U.S. patent application number 09/962344 was filed with the patent office on 2002-10-31 for magneto-generator, method of manufacturing the same and resin molding die assembly for manufacturing the same.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Baba, Shinji, Uemura, Fumito, Umezaki, Tomokazu.
Application Number | 20020158532 09/962344 |
Document ID | / |
Family ID | 18980356 |
Filed Date | 2002-10-31 |
United States Patent
Application |
20020158532 |
Kind Code |
A1 |
Uemura, Fumito ; et
al. |
October 31, 2002 |
Magneto-generator, method of manufacturing the same and resin
molding die assembly for manufacturing the same
Abstract
A magneto-generator, a method of manufacturing the same and a
resin molding die for manufacturing the same. In the
magneto-generator, a guard ring is omitted with the performance of
the magneto-generator being enhanced. The magneto-generator is
manufactured by making use of a resin molding die (21) having an
outer peripheral surface (21d) to be positioned in opposition to an
inner peripheral surface of a flywheel (11) and projections (21a)
provided in the outer peripheral surface (21d) for holding a
plurality of magnets (12) at predetermined positions, respectively.
The magnets (12) are positioned and held stationarily at
predetermined positions by the aforementioned projections,
respectively, and spaces defined between the resin molding die (21)
and the inner peripheral surface of the flywheel (11) are filled
with a resin. After hardening of the resin, the resin molding die
(21) is detached from the flywheel (11).
Inventors: |
Uemura, Fumito; (Tokyo,
JP) ; Baba, Shinji; (Tokyo, JP) ; Umezaki,
Tomokazu; (Tokyo, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
|
Family ID: |
18980356 |
Appl. No.: |
09/962344 |
Filed: |
September 26, 2001 |
Current U.S.
Class: |
310/153 ;
310/74 |
Current CPC
Class: |
H02K 15/03 20130101;
H02K 1/2786 20130101; Y10T 29/49009 20150115; Y10T 29/49012
20150115; Y10T 29/4981 20150115; Y10T 29/49879 20150115 |
Class at
Publication: |
310/153 ;
310/74 |
International
Class: |
H02K 021/22; H02K
007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 27, 2001 |
JP |
2001-132327 |
Claims
What is claimed is:
1. A magneto-generator, comprising: a bowl-shaped flywheel; a
plurality of magnets mounted on an inner peripheral surface of said
flywheel; a resin filled around each of said individual magnets for
fixedly securing said magnets to said flywheel as integral parts
thereof; and a generator coil disposed within said bowl-shaped
flywheel in opposition to said magnets for generating electric
power under the action of electromagnetic induction brought about
through cooperation with said magnets; wherein said
magneto-generator is manufactured by making use of a resin molding
die having an outer peripheral surface to be positioned in
opposition to an inner peripheral surface of said flywheel and
projections provided in said outer peripheral surface for holding
said plurality of magnets at predetermined positions, respectively,
positioning said magnets at said predetermined positions,
respectively, filling said resin in spaces defined between said
resin molding die and said flywheel, and detaching said resin
molding die from said flywheel.
2. A method of manufacturing a magneto-generator which includes a
bowl-shaped flywheel, a plurality of magnets mounted on an inner
peripheral surface of said flywheel, a resin filled around each of
said individual magnets for fixedly securing said magnets to said
flywheel as integral parts thereof, and a generator coil disposed
within said bowl-shaped flywheel in opposition to said magnets for
generating electric power under the action of electromagnetic
induction brought about through cooperation with said magnets, said
manufacturing method comprising: a resin filling step in which a
resin molding die having an outer peripheral surface to be
positioned in opposition to an inner peripheral surface of said
flywheel and projections provided in said outer peripheral surface
for holding said plurality of magnets at predetermined positions,
respectively, is employed for filling said resin in spaces defined
between said resin molding die and said flywheel while holding said
magnets at said predetermined positions, respectively; and a die
detaching step of detaching said resin molding die from said
flywheel.
3. A method of manufacturing a magneto-generator according to claim
2, wherein each of said projections of said resin molding die
extends continuously and axially from a given position at a side of
said magnet substantially up to an open end of said flywheel.
