FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
STATOR, MOTOR, FAN, AIR CONDITIONER, AND MANUFACTURING METHOD OF
STATOR;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI
2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND
THE MANNER IN WHICH IT IS TO BE PERFORMED.

2
DESCRIPTION
TITLE OF THE INVENTION
STATOR, MOTOR, FAN, AIR CONDITIONER, AND MANUFACTURING METHOD
OF STATOR
5 TECHNICAL FIELD
[0001]
The present invention relates to a stator, a motor, a fan, an
air conditioner, and a manufacturing method of the stator.
BACKGROUND ART
10 [0002]
A stator includes a stator core, an insulator, and a coil
wound on the stator core via the insulator. The insulator is
composed of a resin and formed integrally with the stator core (see,
for example, Patent Reference 1).
15 PRIOR ART REFERENCE
PATENT REFERENCE
[0003]
[PATENT REFERENCE 1]
Japanese Patent Application Publication No. S50-158805 (FIGS.
20 3 to 7)
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0004]
In order to wind the coil densely on the stator core, it is
25 desirable to reduce the thickness of the insulator. Thus, there is
a demand for further reducing the thickness of the insulator.
[0005]
The present invention is intended to solve the above-described
problem, and an object of the present invention is to reduce the
30 thickness of an insulator.
MEANS OF SOLVING THE PROBLEM
[0006]
A stator of the present invention includes a stator core
having a yoke extending in a circumferential direction about an axis
3
and a tooth extending from the yoke toward the axis, an insulator
having a winding portion surrounding the tooth, and a coil wound
around the winding portion of the insulator. The winding portion of
the insulator has a first end portion located at one side of the
5 tooth in a direction of the axis, a second end portion located at
the other side of the tooth in the direction of the axis, and a side
portion located at one side of the tooth in the circumferential
direction. The first end portion has a maximum thickness T1 in the
direction of the axis, and the second end portion has a maximum
10 thickness T2 in the direction of the axis. The side portion has a
maximum thickness T3 in the circumferential direction. The maximum
thicknesses T1, T2 and T3 satisfy T3 < T1 < T2. The insulator has a
gate mark on the same side as the first end portion in the direction
of the axis.
15 EFFECTS OF THE INVENTION
[0007]
According to the present invention, the first portion of the
winding portion of the insulator, i.e., a portion which is close to
a gate of a molding mold and where fluidity of resin is high, has a
20 small thickness. Thus, the thickness of the insulator can be
effectively reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008]
FIG. 1 is a partial sectional view illustrating a motor of a
25 first embodiment.
FIG. 2 is a sectional view illustrating the motor of the first
embodiment.
FIG. 3 is a perspective view illustrating a stator of the
first embodiment.
30 FIG. 4 is a top view illustrating the stator of the first
embodiment.
FIG. 5 is a perspective view illustrating an insulator of the
first embodiment.
FIG. 6 is a sectional view illustrating a tooth, the insulator,
4
and a coil of the first embodiment.
FIG. 7 is a sectional view illustrating a molding mold for
forming the insulator of the first embodiment.
FIG. 8 is a sectional view of the molding mold taken along a
5 line VIII-VIII illustrated in FIG. 7.
FIG. 9 is a sectional view illustrating a molding mold for
molding a mold resin portion of the first embodiment.
FIG. 10 is a flowchart illustrating a manufacturing process of
the motor of the first embodiment.
10 FIG. 11 is a graph illustrating a relationship between a
thickness of the insulator and a motor efficiency.
FIG. 12 is a graph illustrating a relationship between a resin
temperature during molding and each of a melt viscosity and a
flowability.
15 FIG. 13 is a graph illustrating a relationship between a
molding pressure and a flow length.
FIG. 14 is a diagram illustrating a relationship among maximum
thicknesses T1, T2, and T3 of a first end portion, a second end
portion, and a side portion of the insulator of the first embodiment
20 (A) in comparison with those of a comparison example (B).
FIG. 15 is a sectional view illustrating a tooth, an insulator,
and a coil of a second embodiment.
FIG. 16(A) is a sectional view illustrating a tooth, an
insulator, and a coil of a third embodiment, and FIGS. 16(B) and (C)
25 are enlarged diagrams illustrating corner portions of the insulator
of the third embodiment.
FIG. 17(A) is a diagram illustrating a configuration example
of an air conditioner to which the motor of each embodiment is
applicable, and FIG. 17(B) is a sectional view illustrating an
30 outdoor unit.
MODE FOR CARRYING OUT THE INVENTION
[0009]
Embodiments of the present invention will be described in
detail below with reference to the figures. The present invention
5
is not limited to these embodiments.
[0010]
FIRST EMBODIMENT
(Configuration of Motor 100)
5 FIG. 1 is a longitudinal-sectional view illustrating a motor
100 according to a first embodiment of the present invention. The
motor 100 is a brushless DC motor which is used in, for example, a
fan of an air conditioner and driven by an inverter. The motor 100
is an Interior Permanent Magnet (IPM) motor in which magnets 55 are
10 embedded in a rotor 5.
[0011]
The motor 100 includes the rotor 5 having a shaft 7, and a
mold stator 4 surrounding the rotor 5. The mold stator 4 includes a
stator 1 having an annular shape and surrounding the rotor 5, and a
15 mold resin portion 40 covering the stator 1. The shaft 7 is a
rotation shaft of the rotor 5.
[0012]
In the description below, a direction of a center axis C1 of
the shaft 7 is referred to as an "axial direction". A
20 circumferential direction about the center axis C1 of the shaft 7 is
referred to as a "circumferential direction" and indicated by an
arrow S in FIG. 2 and other figures. A radial direction about the
center axis C1 of the shaft 7 is referred to as a "radial direction".
A sectional view in a plane parallel to the axial direction is
25 referred to as a "longitudinal-sectional view".
[0013]
The shaft 7 protrudes from the mold stator 4 to the left side
in FIG. 1. An impeller 505 (FIG. 17(A)) of a fan, for example, is
attached to an attachment portion 7a formed at a protruding portion
30 of the shaft 7. Thus, the protruding side (the left side in FIG. 1)
of the shaft 7 is referred to as a "load side", while the opposite
side (the right side in FIG. 1) of the shaft 7 is referred to as a
"counter-load side".
[0014]
6
(Configuration of Rotor 5)
FIG. 2 is a sectional view illustrating the motor 100 except
for the mold resin portion 40 (FIG. 1). The rotor 5 includes the
shaft 7 serving as the rotation shaft, a rotor core 50 provided at a
5 distance from the shaft 7 outward in the radial direction, a
plurality of magnets 55 embedded in the rotor core 50, and a resin
portion 6 provided between the shaft 7 and the rotor core 50.
[0015]
The rotor core 50 is a member having an annular shape about
10 the center axis C1. An inner circumference of the rotor core 50
faces the shaft 7 at a distance from the shaft 7. The rotor core 50
is formed of a plurality of stacking elements that are stacked in
the axial direction and fixed together by crimping, welding, or
bonding. The stacking elements are, for example, electromagnetic
15 steel sheets. The thickness of each stacking element is, for
example, 0.2 mm to 0.5 mm.
