U.S. patent application number 11/161248 was filed with the patent office on 2006-02-02 for motor stator and motor.
This patent application is currently assigned to Nidec Corporation. Invention is credited to Motofumi Otsuji.
Application Number | 20060022549 11/161248 |
Document ID | / |
Family ID | 35731323 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060022549 |
Kind Code |
A1 |
Otsuji; Motofumi |
February 2, 2006 |
Motor Stator and Motor
Abstract
Motor stator in which a plurality of first guide grooves (321)
and second guide grooves (322) that govern the winding position of
conductors are formed on the upper end portion and lower end
portion of insulators (32) which cover each of the stator teeth
(31). The inclination of the first guide grooves is equal to the
pitch of the first guide grooves, and the inclination of the second
guide grooves is configured to be 0. The second-guide-groove start
and end points are positioned on a straight line extending in the
(-Z) direction from the first-guide-groove end point (3212) and
from the adjoining first-guide-groove start point (3211) on the
(-Y) side.
Inventors: |
Otsuji; Motofumi; (Kyoto,
JP) |
Correspondence
Address: |
JUDGE PATENT FIRM;RIVIERE SHUKUGAWA 3RD FL.
3-1 WAKAMATSU-CHO
NISHINOMIYA-SHI, HYOGO
662-0035
JP
|
Assignee: |
Nidec Corporation
338 Kuze Tonoshiro-cho Minami-ku
Kyoto
JP
|
Family ID: |
35731323 |
Appl. No.: |
11/161248 |
Filed: |
July 27, 2005 |
Current U.S.
Class: |
310/216.001 |
Current CPC
Class: |
H02K 3/522 20130101;
H02K 3/325 20130101 |
Class at
Publication: |
310/216 |
International
Class: |
H02K 1/00 20060101
H02K001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2004 |
JP |
JP-2004-218197 |
Jul 4, 2005 |
JP |
JP-2005-194673 |
Claims
1. An electric motor stator comprising: a plurality of teeth
disposed in a radial form centered about a predetermined center
axis; insulators respectively covering said plurality of teeth,
along an upper end portion of said insulators that covers an upper
end-one end in an orientation paralleling the center axis--of each
of said plurality of teeth, said insulators being provided with a
plurality of upper guide grooves rowed parallel to each other at a
pitch approximately equal to the diameter of the conductors, for
governing the wind-on position of the conductors; and a plurality
of coils provided on each of said plurality of teeth by winding
conductors onto said insulators through to multiple layers.
2. A motor stator as set forth in claim 1, wherein in each of said
plurality of coils: on flanks, parallel to the center axis, of said
teeth, first layer conductors and second layer conductors wound on
said first layer conductors are arranged parallel to one another;
and in the upper end of said teeth, said first layer conductors and
said second layer conductors cross each other.
3. A motor stator as set forth in claim 2, wherein: along each
flank of said teeth, said first layer conductor and said second
layer conductors are parallel to the center axis; and in said upper
end, said first layer conductors and said second layer conductors
are angled with respect to a plane parallel to the center axis and
perpendicular to said teeth.
4. A motor stator set forth in claim 2, wherein the plurality of
upper guide grooves is formed at an incline with respect to a plane
parallel to a center axis and perpendicular to said teeth.
5. A motor stator set forth in claim 4, wherein in the conductors
as wound, the difference in radial distance from the center axis to
the beginning and to the end of a one of the upper guide grooves is
said pitch or less.
6. A motor stator set forth in claim 4, wherein the angle of
inclination of each of the plurality of upper guide grooves with
respect to a plane parallel to the center axis and perpendicular to
said teeth is from 5.degree. to 20.degree..
7. A stator motor set forth in claim 1, wherein: said insulators,
in lower end portions thereof covering the lower ends of each of
said plurality of teeth, are further provided with a plurality of
guide grooves, arranged in parallel at said pitch, for governing
the wind-on position of the conductors; and in the conductors as
wound, the end of a one of the upper guide grooves and the
beginning of a one of the lower guide grooves are formed on a
straight line parallel to the center axis, and the end of a one of
the lower guide grooves and the beginning of another of the upper
guide grooves adjoining said one of the upper guide grooves are
formed on a straight line parallel to the center axis.
8. A motor stator as set forth in claim 7, wherein the difference
in radial distance from the center axis to the respective
beginnings and ends of the plurality of upper guide grooves is said
pitch or less.
9. A motor stator as set forth in claim 8, wherein: the difference
in radial distance from the center axis to the respective
beginnings and ends of the plurality of upper guide grooves is
equal to said pitch; and the radial distances from the center axis
to the respective beginnings and ends of the plurality of lower
guide grooves are equal.
10. A motor stator as set forth in claim 8, wherein: the difference
in radial distance from the center axis to the respective
beginnings and ends of the plurality of upper guide grooves and the
plurality of lower guide grooves is equal to one-half said pitch;
and said insulators further comprise first partitions covering,
along an orientation paralleling the center axis, said plurality of
teeth from the center to the end with the plurality of upper guide
grooves; and a second partition covering said plurality of teeth
from the said center to the end with the plurality of lower guide
grooves.
11. A motor stator as set forth in claim 8, wherein the angle of
inclination of each of the plurality of upper guide grooves with
respect to a plane parallel to the center axis and perpendicular to
said teeth is from 5.degree. to 20.degree..
12. An electric motor comprising: a first assembly having a stator
as set forth in claim 1; a second assembly disposed opposing said
stator, and having a field magnet for generating between said
second assembly and said stator rotational force centered on the
center axis; and a bearing mechanism for supporting said second
assembly to enable it to rotate relative to said first assembly,
centered on the center axis.
13. An electric motor stator comprising: a plurality of teeth
disposed in a radial form centered about a predetermined center
axis; insulators respectively covering said plurality of teeth; and
a plurality of coils provided on each of said plurality of teeth by
winding conductors onto said insulators through to multiple layers;
wherein along an upper end portion of said insulators that covers
an upper end--one end in an orientation paralleling the center
axis--of each of said plurality of teeth, said insulators are
provided, on the center-axis side of the tooth, or on the side
thereof opposite the center axis, with a first protruding wall
extending in the orientation in which the conductors are layered,
and bulging radially; and said first protruding wall is disposed
paralleling the orientation in which conductors in a first layer of
a coil in the upper end portion of said insulators are wound, and
is furnished with a feature for coming into contact with said first
layer to govern the wind-on position of the conductors in said
first layer.
14. A motor stator as set forth in claim 13, wherein said first
protruding wall is disposed paralleling the orientation in which
conductors in a second layer of said coil are wound, and is
furnished with a feature for coming into contact with said second
layer to govern the wind-on position of the conductors in said
second layer.
15. A motor stator as set forth in claim 13, wherein: said
insulators in the upper end portion thereof are further provided
with a second protruding wall opposite said first protruding wall
across the tooth, extending in the orientation in which the
conductors are layered and bulging radially; and said second
protruding wall is disposed paralleling the orientation in which
the conductors in said first layer of a coil in the upper end
portion of said insulators are wound, is furnished with a feature
for coming into contact with said first layer to govern the wind-on
position of the conductors in said first layer.
16. A motor stator as set forth in claim 15, wherein said second
protruding wall is disposed paralleling the orientation in which
conductors in a second layer of said coil in the upper end portion
of said insulators are wound, and is further furnished with a
feature for coming into contact with said second layer to govern
the wind-on position of the conductors in said second layer.