4. A method of manufacturing a magneto-generator according to claim
2, wherein said resin molding die includes a magnet sucking/holding
mechanism disposed interiorly of said die for securing fixedly said
magnets on said outer peripheral surface of said resin molding die
upon filling of said resin.
5. A resin molding die for manufacturing a magneto-generator which
is comprised of a bowl-shaped flywheel, a plurality of magnets
mounted on an inner peripheral surface of said flywheel, a resin
filled around each of said individual magnets for fixedly securing
said magnets to said flywheel as integral parts thereof, and a
generator coil disposed within said bowl-shaped flywheel in
opposition to said magnets for generating electric power under the
action of electromagnetic induction brought about through
cooperation with said magnets, said resin molding die comprising:
an outer peripheral surface to be positioned in opposition to an
inner peripheral surface of said flywheel; and projections provided
in said outer peripheral surface for holding said plurality of
magnets at predetermined positions, respectively.
6. A resin molding die for manufacturing a magneto-generator
according to claim 5, wherein each of said projections extends
continuously and axially from a given position at a side of said
magnet substantially up to an open end of said flywheel.
7. A resin molding die for manufacturing a magneto-generator
according to claim 5, wherein said resin molding die includes a
magnet sucking/holding mechanism disposed interiorly of said die
for securing fixedly said magnets on said outer peripheral surface
of said resin molding die upon filling of said resin.
8. A resin molding die for manufacturing a magneto-generator
according to claim 5, further comprising: a ring-like projection
formed around said outer peripheral surface of said die for
supporting said magnets at one end thereof.
9. A resin molding die for manufacturing a magneto-generator
according to claim 5, further comprising: a plurality of discrete
projections disposed around said outer peripheral surface of said
die for supporting said plurality of magnets at one ends thereof,
respectively.
10. A resin molding die for manufacturing a magneto-generator
according to claim 5, wherein said resin molding die is designed to
cooperate with an outside molding die disposed around said resin
molding die for supporting an open end of said flywheel.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a
magneto-generator (also referred to as the magnetoelectric
generator) for generating electric power under the action of
electromagnetic induction taking place between magnets mounted on a
flywheel and an armature winding during rotation of the flywheel
and a method of manufacturing the magneto-generator. More
particularly, the present invention is concerned with a method of
manufacturing a flywheel provided with a plurality of magnets
mounted on an inner peripheral surface of the flywheel.
[0003] 2. Description of Related Art
[0004] For having better understanding of the concept underlying
the present invention, description will first be made of a
conventional flywheel type magneto-generator by reference to FIGS.
6, 7 and 8, in which FIG. 6 is a front view of a rotor of a
conventional flywheel type magneto-generator disclosed, for
example, in Japanese Patent Publication No. 81437/1994
(JP-A-6-81437), FIG. 7 is a sectional view of the same taken along
the line VI-VI shown in FIG. 6 as viewed in the direction indicated
by arrows, and FIG. 8 is a perspective view of a guard ring of the
conventional flywheel type magneto-generator disclosed in the
publication mentioned above. Referring to the figures, reference
numeral 1 denotes a flywheel implemented in a substantially
bowl-like shape (hereinafter also referred to as the bowl-shaped
flywheel only for the convenience of description), reference
numeral 2 denotes four magnets mounted on the peripheral wall of
the flywheel 1 with equidistance between adjacent ones in the
circumferential direction, numeral 3 denotes a guard annulus or
ring of a substantially cylindrical shape which is adapted to be
closely fit onto the inner surfaces of the magnets 2 which are
disposed in a substantially annular array, numeral 4 denotes resin
blocks filled at both sides and between the adjacent ones of the
magnets 2 for fixedly securing the magnets 2 and the guard ring 3
to the flywheel 1 in a so-called integrated structure, and
reference numeral 5 denotes a hub or boss formed in the flywheel 1
at a center portion of the bottom wall for coupling the rotor to a
rotatable shaft (not shown).
