JP2000341890A - Rotor of vehicle ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the rotor of a vehicle AC generator which can secure cooling performance of a field coil and achieve size reduction and output increase by employing a new core shape. SOLUTION: This rotor 1 of a vehicle AC generator has a Rundel type core which has a cylindrical part 3a with a field coil 2 wound on its outer circumference, yoke parts 3b provided on the end parts in the axial direction of the cylindrical part 3a and a plurality of claw-shaped pole parts 3c, which are extended from the outer circumference of the yoke part 3b in the axial direction and bent so as to surround the field coil 2 and a cooling fan, which is a ventilating means sending cooling air to the outer circumfernential surface of the field coil 2. An outermost diameter D2 of the field coil 2 is larger than a root diameter D1 of the bent part of the claw-shaped pole part 3c. The ratio of the axial direction length A of the field coil 2 in the circumferential direction width of the root part of the claw-shaped pole part 3c is set in the range of 1-1.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a vehicle alternator mounted on a passenger car, a truck or the like.

[0002]

2. Description of the Related Art In recent years, in order to increase the electric load of a vehicle safety control device and the like, increase the volume of a vehicle interior such as a recreational vehicle, and improve the cooling capacity of the vehicle interior due to an increase in the window area. Due to the increase in the electric load of blowers and the like, the need for increasing the output of vehicle alternators has been increasing.

[0003] Generally, an automotive alternator includes a magnetic circuit comprising a rotor composed of a field coil, a rundle-type iron core (hereinafter simply referred to as an "iron core"), and a stator located on the outer periphery thereof. Unit is configured. In order to increase the output of a vehicle alternator, a method of increasing the number of turns of a field coil to increase the magnetomotive force (ampere turn) of a rotor is generally used. In some cases, the outermost diameter of the concentrically wound field coil is set to be larger than the root diameter of the claw-shaped magnetic pole portion of the iron core.

On the other hand, when a current flows through the field coil, the field coil itself heats up due to Joule heat. Therefore, it is necessary to secure the magnetomotive force by cooling the field coil to suppress an increase in electric resistance. . To cool this field coil, as shown in Japanese Patent Publication No. 59-42546,
It is known that a cooling fan having a diagonal flow blade inclined forward with respect to the rotation direction of a rotor is provided on an axial end face of an iron core to forcibly generate an axial flow. However, if the outermost diameter of the field coil is larger than the root diameter of the claw-shaped magnetic pole portion of the iron core as described above for higher output,
Since the ventilation path of the cooling air flowing through the surface of the field coil is narrowed, the amount of the cooling air is reduced. As a result, the electric resistance of the field coil increases, so the exciting current decreases, the magnetomotive force decreases,
There was a problem that the desired high output could not be achieved. In addition, when the claw pole base diameter is increased to increase the cooling air flow, it is necessary to simultaneously increase the dimensions of other parts so that the magnetic resistance does not increase in a part of the magnetic circuit.
It is difficult to reduce the size of the entire generator.

According to the present invention, in a rotor in which the outermost diameter of the field coil is set to be larger than the base diameter of the claw-shaped magnetic pole portion of the iron core for high output, the field coil is cooled by a new iron core shape. It is an object of the present invention to provide a rotor of a vehicle alternator that achieves miniaturization and high output while ensuring performance.

[0006]

According to the first aspect of the present invention, a cylindrical portion having a field coil wound around the outer periphery thereof, and a substantially circular plate disposed at an axial end of the cylindrical portion. Shaped yoke,
A rundle-type core having a plurality of claw-shaped magnetic pole portions extending in an axial direction from an outer periphery of the yoke portion and surrounding the field coil, and a ventilation means to an outer peripheral surface of the field coil Wherein the outermost diameter of the field coil is set to be larger than the root diameter of the bent portion of the claw-shaped magnetic pole portion, the axial length A of the field coil And the ratio (A / B) of the width B in the circumferential direction of the base portion of the claw-shaped magnetic pole portion is 1 to 1.6. As a result, it is possible to reduce the temperature of the field coil and suppress the increase in the magnetic resistance of the yoke portion, and it is possible to increase the output without increasing the size of the rotor.

