each of the left and right wiper members 18 includes a wiper arm 22 and a wiper blade 24 connected to the tip of the wiper arm 22.

[0010] As an example, the wiper motor 14 is a wiper motor of a type that rotates an output shaft 26 in one direction about its axis. One end of a crank arm 28, which is a component of a link mechanism 16, is fixed to the output shaft 26 of the wiper motor 14. The link mechanism 16 has a pair of left and right pivot shafts 30 to which base ends of the pair of left and right wiper arms 22 are respectively fixed, a pair of left and right pivot levers 32 each having one end fixed to the pair of left and right pivot shafts 30, a first link rod 34 suspended between one of the pivot levers 32 and the crank arm 28, and a second link rod 36 suspended between the other ends of the left and right pivot levers 32.

[0011] In the wiper device 10 of this embodiment, when the crank arm 28 rotates (continuously rotates) in one direction around the axis of the output shaft 26 of the wiper motor 14, the rotational drive force of the crank arm 28 is transmitted to one of the pivot levers 32 via the first link rod 34. The rotational drive force of this pivot lever 32 is transmitted to the other pivot lever 32 via the second link rod 36, causing the left and right pivot levers 32 to rotate back and forth around the axes of the left and right pivot shafts 30 together with the left and right pivot levers 32. As a result, the left and right wiper members 18 rotate back and forth in the same direction on the windshield glass 12 in unison, and the left and right wiper blades 24 wipe the windshield glass 12 in a reciprocating manner. In this case, each wiper member 18 rotates back and forth between a lower reversal position P1 and an upper reversal position P2. The left and right wiper members 18 are normally located at the lower reversal position P1 when the wiper motor 14 is not operating.

[0012] 2 and 3, the wiper motor 14 includes a housing 38, a stator 40 of the motor body fixed to the housing 38, and a rotor 42 rotatably supported by the housing 38 and the stator 40. The wiper motor 14 also includes a worm 44 provided on the rotor 42, a gear wheel 46 meshing with the worm 44, and an output shaft 26 fixed to the rotation center of the gear wheel 46.

[0013] As shown in Figures 3 and 4, the housing 38 is configured to include, for example, a housing main body 48 formed using a metal material such as an aluminum alloy, and a cover 50 formed using a highly insulating material such as a resin material.

[0014] The housing main body 48 is open on the gear wheel 46 and worm 44 side and includes a gear storage section 48A that stores the gear wheel 46 and worm 44. Gear teeth are formed on an outer peripheral portion 46A of the gear wheel 46 on the radially outer side, and these gear teeth mesh with the worm 44. One end of the output shaft 26 is embedded and fixed in a center portion 46B on the radially inner side of the gear wheel 46. Furthermore, a middle portion of the gear wheel 46 in the radial direction forms a connecting portion 46C that connects the outer peripheral portion 46A and the center portion 46B of the gear wheel 46 in the radial direction. This connecting portion 46C is formed in a disk shape with its thickness direction aligned with the rotational axis of the gear wheel 46. The portion of the center portion 46B of the gear wheel 46 on the cover 50 side is formed in a cylindrical shape that protrudes toward the cover 50 relative to the connecting portion 46C.

[0015] The housing main body 48 also includes an output shaft support portion 48B through which the other side of the output shaft 26 is inserted and which rotatably supports the output shaft 26. When the gear wheel 46 is stored in the gear storage portion 48A and the output shaft 26 is supported by the output shaft support portion 48B, the other end of the output shaft 26 (the end opposite the gear wheel 46) protrudes outside the housing main body 48.

[0016] The cover 50 is attached to the housing main body 48 from the side opposite to the output shaft support portion 48B. When the cover 50 is attached to the housing main body 48, the open end of the gear storage portion 48A is closed by the cover 50. The cover 50 also supports various terminals, which will be described later, and is provided with a single connector portion 50A to which a connector (not shown) is connected.

[0017] As shown in FIGS. 4, 5 and 6, the wiper motor 14 includes a magnet 52 for detecting the rotational position of the output shaft 26 and a choke coil 54 as a detection unit.

[0018] The magnet 52 is polarized in the axial direction and formed in a cylindrical shape, with at least one magnetic pole exposed. The axial dimension of the magnet 52 is set to be smaller than the radial dimension. The magnet 52 is fixed to the cover 50 side of the connection portion 46C with its axial direction facing the axial direction of the gear wheel 46. The magnet 52 is located near the center portion 46B of the connection portion 46C.