[0005] In the rotor of the conventional magneto-generator
implemented in the structure described above, four magnets 2 are
disposed with equidistance therebetween on the inner peripheral
surface of the flywheel 1 with the guard ring 3 being tightly fit
onto the magnets 2 on the inner side thereof, wherein the voids or
spaces defined between the inner peripheral surface of the flywheel
1 and the outer peripheral surface of the guard ring 3 are filled
with the resin 4. In this manner, the magnets 2 and the guard ring
3 can fixedly be secured to the flywheel 1 through the medium of
the resin 4.
[0006] FIG. 9 is a perspective view showing another example of the
guard ring employed in the conventional magneto-generator. Further,
FIG. 10 is a perspective view showing the state in which magnets
are disposed on the guard ring shown in FIG. 9. As can easily be
seen from FIG. 9, the guard ring 13 shown therein is destined for
use in the magneto-generator in which a large number of magnets 2
are employed with the width thereof in the circumferential
direction being reduced when compared with the structure shown in
FIG. 8. Further, the guard ring 13 shown in FIG. 9 is formed with
projections 13a for holding the magnets 2 equidistantly relative to
one another.
[0007] In the conventional magneto-generator of the structure
described above, the positions of the individual magnets 2 are
sustained by means of the projections 13a formed in the guard ring
13 until the magnets 2 disposed on the flywheel 1 have been fixedly
secured to the flywheel 1. In recent years, however, there has
arisen a demand for sparing or omitting the guard ring 3 or 13 with
a view to reducing the number of parts constituting the
magneto-generator. In this conjunction, it is further noted that
the presence of the guard ring 3 or 13 increases the distance
between a generator coil of the stator (not shown) and the magnets
2, which is unfavorable for realization of enhanced performance of
the magneto-generator. For this reason, the guard ring 3 or 13
should preferably be omitted.
SUMMARY OF THE INVENTION
[0008] In the light of the state of the art described above, it is
an object of the present invention to provide a magneto-generator
of an improved structure which allows the guard ring to be unused
or omitted while reducing the manufacturing cost and which can
enhance the performance of the magneto-generator by diminishing the
distance between the magnets and the generator coil.
[0009] Another object of the present invention is to provide a
method of manufacturing the magneto-generator of the structure
mentioned above.
[0010] Yet another object of the present invention is to provide a
resin molding die assembly which can be used for manufacturing the
above-mentioned magneto-generator.
[0011] In view of the above and other objects which will become
apparent as the description proceeds, there is provided according
to a first aspect of the present invention a magneto-generator
which includes a bowl-shaped flywheel, a plurality of magnets
mounted on an inner peripheral surface of the flywheel, a resin
filled around each of the individual magnets for fixedly securing
the magnets to the flywheel as integral parts thereof, and a
generator coil disposed within the bowl-shaped flywheel in
opposition to the magnets for generating electric power under the
action of electromagnetic induction brought about through
cooperation with the magnets, wherein the magneto-generator is
manufactured by making use of a resin molding die having an outer
peripheral surface to be positioned in opposition to an inner
peripheral surface of the flywheel and projections provided in the
outer peripheral surface for holding the plurality of magnets at
predetermined positions, respectively, positioning the magnets at
the predetermined positions, respectively, filling the resin in
spaces defined between the resin molding die and the flywheel, and
detaching the resin molding die from the flywheel.
[0012] By virtue of the arrangement described above, there can be
implemented the magneto-generator of an improved structure which
allows the guard ring is omitted and which thus allows the
manufacturing cost to be reduced while ensuring enhanced
performance owing to decrease of the distance between the magnets
and the generator coil.
[0013] Further, there is proposed according to a second aspect of
the present invention a method of manufacturing a magneto-generator
which includes a bowl-shaped flywheel, a plurality of magnets
mounted on an inner peripheral surface of the flywheel, a resin
filled around each of the individual magnets for fixedly securing
the magnets to the flywheel as integral parts thereof, and a
generator coil disposed within the bowl-shaped flywheel in
opposition to the magnets for generating electric power under the
action of electromagnetic induction brought about through
cooperation with the magnets. The manufacturing method includes a
resin filling step in which a resin molding die having an outer
peripheral surface to be positioned in opposition to an inner
peripheral surface of the flywheel and projections provided in the
outer peripheral surface for holding the plurality of magnets at
predetermined positions, respectively, is employed for filling the
resin in spaces defined between the resin molding die and the
flywheel while holding the magnets at the predetermined positions,
respectively, and a die detaching step of detaching the resin
molding die from the flywheel.
