U.S. patent application number 09/769271 was filed with the patent office on 2002-10-31 for alternator.
Invention is credited to Adachi, Katsumi, Asao, Yoshihito, Harada, Yoshihiro, Oohashi, Atsushi.
Application Number | 20020158539 09/769271 |
Document ID | / |
Family ID | 18716380 |
Filed Date | 2002-10-31 |
United States Patent
Application |
20020158539 |
Kind Code |
A1 |
Oohashi, Atsushi ; et
al. |
October 31, 2002 |
ALTERNATOR
Abstract
An alternator includes a stator winding in which a plurality of
lead wires extending from winding phase groups for each phase are
connected in an alternating connection via a terminal assembly for
three-phase connection, and the terminal assembly for three-phase
connection is disposed at a side of a rotor to which a fan unit is
fixed and opposite to the rotor with respect to an end face of the
fan unit in the axial direction of the rotor, the terminal assembly
opposing the top of a coil-end group of the stator winding.
Inventors: |
Oohashi, Atsushi; (Tokyo,
JP) ; Harada, Yoshihiro; (Tokyo, JP) ; Asao,
Yoshihito; (Tokyo, JP) ; Adachi, Katsumi;
(Tokyo, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037
US
|
Family ID: |
18716380 |
Appl. No.: |
09/769271 |
Filed: |
January 26, 2001 |
Current U.S.
Class: |
310/207 ;
310/180; 310/201; 310/257; 310/68D |
Current CPC
Class: |
H02K 11/05 20160101;
H02K 3/28 20130101; H02K 3/50 20130101; H02K 11/049 20160101 |
Class at
Publication: |
310/207 ;
310/180; 310/201; 310/257; 310/68.00D |
International
Class: |
H02K 003/28; H02K
003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2000 |
JP |
2000-222077 |
Claims
What is claimed is:
1. An alternator comprising: a stator including a cylindrical
stator core provided with a plurality of slots extending in an
axial direction of said stator, said plurality of slots being
disposed in parallel to each other along the circumference of said
stator, and a stator winding mounted in said plurality of slots of
said cylindrical stator core, said stator winding including n-sets
(n represents a natural number) of a three-phase alternating
winding, each set of said three-phase alternating winding being
constructed by connecting winding phase groups for three phases
offset from each other by an electrical angle of 120 degrees into
an alternating connection; a rotor enclosed by said cylindrical
stator core; a fan unit mounted on said rotor; and a rectifier,
wherein said stator winding comprises first wave-shaped windings
and second wave-shaped windings, said first wave-shaped windings
being composed of 3n first winding sub-portions each having one
turn constructed by winding in a wave-shape a strand of wire so as
to alternately occupy an inner layer and an outer layer in a
slot-depth direction within said slots at every 3.multidot.nth
slot, said first winding sub-portions being disposed at a pitch of
one slot from each other, and said second wave-shaped windings
being composed of 3n second winding sub-portions each having one
turn constructed by winding in a wave-shape said strand of wire so
as to alternately occupy the inner layer and the outer layer in the
slot-depth direction within said slots at every 3.multidot.nth slot
and so as to be inversely wound and offset by an electrical angle
of 180 degrees relative to said first winding sub-portions, said
second winding sub-portions being disposed at a pitch of one slot
from each other, whereby m-pairs (m represents a natural number) of
said first wave-shaped windings and said second wave-shaped
windings are disposed so as to arrange alternately and in a row
in-slot-received portions of said first winding sub-portions and
in-slot-received portions of said second winding sub-portions in
the slot-depth direction within each of said slots; wherein each
set of said three-phase alternating winding is formed by connecting
a plurality of lead wires to each other extending from said first
winding sub-portions and said second winding sub-portions via a
conductive relay member, and connecting into the alternating
connection said three winding phase groups each composed of said
first winding sub-portions and said second winding sub-portions
which are mounted in every 3.multidot.nth slot; and wherein said
conductive relay member opposes the top of a coil-end group of said
stator winding across a gap therebetween.
2. The alternator according to claim 1, wherein said fan unit is
fixed to said rotor at least one end thereof, said rectifier is
disposed at a side of said rotor to which said fan unit is fixed,
said conductive relay member is disposed at the side of said rotor
to which said fan unit is fixed and is disposed opposite to said
rotor with respect to an end face of said fan unit in the axial
direction of said rotor, said plurality of lead wires serve as
alternating-output lead wires for said three-phase alternating
winding, said conductive relay member serves as conductive
alternating-output-relay members having
alternating-current-output-connec- tion terminals extending
inwardly in the radial direction of said rotor, and said
alternating-output lead wires are connected to said conductive
alternating-output-relay members and are connected to said
rectifier via said alternating-current-output-connection
terminals.
