JPH04112653A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To obtain an AC generator for vehicle which can realize high speed rotation by optimizing the ratio between the inner diameter and the thickness of stator, in case of 16 poles, according to a specific formula. CONSTITUTION:A rotor 1 is excited by a DC exciting current to be fed to a field winding 2 and rotates with N and S poles being produced alternately in claw poles 111 arranged on the outer periphery of rotor thus inducing an AC three-phase output in a stator coil 12. When the inner diameter Di and the lamination thickness L of stator core are set such that 0.20<=L/Di<=0.24 for 16 field poles, output/mass ratio is improved to allow high speed rotation. When Do=l28, for example, Di=95mm and L=20mm and thereby L/Di=0.21 thus producing an output substantially equivalent to that in case of 12 poles and realizing high speed operation upto 22000rpm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle alternator with improved power generation output/mass ratio characteristics.

[Conventional technology]

Fuel efficiency regulations for automobiles have become increasingly strict in recent years.
Reducing weight is an effective way to improve fuel efficiency, and it is necessary to improve the power output/mass ratio of automotive alternators as well.

As an improvement plan of this type, an optimal design method for the stator core chair width and back core width is proposed in Japanese Utility Model Publication No. 57-6373.

The output (VA) of an alternator is generally expressed by equation (1).

■A=ni-Bg・ψ・a c-Dt” L-N-(1)
Here, K: Constant B1: Air gap magnetic flux density ψ: Polar arc ratio ac: Number of ampere conductors per pole Dl = Stator core inner diameter L: Stator core stack thickness N: Generator rotation speed From equation (1), power generation output mass of the generator D to improve the ratio
Increasing i2・L is the most effective method, but if the outer diameter of the stator core (Do) is kept constant, Di cannot be increased unless the space factor of the stator coil is improved, and the stator winding The inner diameter is determined by wire technology.

On the other hand, when increasing the lamination thickness (L), the length of the rotor ball pawls becomes longer in the case of the Lundell type, and the pawls expand due to centrifugal force during high-speed rotation and may come into contact with the inner diameter of the stator core. ) has a limit to its increase.

Conventional alternators for vehicles generally have 12 poles, and the stacking thickness is set to about 26 to 32 mm when the stator outer diameter is in the range of about 115 to 150 (mm).

In order to further increase the power generation output/mass ratio in the future, it will be effective to increase the rotation speed (N) of the generator, but for the reasons mentioned above,
Increasing the stacking thickness is not a good idea for generators used in wide rotation ranges such as automobiles.

[The problem that the invention attempts to solve]

In order to further increase the power generation output/mass ratio in the future, it will be effective to further increase the number of poles, but since the magnetic path cross-sectional area of the stator core chair and bank core will become smaller, the stator core inner diameter (Dl) and stacking thickness (L) will become smaller. An optimal design is required.

The purpose of the present invention is to increase the stator core inner diameter (Dl) while having a relatively small size and a power generation output/mass ratio.
An object of the present invention is to provide an alternator for a vehicle that can rotate at high speed by optimizing the ratio of the stacking thickness (L) and the stacking thickness (L).

[Means to solve the problem]

In order to achieve the above objective, the stator inner diameter (Di) and stacking thickness (L) are designed to maximize the output/mass ratio when increasing the number of poles from the conventional 12 poles (14 to 18 poles), and the rotor ball The present invention provides a vehicle alternator that can be used at higher rotation speeds by reducing the length of the claws in order to improve the rotational strength of the claws.

[Effect]

In the present invention, when increasing the number of poles within the range of stator core outer diameter φ115 to φ150, the limit is 16 poles, and the ratio of stator inner diameter (DI) to lamination thickness (L) at this time is L/
By setting D in the range of 0.2 to 0.24, the total length of the magnetic circuit can be shortened, and the length of the rotor claw can also be shortened, making it possible to achieve higher speeds and further improve the output/mass ratio. .

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
In the figure, a rotor 1 has a rotor coil 2, which is excited by a direct current supplied from a three-phase full-wave rectifier 4 via a slip ring 3, and is powered by an external drive device (not shown). The IJ 5 is driven, and the rotor 1 fixed to the shaft 6 directly connected to the IJ 5 rotates.

Bearings 7 and 8 that rotatably support the shaft 6 are provided on frames 9 and 10, respectively.

The stator core 11 has a stator coil 12, is held between frames 9 and 10, and is fixed with through bolts 13. 14 and 15 are cooling fans fixed to the rotor 1.

As mentioned above, the rotor 1, which is driven and rotated by external power such as an engine (not shown), is excited by the DC excitation current supplied to the field winding 2, and the claw-shaped magnetic poles 111 on the outer periphery of the rotor are alternately , rotates with an S pole, and a three-phase AC output is generated in the stator coil 12. The 3-phase AC output is 3
The three-phase AC output is converted into DC by being led to a phase full-wave rectifier 4, and a part of it becomes the exciting current for the exciting coil 2, while the other large part is led to an output terminal (not shown) and is externally supplied. It is taken out.

In the conventional Lundem type 12-pole 3-phase AC generator (12V80A class) in this example, the stator outer diameter Do = 1
28m, D+ = 95mn, L = 28m, and L/
D I = 0, 29.

On the other hand, in order to obtain the same output with 16 poles, Do=12
8, Dt = 95m, L = 20m, good < L /
D + = 0, 21.

Since the stack thickness can be reduced and the length of the rotor claws can be shortened by about 30%, the allowable rotation speed has been reduced from 18,000 r/m.
However, with 16 poles, it became possible to increase the speed to 2200 Or/m.

〔Effect of the invention〕

According to the present invention, the output/mass ratio is significantly improved by optimizing the stator inner diameter and the stator stack thickness when the stator is made into 16 poles,
In addition, since high-speed rotation is possible, a significant reduction in size and weight can be expected.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a generator showing one embodiment of the present invention;
The figure is a characteristic diagram showing the effects of the present invention. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Rotor coil, 11... Stator core, 12... Stator coil, Do... Stator core outer diameter, Dl... Stator core inner diameter, Ll...
・Stator core lamination.

Claims (1)

[Claims] 1. A three-phase AC generator for a vehicle having a Lundel-type rotating field pole and a stator core around which an armature winding is wound,
The number of field poles is 16, and the stator core inner diameter dimension D_1,
An alternator for a vehicle, characterized in that a stacking thickness dimension L is set in a relationship of 0.20≦L/D_1≦0.24.