1
DESCRIPTION
Title of Invention
MANUFACTURING METHOD FOR HELICAL CORE FOR ROTATING
5 ELECTRICAL MACHINE AND MANUFACTURING DEVICE FOR HELICAL CORE
FOR ROTATING ELECTRICAL MACHINE
Technical Field
10 The present invention relates to a manufacturing method of a helical core for a
rotating electrical machine. Particularly, the present invention is suitably used in the
manufacturing of a helically coiled core (helical core) that is used in a rotating electrical
machine.
15 Background Art
[0002]
A core of a stator (referred to as a stator core as necessary in descriptions below)
of a rotating electrical machine of a generator, an electric motor, or the like is formed by
laminating metal plates such as a magnetic steel sheet. The stator core includes a yoke
20 that extends in a circumferential direction of the stator core, and a plurality of teeth that
extend in a direction of a rotating shaft from an inner circumferential surface of the yoke.
In order to manufacture the stator core, a core piece, which has the sarhe shape as the
shape (shape on the plate surface) when viewed from thickness directions of the yoke and
the teeth, is punched from a metal plate, and the core pieces are laminated in the
25 thickness direction.
In the stator core manufactured as described above, at the time of the
manufacturing, since elastic deformation does not occur in a surface direction, the
magnetic characteristics are excellent. However, the outer circumferential shape of the
5 yoke is circular, and except in the portions where the teeth are formed, the more inward
portion than the inner circumference of the yoke is opened. Accordingly, if the stator
core is manufactured in this way, many unused portions occur in the metal plate that is
used for punching. Therefore, the yield of the metal plate is decreased, and the material
costs are increased.
10 [0004]
Thus, a helical core is used as the stator core in a rotating electrical machine
such as a generator for a vehicle. The helical core is formed by laminating belt-shaped
metal plates that are formed in shapes corresponding to the yoke and the teeth while
processing the metal plates into a helical shape by bending in the plate surface. For
15 example, the helical core is suitably used in a core for a rotating electrical machine in
which the diameter is 50 mm or more and 300 rnm or less. In this case, for example, as
the metal plate for the helical core, a belt-shaped metal plate, in which the plate thickness
is 0.15 rnm or more and 0.80 mm or less, is suitably used. However, if the bending
process in the plate surface is performed on the belt-shaped metal plate, the outer
20 circumferential side of the portion corresponding to the yoke of the belt-shaped metal
plate extends more largely than the inner circumferential side, and there is a concern that
the thickness of the outer circumferential side of the belt-shaped metal plate (yoke) may
be thinner than the thickness of the inner circumferential side.
[0005]
25 Thereby, in Patent Document 1, magnetic powder is filled in a gap that is
3
generated at the outer circumferential side of the core due to the fact that the outer
circumferential side of the portion corresponding to the yoke of the belt-shaped metal
plate more largely extends than the inner circumferential side. In this way, magnetic
characteristics and stiffness of the core can be recovered.
5 [0006]
Moreover, in Patent Document 2, a belt-shaped metal plate that is formed in a
shape corresponding to the yoke and the teeth is divided into a plurality of core pieces.
The circumference (the outer circumference of the portion corresponding to the yoke) of
each core piece is formed in an arc shape conforming to the shape of the yoke.
10 Moreover, the core pieces adjacent to each other are connected to each other by a
connection portion that is formed on the outer circumferential side of the side end of the
core piece, and each of core pieces, which is connected to each other by the connection
portion, linearly extends. If the plurality of core pieces are processed into a helical
shape by the bending processing in the plate surface, the regions of the inner
15 circumferential side rather than the connection portion in the side surfaces of the portions
corresponding to the yokes of the core pieces adjacent to each other are joined, and the
connection portion is deformed so as to be bent. Thereby, it is possible to prevent the
outer circumferential side corresponding to the yoke of the belt-shaped metal plate from
being thinner than the inner circumferential side.
20 Moreover, in Patent Document 3, a long belt-shaped silicon steel sheet is
punched, teeth and notches are formed at a time so as to leave bridge portions, and a unit
core element sheet is manufactured. Furthermore, after a laminated core is formed from
the unit iron core element sheets, an insulating layer is formed on the laminated core.
The material loss of the unit core element sheet is decreased by forming the notch on the
25 unit core element sheet, and strength of the laminated core according to the formation of
4
the notch is improved by forming the insulating layer on the laminated core.
Citation List
Patent Documents
[0007]
[Patent Document 11 Japanese Unexamined Patent Application, First
Publication No. 2005- 1850 14
[Patent Document 21 Japanese Unexamined Patent Application, First
~ublicationN o. 2009-15 3266
[Patent Document 31 Japanese Unexarnined Patent Application, First
Publication No. 2000- 11 6037
Summary of Invention
Technical Problem
However, in the technology disclosed in Patent Document 1, since the step for
filling the magnetic powder is needed, it is difficult to sufficiently decrease the cost of the
helical core for a rotating electrical machine.
Moreover, in the technology disclosed in Patent Document 2, the outer
circumference of each core piece is an arc shape, and the metal plate between core pieces
except for the portion corresponding to the connection portion is wasted. Accordingly,
the portion, which is not used as the stator core in the metal plate used for the punching,
is not sufficiently decreased. That is, in the technology disclosed in Patent Document 2,
even though the helical core is used as the stator core, yield of the metal plate is not
sufficiently decreased. Moreover, the belt-shaped metal plate disclosed in Patent
5
Document 2 has a complicated shape. As described above, also in the technology
disclosed in Patent Document 2, it is difficult to sufficiently decrease the cost of the
helical core for a rotating electrical machine.
Furthermore, in the technology disclosed in Patent Document 3, since the teeth
5 and notches are simultaneously punched, the strength of the unit core element plate is
decreased from the step in which the silicon steel sheet is punched, to the step in which
the laminated core is formed, and there is a concern that the unit core element sheet may
be deformed (bent) while the unit core element sheet passes. In this case, the shape of
the laminated core is deteriorated, and magnetic characteristics of the laminated core are
10 decreased.
The present invention is made in consideration of the above-described problems,
and an object thereof is to further decrease the cost of the helical core for a rotating
electrical machine compared with the related art.
15 Solution to Problem
[0009]
(1) According to an aspect of the present invention, there is provided a
manufacturing method of a helical core for a rotating electrical machine, including: a first
process of forming a yoke portion extending along one direction and a plurality of tooth
20 portions protruding toward a width direction of the yoke portion from a first side edge of
the width direction, with respect to a belt-shaped metal plate extending along the one
direction; a second process of forming a notch at a position between tooth portions of the
yoke portion after the first process; and a third process of processing the belt-shaped
metal plate into a helical shape by applying bending to the metal plate so that the
25 belt-shaped metal plate is curved toward the width direction sequentially fiom a portion
6
in which the notch is formed after the second process, and in the third process, a distance
between a position at which the application of the bending starts and the position at
which the notch is formed is limited to within a predetermined dimension.
(2) The manufacturing method of the helical core for a rotating electrical
machine described in (1) may further include a process of heating the belt-shaped metal
plate before the third process and after the second process.
(3) The manufacturing method of the helical core for a rotating electrical
machine described in (I) or (2) may further include a process of performing stress relief
annealing by heating the belt-shaped metal plate during or after the third process.
(4) In the manufacturing method of the helical core for a rotating electrical
machine described in (1) or (2), a depth dimension of the notch may be 112 times or more
of a width dimension of the yoke portion and be less than the width dimension of the
yoke portion.
(5) In the manufacturing method of the helical core for a rotating electrical
machine described in (1) or (2), a shape on a plate surface of the notch may be an
isosceles triangle or an equilateral triangle that includes a base on a first side edge in the
width direction of the yoke portion.
(6) In the manufacturing method of the helical core for a rotating electrical
machine described in (1) or (2), a shape on a plate surface of the notch may be a shape in
which a circle or an ellipse is added to a vertical angle of an isosceles triangle or an
equilateral triangle that includes a base on the first side edge in the width direction of the
yoke portion.
