JPH05137297A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To suppress air flowing noise by suppressing an air flow rate of a fan when a rotor is rotated at a predetermined speed or more, and to decrease the air flowing noise by reducing the air flow rate of the fan at the time of low output. CONSTITUTION:A pair of fans 30, 31 at both end sides of pole cores 5, 6 are supported to a rotary shaft 8 side through bearings 32, 33. Main plates 30a, 31a of the fans 30, 31 are opposed to the outer end faces of the cores 5, 6 through axial air gaps. Parts of magnetic fluxes of the cores 5, 6 are branched to the plates 30a, 31a of the fan, and the fans 30, 31 are rotated by a magnetic coupling force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle alternator of a salient-pole rotary type rotor supported by a bracket, and more particularly to a connecting and rotating means for a fan of the rotor.

[0002]

2. Description of the Related Art FIG. 5 is a longitudinal sectional view of a conventional vehicle alternator. In the figure, 1 is a stator, and a stator core 2
And a stator coil 3. 4 is a rotor, which is configured as follows. 5 and 6 are magnetic pole cores of opposite polarities,
Both magnetic pole tooth portions 5a and 6a are alternately projected in the circumferential direction. 7 is an exciting coil held between both magnetic pole cores, 8 is a rotary shaft to which the magnetic pole cores 5 and 6 are fixed, 9 is a pair of slip rings fixed to the rotary shaft 8 via an insulating sleeve, and 10 and 11 are The fan is fixed to the magnetic pole cores 5 and 6.

Next, 12 and 13 are front brackets and rear brackets, which connect the stator core 2 with tightening bolts 14. Due to ventilation, the front bracket 12 has a plurality of intake holes 12a at its end and a plurality of exhaust holes 12b at its outer periphery.
And are provided. Further, the rear bracket 13 is provided with a plurality of intake holes 13a at the end and a plurality of exhaust holes 13b at the outer peripheral part for ventilation. The rotating shaft 8 is a bearing 15
And 16 through front bracket 12 and rear bracket 1
It is supported by 3. Reference numeral 17 denotes a pulley fixed to the rotary shaft 8, and the rotation of the engine is transmitted via a belt to rotate the rotor 4.

A rectifier 18 rectifies the AC voltage induced in the stator coil 3 into a DC voltage and outputs the DC voltage, and a voltage adjuster 19 detects the rectifier output voltage and controls the exciting current to adjust the terminal voltage to a predetermined value. It is a vessel. 20 is a brush holder,
The held brush 21 is pressed against the slip ring 9 to pass an exciting current.

In the above AC generator, when the rotor 4 is rotated, an AC voltage is induced in the stator coil 3 to supply electric power and generate heat. The stator 1 part and the rotor 4 part are cooled by the ventilation generated by the rotation of the fans 10 and 11.

FIG. 6 shows an output current I (full load) with respect to a rotation speed N, a wind noise level P ₁ , a cooling air amount Q ₁ , and an output voltage V and an excitation amount AT of a conventional AC generator, which are constant. The relationship of the temperature rise T ₁ of the generator is shown. When the rotation speed N is high, the cooling air volume Q ₁ with respect to the output current I becomes unnecessarily large, and the wind noise level P ₁ becomes large.

FIG. 7 shows the relationship between the output current I, the wind noise level P ₁ , the cooling air flow Q ₁ , and the generator temperature rise T ₁ with respect to the excitation amount AT when the rotation speed N and the output voltage V are constant. Indicates. Output current I proportional to the amount of excitation of the rotor magnetic pole
Regardless of the above, since the cooling air volume is the same, even at a low excitation amount, the air volume is more than necessary and the wind sound level P ₁ is large.

[0008]

In the conventional vehicle alternator as described above, the fans 10 and 11 are the magnetic pole cores 5,
When it is fixed to No. 6 and the rotation speed becomes high, there is a problem that the amount of cooling air becomes excessive with respect to the output, the wind noise becomes large, and the wind loss becomes large. Further, even at an arbitrary rotation speed, the amount of cooling air is the same regardless of the output in proportion to the amount of excitation, and the amount of cooling air becomes unnecessarily large at low amount of excitation, and there is a problem that wind noise cannot be reduced.

The present invention has been made in order to solve such a problem, and when the rotational speed exceeds a predetermined value, the air volume of the fan is suppressed, wind noise is suppressed, and at low output, the air volume accordingly. The purpose is to obtain a vehicle AC generator that reduces wind noise and wind noise.

[0010]

The vehicle alternator according to the present invention supports the fans on both ends of the magnetic pole core through bearings on the rotary shaft side, and a part of the magnetic flux of the magnetic pole core is the main plate of the fan. A magnetic path for shunting is formed, and the fan is rotated with increased magnetic coupling with respect to the magnetic pole iron core according to the amount of magnetic flux for excitation.

[0011]

In the present invention, the magnetic pole core is excited during power generation, and a part of the magnetic flux passes through the main plate of the fan, so that the fan is magnetically coupled to the magnetic pole core, and the rotational speed of the magnetic pole core is low. When they rotate, they rotate at almost the same speed. As the rotation speed of the magnetic pole core increases, the ventilation resistance of the fan increases and the required drive torque increases, and the fan slips with respect to the rotation speed of the magnetic pole core, resulting in a rotation speed commensurate with the amount of magnetic flux. When the magnetic pole core is at a predetermined speed or higher, the rotation speed of the fan is suppressed, and wind noise in the high rotation speed range is suppressed to a low level. Further, when the output is low, the magnetic flux amount of the magnetic pole core is reduced, so that the magnetic coupling of the fan is reduced, the rotation speed is reduced, and wind noise is reduced.

