Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-11-14
2002-12-17
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S168000, C310S216006, C310S254100, C310S261100
Reexamination Certificate
active
06495941
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dynamo-electric machine applicable to a motor and a generator and, more particularly, to a dynamo-electric machine that is directly coupled to a crankshaft of an internal combustion engine to be ideally used for starting the internal combustion engine and for generating power.
2. Description of the Related Art
As a dynamo-electric machine used for such a type of application, there is a claw pole synchronous motor disclosed in, for example, Japanese Patent No. 2641166.
FIG. 12
is a schematic configuration diagram showing the claw pole synchronous motor described in, for example, Japanese Patent No. 2641166.
Referring to
FIG. 12
, the conventional claw pole synchronous motor is configured using a flywheel
3
attached to a crankshaft
2
projecting from an end surface of an engine main body
1
, and equipped with rotating field poles
4
provided on an outer peripheral portion of the flywheel
3
, a field coil
5
disposed on an inner peripheral side thereof, and a starter coil
6
disposed on an outer peripheral side thereof. The rotating field poles
4
are provided integrally at regular intervals on the outer peripheral portion of the flywheel
3
, and formed of first pole cores
7
having many claws
7
a,
second pole cores
8
having many claws
8
a
positioned between the claws
7
a,
and a nonmagnetic ring
9
coupling the first and second pole cores inside the distal ends of the claws
7
a
and
8
a.
The field coil
5
is constructed by winding a conductor around a field core
10
secured to the end surface of the engine main body
1
via a member (not shown) that shuts off a magnetic field, and housed in a recessed section
3
a
provided in the outer peripheral portion of the flywheel
3
such that its outer peripheral surface is close to and opposes the inner peripheral surface of the rotating magnetic pole
4
. Very small gaps are provided between the opposing surfaces of the field core
10
and the flywheel
3
and between the opposing surfaces of the field coil
10
and the rotating field pole
4
. The starter coil
6
is constructed by winding a conductor around an annular starter core
11
composed of many stacked steel plates, the inner surface thereof being close to and opposing the outer peripheral surface of the rotating field pole
4
. Numerous slots
11
a
are formed at regular intervals in the inner periphery of the starter core
11
. A three-phase coil is constructed by installing conductors in these slots
11
a
by three-phase distributed winding.
In the claw pole synchronous motor configured as described above, passing Direct currents through the field coil
5
generates a magnetic flux. The magnetic flux causes the claws
7
a
of the pole core
7
to be magnetized to the north polarity, and the claws
8
a
of the pole core
8
to be magnetized to the south polarity. Supplying a three-phase alternating current to the starter coil
6
causes a rotating magnetic field to be applied to the rotating field pole
4
to rotationally drive the flywheel
3
, that is, the crankshaft
2
, thereby starting the engine.
Stopping the supply of the three-phase alternating current to the starter coil
6
causes the rotating magnetic field formed by the rotating field pole
4
to be applied to the starter coil
6
instead. This generates induced electromotive force in the starter coil
6
, so that the motor acts as a generator.
As another dynamo-electric machine used for such a type of applications, there is an inductor type generator disclosed in, for example, Japanese Examined Patent Publication No. 2-43029.
FIG. 13
is a perspective view showing the inductor type generator disclosed in, for example, Japanese Examined Patent Publication No. 2-43029, and
FIG. 14
is a development front view showing an essential section of the inductor type generator shown in FIG.
13
.
The conventional inductor type generator shown in FIG.
13
and
FIG. 14
has many inductor magnetic poles
15
provided at predetermined pitches in a circumferential direction on the outer peripheral surface of a flywheel
14
attached to a crankshaft
13
directly coupled to an engine. The flywheel
14
provided with the inductor magnetic poles
15
constitutes a rotor. The starter
16
is equipped with a plurality of pole cores
17
arranged in the circumferential direction of the flywheel
14
. Bottom ends of pole cores
17
face against the inductor magnetic poles
15
with small gaps provided therebetween, while top ends thereof are secured to a cover plate
19
a
of a case
19
via a stator yoke
18
. Each armature coil
20
is wound around two pole cores
17
, while each excitation coil
21
is wound around each of the pole cores
17
.
In the inductor generator configured as described above, passing Direct currents through the excitation coils
21
causes the excitation coils
21
to be energized. The excitation coils
21
cause the pole cores
17
, two each, to be magnetized so that they are magnetized in the opposite directions to each other, and paired pole cores
17
wrapped with the same armature coil
20
are magnetized to have opposite polarities to one another. Accordingly, at a certain moment, a magnetic circuit
22
indicated by a dashed line in
FIG. 14
is created, and when the flywheel
14
rotates to cause the inductor magnetic poles
15
to move for an angle corresponding to the pitch of the pole cores
17
, a magnetic circuit
23
indicated by a chain line in
FIG. 14
is formed. A magnetic flux passing through these magnetic circuits
22
and
23
is interlinked with the armature coils
20
, and the direction of the magnetic flux passing through the magnetic circuit
22
is opposite to the direction of the magnetic flux passing through the magnetic circuit
23
. Changes in the magnetic fluxes induce electromotive forces in the armature coils
20
, causing the motor to act as a generator.
On the other hand, in this conventional inductor generator, the excitation coils
21
are energized by a battery (not shown) to form the magnetic circuits
22
and
23
alternately. At the same time, currents that reverse the directions thereof alternately pass through the armature coils
20
disposed to be interlinked with the magnetic circuits
22
and
23
as the flywheel
14
rotates or the inductor magnetic poles
15
rotate. This causes the armature coils
20
to be subjected to torque in a rotational direction. The armature coils
20
make up a stator, so that it cannot rotate; the inductor magnetic poles
15
are subjected to a reactive force thereof. Thus, the flywheel
14
provided with the inductor poles
15
rotates to provide the motor for starting the engine.
The rotating field pole
4
serving as the rotor of the conventional claw pole synchronous motor is constructed by the first pole cores
7
having many claws
7
a,
second pole cores
8
having many claws
8
a
positioned between the claws
7
a,
and the nonmagnetic ring
9
coupling the two types of pole cores inside the distal ends of the claws
7
a
and
8
a.
Hence, the rotor has the complicated structure, presenting a problem in that it exhibits unsatisfactory strength against a centrifugal force during high-speed revolution, leading to a possibility of damage to the rotor during a high-speed operation.
Furthermore, in the conventional inductor generator, each of the armature coils
20
wraps two pole cores
17
. This requires a longer coil with consequent higher coil resistance, meaning an increased copper loss when currents pass through the armature coils
20
, with resultant deteriorated efficiency.
SUMMARY OF THE INVENTION
The present invention has been made with a view toward solving the problems described above, and it is an object of the present invention to provide a dynamo-electric machine that acts as a motor and a generator, features higher strength against a centrifugal force during high-speed revolution so as to protect a rotor from damage during the high-speed revolution, and also features lower coil resistance of arma
Nguyen Tran
Sughrue & Mion, PLLC
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