Bobbin for armature of rotary electrical machine

1. An insulator for an armature core of a rotating electrical machine, the core having an annular section from which a plurality of circumferentially spaced teeth extend in a radial direction and defining slots therebetween, said insulator being comprised of a cylindrical portion having a plurality of circumferentially spaced tooth covering portions extend in radial directions, each of said tooth covering portions having a generally channel shape in radial cross sections for covering a radial face of a respective of the core teeth and at least a portion of the side surfaces of the tooth facing the slots between adjacent of the teeth, the radially outermost part of each of said tooth covering portions being formed with an axially extending flange to form an abutment against which a coil winding is abuttingly engaged, said insulator being formed with a slot like recess contiguous to said axially extending flange to trap the wire of the coil winding end to prevent it from slipping along the generally channel shape portion in a radial direction.

2. An insulator as set forth in claim 1 wherein the recess is formed in the axially extending flange.

3. An insulator as set forth in claim 2 wherein the recess is tapered from the radially inner end of the flange toward its circumferential center.

4. An insulator as set forth in claim 3 wherein there are a pair of like formed recess on opposite sides of the flange.

5. An insulator as set forth in claim 2 wherein the recess is formed as a slot along the radially inner edge of the flange extending circumferentially toward the center of the flange.

6. An insulator as set forth in claim 5 wherein the slot along the full length of the flange extending circumferentially toward the center of the flange.

7. An insulator as set forth in claim 2 wherein the recess is formed by a step in the axial end of the flange.