Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-06-15
2004-05-25
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S058000
Reexamination Certificate
active
06740995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automotive alternator mounted to, for example, an automotive vehicle, and, in particular, to an automotive alternator mounting a brush, rectifier and regulator.
2. Description of the Related Art
FIG. 19
is a cross section showing a conventional automotive alternator for use in an automobile.
FIG. 20
is a perspective view of the conventional alternator. The conventional automotive alternator shown in the figures includes, a case
3
constructed from an aluminum front bracket
1
and rear bracket
2
, a shaft
5
with a pulley
4
fixed on one end thereof provided inside the case
3
, a claw-pole rotor
6
fixed to the shaft
5
, fans
7
a
,
7
b
fixed on respective axial end surfaces of the rotor
6
, a stator core
17
fixed inside the case
3
, a stator coil
18
received in slots of the stator core
17
, a stator
8
constructed from the stator core
17
and the stator coil
18
, a slip-ring
9
fixed on the other end of the shaft
5
for supplying electric current to the rotor
6
, a pair of brushes
10
for slidingly contacting the slip-ring
9
, a brush holder
11
for receiving the brushes
10
, a rectifier
12
electrically connected to the stator coil
18
for rectifying an alternating current (ac) produced in the stator coil
18
into a direct current (dc), a heat sink
13
fitted to the brush holder
11
, and a regulator
14
attached to the heat sink
13
for adjusting the alternating voltage produced in the stator coil
18
.
A connector
22
for insertion in an external plug (not shown) is disposed in the vicinity of the regulator
14
. A regulator assembly
30
includes the regulator
14
, brush holder
11
and connector
22
.
The rotor
6
includes a rotor coil
15
for flowing an electric current to generate magnetic flux and a pole core
16
which houses the rotor coil
15
and forms magnetic poles in accordance with a magnetic flux. The fans
7
a
,
7
b
for cooling are provided on respective axial end surfaces of the pole core
16
.
The stator
8
includes the stator core
17
, through which passes a rotating magnetic field in accordance with the rotor
6
, and the stator coil
18
which flows an alternating current output in accordance with the rotating magnetic field, and the stator coil
18
forms coil ends
19
at both axial ends of the stator core
17
.
FIG. 21
is a perspective view of the regulator assembly
30
. Moreover,
FIG. 22
is a drawing showing front, top and side views of the regulator assembly
30
. In the conventional regulator assembly
30
, the regulator
14
and brush holder
11
are disposed so as to overlap in an axial direction of the shaft
5
. The connector
22
is disposed relative to the regulator
14
and brush holder
11
at a location on a plane including the regulator
14
and brush holder
11
and orthogonally intersecting the shaft
5
and rotated a predetermined angle in a circumferential direction, and such that an opening thereof faces toward the outside. Ventilating holes
30
a
are provided at both sides of the brush holder
11
.
FIG. 23
is a perspective view of the rectifier assembly
31
in which a rectifier
12
is assembled with a circuit board
29
. Furthermore,
FIG. 24
is a front view of a conventional rear bracket assembly.
FIG. 25
is a cross section taken along the line C—C shown by the arrows in FIG.
24
. In the figures, the rectifier
12
includes diodes
20
mounted on an approximately C-shaped heat sink
21
, and the rectifier
12
is assembled with a similarly roughly C-shaped circuit board
29
to give the rectifier assembly
31
. The rectifier assembly
31
is assembled to the rear bracket
2
such that the circuit board
29
is positioned at the middle of the dynamo-electric generator (alternator). Further, the rectifier assembly
31
is secured by bolts
28
as a fixing means. In this case, since the rectifier assembly
31
makes a approximate C-shape, it is possible to have a space in a C-shaped opening. Next, the regulator assembly
30
is inserted and assembled in this space and, as shown in
FIGS. 24 and 25
, the rear bracket assembly is assembled. Moreover, an angle between the two bolts
28
, being a standard governing the size of the plate-shaped heat dissipating heat sink
21
, is 210 degrees.
FIG. 26
is a front view of a conventional rear bracket.
FIG. 27
is a drawing of a conventional alternator viewed from a rear side thereof. A plurality of openings E (intake holes) formed in the rear bracket are opened at locations corresponding to the roughly C-shaped rectifier assembly
31
. Moreover, an opening G (intake hole) is opened at a location corresponding to the regulator assembly
30
.
In an automotive alternator constructed as above, as shown in
FIG. 19
, cooling air flows into the case
3
from the openings E of the case
3
in accordance with rotation of the fan
7
b
which rotates together with rotation of the rotor
6
. This cooling air flows as shown by the arrow a and cools the heat sink
21
and diodes
20
. Then, this cooling air is flowed in an outside radial direction (centrifugal direction) by the fan
7
b
and is discharged to the outside from an opening F. Moreover, cooling air also flows into the case
3
in accordance with rotation of the fan
7
b
from an opening G and this cooling air flows as shown by the arrow &bgr; and cools the heat sink
13
and power transistors of the regulator
14
. Then, this cooling air is flowed in an outside radial direction by the fan
7
b
and is discharged to the outside from an opening H.
An S terminal, so-called because it relates to sensing, and an L terminal, so-called because it relates to a lamp, are provided in the connector
22
and these terminals are connected to various portions in an automotive vehicle via an external plug (not shown). The S terminal is used to monitor battery voltage and the L terminal is used to flow an initial exciting current and for lighting a lamp (not shown) when there is a generating abnormality such as an over generation, over discharge and the like.
In a conventional automotive alternator constructed as above, the regulator assembly
30
is disposed in the empty space of the C-shaped opening portion of the approximately C-shaped rectifier assembly
31
. Namely, the rectifier assembly
31
and regulator assembly
30
are provided in a same plane orthogonally intersecting the shaft
5
. Thus, the size of the heat sink
21
of the rectifier
12
is limited by the regulator assembly
30
. However, if the size of the heat sink
21
of the rectifier
12
is increased, cooling characteristics of the rectifier
12
are improved and durability may also be increased along with the increase in performance. Also, the connector
22
is disposed, relative to the regulator
14
fixed to the heat sink and the brush holder, in the same plane orthogonally intersecting the shaft
5
and adjacent in a circumferential direction. Since there is a difference in ventilating resistance between the portions where the heat sink and connector
22
are disposed, the rectifying characteristics of the cooling air ventilating the regulator assembly
30
are obstructed. Consequently, the cooling characteristics of the entire rear bracket assembly, including the rectifier
12
, are degraded. Moreover, wind noise increases due to a ventilating unbalance at the intake side.
SUMMARY OF THE INVENTION
The present invention aims to solve the above problems with the conventional art and an object of the present invention is to provide an automotive alternator in which a ventilating resistance unbalance is improved, surface area of a heat dissipating plate of a rectifier is enlarged to improved cooling characteristics of the rectifier and reduce noise, performance is high, and durability and quality are high.
In order to achieve the above object, according to one aspect of the present invention, there is provided an automotive alternator comprising:
a shaft supported in a case so as to be capable of rotating;
a rotor housed in the case and compr
Asao Yoshihito
Oohashi Atsushi
Mitsubishi Denki & Kabushiki Kaisha
Sughrue & Mion, PLLC
Waks Joseph
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