[0019] The choke coil 54 includes a core 56 formed in a rod shape using a magnetic material such as ferrite, and a coil 58 formed around the core.

[0020] The core 56 is formed in a cylindrical shape, and its axial dimension is set to be larger than its radial dimension. In this embodiment, the cross section of the core 56 taken in a direction perpendicular to the axial direction is circular, but it may have other cross-sectional shapes, such as a polygonal shape.

[0021] The coil 58 is formed by winding an electric wire such as a copper wire in a spiral shape around the outer periphery of the core 56. Both terminals of the coil 58 are directly connected to a first signal terminal 60 and a second signal terminal 62, respectively, supported by the cover 50. As a result, the choke coil 54 is supported in a predetermined position by the cover 50 via the first signal terminal 60 and the second signal terminal 62. Furthermore, since the coil 58 is directly connected to the first signal terminal 60 and the second signal terminal 62 provided on the connector part 50A described below, there is no need to provide a separate terminal for electrical routing from the connector part 50A to the coil 58.

[0022] The cover 50, with the choke coil 54 supported, is then attached to the housing main body 48, whereby the choke coil 54 is disposed in a predetermined position and orientation within the space between the cover 50 and the housing main body 48. In this embodiment, the axial direction of the core 56 is oriented in the axial direction of the output shaft 26 and the gear wheel 46. More preferably, the axis of the output shaft 26 and the axial direction of the core 56 are set parallel to each other. The core 56 is also located on the same circumference as the portion of the gear wheel 46 to which the magnet 52 is fixed. This allows the core 56 and the magnet 52 to face each other with a small axial gap between them when one axial end of the core 56 and the magnet 52 are closest to each other. Note that in Figures 5 and 6, a portion of the cover 50 is cut away to illustrate the attachment state of the choke coil 54 disposed within the space between the cover 50 and the housing main body 48.

[0023] 7 and 8, an external connector connected to the control unit 20 is connected to the connector portion 50A of the cover 50. This connector portion 50A is provided with a terminal portion of a first signal terminal 60 and a terminal portion of a second signal terminal 62 to which both terminal portions of the coil 58 are directly connected, a terminal portion of a first power supply terminal 64 and a terminal portion of a second power supply terminal 66 to which power is supplied, and a terminal portion of a ground terminal 68 connected to ground.

[0024] 7 to 9, the stator 40 and rotor 42 (see FIG. 2) that constitute a part of the wiper motor 14, as an example, constitute a part of a brushed DC motor 70. A first brush 72 and a second brush 74 of this DC motor 70 are connected to a second relay 90 (described later) via a first power supply terminal 64 and a second power supply terminal 66. A third brush 76 of the DC motor 70 is connected to the ground via a ground terminal 68. Note that a noise-reducing capacitor 78, a coil 80, and a circuit breaker 82 such as a thermistor are provided in the circuit that constitutes the wiper motor 14.

[0025] The control unit 20 controls the operation and stop of the wiper motor 14 and includes a CPU (Central Processing Unit) 84, a noise filter 86 (or amplifier AMP), a first relay 88, and a second relay 90. The coil 58 of the choke coil 54 is connected to the CPU 84 via the noise filter 86. A wiper switch 92 for selecting operation and stop of the wiper motor 14 is also connected to the CPU 84. The first relay 88 and the second relay 90 are so-called c-contact relays. The common terminals of the first relay 88 and the second relay 90 are connected to each other. The normally closed terminal of the first relay 88 is connected to ground, and the normally open terminal of the first relay 88 is connected to the vehicle battery 94. The normally closed terminal of the second relay 90 is connected to the second power supply terminal 66, and the normally open terminal of the second relay 90 is connected to the first power supply terminal 64.

[0026] (Actions and Effects of This Embodiment) Next, the operation and effects of this embodiment will be described.