17. A motor stator as set forth in claim 13, wherein in each of
said plurality of coils: on flanks, parallel to the center axis, of
said teeth, first layer conductors and second layer conductors on
said first layer conductors are arranged parallel to one another;
and in the upper end of said teeth, said first layer conductors and
said second layer conductors cross each other.
18. A motor stator as set forth in claim 17, wherein: along each
flank of said teeth, said first layer conductors and said second
layer conductors are parallel to the center axis; and in said upper
end, said first layer conductors and said second layer conductors
are angled with respect to a plane parallel to the center axis and
perpendicular to said teeth.
19. A motor stator as set forth in claim 13, further comprising: a
plurality of tooth inner edge portions provided at the leading end
of the center-axis side of each of said plurality of teeth, and,
centered on the center axis, flaring along the perimeter to both
sides of the teeth; wherein in each of the inner edge portions of
said insulators that cover the surface of the inner edge portions
of the plurality of teeth on the side opposite the center-axis
side, said insulators are provided with inner-edge-portion guide
grooves for governing the wind-on position of the conductors.
20. A motor stator as set forth in claim 13, wherein in insulator
edge portions where upper end surfaces, being upper ends of each of
said insulators, and flanks of said insulators, covering each flank
of said plurality of teeth, are connected to each other, a
plurality of edge grooves for governing the wind-on position of the
first layer conductors in said coil is provided.
21. A motor stator as set forth in claim 20 wherein said insulators
along an upper end portion thereof are further provided with a
plurality of upper guide grooves rowed parallel to each other at a
pitch approximately equal to the diameter of the conductors, for
governing the wind-on position of the conductors.
22. A motor stator as set forth in claim 21, wherein: said
insulators, in lower end portions thereof covering the lower ends
of each of said plurality of teeth, are further provided with a
plurality of guide grooves, arranged in parallel at said pitch, for
governing the wind-on position of the conductors; and in the
conductors as wound, the end of a one of the upper guide grooves
and the beginning of a one of the lower guide grooves are
positioned on a straight line parallel to the center axis, and the
end of a one of the lower guide grooves and the beginning of
another of the upper guide grooves adjoining said one of the upper
guide grooves are formed on a straight line parallel to the center
axis.
23. A motor stator as set forth in claim 13, wherein in upper end
portions, being upper ends of each of said insulators, a plurality
of upper guide grooves rowed parallel to each other at a pitch
approximately equal to the diameter of the conductors is furnished
for governing the wind-on position of the conductors.
24. An electric motor comprising: a first assembly having a stator
as set forth in claim 13; a second assembly disposed opposing said
stator, and having a field magnet for generating between said
second assembly and said stator rotational force centered on the
center axis; and a bearing mechanism for supporting said second
assembly to enable it to rotate relative to said first assembly,
centered on the center axis.
25. An electric motor stator comprising: a plurality of teeth
disposed in a radial form centered about a predetermined center
axis; a plurality of tooth inner edge portions provided at the
leading end of the center-axis side of each of said plurality of
teeth, and, centered on the center axis, flaring along the
perimeter to both sides of the teeth insulators respectively
covering said plurality of teeth; and a plurality of coils provided
on each of said plurality of teeth by winding conductors onto said
insulators through to multiple layers; wherein in each of the inner
edge portions of said insulators that cover the surface of the
inner edge portions of the plurality of teeth on the side opposite
the center-axis side, said insulators are provided with
inner-edge-portion guide grooves for governing the wind-on position
of the conductors.
26. A motor stator as set forth in claim 25, wherein in each of
said plurality of coils: on flanks, parallel to the center axis, of
said teeth, first layer conductors and second layer conductors
wound on said first layer conductors are arranged parallel to one
another; and in the upper end of said teeth, said first layer
conductors and said second layer conductors cross each other.
27. A motor stator as set forth in claim 26, wherein: along each
flank of said teeth, said first layer conductors and said second
layer conductors are parallel to the center axis; and in said upper
end, said first layer conductors and said second layer conductors
are angled with respect to a plane parallel to the center axis and
perpendicular to said teeth.
28. A motor stator as set forth in claim 25, wherein
inner-edge-portion guide grooves engage the first windings among
the conductors in said second layer and in subsequent layers.
29. A motor stator as set forth in claim 28, wherein the conductors
in said first layer are wound on said insulator from the side
opposite the center axis toward the center axis, and the conductors
the subsequent second layer are wound on said insulator from the
center axis toward the side opposite the center axis.
30. An electric motor comprising: a first assembly having a stator
as set forth in claim 25; a second assembly disposed opposing said
stator, and having a field magnet for generating between said
second assembly and said stator rotational force centered on the
center axis; and a bearing mechanism for supporting said second
assembly to enable it to rotate relative to said first assembly,
centered on the center axis.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to electrically powered
motors, and in particular, to stators.
[0003] 2. Description of the Related Art
[0004] Electrically powered motors to date have been furnished with
a stator, and with magnetic-field producing magnets, which are the
drive part that rotates a motor's rotor section relative to its
stator section. Stators include an annular core, insulators as
nonconducting components that cover teeth sections of the core, and
coils formed by wrapping conductors onto the insulators. In
midsized motors such as are used for "electric power steering
systems" (as termed in, for example, U.S. Pat. App. Pub. No.
2002/0175574, but also referred to as "steer-by-wire systems"),
conductors of relatively large diameter are wrapped around
insulators and employed as the coils.
[0005] In such motors, owing to the fact that motor efficiency
increases with conductor diameter, technology for improving the
slot-fill factor of the coils by wrapping on the conductors in
regular rows without gaps is paramount. In the present
specification, the term "space factor" (as termed in, for example,
paragraph [0006] of both U.S. Pat. App. Pub. No. 2004/0263015 and
Pat. App. Pub. No. 2005/0029894, but also referred to as "slot-fill
factor," or "slot-fill ratio") is intended to mean the ratio of the
area occupied by the conductors with respect to the cross-sectional
area in the interval (slot) between adjoining stator teeth.
[0006] In stator implementations employing large-diameter
conductors that do not bend readily, when the conductors are wound
onto the teeth, it can happen that a conductor, as wrapped onto a
tooth from one flank to the other flank, does not bend fully around
a terminus of the tooth, and is instead left riding up off the
tooth, not lying in full contact along the flanks. For example, in
stator implementations in which the insulators are formed with
tooth-flank guide grooves, it can happen that the conductors fail
to be guided by the guide grooves, which is prohibitive not only of
attaining evenly-rowed wrapping but also of smooth conductor
windings, and limits improvement in the slot-fill factor of the
coils.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention makes it possible to build coils
smoothly onto an electric motor stator. The present invention also
makes it possible to reduce the thickness of coils on stator
insulator surfaces, and to prevent the conductors from separating
from the insulators.
[0008] In one example of the present invention, an electric motor
stator comprises multiple teeth radially arrayed and centered on a
specified center axis, insulators respectively covering said
multiple teeth, and multiple coils constructed by winding multiple
layers of conductors on said multiple teeth starting from said
insulators. In an top end section which covers an top end and forms
one end in a direction along the respective center axes of said
multiple teeth, said insulator is provided with multiple upper
guide grooves which are arrayed in parallel to one another at a
pitch approximately equal to the diameter of said conductor, and
which restrict the winding position of said conductor.
