Rectifying apparatus for an automotive AC generator

An automotive AC generator comprising:

• a stator;
• a rotor cooperating with said stator to generate an AC voltage;
• bearings rotatably supporting said rotor;
• a cooling fan disposed at least at one axial end of said rotor;
• a rectifier for converting the AC voltage into a DC voltage, said rectifier being disposed at an axial direction of said rotor;
• a partition plate isolating said rectifier from said cooling fan;
• a frame fixedly securing said stator, said bearings, and said rectifier;
• said rectifier comprising:
• a number of positive rectifying elements:
• a larger-diameter fin of positive electric potential for mounting said positive rectifying elements, said larger-diameter fin having a radial-inner end, and being disposed adjacent to said partition plate with a predetermined axial clearance;
• a number of negative rectifying elements cooperating with the number of positive rectifying elements, each rectifying element having a lead extending therefrom;
• and
• a smaller-diameter fin of negative electric potential for mounting said negative rectifying elements, said smaller-diameter fin having a radial-outer end, and being disposed adjacent to said frame and separated therefrom with a predetermined axial clearance;
• wherein, said larger-diameter and smaller-diameter fins are arranged parallel to each other in an axial direction with a predetermined clearance therebetween so that said leads extend in opposite directions in a space between said larger-diameter and smaller-diameter fins;
• wherein the radial-inner end is disposed adjacent to said negative rectifying elements, and extends radially outward therefrom;
• wherein the radial-outer end is disposed adjacent to said positive rectifying elements, positioned between said positive rectifying element and said frame, and extending in a direction towards said frame;
• and
• wherein the axial opening introduces external air;
• a radial ventilation passage disposed between said larger-diameter fin and said partition plate for passing air along a central position of said positive rectifying element;
• and
• an opening formed on said frame for introducing external air directly to the radial-outer end of said radial ventilation passage;
• wherein said frame is directly brought into contact with and fixed to said fin which mounts said negative rectifying elements.

An automotive AC generator comprising a rotor, a stator, a rectifier, and a frame securely fixing said rotor, said stator and said rectifier, wherein,

• a cooling fan is provided at an end of said rotor,
• said frame comprises an inner wall member serving as a shroud positioned in a confronting relationship with an axial front end of said cooling fan and an outer wall member covering said rectifier;
• said rectifier is disposed between said inner wall member and said outer wall member;
• said rectifier comprises a first platelike cooling fin disposed in parallel with a wall surface of said inner wall member and having a mount portion for mounting a plurality of rectifying elements, a second platelike cooling fin disposed at a position axially outer than said first platelike cooling fin in parallel to said first platelike cooling fin and having a mount portion for mounting a plurality of rectifying elements;
• an inside clearance serving as a cooling air passage is formed between said inner wall member and the mount portion of said first platelike cooling fin;
• an outside clearance serving as a cooling air passage is formed between said outer wall member and the mount portion of said first platelike cooling fin;
• said outer wall member has an opening communicating with said inside clearance, and another opening communicating with said outside clearance;
• and
• said two openings are formed at different portions on an outer surface of said frame so that cooling air is introduced inside said frame via said inside clearance and said outside clearance independently.