[0014] Owing to the features described above, the guard ring can be
omitted from the magneto-generator and hence the manufacturing cost
of the magneto-generator can be reduced while the performance of
the generator can be enhanced owing to the shortened distance
intervening between the magnets and the generator coil of the
magneto-generator.
[0015] In a preferred mode for carrying out the method described
above, each of the projections of the resin molding die should be
so provided as to extend continuously and axially from a given
position at a side of the magnet substantially up to an open end of
the flywheel.
[0016] With the arrangement described above, the magnets can
securely be sustained in the circumferential direction, and the
magnets can be held stationarily in a stabilized manner without
incurring undesirable rotation or displacement of the magnets.
Thus, the manufacturing efficiency can significantly be
enhanced.
[0017] In another preferred mode for carrying out the method
described above, the resin molding die may include a magnet
sucking/holding mechanism disposed interiorly of the die for
securing fixedly the magnets on the outer peripheral surface of the
resin molding die upon filling of the resin.
[0018] With the arrangement described above, the magnets can be
held stationarily in a much stabilized state. Thus, the
manufacturing efficiency can further be enhanced.
[0019] Furthermore, there is proposed according to a third aspect
of the present invention a resin molding die for manufacturing a
magneto-generator which is comprised of a bowl-shaped flywheel, a
plurality of magnets mounted on an inner peripheral surface of the
flywheel, a resin filled around each of the individual magnets for
fixedly securing the magnets to the flywheel as integral parts
thereof, and a generator coil disposed within the bowl-shaped
flywheel in opposition to the magnets for generating electric power
under the action of electromagnetic induction brought about through
cooperation with the magnets. The resin molding die includes an
outer peripheral surface to be positioned in opposition to an inner
peripheral surface of the flywheel, and projections provided in the
outer peripheral surface for holding the plurality of magnets at
predetermined positions, respectively.
[0020] Owing to the arrangement of the resin molding die assembly
described above, the guard ring can be omitted from the
magneto-generator and hence the manufacturing cost of the
magneto-generator can be reduced. Moreover, the performance of the
magneto-generator can be enhanced owing to the decreased distance
intervening between the magnets and the generator coil of the
magneto-generator.
[0021] In a mode for carrying out the invention, each of the
projections should preferably extend continuously and axially from
a given position at a side of the magnet substantially up to an
open end of the flywheel.
[0022] With the arrangement described above, the magnets can
steadily be held in the circumferential direction without incurring
rotation or the like displacement of the magnets. Thus, the magnets
can be held in a much stabilized state, which in turn means that
the manufacturing efficiency of the magneto-generator can
correspondingly be enhanced.
[0023] In another mode for carrying out the invention, the resin
molding die should preferably include a magnet sucking/holding
mechanism disposed interiorly of the die for securing fixedly the
magnets on the outer peripheral surface of the resin molding die
upon filling of the resin.
[0024] With the arrangement described above, the magnets can be
held more positively, whereby the manufacturing efficiency can
significantly be increased.
[0025] In yet another mode for carrying out the invention, the
resin molding die for manufacturing the magneto-generator may
further include a ring-like projection formed around the outer
peripheral surface of the die for supporting the magnets at one end
thereof.
[0026] In still another mode for carrying out the invention, the
resin molding die for manufacturing the may further include a
plurality of discrete projections disposed around the outer
peripheral surface of the die for supporting the plurality of
magnets at one ends thereof, respectively.
[0027] In a further mode for carrying out the invention, the resin
molding die may be so designed as to cooperate with an outside
molding die disposed around the resin molding die for supporting an
open end of the flywheel.
[0028] The arrangements mentioned above contribute to holding
stationarily the magnets at respective predetermined positions with
high reliability during the resin molding process.