[0016]
The rotor core 50 has a plurality of magnet insertion holes 51
in the circumferential direction. The magnet insertion holes 51 are
20 arranged at equal intervals in the circumferential direction and at
equal distances from the center axis C1. The number of magnet
insertion holes 51 is 10 in this example. The magnet insertion
holes 51 are formed along an outer circumference of the rotor core
50 and extend from one end to the other end of the rotor core 50 in
25 the axial direction.
[0017]
One magnet 55 is inserted in each magnet insertion hole 51.
The magnet 55 is also referred to as a main magnet. The magnet 55
is in the form of a flat plate. The magnet 55 has a thickness in
30 the radial direction and is magnetized in the thickness direction.
[0018]
Each magnet 55 constitutes a magnetic pole. In this example,
the number of magnets 55 is 10, and thus the number of magnetic
poles of the rotor 5 is 10. The number of magnetic poles of the
7
rotor 5 is not limited to 10 and only needs to be two or more. A
center of the magnet insertion hole 51 in the circumferential
direction is a pole center, and a portion between adjacent magnet
insertion holes 51 is an inter-pole portion.
5 [0019]
The magnet 55 is a rare earth magnet. More specifically, the
magnet 55 is a neodymium magnet containing Nd (neodymium), Fe (iron)
and B (boron), or a samarium cobalt magnet containing Sm (samarium)
and Co (cobalt). Instead of the rare earth magnet, a ferrite magnet
10 that contains Fe may be used.
[0020]
Although one magnet 55 is disposed in each magnet insertion
hole 51 in this example, two or more magnets 55 may be disposed in
each magnet insertion hole 51.
15 [0021]
A flux barrier 52 which is an aperture is formed at each end
of the magnet insertion hole 51 in the circumferential direction.
The flux barrier 52 prevents shortcircuit of a magnetic flux between
adjacent magnets 55.
20 [0022]
Core holes 54 are formed on the inner side in the radial
direction of the magnet insertion holes 51 of the rotor core 50. In
this example, each core hole 54 is formed at a position
corresponding to the pole center. The core holes 54 are formed to
25 reduce the amount of core material of the rotor core 50. However,
the core holes 54 are not necessarily formed.
[0023]
In a section perpendicular to the axial direction, the rotor
core 50 has an outer circumference of a so-called flower shape such
30 that the rotor core 50 has a maximum diameter at the pole center of
each magnetic pole and a minimum diameter at each inter-pole portion.
The outer circumference of the rotor core 50 is not limited to such
a flower shape and may be a circular shape.
[0024]
8
The resin portion 6 is provided between the shaft 7 and the
rotor core 50. The resin portion 6 holds the shaft 7 and the rotor
core 50 in such a manner that the shaft 7 and the rotor core 50 are
apart from each other. The resin portion 6 is formed of a
5 nonmagnetic body. The resin portion 6 is formed of a thermoplastic
resin such as polybutylene terephthalate (PBT). The above-described
core holes 54 of the rotor core 50 are filled with the same resin as
the resin portion 6 to constitute filling portions 61.
[0025]
10 As illustrated in FIG. 1, the resin portion 6 also covers both
ends of the rotor core 50 in the axial direction. The resin portion
6 holds a sensor magnet 56 on the counter-load side of the rotor
core 50. The sensor magnet 56 is a magnet having an annular shape
about the axis C1 and has the same number of magnetic poles as that
15 of the magnets 55. The sensor magnet 56 is magnetized in the axial
direction. The magnetic flux of the sensor magnet 56 is detected by
a magnetic sensor 44 described later.
[0026]
Although the resin portion 6 is provided between the shaft 7
20 and the rotor core 50 in this example, it is also possible to fit
the shaft 7 into a center hole of the rotor core 50 without
providing the resin portion 6.
[0027]
Although the Inner Permanent Magnet (IPM) rotor in which the
25 magnets 55 are embedded in the rotor core 50 has been described, it
is also possible to employ a Surface Permanent Magnet (SPM) motor in
which the magnets 55 are attached to the surface of the shaft 7.
[0028]
(Configuration of Mold Stator 4)
30 As described above, the mold stator 4 includes the stator 1
and the mold resin portion 40. The mold resin portion 40 is formed
of a thermosetting resin such as a bulk molding compound (BMC). The
mold resin portion 40 has an opening 41 on the load side and a
bearing support portion 42 on the counter-load side. The rotor 5 is
9
inserted through the opening 41 into a hollow portion inside the
mold stator 4.
[0029]
A metal bracket 73 is attached to the opening 41 of the mold
5 resin portion 40. One bearing 71 that supports the shaft 7 is held
by the bracket 73. A cap 74 is attached to the outside of the
bracket 73. The bearing support portion 42 of the mold resin
portion 40 has an inner circumferential surface of a cylindrical
shape. The other bearing 72 supporting the shaft 7 is held by the
10 inner circumferential surface of the bearing support portion 42.
[0030]
A circuit board 43 is held by the mold resin portion 40 on the
counter-load side of the stator 1. The circuit board 43 is a
printed board on which a driving circuit such as a power transistor
15 for driving the motor 100 is mounted. Lead wires 45 are wired on
the circuit board 43. The lead wires 45 on the circuit board 43 are
drawn to the outside of the motor 100 via a lead wire outlet
component 46 attached to an outer circumferential portion of the
mold resin portion 40.
20 [0031]
The magnetic sensor 44 is mounted on a surface of the circuit
board 43 on the stator 1 side so that the magnetic sensor 44 faces
the sensor magnet 56 in the axial direction. The magnetic sensor 44
is formed of, for example, a Hall effect element, a Magneto
25 Resistive (MR) element, a Giant Magneto Resistive (GMR) element, or
a magnetic impedance element.
[0032]
The magnetic sensor 44 outputs a binary signal when the
magnetic sensor 44 faces the N-poles and the S-poles of the sensor
30 magnet 56 in turn. A position of the magnet 55, i.e., a rotational
position of the rotor 5, is detected based on the output signal of
the magnetic sensor 44.
[0033]
It is also possible to perform sensorless control by
10
estimating the rotational position of the rotor 5 based on a current
or voltage applied to coils 3 without providing the sensor magnet 56
and the magnetic sensor 44.
[0034]
5 The bracket 73 is press-fitted into an annular portion
provided at an outer periphery of the opening 41 of the mold resin
portion 40. The bracket 73 is formed of a metal having conductivity,
for example, a galvanized steel sheet. The cap 74 is attached to
the outside of the bracket 73 and prevents water or the like from
10 entering the bearing 71.
[0035]
In this example, the stator 1 is covered with the mold resin
portion 40. However, instead of providing the mold resin portion 40,
the outer circumference of the stator 1 may be fitted inside a
15 cylindrical shell formed of metal.