3. The alternator according to claim 1, wherein said plurality of
lead wires serve as neutral-point-connection lead wires for said
winding phase group, said conductive relay member serves as a
conductive neutral-point-relay member, and said
neutral-point-connection lead wire for each phase is integrally
connected to said conductive neutral-point-relay member.
4. The alternator according to claim 3, wherein said conductive
neutral-point-relay member includes a neutral-point-connection
terminal extending inwardly in the radial direction of said stator,
and said neutral-point-connection terminal is connected to said
rectifier.
5. The alternator according to claim 1, wherein said plurality of
lead wires serve as bridge-connection lead wires between said first
winding sub-portions and said second winding sub-portions, said
conductive relay member serves as conductive
bridge-connection-relay members, and said bridge-connection lead
wires are connected to said conductive bridge-connection-relay
members, whereby said first winding sub-portions and said second
winding sub-portions are bridge-connected.
6. The alternator according to claim 1, wherein said plurality of
lead wires extend in parallel to each other from said first winding
sub-portions and said second winding sub-portions in the axial
direction, and are connected to said conductive relay member
substantially at the same predetermined level as each other from an
end face of said stator core.
7. The alternator according to claim 1, wherein said conductive
relay member and an insulative resin member are formed integrally
with each other.
8. The alternator according to claim 1, wherein said stator is
formed so that the coil-end group of said stator winding does not
overlap said fan unit in the radial direction.
9. The alternator according to claim 1, wherein the size of said
conductive relay member in a radial direction of said stator is not
greater than the size of the coil-end group of said stator winding
in the radial direction of said stator.
10. The alternator according to claim 1, wherein said strand of
wire is a continuous conductive wire, and said first winding
sub-portion and said second winding sub-portion form each of said
first wave-shaped windings wound in one turn and each of said
second wave-shaped windings wound in one turn, respectively.
11. The alternator according to claim 10, wherein each pair of said
first wave-shaped windings and said second wave-shaped windings is
formed with a winding assembly composed of a plurality of said
first winding sub-portions and a plurality of said second winding
sub-portions.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to alternators driven by
internal combustion engines. In particular, the present invention
relates to a connection structure of a stator winding of an
alternator to be mounted on an automotive vehicle, such as an
automobile or a truck.
[0003] The entire content of the basic Japanese Patent Application
from which the priority under the Convention is claimed in this
application is hereby incorporated by reference into this
application.
[0004] 2. Description of the Related Art
[0005] In recent years, reduced sizes, increased outputs, and
improved quality have been increasingly required of alternators. In
order to obtain an increased output from an alternator reduced in
size, it is important to distribute magnetic loading and electrical
loading in a most appropriate manner and at a highest possible
concentration within a limited volume.
[0006] The outputs of automotive alternators must be increased
because of increasing vehicle loads while engine compartments
become smaller, thereby reducing spaces for mounting the
alternators. There are requirements to reduce the noise of the
automotive alternators which operate all the time for supplying
electricity, the noise becoming relatively large with respect to
the engine noise which has been reduced in response to the
requirements to reduce the noise generated toward the outside and
the inside of the vehicle compartments. The automotive alternators,
which operate all the time, are required to have a very high heat
resistance because of their severe operating thermal condition in
which the alternators are heated by a high Joule heat generated by
the output current.
[0007] In order to reduce the size and increase the output of an
alternator, the resistance of a stator winding must be reduced, the
space factor of electrical conductors in magnetic circuits of the
stator must be increased, and the bridge portions (bridge portions
outside a stator core are called coil ends) of the stator winding
must be set in order and be concentrated. Furthermore, the
requirements for reduced noise and heat resistance, and the like
must be complied with.
[0008] A structure for reducing the resistance of windings (heat
loss), improving the space factor of electrical conductors, and
lining up and concentrating coil ends was proposed disclosed in,
for example, Japanese Patent No. 2927288, in which conductor
segments formed substantially in a U-shape with short conductive
wires having large cross-sections are used as strands of wire of
the stator winding.
[0009] In an alternator of this type, the number of slots per pole
and per phase tends to increase, that is, the alternator tends to
have a plurality of sets of a three-phase alternating winding in
order to comply with the requirements for reduced electrical and
magnetic noise and high quality electricity supply, whereby the
number of lead wires for the three-phase alternating winding is
increased. When forming the three-phase alternating winding, a
wiring process is necessary in which lead wires extending from the
windings are drawn and are folded, and are connected. The laborious
work in the wiring process is required to be alleviated. However,
in the above Japanese Patent No. 2927288, the reduction of the load
in the wiring process was not considered.