According to the invention described in claim 2, according to claim 1
In the above, the Landel-type core is disposed such that a pair of the claw-shaped magnetic pole portions are axially opposed to each other, and the claw tip of one of the claw-shaped magnetic pole portions is opposed to an inner wall surface of the yoke portion of the opposed Landel-type iron core. It is characterized in that it extends more in the axial direction. Thus, the cooling air taken in from one axial end of the outer periphery of the field coil flows while being guided to the other end of the outer periphery of the field coil, so that the cooling performance of the field coil can be improved.

According to the invention described in claim 3, according to claim 1
(2) In the above (2), the ventilation means is a cooling fan provided at an axial end of the Landel-type core and having a mixed flow blade inclined forward in the rotation direction with respect to the axial direction. Thereby, the flow of the cooling air in the axial direction to the field coil, which is a necessary requirement of the present invention, can be forcibly generated.

According to the invention described in claim 4, according to claim 1,
(2) In the above (2), the ventilation means is a cooling fan having a centrifugal blade extending in the axial direction, provided on both sides of the axial end of the Rundel-type iron core, and providing a difference between the pressures generated by the two cooling fans. It is characterized by. Thereby, the flow of the cooling air in the axial direction to the field coil, which is a necessary requirement of the present invention, can be generated.

According to the invention described in claim 5, claim 1 is provided.
In any one of (a) to (d), the ratio of the axial length A of the field coil to the circumferential width B of the base of the claw-shaped magnetic pole portion (A
/ B) is 1.2 to 1.4.
Thereby, higher output can be achieved more stably.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an automotive alternator according to the present invention.

FIG. 1 is an axial sectional view of an automotive alternator according to an embodiment of the present invention. FIG. 2 and FIG.
It is a principal part enlarged view of the rotor of the vehicle alternator of this embodiment. FIG. 4 is a perspective view showing the flow of cooling air on the field coil (however, no fan is shown). 5 to 10
FIG. 8 is a diagram showing an effect on parameters focused on in the present invention.

The rotor 1 of the automotive alternator according to the present embodiment.
A cylindrical portion 3a around which the field coil 2 is wound via the insulating member 4, a disk-shaped yoke portion 3b disposed at an axial end of the cylindrical portion 3a, and a yoke portion 3b A rundle-type core 3 having a claw-shaped magnetic pole portion 3 c extending in the axial direction from the outer periphery and bent so as to surround the field coil 2 is press-fitted and fixed to the shaft 5. In this embodiment, the cylindrical portion 3a is divided into two parts at the center, and the yoke portion 3b and the claw-shaped magnetic pole portion 3c are integrally formed on each cylindrical portion 3a to form a pair of iron cores 3. .

On the axial end surface of the iron core 3, a cooling fan 6,
7 are joined by mechanical processing such as fixing by welding or swaging. The cooling fan 6 arranged on the pulley side has diagonal blades that are inclined forward with respect to the rotation direction of the rotor 1. The cooling fan 7 arranged on the side opposite to the pulley has centrifugal blades extending in the axial direction. Field coil 2
Is wound coaxially with the cylindrical portion 3a via the insulating member 4. In the present embodiment, the field coil 2 is wound so that the central portion along the axial direction rises in the outer diameter direction, and the outermost diameter D2 of this portion is set to 82 mm. Also,
The root diameter D1 of the bent portion of the claw-shaped magnetic pole portion 3c is set to 77 mm, and D1 <D2.