[0036]
As illustrated in FIG. 2, the stator 1 surrounds the rotor 5
from an outer side in the radial direction. The stator 1 includes a
stator core 10, insulators 2 provided on the stator core 10, and the
20 coils 3 wound on the stator core 10 via the insulators 2.
[0037]
The stator core 10 is formed of a plurality of stacking
elements that are stacked in the axial direction and fixed together
by crimping, welding, or bonding. The stacking elements are, for
25 example, electromagnetic steel sheets. The thickness of each
stacking steel sheet is, for example, 0.2 mm to 0.5 mm. The stator
core 10 has a yoke 11 that extends annularly in the circumferential
direction about the center axis C1 and a plurality of teeth 12
extending inward in the radial direction (toward the center axis C1)
30 from the yoke 11.
[0038]
A slot 13 is formed between the adjacent teeth 12. An end
surface (an end surface 12e illustrated in FIG. 3) on the inner side
in the radial direction of the tooth 12 faces an outer
11
circumferential surface of the rotor 5. The number of teeth 12 is
nine in this example. The number of teeth 12 is not limited to nine
and only needs to be two or more.
[0039]
5 Crimping portions 18 and 19 for fixing the above-described
stacking elements together are respectively formed on the yoke 11
and teeth 12. The positions of the crimping portions are not
limited to these positions. The stacking elements may be fixed not
only by crimping, but also by welding or bonding.
10 [0040]
The stator core 10 has a configuration such that the stator
core 10 is divided into a plurality of connecting cores 10A each
including one tooth 12. The connecting cores 10A are divided at
split surfaces 14 formed in the yoke 11. The split surfaces 14
15 extend outward in the radial direction from the inner
circumferential surface of the yoke 11. A thin portion that is
plastically deformable is formed between an outer end of the split
surface 14 and the outer circumferential surface of the yoke 11. By
plastic deformation of the thin portions, the stator core 10 can be
20 expanded in a band shape.
[0041]
The stator core 10 is not limited to a combination of the
connecting cores 10A and may be formed of annular stacking steel
sheets which are stacked in the axial direction.
25 [0042]
The insulator 2 formed of a resin is provided so as to
surround the tooth 12 of the stator core 10. The coil 3 is composed
of a magnet wire and wound around the tooth 12 via the insulator 2.
The coil 3 is housed in the slot 13 between adjacent teeth 12.
30 [0043]
(Configuration of Insulator 2)
FIGS. 3 and 4 are a perspective view and a top view
illustrating the stator core 10 and the insulators 2. The insulator
2 is formed of an insulating resin. For example, the insulator 2 is
12
formed of a thermoplastic resin such as polybutylene terephthalate
(PBT), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), or
polyethylene terephthalate (PET). The insulator 2 is formed by
molding the resin integrally with the stator core 10 or by
5 assembling a molded body of the resin to the stator core 10.
[0044]
Since the stator core 10 is formed of the connecting cores 10A
(FIG. 2) as described above, the insulators 2 can be molded
integrally with the teeth 12, and then the coils 3 can be wound
10 around the teeth 12 via the insulators 2 in a state where the stator
core 10 is expanded in a band shape.
[0045]
FIG. 5 is a perspective view illustrating one tooth 12 of the
stator core 10 and the insulator 2 surrounding the tooth 12. The
15 insulator 2 has a winding portion 21 that surrounds the tooth 12
from both sides in the circumferential direction and from both sides
in the axial direction, an inner wall portion 22 adjacent to and on
the inner side in the radial direction of the winding portion 21,
and an outer wall portion 23 adjacent to and on the outer side in
20 the radial direction of the winding portion 21.
[0046]
The inner wall portion 22 is provided at a tip end on the
inner side of the tooth 12 in the radial direction. The outer wall
portion 23 is provided to span the yoke 11 and a root portion on the
25 outer side of the tooth 12 in the radial direction. The inner wall
portion 22 and the outer wall portion 23 face each other in the
radial direction. The coil 3 (FIG. 3) is wound around the winding
portion 21. The inner wall portion 22 and the outer wall portion 23
guide the coil 3 from both sides in the radial direction.
30 [0047]
The winding portion 21 has a first end portion 21a located at
one side of the tooth 12 in the axial direction, a second end
portion 21b located at the other side of the tooth 12 in the axial
direction, and a pair of side portions 21c located at both sides of
13
the tooth 12 in the circumferential direction.
[0048]
The inner wall portion 22 has a first wall portion 22a located
at one side of the tooth 12 in the axial direction, a second wall
5 portion 22b located at the other side of the tooth 12 in the axial
direction, and a pair of side wall portions 22c located at both
sides of the tooth 12 in the circumferential direction.
[0049]
The outer wall portion 23 has a first wall portion 23a located
10 at one side of the tooth 12 in the axial direction, a second wall
portion 23b located at the other side of the tooth 12 in the axial
direction, and a pair of side portions 23c located at both sides of
the tooth 12 in the circumferential direction.
[0050]
15 The first end portion 21a of the winding portion 21, the first
wall portion 22a of the inner wall portion 22, and the first wall
portion 23a of the outer wall portion 23 are located on the same
side as each other in the axial direction. The second end portion
21b of the winding portion 21, the second wall portion 2b of the
20 inner wall portion 22, and the second wall portion 23b of the outer
wall portion 23 are located on the same side as each other in the
axial direction.
[0051]
As illustrated in FIG. 5, a gate mark G is formed on the first
25 wall portion 22a of the inner wall portion 22. The gate mark G is a
portion corresponding to a gate 313 of a molding mold used for
molding of the insulator 2. The gate mark G is formed, for example,
as a concave portion or a convex portion on a surface on the inner
side in the radial direction of the first wall portion 22a of the
30 inner wall portion 22.
[0052]
FIG. 6 is a sectional view illustrating the tooth 12, the
winding portion 21 of the insulator 2, and the coil 3. FIG. 6 is a
sectional view in a plane perpendicular to an extending direction of
14
the tooth 12.
[0053]
The tooth 12 has a rectangular sectional shape in a section
perpendicular to the extending direction of the tooth 12. End
5 surfaces 12a and 12b of the tooth 12 in the axial direction are
covered with the first end portion 21a and the second end portion
21b of the winding portion 21. End surfaces 12c of the tooth 12 in
the circumferential direction are covered with the side portions 21c
of the winding portion 21.
10 [0054]
The first end portion 21a of the winding portion 21 has a
maximum thickness T1 in the axial direction. That is, the first end
portion 21a of the winding portion 21 has an outer circumferential
surface 211 on a side opposite to the end surface 12a of the tooth
15 12. A maximum distance from the end surface 12a of the tooth 12 to
the outer circumferential surface 211 defines the maximum thickness
T1.
[0055]
In FIG. 6, the outer circumferential surface 211 of the first
20 end portion 21a is shown as a curved surface projecting on a side
opposite to the tooth 12 in the axial direction, but the outer
circumferential surface 211 may be a flat surface.
