Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-03-26
2003-02-18
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S051000, C310S052000, C310S058000, C310S261100
Reexamination Certificate
active
06522046
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a vehicular AC generator having a salient-pole-rotating stator supported by brackets.
(2) Description of the Related Art
A conventional general vehicular AC generator will be described with reference to
FIG. 1
to FIG.
4
. In the figures, a reference numeral
1
represents rear brackets of the generator each having an inlet opening
1
a
and an outlet opening
1
b.
A reference numeral
2
represents a rectifier,
3
is a brush holder having a regulator
3
a
, and
4
is a rotor consisting of a pair of cores
4
a
1
and
4
a
2
and is supported and fixed to a rotating shaft
5
. A reference symbol
4
b
designates a plurality of trapezoidal-shaped claws functioning as magnetic poles periodically protruding from the edges of the outer peripheries of the cores
4
a
1
and
4
a
2
. The claws
4
b
of the core
4
a
1
and the claws
4
b
of the core
4
a
2
are alternately arranged in such a way that each of the claws belonging to one of the pair of cores is arranged in a concave portion between adjacent two of the claws belonging to the other one of the pair of cores. A reference numeral
6
is a coil field accommodated within both of the cores
4
a
1
and
4
a
2
. Reference symbols
7
a
and
7
b
designate centrifugal fans respectively attached to the side surfaces of the cores
4
a
1
and
4
a
2
. Reference numeral
8
represents a stator arranged on the outer periphery of the rotor
4
, and consisting of a core
8
a
and coil ends
8
b
and
8
c
. Reference numeral
9
is a front bracket having an inlet opening
9
a
for sucking outside air and an outlet opening
9
b
for exhausting air. Reference numerals
10
a
and
10
b
represent bearings for supporting the rotating shaft
5
.
Next, in the vehicular AC generator constructed as above, a cooling channel will be described. First, outside air is sucked from the rear bracket
1
through the inlet opening
1
a
to cool the rectifier
2
and the regulator
3
a
. Then, the cooling air is strongly sucked by the centrifugal fans
7
a
to be bent so as to cool the coil end
8
b
of the rear side of the stator
8
, and is exhausted from the outlet opening
1
b.
On the other hand, outside air from the front bracket
9
is flown through the inlet opening
9
a
and is separated to be flown into two channels, i.e., on one hand, is sucked by the centrifugal fans
7
b
to be bent so as to cool the coil end
8
b
of the front side of the stator
8
and is exhausted from the outlet opening
1
b
, and on the other hand, to cool the coil field
6
and then is flown to the rear side and is exhausted from the outlet opening
1
b.
In such a general type of the conventional vehicular AC generator, since the gap between the outer periphery surface of the shoulder portion of each of the claws
4
b
and the coil end
8
b
or
8
c
is small, and since the inner surfaces of the coil ends
8
b
and
8
c
are irregular, there is a problem in that ragged sound caused by cutting wind (interfering sound between the coils
4
a
1
and
4
a
2
and the coil ends
8
b
and
8
c
) is generated.
A prior art AC generator to solve such a problem is disclosed in, for example, Japanese Laid Open Patent Application (Kokai) No. 1-74163/89. This prior art AC generator will be described with reference to FIG.
5
.
FIG. 5
, the same parts as those in the above-described conventional general AC generator are denoted by the same reference symbols, and the explanation thereof are omitted here. Reference numeral
11
designate tapered portions of the outer periphery surfaces of the shoulders of the claws
4
b
each having a sloping surface against the end surface in the shaft direction.
By forming the tapered portions
11
in the claws
4
b
as above, the gap between each tapered portion
11
of the outer periphery surface of the claw
4
b
and each of the coil ends
8
b
and
8
c
is gradually increased in the direction toward the end surface, resulting in that the interference sound generated, during the rotation of the cores
4
a
1
and
4
a
2
, between each of the cores
4
a
1
and
4
a
2
and each of the coil ends
8
b
and
8
c
is reduced.
In the prior art vehicular AC generator shown in
FIG. 5
, although the interference noise between each of the cores
4
a
1
and
4
a
2
and each of the coil ends
8
b
and
8
c
can be reduced by the tapered portions
11
in the outer periphery surfaces of the claws
4
b
, however, the gap between each of the centrifugal fans
7
a
and
7
b
and each of the coil ends
8
b
and
8
c
is still kept to be narrow in order to ensure a cooling efficiency of the coil ends
8
b
and
8
c
. Because the gap between each of the centrifugal fans
7
a
and
7
b
and each of the coil ends
8
b
and
8
c
is so narrow, there is a problem in that noise sound caused by cutting wind is generated between each of the coil ends
8
b
and
8
c
and each of the centrifugal fans
7
a
and
7
b
during the rotation of the centrifugal fans
7
a
and
7
b.
SUMMARY OF THE INVENTION
An object of the present invention is to resolve the above-mentioned problems, and to provide a vehicular AC generator in which noise sound caused by cutting wind by the rotation of centrifugal fans can be reduced.
Another object of the present invention is to provide a vehicular AC generator in which the cooling efficiency of coil ends of a stator by means of the centrifugal fans is not lowered even when the outer diameters of the centrifugal fans are made small.
Still another object of the present invention is to provide a vehicular AC generator in which noise sound caused by cutting wind by cores can be reduced by making the lowering of the output current due to the decrease of the outer diameters of centrifugal fans to be smaller.
According to the first aspect of the present invention, there is provided, for achieving the above object, a vehicular AC generator in which at least one of a pair of front and rear fans attached to the both ends of a core of a rotor has a outer diameter in the range between 85% and 96% of an outer diameter of the core.
According to the second aspect of the present invention, there is provided a vehicular AC generator having a side plate fixed to the end portion of one of the fans and having an outer diameter smaller than the outer diameter of the fan.
According to the third aspect of the present invention, there is provided a vehicular AC generator in which each of the tapered portions formed in the claws is provided in at least the front side of the direction of rotation in the width of the circumferential direction of each claw.
As stated above, according to the first aspect of the present invention, since the diameter of the fan is made to be in the range between 85% and 96% of the outer diameter of the core, noise caused by the fans themselves can be reduced, and the sound caused by cutting wind generated between the fans and the coil ends during the rotation of the fans can be reduced.
Further, according to the second aspect of the present invention, since the side plate is attached to the fan, the reduction of the amount of the cooling wind due to the decrease of the outer diameter of the fan can be prevented.
Still further, according to the third aspect of the present invention, since each of the tapered portions is provided in at least the front side of the direction of rotation in the width of the circumferential direction of each claw, the lowering of the output current due to the decrease of the outer diameter of the rotor core can be prevented.
The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.
REFERENCES:
patent: 3749953 (1973-07-01), Baumann et al.
patent: 4115030 (1978-09-01), Inagaki et al.
patent: 4186317 (1980-01-01), Sisk
patent
Adachi Katsumi
Ikeda Ryuichi
Mullins Burton S.
Sughrue & Mion, PLLC
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