Stator with molded encasement for small motors and manufacturing process therefor

A stator for precision motors, comprising:

• a lamination stack;
• a first insulation layer injection molded onto said lamination stack and coil winding guides formed simultaneously with the first insulation layer on a top side of said lamination stack, said first insulation layer and said coil winding guides being formed of a high flow thermoplastic synthetic resin which is an electrical insulator, said first insulation layer coating at least top and bottom surfaces and surfaces of slots of said lamination stack in the form of a thin resin skin insulation;
• a coil of insulated thin copper wire wound over said first insulation layer and said winding guides;
• and
• a second insulator layer injection molded on said coil using said high flow thermoplastic synthetic resin used for said first insulation layer and said coil winding guides to encase said coil and inhibit exposure of said coil to an outside environment.

A method for producing a stator with a lamination stack, comprising:

• inserting the lamination stack into a first molding tool installed on an injection molding machine;
• injection molding onto said lamination stack a first insulation layer, which is a thin resin skin, and coil winding guides, each being formed of a high flow thermoplastic synthetic resin which is an electrical insulator, said first insulation layer coating at least top and bottom surfaces and surfaces of slots of said lamination stack and said coil winding guides being formed integral with said first insulation layer on said top surface of said lamination stack;
• winding a coil of insulated thin copper wire over said first insulation layer and said winding guides;
• inserting said lamination stack with said coil into a second molding tool having an interior cavity for accepting said lamination stack and a gate communicating with said interior cavity and disposed at a location where injected resin will not directly hit said coil;
• and
• injection molding a second insulator layer on said coil using said high flow thermoplastic synthetic resin injected at a peak filling pressure in a range about 20 to 60% lower than a standard value for said high flow thermoplastic synthetic resin and at an injection speed more than twice as high as a standard injection speed for said high flow thermoplastic synthetic resin.

A method for producing a stator with a lamination stack, comprising:

• inserting the lamination stack into a first molding tool installed on an injection molding machine;
• injection molding onto said lamination stack a first insulation layer formed of a high flow thermoplastic synthetic resin which is an electrical insulator, said first insulation layer coating at least portions of top and bottom surfaces and surfaces of slots of said lamination stack;
• winding a coil of insulated wire over said first insulation layer;
• inserting said lamination stack with said coil into a second molding tool having an interior cavity for accepting said lamination stack and a gate communicating with said interior cavity and disposed at a location where injected resin will not directly hit said coil;
• and
• injection molding a second insulator layer on said coil using said high flow thermoplastic synthetic resin injected at a peak filling pressure in a range about 20 to 60% lower than a standard value for said high flow thermoplastic synthetic resin and at an injection speed more than twice as high as a standard injection speed for said high flow thermoplastic synthetic resin.