Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1989-03-07
1990-09-25
Skudy, R.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 45, 310 59, H02K 900
Patent
active
049595709
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a motor cooling system, and, more particularly, to a motor cooling system advantageously applicable to cooling a spindle motor for a machine tool.
BACKGROUND ART
Self-cooling type motors are usually equipped with an individual fan motor at the rear end thereof, but a spindle motor for rotatively driving the spindle (tool spindle) of a machine tool cannot be satisfactorily cooled by a self-cooling fan, because the spindle motor operates over a wide speed range of from a low speed to a high speed.
Accordingly, as shown in FIG. 3, the conventional spindle motor is provided, on the outer circumference of a stator 1, with an oil jacket 3 having helical groove 31 formed in the outer circumference thereof and covered with an outer sleeve 4, to form a path extending from an inlet opening 30 formed on the outer sleeve 4 to an outlet opening 32 formed on the outer sleeve 4, and a cooling liquid is passed through the path as indicated by arrows F.sub.1 and F.sub.2 to cool the oil jacket 3.
The conventional oil jacket cooling system cannot efficiently cool the stator, because this is an indirect cooling system which removes heat transferred, from the stator heated by the heat generated by the coils, projecting portions 10 of the to the oil jacket.
Furthermore, the conventional cooling system cannot remove heat generated in the rotor 2 and in end rings 20 attached respectively to opposite ends of the rotor 2 on the drive shaft 5.
The present invention provides a means which eliminates the disadvantages of the conventional motor cooling system, and is capable of removing heat generated in the rotor and the stator coils.
DISCLOSURE OF THE INVENTION
As exemplified in FIG. 2, a stator 1 is processed by molding to apply a coating layer 11 of a synthetic resin over projecting portions 10 of stator coils projecting from the opposite ends of a stator core and the resin coats a core of the stator, nozzles 9 are inserted through a housing H in the interior of the spindle motor driven by drive shaft 5, a cooling liquid (or oil) L is sprayed by the nozzles 9 over the stator coils and the end rings 20 of the rotor 2, and the cooling liquid L is drained through outlet openings 92.
Thus, both the rotor and the stator coils coated with the synthetic resin can be directly cooled to increase the coefficient of heat convection and the coefficient of cooling, whereby the motor can be efficiently cooled.
Since the cooling liquid can be applied directly to the heat generating members, namely, the stator coils, the rotor and the end rings, the heating of the motor can be remarkably reduced compared with the heating of the conventional motor, and the motor can be made more compact.
Efficient cooling makes it possible to reduce the size of the spindle motor, and increase the output capacity by increasing the current supply, to thereby widen the output range of the spindle motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a motor employing a motor cooling system in a first embodiment according to the present invention;
FIG. 2 is a schematic sectional view of a motor employing a motor cooling system in a second embodiment according to the present invention; and
FIG. 3 is a schematic sectional view of a motor employing a conventional motor cooling system.
BEST MODE OF CARRYING OUT THE INVENTION
EXAMPLE 1
FIG. 1 shows a spindle motor having a stator length of 346 mm and a stator outside diameter of 180 mm, to which the present invention is applied. A stator 1 having stator coils with partly projecting portions 10 which project from the opposite ends of a stator core and is coated with a layer of a synthetic resin 11 by molding and is finished by machining the layer of the synthetic resin. A rotor 2 fixedly provided at opposite ends thereof with end rings 20 each coated with a synthetic resin coating 21 is combined with the stator 1 to construct a motor having a drive shaft 5. The motor is sealed in a watertight fashion by fitting an oil jacket 3 on the outer circ
REFERENCES:
patent: 2188398 (1940-01-01), Bernard
patent: 3158009 (1964-11-01), Rayner
patent: 3217193 (1965-11-01), Rayner
patent: 3241331 (1966-03-01), Endress
patent: 3479541 (1969-11-01), Robinson
patent: 3648085 (1972-03-01), Fujii
Hayashi Yoshiyuki
Nakamura Kosei
Fanuc Ltd.
Skudy R.
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