[0009] In another example of the present invention, the motor
stator is provided with multiple teeth radially arrayed and
centered on a specified center axis, insulators respectively
covering said multiple teeth, and multiple coils constructed by
winding multiple layers of conductors starting from said
insulators. At the top end section which covers the top end which
forms one end in a direction along the respective center axes of
said multiple teeth, said insulators are provided with a protruding
wall which extends in the conductor laminar direction on said
center axis side of said teeth, or on the opposite side of said
center axis, and which is convex toward said teeth. Said protruding
wall is constructed along the winding direction of said top end
portion of the coil first layer conductor, and contacts said first
layer to restrict the winding position of said conductor.
[0010] In yet another example of the present invention, the motor
stator comprises multiple teeth radially arrayed and centered on a
specified center axis; multiple teeth inside end sections disposed
at the respective end sections on said center axis side of said
multiple teeth, while opening on both sides of the teeth in a
circumferential direction with respect to the center of said center
axis; insulators respectively covering said multiple teeth; and
multiple coils constructed by winding multiple layers of conductors
starting at said insulators. Said insulators comprise inside end
guide grooves which restrict the winding position of said
conductors at the inside end sections which cover the surfaces on
the side opposite to that of the respective said center axes of
said multiple teeth inside end sections.
[0011] The present invention permits the smooth construction of
coils. In particular, it enables the smooth construction of coils
by preventing conductor mis-winding at the top end of the multiple
teeth.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] FIG. 1 is a vertical section illustrating a motor according
to a first embodiment of the present invention;
[0013] FIG. 2 is a plan view illustrating a stator;
[0014] FIG. 3 illustrates the stator in a bottom view;
[0015] FIG. 4 is a plan view depicting an insulator;
[0016] FIG. 5 depicts the insulator in an underside view;
[0017] FIG. 6 illustrates the insulator in a lateral view;
[0018] FIG. 7 is an oblique view of the insulator;
[0019] FIG. 8 is a partially sectional view depicting a first
partition;
[0020] FIG. 9 is a partially sectional view illustrating a second
partition;
[0021] FIG. 10 is a plan view showing a coil first layer;
[0022] FIG. 11 is a bottom view showing the coil first layer;
[0023] FIG. 12 is a plan view showing a coil second layer;
[0024] FIG. 13 is a diagram illustrating a cross-section through
coils on the flanks of insulators, wherein a winding machine nozzle
is represented in phantom;
[0025] FIG. 14 is a plan view depicting a motor insulator involving
a second embodiment of the present invention;
[0026] FIG. 15 illustrates the insulator in a bottom view;
[0027] FIG. 16 is a partially sectional view showing a first
partition for a motor involving a third embodiment of the present
invention;
[0028] FIG. 17 is a partially sectional view depicting a second
partition; and
[0029] FIG. 18 is a fragmentary enlarged sectional view
illustrating an end portion of the first partition.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Below preferred embodiments of the present invention will be
explained with reference to figures. In the descriptions that
follow, references to the positional relationships of each of the
parts, or to upper, lower, right and left directions, etc. will in
all cases be for the purpose of indicating positional relationships
or direction in the diagrams, and will not indicate positional
relationships or directions with respect to the actual machine when
assembled.
First Embodiment
Overall Motor Structure
[0031] FIG. 1 is a vertical section showing an electric inner
rotor-type motor 1 according to a first embodiment of the present
invention. In the diagram, the motor 1 is covered by a cylindrical
housing 11 with a small opening on the (+Z) side and a large
opening on the (-Z) side in the diagram, and by a cover plate 12,
which covers all but the center section of the opening on the (-Z)
side. Ball bearings 131, 132 are fit respectively onto the housing
11 (+Z) side opening and onto the cover plate 12 opening, and a
shaft 21 is rotatably supported by the ball bearings 131, 132. In
the explanation that follows, the (+Z) and (-Z) sides along the
motor 1 center axis J1 are respectively described as the upper and
lower sides for the sake of convenience, but there is no
requirement that the center axis J1 necessarily conform to the
direction of gravity.
[0032] A cylindrical rotor yoke 22 is attached to the shaft 21
inside the housing 11, and a multipole magnetized field magnet 23
is affixed to the outer perimeter surface of the rotor yoke 22. The
stator 3 is disposed so that the center axis J1 of the annular
stator 3 coincides with the center axis of the shaft 21.
[0033] The stator 3 comprises a plurality of teeth 31, arranged in
a radial fashion with center axis J1 as the center (that is,
extending from the inner circumferential surface of the housing 11
toward the shaft 21 (and the field magnet 23)); a plurality of
insulators 32 respectively covering the plurality of teeth 31; and
a plurality of coils 35, constructed by winding a conductor in
multiple layers along insulators 32 on each of the plurality of
teeth 31. In other words, the plurality of insulators 32 are
provided respectively between the plurality of teeth 31 and the
plurality of coils 35. Each of the teeth 31 is elongate in the
axial direction (that is, the Z direction), and the coils 35 are
formed by winding a conductor in the axially along the outer
periphery of the insulator 32. Additional details of the stator 3
will be discussed later.
[0034] On the cover plate 12 side of the stator 3, a base plate
attachment part 51 is affixed to the inner circumferential surface
of the housing 11, and a circuit board 52 is attached to the base
plate attachment part 51 so as to be positioned in between the
cover plate 12, and the field magnet 23 and stator 3. The stator 3
and the circuit board 52 are electrically connected through a
cross-over wire attached to the base plate attachment part 51.
[0035] In the motor, the shaft 21 and ball bearings 131, 132
perform the role of a bearing mechanism to rotatably support the
rotor yoke 22 relative to the housing 11, centered on the center
axis J1. The drive current supplied to the stator 3 through the
circuit board 52 is controlled so that rotational power is
generated between the stator 3 and the field magnet 23 centered on
the center axis J1, and the shaft 21 rotates together with the
rotor yoke 22.
[0036] A drive circuit for controlling the drive current supplied
to the stator 3 and a Hall sensor 521 is attached to the circuit
board 52 at the axial bottom side of the field magnet 23. The
direction of rotation and rotational position of the field magnet
23 are detected by the Hall sensor 521 to control drive current to
the stator 3. In other words, the motor 1 is what is known as a
brushless motor.
Stator Structure
[0037] FIGS. 2 and 3 are a plan view and a bottom view showing the
stator 3 prior to being furnished with the coils 35 (see FIG. 1).
In the stator 3, the plurality of teeth 31 (9 teeth in the present
embodiment) protrude radially inward from a cylindrical outside
section 30, centered on the center axis J1, and at the leading end
portions of the teeth 31 radially inward along each, teeth inner
edge portions 311 are provided on either side of the teeth 31,
circumferentially following the outside section 30 (that is, that
the width in the width orientation perpendicular to the radial
orientation centered on the center axis J1 is wider than the width
of the teeth 31). The length paralleling the center axis J1 (along
the axial orientation) of each of the teeth 31 is greater than the
teeth 31 width, and both flanks of each of the teeth 31 in the
circumferential orientation centered on the center axis J1 are
parallel to the center axis J1.
[0038] As shown in FIGS. 2 and 3, each of the teeth 31 is covered
by an insulator 32. Part of the rim surfaces of the outside section
30 on the (+Z) side and (-Z) side, and virtually the entire end
surfaces on the (+Z) and (-Z) side of each tooth inner edge portion
311 are covered by the insulators 32. The teeth 31, the outside
section 30, and the teeth inner edge portions 311 are formed by a
plurality of silicon steel plates laminated in the Z orientation
and shaped to correspond to the form of these components. The
insulators 32 are provided in order to electrically isolate the
coils 35 from each tooth 31 and its surroundings.