[0010] Therefore, the applicant of the present invention proposed a
connection structure of lead wires of a stator winding in Japanese
Patent Application No. 2000-011704 (a privately known but
unpublished), for reducing load in a wiring process by alleviating
the work for drawing and folding lead wires during a connection
process of the stator winding.
[0011] FIG. 11 is a sectional view of a known automotive alternator
proposed in Japanese Patent Application No. 2000-011704. FIG. 12 is
a perspective view of a stator used in the known automotive
alternator. FIG. 13 is a rear-end view explaining connections in
one phase of a stator winding of the known automotive alternator.
FIG. 14 is a perspective view of a terminal assembly for
three-phase alternating connections in the stator of the known
automotive. FIG. 15 is an illustration explaining a method of
connection between a rectifier and the stator winding of the known
automotive alternator. FIG. 16 is a block diagram of a circuit used
in the known automotive alternator.
[0012] The automotive alternator shown in FIG. 11 includes a
Lundell-type rotor 7 rotatably supported by a shaft 6 in a case 3
formed with aluminum front bracket 1 and rear bracket 2. A stator 8
is fixed to the inner wall of the case 3 so as to cover the rotor 7
at the periphery of the rotor 7.
[0013] The shaft 6 is rotatably supported by the front bracket 1
and the rear bracket 2. A pulley 4 is fixed to the shaft 6 at one
end thereof, for transmitting the rotational torque of an engine to
the shaft 6 via a belt (not shown).
[0014] Slip rings 9 for feeding current are fixed to the other end
of the shaft 6. A pair of brushes 10 are received in a brush holder
11 disposed in the case 3. The pair of brushes 10 are held in
contact with the slip rings 9 so as to slide thereon. A regulator
18 for regulating alternating voltage generated at the stator 8 is
connected to a heat sink 17 coupled with the brush holder 11.
Rectifiers 12 for rectifying alternating current generated at the
stator 8 into direct current are mounted in the case 3, the
rectifiers 12 being electrically connected to the stator 8.
[0015] The rotor 7 includes a rotor coil 13 for generating magnetic
flux on passage of electric current, and a pair of pole cores 20
and 21 so as to cover the rotor coil 13, magnetic poles being
formed in the pole cores 20 and 21 by the magnetic flux generated
in the rotor coil 13. The pair of iron pole cores 20 and 21 include
eight claw-shaped magnetic poles 22 and eight claw-shaped magnetic
poles 23 around the peripheries of the pole cores 20 and 21,
respectively, protruding therefrom and disposed at the same angular
distance from each other in the circumferential directions of the
respective pole cores 20 and 21. The pair of pole cores 20 and 21
are fastened to the shaft 6 facing each other such that the
claw-shaped magnetic poles 22 and 23 intermesh. A fan unit 5 is
fixed to the rotor 7 at each axial end thereof.
[0016] Intake openings 1a and 2a are formed in the front bracket 1
and the rear bracket 2, respectively, at each axial end face.
Discharge openings 1b and two outlets 2b are formed in two outer
circumferential shoulder portions of the front bracket 1 and the
rear bracket 2, opposite the radial outside of the front-end and
rear-end coil-end groups 16f and 16r of the stator winding 16.
[0017] In FIG. 12, the stator 8 includes a cylindrical stator core
15, made of laminated iron, provided with a plurality of slots 15a
formed extending in the axial direction at a predetermined pitch in
the circumferential direction, the stator winding 16 wound onto the
stator core 15, and insulators 19 disposed in the slots 15a for
electrically insulating the stator winding 16 from the stator core
15. The stator winding 16 include twenty-four winding sub-portions
in each of which one strand of wire 30 is bent back outside the
slots 15a at both end surfaces of the stator core 15 and wound in a
wave-shape so as to alternately occupy an inner layer and an outer
layer in a slot depth direction within slots 15a at every sixth
slot (equals a pitch of the magnetic poles). The stator core 15 is
provided with ninety-six slots 15a at the same distance from each
other so as to receive two sets of the three-phase alternating
winding corresponding to the number of the magnetic poles which is
16. Along copper wire having a rectangular cross-section and coated
with an insulating film, for example, is used as the strand of
wire.
[0018] The winding configuration of a winding phase group 161 for a
phase a is described below with reference to FIG. 13.
