Cooling structure for alternator rectifier

Claim 1

An improved bridge rectifier for a rotary electromotive machine having a main rotary axis comprising; a first metallic heat sink that is adapted to engage an end frame of the electromotive machine when the bridge rectifier is mounted to the electromotive machine; a second metallic heat sink; an electrical insulator sandwiched between said heat sinks for electrically insulating said heat sinks from each another; a first group of semiconductor diode chips supported by said first heat sink such that they are electrically connected to and in heat transfer relationship with said first heat sink; a second group of semiconductor diode chips supported by said second heat sink such that they are electrically connected to and in heat transfer relationship with said second heat sink; wherein the improvement comprises: said second heat sink being formed with an arcuate portion having substantial length in a direction parallel to said main rotary axis and partially surrounding said main rotary axis of said electromotive machine and including multiple radial air passageways for the passage of cooling air in a direction parallel to said main rotary axis; said second heat sink further including an undercut circumferential groove around an inner diameter of said arcuate portion substantially midway along said length thereof; said groove having a depth sufficient to intersect an inner radial end of said air passageways to allow for and direct the additional passage of cooling air into said groove and in an inward radial direction thus substantially increasing the air flow through and thus the cooling effect of said second heat sink.