Suzhou Firstall Electrical Machine & Technology Co.,Ltd.

A vehicularAC generatorcomprising a magnetic pole core secured to a shaft and excited by an excitation coil, the magnetic pole core having opposite end faces, a stationary core surrounding the magnetic pole core and having mounted thereon a stationary coil, and a front and a rear bracket supporting the stationary core and rotatably supporting the shaft through bearings.

Accordingly, one object of the presentbrushless alternatoris to provide a vehicular AC generator free from the above-discussed problems.Another object of the present invention is to provide a vehicular AC generator in which an overall sound pressure level of the wind noise can be decreased.
Another object of the present invention is to provide a vehicular AC generator in which the sound pressure level of the frequency multiplied by the number of the fan blades and the frequency multiplied by the even number of the inlet openings can be decreased, thereby eliminating annoying noise characteristics.
Still another object of the present invention is to provide a fan arrangement for a brushless ac generator in which the sound pressure level of the frequency of the order of the multiple of the number of the magnetic pole pieces therewithin is decreased.
With the above objects in view, the vehicular AC generators according to the present invention comprises a magnetic pole core secured to a shaft and excited by an excitation coil, a stationary core surrounding said magnetic pole core and having mounted thereon a stationary coil.
The fan arrangement of another aspect of the present AC generator is characterized in that the blade configuration includes a straight blade and a curved blade, that the blades are arranged at different circumferential intervals, and that the inner end of all the blades are disposed at the same distance from the center of rotation.
In this arrangement, the frequencies of wind noise generated by the rotation of the fan is dispersed, and the sound pressure level of various frequencies is supressed so that the overall level can be advantageously reduced.

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AC generator stator coil with noise reduction

In an ac generator having a claw-pole type rotor, a stator winding has a plurality of front and rear coil ends. Each of the rear coil ends has an inside bent portion extending radially outward from the inner periphery of the rear end of the stator core and an inside main portion extending axially from the bent portion to form a backwardly expanding space around the rotor.

The present ac alternator application is based on and claims priority from Japanese Patent Application Hei 10-79412 filed on Mar. 26, 1998, the contents of which are incorporated herein by reference.

A rotor of a conventional brushless alternator has a pair of pole cores having a base portion and a plurality of claw pole pieces extending axially from the base portion disposed at opposite ends of the rotor. A stator core of conventional ac generators have a plurality of coil ends extending from opposite ends thereof to surround the circumference of the claw poles. A centrifugal cooling fan is fixed to an end of the rotor to cool the plurality of coil ends.

It has been found that fan noise is caused when circulating air C1, as shown in FIG. 2, driven by such a centrifugal cooling fan is interrupted by inner peripheral surfaces C2 of the coil ends surrounding the centrifugal fan.

A main object of the brushless ac generator is to provide an improved structure for reducing fan noise and noise generated when cooling air is interrupted by the coil ends, thereby improving cooling efficiency.

According to the ac generator, each of the rear coil ends of a stator winding has an air guiding inside surface. The air guiding inside surface is composed of an inside bent portion inclining or expanding radially outward from the inner periphery of the rear end of the stator core and an inside main portion extending axially from the bent portion to form a backwardly expanding space around a rear portion of the rotor. As a result, cooling air is guided by the inside surface to expand so that the speed and density of the cooling air can be regulated.

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AC Generator with low noise claw tooth rotor

An AC generator for a vehicle comprises a rotor having a pair of finger magnetic poles and an armature iron core. By deviating pole pieces of the finger magnetic poles by predetermined angles relative to each of opposed tooth portions of the armature iron core, torque variation applied to each of the pole pieces during rotation is cancelled, and magnetic sound can be greatly decreased without reducing the output of the .

The present brushless alternator relates to AC generators for vehicles, more particularly to a multiphase, particularly three-phase, AC generator provided with a so-called Lundell type rotor comprising an exciting coil enclosed by a pair of finger magnetic poles having a plurality of pole pieces, respectively. Such a generator is chiefly installed on vehicles, with the rotor driven by an engine thereof.

As is well known in the art, brushless alternators(hereinafter simply referred to as ACG) as described above generally have a basic construction such as shown in FIG. 1. In FIG. 1, reference numeral 1 designates an armature iron core of a cylindrical shape, and reference numeral 2 designates three-phase armature windings wound about the iron core 1. The armature assembly comprising these elements is supported within two housings H. Reference numeral 3 designates a three-phase full wave rectifier unit contained in one of the two housings H, for converting the output of the armature windings 2 into DC current.

