Alternator for vehicle

Abstract

It is an object of this invention to provide a compact high-power alternator for a vehicle which is good in cooling performance, efficiency, and cost without decreasing a coil resistance or using a magnet. The alternator for the vehicle includes a stator and a rotor. The rotor includes a Lundel-type iron core and a field coil provided on the Lundel-type iron core. The Lundel-type iron core has a cylindrical portion (71), a yoke portion (72), and a claw-like magnetic pole portion (73). The field coil is provided on the cylindrical portion (71). The yoke portion (72) extends from the cylindrical portion (71) in a radially outward direction. The claw-like magnetic pole portion (72) is connected to the yoke portion (72), and is formed so as to surround the field coil. The stator includes a multiple-layer iron core (32). A ratio of an axial-direction length L1 of the multiple-layer iron core (32) to an axial-direction length L2 of the cylindrical portion (71) of the Lundel-type iron core is in a range of 1.25 to 1.75. A ratio of an outside diameter R2 of the cylindrical portion (71) of the Lundel-type iron core to an outside diameter R1 of the claw-like magnetic pole portion (73) of the Lundel-type iron core is in a range of 0.54 to 0.60.

Dependencies are inferred from the claim text.