(7) In the manufacturing method of the helical core for a rotating electrical
machine described in (1) or (2), at least a portion of a second side edge in the width
direction of the yoke portion may be linear.
7
(8) In the manufacturing method of the helical core for a rotating electrical
machine described in (1) or (2), the predetermined dimension may be 10 mm or more and
1000 rnrn or less.
-
[OO lo]
(9) According to another aspect of the present invention, there is provided a
manufacturing apparatus of a helical core for a rotating electrical machine, including: a
first processing unit that forms a yoke portion extending along one direction and a
plurality of tooth portions protruding toward a width direction of the yoke portion from a
first side edge of the width direction, with respect to a belt-shaped metal plate extending
10 along the one direction; a second processing unit that forms a notch at a position between
tooth portions of the yoke portion; and a helical processing unit that processes the
belt-shaped metal plate into a helical shape by applying bending to the metal plate so that
the belt-shaped metal plate is curved toward the width direction sequentially from a
portion in which the notch is formed, wherein the distance between a position at which
15 the application of the bending starts in the helical processing unit and the position at
which the notch is formed in the second processing unit is within a predetermined
dimension.
(10) The manufacturing apparatus of the core for a rotating electrical machine
described in (9) may further include a heating unit that heats the belt-shaped metal plate
20 between the second processing unit and the helical processing unit.
(1 1) The manufacturing apparatus of the helical core for a rotating electrical
machine described in (9) or (1 0) may further include a stress relief heating unit that
performs stress relief annealing by heating the belt-shaped metal plate during or after the
belt-shaped metal plate is processed into a helical shape by the helical processing unit.
25 (12) The manufacturing apparatus of the helical core for a rotating electrical
8
machine described in (9) or (1 0) may further include a guide that supports the
belt-shaped metal plate from a lower side in at least a vertical direction between the first
processing unit and the helical processing unit.
(1 3) In the manufacturing apparatus of the helical core for a rotating electrical
5 machine described in (9) or (1 O), the predetermined dimension may be 10 mm or more
and 1000 mm or less.
Advantageous Effects of Invention
[OOll]
According to the present invention, the notch portion, in addition to the yoke
portion and the tooth portion, is formed on the belt-shaped steel sheet (belt-shaped metal
plate) that forms the helical core for a rotating electrical machine. The notch portion is
formed at the position between tooth portions of the yoke portion. By forming the
notch portion on the belt-shaped steel sheet, when the helical core for a rotating electrical
machine is formed, it is possible to prevent the thickness of the outer circumferential side
of the yoke of helical core for a rotating electrical machine from being thinner than the
thickness of the inner circumferential side. Moreover, when the belt-shaped steel sheet
is processed into a helical shape, stress can be more concentrated in the outer
circumferential side region of the yoke portion than in the notch portion. Accordingly,
unlike the related art, it is not necessary to perform a specific treatment after processing
the belt-shaped steel sheet into a helical shape, or to process the shape of the belt-shaped
steel sheet processed into a helical shape in a complicated shape. Furthermore, a helical
core for a rotating electrical machine having improved characteristics can be obtained,
and costs of the helical core for a rotating electrical machine can be decreased.
When the helical core for a rotating electrical machine is manufactured, the yoke
portion and the tooth portion, and the notch portion are separately formed on the
belt-shaped steel sheet, and the belt-shaped steel sheet is processed into a helical shape at
the position within the predetermined dimension after the notch portion is formed on the
belt-shaped steel sheet. Thus, bending of the belt-shaped steel sheet after the notch is
5 formed can be suppressed if possible, and the belt-shaped steel strip having various sheet
numbers (from one sheet to the plurality of sheets) can be flexibly prepared from one
belt-shaped steel sheet. Accordingly, magnetic characteristics, yield, and production
flexibility of the helical core for a rotating electrical machine are increased, and costs of
the helical core for a rotating electrical machine can be further decreased.
10
Brief Description of Drawings
[OO 1 21
FIG. 1 is a schematic view showing an example of a configuration of a rotating
electrical machine according to an embodiment of the present invention.
15 FIG. 2A is a schematic view showing an example of a belt-shaped steel sheet
before the sheet is processed into a helical shape in a manufacturing method of a helical
core for a rotating electrical machine according to an embodiment of the present
invention.
FIG. 2B is an enlarged view in the vicinity of a broken line portion shown in FIG.
20 2A.
FIG. 3 is a schematic view showing an example of a configuration of a
manufacturing apparatus of a helical core for a rotating electrical machine according to
an embodiment of the present invention.
FIG. 4A is a schematic view showing an example of an aspect (cutting position)
25 that forms a yoke portion and a tooth portion on a rectangular belt-shaped steel sheet in a
10
manufacturing method of a helical core for a rotating electrical machine according to an
embodiment of the present invention.
FIG. 4B is a schematic view showing an example of the aspect (cutting position)
that forms the yoke portion and the tooth portion on the rectangular belt-shaped steel
5 sheet in the manufacturing method of the helical core for a rotating electrical machine
according to the embodiment of the present invention.
FIG. 5 is a schematic view showing an example of a configuration of a rotating
electrical machine according to an embodiment of the present invention.
FIG. 6A is a schematic view showing an example of a belt-shaped steel sheet
10 before the sheet is processed into a helical shape in a manufacturing method of a helical
core for a rotating electrical machine according to an embodiment of the present
invention.
FIG. 6B is an enlarged view in the vicinity of a broken line portion shown in FIG.
6A.
15 FIG. 7A is a schematic view of an example (first disposition example) of a
manufacturing apparatus of a helical core for a rotating electrical machine that includes a
plurality of helical processing units when the example is viewed from the above in a
vertical direction.
FIG. 7B is a schematic view of an example (second disposition example) of a
20 manufacturing apparatus of a helical core for a rotating electrical machine that includes a
plurality of helical processing units when the example is viewed from a horizontal
direction.
FIG. 7C is a schematic view of an example (third disposition example) of a
manufacturing apparatus of a helical core for a rotating electrical machine that includes a
25 plurality of helical processing units when the example is viewed from a horizontal
11
direction.
FIG. 8 is a schematic view showing an example of a.configuration of a
manufacturing apparatus of a helical core for a rotating electrical machine according to a
modification of the embodiment.
5
Description of Embodiments
[00 1 31
Hereinafter, an embodiment of the present invention will be described referring
to the drawings.
10 First, an example of a helical core will be described, which is manufactured by a
manufacturing method of a helical core for a rotating electrical machine according to the
present embodiment.
FIG. 1 is a schematic view showing an example of a configuration of a rotating
electrical machine which is an application example of the helical core for a rotating
15 electrical machine. Specifically, FIG 1 is a cross-sectional view when the rotating
electrical machine is cut from a direction perpendicular to the rotating shaft.
In FIG. 1, the rotating electrical machine 10 includes a stator (stationary portion)
*
11, a rotor (rotator) 12, a case 13, and a rotating shaft 14. Moreover, in FIG. 1, for
convenience of the illustration, members such as a coil are omitted.
20 [0014]
The stator 11 has a stator core that includes a yoke that extends in a
circumferential direction of the rotating electrical machine, and teeth that extend from an
inner circumferential side end (end surface) of the yoke in the direction of the rotating
shaft 14. Moreover, a coil (not shown) is inserted so as to be coiled around the teeth in
25 a slot which is a region between teeth adjacent to each other in the circumferential
12
direction of the rotating electrical machine. The stator core is a helical core.
Moreover, FIG. 1 exemplifies a case where the number of teeth is 12. However, the
number of the teeth is not limited to the example shown in FIG. 1.
[00 1 51
As shown in FIG. 1, in the present embodiment, cut lines 15a to 151 (1 5) are
formed from the inner circumferential surface of the stator 11 toward the outer
circumferential surface in a middle position in the circumferential direction of each slot.