[0019] The winding phase group 161 for the phase a include first to
fourth winding sub-portions 31 to 34, each winding sub-portion
being formed with one strand of wire 30. The first winding
sub-portion 31 is formed in a manner such that one strand of wire
30 is wound in a wave-shape into every sixth slot from slot number
1 to 91 so as to alternately occupy a first position from the inner
circumferential side (hereinafter, referred to as a first address)
and a second position from the inner circumferential side
(hereinafter, referred to as a second address) inside the slots
15a, and the both ends of the strand of wire 30 are connected to
each other, thereby forming the wave-shaped winding sub-portion in
one turn. The second winding sub-portion 32 is formed in a manner
such that one strand of wire 30 is wound in a wave-shape into every
sixth slot from slot number 1 to 91 so as to alternately occupy the
second address and the first address inside the slots 15a, and the
both ends of the strand of wire 30 are connected to each other,
thereby forming the wave-shaped winding sub-portion in one turn.
The third winding sub-portion 33 is formed in a manner such that
one strand of wire 30 is wound in a wave-shape into every sixth
slot from slot number 1 to 91 so as to alternately occupy a third
position from the inner circumferential side (hereinafter, referred
to as a third address) and a fourth position from the inner
circumferential side (hereinafter, referred to as a fourth address)
inside the slots 15a, and the both ends of the strand of wire 30
are connected to each other, thereby forming the wave-shaped
winding sub-portion in one turn. The fourth winding sub-portion 34
is formed in a manner such that one strand of wire 30 is wound in a
wave-shape into every sixth slot from slot number 1 to 91 so as to
alternately occupy the fourth address and the third address inside
the slots 15a, and the both ends of the strand of wire 30 are
connected to each other, thereby forming the wave-shaped winding
sub-portion in one turn. The strands of wire 30 are arranged to
line up in a row of four strands within each slot 15a with the
longitudinal direction of their rectangular cross-sections aligned
in a radial direction.
[0020] Portions of the strands of wire 30 of the first and third
winding sub-portions 31 and 33 extending from slot numbers 61 and
67 at an end surface of the stator core 15 are cut, respectively,
and portions of the strands of wire 30 of the second and fourth
winding sub-portions 32 and 34 extending from slot numbers 55 and
61 at the end surface of the stator core 15 are cut, respectively.
Then, a cut end 31b of the first winding sub-portions 31 and a cut
end 33a of the third winding sub-portion 33 are connected, a cut
end 32b of the second winding sub-portions 32 and a cut end 34a of
the fourth winding sub-portion 34 are connected, and a cut end 31a
of the first winding sub-portions 31 and a cut end 32a of the
second winding sub-portion 32 are connected. Thus, the winding
phase group 161 in four turns for the phase a is formed with the
first to fourth winding sub-portions 31 to 34 connected to each
other in series.
[0021] Cut ends 33b and 34b of the third and fourth winding
sub-portions 33 and 34, respectively, serve as an
alternating-current-output lead wire Oa and a neutral-point lead
wire Na for the phase a, respectively.
[0022] In the same manner, other five sets of four winding
sub-portions are disposed in every sixth slot 15a. Thus, the
winding phase groups 161 are formed for six phases, each set of
four winding sub-portions being offset from the other by one
slot.
[0023] In FIG. 12, two sets of a three-phase alternating winding
constituting the stator winding 16 include twenty-four winding
sub-portions connected in an alternating-current connection by
using two three-phase-connection terminal-assemblies 100. In FIG.
14, each three-phase-connection terminal-assembly 100 includes a
conductive neutral-point-connection member 101, three conductive
bridge-connection members 102, and an insulative resin member 103
formed integrally with each other. The conductive
neutral-point-connection member 101 is formed by bending a metallic
bar made of copper or the like having a rectangular cross-section,
and includes three connection tabs 101a and one neutral-point lead
wire 101b. Each conductive bridge-connection member 102 is formed
by bending a metallic bar made of copper or the like in a U-shape
having a rectangular cross-section, and includes connection tabs
102a at the both ends thereof.
[0024] Two three-phase-connection terminal-assemblies 100 are
disposed on the coil-end group 16r of the stator winding 16 in
which the cut ends of the winding sub-portions for each phase are
connected in a manner such that the cut ends 31b and 33a of the
first and third winding sub-portions 31 and 33, respectively, are
connected to each other by arc welding or the like, and the cut
ends 32b and 34a of the second and fourth winding sub-portions 32
and 34, respectively, are connected to each other by arc welding or
the like. The cut ends 31a and 32a of the first and second winding
sub-portions 31 and 32 for each phase are led around, are folded,
and are connected to the connection tabs 102a of each conductive
bridge-connection members 102 by arc welding or the like. Thus, the
winding phase groups 161 for the phase a, phase b, phase c, phase
a', phase b', and phase c' are formed, the winding phase group 161
for each phase being configured with the first to fourth winding
sub-portions 31 to 34. The cut end 34b of the fourth winding
sub-portion 34 for each phase is led, is folded, and is connected
to one of the connection tabs 101a of each conductive
neutral-point-connection member 101 by arc welding or the like.