[0056]
The second end portion 21b of the winding portion 21 has a
25 maximum thickness T2 in the axial direction. That is, the second
end portion 21b of the winding portion 21 has an outer
circumferential surface 212 on a side opposite to the end surface
12b of the tooth 12. A maximum distance from the end surface 12b of
the tooth 12 to the outer circumferential surface 212 defines the
30 maximum thickness T2.
[0057]
In FIG. 6, the outer circumferential surface 212 of the second
end portion 21b is shown as a curved surface projecting on a side
opposite to the tooth 12 in the axial direction, but the outer
15
circumferential surface 212 may be a flat surface.
[0058]
The side portion 21c of the winding portion 21 has a maximum
thickness T3 in the circumferential direction. The thickness of the
5 side portion 21c is constant in the axial direction in FIG. 6, but
is not necessarily constant.
[0059]
The maximum thicknesses T1, T2 and T3 of the portions 21a, 21b,
and 21c of the winding portion 21 satisfy T3 < T1 < T2.
10 [0060]
In other words, in the winding portion 21, the maximum
thickness T1 of the first end portion 21a on the same side as the
gate mark G in the axial direction is smaller than the maximum
thickness T2 of the second end portion 21b on the side opposite to
15 the gate mark G. The maximum thickness T3 of the side portion 21c
is smaller than each of the maximum thicknesses T1 and T2.
[0061]
In a molding step of the insulator 2, the resin exhibits
higher fluidity at a position closer to the gate which is an inlet
20 for the resin. Therefore, the first end portion 21a of the winding
portion 21 is more suitable to be thinned than the second end
portion 21b of the winding portion 21. This will be described later.
[0062]
(Manufacturing Method of Motor 100)
25 Next, a manufacturing process of the motor 100 will be
described. FIG. 7 is a diagram illustrating a molding mold 30 for
molding the insulators 2. The molding mold 30 has an upper mold 31
which is a movable mold, and a lower mold 32 which is a stationary
mold. A cavity 33 is formed between the upper and lower molds 31
30 and 32.
[0063]
The stator core 10 is placed in the cavity 33 in such a manner
that the stator core 10 is expanded in a band shape. In the cavity
33, a molding space 34 is formed for each tooth 12 of the stator
16
core 10. Cores 38 are disposed on both sides of each tooth 12 in
the cavity 33 for securing spaces for disposing the coils 3 (FIG. 6).
[0064]
The stator core 10 is placed in the cavity 33 in such a manner
5 that the stator core 10 is expanded in a band shape in this example,
but the stator core 10 may be annularly placed in the cavity 33.
[0065]
The upper mold 31 has a sprue 311, runners 312 and gates 313
for injecting resin into the cavity 33. The sprue 311 is a flow
10 path into which molten resin flows from a cylinder 315 as an
injection device. The gate 313 are inlets provided each for one
tooth 12 in the cavity 33. The runners 312 are flow paths that
branch off from the sprue 311 and lead to the gates 313.
[0066]
15 FIG. 8 is a sectional view taken along line VIII-VIII
illustrated in FIG. 7 as seen in a direction indicated by arrows.
The cavity 33 has a winding portion area 35 for forming the winding
portion 21, an inner wall portion area 36 for forming the inner wall
portion 22, and an outer wall portion area 37 for forming the outer
20 wall portion 23, for each of the insulators 2.
[0067]
The gate 313 described above is open in a portion 361 for
forming the first wall portion 22a (FIG. 5) of the inner wall
portion 22, of the inner wall portion area 36 of the cavity 33. The
25 resin injected into the cavity 33 from the gate 313 flows from the
side for forming the first end portion 21a and the first wall
portions 22a and 23a (FIG. 5) toward the side for forming the second
end portion 21b and the second wall portions 22b and 23b (FIG. 5).
[0068]
30 FIG. 9 is a sectional view illustrating a molding mold 80 used
to integrally mold the stator 1 and the shaft 7 with a mold resin.
[0069]
The molding mold 80 has an upper mold 81 which is a movable
mold, and a lower mold 82 which is a stationary mold. A cavity 83
17
is formed between the upper and lower molds 81 and 82. A gate 84 is
formed in the lower mold 82 for injecting a resin into the cavity 83.
[0070]
A core 85 having a columnar shape is formed in the lower mold
5 82, and the core 85 protrudes within the cavity 83. The core 85 is
a portion that engages with the inner side of the stator core 10. A
larger-diameter portion 86 is formed at the lower end of the core 85,
and the larger-diameter portion 86 protrudes outward in the radial
direction from the core 85. The larger-diameter portion 86 is a
10 portion corresponding to the opening 41 (FIG. 1) of the mold stator
4.
[0071]
FIG. 10 is a flowchart illustrating the manufacturing process
of the motor 100. First, a plurality of stacking elements are
15 stacked in the axial direction and fixed together by crimping or the
like, thereby forming the stator core 10 (step S101).
[0072]
Next, the insulators 2 are integrally molded with the stator
core 10 (step S102). That is, the upper mold 31 of the molding mold
20 30 illustrated in FIGS. 7 and 8 is moved upward to open the cavity
33, and the stator core 10 is placed in the cavity 33. Then, the
upper mold 31 is moved downward to close the cavity 33. In this
state, a resin such as PBT in a molten state is injected from the
cylinder 315 into the cavity 33 through the sprue 311, the runners
25 312, and the gates 313.
[0073]
Then, the resin in the cavity 33 is cured by cooling the
molding mold 30. Within the cavity 33, the resin cured in the
winding portion area 35 forms the winding portion 21, the resin
30 cured in the inner wall portion area 36 forms the inner wall portion
22, and the resin cured in the outer wall portion area 37 forms the
outer wall portion 23.
[0074]
After curing the resin in the cavity 33, the upper mold 31 of
18
the molding mold 30 is moved upward to open the cavity 33, and the
stator core 10 integrally molded with the insulators 2 is taken out
of the molding mold 30.
[0075]
5 Next, the coils 3 are wound on the stator core 10 via the
insulators 2 (step S103). In this stage, the stator core 10 is
expanded in a band shape, and thus the coils 3 can be easily wound
on the stator core 10.
[0076]
10 After the coils 3 are wound on the stator core 10, the stator
core 10 is bent in an annular shape and both ends of the stator core
10 are welded to each other, so that the stator 1 illustrated in FIG.
4 is formed.
[0077]
15 Next, the circuit board 43 is attached to the stator 1. The
stator 1 and the circuit board 43 are placed in the molding mold 80,
and the mold resin portion 40 is formed (step S104). Specifically,
the upper mold 81 of the molding mold 80 illustrated in FIG. 9 is
moved upward to open the cavity 83, and the stator 1 is placed in
20 the cavity 83. Thereafter, the upper mold 81 is moved downward to
close the cavity 83, and then the mold resin such as BMC is injected
into the cavity 83 through the gate 84. The mold resin injected
into the cavity 83 covers the outer circumferential side and the
counter-load side of the stator 1.