[0039] Each of the insulators 32, as shown in FIG. 2, is furnished
with a plurality of first guide grooves 321 in the insulator upper
end portion that covers the upper end of the tooth 31 (that is, the
end portion on the (+Z) side, which forms one end in the axial
direction). Arrayed in parallel at a pitch approximately equal to
the diameter of the conductor that forms the coils 35 (the diameter
including the coating on the conductor is preferably greater than
1.0 mm and less than 2.0 mm--in the present embodiment it is 1.5
mm), these upper guide grooves govern the wind-on position of the
conductor. In an insulator 32 focused on singly, the plurality of
guide grooves 321 is provided angled with respect to an imaginary
plane (indicated by the dot-and-dash line in FIG. 2) 300 parallel
to the center axis J1 and perpendicular to the teeth 31. The first
guide grooves 321 singly are formed in an inverse "U" that
stretches over the end surface and both flanks of the tooth 31 on
its upper side. Here, the pitch of the first guide groove 321
refers to pitch along the perpendicular to the first guide grooves
321 (indicated by arrow A1 in FIG. 2).
[0040] Each of the insulators 32 is in turn, as shown in FIG. 3,
furnished with second guide grooves 322 on its axial lower end
portion (i.e., the end portion on the (-Z) side, opposite the area
where the first guide grooves 321 (cf. FIG. 2) are formed). Arrayed
in parallel with respect to the above-described imaginary plane
300, the plurality of lower guide grooves is formed to govern the
wind-on position of the conductor. The second guide grooves 322
singly are formed in an approximate U-shape that stretches over the
end surface and both flanks of the tooth 31 on its lower side. The
pitch of the second guide groove 322--that is, the pitch along the
perpendicular to the second guide grooves 322 (normal to the
imaginary plane 300)--is equal to the pitch of the first guide
groove 321.
[0041] FIGS. 4 through 7 are enlarged views showing the tooth 31
and insulator 32 and vicinity located furthest to the (+Y) side in
FIG. 2. FIG. 4 is a plan view of the insulator 32; FIG. 5 is a
bottom view thereof; FIG. 6 is a lateral view seen from the (+X)
side heading in the (-X) direction; and FIG. 7 is an oblique view
thereof.
[0042] When forming a coil 35 (cf. FIG. 1), a conductor is wound
onto the insulator 32 along the first guide grooves 321 from the
(-X) side to the (+X) side at the upper end portion of the
insulator 32 shown in FIG. 4. The first guide grooves 321 (-X) and
(+X) sides will hereafter be referred to respectively as "start
point 3211" and "end point 3212." At the lower end portion of the
insulator 32 shown in FIG. 5, the conductor is wound onto the
insulator 32 from the (+X) side to the (-X) side along the second
guide grooves 322. The second guide groove 322 (-X) and (+X) sides
will hereafter be referred to respectively as "start point 3221"
and "end point 3222."
[0043] As shown in FIG. 4, the difference in radial distance from
the center axis J1 between the respective start points 3211 and end
points 3212 on the plurality of first guide grooves 321 is the same
as the pitch of the first guide grooves 321 and the second guide
grooves 322 (in other words, it is approximately the same as the
diameter of the conductor). It will be appreciated that this
just-described difference in radial distances is, precisely, the
difference in vertical plumb distances from a plane that includes
the center axis J1 in FIG. 2 and that is parallel to the imaginary
plane 300; it will be referred below to as the first guide groove
321 "inclination." When the inclination is such that the start
points 3211 are further away from the center axis J1 than the end
points 3212, it is deemed to be positive. The angle of inclination
of the plurality of first guide grooves 321 with respect to their
respective imaginary planes 300 (FIG. 2) is preferably greater than
5.degree. and less than 20.degree. (10.9.degree. in the present
embodiment). As shown in FIG. 5, the distances of the respective
start points 3221 and end points 3222 on the plurality of second
guide grooves 322 from the center axis J1 are equal (that is, the
inclination of the second guide groove 322 is zero).
[0044] As shown in FIGS. 4 and 5, for each of the respective
plurality of first guide grooves 321 and second guide grooves 322
in the insulator 32, the end point 3212 of a given first guide
groove 321, and the start point 3221 of a given second guide groove
322 are positioned along an axially extending straight line (that
is, along a straight line parallel to the center axis J1, which
extends in the Z orientation); and the end point 3222 of the given
second guide groove 322 and the start point 3211 of that other
first guide groove 321 that is adjacent to the given first guide
groove 321 on its (-Y) side are positioned along an axially
extending straight line.
[0045] In each of the insulators 32, in the inner edge portions
that cover the surface on the radially outward side of the tooth
inner edge portions 311, inner-edge-portion guide grooves 325 are
furnished on both sides of the tooth 31, and on the upper- and
lower-end tooth inner edge portions 311, to govern the conductor
wind-on position of the coils 35.
[0046] As shown in FIGS. 6 and 7, the insulators 32 are provided
with a first partition 323, which is a molded resin part in which
plural first guide grooves 321 are formed, and a second partition
324, which is a molded resin part in which plural second guide
grooves 322 are formed; the first partition 323 and the second
partition 324 are installed through the (+Z) and (-Z) sides of the
teeth 31 (cf. FIG. 2).
[0047] The first partitions 323 cover the upper-end surface of the
teeth 31, both flanks of the parts of the teeth 31 above the center
in the axial orientation, the rim surfaces on the upper end of the
outside section 30, areas on the radially inward surface of the
outside section 30 in the section thereof above the center, the end
surfaces on the upper side of the teeth inner edge portions 311,
and areas on the radially outward surface of the teeth inner edge
portions 311 in the section thereof above the center.
[0048] The second partition 324 is for the most part of the same
form as the first partition 323, except that its shape is the
reverse of the first partition 323, and it is provided with the
second guide grooves 322. More specifically, it covers the lower
section of the teeth 31, the underside rim surfaces of the outside
section 30 and the teeth inner edge portion 311, the radially
inward surface of the outside section 30, and areas on the radially
outward surface of the teeth inner edge portion 311 in the lower
section thereof. The insulators 32 formed by the first partitions
323 and the second partitions 324 are sandwiched between the teeth
inner edge portions 311 and the outside section 30.
[0049] FIGS. 8 and 9 are partially sectional views illustrating the
first partition 323 and the second partition 324. The area shaded
by parallel slanted lines indicates a sectional cut lying in the
imaginary plane 300 of FIGS. 2 and 3 (cf. FIG. 2). As shown in
FIGS. 8 and 9, provided on the (-Z) end of the first partition 323
(that is, the end toward the second partition 324) and on the (+Z)
end of the second partition 324 (that is, the end toward the first
partition 323), are, respectively, taper surfaces 3231a and 3241a,
provided to the outer sides of each flank on the plurality of teeth
31, roughly parallel to the YZ plane, and taper surfaces 3231b and
3241b, roughly parallel to the ZX plane. When the first partition
323 and the second partition 324 are attached to a tooth 31, the
taper surfaces 3231a and 3241a, and the taper surfaces 3231b and
3241b overlapping each other makes it possible to prevent a gap
from arising between the first partition 323 and the second
partition 324.