[0029] The above and other objects, features and attendant
advantages of the present invention will more easily be understood
by reading the following description of the preferred embodiments
thereof taken, only by way of example, in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In the course of the description which follows, reference is
made to the drawings, in which:
[0031] FIG. 1 is a perspective view showing a rotor of a
magneto-generator according to an embodiment of the present
invention;
[0032] FIG. 2 is a perspective view showing a resin molding die
assembly which can be employed for manufacturing the rotor shown in
FIG. 1;
[0033] FIG. 3 is a view showing the state in which magnets are
magnetically attracted stationarily onto a resin molding die
assembly;
[0034] FIG. 4 is a perspective view showing another example of the
resin molding die assembly;
[0035] FIG. 5 is a perspective view showing yet another example of
the resin molding die assembly;
[0036] FIG. 6 is a front view of a rotor of a conventional flywheel
type magneto-generator;
[0037] FIG. 7 is a sectional view of the same taken along the line
VI-VI shown in FIG. 6 and viewed in the direction indicated by
arrows;
[0038] FIG. 8 is a perspective view showing a guard ring employed
in the conventional flywheel type magneto-generator;
[0039] FIG. 9 is a perspective view showing another example of the
guard ring employed in the conventional magneto-generator; and
[0040] FIG. 10 is a perspective view showing the state in which
magnets are disposed on the guard ring shown in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] The present invention will be described in detail in
conjunction with what is presently considered as preferred or
typical embodiments thereof by reference to the drawings. In the
following description, like reference characters designate like or
corresponding parts throughout the several views.
[0042] FIG. 1 is a perspective view showing a rotor of a
magneto-generator according to an embodiment of the present
invention. Referring to FIG. 1, the rotor of the magneto-generator
according to the instant embodiment of the invention includes a
bowl-shaped flywheel 11 which is composed of a cylindrical
peripheral wall 11a and a bottom portion 11b formed integrally with
the cylindrical peripheral wall 11a so as to close one open end of
the cylindrical peripheral wall 11a. Formed at a center of the
bottom portion 11b of the flywheel 11 is a hub or boss 15 which is
employed for coupling the rotor to a rotatable shaft such as e.g. a
crank shaft of an internal combustion engine (not shown). Further,
twelve magnets 12 each having an arcuate cross-section are disposed
on the inner peripheral surface of the cylindrical peripheral wall
11a of the flywheel 11 equidistantly relative to one another as
viewed in the circumferential direction. Resin 14 is filled in the
spaces formed between the individual magnets 12 and at both sides
thereof so that the magnets 12 are embedded flush in the resin 14,
whereby the magnets 12 are fixedly secured at respective
predetermined positions in the axial direction as well as in the
radial direction.
[0043] FIG. 2 is a perspective view showing a resin molding die
assembly which can be employed for manufacturing the rotor shown in
FIG. 1. The resin molding die assembly according to the instant
embodiment of the invention is generally comprised of two major
portions, i.e., a rotor inside molding die 21 and a rotor outside
molding die 22. Provided in the outer peripheral surface of the
rotor inside molding die 21 are projections 21a for sustaining or
holding the magnets 12 in the circumferential direction while
projections 22a for holding the magnets 12 in the axial direction
are provided in the rotor outside molding die 22. Each of the
projections 21a extends continuously in the axial direction from a
given position at a side of the magnet (not shown) substantially up
to the open end of the bowl-shaped flywheel 11. Further,
through-holes 21b for sucking and holding fixedly the magnets 12
are formed in the rotor inside molding die 21 at positions where
the magnets 12 are to be positioned. To this end, a magnet
sucking/holding mechanism (not shown) is disposed in the interior
of the rotor inside molding die 21 for sucking and holding
stationarily the magnets 12 by making use of e.g. a negative
pressure or vacuum. By way of example, the magnet sucking/holding
mechanism mentioned above may be constituted by suction or vacuum
nozzle devices connected hydraulically to a vacuum source such as a
vacuum pump for sucking the magnets 12 under vacuum by way of the
through-holes 21b to thereby hold stationarily the magnets at
respective positions. Alternatively, the magnet sucking/holding
mechanism may be constituted by a magnetic holding device or the
like which is designed to magnetically attract the magnets 12 for
thereby holding them stationarily at respective positions under
magnetic attracting force. In FIG. 3, there is shown the state in
which the magnets 12 are fixedly disposed in the resin molding die
assembly under vacuum or magnetic attraction.