The surfaces of cut lines 15a to 151 opposite to each other are joined to each other, and
gaps almost do not exist in the cut line 15a to 151. In the present embodiment, stress is
more concentrated at the outer circumferential side region of the stator 11 than at the cut
lines 15a to 151. Thereby, the stress generated in the cut lines 15a to 151 is preferably
small if possible within a range which is smaller than the stress generated in the outer
circumferential side region of the stator 11, and is most preferably 0.
[00 1 61
Moreover, when the stator 11 is formed by a method described below, the (radial
directional) length of the cut line 15 (1 5a to 151) is preferably long if possible within a
range in which the shape of the stator 11 does not get damaged. The outer
circumferential side region of the stator 11 is smaller than the cut line 15 (that is, the cut
line 15 is long if possible), if possible, and thus, the region is prevented from being
included in a magnetic path.
Specifically, the length of the cut line 15 is at least 112 times or more of the
length in the radial direction of the yoke. The length of the cut line 15 is preferably 314
times or more of the length in the radial direction of the yoke, and is more preferably 415
times or more of the length in the radial direction of the yoke. However, the length of
the cut line 15 is less than the length in the radial direction of the yoke.
[00 1 71
The rotor 12 is disposed in a position at which the outer circumferential surface
of the rotor is opposite with a predetermined interval to the tip surfaces (that is, the inner
circumferential surface of the stator 11) of the teeth of the stator 11. Furthermore, the
5 shaft center (rotating shaft 14) of the rotor 12 approximately coincides with the shaft
center (the center of gravity) of the stator 11. Moreover, in the present embodiment, in
order to explain the stator 11 as an example of the characterized portion of the helical
core, in FIG. 1, the configuration of the rotor 12 is shown to be simplified.
[00 1 81
10 An assembly processing such as shrinkage fitting is performed to the case 13,
and thus, the case 13 closely contacts the stator 11 from the circumference (outer
circumference) of the stator 11 and the stator 11 may be fixed, and the stator 11 may be
fixed to the case 13 by welding or bolting. For example, the case 13 is configured of
soft iron or stainless steel.
15 [00 1 91
FIGS. 2A and 2B are schematic views showing an example of a belt-shaped
steel sheet before the sheet is processed into a helical shape. Specifically, FIG. 2A is a
view when the belt-shaped steel sheet is viewed from a direction perpendicular to the
plate surface. Moreover, FIG. 2B is an enlarged view of a region surrounded by a
20 broken line in FIG. 2A. Moreover, the steel sheet (belt-shaped steel sheet) is an
example of a metal plate (belt-shaped metal plate), and specifically, the metal plate
includes a magnetic steel sheet, a cold rolled steel sheet, and a hot rolled steel sheet.
[0020]
As shown in FIG. 2A, a yoke portion 22 corresponding to the yoke of the stator
25 11, tooth portions 23a to 23e (23) corresponding to the teeth of stator 11, and notch
14
portions 24a to 24b (24) are formed on a belt-shaped steel sheet 21 that extends along
one direction. Moreover, in FIG. 2A, only five tooth portions 23 are shown. However,
the tooth portions 23 having the same number as that of the teeth of the stator 11 are
formed on the belt-shaped steel sheet 21. Moreover, in FIG. 2A, only four notch
portions 24 are shown. However, the notch portions 24 having the same number as that
of the cut lines 15a to 151 are formed on the belt-shaped steel sheet 2 1.
Furthermore, a width direction of the yoke portion 22 and a longitudinal
direction (extension direction) of the tooth portion 23 coincide with each other, and a
longitudinal direction of the yoke portion 23 and a width direction (a direction
10 perpendicular to the longitudinal direction of the tooth portion 23) of the tooth portion 23
coincide with each other.
[0021]
1 As shown in FIG. 2A, the tooth portions 23 are formed at equal intervals along
/i
I the longitudinal direction (extension direction) of the belt-shaped steel sheet 21 so that
15 the tooth portions protrude from a first side edge (end) in the width direction of the yoke
portion 22 toward the width direction.
The notch portion 24 (notch) is formed at position between tooth portions 23 of
the yoke portion 22. In the present embodiment, since a helical core is used as the stator
core, the notch portion 24 is formed in a position that is positioned at an end (one end in
20 the width direction of the yoke portion 22 and an end of a side in which the tooth portion
23 is formed on the yoke portion 22) of the inner side of the yoke portion 22 and is
positioned at the middle (the middle of tooth portions 23 adjacent to each other) in the
longitudinal direction of an end of the yoke portion 22 corresponding to a bottom of each
slot. Moreover, the notch portions 24 are formed one by one over all region (the end of
25 the yoke portion 22 corresponding to bottoms of the slots) corresponding to the slots.
Furthermore, an end (other end in the width direction of the yoke portion 22 and
an end of a side of in which the tooth portion 23 is not formed on the yoke portion 22) of
the outer side of the yoke portion 22 of the belt-shaped steel sheet 21 is linear. Since the
end of the outer side of the yoke portion 22 of the belt-shaped steel sheet 2 1 is linear,
5 when the belt-shaped steel sheet 2 1 is processed into a helical shape, nonuniform
deformation and unexpected distortion are prevented, and shape accuracy of the
belt-shaped steel sheet 21 can be increased. Thereby, it is preferable that at least a
portion of the end of the outer side of the yoke portion 22 of the belt-shaped steel sheet
21 be linear. Moreover, for example, an attachment groove to the case 13 may be
10 provided on the end of the outer side of the yoke portion 22 of the belt-shaped steel sheet
21.
[0022]
The shape of the notch portion 24 on the plate surface is an isosceles triangle or
an equilateral triangle having a base on the end (one end in the width direction) of the
15 inner side (tooth portion 23 side) of the yoke portion 22. The width W (width
dimension) of the notch portion 24 in the end of the inner side of the yoke portion 22 is a
value corresponding to (proportional to) a difference between the length of the outer
circumference and the length of the inner circumference of the stator 11. Moreover, it is
preferable that the length (depth dimension) D of the notch portion 24 be long if possible
20 within a range in which the shape of the stator 11 does not get damaged when the stator
11 is formed according to a method as described below. As described above, in this
case, a region 25 (refer to FIG. 2B), in which stress generated by processing the
belt-shaped steel sheet 2 1 into a helical shape is concentrated, can be decreased if
possible. Specifically, since the length D of the notch portion 24 corresponds to the
25 length of the cut line 15, the length D (depth dimension) of the notch portion 24 is at
least 112 times or more of the length in the width direction of the yoke portion 22 (width
dimension and the length between the end of the inner side (tooth portion 23 side) of the
yoke portion 22 and the end of the outer side). The length D of the notch portion 24 is
preferably 314 times or more of the length in the width direction of the yoke portion 22,
5 and is more preferably 415 times or more of the length in the width direction of the yoke
portion 22. However, the length D of the notch portion 24 is less than the length in the
width direction of the yoke portion 22.
[0023]
The belt-shape steel sheet 21 is configured as described above, and thus, the
10 - difference between the length the outer circumference and the length of the inner
circumference of the stator 11 can be corrected by the notch portion 24, and oblique lines
26 and 27 (refer to FIG. 2B) of the notch portion 24 opposite to each other can be aligned
with each other when the belt-shaped steel sheet 21 is processed into a helical shape
according to a method described below.
15 [0024]
Furthermore, if the oblique lines of the notch portion opposite to each other can
be aligned with each other when the belt-shaped steel sheet is processed into a helical
shape, a shape of a notch portion may be different from the above-mentioned shape of
the notch portion 24. Hereinafter, an example of a notch portion having the shape
20 different from that of the notch portion 24 will be described. Moreover, it is assumed
that configurations other than the notch portion are the same as the configurations of the
above descriptions, the same reference numerals as the reference numerals attached in
FIG. 1 are attached to the same portions as the configurations of the above descriptions,
or the like, and the detailed descriptions thereof are omitted here.