25 [0078]
In a case where a thermosetting resin is used as the mold
resin, after injecting the mold resin into the cavity 83, the mold
resin in the cavity 83 is cured by heating the molding mold 80.
Consequently, the manufacturing of the mold stator 4 in which the
30 stator 1 is covered with the mold resin portion 40 is completed.
[0079]
Aside from steps S101 to S104, the rotor 5 is formed.
Specifically, a plurality of stacking elements are stacked in the
axial direction and fixed together by crimping or the like, thereby
19
forming the rotor core 50. Then, the magnets 55 are inserted into
the magnet insertion holes 51. Further, the shaft 7, the rotor core
50, the magnets 55, and the sensor magnet 56 are integrally molded
with a resin which forms the resin portion 6. In this way, the
5 rotor 5 is formed.
[0080]
Thereafter, the bearings 71 and 72 are attached to the shaft 7
of the rotor 5, and the rotor 5 is inserted into the inside of the
stator 1 through the opening 41 of the mold stator 4 (step S106).
10 Further, the bracket 73 is attached to the opening 41 of the mold
stator 4, and the cap 74 is attached to the outside of the bracket
15. Consequently, the manufacturing of the motor 100 illustrated in
FIG. 1 is completed.
[0081]
15 In the manufacturing process of the motor 100 illustrated in
FIG. 10, steps S101 to S104 correspond to the manufacturing process
of the stator 1 (the manufacturing method of the stator 1).
[0082]
(Functions)
20 A resistance R of the coil 3 is expressed by ρ × L/S using a
resistivity ρ, a length L, and a cross-sectional area S of the coil
3. In other words, the resistance R of the coil 3 increases in
proportion to the length L of the coil 3. Therefore, as the length
per turn of the coil 3 wound around the tooth 12 (hereinafter
25 referred to as a winding length) decreases, the resistance R
decreases. As the resistance R decreases, the copper loss which is
one of the motor losses decreases, and thus the motor efficiency
increases. In order to shorten the winding length of the coil 3, it
is effective to reduce the thickness of the winding portion 21 of
30 the insulator 2 around which the coil 3 is wound.
[0083]
If the number of turns of the coil 3 is the same, as a wire
diameter of the coil 3 increases, the cross-sectional area S of the
coil 3 increases, and thus the resistance R decreases. The number
20
of turns of the coil 3 affects the maximum output of the motor 100.
Thus, after the number of turns of the coil 3 is determined, the
wire diameter of the coil 3 is generally selected to be as large as
possible within a range such that the coil 3 can be housed in the
5 slot 13.
[0084]
As the maximum thickness T3 of the side portion 21c of the
winding portion 21 of the insulator 2 is reduced, the slot 13 can be
made larger. In other words, reducing the maximum thickness T3 of
10 the side portion 21c of the winding portion 21 has the effect of
shortening the winding length of the coil 3 and has the effect of
increasing the cross-sectional area of the coil 3.
[0085]
In contrast, reducing the maximum thicknesses T1 and T2 of the
15 first end portion 21a and the second end portion 21b of the winding
portion 21 only contributes to the shortening of the winding length
of the coil 3. That is, the maximum thickness T3 of the winding
portion 21 in the circumferential direction has a greater
contribution to improvement in the motor efficiency than the maximum
20 thicknesses T1 and T2 of the winding portion 21 in the axial
direction.
[0086]
FIG. 11 shows simulation results regarding the contribution of
the maximum thicknesses T1, T2, and T3 to improvement in the motor
25 efficiency. The motor efficiency is a ratio (%) of an output
(rotational speed × torque) to a power input to the motor 100.
[0087]
In FIG. 11, a line E1 indicates a change in the motor
efficiency when the maximum thickness T3 is varied while the maximum
30 thicknesses T1 and T2 are set constant at 1 mm. A line E2 indicates
a change in the motor efficiency when the maximum thicknesses T1 and
T2 are varied while the maximum thickness T3 is set constant at 0.4
mm.
[0088]
21
A line E3 indicates a change in the motor efficiency when the
maximum thickness T1 is varied while the maximum thickness T2 is set
constant at 1 mm and the maximum thickness T3 is set constant at 0.4
mm. A line E4 indicates a change in the motor efficiency when the
5 maximum thickness T2 is varied while the maximum thickness T1 is set
constant at 1 mm and the maximum thickness T3 is set constant at 0.4
mm.
[0089]
From FIG. 11, it is understood that the motor efficiency is
10 most improved when the maximum thickness T3 is reduced as indicated
by the line E1.
[0090]
It is difficult to reduce all the maximum thicknesses T1, T2,
and T3 of the winding portion 21 of the insulator 2. Thus, in the
15 first embodiment, the maximum thickness T3 of the side portion 21c
is made the smallest, i.e., T3 < T1, T2 is satisfied. This enhances
the effect of improving the motor efficiency.
[0091]
However, the maximum thickness T3 of the side portion 21c of
20 the winding portion 21 is affected by a positional accuracy of the
stator core 10 which is placed in the molding mold 30, and thus
there is a limit to reduction in the maximum thickness T3. For this
reason, it is necessary to reduce the maximum thickness T1 of the
first end portion 21a or the maximum thickness T2 of the second end
25 portion 21b, in addition to the maximum thickness T3.
[0092]
In the molding step of the insulator 2, the thermoplastic
resin is heated and brought into a molten state in the cylinder 315,
and then injected into the cavity 33 through the sprue 311, the
30 runners 312, and the gates 313 as described with reference to FIG. 7.
[0093]
In general, the temperature of the molding mold 30 is much
lower than the temperature of the cylinder 315, and the temperature
of the stator core 10 is lower than or equal to the temperature of
22
the molding mold 30. Thus, as the resin flows through the sprue 311,
the runners 312, and the gates 313, the temperature of the resin
decreases.
[0094]
5 FIG. 12 illustrates a relationship between the temperature and
each of the viscosity and the fluidity of a thermoplastic resin.
From FIG. 12, it is understood that the viscosity and the fluidity
of the resin are reduced as the temperature of the resin decreases.
[0095]
10 When the resin is injected through the cylinder 315 into the
molding mold 30, molding pressure is applied to the resin. FIG. 13
shows the relationship between the molding pressure and the flow
length for three different resin thicknesses Ta, Tb, and Tc (Ta < Tb
< Tc). From FIG. 13, it is understood that, as the molding pressure
15 increases, the flow length increases. It is also understood that an
increase in the flow length with an increase in the molding pressure
is small when the resin thickness is small.
[0096]
As illustrated in FIG. 8, the gate 313 is open in the portion
20 361 for forming the first wall portion 22a (FIG. 5) of the inner
wall portion 22 in the cavity 33. In the cavity 33, as a position
gets closer to the gate 313, the temperature of the resin increases
and the molding pressure increases, and thus the fluidity of the
resin increases.
