Motor having rotational sensor

DETAILED DESCRIPTION The present invention addresses the above disadvantages.
Thus, it is an objective of the present invention to provide a motor that has a reduced size and includes a rotational sensor and a coupling member, such as a clutch, for coupling a rotatable shaft of a rotor with a worm shaft.
To achieve the objective of the present invention, there is provided a motor including a motor case, a rotatable shaft, a worm shaft, a coupling member and a rotational sensor.
The rotatable shaft is rotatably supported by the motor case and is rotated upon actuation of the motor.
The worm shaft is substantially coaxial with the rotatable shaft and is rotatably supported by the motor case.
The coupling member includes a driving-side rotator and a driven-side rotator that is drivingly engageable with the driving-side rotator.
The driving-side rotator is connected to the rotatable shaft to rotate integrally therewith.
The driven-side rotator is connected to the worm shaft to rotate integrally therewith.
The rotational sensor includes a sensor magnet and a sensing element.
The sensor magnet rotates integrally with the rotatable shaft.
The sensing element measures a rotational speed of the sensor magnet.
The sensor magnet is secured to the driving-side rotator to rotate integrally therewith.
The sensing element is secured to the motor case in such a manner that the sensing element opposes the sensor magnet.