The axial length A of the field coil 2 is 2
The width B in the circumferential direction at the base of the claw-shaped magnetic pole portion 3c of the iron core 3 is set to 23 mm, and their ratio A / B is 1.2. Also, the claw-shaped magnetic pole part 3
c is the inner wall 33b of the yoke portion 3b of the opposed iron core 3.
A stator 10 is disposed on the outer peripheral side of the rotor 1 configured as described above, which extends rearward in the axial direction,
The rotor 1 and the stator 10 are held by frames 8 and 9. The frames 8 and 9 are formed with cooling air intake ports 80 and 90 in the axial direction and discharge ports 81 and 91 in the radial direction, and the cooling fans 6 and 7 take in cooling air from the axial direction.

Thus, the axial intake port 8 on the pulley side
0, the cooling air taken in by the cooling fan 6 has circumferential and axial components as shown by an arrow P in FIG. And the outermost periphery of the field coil 2. At this time, in order not to change the size of the generator, the axial length A of the field coil 2 and the claw-shaped magnetic pole are provided under the condition that the axial length L of the pair of Landel-type cores 3 is not changed. FIG. 5 shows a change in the field coil temperature when the ratio A / B of the circumferential width B of the root portion of the portion 3c is changed. FIG. 6 shows corresponding portions of the dimensions A, B, and L of these portions.

When the axial length A of the field coil 2 is constant, the smaller the circumferential width B of the base of the claw-shaped magnetic pole portion 3c, the smaller the area of the entrance through which the cooling air is taken into the outermost periphery of the field coil. Because of this, the cooling of the field coil 2 is improved,
The temperature drops. When the width B in the circumferential direction of the root portion of the claw-shaped magnetic pole portion 3c is constant, the larger the axial length A of the field coil 2, the larger the surface area of the outermost periphery of the field coil. Since the area is increased, the cooling of the field coil is improved and the temperature is reduced.

Since the tip of the claw-shaped magnetic pole portion 3c extends in the axial direction behind the inner wall 33b of the yoke portion 3b of the opposed iron core 3, it is taken into the outermost periphery of the field coil 2. The cooling air is guided by the inner surface of the claw-shaped magnetic pole portion 3c and flows to the side opposite to the intake direction. Therefore, the taken-in cooling air can be effectively used for cooling the field coil 2.

FIG. 7 shows a change in the magnetic resistance of the yoke portion 3b when the ratio A / B is changed. 8 shows the flow of the magnetic flux φ in the magnetic circuit, and FIG. 9 shows an equivalent circuit of the magnetic circuit. In the equivalent circuit shown in FIG. 9, the magnetic resistance of the yoke portion 3b is Rd, the magnetic resistance of the gap between the rotor 1 and the stator 10 is Rg, the magnetic resistance in the stator core is Rs, and the flowing magnetic flux Is φ, and the magnetomotive force is AT. When the axial length A of the field coil 2 is constant,
As the circumferential width B of the base portion of the claw-shaped magnetic pole portion 3c increases, the magnetic path cross-sectional area perpendicular to the magnetic flux of the radial iron portion 3b increases, so that the magnetic resistance decreases. When the width B in the circumferential direction of the root portion of the claw-shaped magnetic pole portion 3c is constant, the smaller the axial length A of the field coil 2 is, the more the axial length L of the pair of Landel-type cores 3 does not change. Therefore, the magnetic path cross-sectional area of the diameter iron portion 3b similarly increases, so that the magnetic resistance decreases.

That is, as the ratio A / B is larger, the temperature of the field coil 2 is reduced and the output is improved. On the other hand, the magnetic resistance Rd of the yoke portion 3b is increased, so that the output is reduced. I do. Conversely, as the ratio A / B is smaller, the temperature of the field coil 2 rises and acts to lower the output. From the above, in this embodiment, the maximum output can be obtained by selecting an appropriate ratio A / B.