2 5 [0025]
17
FIG. 5 is a schematic view showing an example of a configuration of a rotating
electrical machine which is an application example of the helical core for the rotating
electrical machine. FIG. 5 corresponds to FIG. 1.
In FIG. 5, a rotating electrical machine 50 includes a stator 5 1, the rotor 12, the
5 case 13, and the rotating shaft 14.
As shown in FIG 5, in the present embodiment, cut lines 52a to 521 (52) are
formed from the inner circumferential surface of the stator 5 1 toward the outer
circumference in the middle position in the circumferential direction of each slot, and
circular column shaped or elliptical column shaped holes 53a to 531 (53) are formed on
10 the tips of the cut lines 52a to 521 (side close to the end of the outer circumferential side
of the stator 5 1). Surfaces of cut lines 52a to 521 opposite to each other are joined to
each other, the stress generated in the opposite surfaces (cut lines 52a to 521) is preferably
small, and if possible within a range which is smaller than the stress generated in the
outer circumferential side region of the stator 5 1, and is most preferably 0. Moreover,
15 when the stator 5 1 is formed by a method described below, the total value of the (radial
directional) lengths of the cut line 52 and the hole 53 is preferably long if possible within
a range in which the shape of the stator 5 1 does not get damaged.
[0026]
FIGS. 6A and 6B are schematic views showing an example of a belt-shaped
20 steel sheet before the sheet is processed into a helical shape. FIGS. 6A and 6B
correspond to FIGS. 2A and 2B respectively.
As shown in FIG. 6A, the yoke portion 22, tooth portions 23a to 23e (23), and
notch portions 62a to 62d (62) are formed on a belt-shaped steel sheet 61.
Since a helical core is used as the stator core, the notch portion 62 (notch) is
25 formed in a position that is positioned at an end (one end in the width direction of the
18
yoke portion 22 and an end of a side in which the tooth portion 23 is formed on the yoke
portion 22) of the inner side of the yoke portion 22 and is positioned at the middle (the
middle of tooth portions 23 adjacent to each other) in the longitudinal direction of an end
of the yoke portion 22 corresponding to a bottom of each slot. Moreover, the notch
5 portions 62 are formed one by one over all region (the end of the yoke portion 22
corresponding to bottoms of the slots) corresponding to the slots.
[0027]
The shape of the notch portion 62 on the plate surface is a shape in which a
circle or an ellipse is added to a vertical angle of an isosceles triangle or an equilateral
10 triangle having a base on the end (one end in the width direction) of the inner side (tooth
portion 23 side) of the yoke portion 22. That is, in the notch portion 62, the circle or the
ellipse is disposed so as to include the vertical angle of the isosceles triangle or the
equilateral triangle. The width W of the notch portion 62 in the end of the inner side of
the yoke portion 22 is a value corresponding to (proportional to) a difference between the
15 length of the outer circumference and the length of the inner circumference of the stator
5 1. Moreover, it is preferable that the length (depth dimension) D of the notch portion
62 be long if possible within a range in which the shape of the stator 5 1 does not get
damaged when the stator 5 1 is formed according to a method as described below.
Also when the above-described notch portion 62 is formed on the yoke portion
20 22, effects similar to those when the notch portion 24 is formed on the yoke portion 22
can be obtained.
[0028]
The shapes of the plate surfaces of the belt-shaped steel sheet 21 shown in FIG.
2A and the belt-shaped steel sheet 61 shown in FIG. 6A described above are obtained by
25 a processing method (cutting processing) such as slitter cutting processing by a roll blade,
punching, or processing by laser. Hereinafter, for simplification of explanation, a case
where the helical core for a rotating electrical machine is manufactured from the
belt-shaped steel sheet 2 1 shown in FIG 2A will be described.
First, a manufacturing method of the helical core for a rotating electrical
5 machine and a basic configuration of a manufacturing apparatus thereof will be
described.
FIG. 3 is a schematic view showing an example of a configuration of the
manufacturing apparatus of the helical core for a rotating electrical machine (stator 11).
Moreover, a void arrow shown in FIG 3 indicates a direction in which the belt-shaped
10 steel sheet moves.
In FIG. 3, the manufacturing apparatus of the helical core for a rotating electrical
machine includes a shape processing unit 3 1 (first processing unit), a notch processing
unit 32 (second processing unit), and a helical processing unit 33.
[0029]
15 The shape processing unit 3 1 performs processing such as slitter cutting
processing by a roll blade with respect to the rectangular belt-shaped steel sheet 34, and
forms the yoke portion 22 and the tooth portion 23 shown in FIG 2A. In this step, the
notch portion 24 is not formed.
[0030]
20 The notch processing unit 32 performs processing such as punching with respect
to the belt-shaped steel sheet 35 on which the yoke portion 22 and the tooth portion 23
are formed, and sequentially forms the notch portion 24 shown in FIG. 2A by a
predetermined number (one or two or more). The notch processing unit 32 (a position
at which the notch portion 24 is formed) is disposed at a position which does not interfere
25 with the helical processing unit 33 and a position within a predetermined distance
20
(predetermined dimension) from the position at which the belt-shaped steel sheet 36 is
processed into a helical shape. If the distance from the position at which the notch
portion 24 is formed on the belt-shaped steel sheet 35 to the position at which the
belt-shaped steel sheet 36 is processed into a helical shape is long, there is a concern that
.. 5 the belt-shaped steel sheet 36 may be bent due to existence of the notch portion 24 before
the sheet is processed into a helical shape. Particularly, the longer the length D of the
notch portion 24, the higher the possibility that the belt-shaped steel sheet 36 may be bent.
In this way, if the belt-shaped steel sheet 36 is bent, the belt-shaped steel sheet 36 is
I deformed, the oblique lines of the notch portion opposite to each other cannot I be aligned
10 to each other when the steel sheet is processed into a helical shape, and thus, a gap occurs
in the cut line 15 of the helical core.
In this case, magnetic characteristics of the belt-shaped steel sheet 36 itself may
I be decreased or magnetic characteristics of the helical core may be decreased.
Moreover, since the belt-shaped steel sheet 36 is processed into a helical shape in a state
where the steel sheet is bent in the lamination direction, a gap occurs in the lamination
direction of the belt-shaped steel sheet 36, and thus, the shape of the helical core is
deteriorated. Furthermore, when the shape of the helical core is forcibly corrected,
since large processing distortion is introduced to the helical core, magnetic characteristics
of the helical core are largely decreased. Accordingly, in order to suppress the decrease
of the magnetic characteristics due to the bending, it is preferable that a distance (the
predetermined dimension) x between a coiling position (a position at which the being
processing starts) of the helical processing and the end surface of the side close to the
coiling position in the notch processing unit 32 which forms the notch portion 24 be 1000
mm or less. In order to further improve the magnetic characteristics of the helical core,
the distance x is more preferably 500 mm or less, and is most preferably 300 mm or less.
Moreover, the distance x may be appropriately set according to the strength and the
thickness of the belt-shaped steel sheet, and the depth dimension of the notch portion.
For example, when the length D of the notch portion 24 is 314 times or more of the length
in the width direction of the yoke portion 22, the distance x may be set to 500 mm or less.
5 Moreover, the distance x may be set to 10 mm or more so that the notch processing unit
32 and the helical processing unit 33 (or the belt-shaped steel sheet 36 which is subjected
to the helical processing) do not interfere with each other.
[003 11
The helical processing unit 33 laminates the belt-shaped steel sheet 36 while
10 processing the steel sheet into a helical shape by applying bending to the steel sheet so as
to sequentially bend the belt-shaped steel sheet 36 toward the plate width direction (the
I
direction perpendicular to the plate-passing direction and the plate thickness direction)
from the portion in which the notch portion 24 is formed by the notch processing unit 32.