[0027] As shown in FIGS. 1, 2, 6, and 9, when the control unit 20 detects a signal instructing the wiper motor 14 to rotate at a low speed by operating the wiper switch 92, the control unit 20 energizes the first relay 88 and the second relay 90, turning both relays ON. This causes power to be supplied from the battery 94 to the DC motor 70 via the first relay 88, the second relay 90, the first power terminal 64, and the like, causing the rotor 42 of the DC motor 70 to rotate. The rotation of the rotor 42 is reduced in speed and transmitted to the output shaft 26 via the worm 44 and the gear wheel 46. This causes the output shaft 26 to rotate at a rotational speed determined as the low-speed rotation. As a result, each wiper member 18 reciprocates between the lower reversal position P1 and the upper reversal position P2 at a low speed. When the control unit 20 detects a signal instructing the wiper motor 14 to rotate at high speed by operating the wiper switch 92, the control unit 20 turns the first relay 88 ON and the second relay 90 OFF. As a result, power is supplied from the battery 94 to the DC motor 70 via the first relay 88, the second relay 90, the second power supply terminal 66, etc., and the rotor 42 of the DC motor 70 rotates at high speed. As a result, the output shaft 26 rotates at a rotation speed determined as high speed rotation.

[0028] Here, the output shaft 26 rotates at the same rotation speed as the gearwheel 46. Therefore, while the output shaft 26 is rotating, the magnet 52 fixed to the gearwheel 46 repeatedly approaches and moves away from the core 56 of the choke coil 54. This causes an induced electromotive force to be generated in the coil 58 of the choke coil 54. This induced electromotive force has a needle-like waveform that reaches a peak value when the magnet 52, rotating with the gearwheel 46, is closest to the core 56 of the choke coil 54 (see FIG. 13). The induced electromotive force generated in the coil 58 is detected by the control unit 20. Here, in this embodiment, the magnet 52 is set to be closest to the core 56 of the choke coil 54 when each wiper member 18 is located at the lower reversal position P1.

[0029] When the control unit 20 detects a signal instructing the wiper motor 14 to stop rotating due to operation of the wiper switch 92, the control unit 20 turns off the first relay 88 as shown in FIG. 7 when the induced electromotive force in the coil 58 of the choke coil 54 reaches a predetermined value—here, when the control unit 20 detects that the induced electromotive force in the coil 58 exceeds a predetermined value near the peak value. This stops the power supply from the battery 94 to the DC motor 70, and both the positive and negative brushes of the DC motor 70 are connected to ground, forming a closed loop and applying dynamic braking. As a result, the rotation of the output shaft 26 of the wiper motor 14 stops near the position where the magnet 52 is closest to the core 56 of the choke coil 54. That is, each wiper member 18 stops at the lower reversal position P1.

[0030] In the wiper motor 14 of the present embodiment described above, the predetermined rotational position of the output shaft 26 can be detected by the choke coil 54 disposed within the housing 38. In this manner, the present embodiment makes it unnecessary to provide, within the housing 38, a circuit board that constitutes part of the circuit for detecting the predetermined rotational position of the output shaft 26. As a result, the size of the housing 38 is prevented from increasing, and the wiper motor 14 can be made smaller.

[0031] Furthermore, in this embodiment, the choke coil 54 is disposed within the housing 38 with the axial direction of the core 56 oriented in the axial direction of the output shaft 26. In this configuration, compared to a configuration in which the axial direction of the core 56 is oriented in a direction different from the axial direction of the output shaft 26, it is possible to reduce the space within the housing 38 in which the choke coil 54 is disposed in the radial direction of the output shaft 26.

[0032] 8, in this embodiment, the connector portion 50A of the cover 50 is provided with a terminal portion of a first signal terminal 60 and a terminal portion of a second signal terminal 62 to which both terminal portions of the coil 58 are respectively connected, a terminal portion of a first power supply terminal 64 and a terminal portion of a second power supply terminal 66 to which power is supplied, and a terminal portion of a ground terminal 68 connected to ground. In this configuration, the wiring work between the wiper motor 14 and the control unit 20 can be completed by connecting one connector to the connector portion 50A. In addition, in this embodiment, the configuration of the cover 50 (housing 38) can be prevented from becoming complicated compared to a configuration in which a connector portion for supplying power and a connector portion for detecting the induced electromotive force of the choke coil 54 are provided separately and independently.

[0033] 6, in this embodiment, the cover 50 supporting the choke coil 54 is attached to the housing main body 48, so that the choke coil 54 is disposed at a predetermined position and orientation in the space between the cover 50 and the housing main body 48. With this configuration, it is not necessary to provide the housing main body 48 with a portion for supporting the choke coil 54.