[0050] Of the two flanks on a tooth 31, along the outer side of the
flank on which the conductor is wound heading from the second
partition 324 end of the tooth toward the first partition 323 end,
the first partition 323 taper surface 3231a is provided on the
inner side surface of the first partition 323 (that is, the side
facing the flank of the tooth 31), and the second partition 324
taper surface 3241a is provided on the outer side surface of the
second partition 324 (that is, the side opposite that which faces
the flank of the tooth 31). Likewise, along the outer side of the
tooth 31 flank on which the conductor is wound heading from the
first partition 323 end of the tooth toward the second partition
324 end, the first partition 323 taper surface 3231a is provided on
the outer side surface of the first partition 323, and the second
partition 324 taper surface 3241a is provided on the inner side
surface of the second partition 324.
[0051] The inclination direction and angle of the taper surfaces
3231a and 3231b as seen from the first guide groove 321 side are
made to be the same as the respective inclination direction and
angle of the taper surfaces 3241a and 3241b as seen from the second
guide groove 322 side. This contributes to designing for shared use
of parts (for example, making in common part of the molding forms
and part of the design data) required for the manufacture of the
first partition 323 and second partition 324.
[0052] As shown in FIGS. 4 through 7, two protruding walls 3213 and
3214 are provided on the upper end of the first partition 323 for
preventing the conductor being layered in the (+Z) direction onto
the plurality of first guide grooves 321 from slipping out of form.
The protruding wall 3213 provided on the first guide groove 321
tooth inner edge portion 311 side (that is, the teeth 31 center
axis J1 side shown in FIG. 2) will be referred to as the "first
inner protruding wall 3213," and the protruding wall 3214 provided
on the outside section 30 side (that is, on the opposite side to
the center axis J1, sandwiching the teeth 31 and the multiple first
guide grooves 321) will be referred to as the "first outer
protruding wall 3214." The first inner protruding wall 3213 and
first outer protruding wall 3214 extend in the (+Z) direction of
the conductor layering and have a convex shape facing the teeth 31
and the plurality of first guide grooves 321. A second inner
protruding wall 3223 and a second outer protruding wall 3224 are
provided at the lower end of the second partition 324 in order to
prevent sideways slippage of the conductor layered in the (-Z)
direction on the plurality of second guide grooves 322.
[0053] FIGS. 10 through 12 illustrate a conductor having been wound
onto an insulator 32 to form a coil 35. As with FIGS. 4 through 7,
these figures focus on a single insulator. FIGS. 10 and 11 are
respectively a plan view and a bottom view showing the condition in
which a first layer 351 has been formed on the coil 35. FIG. 12 is
a plan view illustrating a situation in which a second layer 352
has been formed on the coil 35.
[0054] The circled reference numerals "1s" through "8s," and "0"
and "1e" through "7e" in FIG. 10 show the positions of the
conductor at the start point 3211 and end point 3212 in each of the
first guide grooves 321. The circled reference numeral "8e" shows
the position to which the conductor wound on the insulator 32 from
the position marked as "8s" (referred to below simply as "position
8s") is led along the (+X) side of the insulator 32. Similarly, the
circled reference numerals "1s" through "8s" and "1e" through "8e"
show the positions of the conductor at each of the second guide
groove 322 start points 3221 and end points 3222 shown in FIG. 5.
The reference numerals cited above in FIGS. 10 and 11, as well as
reference numerals "1s" through "7s" and "8," and "0" and "1e"
through "7e" in FIG. 12, indicate the conductor winding
sequence.
[0055] When a coil 35 is formed around the periphery of an
insulator 32, the conductor is first led from position 0 in FIG. 10
toward position 1s in FIG. 11, along the insulator 32 (+X) side
face in the (-Z) direction parallel to the center axis J1, and is
wound onto the insulator 32 bottom end portion from position 1s
toward position 1e in FIG. 11, along the second guide groove 322
(cf. FIG. 5). Next the conductor is led along the insulator 32 (-X)
side face in the (+Z) direction parallel to the center axis J1,
after which, by winding it from the 1s position to the 1e position
in FIG. 10 along the first guide groove 321 (cf. FIG. 4) and onto
the upper end portion of the insulator 32, the conductor completes
one revolution around the insulator 32. At the upper end portion of
the insulator 32, the conductor is led by the first guide groove
321 in a direction inclined with respect to the imaginary plane 300
(cf. FIG. 2).
[0056] Next, the conductor passes sequentially from the FIG. 10
position 1e through the FIG. 11 positions 2s, 2e, and FIG. 10
position 2s, and is wound onto the FIG. 10 position 2e. Thereafter,
by similarly winding the conductor onto the insulator 32 (and the
teeth 31), a coil 35 first layer 351 is formed. The coil 35 first
layer 351 conductor is wound 8 times around the teeth 31 (hereafter
a single turn of the conductor will be referred to as "one row"),
and is wound so that adjacent conductors in the 8 rows contact one
another with virtually no gap.
[0057] The coil 35 first layer 351 between positions 1s and 1e in
FIG. 10 contacts the first outer protruding wall 3214 (-X) side
part 3216 (referred to below as the "first layer contact part"),
and between positions 8s and 8e contacts the first inner protruding
wall 3213 (+X) side part 3215 (referred to below as the "first
layer contact part"). The first layer contact parts 3215 and 3216
are disposed along the coil 35 first layer conductor winding
direction (that is, approximately parallel to the conductor winding
direction) at the upper end portion of the insulator 32; the first
layer conductor is guided so as to follow the first contact part
3216 between positions 1s and 1e, and is guided along the first
contact part 3216 between positions 8s and 8e. The coil 35 first
layer 351, as shown in FIG. 11, also contacts the second outer
protruding wall 3224, and is guided parallel to the second outer
protruding wall 3224.
[0058] When formation of the coil 35 first layer 351 is complete,
the conductor that forms the coil 35 second layer 352 is guided
sequentially along the insulator 32 (+X) side, (-Z) side, and (-X)
side to position 1s. Thereafter, the conductor that forms the
second layer 352 is wound in a direction crossing the first layer
351 conductor at the upper end portion of the insulator 32, so that
the first layer 351 conductor and the second layer 352 conductor
cross at a crossing position 350. In other words, at the upper end
portion of the insulator 32, the first layer 351 conductor and the
second layer 352 conductor have differing inclinations. In the
present embodiment, the first layer 351 conductor has a "positive
inclination," whereas the second layer 352 has a "negative
inclination."
[0059] As shown in FIG. 12, the winding-on position of the
conductor in the innermost row of the coil 35 second layer 352
(that is, the row on the innermost side in the radial direction),
is restricted by the inner-edge-portion guide groove 325 formed on
the inner edge portion of the insulator 32 at positions 0 and 1s in
FIG. 12.
[0060] The second layer 352 conductor, by being guided to lay in
contact on two first layer 351 conductors adjoining each other on
the (+X) flank, the lower end portion, and the (-X) flank of the
insulator 32, is wound onto the insulator 32 in parallel with the
first layer 351, and positioned at position 2s. That is, along the
insulator 32 (+X) side and (-X) flanks, the second layer 352
conductor is accommodated in the hollow formed by two adjoining
conductors from among the first layer 351 conductors which are
densely wound with virtually no gaps. Thus by being guided in this
hollow, the conductor is wound onto the first layer 351 in such a
way that it is arrayed parallel to the first layer 351 and parallel
to the center axis J1. Similarly, at the lower end portion of the
insulator 32, the second layer 352 conductor is wound onto the
first layer 351 such that it is arrayed parallel to the first layer
351 conductor and parallel to the imaginary plane 300 (cf. FIG. 3).