Thus, a three-phase alternating winding is formed by connecting the
winding phase groups 161 for the phases a, b and c in the
alternating connection, and another three-phase alternating winding
is formed by connecting the winding phase groups 161 for the phases
a', b' and c' in the alternating connection. The cut ends 31a and
32a of the first and second winding sub-portions 31 and 32,
respectively, function as the bridge-connection lead wires.
[0025] In the stator 8 thus configured, as shown in FIG. 12, two
three-phase-connection terminal-assemblies 100 are disposed in the
vicinity of the coil-end group 16r of the stator winding 16 wound
onto the stator core 15. The alternating-current-output lead wires
Oa, Ob, Oc, Oa', Ob', and Oc', and the neutral-point lead wires
Nabc and Na'b'c', which are the neutral-point lead wires 101b, of
the two three-phase alternating windings of the stator winding 16
extend from the coil-end group 16r of the stator winding 16 in the
axial direction.
[0026] In FIG. 15, a metallic connector 104 is fixed to the
alternating-current-output lead wire Oa at the end thereof, is bent
in the radial direction, and is connected to the rectifier 12.
Other metallic connectors 104 are fixed to the
alternating-current-output lead wires Ob, Oc, Oa', Ob', and Oc' and
the neutral-point-connection lead wires Nabc and Na'b'c' at the
ends thereof, are bent in the radial directions, and are connected
to the rectifier 12. Thus, as shown in FIG. 16, three phases each
of the winding phase groups 161 are connected into the alternating
connection to form the two sets of the three-phase alternating
winding 160, and each of the three-phase alternating windings 160
is connected to its own rectifier 12. The direct current outputs of
each rectifier 12 are combined by being connected in parallel. The
neutral points of the three-phase alternating windings 160 are
connected to direct current output terminals of the respective
rectifier 12 via diodes 29.
[0027] In the known automotive alternator described above, the
three-phase-connection terminal-assemblies 100 are disposed in the
vicinity of the coil-end group 16r of the stator winding 16 and in
a path of cooling air of the fan unit 5 between the coil-end group
16r and the rectifier 12, thereby increasing the wind resistance
against the cooling air, whereby decreasing the volume of cooling
air. Therefore, the rectifier 12 and the stator winding 16 cannot
be cooled effectively, thereby increasing the temperature of the
rectifier 12 and the stator winding 16. With the heat-up of the
stator winding 16, the output thereof decreases. When the volume of
cooling air is the same, wind noise increases by the
three-phase-connection terminal-assemblies 100 which are disposed
between the coil-end group 16r and the rectifier 12.
[0028] In the known alternator, the alternating-current-output lead
wires Oa, Ob, Oc, Oa', Ob', and Oc' and the
neutral-point-connection lead wires Nabc and Na'b'c' of the
three-phase alternating windings 160 are directly connected to the
rectifier 12. Therefore, it is necessary to fix the metallic
connectors 104 to the above alternating-current-output lead wires
and the neutral-point-connection lead wires at the ends thereof, to
bend the lead wires in the radial direction, and to couple the
metallic connectors 104 with the rectifier 12, thereby increasing
load in the connecting process.
[0029] The three-phase-connection terminal-assemblies 100, disposed
close to the coil-end group 16r, reduce the space required for
connection of the neutral-point lead wires and the
bridge-connection lead wires with the conductive
neutral-point-connection members 101 and the conductive
bridge-connection members 102, respectively, thereby deteriorating
the operation efficiency in the connecting process. The connecting
operation, in which the neutral-point lead wires and the
bridge-connection lead wires are led around, are folded, and are
connected to the conductive neutral-point-connection members 101
and the conductive bridge-connection members 102, respectively,
also deteriorates the efficiency in the connecting process.
SUMMARY OF THE INVENTION
[0030] Accordingly, it is an object of the present invention to
provide a high-output alternator reduced in size in which wind
resistance against the cooling air is reduced, the efficiency in
cooling of a rectifier and a stator winding is improved, and the
operation efficiency in a connecting process is improved by
disposing conductive connecting-members at the rear side of a
stator with respect to an end face of a fan unit in the axial
direction of the stator so that the conductive connecting-members
oppose the top of a coil-end group of the stator winding.