25 [0097]
Meanwhile, the thickness of the side portion 21c is the
smallest in the winding portion 21. Thus, when the resin passes
through a portion for forming the side portion 21c of the winding
portion 21 in the cavity 33, the heat of the resin is taken by the
30 molding mold 30 and the stator core 10, and thus the temperature of
the resin may decrease and the resin may be partially cured. Thus,
the molding pressure is less likely to be transmitted uniformly
throughout the entire cavity 33.
[0098]
23
From the above, it can be said that the fluidity of the resin
is higher at the gate 313 side in the cavity 33 than at the opposite
side to the gate 313 in the cavity 33, and thus the gate 313 side in
the cavity 33 is more suitable for thinning.
5 [0099]
For this reason, in the first embodiment, the maximum
thickness T1 of the first end portion 21a closer to the gate 313 is
made smaller than the maximum thickness T2 of the second end portion
21b farther from the gate 313. In other words, the maximum
10 thicknesses T1, T2, and T3 satisfy T3 < T1 < T2 to achieve the
thinning of the insulator 2.
[0100]
FIG. 14 is a schematic diagram illustrating how much the
maximum thicknesses T1, T2, and T3 of the insulator 2 can be reduced
15 in the first embodiment where T3 < T1 < T2 is satisfied, in
comparison with a comparison example where T3 < T2 < T1 is satisfied.
[0101]
As described above, the second end portion 21b of the winding
portion 21 is far from the gate 313, and thus the fluidity of the
20 resin is low at the second end portion 21b. Thus, when the maximum
thickness T2 of the second end portion 21b is intended to be reduced,
the resin does not sufficiently spread over the second end portion
21b, which may cause molding defects.
[0102]
25 In contrast, the first end portion 21a of the winding portion
21 is close to the gate 313 and thus the fluidity of the resin is
high. Thus, molding defects do not occur even when the maximum
thickness T1 of the first end portion 21a is reduced. Therefore,
the maximum thickness T1 of the first end portion 21a can be reduced
30 effectively.
[0103]
The gate 313 leaves the gate mark G, which is a concave
portion or a convex portion, on the surface of the first wall
portion 22a (FIG. 5) of the inner wall portion 22 of the insulator 2.
24
The location of the gate mark G is not limited to the first wall
portion 22a of the inner wall portion 22. The gate mark G may be
formed on the first wall portion 23a of the outer wall portion 23.
[0104]
5 (Effects of Embodiment)
As described above, in the first embodiment, the winding
portion 21 of the insulator 2 has the first end portion 21a located
at one side of the tooth 12 in the circumferential direction, the
second end portion 21b located at the other side of the tooth 12 in
10 the axial direction, and the side portion 21c located at one side of
the tooth 12 in the circumferential direction. The maximum
thickness T1 of the first end portion 21a in the axial direction,
the maximum thickness T2 of the second end portion 21b in the axial
direction, and the maximum thickness T3 of the side portion 21c in
15 the circumferential direction satisfy T3 < T1 < T2. The insulator 2
has the gate mark G on the same side as the first end portion 21a in
the axial direction. Consequently, the thickness of the insulator 2
can be reduced effectively, and thus the winding density of the
coils 3 can be improved and the motor efficiency can be improved.
20 [0105]
Second Embodiment
Next, a second embodiment will be described. FIG. 15 is a
sectional view illustrating the tooth 12, the winding portion 21 of
an insulator 2A, and the coil 3 in the second embodiment. The
25 winding portion 21 of the insulator 2A has the first end portion 21a,
the second end portion 21b, and the side portions 21c as in the
first embodiment.
[0106]
As in the insulator 2 of the first embodiment, the maximum
30 thicknesses T1, T2, and T3 of the first end portion 21a, the second
end portion 21b, and the side portion 21c of the winding portion 21
of the insulator 2A satisfy T3 < T1 < T2, and the gate mark G (FIG.
5) is provided on the same side as the first end portion 21a in the
axial direction.
25
[0107]
In the second embodiment, the outer circumferential surface
211 of the first end portion 21a is a curved surface projecting on a
side opposite to the tooth 12 in the axial direction. Further, the
5 outer circumferential surface 211 is an arc-shaped surface having a
radius of curvature RT1 in a plane perpendicular to the extending
direction of the tooth 12.
[0108]
The outer circumferential surface 212 of the second end
10 portion 21b is a curved surface projecting on a side opposite to the
tooth 12 in the axial direction. Further, the outer circumferential
surface 212 is an arc-shaped surface having a radius of curvature
RT2 in a plane perpendicular to the extending direction of the tooth
12.
15 [0109]
The radius of curvature RT1 of the outer circumferential
surface 211 of the first end portion 21a and the radius of curvature
RT2 of the outer circumferential surface 212 of the second end
portion 21b satisfy RT1 > RT2.
20 [0110]
If the radius of curvature RT1 is small, the thickness of a
corner portion 213 between the first end portion 21a and the side
portion 21c may be extremely small when the maximum thickness T1 of
the first end portion 21a is reduced. Thus, the resin may not
25 spread over the entire insulator 21A during molding, which may cause
molding defects.
[0111]
In the second embodiment, the radius of curvature RT1 of the
outer circumferential surface 211 of the first end portion 21a is
30 larger than the radius of curvature RT2 of the outer circumferential
surface 212 of the second end portion 21b. Thus, the corner
portions 213 are prevented from being extremely thin even when the
maximum thickness T1 of the first end portion 21a of the winding
portion 21 is reduced. Thus, occurrence of molding defects is
26
suppressed.
[0112]
The motor of the second embodiment is configured in the same
manner as the motor 100 of the first embodiment except for the
5 above-described points.
[0113]
As described above, in the second embodiment, the radius of
curvature RT1 of the outer circumferential surface 211 of the first
end portion 21a of the winding portion 21 of the insulator 2A and
10 the radius of curvature RT2 of the outer circumferential surface 212
of the second end portion 21b of the insulator 2A satisfy RT1 > RT2.
Thus, the maximum thickness T1 of the first end portion 21a of the
winding portion 21 of the insulator 2A can be further reduced
without causing molding defects. Consequently, the winding density
15 of the coils 3 can be improved, and the motor efficiency can be
improved.
[0114]
The outer circumferential surface 211 of the first end portion
21a and the outer circumferential surface 212 of the second end
20 portion 21b are described as arc-shaped curved surfaces. However,
the outer circumferential surfaces 211 and 212 are not necessarily
arc-shaped surfaces, and only need to be curved surfaces whose radii
of curvature are defined.
[0115]
25 The maximum thicknesses T1, T2, and T3 of the winding portion
21 of the insulator 2A have been described to satisfy T3 < T1 < T2.
However, in the second embodiment, the effect of reducing the
maximum thickness T1 can be obtained as long as RT1 > RT2 and T1 <
T2 are satisfied.