Specifically, the helical processing unit 33 may process the belt-shaped steel sheet 36
15 into a helical shape by a nonuniform pressure roll or may forcibly process the belt-shaped
steel sheet 36 into a helical shape by making the steel sheet be along a guide so that the
length in the longitudinal direction (circumferential direction) of the yoke portion 22 is
longer than the length in the width direction (circumferential direction) of the tooth
portion 23. In this way, the yoke portion 22 is disposed on the outer circumferential
20 side of the stator 11, and the tooth portion 23 is disposed on the inner circumferential side
of the stator 11. Moreover, the belt-shaped steel sheet 36 that is processed and
laminated by the helical processing unit moves downwardly in the vertical direction
while being coiled around a core bar (not shown) of the helical processing unit.
Thereby, the belt-shaped steel sheet 34 can be passed without changing the passing
s 25 height of the belt-shaped steel sheet 34.
22
For example, the belt-shaped steel sheet 36, which is processed into a helical
shape, is connected at a predetermined portion (for example, lamination direction) by a
connecting method such as caulking, bonding, or welding. The connection of the
belt-shaped steel sheet 36 processed into a helical shape ends in this way, and the stator
5 11 is formed by performing a predetermined treatment if necessary.
[0032]
Furthermore, as described above, in the present embodiment, the notch portion
24 is formed on the belt-shaped steel sheet 35 at the position immediately before the
belt-shaped steel sheet 36 is processed into a helical shape after the yoke portion 22 and
10 the tooth portion 23 are formed on the belt-shaped steel sheet 34. For example, if the
notch portion 24 along with the yoke portion 22 and the tooth portion 23 are formed on
the belt-shaped steel sheet at a time, since stiffness of the belt-shaped steel sheet is
decreased, the belt-shaped steel sheet is deformed before the belt-shaped steel sheet
reaches the helical processing unit 33, and the magnetic characteristics and the shape of
15 the helical core are deteriorated. Moreover, since the notch portion 24 along with the
yoke portion 22 and the tooth portion 23 are simultaneously formed, it is difficult to
reuse a processing unit (for example, a die or CAD data) due to the change of dimension
such as the length D of the notch portion 24, and thus, there is a concern that the costs
may be increased. Moreover, even when the position at which the yoke portion 22, the
20 tooth portion 23, and the notch portion 24 are formed at a time is immediately before the
position in which the belt-shaped steel sheet is processed into a helical shape, since it is
difficult to manufacture a plurality of belt-shaped steel sheets 41 and 42 from one
rectangular belt-shaped steel sheet 34a as shown in FIG. 4A, production flexibility of the
helical core is decreased.
2 5 [0033]
Furthermore, in the manufacturing method and the manufacturing apparatus of
the helical core for a rotating electrical machine of the present embodiment, the
i following configurations may be provided as modifications of the present embodiment in
>
addition to the above-described basic configuration.
I
i i 5 The manufacturing apparatus of the helical core for a rotating electrical machine
i
may include a guide that suppresses deformation of the belt-shaped steel sheets 35 and 36.
For example, the guide (for example, a guide 37 shown in FIG. 8) is disposed between
1 the shape processing unit 3 1 and the helical processing unit 33 so as to support the
belt-shaped steel sheets 35 and 36 at least from the lower side in the vertical direction.
Furthermore, the guide may support the belt-shaped steel sheets 35 and 36 from the upper
side and the lower side in the vertical direction.
[0034]
Moreover, when a hard steel sheet (particularly, 3% Si-based magnetic steel
sheet) such as a magnetic steel sheet is processed into a helical shape, as shown in FIG 8,
a heating unit 38 that heats the belt-shaped steel sheet 36 is disposed between the notch
processing unit 32 and the helical processing unit 33, and the belt-shaped steel sheet 36
may be heated after the notch processing. In this way, the belt-shaped steel sheet 36 is
heated at the position immediately before the belt-shaped steel sheet 36 is processed into
a helical shape, and thus, the processability of the belt-shaped steel sheet 36 is improved
temporarily, and the belt-shaped steel sheet 36 can be effectively processed into a helical
shape certainly. The heating temperature of the heating unit 38 may be determined
according to the steel sheet. For example, the heating temperature is approximately
300°C in 3% Si-based magnetic steel sheet.
[003 51
Moreover, according to above-described process, distortion (for example,
24
punching distortion or bending distortion) occurs in the helical core. Since the
distortion decreases the magnetic characteristics of the helical core, it is preferable that
the distortion be removed by performing the heating. For example, as shown in FIG. 8,
stress relief annealing (SRA) may be performed to the belt-shaped steel sheet 36 in an
on-line using a stress relief heating unit 39 such as an induction heating furnace while
coiling the belt-shaped steel sheet 36 around the core bar (not shown) of the helical
processing unit 33 immediately after the belt-shaped steel sheet 36 is processed by the
helical processing unit 33. Moreover, for example, stress relief annealing may be
performed to a core, in which the helical processing ends, at a separate line using an
external heating unit such as an induction heating furnace or a box type furnace. In this
case, the distortion, which is generated due to connection methods such as caulking,
bonding, or welding, can be also removed. It is preferable that the above-described
stress relief annealing be appropriately performed according to the characteristics
required in the helical core and the kind of the belt-shaped steel sheet 36. For example,
the annealing temperature of the stress relief annealing is approximately 750°C.
[0036]
Furthermore, the notch processing unit may be installed so as to move or rotate
in the width direction of the passing belt-shaped steel sheet. In this case, the depth
dimension of the notch portion and the position of the notch portion can be flexibly
adjusted without changing the processing unit.
[0037]
FIGS. 4A and 4B are schematic views showing an example of an aspect (cutting
position) that forms the yoke portion 22 and a tooth portion 23 on the rectangular
belt-shaped steel sheet 34.
[003 81
In FIG. 4A, the rectangular belt-shaped steel sheet 34a is processed so that the
tip side of the tooth portion 23 of one belt-shaped steel sheet 41 (42) is disposed in a
region corresponding to the slot of the other belt-shaped steel sheet 42 (41) (that is, the
tooth portion 23 of one belt-shaped steel sheet 41 (42) and the tooth portion 23 of the
5 other belt-shaped steel sheet 42 (41) are alternately disposed to each other). In this case,
unnecessary portions of the belt-shaped steel sheet 34 can be decreased if possible, and a
decrease in yield of the belt-shaped steel sheet 34a can be prevented if possible. In this
case, for example, the shape of the one belt-shaped steel sheet 41 (42) and the shape of
the other belt-shaped steel sheet 42 (41) may be different from each other. For example,
10 dimensions such as the length in the longitudinal direction of the tooth portion 23 or the
width of the yoke portion 22 may be appropriately changed.
[0039]
Moreover, it is not necessary to form the plurality of belt-shaped steel sheets 41
and 42 from the one rectangular belt-shaped steel sheet 34a as shown in FIG. 4A. That
15 is, as shown in FIG. 4B, one belt-shaped steel sheet 43 may be formed fkom the single
rectangular belt-shaped steel sheet 34b. In this case, since the end (one end) of the outer
side of the yoke portion 22 is linear, even though the belt-shaped steel sheet 43 is formed
as shown in FIG. 4B, unnecessary portions of the rectangular belt-shaped steel sheet 34b
in the region of the outer side (the one end side) than the yoke portion 22 can be reduced
20 as compared to the related art.
[0040]
Moreover, in the present embodiment, when the plurality of the belt-shaped steel
sheets 41 and 42 are formed from the one rectangular belt-shaped steel sheet 34a as
shown in FIG. 4A, for example, as shown in FIGS. 7A to 7C, the manufacturing
25 apparatus of the helical core for a rotating electrical machine may include a plurality of
helical processing units 33 (33a and 33b) and a plurality of notch processing units 32
(32a and 32b). FIG. 7A is a schematic view of an example (first disposition example) of
the manufacturing apparatus of the helical core for a rotating electrical machine that
includes the plurality of helical processing units when the example is viewed from the
5 above in a vertical direction. In FIG 7A, two helical processing units 33a and 33b are
disposed to be lined up in the horizontal direction, and each notch processing unit 32a
(32b) is disposed immediately before a corresponding helical processing unit 33a (33b).