[0034] 4 and 6, in this embodiment, the magnet 52 is fixed to the gear wheel 46 while being positioned closer to the center 46B at the connection portion 46C. This configuration can prevent grease and the like used to lubricate the gear wheel 46 and the worm 44 from adhering to the magnet 52, compared to a configuration in which the magnet 52 is fixed to the gear wheel 46 while being positioned closer to the outer periphery 46A at the connection portion 46C.

[0035] In the present embodiment, an example has been described in which the magnet 52 is fixed to the gear wheel 46 while being positioned closer to the center 46B at the connection portion 46C, but the present invention is not limited to this. For example, in a configuration in which grease or the like used to lubricate the gear wheel 46 and the worm 44 is less likely to adhere to the magnet 52, it is also possible to employ a configuration in which the magnet 52 is fixed to the gear wheel 46 while being positioned closer to the outer circumferential portion 46A at the connection portion 46C.

[0036] Furthermore, in the present embodiment, an example has been described in which the cover 50 supporting the choke coil 54 is attached to the housing main body 48, thereby disposing the choke coil 54 at a predetermined position and orientation in the space between the cover 50 and the housing main body 48, but the present invention is not limited to this. For example, the choke coil 54 may be supported by the housing main body 48 so that the choke coil 54 is disposed in a predetermined position and orientation in the space between the cover 50 and the housing main body 48 without contacting the magnet 52.

[0037] In addition, in the present embodiment, an example has been described in which the wiring work between the wiper motor 14 and the control unit 20 can be completed by connecting one connector to the connector unit 50A, but the present invention is not limited to this. For example, depending on the configuration of the control unit 20 of the vehicle, a configuration can be adopted in which a connector unit for supplying power and a connector unit for detecting the induced electromotive force of the choke coil 54 are provided separately and independently.

[0038] Furthermore, in the present embodiment, an example has been described in which the choke coil 54 is disposed within the housing 38 with the axial direction of the core 56 oriented in the axial direction of the output shaft 26, but the present invention is not limited to this. For example, as shown in FIGS. 10 and 11 , a configuration may be employed in which the choke coil 54 is disposed within the housing 38 with the axial direction of the core 56 oriented in a direction intersecting (perpendicular to) the axial direction of the output shaft 26. In this case, as shown in FIGS. 10 and 11 , the magnet 52 is fixed to the center portion 46B of the gear wheel 46 with its axial direction oriented in the radial direction of the gear wheel 46. In the example shown in FIGS. 10 and 11 , members and parts corresponding to those of the wiper motor 14 described above are denoted by the same reference numerals as those of the wiper motor 14 described above.

[0039] Furthermore, in the present embodiment, an example in which a single magnet 52 is fixed to the gear wheel 46 has been described, but the present invention is not limited to this. For example, as shown in FIG. 12, a configuration may be employed in which a plurality of magnets 52, 96 having different magnetic forces are arranged on the same circumference of the gear wheel 46 at intervals in the rotational circumferential direction of the gear wheel. With this configuration, for example, as shown in FIG. 1, it is possible to stop each wiper member 18 at the upper reversal position P2 in addition to stopping each wiper member 18 at the lower reversal position P1. In the example shown in FIG. 12, the same reference numerals are used to designate components and parts corresponding to those of the wiper motor 14.

[0040] The above describes one embodiment of the present disclosure, but the present disclosure is not limited to the above, and it goes without saying that it can be implemented in various other modified forms within the scope that does not deviate from the gist of the present disclosure.