30 [0116]
Third Embodiment
Next, a third embodiment will be described. FIG. 16(A) is a
sectional view illustrating the tooth 12, the winding portion 21 of
an insulator 2B, and the coil 3 in the third embodiment. The
27
winding portion 21 of the insulator 2B has the first end portion 21a,
the second end portion 21b, and the side portions 21c as in the
first embodiment.
[0117]
5 As in the insulator 2 of the first embodiment, the maximum
thicknesses T1, T2, and T3 of the first end portion 21a, the second
end portion 21b, and the side portion 21c of the winding portion 21
of the insulator 2B satisfy T3 < T1 < T2, and the gate mark G (FIG.
5) is provided on the same side as the first end portion 21a in the
10 axial direction.
[0118]
The insulator 2B of the third embodiment has corner portions
213 as first corner portions between the first end portion 21a and
the side portions 21c. As illustrated in FIG. 16(C) in an enlarged
15 scale, each corner portion 213 is an arc-shaped surface having a
radius of curvature R1 in a plane perpendicular to the extending
direction of the tooth 12.
[0119]
The insulator 2B has corner portions 214 as second corner
20 portions between the second end portion 21b and the side portions
21c. As illustrated in FIG. 16(B) in an enlarged scale, each corner
portion 214 is an arc-shaped surface having a radius of curvature R2
in a plane perpendicular to the extending direction of the tooth 12.
[0120]
25 The radius of curvature R1 of the corner portion 213 and the
radius of curvature R2 of the corner portion 214 satisfy R1 < R2.
[0121]
Since the insulator 2B is molded using the molding mold 30
(FIG. 7), the corner portions 213 and 214 of the winding portion 21
30 are both curved surfaces because of the shape constraints of the
molding mold. Meanwhile, since the tooth 12 is formed of a
laminated body of punched stacking steel sheets, the tooth 12 has
four corners of right angles in the section.
[0122]
28
Therefore, if the radius of curvature of each corner portion
213 of the insulator 2B is large, the thickness of the corner
portion 213 covering the corner of the tooth 12 may be extremely
small when the maximum thickness T1 of the first end portion 21a is
5 reduced. In other words, the resin may not spread over the entire
insulator 2B during molding.
[0123]
In the third embodiment, the radius of curvature R1 of each
corner portion 213 on the first end portion 21a side is smaller than
10 the radius of curvature R2 of each corner portion 214 on the second
end portion 21b side. Consequently, the thicknesses of the corner
portions 213 covering the corners of the tooth 12 are prevented from
being extremely small, and thus occurrence of molding defects can be
suppressed.
15 [0124]
Further, the radius of curvature R1 of the corner portion 213
and the maximum thickness T1 of the first end portion 21a satisfy R1
≤ T1.
[0125]
20 If the radius of curvature R1 of each corner portion 213 is
larger than the maximum thickness T1 of the first end portion 21a,
the thickness of the corner portion 213 covering the corner of the
tooth 12 may be smaller than the thickness of the side portion 21c
in the case where the outer circumferential surface 211 of the first
25 end portion 21a is close to a flat surface. In other words, the
resin may not spread over the entire insulator 2B during molding.
[0126]
In the third embodiment, the radius of curvature R1 of each
corner portion 213 is smaller than or equal to the maximum thickness
30 T1 of the first end portion 21a. Therefore, even when the outer
circumferential surface 211 of the first end portion 21a is close to
a flat surface, the thickness of the corner portion 213 can be kept
at a thickness with which resin molding is possible.
[0127]
29
As described in the second embodiment, the outer
circumferential surfaces 211 and 212 of the first end portion 21a
and the second end portion 21b may be arc-shaped curved surfaces,
and their radii of curvature RT1 and RT2 (FIG. 15) may satisfy RT1 >
5 RT2.
[0128]
The motor of the third embodiment is configured in the same
manner as the motor 100 of the first embodiment except for the
above-described points.
10 [0129]
As described above, in the third embodiment, the radius of
curvature R1 of the corner portion 213 between the first end portion
21a and the side portion 21c is smaller than the radius of curvature
R2 of the corner portion 214 between the second end portion 21b and
15 the side portion 21c. Thus, the maximum thickness T1 of the first
end portion 21a of the winding portion 21 of the insulator 2B can be
further reduced while suppressing occurrence of molding defects.
Therefore, the winding density of the coils 3 can be improved, and
the motor efficiency can be improved.
20 [0130]
(Air Conditioner)
Next, an air conditioner to which the motor of each of the
above-described embodiments is applicable will be described. FIG.
17(A) is a diagram illustrating a configuration of an air
25 conditioner 500 to which the motor 100 of the first embodiment is
applied. The air conditioner 500 includes an outdoor unit 501, an
indoor unit 502, and a refrigerant pipe 503 that connects the units
501 and 502.
[0131]
30 The outdoor unit 501 includes an outdoor fan 510 which is, for
example, a propeller fan. The indoor unit 502 includes an indoor
fan 520 which is, for example, a cross flow fan. The outdoor fan
510 includes the impeller 505 and the motor 100 driving the impeller
505. The indoor fan 520 includes an impeller 521 and the motor 100
30
that drives the impeller 521. Both the motors 100 have the
configuration described in the first embodiment. FIG. 17(A) also
illustrates a compressor 504 that compresses refrigerant.
[0132]
5 FIG. 17(B) is a sectional view of the outdoor unit 501. The
motor 100 is supported by a frame 509 disposed in a housing 508 of
the outdoor unit 501. The impeller 505 is attached to the shaft 7
of the motor 100 via a hub 506.
[0133]
10 In the outdoor fan 510, the impeller 505 attached to the shaft
7 rotates by the rotation of the rotor 5 of the motor 100 to blow
air to the outdoors. During a cooling operation, heat released when
the refrigerant compressed by the compressor 504 is condensed in a
condenser (not illustrated) is discharged to the outdoors by the air
15 blown from the outdoor fan 510. Similarly, in the indoor fan 520
(FIG. 17(A)), the impeller 521 rotates by the rotation of the rotor
5 of the motor 100 to blow air from which heat is taken in an
evaporator (not shown), to the indoors.
[0134]
20 The motor 100 of the above-described first embodiment has high
motor efficiency because of the improved winding density of the
coils 3. Thus, the operation efficiency of the air conditioner 500
can be improved.
[0135]
25 Instead of the motor 100 of the first embodiment, the motor of
the second or third embodiment may be used. Although the motor 100
is used as a driving source of the outdoor fan 510 and as a driving
source of the indoor fan 520 in this example, it is sufficient that
that the motor 100 is used as at least one of the driving sources.
30 [0136]
The motor 100 of each embodiment can also be mounted on any
electric apparatuses other than the fan of the air conditioner.
[0137]
Although the desirable embodiments of the present invention
31
have been specifically described above, the present invention is not
limited to the above-described embodiments, and various
modifications or changes may be made to those embodiments without
departing from the scope of the present invention.