Thereafter, the conductor is guided in a direction which crosses
the first layer 351 conductor so that it crosses the first layer
351 conductor at a crossing position 350 and heads toward position
2e; after passing through position 2e, it is then wound in parallel
to the first layer 351 conductor and reaches position 3s.
[0061] Thereafter, by winding the conductor in the same way onto
the coil 35 first layer 351, the second layer 352 is formed by the
eight rows of conductors arrayed in parallel to the first layer 351
conductor on each face of the teeth 31 (a section (for example, the
conductor on the radially innermost row) of the eight conductor
rows may cross the 351 conductor). In the coil 35 second layer 352
as well, the eight conductor rows are densely wound with virtually
no gaps so that adjacent conductors contact one another.
[0062] Between the FIG. 12 positions 1s and 1e, the coil 35 second
layer 352 contacts the first inner protruding wall 3213 (-X) side
part 3217 (the "second layer contact part" below), and between
parts 7s and 7e contacts the first outer protruding wall 3214 (+X)
side part 3218 (the "second layer contact part" below"). The second
layer contact parts 3217 and 3218 are disposed along the winding
direction of the coil 35 second layer conductor in the upper end
portion of the insulator 32 (that is, approximately parallel to the
winding direction). A second layer conductor is guided between
positions 1s and 1e along a second layer contact part 3217, and is
guided between positions 7s and 7e along a second layer contact
part 3218. The coil 35 second layer 352 also contacts the second
inner protruding wall 3223 (cf. FIG. 11), and is guided parallel to
the second inner protruding wall 3223. As is clear from FIGS. 10
and 12, the sectional shape of the first outer protruding wall 3214
takes a convex form toward the first guide groove 321 due to the
first layer contact part 3216 and the second layer contact part
3218. The sectional shape of the first inner protruding wall 3213
takes a convex form toward the first guide groove 321 due to the
first contact part 3215 and the second layer contact part 3217.
[0063] With respect to the insulator 32, the angle and surface area
formed by the first inner protruding wall 3213 first contact part
3215 (cf. FIG. 10) and the second layer contact part 3217 (cf. FIG.
12), and the angle and surface area formed by the first outer
protruding wall 3214 first layer contact part 3216 (cf. FIG. 10)
and the second layer contact part 3218 (cf. FIG. 12) are given an
appropriate size to fit the coil 35 first guide groove 321
inclination or the number of coil 35 layers, etc.
[0064] Thereafter, the conductor is similarly wound until the coil
reaches a specified number of layers, and a stator 3 is formed by
disposing the coils 35 around each of the teeth 31 and the coils
35. FIG. 13 shows a section of the coil 35 on the insulator 32
side. As shown in FIG. 13, in the present embodiment the coils 35
are formed on each of the insulators 32 using a winding machine 9
(indicated by the phantom lines in FIG. 13). The conductor is wound
around the insulator 32 across four layers within a range such that
it does not interfere with the winding machine 9. The spacing
between adjacent teeth 31 inner edge portions 311 is determined as
the size at which the winding machine 9 nozzle can be inserted. The
distance W between teeth inner edge portions 311 is preferably
greater than 3 mm and less than 4 mm (more preferably, greater than
3.2 mm and less than 3.5 mm; in the present embodiment it is 3.3
mm).
[0065] As explained above, plurality of first guide grooves 321 and
plurality of second guide grooves 322 to guide the coils 35 are
formed in the upper and lower end portions of the insulators 32;
the first guide groove 321 is disposed at an inclination of just
one pitch with respect to the imaginary plane 300 (cf. FIG. 2), and
the second guide groove 322 is disposed parallel to the imaginary
plane 300. The end point 3212 of a single first guide groove 321,
the start point 3211 of another single first guide groove 321
adjacent thereto on the (-Y) side, and the corresponding second
guide groove 322 start point 3221 and end point 3222 are all
positioned on a straight line parallel to the center axis J1 (cf.
FIG. 2).
[0066] The coil 35 second layer 352 conductor thus crosses the
first layer 351 conductor at a crossing position 350 along the
upper end of the tooth 31. Furthermore, by laying in contact on two
conductors that, among the first layer 351 conductors densely wound
with virtually no gaps onto the flanks of the teeth 31, adjoin each
other, the second layer 352 conductors are arrayed parallel to the
first layer 351 conductor. Similarly, the third and fourth layer
conductors cross the layers they contact below along the upper end
of the teeth 31 (that is, the second and third layers), and are
arrayed in parallel to the second and third layer conductors on the
flanks of the teeth 31.
[0067] As a result, crossing of conductors (for example, crossing
of the first layer 351 conductor and the second layer 352
conductor) on both faces of the teeth 31 (that is, both faces of
the insulator 32) during winding of the conductor from the second
layer 352 forward can be prevented, and the thickness of the coil
35 on both faces of the teeth 31 (the height in the X direction
from the insulator 32 face in FIG. 12) can be reduced. The coil 35
can thus be formed with a high slot-fill factor and the stator 3
can be made compact. When the coil 35 is formed using a winding
machine, contact can be prevented between the coil 35 already wound
on an insulator 32 and the winding machine which is winding a
conductor onto the adjacent 32, so that the coil 35 can be smoothly
formed.
[0068] The coil 35 second layer 352 conductor is also arrayed
parallel to the first layer 351 conductor at the bottom end of the
teeth 31 (as is true for the third and fourth layers). Crossing of
conductors at the bottom end of the teeth 31 can thus be prevented
during winding of conductors from the second layer 352 forward, and
the coil 35 thickness in the Z direction at the bottom end of the
teeth 31 can also be reduced. As a result, a further size reduction
of the stator 3 is achieved, leading to a size reduction of the
motor 1.
[0069] On the stator 3, guiding of the coil 35 by the first guide
groove 321 and the second guide groove 322 results in its
disposition at an inclination with respect to the imaginary plane
300 at the top end of the teeth 31, making it parallel to the
center axis J1 at each face of the teeth 31. It is thus possible to
achieve tighter winding of the coil 35 conductor with respect to
the teeth 31 compared to the case when the conductor is inclined
with respect to the center axis J1 on both faces of the teeth
31.
[0070] The coil 35 first layer 351 conductor is moved to the (-Y)
side by one pitch width of the first guide groove 321 and second
guide groove 322 (that is, a distance approximately equal to the
conductor diameter) with each revolution around the perimeter of
the insulator 32. As a result, the coil 35 first layer 351 can be
constructed smoothly and at a high slot-fill factor with virtually
no provision of spacing between adjacent conductors. By forming the
second layer 352 and forward by further winding of conductors on
the first layer 351 which has been thus aligned at a high slot-fill
factor, the coil 35 can be smoothly constructed and conductor
mis-winding avoided. A high coil 35 slot-fill factor can thus be
achieved without adding complexity to the stator 3 manufacturing
process.
[0071] On the stator 3 insulator 32, the first layer 351 winding is
restricted by the first guide groove 321 and the second guide
groove 322, therefore winding errors caused by the second layer 352
conductor becoming lodged between first layer 351 conductors, etc.
can be reliably prevented, and the coil 35 can be smoothly
constructed. That is, aligned winding can be achieved. Also,
winding of the conductor row on the radially innermost side among
the second layer 352 is restricted by the inner edge portion guide
groove 325. At the radially inner end section of the teeth 31,
therefore, second layer 352 conductor mis-winding caused by
mis-winding of the radially innermost conductor row of the second
layer 352 toward the radial inside direction can be prevented, and
the coil 35 can be smoothly constructed.
