Pumps – Motor driven – Pump within rotary working member
Reexamination Certificate
1998-10-01
2001-05-22
Yuen, Henry C. (Department: 3747)
Pumps
Motor driven
Pump within rotary working member
C417S366000, C310S156030
Reexamination Certificate
active
06234767
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotor having permanent magnets and mechanism for cooling the same. More particularly, the invention relates to a rotor having a plurality of permanent magnets embedded in adjacent to a field core of the rotor for, e.g., a power generator, and a construction for cooling such a rotor.
2. Prior Art
A rotor has been known, e.g., from Japanese Patent Laid-Open No. 8-107639, which comprises providing spaces for embedding permanent magnets at the position in adjacent to the outer circumference, laminating field core pieces, and embedding the permanent magnets. However, such a rotor having gaps provided cannot sufficiently prevent the leakage of the magnetic flux of magnetic circuit. Due to the radiation heat from the armature, which increases the temperatures of the field core and/or permanent magnets embedded into the field core and due to insufficient cooling of the permanent magnets, sufficient output cannot be obtained in the case of the rotor having a large output. In such a rotor, with the operation of the power generator, the field core is heated by the radiation heat from the armature, such an increase in the temperature of permanent magnets also decrease in output of the power generator.
In the case of embedding permanent magnets in to field core in such a conventional rotor, the whole size of rotor becomes large, the magnet flux is frequently leaked and, thus, the output of the power generator is decreased. Furthermore, due to the radiation from the armature, the temperatures of the field core and the permanent magnet embedded therein are increased. Due to insufficient cooling of the field core and, in particular of the permanent magnet, the decrease in the output due to the heat cannot be avoided
Moreover, such a rotor also is disadvantageous in that the cooling air within the field core insufficiently flows, leading to a reduced cooling efficiency and, thus, increase in the output of the power generator cannot be expected.
As shown in
FIGS. 19A and 19B
, we have developed a lamination of the armature core for a rotating field core type power generator and filed as Japanese Patent Application No. 9-269046. The lamination construction of an armature sheets according to this application is a lamination (D
1
−D
n
) of the armature sheets G in which the armature core sheets has a circular shape in order to store a field core of the power generator within the armature, which can revolves within the armature core, each armature is formed by punching plurality of V-shaped or trapezoid caulking portions K on the outer circumference, characterized in that V-shape or trapezoid caulking portions K are formed by punching the portions in adjacent to the teeth portions B projected on the inner circumference of the armature core D residing on the radial line from the axis O of the field core, and at the same time, when the armature sheets D are laminated to be a laminate construction (D
1
−D
n
), said caulking portions K are fitted to tightly communicate the armature sheets D. (1) When the field core revolves at high speed within the armature, the teeth portions have an influence upon magnetic flux which frequently changes, resulting in vibration. The vibration due to the influence of the magnetic flux causes the magnetic route formed on the teeth portions to be irregular. Since V-shape or trapezoid caulking portions K are formed by punching the portions in adjacent to the teeth portions B, the loss of the magnetism caused by the irregular magnetic route can be prevented. Consequently, (2) uncomfortable feeling can be avoided and, at the same time, noise can be reduced. (2) When the length of the caulking portions K are punched along the radial line not shown from the axis of the field core, the magnetic route becomes uniform. Consequently, the loss of the magnetism can be prevented.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotor for a power generator having permanent magnets which has a simple and a small-sized construction, can reduce the leakage of magnetic flux, suppress an increase in the temperature of the filed core and permanent magnets, and has a large amount of output.
Another object of the present invention is to provide a cooling mechanism for cooling a rotor having permanent magnets which can effectively cool the field core and permanent magnets whereby a decrease in output of the power generator due to an increase in their temperature can be suppressed as little as possible, so as to improve a decrease in the output of the power generator due to an increase in the temperature of the field core making up the rotor or the permanent magnets embedded therein by the radiation heat from the winding of the armature as seen in the prior art.
According to the first aspect of the present invention, there is provided a rotor having permanent magnets formed by laminating a plurality of permanent magnets embedded in storage pores, characterized in that each permanent magnet is inserted in each of said storage pore so as to form gaps at the both ends of the storage pore of the field core, thereby to form air paths for cooling air.
In the first aspect of the present invention, it is preferable that said storage pores formed in adjacent to the outer frame is formed as long pores, rectangle permanent magnets are embedded into each of the pores at the center portion thereof, and means for positioning the permanent magnets are placed in the gaps formed on the both ends of each pores.
Further, it is also preferable in the first aspect of the present invention that said means for positioning the permanent magnet is formed so that both ends thereof are longer than the middle portion to place difference in shape of the storage pores.
Moreover, it is also preferable in the first aspect of the present invention that said means for positioning the permanent magnet position the permanent magnet is formed by embedding a non-magnetic substance into part of the gaps.
According to the second aspect of the present invention there provided a mechanism for cooling a rotor having permanent magnets formed by laminating a plurality of field core sheets to form a field core, embedding a plurality of permanent magnets into the field core, and fixing the field core by means of a pair of end plates having a plurality of wings on the outer surface thereof so as to generate the flow of cooling air toward the armature winding, characterized by
forming air paths for cooling air by providing gaps between each of the inner surface of the end plate and the outer surface of the field core, and
also forming air paths for cooling air by placing air paths in the axis direction in contact with each of the permanent magnets on both ends of the permanent magnet, and placing an inlet and an outlet of the cooling air on each of said air paths in such a manner that the cooling air enters one end plate and exits the other end plate via each of said air paths.
In the second aspect of the present invention, it is preferable that concave grooves each having an air inlet in which an outer frame side is closed and an axis core side is opened, and concave portions each having an air outlet in which an axis core side is closed and an outer frame side is opened are alternatively placed on the inner surface of the outer edge of the end plates, a concave portion on one end plate is position opposite to a concave groove on the other end plate so as to clamp the said field core and, at the same time, the air paths formed on both ends of the permanent magnets perforated into the field core is fixed by said pair of the end plates on both sides of the field core opposite to the concave portion and the concave groove of the said pair of the end plates, and according to the rotation of the rotor, by means of a fan effect caused by the outside wing, the projected portions around said concave grooves and the projected portions around said concave portions formed radially, the cooling air is spouted through the gaps
Mizuno Yasumasa
Takeda Masanobu
Denyo Co., Lmtd.
Gimie Mahmoud M
Liniak Berenato Longacre & White
Yuen Henry C.
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