MOTOR UNIT

摘要

A rotation detector of a motor according to an embodiment includes a first support and a second support, a pair of magnetic field forming units, at least one magnetic field detector, and a first magnetic member and a second magnetic member. The first magnetic member and the second magnetic member are each made of a magnetic material, cover longitudinal-direction both ends of the magnetic field detector facing the first support, respectively, and face each other with a gap interposed therebetween at a longitudinal-direction mid-portion of the magnetic field detector in the longitudinal direction. A dimension of each of the magnetic field forming units in a tangential direction of a circumference is larger than a dimension of the corresponding magnetic field forming unit in a radial direction and is larger than the distance of the gap.

主权项

1. A motor unit comprising:
a motor configured to rotate a shaft about an axial line; and a rotation detector configured to detect rotation of the shaft, wherein the rotation detector comprises:
a first support and a second support that are provided in a manner separated from each other in a direction of the axial line, one of which is rotated along with rotation of the shaft using the axial line as a rotational axis;a pair of magnetic field forming units that is provided on the first support in a manner facing the second support at different positions along a circumference about the axial line and having different polarities;at least one magnetic field detector that is formed by winding a coil around a magnetic element whose magnetized direction changes in a longitudinal direction and provided on the second support such that a longitudinal-direction side of the magnetic element faces the first support; anda first magnetic member and a second magnetic member that are each made of a magnetic material, that cover longitudinal-direction both ends of the magnetic field detector facing the first support, respectively, and that face each other with a gap interposed therebetween at a longitudinal-direction mid-portion of the magnetic field detector, and a dimension of each of the magnetic field forming units in a tangential direction of the circumference is larger than a dimension of the corresponding magnetic field forming unit in a radial direction and is larger than the distance of the gap.