[0072] At the insulator 32, the winding position at the center axis
J1 side and the outside section 30 side of the plurality of layers
of conductors which cross at the first guide groove 321 is guided
by the first inner protruding wall 3213 and first outer protruding
wall 3214, which are mutually convex facing the plurality of first
guide grooves 321. Therefore the coil 35 can be smoothly
constructed even at the end section of the plurality of first guide
grooves 321 center axis J1 side and the outside section 30 side.
The first inner protruding wall 3213 and the first outer protruding
wall 3214 restrict the position and direction of winding of the
first layer 351 and second layer 352 conductors by use of the first
layer contact parts 3215 and 3216 and the second layer contact
parts 3217 and 3218, thus achieving an aligned winding of the first
layer 351 and the second layer 352, so that aligned winding of the
coil 35 can be more easily realized.
[0073] On the insulator 32, the taper surfaces 3231a and 3231b are
disposed on the second partition 324 side of the first partition
323, the taper surfaces 3241a and 3241b are disposed on the first
partition 323 side of the second partition 324, and the taper
surfaces 3231a, 3231b overlap with the taper surfaces 3241a, 3241b
when winding onto the first partition 323 and second partition 324
teeth 31, thus enabling the prevention of gap formation between the
first partition 323 and the second partition 324, while simplifying
the assembly of the first partition 323 and the second partition
324.
[0074] Furthermore, on the insulator 32, of the two flanks on a
tooth 31, along the flank on which the conductor is wound from the
second partition 324 section to the first partition 323 section,
the taper surfaces 3231a and 3241a are provided on the inner side
surface of the first partition 323 and the outer side surface of
the second partition 324. In turn, along the flank on which the
conductor is wound heading from the first partition 323 section to
the second partition 324 section the taper surfaces 3231a and 3241a
are provided on the outer side surface of the first partition 323
and the inner side surface of the second partition 324. In other
words, for the first partition 323 and the second partition 324, at
the first guide groove 321 and second guide groove 322 the taper
surfaces 3231a, 3231b are formed on the outside of the face on the
start point 3211 and 3221-flanks, and the taper surfaces 3231a,
3231b are formed on the inside of the face on the end point 3212
and 3222-flanks. Therefore on the face at the side on which the
conductor is wound from the top toward the bottom (that is, the
face on the side of the first guide groove 321 end point 3212), the
first partition 323 is positioned on the outside of the second
partition 324 in the area of the joint between the first partition
323 and the second partition 324. On the face at the side on which
the conductor is wound from the bottom toward the top (that is, the
face on the side of the second guide groove 322 end point 3222),
the second partition 324 is positioned on the outside of the first
partition 323 in the area of the joint between the first partition
323 and the second partition 324. As a result, catching of the
conductor (and the winding machine 9 nozzle) on the joint between
the first partition 323 and the second partition 324 during winding
of the conductor on the teeth 31 can be prevented, and the coil 35
can be smoothly constructed.
Second Embodiment
[0075] FIGS. 14 and 15 are respectively a plan view and a bottom
view showing the region of an insulator 32 in a motor stator
according to a second embodiment of the present invention. In a
motor according to the second embodiment, a plurality of insulators
32a is disposed in place of the plurality of insulators 32 shown in
FIG. 1. Other structures are the same as in FIG. 1, and the same
reference numerals are used in the explanation below.
[0076] In a motor according to a second embodiment, as with the
motor 1 according to the first embodiment, insulators 32a are
provided with a first partition 323 and a second partition 324
respectively attached on the (+Z) side and the (-Z) side of the
teeth 31 (cf. FIG. 6). A plurality of first guide grooves 321 is
formed at the upper end portion of the first partition 323, and a
plurality of second guide grooves 322 is formed at the lower end
portion of the second partition 324.
[0077] As shown in FIGS. 14 and 15, the difference in radial
distance (that is, the inclination of the first guide groove 321)
from the center axis J1 (cf. FIG. 2) of the plurality of first
guide groove 321 respective start points 3211 and end points 3212,
and the difference in radial distance from the center axis J1 of
the plurality of second guide groove 322 respective start points
3221 and end points 3222 (that is, the inclination of the second
guide groove 322) is equal to one half the pitch of the first guide
groove 321 and the second guide groove 322. The outer protruding
wall and inner protruding wall corresponding to the first partition
323 outside section 30 and teeth inner edge portion 311 extend in
the (+Z) direction and have a sectional shape which is convex
toward the first guide groove 321, as in the first embodiment. The
insulator 32a is formed so as also to be convex toward the second
guide groove 322 for the second partition 324 outer protruding wall
and inner protruding wall.
[0078] Also, similar to the insulator 32 shown in FIGS. 4 and 5,
for the plurality of first guide grooves 321 and second guide
grooves 322, the respective single first guide groove 321 end point
3212 and single second guide groove 322 start point 3221 are
positioned on a straight line extending in the Z direction (that
is, on a straight line parallel to the center axis J1). The guide
groove 322 end point 3222 and the start point 3211 of another first
guide groove 321 adjacent to the first guide groove 321 on the (-Y)
side are positioned on a straight line extending in the Z
direction. As with the motor 1 according to the first embodiment,
in the motor according to a second embodiment a coil 35 is
constructed by winding plurality of conductor layers on each
insulator 32a to form a stator 3.
[0079] In the motor stator according to the second embodiment, the
shape of the insulator 32a in the region of the first guide groove
321 and the second guide groove 322 can be made the same by making
the inclination of the first guide groove 321 and the second guide
groove 322 equal. As a result, the same parts can be used to
manufacture the insulator 32a first partition 323 and the second
partition 324.
[0080] In the stator according to the second embodiment, because
the coil 35 conductor is guided by the first guide groove 321 and
the second guide groove 322, the conductor during winding of the
second layer 352 conductor crosses the first layer 351 conductor at
the upper and lower ends of the teeth 31 and is wound onto the
teeth 31. Along the flanks of the teeth 31, the first layer 351
conductor and the second layer 352 conductor are aligned so as to
be parallel to one another. By this means, as with the first
embodiment, crossing of conductors on the two faces of the teeth 31
is prevented when winding the second layer 352 and subsequent
conductor layers, and the thickness of the coil 35 on both faces of
the teeth 31 can be reduced. By making the coil 35 conductor
parallel to the center axis J1 on each face of the teeth 31, the
conductor can be wound more densely with respect to the teeth
31.
[0081] Again, as with the first embodiment, by moving the coil 35
first layer 351 conductor by one pitch only to the (-Y) side for
each revolution around the periphery of the insulator 32a, there
are virtually no gaps created between adjoining conductors, and the
coil 35 can be smoothly constructed with a high slot-fill factor.
Because the conductor winding is restricted by the first guide
groove 321 and the second guide groove 322 in the insulator 32a,
conductor mis-winding can be reliably prevented and the coil 35
smoothly constructed.
Third Embodiment
[0082] FIGS. 16 and 17 are partially sectional views showing one
insulator's first partition 323a and second partition 324a in a
motor stator according to a third embodiment of the present
invention. The ""shaded area indicated by parallel slanted lines,
as in FIGS. 8 and 9, is a section through an imaginary plane 300
(cf. FIG. 2) which is parallel to the center axis J1 and
perpendicular to the teeth 31. Each of the insulators in the motor
according to the third embodiment is the same as those in FIG. 1
with the exception that the sectional shape of the end section
differs slightly in the direction parallel to the center axis J1.
The same reference numerals are used in the explanation below.
