Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-02-22
2004-08-10
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S052000, C310S059000, C310S06000A
Reexamination Certificate
active
06774514
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2000-049842, filed Feb. 25, 2000; and Japanese Patent Application No. 2000-207443, filed Jul. 7, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a totally enclosed type driving electric motor which is used, for example, in a railway vehicle (particularly, an electric railcar) or the like.
A driving electric motor for a railway vehicle is ventilated and cooled so as to prevent a temperature at a driving time from being increased over a preset value. That is, in the driving electric motor, a cooling wind is taken into an internal portion from an external portion so as to prevent an abnormality in a function of an insulating material and each of members from being generated due to a heat generated by energizing at a time of using the motor, and each of the members within the motor is cooled.
In the general motor, an open air is taken into the motor in accordance with a rotation of a ventilation fan attached to a rotary shaft within the motor. The sucked open air flows through the inner portion of the motor. Accordingly, a heat generating portion is ventilated and cooled.
However, when the open air is taken into the motor so as to perform a cooling operation, dusts contained in the open air are attached to the inner portion of the motor. Accordingly, the inner portion of the driving electric motor is spoiled. In the driving electric motor soiled in the inner portion, a heat radiating efficiency is reduced and a function of the motor is reduced. Therefore, it is necessary to dissemble the driving electric motor at a fixed period so as to take care thereof such as cleaning or the like. Since a lot of labor is required for the cleaning operation, it is required to improve in view of maintenance.
Further, a sound generated by rotation of a ventilating fan for communicating the open air is leaked to an external portion from a port through which the air blows to the external portion from the inner portion of the driving electric motor. The rotation sound of the ventilating fan becomes a large sound in an area having a great number of rotation (in a high speed operation area). Accordingly, it is required to improve the sound.
In order to improve the problems, development of a totally enclosed type driving electric motor has been promoted in recent years. Since the totally enclosed type driving electric motor does not flow the open air into the motor, the inner portion of the motor is not spoiled for a long period. Accordingly, the totally enclosed type driving electric motor is not required to be dissembled, and it is possible to save a maintenance.
Further, since the totally enclosed type driving electric motor does not require a ventilating fan, it is possible to avoid the sound generated by the rotation of the fan, and it is possible to achieve a widely low sound.
FIG. 18
is a cross sectional view showing a first embodiment of a structure of a conventional totally enclosed type driving electric motor.
FIG. 18
shows a state in which a rotary axis of a shaft provided in the totally enclosed type driving electric motor is horizontal.
FIG. 18
shows an upper half portion of the totally enclosed type driving electric motor in a side cross section parallel to the rotary axis of the shaft, and omits a lower half portion substantially symmetrical to the rotary axis of the shaft.
The conventional totally enclosed type driving electric motor
1
is provided with a frame
2
formed in a cylindrical shape. A cylindrical stator core
3
is mounted to an inner peripheral surface (interior surface) of the frame
2
.
A multiplicity of grooves are formed on an inner peripheral surface of the stator core
3
in an axial direction. A stator coil
4
is mounted to the grooves.
A bearing bracket
6
supporting a bearing
5
is provided in one end portion of the frame
2
.
A housing
8
supporting a bearing
7
is provided in the other end portion of the frame
2
.
The bearing
5
and the bearing
7
rotatably support a shaft
9
of a rotor. The shaft
9
is coaxially provided with the stator core
3
.
Further, a lubricating agent such as a lubricating grease or the like for smoothening a rotational operation of the shaft
9
is charged in the bearing
5
and the bearing
7
.
A rotor core
10
is provided in a center portion of the shaft
9
. A rotor
11
is mounted to a multiplicity of grooves formed on an outer peripheral surface (outer surface) of the rotor core
10
.
A rotating force generated in the rotor core
10
is transmitted to a drive apparatus by an end portion
9
a
of the shaft
9
.
A multiplicity of cooling fins
2
a
and
2
b
are provided on the outer peripheral surface of the frame
2
and a side surface of the other end portion of the frame
2
. The cooling fins
2
a
and
2
b
radiate heat generated within the motor to the open air. Further, a multiplicity of cooling fins
6
a
are also provided on a side surface of the bearing bracket
6
.
FIG. 19
is an outer appearance view showing a mounting state of the conventional totally enclosed type driving electric motor
1
structured in the manner mentioned above.
FIG. 19
is a view obtained by seeing the totally enclosed type driving electric motor
1
from a direction of the rotary axis of the shaft
9
provided in the totally enclosed type driving electric motor
1
and from a side of the bearing bracket
6
.
The totally enclosed type driving electric motor
1
is fixed and supported to a truck frame
12
by supporting arms
2
c
and
2
d
provided in a part of the frame
2
.
A drive apparatus constituted by a gear (a large gear)
13
, a pinion (a small gear)
14
and a gear box
15
is provided in adjacent to the totally enclosed type driving electric motor
1
.
A rotating force of the totally enclosed type driving electric motor
1
is transmitted to the pinion
14
by an end portion
9
a
of the shaft
9
, and rotates an axle
16
a
of a tire wheel
16
through the gear
13
meshed with the pinion
14
. Accordingly, a vehicle
17
runs on rails
18
.
In the totally enclosed type driving electric motor
1
, the heat generated in the stator coil
4
and a rotor bar
11
corresponding to a heat generating portion is discharged to the open air from the frame
2
and the shaft
9
via the stator core
3
and the rotor core
10
. Further, in the totally enclosed type driving electric motor
1
, the air within the motor is heated by the heat generated in the stator coil
4
and the rotor bar
11
. Further, the heat of the air within the motor is transmitted to the frame
2
, the bearing bracket
6
and the housing
8
and radiated to the open air. Accordingly, in the conventional totally enclosed type driving electric motor
1
, the whole of the apparatus becomes in a heated state.
On the other hand, since a self-ventilation cooling motor is structured such that a cooling wind directly flows through the heat generating portion, the heat in the heat generating portion is discharged to the external portion by the cooling wind at a high rate, so that a temperature of the other portions than the heat generating portions such as the frame, the bearing bracket, the shaft and the like are hard to be increased.
Accordingly, in the conventional totally enclosed type driving electric motor
1
, the temperature of the bearing bracket
6
, the housing
8
, the shaft
9
and the like are widely increased due to the heat within the motor in comparison with the self-ventilation type cooling driving electric motor. Therefore, in the conventional totally enclosed type driving electric motor
1
, a lubricating grease is quickly deteriorated due to the heat and the lubricating service life becomes short, so that it is necessary to early replace the grease.
The totally enclosed type driving electric motor
1
is structured such as to save the maintenance by preventing the inner portion of the motor from being spoiled so
Ibusuki Katsuhiko
Kinoshita Tsutomu
Kondo Minoru
Matsuoka Ko-ichi
Nagayama Takashi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Gonzalez Julio C.
Kabushiki Kaisha Toshiba
Nguyen Tran
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