[0041] <Additional Notes> (Appendix 1) an output shaft (26) connected to a wiper member (18) for wiping a windshield glass (12) of a vehicle, the output shaft (26) rotating to displace the wiper member; a gear wheel (46) that rotates with the output shaft; a housing (38) in which the output shaft is supported and in which the gear wheel is housed; a magnet (52, 96) fixed to the gear wheel; a detecting section (54) having a core (56) formed in a rod shape using a magnetic material and a coil (58) formed around the core, with one axial end of the core facing the magnet; signal terminals (60, 62) supported by the housing and connected to the coil; A wiper motor (14) equipped with (Appendix 2) 2. The wiper motor according to claim 1, wherein the axial direction of the core is aligned with the axial direction of the output shaft. (Appendix 3) 2. The wiper motor according to claim 1, wherein the axial direction of the core is oriented in a direction intersecting the axial direction of the output shaft. (Appendix 4) The housing is provided with a connector portion (50A) to which an external connector is connected, The connector portion is provided with a terminal portion of the signal terminal and a terminal portion of a power supply terminal (64, 66) to which power for rotating the output shaft is supplied, 4. The wiper motor according to any one of claims 1 to 3, wherein both terminal portions of the coil are directly connected to terminal portions of the signal terminals, respectively. (Appendix 5) The housing includes a housing body (48) that is open on the gear wheel side, and a cover (50) that closes the open end of the housing body when attached to the housing body, the detection unit is fixed to the cover, 5. The wiper motor according to any one of claims 1 to 4, wherein the magnet and the detector are disposed at a position where they can face each other when the cover is attached to the housing body. (Appendix 6) The gear wheel has gear teeth formed on the outer side in the rotational radial direction, The magnet is fixed to a position closer to the inner side in the rotational radial direction of the gear wheel. 6. The wiper motor according to claim 1, wherein the wiper motor is a wiper motor having a diameter of 100 mm or more. (Appendix 7) A wiper motor according to any one of appendix 1 to appendix 6, wherein a plurality of the magnets, each having a different magnetic force, are arranged on the same circumference of the gear wheel at intervals in the circumferential direction of the gear wheel. (Appendix 8) A wiper motor according to any one of Supplementary Note 1 to Supplementary Note 7; the wiper member connected to the output shaft; a control unit (20) that controls the operation and stopping of the wiper motor; and The control unit stops the wiper motor when a signal indicating the stop of the wiper motor is detected and when it is detected that the induced electromotive force generated in the coil has reached a predetermined value. [Explanation of symbols]

[0042] 10 wiper device, 12 windshield glass, 14 wiper motor, 18 wiper member, 20 control unit, 26 output shaft, 38 housing, 46 gear wheel, 48 housing body, 50 cover, 50A connector unit, 52 magnet, 54 choke coil (detection unit), 56 core, 58 coil, 60 signal terminal, 62 signal terminal, 64 power terminal, 66 power terminal, 96 magnet

Claims

1. an output shaft (26) connected to a wiper member (18) for wiping a windshield glass (12) of a vehicle, the output shaft (26) rotating to displace the wiper member; a gear wheel (46) that rotates with the output shaft; a housing (38) in which the output shaft is supported and in which the gear wheel is housed; a magnet (52, 96) fixed to the gear wheel; a detecting unit (54) having a core (56) formed in a rod shape using a magnetic material and a coil (58) formed around the core, with one axial end of the core facing the magnet; signal terminals (60, 62) supported by the housing and connected to the coil; A wiper motor (14) comprising:

2. 2. The wiper motor according to claim 1, wherein the axial direction of the core is oriented in the axial direction of the output shaft.

3. 2. The wiper motor according to claim 1, wherein the axial direction of the core is oriented in a direction intersecting the axial direction of the output shaft.

4. The housing is provided with a connector portion (50A) to which an external connector is connected, The connector portion is provided with a terminal portion of the signal terminal and a terminal portion of a power supply terminal (64, 66) to which power for rotating the output shaft is supplied, 2. The wiper motor according to claim 1, wherein both terminals of said coil are directly connected to terminals of said signal terminals, respectively.

5. The housing is configured to include a housing body (48) that is open on the gear wheel side, and a cover (50) that closes the open end side of the housing body when attached to the housing body, the detection unit is fixed to the cover, 2. The wiper motor according to claim 1, wherein the magnet and the detector are disposed in a position where they can face each other when the cover is attached to the housing body.

6. The gear wheel has gear teeth formed on the outer side in the rotational radial direction, The magnet is fixed to a position closer to the inner side in the rotational radial direction of the gear wheel.

2. The wiper motor according to claim 1, wherein:

7. 2. The wiper motor according to claim 1, wherein a plurality of the magnets having different magnetic forces are arranged on the same circumference of the gear wheel at intervals in the circumferential direction of rotation of the gear wheel.

8. The wiper motor according to claim 1 ; the wiper member connected to the output shaft; a control unit (20) for controlling the operation and stopping of the wiper motor; and The control unit stops the wiper motor when a signal indicating the stop of the wiper motor is detected and when it is detected that the induced electromotive force generated in the coil has reached a predetermined value.

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