5 DESCRIPTION OF REFERENCE CHARACTERS
[0138]
1 stator; 2, 2A, 2B insulator; 3 coil; 4 mold stator; 5
rotor; 6 resin portion; 7 shaft; 10 stator core; 10A connecting
core; 11 yoke; 12 tooth; 13 slot; 21 winding portion; 21a first
10 end portion; 21b second end portion; 21c side portion; 22 inner
wall portion; 22a first wall portion; 22b second wall portion;
22c side wall portion; 23 outer wall portion; 23a first wall
portion; 23b second wall portion; 23c side wall portion; 30
molding mold; 31 upper mold; 32 lower mold; 33 cavity; 40 mold
15 resin portion; 41 opening; 42 bearing support portion; 43 circuit
board; 44 magnetic sensor; 50 rotor core; 51 magnet insertion
hole; 55 magnet; 56 sensor magnet; 80 molding mold; 81 upper
mold; 82 lower mold; 83 cavity; 100 motor; 211 curved surface;
212 curved surface; 311 sprue; 312 runner; 313 gate; 315
20 cylinder; 500 air conditioner; 501 outdoor unit; 502 indoor unit;
503 refrigerant pipe; 504 compressor; 505 impeller; 510 outdoor
fan; 520 indoor fan; 521 impeller.

32
We Claim :
1. A stator comprising:
a stator core having a yoke extending in a circumferential
direction about an axis and a tooth extending from the yoke toward
5 the axis;
an insulator having a winding portion surrounding the tooth;
and
a coil wound around the winding portion of the insulator,
wherein the winding portion of the insulator has a first end
10 portion located at one side of the tooth in a direction of the axis,
a second end portion located at the other side of the tooth in the
direction of the axis, and a side portion located at one side of the
tooth in the circumferential direction,
wherein the first end portion has a maximum thickness T1 in
15 the direction of the axis, the second end portion has a maximum
thickness T2 in the direction of the axis, and the side portion has
a maximum thickness T3 in the circumferential direction,
wherein the maximum thicknesses T1, T2 and T3 satisfy T3 < T1
< T2, and
20 wherein the insulator has a gate mark on the same side as the
first end portion in the direction of the axis.
2. A stator comprising:
a stator core having a yoke extending in a circumferential
25 direction about an axis and a tooth extending from the yoke toward
the axis;
an insulator having a winding portion surrounding the tooth;
and
a coil wound around the winding portion of the insulator,
30 wherein the winding portion of the insulator has a first end
portion located at one side of the tooth in a direction of the axis,
a second end portion located at the other side of the tooth in the
direction of the axis, and a side portion located at one side of the
tooth in the circumferential direction,
33
wherein the first end portion has a maximum thickness T1 in
the direction of the axis, and the second end portion has a maximum
thickness T2 in the direction of the axis,
wherein the first end portion has a curved surface having a
5 radius of curvature RT1 and projecting on a side opposite to the
tooth, and the second end portion has a curved surface having a
radius of curvature RT2 and projecting on a side opposite to the
tooth,
wherein the maximum thicknesses T1, T2 and T3 satisfy T1 < T2,
10 and
wherein the radii of curvature RT1 and RT2 satisfy RT1 > RT2,
and
wherein the insulator has a gate mark on the same side as the
first end portion in the direction of the axis.
15
3. The stator according to claim 2, wherein the side portion has
a maximum thickness T3 in the circumferential direction, and
wherein the maximum thicknesses T1, T2 and T3 satisfy T3 < T1
< T2.
20
4. The stator according to any one of claims 1 to 3, wherein the
winding portion of the insulator has a corner portion having a
radius of curvature R1 between the first end portion and the side
portion, and a corner portion having a radius of curvature R2
25 between the second end portion and the side portion, and
wherein the radii of curvature R1 and R2 satisfy R1 < R2.
5. The stator according to claim 4, wherein the radius of
curvature R1 and the maximum thickness T1 satisfy R1 ≤ T1.
30
6. The stator according to any one of claims 1 to 5, wherein the
insulator has an inner wall portion located at an inner end of the
tooth in a radial direction about the axis and an outer wall portion
located at an outer end of the tooth in the radial direction, and
34
wherein the gate mark is formed at the inner wall portion.
7. The stator according to any one of claims 1 to 6, wherein the
insulator is formed of a thermoplastic resin.
5
8. The stator according to any one of claims 1 to 7, further
comprising a mold resin portion covering the stator.
9. A motor comprising:
10 the stator according to any one of claims 1 to 8; and
a rotor surrounded by the stator and rotatable about the axis.
10. A fan comprising:
the motor according to claim 9; and
15 an impeller driven to rotate by the motor.
11. An air conditioner comprising an outdoor unit and an indoor
unit connected with the outdoor unit via a refrigerant pipe,
wherein at least one of the outdoor unit and the indoor unit
20 comprises the fan according to claim 10.
12. A manufacturing method of a stator, the method comprising the
steps of:
preparing a stator core having a yoke extending in a
25 circumferential direction about an axis and a tooth extending from
the yoke toward the axis;
forming an insulator using a molding mold, the insulator
having a winding portion surrounding the tooth; and
winding a coil around the winding portion of the insulator,
30 wherein in the forming step of the insulator, a first end
portion of the winding portion is formed at one side of the tooth in
a direction of the axis, a second end portion of the winding portion
is formed at the other side of the tooth in the direction of the
axis, and a side portion of the winding portion is formed at one
35
side of the tooth in the circumferential direction,
wherein the first end portion has a maximum thickness T1 in
the direction of the axis, the second end portion has a maximum
thickness T2 in the direction of the axis, and the side portion has
5 a maximum thickness T3 in the circumferential direction,
wherein the maximum thicknesses T1, T2 and T3 satisfy T3 < T1
< T2, and
wherein the molding mold has a gate on the same side as a
portion for forming the first end portion in the direction of the
10 axis.
13. A manufacturing method of a stator, the method comprising the
steps of:
preparing a stator core having a yoke extending in a
15 circumferential direction about an axis and a tooth extending from
the yoke toward the axis;
forming an insulator using a molding mold, the insulator
having a winding portion surrounding the tooth; and
winding a coil around the winding portion of the insulator,
20 wherein in the forming step of the insulator, a first end
portion of the winding portion is formed at one side of the tooth in
a direction of the axis, a second end portion of the winding portion
is formed at the other side of the tooth in the direction of the
axis, and a side portion of the winding portion is formed at one
25 side of the tooth in the circumferential direction,
wherein the first end portion has a maximum thickness T1 in
the direction of the axis, and the second end portion has a maximum
thickness T2 in the direction of the axis,
wherein the first end portion has a curved surface having a
30 radius of curvature RT1 and projecting on a side opposite to the
tooth, and the second end portion has a curved surface having a
radius of curvature RT2 and projecting on a side opposite to the
tooth,
wherein the maximum thicknesses T1, T2 and T3 satisfy T1 < T2,

wherein the radii of curvature RT1 and RT2 satisfy RT1 > RT2,
and
wherein the molding mold has a gate on the same side as a
portion for forming the first end portion in the direction of the
5 axis.