[0012]

EXAMPLES Example 1. FIG. 1 is a vertical cross-sectional view of an automotive alternator according to the present invention, which includes 1 to 9, 12 to 21 and 5a,
6a, 12a, 12b, 13a and 13b are the same as those in FIG. The front fan 30 is rotatably supported by the rotary shaft 8 via a bearing 32, and the main plate 30a is axially opposed to the end surface of the magnetic pole core 5 with a small air gap. Also,
The rear fan 31 is rotatably supported by the insulating sleeve of the slip ring 9 via a bearing 33, and the main plate 31a is axially opposed to the end face of the magnetic pole core 6 with a small air gap.

FIG. 2 shows the magnetic coupling action of the fans 30, 31 to the magnetic pole cores 5, 6. Magnetic flux Φ from magnetic pole core 5
Enters the stator core 2 through the air gap from the magnetic pole teeth 5a, enters the adjacent magnetic pole teeth 6a again through the air gap, and reaches the magnetic pole core 6 to the magnetic pole core 5. Part of the magnetic flux of the magnetic pole core 5 passes through the air gap from the end face and passes through the main plate 30a of the fan 30. As a result, the fan 30 has the magnetic pole core 5
A magnetic coupling force is applied to the magnetic pole core 5 and the magnetic pole core 5 is rotated according to the rotation. On the other hand, a part of the magnetic flux of the magnetic pole core 6 passes through the air gap from the end face and passes through the main plate 31a of the fan 31.
Thereby, the magnetic coupling force to the magnetic pole core 6 acts on the fan 30, and the fan 30 is rotated according to the rotation of the magnetic pole core 6.

FIG. 3 shows the output current I (full load) with respect to the rotation speed N, the cooling air flow rate Q, the wind noise level P, and the generator current when the output voltage V and the excitation amount AT of the AC generator are constant. The relationship of the temperature rise T is shown in comparison with the conventional FIG. At a low rotation speed of the rotor 4, the fans 10 and 11 are rotated at about the speed of the rotor 4 because the required driving torque is small. As the rotation speed of the rotor 4 increases, the fan 1
The required drive torque of 0 and 11 increases and the slip on the rotor 4 increases, and the rotor 4 is rotated at a rotational speed that is proportional to the magnetic coupling force proportional to the amount of magnetic flux and the required drive torque of the fans 10 and 11. When the rotor 4 has a rotational speed equal to or higher than a predetermined rotational speed, the fans 10 and 11 are controlled to have a suppressed rotational speed, and wind noise in a high rotational speed range is suppressed to be low.

FIG. 4 shows the rotor rotation speed N and the output voltage V
Output current I with respect to the excitation amount AT when
The relationship between the cooling air flow rate Q, the wind noise level P, and the temperature rise of the generator is shown in comparison with FIG. From the relationship of the amount of magnetic flux proportional to the generator output, when the output is low, the amount of magnetic flux decreases, the magnetic coupling force of the fans 10 and 11 also decreases, slipping occurs with respect to the rotational speed of the rotor 4, and the rotational speed decreases, Noise can be reduced.

[0016]

As described above, according to the present invention, the pair of fans on both ends of the magnetic pole core are supported on the rotary shaft side through the bearings, and the main plate of the fan is axially attached to the end face of the magnetic pole core. Since the rotors are opposed to each other via the air gap and are magnetically coupled to each other, when the rotor has a high rotation speed, the fan slips, the rotation speed is suppressed, and wind noise is suppressed. Further, when the output of the generator decreases, the magnetic coupling force of the fan decreases due to the decrease in the amount of magnetic flux, the rotation speed decreases, wind noise decreases, and the extra driving force for rotating the fan is reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a vehicle AC generator according to the present invention.

FIG. 2 is an explanatory diagram showing the flow of magnetic flux of the magnetic pole core and the fan of FIG.

FIG. 3 is a curve diagram showing a relationship between a fan characteristic, a generator output current, and a temperature rise with respect to a rotor rotation speed of FIG. 1.

4 is a curve diagram showing the relationship between the fan characteristic, the generator output current, and the temperature rise with respect to the excitation amount in FIG.

FIG. 5 is a vertical sectional view of a conventional vehicle alternator.

6 is a curve diagram showing the relationship between the fan speed, the generator output current, and the temperature rise with respect to the rotation speed of the rotor of FIG.

FIG. 7 is a curve diagram showing the relationship between the fan characteristic, the generator output current, and the temperature rise with respect to the amount of excitation in FIG.

[Explanation of symbols]

 1 Stator 4 Rotor 5 and 6 Magnetic pole core 7 Excitation coil 8 Rotating shaft 30 and 31 Fan 30a and 32a Main plate 32 and 33 Bearing

Claims (1)

[Claims] 1. A rotor in which a pair of magnetic pole cores of different polarities, which are arranged in a stator and hold an exciting coil and aligned in the axial direction, are fixed to a rotary shaft, and an outer end side of each magnetic pole core. In a vehicle alternator including a pair of arranged fans, each fan is supported on the rotary shaft side via a bearing, and a main plate is opposed to an end face of the magnetic pole core via an air gap in the axial direction. In addition, a part of the magnetic flux of the magnetic pole core passes through the main plate, and the fan is rotated by the magnetic coupling as the magnetic pole core rotates.