According to the present brushless ac generator, in order to decrease the magnetic sound which is generated due to the torque variation, at least two pole pieces of at least one of a pair of finger magnetic poles are arranged so as to be deviated relative to the opposed tooth portions of the armature iron core which are arranged at an equal pitch, so that the pole pieces may be passed through the tooth portions of the armature iron core irregularly, when the rotor is rotated. As a result, the torque variation having a fundamental frequency TN and the integral order harmonics thereof, can be sharply decreased and the magnetic sound generated due to the torque variation can be greatly reduced.

Having now fully described the AC generator, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

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Ac generator having built-in voltage regulator

An ac generator for a vehicle includes a rotor having a field coil, a stator having a stator winding disposed around the rotor to provide ac power in cooperation with the rotor, a brush unit disposed near a rotation axis of the rotor, and a voltage regulator for controlling output voltage of the ac power. The voltage regulator has a regulator circuit section and a heat sink for dissipating heat generated by the regulator circuit section.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority from Japanese Patent Application 2003-172818, filed Jun. 18, 2003, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present ac generators relate to a brushless ac generator for a vehicle such as a passenger car or a truck.

2. Description of the Related Art

As disclosed in JP-A-85402, an ordinary voltage regulator that is mounted in an ac generator for a vehicle has a unitary molded body that includes a circuit board on which an IC chip or transistors are mounted, a heat sink that is fixed to the circuit board by a heat conductive cement and a male connector. Therefore, cooling air is guided by the cooling fins to flow in a radial direction toward the center axis of the ac generator. Because a brushless alternator of an ordinary ac generator for a vehicle, which has a pair of brushes, is disposed between the voltage regulator and the center axis, the brushes are exposed to the cooling air that has cooled the voltage regulator, or has been heated by the voltage regulator.

SUMMARY OF THE INVENTION

Therefore, a main object of the present invention is to provide an improved ac generator for a vehicle in which the brushes are not excessively heated.

According to a main feature of the invention, an ac alternator for a vehicle includes a rotor having a field coil, a stator having a stator winding and is disposed around the rotor, a brush unit disposed near a rotation axis of the rotor, a voltage regulator for controlling output voltage of the ac power. With the above structure, the voltage regulator has a regulator circuit section and a heat sink for dissipating heat generated by the regulator circuit section, and the heat sink has a plurality of axially projecting cooling fins that extends in a circumferential direction of the rotor.

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Description of the ac generator system

This invention relates to an ac generator system and more particularly to a method and system for controlling connection of a supply of Ac to a load and to a power supply grid.

The Ac generator system disclosed in US2002/0030365 may transition from the power on-line state to the power off-line state. The power off-line state performs the functions of opening the contactor that connects the system to the grid, switching the main inverter of the system to a voltage mode (in contrast to the brushless alternator on-line state which enables the main inverter in a current mode) and setting the power level to a nominal level to power local loads. In the on-line state, the system samples the grid frequency and synchronizes its Ac output voltage with the voltage of the grid. When the line power unit is operating in a stand-alone mode or when the utility grid is not available (i.e. off-line) it is necessary for the system to synthesize a frequency so that the output power frequency is self-regulating.

During normal independent operation of the generator set described and illustrated in WO01/56133, the output AC voltage is controlled in accordance with one or more references which are generated by or within the generator set or as it is being set up for operation. Active and reactive power consumption is dependent on loads to which the Ac output of the generator set is connected.

An object of this brushless ac generator is to provide for improved connection and disconnection of the Ac output of an Ac generator system of the kind referred to hereinbefore to a power supply grid.

Connection and/or disconnection of the ac alternator of an Ac generator system of the kind referred to hereinbefore to a power supply grid needs to take account of the fact that the grid voltage may be out of phase and at a different frequency to the Ac output of the Ac generator system of the kind referred to hereinbefore when the latter is being operated independently.

Broadly in accordance with this invention the control of the Ac output of an Ac generator system of the kind referred to hereinbefore is disabled and the Ac output of the Ac generator system of the kind referred to hereinbefore is brought into harmony with the grid voltage, both in phase and frequency. By this invention, one or more references that are generated by or within the generator set or that were established as the generator set was being set up for operation and which determined the AC output voltage, are replaced by references derived from the grid data.

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Picking The Best AC Generator For You

The AC generator provide a convenient source of power for your home or business. There are a lot of these devices in the market; nevertheless, learning about a few basic concepts can help you choose the best one for you.
Stable power source is an important commodity, any family or business institutions should have. You have to make sure that you have a reliable power source in order for you to maintain the highest level of comfort and convenience in your house. Similarly, in order for your store or shop to give quality service, you need to be certain that brownouts and power interruptions will not affect the processes in your business.
Find an alternator is very easy. Electrical appliances shops in brushless ac generator, home decoration stores, sales of hardware companies and other organizations You can even order a brushless alternator from an online purchasing site and have it delivered to your home or office. However, with the vast number of AC generators in the market, you may find yourself in a jam as to which generator to get.
However, through the simple steps to set up, you can choose your ac alternator. The most important thing you have to do is to determine the amount of electricity you require for your specific case. For this purpose, you should have a clear idea of the fundamental measurements related to electricity: volts, amperes, and watts. Volts pertain to the amount of electrical pressure provided by the power source. Small appliances in your home run on 120 volts, while larger pieces of equipment run on 240 volts.

