Abstract: In an alternating current generator for vehicles, an output terminal of a rectifier circuit is tightly fixed to a positive-polarity side heat radiation fin by tightening a nut. A resin bushing is fitted around the nut to insulate electrically the output terminal. The bushing has a flange on its outer peripheral surface. A rear cover made of resin is attached to cover the flange, so that the rear cover restrains the bushing from moving along and turning around the output terminal.

Abstract: A rotor of an alternator having a plurality of claw poles, a plurality of auxiliary permanent magnets and a magnet holder for the permanent magnets. The magnet holder is composed of soft resinous holding members, connecting bands and heat-resistant members. Each of the heat resistant members is disposed between the claw poles and holding members to prevent heat transfer from the claw poles to the holding members.

Abstract: The present invention prevents the degradation of the power generating efficiency of an alternating current generator by preventing the expansion of an air gap formed between pole cores and a stator core, achieves low-noise operation by preventing generation of high-frequency impact magnetic noise, and makes it possible to relieve strains applied on a magnet holder. The present invention utilizes sixteen magnets, each of which fits between two of sixteen claw-like magnetic poles formed on the outer periphery of Lundell-type pole cores, which rotates integrally with a shaft. The magnets are caught and stopped by a magnet holder which has been formed by interconnecting zig-zagging segments and has elasticity as a whole. Here, the permanent magnets are held by the magnet holder so that the magnet holder does not protrude towards the rotor side from the outer peripheral face of the Lundell-type pole cores and the contacting faces of the magnet holder contact the outer faces of the permanent magnets.

Abstract: A sealed rectifier used in a vehicle alternator is composed of a semiconductor diode chip, a base electrode having a disk plate which has a central mount for supporting the chip and an annular wall extending higher than the central mount, a pole electrode having a flange connected to the other side of the chip and an insulating member covering the chip, base electrode and pole electrode. The thickness of the annular wall is smaller than the thickness of the central mount, the outer periphery of the disk plate has a serrated surface for mechanical connection with an cooling fin of the alternator, and the insulating member is composed of resinous material and inorganic filler material to provide residual internal pressure higher than the atmospheric pressure.

Abstract: The present invention prevents the degradation of the power generating efficiency of an alternating current generator by preventing the expansion of an air gap formed between pole cores and a stator core, achieves low-noise operation by preventing generation of high-frequency impact magnetic noise, and makes it possible to relieve strains applied on a magnet holder. The present invention utilizes sixteen magnets, each of which fits between two of sixteen claw-like magnetic poles formed on the outer periphery of Lundell-type pole cores, which rotates integrally with a shaft. The magnets are caught and stopped by a magnet holder which has been formed by interconnecting zig-zagging segments and has elasticity as a whole. Here, the permanent magnets are held by the magnet holder so that the magnet holder does not protrude towards the rotor side from the outer peripheral face of the Lundell-type pole cores and the contacting faces of the magnet holder contact the outer faces of the permanent magnets.

Abstract: An alternator has front and rear cooling fans to effectively cool the stator windings and field coil of the alternator. The front cooling fan has a first number (e.g. six) of diagonal-flow type blades for cooling mainly the field coil and a second number (e.g. five) of centrifugal-flow-type blade for cooling the stator windings which are disposed between the diagonal-flow-type blades. The combination of the first and second numbers is designed to suppress noise level caused by the cooling fan.

Abstract: Cooling wind is introduced into an electric-parts-chamber through openings formed at the bottom of a cover, then taken into the intake side of a cooling fan through the air intakes formed in the wall end of a housing from the electric-parts-chamber. The cooling wind is accelerated by the fan to be driven off from the outlets formed in the peripheral wall of the housing. The cylindrical portion of the positive side cooling fins of the rectifier is extended to the space between the outer periphery of the fan and the outlets. The inner diameter of the cylindrical portion is longer than that of the rear coil end. Thus, the coil end and the cylindrical portion of the positive side cooling fin are cooled sufficiently by the cooling wind blowing thereon at high speed, so that the rectifier can endure large thermal load with reduced wind noise even if the size of the alternator is small.

Abstract: The present invention prevents the degradation of the power generating efficiency of an alternating current generator by preventing the expansion of an air gap formed between pole cores and a stator core, achieves low-noise operation by preventing generation of high-frequency impact magnetic noise, and makes it possible to relieve strains applied on a magnet holder. The present invention utilizes sixteen magnets, each of which fits between two of sixteen claw-like magnetic poles formed on the outer periphery of Lundell-type pole cores, which rotates integrally with a shaft. The magnets are caught and stopped by a magnet holder which has been formed by interconnecting zig-zagging segments and has elasticity as a whole. Here, the permanent magnets are held by the magnet holder so that the magnet holder does not protrude towards the rotor side from the outer peripheral face of the Lundell-type pole cores and the contacting faces of the magnet holder contact the outer faces of the permanent magnets.