[0031] According to an aspect of the present invention, an
alternator comprises: a stator including a cylindrical stator core
provided with a plurality of slots extending in an axial direction
of the stator, the plurality of slots being disposed in parallel to
each other along the circumference of the stator, and a stator
winding mounted in the plurality of slots of the cylindrical stator
core, the stator winding including n-sets (n represents a natural
number) of a three-phase alternating winding, each set of the
three-phase alternating winding being constructed by connecting
winding phase groups for three phases offset from each other by an
electrical angle of 120 degrees into an alternating connection; a
rotor enclosed by the cylindrical stator core; a fan unit mounted
on the rotor; and a rectifier, wherein the stator winding comprises
first wave-shaped windings and second wave-shaped windings, the
first wave-shaped windings being composed of 3n first winding
sub-portions each having one turn constructed by winding in a
wave-shape a strand of wire so as to alternately occupy an inner
layer and an outer layer in a slot-depth direction within the slots
at every 3.multidot.nth slot, the first winding sub-portions being
disposed at a pitch of one slot from each other, and the second
wave-shaped windings being composed of 3n second winding
sub-portions each having one turn constructed by winding in a
wave-shape the strand of wire so as to alternately occupy the inner
layer and the outer layer in the slot-depth direction within the
slots at every 3.multidot.nth slot and so as to be inversely wound
and offset by an electrical angle of 180 degrees relative to the
first winding sub-portions, the second winding sub-portions being
disposed at a pitch of one slot from each other, whereby m-pairs (m
represents a natural number) of the first wave-shaped windings and
the second wave-shaped windings are disposed so as to arrange
alternately and in a row in-slot-received portions of the first
winding sub-portions and in-slot-received portions of the second
winding sub-portions in the slot-depth direction within each of
said slots; wherein each set of the three-phase alternating winding
is formed by connecting a plurality of lead wires to each other
extending from the first winding sub-portions and the second
winding sub-portions via a conductive relay member, and connecting
into the alternating connection the three winding phase groups each
composed of the first winding sub-portions and the second winding
sub-portions which are mounted in every 3.multidot.nth slot; and
wherein the conductive relay member opposes the top of a coil-end
group of the stator winding across a gap therebetween.
[0032] The fan unit may be fixed to the rotor at least one end
thereof, the rectifier may be disposed at a side of the rotor to
which the fan unit is fixed, the conductive relay member may be
disposed at the side of the rotor to which the fan unit is fixed
and be disposed opposite to the rotor with respect to an end face
of the fan unit in the axial direction of the rotor, the plurality
of lead wires may serve as alternating-output lead wires for the
three-phase alternating winding, the conductive relay member may
serve as conductive alternating-output-relay members having
alternating-current-output-connection terminals extending inwardly
in the radial direction of the rotor, and the alternating-output
lead wires may be connected to the conductive
alternating-output-relay members and be connected to the rectifier
via the alternating-current-output-connection terminals.
[0033] The plurality of lead wires may serve as
neutral-point-connection lead wires for the winding phase group,
the conductive relay member may serve as a conductive
neutral-point-relay member, and the neutral-point-connection lead
wire for each phase may be integrally connected to the conductive
neutral-point-relay member.
[0034] The conductive neutral-point-relay member may include a
neutral-point-connection terminal extending inwardly in the radial
direction of the stator, and the neutral-point-connection terminal
may be connected to the rectifier.
[0035] The plurality of lead wires may serve as bridge-connection
lead wires between the first winding sub-portions and the second
winding sub-portions, the conductive relay member may serve as
conductive bridge-connection-relay members, and the
bridge-connection lead wires may be connected to the conductive
bridge-connection-relay members, whereby the first winding
sub-portions and the second winding sub-portions are
bridge-connected.
[0036] The plurality of lead wires may extend in parallel to each
other from the first winding sub-portions and the second winding
sub-portions in the axial direction, and may be connected to the
conductive relay member substantially at the same predetermined
level as each other from an end face of the stator core.
[0037] The conductive relay member and an insulative resin member
may be formed integrally with each other.
[0038] The stator may be formed so that the coil-end group of the
stator winding does not overlap the fan unit in the radial
direction.
[0039] The size of the conductive relay member in a radial
direction of the stator may be not greater than the size of the
coil-end group of the stator winding in the radial direction of the
stator.
[0040] The strand of wire may be a continuous conductive wire, and
the first winding sub-portion and the second winding sub-portion
may form each of the first wave-shaped windings wound in one turn
and each of the second wave-shaped windings wound in one turn,
respectively.
[0041] The each pair of the first wave-shaped windings and the
second wave-shaped windings may be formed with a winding assembly
composed of a plurality of the first winding sub-portions and a
plurality of the second winding sub-portions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a sectional view of an automotive alternator
according to an embodiment of the present invention;
[0043] FIG. 2 is a perspective view showing part of a strand of
wire constituting a stator winding used in the automotive
alternator shown in FIG. 1;
[0044] FIG. 3 is a diagram explaining arrangement of the strands of
wire constituting the stator winding used in the automotive
alternator shown in FIG. 1;
[0045] FIG. 4A is an end view of a winding assembly constituting
the stator winding used in the automotive alternator shown in FIG.