[0044] The flywheel rotor is manufactured by making use of the
resin molding die assembly implemented in the structure described
above in the manner described below. The flywheel to be mounted
with magnets, the rotor inside molding die 21 and the rotor outside
molding die 22 are mutually superposed such that an end face 21c of
the rotor inside molding die 21 is brought into contact with the
bottom portion 11b of the flywheel 11, an outer peripheral surface
21d of the rotor inside molding die 21 is disposed in opposition to
the inner peripheral surface of the flywheel 11, and an end face
22b of the rotor outside molding die 22 bears on the opening edge
portion 11c of the flywheel 11, whereby spaces to be filled with
resin are formed, respectively. These spaces are then filled with
the resin 14. Thus, the magnets 12 are fixedly secured at
predetermined positions, respectively, after the resin has been
hardened. Subsequently, the resin molding dies are detached from
the flywheel 11.
[0045] FIG. 4 is a perspective view which shows another example of
the resin molding die assembly. In the case of this resin molding
die assembly, the projection provided in the rotor outside molding
die 22 for holding stationarily the magnets in the axial direction
is formed in an annular or ring shape such as exemplified by a
ring-like projection 122a.
[0046] FIG. 5 is a perspective view which shows yet another example
of the resin molding die assembly. In the case of this resin
molding die assembly, projections provided in the rotor outside
molding die 22 for holding the magnets in the axial direction are
each formed in an arcuate shape, as exemplified by the projections
222a.
[0047] In the magneto-generator implemented in the structure
described above, the magneto-generator includes the bowl-shaped
flywheel 11, a plurality of magnets 12 mounted on an inner
peripheral surface of the flywheel 11, the resin 14 filled around
each of the individual magnets 12 for fixedly securing the magnets
12 to the flywheel 11 as integral parts thereof, and a generator
coil disposed within the bowl-shaped flywheel 11 in opposition to
the magnets 12 for generating electric power under the action of
electromagnetic induction brought about through cooperation with
the magnets 12. The magneto-generator is manufactured by making use
of the resin molding die 21 having the outer peripheral surface 21d
to be positioned in opposition to the inner peripheral surface of
the flywheel 11 and projections 21a provided in the outer
peripheral surface 21d for holding the plurality of magnets 12 at
predetermined positions, respectively, positioning the magnets 12
at the predetermined positions, respectively, filling the resin 14
in spaces defined between the resin molding die 21 and the flywheel
11, and detaching the resin molding die 21 from the flywheel 11
after the resin has been hardened. By virtue of the arrangement
described above, there can be manufactured the magneto-generator of
an improved structure which allows the guard ring usually employed
in this type conventional magneto-generator to be omitted and hence
the manufacturing cost to be reduced. In addition, the performance
of the magneto-generator can significantly be enhanced because the
distance between the magnets and the generator coil is shortened
owing to the absence of the guard ring.
[0048] Further, the method of manufacturing the magneto-generator
according to the instant embodiment of the invention includes the
resin filling step in which the resin molding die 21 having an
outer peripheral surface 21d to be positioned in opposition to the
inner peripheral surface of the flywheel 11 and the projections 21a
provided in the outer peripheral surface 21d for holding the
plurality of magnets 12 at predetermined positions, respectively,
is employed for filling the resin 14 in the spaces defined between
the resin molding die 21 and the flywheel 11 while holding the
magnets 12 at the predetermined positions, respectively, and the
die detaching step of detaching the resin molding die 21 from the
flywheel 11. Owing to the features described above, the guard ring
usually employed in this type conventional magneto-generator can be
omitted in the magneto-generator according to the present invention
and thus the manufacturing cost thereof can be reduced while the
performance of the magneto-generator can be enhanced because the
distance intervening between the magnets and the generator coil of
the magneto-generator is diminished owing to the omission of the
guard ring.
[0049] Many modifications and variations of the present invention
are possible in the light of the above techniques. It is therefore
to be understood that within the scope of the appended claims, the
invention may be practiced otherwise than as specifically
described.
* * * * *