Device and method for molding motor coils

A motor coil molding method for molding coils wound around a motor rotor with resin material, comprising:

• providing a die assembly having a first half and a second half and defining a die cavity therein, said die cavity including a main part for receiving a rotor core coaxially therein so as to define a small annular gap between the rotor core and the opposing die surface, and at least a first support portion for supporting a shaft end of the motor rotor, said die cavity further including at least a first constraining portion jointly defined by said first half and said second half of said die assembly, said first constraining portion being located between said main part and said first support portion, said first constraining portion having an inner diameter smaller than an inner diameter of said main part;
• placing a motor rotor in said first half of said die assembly;
• radially constraining a coil end at an axial end of the rotor core with said first constraining portion jointly defined by said first half and said second half of said die assembly as said first half and said second half are brought together in a radial direction;
• injecting resin material from a radially peripheral part of said die assembly so as to force coil wire received in core slots radially inward by a flow of said resin material;
• and
• curing said resin material deposited around the motor rotor, said die cavity including a second support portion for supporting an opposite shaft end of the motor rotor, and a second constraining portion jointly defined by said first half and said second half of said die assembly, said second constraining portion being located between said main part and said second support portion, said second constraining portion having an inner diameter smaller than an inner diameter of said main part, and
• further comprising radially constraining a coil end at an opposite axial end of the rotor core with said second constraining portion as said first half and said second half are brought together in a radial direction.

A motor coil molding method, comprising:

• winding coil wire around a motor rotor having a plurality of core slots provided therein, two axial ends of said motor rotor each defining a coil end, said coil wire being received in said core slots;
• placing said motor rotor in a die cavity of a die assembly, said die assembly having a first half and a second half, said die cavity including a main part for receiving a rotor core coaxially therein, and first and second constraining portions jointly defined by said first half and said second half of said die assembly;
• supporting said motor rotor with first and second support portions in said die cavity of said die assembly;
• radially constraining each coil end with an associated one of said first and second constraining portions of said die assembly as said first half and said second half are brought together in a radial direction, said first constraining portion being located between said main part and said first support portion, said first constraining portion having an inner diameter smaller than an inner diameter of said main part, said second constraining portion being located between said main part and said second support portion, said second constraining portion having an inner diameter smaller than an inner diameter of said main part;
• injecting resin material from a radially peripheral part of said die assembly around said motor rotor;
• and
• curing said resin material deposited around said motor rotor.

A motor coil molding method, comprising:

• winding coil wire around a motor rotor having a plurality of core slots provided therein, an axial end of said motor rotor defining a coil end, said coil wire being received in said core slots;
• placing said motor rotor in a die cavity of a die assembly, said die assembly having a first half and a second half, said die cavity including a main part for receiving a rotor core coaxially therein, and first and second constraining portions jointly defined by said first half and said second half of said die assembly;
• supporting said two axial ends of said motor rotor with first and second support portions, respectively, in said die cavity of said die assembly;
• radially constraining said coil end with one of said first and second constraining portions of said die assembly as said first half and said second half are brought together in a radial direction, said first constraining portion being located between said main part and said first support portion, said first constraining portion having an inner diameter smaller than an inner diameter of said main part, said second constraining portion being located between said main part and said second support portion, said second constraining portion having an inner diameter smaller than an inner diameter of said main part;
• injecting resin material from a radially peripheral part of said die assembly around said motor rotor;
• and
• curing said resin material deposited around said motor rotor.