Moreover, the belt-shaped steel sheets 41 and 42 that are formed by the shape processing
unit 3 1 are separated respectively, and are transported in directions different from each
10 other. The belt-shaped steel sheet 41 (42) is processed by the notch processing unit 32a
(32b) and the helical processing unit 33a (33b), and the helical core is manufactured.
FIG. 7B is a schematic view of an example (second disposition example) of the
manufacturing apparatus of the helical core for a rotating electrical machine that includes
the plurality of helical processing units when the example is viewed from a horizontal
15 direction. In FIG. 7B, two helical processing units 33a and 33b are disposed to be lined
up in the vertical direction, and each notch processing unit 32a (32b) is disposed
immediately before each helical processing unit 33a (33b). In this case, for example,
since the centers of the helical cores can be aligned, the same power can be used for the
helical processing unit 33a and 33b. Moreover, as shown in FIG. 7C, one helical
20 processing unit in FIG. 7B may be deviated in the horizontal direction. If the
disposition method satisfies a condition in which the belt-shaped steel sheet is not
deformed before the belt-shaped steel sheet reaches the helical processing unit 33 (for
example, the distance from the notch processing unit 32a (32b) to the helical processing
unit 33a (33b) is within a predetermined dimension), the disposition method of two
25 helical processing unit is not particularly limited.
[004 11
Furthermore, in the above-described disposition example, since each of the
belt-shaped steel sheets 41 and 42 is separated and is transported in directions different
from each other, if the transport distance fiom the shape processing unit to the helical
5 processing unit is short, each of the belt-shaped steel sheets 41 and 42 is deformed, and
the magnetic characteristics and the shape of the helical core may be deteriorated.
Thereby, in order to sufficiently decrease an angle between the transport directions when
each of the belt-shaped steel sheets 41 and 42 is separated, it is preferable that the
transport distance from the shape processing unit 3 1 to the helical processing unit 33 be a
10 predetermined value or more. As described above, when the yoke portion 22, the tooth
portion 23, and the notch portion 24 are formed on the belt-shaped steel sheet at a time,
since stiffness of the belt-shaped steel sheet is small, the belt-shaped steel sheet is
deformed before the belt-shaped steel sheet reaches the helical processing unit, and the
magnetic characteristics and the shape of the helical core are deteriorated. In this case,
15 if the plurality of belt-shaped steel sheets 41 and 42 are formed from the one rectangular
belt-shaped steel sheet 34a, the transport distance fiom the shape processing unit 3 1 to
the helical processing unit 33 is increased. Accordingly, in the present disposition
example, as shown FIGS. 7A to 7C, the plurality of notch processing units 32 (32a and
32b) are needed in addition to the shape processing unit 3 1, each notch processing unit
20 32 is disposed in the position within a predetermined distance (predetermined dimension)
from each of the helical processing unit 33 (33a and 33b). In this case, the one
belt-shaped steel sheet can be formed from the one rectangular belt-shaped steel sheet
34a by changing the line, and production quantity can be flexibly adjusted. Moreover,
by appropriately adding the helical processing unit 33 and the notch processing unit 32
25 corresponding to the helical processing unit, the plurality belt-shaped steel sheets having
2 8
different shapes can be formed from the one rectangular belt-shaped steel sheet 34a. In
this case, for example, the helical cores having different diameters can be manufactured
by adding different kinds of the helical processing units 33 (33b). In this way, the
manufacturing method and the manufacturing apparatus of the helical core for a rotating
5 electrical machine of the present embodiment can correspond to the helical cores
(belt-shaped steel sheets) having various shapes.
[0042]
As described above, in the present embodiment, after the yoke portion 22 and
the tooth portion 23 are formed by the shape processing unit 3 1, the notch portion 24 is
10 formed by the notch processing unit 32 at the position immediately before the
belt-shaped steel sheet is processed into a helical shape, and the belt-shaped steel sheet is
processed into a helical shape while curvature is sequentially applied to the belt-shaped
steel sheet from the portion on which the notch portion 24 is formed, at the position
within the predetermined distance (predetermined dimension) from the position at which
15 the notch portion 24 is formed. Accordingly, bending of the belt-shaped steel sheet due
to existence of the notch portion 24 can be prevented as much as possible before the
belt-shaped steel sheet is processed into a helical shape.
[0043]
Furthermore, in the helical core that is manufactured by the manufacturing
20 method of the helical core for a rotating electrical machine of the present embodiment,
the belt-shaped steel sheet 2 1 when the helical core for a rotating electrical machine is
formed includes the rectangular yoke portion 22, a tooth portion 23 that protrudes at
equal intervals from one end in the width direction of the yoke portion 22, and the notch
portion 24. The notch portion 24 is formed at the position which is the middle between
25 tooth portions 23 adjacent to each other at the end (the one end) of the side in which the
tooth portion 23 of the yoke portion 22 is formed. Moreover, when the belt-shaped steel
sheet 2 1 is processed into a helical shape, the oblique lines 26 and 27 of the notch portion
!
I 24 opposite to each other are aligned to each other. In the stator 11 (the helical core for
a rotating electrical machine), it is possible to prevent the thickness of the outer
* 5 circumferential side of the yoke from being thinner than the thickness of the inner
circumferential side. Furthermore, when the belt-shaped steel sheet 21 is processed into
a helical shape, stress can be more concentrated at the outer circumferential side region
25 of the yoke portion 22 (yoke) than at the notch portion 24 (cut line 15).
[0044]
Accordingly, in the above-described helical core, unlike the related art, it is not
necessary to perform a specific treatment after processing the belt-shaped steel sheet into
a helical shape, or to process the shape of the belt-shaped steel sheet processed into a
helical shape in a complicated shape. Moreover, in the manufacturing method of the
helical core for a rotating electrical machine of the present embodiment, the helical core
15 for a rotating electrical machine having improved characteristics (for example, the helical
core for a rotating electrical machine excellent at accuracy of the dimensions such as
circularity or the thickness or the magnetic characteristics) can be obtained, and costs of
the helical core for a rotating electrical machine can be decreased. Furthermore, since
the belt-shaped steel sheet 41 shown in FIG. 4A can be formed, the unnecessary portions
20 of the rectangular belt-shaped steel sheet 34a can be further decreased, and the costs of
the helical core for a rotating electrical machine can be further decreased.
[0045]
Moreover, in the manufacturing method and the manufacturing apparatus of the
helical core for a rotating electrical machine described in the present embodiment, not
25 only the stator of the rotating electrical machine but also the helical core used in the rotor
can be manufactured.
[0046]
Furthermore, the above-described embodiment of the present invention is only
an embodied example for carrying out the present invention, and accordingly, the
5 technical scope of the present invention should not be interpreted restrictively. That is,
the present invention may be carried out in various forms without departing fiom the
main characteristics thereof.
[Example 11
[0047]
The belt-shaped steel sheet having the shape shown in FIG. 2A was prepared
using a product hoop of SPCC-SD (0.02%C) defined by JIS G3141 and 0.50 mrn
thickness and a magnetic steel sheet product hoop of 0.002%C, O.l%Si, and 0.35 mm
thickness, and a helical core stator of 30 mm thickness was manufactured. In the helical
core stator, the outer diameter of the stator was 120 mmcp, and the inner diameter (the
15 inner diameter that includes the bottom of the slot) of the tooth root portion was 90 mmcp.
