Sleeve type of coreless motor with reduced starting current

Abstract

According to the present invention, a coreless motor is provided, which comprises: a stator having a circular slot therein, magnets on a wall of the slot, two brushes attached thereto, and metals, which are arranged concentrically; and a rotor having a shaft rotatably supported by the metals, a coil assembly, and a commutator arranged around the shaft, the coil assembly having successive 1st to Nth coils in the slot confronting the magnets and (N+1) taps and a commutator including segments respectively connected to the (N+1) taps, the first to Nth coils connected to the segments through the (N+1) taps respectively, the two brushes selectively contacting with two of the segments successively. The 1st-Nth coils have a sleeve form and each has a rectangular winding pattern, the 1st-Nth coils and the (N+1) taps form a continuous wire, and a coil opening angle is substantially 180.degree. and a coil pitch is 180.degree./(N+1) to 360.degree./(N+1). Open end coils may be provided both ends of 1st-Nth coils to provide loop form taps. The coils may be formed of a high tensile force strength wire. That is, the coils may comprise an alloy including at least copper and silver and having a resistivity from 2.mu..OMEGA..multidot.cm to 3.5.mu..OMEGA..multidot.cm and a tensile force strength from 200 N/mm.sup.2 to 500 N/mm.sup.2.