1;
[0046] FIG. 4B is a plan view of the winding assembly constituting
the stator winding used in the automotive alternator shown in FIG.
1;
[0047] FIG. 5 is a rear-end view explaining connections in one
phase of the stator winding used in the automotive alternator
according to the embodiment of the present invention;
[0048] FIG. 6 is a rear-end view explaining connections in three
phases of the stator winding used in the automotive alternator
according to the embodiment of the present invention;
[0049] FIG. 7 is a perspective view of a stator used in the
automotive alternator according to the embodiment of the present
invention;
[0050] FIG. 8 is a perspective view of a rectifier used in the
automotive alternator according to the embodiment of the present
invention;
[0051] FIG. 9 is a plan view of the rectifier used in the
automotive alternator according to the embodiment of the present
invention;
[0052] FIG. 10 is a perspective view showing the mounting of the
stator to the rectifier, used in the automotive alternator
according to the embodiment of the present invention;
[0053] FIG. 11 is a sectional view of a known automotive alternator
proposed in Japanese Patent Application No. 2000-011704;
[0054] FIG. 12 is a perspective view of a stator used in the known
automotive alternator;
[0055] FIG. 13 is a rear-end view explaining connections in one
phase of the stator winding used in the known automotive
alternator;
[0056] FIG. 14 is a perspective view of a three-phase-connection
terminal-assembly used in the stator of the known automotive
alternator;
[0057] FIG. 15 is an illustration explaining a method of the
connection between the stator winding and a rectifier used in the
known automotive alternator; and
[0058] FIG. 16 is a block diagram of a circuit used in the known
automotive alternator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0059] An embodiment according to the present invention is
described below with reference to the drawings.
[0060] FIG. 1 is a sectional view of an automotive alternator
according to an embodiment of the present invention. FIG. 2 is a
perspective view showing part of a strand of wire constituting a
stator winding used in the automotive alternator. FIG. 3 is a
diagram explaining arrangement of the strands of wire constituting
the stator winding used in the automotive alternator. FIG. 4A is a
rear-end view of a winding assembly constituting the stator winding
used in the automotive alternator, and FIG. 4B is a plan view of
the same. FIG. 5 is a rear-end view explaining connections in one
phase of the stator winding used in the automotive alternator. FIG.
6 is a rear-end view explaining connections in three phases of the
stator winding used in the automotive alternator. FIG. 7 is a
perspective view of a stator used in the automotive alternator.
FIGS. 8 and 9 are a perspective view and a plan view, respectively,
of a rectifier used in the automotive alternator. FIG. 10 is a
perspective view showing the mounting of the stator to the
rectifier used in the automotive alternator according to the
embodiment of the present invention.
[0061] In FIG. 1, a stator 8 has a size, including coil-end groups
16f and 16r of a stator winding 16, in the axial direction of a
rotor 7 smaller than that of the rotor 7 in the same direction. The
coil-end groups 16f and 16r are disposed so as not to overlap a fan
unit 5 in a radial direction of the stator winding 16. The stator
winding 16 is connected in an alternating connection by
three-phase-connection terminal-assemblies 60. The
three-phase-connection terminal-assemblies 60 are disposed at the
rear side with respect to an end face of the fan unit 5 in the
axial direction of the stator so as to oppose the top of the
coil-end group 16r of the stator winding 16.
[0062] The other configuration is the same as that of a known
alternator shown in FIG. 11.
[0063] According to the embodiment 1, since the
three-phase-connection terminal-assemblies 60 are disposed at the
rear side with respect to an end face of the fan unit 5 in the
axial direction of the stator so as to oppose the top of the
coil-end group 16r of the stator winding 16, the
three-phase-connection terminal-assemblies 60 are displaced from a
space formed between the coil-end group 16r and a rectifier 12,
which is an air flowing path from the fan unit 5. Therefore, the
wind resistance against the cooling air in the space between the
coil-end group 16r and the rectifier 12 is reduced, and the volume
of cooling air increases. As a result, the rectifier 12 and the
stator winding 16 can be cooled efficiently, thereby suppressing
the heat-up of the rectifier 12 and the stator winding 16, and the
high output of the alternator can be realized. Moreover, wind noise
can be reduced compared with the known automotive alternator in
which the three-phase-connection terminal-assemblies 100 are
disposed in that space when the volume of cooling air is the
same.
