Small stepper motor with maximum stator teeth per pole
AssigneeLin Engineering, Inc.
InventorsTed T. Lin, Richard L. Badgerow
Life of this patent
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Abstract
A step motor having a stator constructed with six teeth per pole is achieved for a stator inner diameter (ID) less than one inch (25.4 mm) by a either (1) reducing the pitch angle of the outer teeth of each pole (e.g., to at most 6.8 degrees for a 19 mm stator ID), or (2) narrowing the tooth width of those outer teeth (e.g., to at most 0.0175 inch or 0.444 mm for a 19 mm stator ID), or (3) combination of both. These changes allow sufficient space (i.e., wider than 0.052 inch or 1.321 mm) between poles for passage of a winding needle, even with the extra stator teeth. Although narrowing the pitch angle and reducing the tooth width do sacrifice some torque contribution from each tooth, there still results a net overall gain in torque.
Claims13
A stepper motor, comprising:
- a rotor with a plurality of rotor teeth, the rotor fitting within a stator winding assembly and seated by bearings on an axial shaft so as to rotate within the stator winding assembly,
- the stator winding assembly including a stator with a set of stator poles wound with coils that can be driven in a series of phases so as to magnetically interact with the rotor with a characteristic step angle, the stator characterized by an inner diameter of less than 1 inch (25.4 mm), each stator pole having at least six stator teeth adjacent to the rotor teeth with stator tooth pitch and stator tooth width being such that a gap between outermost teeth of adjacent stator poles is wider than 0.052 inch (1.321 mm).
A 1.8-degree stepper motor, comprising:
- a rotor with a plurality of rotor teeth, the rotor fitting within a stator winding assembly and seated by bearings on an axial shaft so as to rotate within the stator winding assembly,
- the stator winding assembly including a stator with a 8 stator poles wound with coils that can be driven in a series of phases so as to magnetically interact with the rotor with a 1.8° step angle, the stator characterized by an inner diameter of less than 1 inch (25.4 mm), each stator pole having six stator teeth adjacent to the rotor teeth with stator tooth pitch and stator tooth width being such that a gap between outermost teeth of adjacent stator poles is wider than 0.052 inch (1.321 mm).
Dependencies are inferred from the claim text.