Moreover, the depth dimensions of the cut line 15 shown in FIG. 1 were variously
changed with respect to the length (width dimension) in the width direction of the yoke
(hereinafter, the depth dimension of the cut line 15 with respect to the length in the width
direction of the yoke is referred to as a ratio of the notch portion). Furthermore, an
20 integral round-punched core was also prepared as Comparative Example. Evaluation
results of the ratio of the notch portion and the shape of the steel sheet of the region 25
(stress concentrated portion) shown in FIG. 2B are shown in Table 1 (SPCC-SD) and
Table 2 (magnetic steel sheet) with respect to helical core stators that are manufactured
from each product hoop. In the stress concentrated portions of Tables 1 and 2, a case
25 where the notch portion was not formed was set to "0", a case where the notch portion
3 1
having the ratio of the notch portion of 0.9 was formed was set to "lo", and the
evaluations were performed by 10 levels according to ratios (shapes) that were improved
by the formation of the notch portion. It is shown that the larger the number is, the
better the shape of the stress concentrated portion is. From Tables 1 and 2, it is
5 understood that the shape of the steel sheet of the region 25 (stress concentrated portion)
is good when the notch portion is formed on the yoke portion. Particularly, when the
ratios of the notch portion were changed to 0.5,0.75, and 0.80 respectively, the shape of
the stress concentrated portion was improved largely. Furthermore, Tables 1 and 2 also
show a relationship between the ratio of the notch portion and the yield ("excellent" or
10 "bad") of the stator. Moreover, compared to a case where the round-punched core was
made from each product hoop, the yield of the stator was good in the case where the
helical core was prepared. Furthermore, since the notch processing unit was disposed
immediately before the helical processing unit, even though the notch portion was
formed on the yoke portion and the ratio of the notch portion was increased, the yield of
15 the stator was good.
LO0481
[Table 11
No.
1 0
2
3
4
5
6
7
Shape of the stress
concentrated portion
0
2
4
7
9
10
10
Ratio of the notch portion
0.2
0.4
0.5
0.75
0.8
0.9
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
8 Round-punched stator core Bad
[Table 21
[Example 21
5 [0050]
The belt-shaped steel sheet having the shape shown in FIG. 2A was prepared
using a product hoop of 35A210 (3.1%Si) defined by JIS C2552 and 0.35 mm thickness,
and a helical core stator of 30 mrn thickness was manufactured. In the helical core
stator, the outer diameter of the stator was 200 mrncp, and the inner diameter of the tooth
10 root portion was 180 mmcp. Moreover, the depth dimensions of the cut line 15 shown in
FIG. 1 were variously changed with respect to the length in the width direction of the
yoke (hereinafter, the depth dimension of the cut line 15 with respect to the length in the
width direction of the yoke is referred to as a ratio of the notch portion). Furthermore,
an integral round-punched core was also prepared as Comparative Example. Evaluation
15 results of the ratio of the notch portion and the shape of the steel sheet of the region 25
(stress concentrated portion) shown in FIG. 2B are shown in Table 3. The evaluation
method was performed using the same criteria as that of Example 1. From Table 3, it is
understood that the shape of the steel sheet of the region 25 (stress concentrated portion)
is good when the notch portion is formed on the yoke portion. Particularly, when the
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Bad
No.
1 0
2
3
4
5
6
7
8
Ratio of the notch portion
0.2
0.4
0.5
0.75
0.8
0.9
Shape of the stress
concentrated portion
0
2
4
7
9
10
10
Round-punched stator core
33
ratios of the notch portion were changed to 0.5,0.75, and 0.80 respectively, the shape of
the stress concentrated portion was improved largely. Moreover, compared to a case
where the round-punched core was made fkom the product hoop, the yield of the stator
was good in the case where the helical core was prepared. Furthermore, since the notch
5 processing unit was disposed immediately before the helical processing unit, even though
the notch portion was formed on the yoke portion and the ratio of the notch portion was
increased, the yield of the stator was good.
[005 11
[Table 31
10
[Example 31
[0052]
The belt-shaped steel sheet having the shape shown in FIG. 6A was prepared
using a product hoop of 50A470 (2.O%Si) defined by JIS C2552 and 0.50 rnm thickness
15 and a product hoop of 50A800 (0.8%Si) defined by JIS C2552 and 0.50 mm thickness,
and a helical core stator of 30 mm thickness was manufactured. In the helical core
No.
1 0
2
3
4
5
6
7
stator, the outer diameter of the stator was 120 rnmcp, and the inner diameter of the tooth
root portion was 90 rnmcp. Moreover, the depth dimensions of the cut line 52 shown in
FIG. 5 were variously changed with respect to the length in the width direction of the
Shape of the stress
concentrated
0
2
4
7
9
10
10
Ratio of the notch portion
0.2
0.4
0.5
0.75
0.8
0.9
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
8 Round-punched stator core Bad
yoke (hereinafter, the depth dimension of the cut line 15 with respect to the length in the
width direction of the yoke is referred to as a ratio of the notch portion). Furthermore,
an integral round-punched core was also prepared as Comparative Example. Evaluation
results of the ratio of the notch portion and the shape of the steel sheet of the stress
5 concentrated portion near the circular portion of the notch portion 62 shown in FIG. 6B
are shown in Table 4 (50A470) and Table 5 (50A800) with respect to helical core stators
that are manufactured from each product hoop. The evaluation method was performed
using the same criteria as that of Example 1. From Tables 4 and 5, it is understood that
the shape of the steel sheet of the stress concentrated portion near the circular portion of
10 the notch portion 62 is good when the notch portion 62 is formed on the yoke portion.
Particularly, when the ratios of the notch portion were changed to 0.5,0.75, and 0.80
respectively, the shape of the stress concentrated portion was improved largely.
Moreover, compared to a case where the round-punched core was made from a product
hoop, the yield of the stator was good in the case where the helical core was prepared.
15 Furthermore, since the notch processing unit was disposed immediately before the helical
processing unit, even though the notch portion was formed on the yoke portion and the
ratio of the notch portion was increased, the yield of the stator was good.
[0053]
[Table 41
No.
1 0
2
3
4
5
6
7
8
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Bad
Ratio of the notch portion
0.2
0.4
0.5
0.75
0.8
0.9
Shape of the stress
concentrated portion
0
2
4
7
9
10
10
Round-punched stator core
[0054]
[Table 51
[Example 41
[0055]
The yoke portion and the tooth portion were formed on the belt-shaped steel
sheet by a die (punch) of a first stage using the same product hoops as Example 1
(SPCC-SD and magnetic steel sheet), and two belt-shaped steel sheets as shown in FIG.
4A were prepared. Moreover, after the notch portion shown in FIG. 2A was formed
10 with respect to each belt-shaped steel sheet by two dies of a second stage, two helical
core stators of 30 mm thickness were manufactured by two nonuniform pressure rolls.
In the helical core stator, the outer diameter of the stator was 120 mmcp, and the inner
No.
1 0
2
3
4
5
6
7
diameter (the inner diameter that includes the bottom of the slot) of the tooth root portion
Shape of the stress
concentrated portion
0
2
4
7
9
10
10
Ratio of the notch portion
0.2
0.4
0.5
0.75
0.8
0.9
was 90 mrncp. Furthermore, the ratio of the notch portion was set to 0.5. Moreover,
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
15 the distance from the die forming the notch portion to the nonuniform pressure roll
performing the helical processing was variously changed, and the helical core was
manufactured. Furthermore, in the manufacturing apparatus of the helical core, the
distances from the dies of the first stage to the nonuniform pressure rolls were set to be
the same distance in two lines. Moreover, one line of the manufacturing apparatus of
8 Round-punched stator core Bad
the same helical core as the above was selected, and the belt-shaped steel sheet, in which
the shape of one sheet was processed as shown in FIG. 4B, was also prepared.
Furthermore, as Comparative Example, a helical core was prepared with a condition
(condition in which a die was not disposed as the notch processing unit) in which the
5 yoke portion, the tooth portion, and the notch portion were simultaneously formed using
a die. In this case, in order to prepare two belt-shaped steel sheets that were
shape-processed fiom one belt-shaped steel sheet and smoothly introduce the steel sheets
into two nonuniform pressure rolls, the distance from the die to the nonuniform pressure
rolls needed to be at least 2500 mm. Thereby, in this case, the distance fiom the die to
10 the nonuniform pressure rolls was set to 2500 mm.