In addition to electric power to know to understand the alternator parts will also help you choose one that suits your requirements.

First, the engines of AC generators may run on gasoline, liquid propane, natural gas, or diesel fuel. Normally, you would want to opt for an engine that uses gasoline. In addition, it is a good idea to get an AC generator with an engine that has a well-known brand name and has service centers in your city.

The next important part of an AC generator is the alternator, which is directly responsible for producing electricity. Get a generator that has an alternator with a metal design as this would surely last longer.

Finally, there are other features that you might want to look for in an AC generator. A common example of these features is the idle control, which automatically throttles down the engine when no power is being drawn from the generator.

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AC generator for vehicle
An AC generator has negative pole-side rectifier devices press-fitted to a holder fin so as to dispose a bottom face of the rectifier device on a surface of the holder fin. The holder fin is disposed in such a manner that the bottom face of the rectifier device faces a rear frame of the AC alternator. A clearance is formed between the rear frame and the bottom face through which the cooling wind for the rectifier device flows. The rear frame is provided with a slant face on its outer wall face for inducing the cooling wind introduced through an opening of the protection cover of the AC generators to the rectifier devices. Thus, the cooling wind induced by the slant face can hit on the bottom face of the rectifier devices directly, so as to cool the rectifier device well.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority of Japanese Patent Application No. 2004-94918 filed on Mar. 29, 2004, the contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to an AC generator for vehicles, especially relates to a brushless AC alternator targeting on an improvement of cooling performance for a rectifier located therein.
BACKGROUND OF THE INVENTION
Currently, a large power output is demanded for brushless alternator
for vehicle, making a key issue in improving a cooling ability for a rectifier located therein, which generates a large amount of heat by a large current flowing therethrough. It is considered to raise an ability of fans for cooling the rectifier, however, this increases a noise of the fans. Thus, to secure a vehicular compartment against noise, it is not always appropriate to raise the cooling ability of the fans.
SUMMARY OF THE INVENTION
The present invention is achieved in view of the above issues, and its object is to provide an AC generator for a vehicle that has a high cooling ability for the rectifier device without raising an ability of a cooling fan and that can efficiently discharge muddy water intruded inside of a protection cover.
To achieve the above object, an AC generator for a vehicle of the present invention has a rotor, a frame having a slant face, a cooling fan, a protection cover and a rectifier.

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Ac generator
An ac generator includes a stator having a stator core with a plurality of slots and a stator winding disposed in the slots and a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other. In such an ac alternator, each pole piece has a chamfered surface at the tip. The chamfered surface increases a distance from the inside surface of the stator core as the chamfered surface becomes away from the circumferential center of the pole pieces. The chamfered surface has narrower area at the front half in the rotation direction than the rear half.
Background of the ac generator
1. Field of the ac generator
The present invention relates to an ac generator that has a rotor having a plurality of claw-shaped pole pieces and a field coil held inside the pole pieces.
2. Description of the ac generator
It has been found that the magnetic noise of brushless ac generator is caused by the third harmonic wave of magnetic flux that is distorted during operation. In order to reshape the waveform of the magnetic flux into a sine wave, JP-B2-61-11066 proposes an ac generator in which a rotor has scalene trapezoidal claw-shaped pole pieces. That is, the surface of the pole pieces has a trapezoidal shape that is asymmetrical with respect to the center line of the pole piece that is perpendicular to the rotation direction of the rotor.
Summary of the ac generator
Therefore, an object of the invention is to provide a powerful and noiseless ac generators.
An ac generator according to a feature of the invention includes a rotor having trapezoidal claw-shaped pole pieces that alternately extend in opposite directions to interleave each other, in which each of the pole pieces has a chamfered surface at the tip thereof that faces the inside surface of the stator. The chamfered surface has narrower area at the front half of the pole piece in the rotation direction than the rear half. Because such an asymmetrical chamfered surface is formed at limited area after the pole pieces are forged, the pole pieces having accurate size and shape can be provided. When the rotor with such pole pieces and a field coil is rotated in a predetermined direction to brushless alternator, the magnetic flux sharply increases at the front half of the chamfered surfaces of the pole pieces. On the other hand, the magnetic flux gradually decreases at the rear half of the chamfered surfaces. Therefore, a magnetic wave that is similar to the wave provided by the scalene trapezoidal pole pieces of a prior art ac generator is formed.

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