FIG. 10 shows the ratio A /
4 shows the relationship between B and the saturated output of the generator at 5000 revolutions. In FIG. 10, in the rotor of D1 ≧ D2 corresponding to the conventional range indicated by Y, the ventilation path between the outermost periphery of the field coil and the claw-shaped magnetic pole portion is sufficiently wide, so that the axial length of the field coil is large. It is possible to increase the surface area of the outermost periphery of the field coil by increasing the height A, or to reduce the circumferential width B of the root of the claw-shaped magnetic pole portion 3c to increase the entrance area for taking in cooling air. Not only is the effect of cooling the magnetic coil small, but also the disadvantage of increasing the magnetic resistance by increasing the ratio A / B is greater, and the output is reduced.

However, as shown in FIG. 10, the ratio A /
B is a range X1 from 1 to 1.6 which is larger than the conventional range.
(Corresponding to the invention of (1)), it was confirmed that higher output can be achieved than before. Further, the ratio A
By setting / B in the range X2 of 1.2 to 1.4 (corresponding to the invention of claim 5), high output can be stably obtained.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of an automotive alternator according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of an axial cross-sectional view of a rotor of the automotive alternator according to the embodiment.

FIG. 3 is an enlarged view of a main part of the rotor of the vehicle alternator according to the embodiment as viewed in the axial direction.

FIG. 4 is a partial perspective view showing a flow of cooling air near a rotor according to the embodiment.

FIG. 5 is a characteristic diagram showing the effect of the present invention.

FIG. 6 is a diagram showing corresponding portions of dimensions A, B, and L.

FIG. 7 is a characteristic diagram showing the effect of the present invention.

FIG. 8 is a diagram showing the flow of magnetic flux in a magnetic circuit.

FIG. 9 is a diagram showing an equivalent circuit of a magnetic circuit.

FIG. 10 is a characteristic diagram showing the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Field coil 3 Landel type iron core 3a Cylindrical part 3b Yoke part 3c Claw-shaped magnetic pole part 4 Insulating member 5 Shaft 6,7 Cooling fan 8,9 Frame 10 Stator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigenobu Nakamura 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 5H002 AA00 AB08 AC06 AD04 AE07 5H609 BB05 BB13 BB18 PP02 PP07 PP09 QQ02 QQ12 QQ13 RR03 RR16 RR18 RR22 RR24 RR27 RR38 RR44 RR69 RR73 5H619 AA05 AA11 BB06 BB18 PP02 PP05 PP25

Claims (5)

[Claims] A cylindrical portion having a field coil wound around the outer periphery thereof; a substantially disk-shaped yoke portion provided at an axial end of the cylindrical portion; and a shaft extending from an outer periphery of the yoke portion. A claw-shaped core having a plurality of claw-shaped magnetic pole portions extending so as to surround the field coil, and means for ventilating an outer peripheral surface of the field coil; In the rotor of the automotive alternator in which the outermost diameter of the field coil is set to be larger than the root diameter of the bent portion of the portion, the axial length A of the field coil and the root of the claw-shaped magnetic pole portion The ratio of the circumferential width B of the portion (A / B) is 1 to 1.6. 2. The Landel-shaped iron core according to claim 1, wherein the pair of claw-shaped magnetic pole portions are arranged so that the pair of claw-shaped magnetic pole portions face each other in the axial direction, and the claw tip of one of the claw-shaped magnetic pole portions faces each other. A rotor for an automotive alternator, wherein the rotor extends in an axial direction from an inner wall surface of the yoke portion of the iron core. 3. The cooling fan according to claim 1, wherein the ventilation means is provided at an axial end of the Landel type iron core and has a mixed flow blade inclined forward in the rotation direction with respect to the axial direction. A rotor for a vehicular alternator, characterized in that: 4. The cooling fan according to claim 1, wherein the ventilation means is a cooling fan provided on both sides of an axial end portion of the rundle-type core and having centrifugal blades extending in the axial direction. A rotor for a vehicular alternator, wherein a difference is generated in generated pressure. 5. The ratio (A / B) of the axial length A of the field coil to the circumferential width B of a root portion of the claw-shaped magnetic pole portion is set to 1. A rotor for an automotive alternator, wherein the rotor number is 2 to 1.4.