Small DC motor
AssigneeMinebea Motor Manufacturing Corporation
InventorMinoru Kuroda
Life of this patent
Estimating the term…
Abstract
A small DC motor includes: a motor frame including a cylindrical portion, the cylindrical portion having a constant thickness and having a cross section in a shape that includes four sides and connecting portions, each of the connecting portions connecting adjacent two of the four sides and being located inward from a corresponding corner in a quadrangle including the four sides; field magnets; and an armature assembly, wherein the field magnets are provided so as to be spaced apart from each other, and the small DC motor includes an air gap between each of the four sides and a radially outermost surface of the armature assembly, the air gap being a minimum size needed to rotate the armature assembly.
Claims6
A small DC motor, comprising:
- a motor frame comprising a cylindrical portion and an end plate portion, the cylindrical portion having a constant thickness and having a cross section in a shape that comprises four sides and connecting portions, each of the connecting portions connecting adjacent two of the four sides and being located inward from a corresponding corner in a quadrangle comprising the four sides;
- field magnets, each being positioned adjacent to each of the connecting portions, having an arc-shaped surface on an inside thereof and having a cross section in an inside portion that has an arc-shape and in an outside portion that has a same curvature as an inside surface of the connecting portions, and
- an armature assembly comprising an armature winding and a shaft and being disposed rotatably within the motor frame,
- wherein the field magnets are provided so as to be spaced apart from each other,
- wherein the small DC motor comprises an air gap between each of the four sides and a radially outermost surface of the armature assembly,
- wherein a radius from the center of the shaft to an inside surface of the motor frame is substantially same as a radius from the center of the shaft to the arc-shape surface of the inside portion of the field magnets, and wherein the air gap is set in a range of 0.1 mm to 0.5 mm.
Dependencies are inferred from the claim text.