Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-08-16
2001-09-11
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S208000, C310S254100, C310S049540
Reexamination Certificate
active
06288462
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a stator of an alternating current generator.
FIG. 11
is a sectional view showing a conventional alternating current generator. In the drawing, numerals
1
and
2
are a front bracket and a rear bracket made of aluminum constituting a case of the generator, and numeral
3
is a shaft provided inside the case and one end of the shaft is fixed in a pulley
4
, and numeral
5
is a rotor of lundel-type fixed in the shaft
3
, and numeral
6
is fans fixed in both sides of the rotor
5
, and numeral
8
is a stator fixed in an inner wall of the case, and numeral
9
is a slip ring fixed in the other end (the opposite side of the end in which the pulley
4
is fixed) of the shaft
3
and the slip ring supplies a current to the rotor
5
, and numeral
10
is a pair of brushes for sliding on the slip ring
9
, and numeral
11
is a brush holder for receiving the brushes
10
, and numeral
12
is a commutator electrically connected to the stator
8
and the commutator commutates alternating current output generated in the stator
8
into direct current output, and numeral
13
is a heat sink fixed in the brush holder
11
, and numeral
14
is a regulator bonded to the heat sink
13
and the regulator controls an alternating current output voltage from the stator
8
.
The rotor
5
comprises a rotor coil
15
for generating a magnetic flux by the flow of a current and pole cores
16
which sandwich the rotor coil
15
and form magnetic poles by the magnetic flux, and the pole cores
16
comprise a pair of a first pole core body and a second pole core body with the bodies engaging alternately.
The stator
8
comprises a stator core
17
and a stator coil
18
in which a conductor is wound on the stator core
17
and an alternating current voltage is generated by a change in the magnetic flux from the rotor coil
15
with rotation of the rotor
5
.
In the alternating current generator shown in
FIG. 11
, by supplying a current from a battery (not shown) to the rotor coil
15
through the brushes
10
and the slip ring
9
, the magnetic flux is generated and the first pole core body is magnetized in a north pole and the second pole core body is magnetized in a south pole. On the other hand, the pulley
4
is driven by an engine (not shown) and the rotor
5
rotates with the shaft
3
and thereby, a rotating magnetic field generated in the pole cores
16
is given to the stator coil
18
and an alternating current voltage is generated in the stator coil
18
by electromagnetic induction. The alternating current output generated in the stator coil
18
is commutated into direct current by the commutator
12
and also is controlled by the regulator
14
and is charged to the battery.
FIG. 12
is an enlarged perspective view of the stator of the alternating current generator shown in
FIG. 11
, and
FIG. 13
is a detail view showing a structure of a neutral connection portion of the stator of FIG.
12
.
A conductor constituting the stator coil
18
of the stator
8
is formed of a round conductor and comprises a receiving portion
18
a
received inside slots formed in the stator core
17
and a coil end portion
18
b
protruding to both sides of the stator core
17
. Also, when the stator coil
18
is connected in a star in order to configure a circuit of a three-phase alternating current generator, a neutral connection portion
20
is formed in order to couple three conductor ends to make a neutral point and further output lines for sending the alternating current output generated in the stator coil
18
to the commutator
12
are included. Also, in order to recover output from a neutral voltage generated in the neutral point, an output outgoing line may be together coupled to the neutral connection portion
20
and in this case, four conductor ends are connected at the neutral connection portion
20
.
Tough pitch copper is used in a conductor of the stator coil
18
and conventionally, the neutral connection portion
20
is bonded by soldering. Also, the soldered neutral connection portion
20
is coated with an insulating tube
22
and is inclined to the side of the coil end portion
18
b
in order to improve resistance to vibration and is fixed by varnish through the insulating tube
22
.
Also, as a method of neutral connection, a method for fixing conductor ends using a bundling member and contacting to couple a different type of metal with good conductivity to the conductor end surface is disclosed in the Unexamined Japanese Patent Application No. Hei 7-115743.
The neutral connection portion of the stator of the conventional alternating current generator is configured as described above, and when solder is used as a bonding member of the neutral connection portion
20
, there was a problem that a bonded portion is opened due to heat deterioration. Also, when Pb-containing solder is used in order to improve heat resistance of the solder, there were an environmental problem and a problem of a decrease in workability associated with an increase in melting point of the bonding member. Further, since a solidification shape is not stable in the solder, there is a possibility that a problem occurs in insertion into the insulating tube
22
. Furthermore, for bonding using the solder, connection resistance increases due to deterioration of the solder, so that there was a problem that an increase in temperature of the bonded portion is accelerated and deterioration of the bonded portion is promoted.
Moreover, since bond strength is low in the bonding using the solder, a large area of the solder bonded portion is required and also, for fastening to a coil end portion, an insulating tube is always necessary for insulation and there was a problem that fastening strength is low in the fastening through the insulating tube.
Also, as a method of neutral connection, methods such as fusing and swaging have been proposed, but there was a problem of increase in a part count since a “terminal” to be used as a connection medium is required in any case and further, there was a problem of increase in a part kind since a terminal for connection corresponding to a sectional area of a conductor is required in order to bundle several conductors. Further, when the terminal is connected as a medium, a size of outer diameter of a neutral connection portion includes a thickness of the terminal, so that the diameter of the neutral connection portion increases and accordingly a diameter of the insulating tube to be fitted for insulation of a connection portion also increases, with the result that there was a problem that the conductors in the vicinity of the connection portion inside the insulating tube are difficult to fix and hold.
SUMMARY OF THE INVENTION
The invention is implemented to overcome such problems, and it is an object of the invention to obtain a stator of an alternating current generator having a neutral connection portion with high reliability capable of improving bonding workability of the neutral connection portion.
A stator of an alternating current generator according to the invention comprises: a stator core having plural slots, a stator coil in which conductors are wound in the slots, and a neutral connection portion of the stator coil provided in a coil end portion formed in one end of the stator core, and plural conductor ends acting as a neutral point of the stator coil are bundled in the neutral connection portion and each of the conductor ends is substantially engaged with at least other plural conductor ends to be bonded by arc welding and a melt bonded portion of the neutral connection portion is formed in a substantially hemispherical shape in which the side of the bonded conductor ends is a base.
Also, the melt bonded portion by the arc welding of the neutral connection portion has a base area larger than or equal to the total sectional area of conductors to be bonded.
Further, plural conductors constituting the neutral connection portion are bonded by the arc welding with the conductors twisted.
Furthermore, solder coating is appli
Asao Yoshihito
Higashino Kyoko
Tanaka Kazunori
Mitsubishi Denki & Kabushiki Kaisha
Perez Guillermo
Ramirez Nestor
Sughrue Mion Zinn Macpeak & Seas, PLLC
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