Inductor devices – Core – Laminated type
Reexamination Certificate
1999-06-29
2002-04-09
Donovan, Lincoln (Department: 2832)
Inductor devices
Core
Laminated type
C310S216006
Reexamination Certificate
active
06369687
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an iron core assembly which generally forms a major or essential part of an electric motor, a transformer and the like, and it also relates to a method of producing such an iron core assembly.
2. Description of the Related Art
For example, an iron core assembly of the type mentioned above has been used in a conventional electric motor, as disclosed in Japanese unexamined patent publication (laid-open) No. 9-191588. As shown in
FIGS. 58 and 59
, such a kind of conventional iron core assembly comprises a predetermined number of core members
1
stacked or laminated one over another, each core member
1
being formed of a plurality of core segments 1
a
which are connected together by way of a plurality of thin portions
1
b.
In order to improve winding property or efficiency, the stacked core members
1
in their states as shown in
FIG. 59
are wound with wires
2
by means of a winding machine (not shown), and the respective thin portions
1
b
thereof are then bent properly to form an annular or ring-shaped core assembly as shown in FIG.
58
.
Since a conventional iron core assembly is constructed in the above-described manner, when a ring-shaped iron core assembly is formed, every two adjacent core segments
1
a facing each other through a thin portion
1
b,
and end faces of each edge portion of core segments
1
a
located on opposite ends of each core member
1
, will undesirably produce some rough surface portions and some working size errors during a press punching process. As a result, every two adjacent core segments
1
a
will have to be brought together with an undesirable clearance of several micrometers (&mgr;m) to ten-odd micrometers (&mgr;m) formed therebetween. Due to the existence of such kind of clearances, a magnetic resistance will undesirably be increased, resulting in a problem that the magnetic performance of the iron core assembly is deteriorated.
Further, since each of the core members
1
forming an iron core assembly is usually provided on the surface thereof with a skin layer. Such a kind of skin layer is useful in hampering the passing of magnetic flux therethrough so as to inhibit a possible eddy current loss. For this reason, if there is no such kind of skin layer existing on the end faces of punched portions, an undesired eddy current will occur over the entire area of each end face of each core segment
1
a
in the laminating direction. Because of the occurrence of the eddy current, an undesired iron loss will happen, thus undesirably affecting a desired magnetic performance.
Moreover, on each of the above end faces, since a holding force intended to act against an external force in parallel with the end faces is relatively weak, the iron core assembly as a whole has only low rigidity. In particular, if an electric motor is a type in which a force caused by magnetism exerts on its iron core assembly, it will be difficult to ensure a required strength for the motor.
In addition, since each thin portion
1
b
is bent in a manner such that a circular configuration is formed as a whole, it is difficult to mechanically ensure high precision for an electric motor. Further, since bending treatment has to be performed for several times in order to form the desired circular configuration, some cracks will possibly occur in the thin portions
1
b,
resulting in some problems in which not only the mechanical strength is reduced, but also desired magnetic performance is deteriorated because the cracks will cause an increase in the magnetic resistance of a magnetic circuit.
SUMMARY OF THE INVENTION
In view of the above, the present invention is intended to obviate the above-discussed problems encountered with the conventional iron core assemblies, and has for its object to provide an improved iron core assembly of the character described and a method of manufacture thereof which are suitable for mass production and which are capable of inhibiting a possible increase in the magnetic resistance and a possible occurrence of an eddy current so as to obtain improved magnetic performance, thereby ensuring improved rigidity and increased mechanical precision for the iron core assembly.
Bearing the above object in mind, according to a first aspect of the present a plurality of layers (sometimes referred to herein as “core members”) of plate-shaped core segments having end portions, said core segments disposed in planar succession in each of the plurality of layers; and couplers (sometimes referred to herein as “coupling means”) coupling the end portions of the core segments of a first of the plurality of layers to the end portions of the adjacent core segments of a second of the plurality of layers; wherein said core segments of the first layer are laminated to the core segments of the second layer in such a manner that the end portions of the core segments of the first layer are offset from the end portions of adjacent core segments of the second layer which adjoin each other in a laminating direction that is perpendicular to the planar direction, and wherein said core segments are rotatable relative to each other through said couplers so as to form an enclosed or ring-like configuration.
With this arrangement, it is possible to provide an iron core assembly which is suitable for mas production and can be improved in its magnetic performance and mechanical strength.
In a preferred form of the first aspect of the invention, the coupling means couples together edge portions of those core segments which adjoin each other in the laminating direction of the first and second core members. Thus, it is possible to further improve the magnetic performance and mechanical strength of the iron core assembly.
In another preferred form of the first aspect of the invention, the coupling means comprises: first concave and convex portions respectively formed on a top surface and a back surface of each of the first core segments of the first core member at one end edge portion thereof; and second concave and convex portions respectively formed on a front surface and a bottom surface of each of the second core segments of the second core member at the other end edge portion thereof. The first concave and convex portions are engageable with the second concave and convex portions thereby to couple the edge portions of those core segments which adjoin each other in the laminating direction of the first and second core members.
With this arrangement, it is possible to improve not only the magnetic performance and mechanical strength, but also durability of the iron core assembly against bending operations upon assembling.
In a further preferred form of the first aspect of the invention, the first concave and convex portions are engageable with the second concave and convex portions through clearances. Accordingly, it becomes easy to rotate coupling portions of the iron core assembly.
In a yet further preferred form of the first aspect of the invention, the coupling means comprises: a first hole formed in one end edge portion of each first core segment of the first core member; a second hole in the other end edge portion of each second core segment of the second core member; and a pin member passing through the first and second holes in the laminated first and second core segments in the laminating direction of the first and second core members in such a manner as to allow relative rotation of the first and second core segments.
With this arrangement, it is possible not only to improve the magnetic performance and mechanical strength, but also further expedite rotation of the iron core assembly upon assemblage thereof, thus ensuring improved assembling precision.
In a still further preferred form of the first aspect of the invention, each first core segment of the first core member has one end face at least partially formed into a convex arc-shaped configuration and the other end face at least partially formed into a concave arc-shaped configuration, with the convex arc-shaped one end face of each f
Akita Hiroyuki
Anamura Takashi
Azuma Ken-Ichi
Miyake Nobuaki
Nakahara Yuji
Burns Doane , Swecker, Mathis LLP
Donovan Lincoln
Nguyen Tuyen
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