[0056]
Evaluation results of the distance from the die forming the notch portion to the
nonuniform pressure rolls, the shape of the helical core, and magnetic characteristics are
shown in Table 6 (SPCC-SD) and Table 7 (magnetic steel sheet) with respect to helical
15 core stators that are manufactured from each product hoop. Moreover, in the evaluation
method of the shape of the helical core and the magnetic characteristics, a case where the
yoke portion, the tooth portion, and the notch portion were simultaneously formed using
the die (a case where the die for the notch processing unit was not present) was set to "O",
a case where the distance fiom the die (notch processing unit) forming the notch portion
20 to the nonuniform pressure roll (helical processing unit) was 20 mm was set to "lo", the
evaluations were performed by 10 levels according to ratios (shape and magnetic
1 characteristics) that were improved by decreasing the distance between the die forming
the notch portion and the nonuniform pressure rolls. It is shown that the larger the
number is, the better the shape and magnetic characteristics of the helical core are.
25 From Tables 6 and 7, compared to the case where the die, which simultaneously formed
3 7
the yoke portion, the tooth portion, and the notch portion, was used, the shape and the
magnetic characteristics of the helical core were improved largely in the case where the
die forming the yoke portion and the tooth portion and the die forming the notch portion
were used. Particularly, when the distance between the die forming the notch portion
5 and the nonuiform pressure roll was changed to 1000 mm, 500 mm, and 300 mm, the
shape and the magnetic characteristics of the helical core were largely improved.
Furthermore, Tables 6 and 7 also show a relationship between the distance from the die
forming the notch portion to the nonuniform pressure roll and the yield ("excellent",
"good", or "bad) of the stator. The yield of the stator was good at all conditions, and the
10 yield was further improved by preparing two belt-shaped steel sheet from one
belt-shaped steel sheet.
[0057]
[Table 61
No.
1
2
3
4
5
6
7
8
9
10
11
Applicati
on of the
die
forming
the notch
portion
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Distance from
the die
forming the
notch portion
to the
nonuniform
pressure rolls
20
100
300
400
500
750
1000
2000
2500
1000
2500
Number
of helical
core
produced
2
2
2
2
2
2
2
2
2
1
2
Shape
the
helical
core
10
10
10
9
7
5
4
1
0
3
0
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Good
Excellent
Magnetic
characteristics
10
10
10
9
7
5
4
1
0
3
0
[0058]
[Table 71
Industrial Applicability
[0059]
According to the present invention, magnetic characteristics, yield, and
production flexibility of a helical core for a rotating electrical machine are increased, and
costs of the helical core for a rotating electrical machine can be hrther decreased than the
related art.
Reference Signs List
[0060]
10,50 rotating electrical machine
1 1, 5 1 stator
12 rotor
Yield
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Good
Excellent
Shape
ofthe
helical
core
10
10
10
9
7
5
4
1
0
3
0
Magnetic
characteristics
10
10
10
9
. 7
5
4
1
0
3
0
No.
1
2
3
4
5
6
7
8
9
10
11
Applicati
on of the
die
forming
the notch
portion
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Number
of
core
produced
2
2
2
2
2
2
2
2
2
1
2
Distance from
the die
forming the
notch portion
to- -t he
nonuniform
pressure rolls
20
100
300
400
500
750
1000
2000
2500
1000
2500
13 case
14 rotating shaft
15 cut line
2 1,61 belt-shaped steel sheet
5 22 yoke portion
23 tooth portions
24,62 notch portion (notch)
3 1 shape processing unit (first processing unit)
32 notch processing unit (second processing unit)
33 helical processing unit
37 guide
38 heating unit
39 stress relief heating unit
52 cut line
53 hole

40
CLAIMS
1. A manufacturing method of a helical core for a rotating electrical machine,
the method comprising:
5 a first process of forming a yoke portion extending along one direction and a
plurality of tooth portions protruding toward a width direction of the yoke portion from a
first side edge of the width direction, with respect to a belt-shaped metal plate extending
along the one direction;
a second process of forming a notch at a position between the tooth portions of
10 the yoke portion, after the first process; and
a third process of processing the belt-shaped metal plate into a helical shape by
applying bending to the metal plate so that the belt-shaped metal plate is curved toward
the width direction sequentially from a portion in which the notch is formed, after the
second process,
15 wherein, in the third process, a distance between a position at which application
of the bending starts and a position at which the notch is formed is limited to within a
predetermined dimension.
2. The manufacturing method of the helical core for a rotating electrical
20 machine according to claim 1, the method further comprising,
a process of heating the belt-shaped metal plate before the third process and after
the second process.
3. The manufacturing method of the helical core for a rotating electrical
25 machine according to claim 1 or 2, the method further comprising,
4 1
a process of performing stress relief annealing by heating the belt-shaped metal
plate during or after the third process.
4. The manufacturing method of the helical core for a rotating electrical
5 machine according to claim 1 or 2,
wherein a depth dimension of the notch is 112 times or more of a width
dimension of the yoke portion and is less than the width dimension of the yoke portion.
5. The manufacturing method of the helical core for a rotating electrical
10 machine according to claim 1 or 2,
wherein a shape on a plate surface of the notch is an isosceles triangle or an
equilateral triangle that includes a base on the first side edge in the width direction of the
yoke portion.
15 6. The manufacturing method of the helical core for a rotating electrical
machine according to claim 1 or 2,
wherein a shape on a plate surface of the notch is a shape in which a circle or an
ellipse is added to a vertical angle of an isosceles triangle or an equilateral triangle that
includes a base on the first side edge in the width direction of the yoke portion.
20
7. The manufacturing method of the helical core for a rotating electrical
machine according to claim 1 or 2,
wherein at least a portion of a second edge in the width direction of the yoke
portion is linear.
25
42
8. The manufacturing method of the helical core for a rotating electrical
machine according to claim 1 or 2,
wherein the predetermined dimension is 10 mrn or more and 1000 rnrn or less.
5 9. A manufacturing apparatus of a helical core for a rotating electrical machine,
the apparatus comprising:
a first processing unit that forms a yoke portion extending along one direction
and a plurality of tooth portions protruding toward a width direction of the yoke portion
from a first side edge of the width direction, with respect to a belt-shaped metal plate
10 extending along the one direction;
a second processing unit that forms a notch at a position between tooth portions
of the yoke portion; and
a helical processing unit that processes the belt-shaped metal plate into a helical
shape by applying bending to the metal plate so that the belt-shaped metal plate is curved
15 toward the width direction sequentially from a portion in which the notch is formed,
wherein a distance between a position at which application of the bending starts
in the helical processing unit and the position at which the notch is formed in the second
processing unit is within a predetermined dimension.
20 10. The manufacturing apparatus of the helical core for a rotating electrical
machine according to claim 9, the apparatus further comprising,
a heating unit that heats the belt-shaped metal plate between the second
processing unit and the helical processing unit.
25 11. The manufacturing apparatus of the helical core for a rotating electrical
43
machine according to claim 9 or 10, the apparatus further comprising,
a stress relief heating unit that performs stress relief annealing by heating the
belt-shaped metal plate during or after the belt-shaped metal plate is processed into a
C
helical shape by the helical processing unit.
12. The manufacturing apparatus of the helical core for a rotating electrical
machine according to claim 9 or 10, the apparatus further comprising,
a guide that supports the belt-shaped metal plate from a lower side in at least a
vertical direction between the fxst processing unit and the helical processing unit.
10
13. The manufacturing apparatus of the helical core for a rotating electrical
' machine according to claim 9 or 10,
wherein the predetermined dimension is 10 mm or more and 1000 mrn or less.
Dated this 18.06.2013
[NEHA SRIVASTAVA]
OF REMFRY & SAGAR
ATTORNEY FOR THE APPLICANT[S]