[0083] As shown in FIG. 16, in the first partition 323a, a first
crown section 3232, which is the most (+Z)-ward, distal edge of the
end portion on the partition side where the first guide grooves 321
are formed, is positioned closer to the end point side than the
start point side of the conductor winding (that is, closer to the
first guide groove 321 end point 3212 than the start point 3211).
As shown in the FIG. 18 expanded view, the cross-sectional form of
the end portion on the (+Z) side of the first partition 323a has a
larger radius of curvature R1 on the (+X) side (that is, on the
first guide groove 321 end point 3212 side) than the radius of
curvature R1 on the (-X) side (that is, on the first guide groove
321 start point 3211 side). In the present embodiment, the radius
of curvature R1 is set at approximately 3 mm, and the radius of
curvature R2 is approximately 4.1 mm.
[0084] As shown in FIG. 17, in the second partition 324a as well, a
second crown section 3242, which is the most (-Z)-ward, distal edge
of the end portion on the partition side where the second guide
grooves 322 are formed, is positioned closer to the start point
side than the end point side of the conductor winding (that is,
closer to the start point 3221 than the end point 3222 of the
plurality of second guide grooves 322). In the cross-sectional form
of the second partition 324a, the radius of curvature on the end
point 3222 side is greater than that on the start point 3221
side.
[0085] As explained above, in the motor insulator 32 according to
the third embodiment, the bending of parts from the crown section
of the first guide groove 321 and the second guide groove 322 up to
the winding end point is kept gradual, without changing the width
of the first guide groove 321 and the second guide groove 322 in
the X direction. This makes it possible to stop the conductor from
separating from the insulator 32 in the region around the first
guide groove 321 end point 3212 and in the region of the second
guide groove 322 end point 3222 and, by preventing mis-winding of
the conductor, to smoothly construct the coil 35. The thickness of
the coil 35 on both faces of the insulator 32 can also be reduced.
This structure which makes it possible to keep separation of the
conductor from the insulator 32 under control is particularly
suited to a stator in which the axial length of the teeth 31 is
longer than the width thereof, and in which the radius of curvature
at the top and lower end portions of the insulator 32 is relatively
small.
[0086] It will be appreciated that it is acceptable for the end
section at which the radius of curvature varies to be only one of
the end sections from the first guide groove 321 side and the
second guide groove 322 side. "Radius of curvature" at the start
point and the end point sides refers to an approximate radius of
curvature. For example, it can be interpreted as an average radius
of curvature, and can also be interpreted as a minimum radius of
curvature on the start point and end point sides.
[0087] While several preferred embodiments of the present invention
have been explained, the present invention is not limited to the
foregoing embodiments, and may be variously modified.
[0088] For example, for the stator 3 insulator, the first guide
groove 321 can be set to be parallel to the imaginary plane 300,
and the second guide groove 322 can be disposed so as to be
inclined by just one pitch with respect to the imaginary plane 300,
so that the coil 35 is formed such that conductors cross only at
the bottom end of the teeth 31.
[0089] In the stator 3, a high slot-fill factor coil 35 can be
constructed by winding the coil 35 conductor in such a way that it
is parallel to the center axis J1 on each face of the teeth 31 and
moves by just one pitch unit for each revolution around the
insulator. Thus from the standpoint of building the coil 35 at a
high slot-fill factor, the total respective inclinations of, for
example, the first guide groove 321 and the second guide groove 322
do not have to be equal to the pitch. For example, the respective
inclinations of the first guide groove 321 and the second guide
groove 322 could be set at a 0.7.times. and 0.3.times. the
pitch.
[0090] From the standpoint of improving the coil 35 slot-fill
factor, it is preferable that the inclination of the first guide
groove 321 and the second guide groove 322 be greater than 0, and
that it be less than the pitch of the first guide groove 321 and
the second guide groove 322. In other words, it is preferable to
make the difference in distance from the center axis J1 to the
first guide groove 321 start point 3211 and end point 3212, and the
difference in distance from the center axis J1 to the second guide
groove 322 start point 3221 and end point 3222 be less than the
pitch of the first guide groove 321 and the second guide groove
322.
[0091] For the stator 3, speaking only from the standpoint of
reducing the coil 35 thickness at both faces of the teeth 31, it is
sufficient for the various coil 35 layers to be mutually aligned in
parallel and to be wound along approximately the center axis J1;
they may be slightly inclined with respect to the center axis J1.
Therefore when the coil 35 is formed so that the conductors cross
only at the top end (and/or the bottom end) of the teeth 31, then
for example the first guide groove 321 and the second guide groove
322 may be disposed in parallel to the imaginary plane 300. In that
case, the coil 35 conductor is disposed so as to be slightly
inclined with respect to the center axis J1 at both sides or at one
side of the teeth 31. For a conductor inclination at both faces of
the teeth 31, that inclination is equal to one pitch unit of the
first guide groove 321 and second guide groove 322.
[0092] A reduction in the coil 35 thickness can be achieved on both
faces of the teeth 31 even in cases where, for example, one or two
rows of a conductor among the eight conductor rows of the coil 35
second layer 352 cross the first layer 351 conductor on the various
faces of the teeth 31. Thus, by virtue of the majority of conductor
rows in each layer being mutually aligned in parallel with the
conductors in adjacent layers on each face of the teeth 31, the
thickness of the coil 35 can be reduced on both faces of the teeth
31, even in cases in which some conductors cross on the face of
teeth 31 with the conductors of an adjacent layer.
[0093] A guide groove which joins the first guide groove 321 start
point 3211 and the second guide groove 322 end point 3222, and a
guide groove which joins the first guide groove 321 end point 3212
and the second guide groove 322 start point 3221 may be constructed
on a face of the insulator. The conductor which forms the coil 35
first layer 351 may also be wound from the center axis J1 side to
the outside section 30 side with respect to the insulator.
[0094] In cases where it is possible to prevent mis-winding of the
conductor and smoothly construct the coil 35 by slackening the
conductor winding to some degree with respect to the teeth 31 so as
to cause the conductors to cross only at the top end (and/or bottom
end) of the teeth 31, the insulator first guide groove 321 and/or
second guide groove 322 may be omitted. In cases where mis-winding
of the conductor row on the radially innermost side of the second
layer 352 is reliably prevented by contact, etc. with the first
inner protruding wall 3213, the insulator 32 inner edge portion
guide groove 325 may be omitted.
[0095] Insulators attached to plurality of (nine in the present
preferred embodiment) teeth 31 may be comprised of nine first
partitions 323 connected or integrally formed in an annular shape,
and nine second partitions 324 connected or integrally formed in an
annular shape. The insulator is not limited to being formed by
attachment of a resin-molded first partition 323 and second
partition 324 to the teeth 31 and could, for example, be formed by
molding a thermoplastic resin for the teeth 31. In such cases, the
plurality of teeth 31 could be said to be covered by a single
insulator. With such an insulator, plurality of first guide grooves
321 are formed on the upper end portions which cover the respective
top ends of the plurality of teeth 31 (that is, the respective
upper end portions of the plurality of parts which cover the
respective plurality of teeth 31), and plurality of second guide
grooves 322 are formed at the bottom ends which cover the
respective bottom ends of the plurality of teeth 31.
[0096] The stator 3 may be a segmented type in which laminar
components including the individual teeth 31 are appropriately
situated--for example, in which in between adjoining teeth 31 the
outside section 30 is discontinuous.
[0097] Motors provided with the stator 3 are not limited to inner
rotor types; they may also be of the outer rotor type.
* * * * *