Reluctance-type motor having widened bottom

DETAILED DESCRIPTION It is therefore an object of the present invention to provide a reluctance-type motor that has less drop in output torque and hence less ripple in the output torque even salient poles of a rotor and a stator completely face each other.
According to the present invention, a reluctance-type motor comprises a core for a rotor or a stator.
The core has a cylindrical ring and a plurality of salient poles protruding from the ring in a radial direction of the ring.
Each pole has a bottom width and a top width in a circumferential direction of the core at its bottom which is connected to the ring and at its top which is away from the ring, respectively.
The bottom width (D1) is sized to be larger than the top width (D2), and the ring has a width in a radial direction of the core to allow at least a half of magnetic flux in the pole to pass through the ring.
Preferably, the width of the ring is sized to be larger than a half of the top width of the pole.
The pole is shaped to have a round corner at the bottom or in a trapezoid in which the bottom width is larger than the top width.
The core has a plurality of thin magnetic plates stacked in an axial direction of the core, each plate has a plurality slits in each protrusion which forms the pole, and each plate has a thickness which is less than 5 times of a maximum width of each slit.