[0064] Since the coil-end groups 16f and 16r of the stator 8 are
disposed so as not to overlap the fan unit 5 in a radial direction
of the stator winding 16, the wind resistance against the cooling
air is more reduced, and the above-described efficiency can be more
improved.
[0065] The components of the alternator are described below.
[0066] With reference to FIGS. 2, 3, 4A, and 4B the winding
structure of the stator winding 16 is described.
[0067] A strand of wire 30 is made of a continuous copper wire
having a rectangular section and coated with an insulative film 49.
The strand of wire 30, as shown in FIG. 2, is formed by bending it
into a planar pattern in which straight portions 30b as
in-slot-received portions connected by turn portions 30a are lined
up at a pitch of six slots (6p). Adjacent straight portions 30b are
offset alternately by a distance equal to one width (w) of the
strands of wire 30 by means of the turn portions 30a.
[0068] In FIG. 3, two strands of wire 30 formed in such a pattern
are overlapped the straight portions 30b each other by being offset
by a pitch of six slots, thereby forming a wire-strand pair. Two
strands of wire 30 constituting the wire-strand pair are first and
second winding sub-portions 31 and 32 or third and fourth winding
sub-portions 33 and 34 which are described below. The wire-strand
pair are formed so that one strand of wire 30 is in a reverse
position with respect to the other strand of wire 30 by being
offset by an electrical angle of 180 degrees.
[0069] A winding assembly 39 shown in FIGS. 4A and 4B is
constructed by arranging six wire-strand pair so as to be offset by
a pitch of one slot from each other. Six ends of the strands of
wire 30 extend at each side of each end of the winding assembly 39.
The turn portions 30a are arranged so as to line up in rows on the
sides of the winding assembly 39. In FIGS. 4A and 4B, lead wires,
which are described below, are omitted.
[0070] Two winding assemblies 39 thus arranged are mounted so as to
stack up within slots 15a of a stator core 15, thereby forming a
stator before wire-connection. The strands of wire 30 are connected
by welding to each other at the ends extending at the ends of the
winding assemblies 39, whereby twenty-four wave-shaped windings
each having one turn and mounted on the stator core 15 are
obtained.
[0071] The winding structure of winding phase group 161 for one
phase (phase a) is described with reference to FIG. 5. In FIG. 5,
the wires 30 disposed at the rear side of the stator are shown by
solid lines, and the wires 30 at the front side thereof are shown
by dotted lines.
[0072] The winding phase group 161 for a phase a include first to
fourth winding sub-portions 31 to 34, each winding sub-portion
being formed with one strand of wire 30. The first winding
sub-portion 31 is formed in a manner such that one strand of wire
30 is wound in a wave-shape into every sixth slot from slot number
1 to 91 so as to alternately occupy a first address and a second
address inside the slots 15a, and the both ends of the strand of
wire 30 are connected to each other, thereby forming the
wave-shaped winding sub-portion in one turn. The second winding
sub-portion 32 is formed in a manner such that one strand of wire
30 is wound in a wave-shape into every sixth slot from slot number
1 to 91 so as to alternately occupy the second address and the
first address inside the slots 15a, and the both ends of the strand
of wire 30 are connected to each other, thereby forming the
wave-shaped winding sub-portion in one turn. The third winding
sub-portion 33 is formed in a manner such that one strand of wire
30 is wound in a wave-shape into every sixth slot from slot number
1 to 91 so as to alternately occupy a third address and a fourth
address inside the slots 15a, and the both ends of the strand of
wire 30 are connected to each other, thereby forming the
wave-shaped winding sub-portion in one turn. The fourth winding
sub-portion 34 is formed in a manner such that one strand of wire
30 is wound in a wave-shape into every sixth slot from slot number
1 to 91 so as to alternately occupy the fourth address and the
third address inside the slots 15a, and the both ends of the strand
of wire 30 are connected to each other, thereby forming the
wave-shaped winding sub-portion in one turn. The strands of wire 30
are arranged to line up in a row of four strands within each slot
15a with the longitudinal direction of their rectangular
cross-sections aligned in a radial direction.
[0073] Portions of the strands of wire 30 of the second and fourth
winding sub-portions 32 and 34 extending from slot numbers 55 and
61 at an end surface of the stator core 15 are cut, respectively,
and portions of the strands of wire 30 of the first and third
winding sub-portions 31 and 33 extending from slot numbers 61 and
67 at the end surface of the stator core 15 are cut, respectively.
Then, a cut end 31b of the first winding sub-portions 31 and a cut
end 33a of the third winding sub-portion 33 are connected by arc
welding or the like, a cut end 32b of the second winding
sub-portions 32 and a cut end 34a of the fourth winding sub-portion
34 are connected by arc welding or the like, and a cut end 33b of
the third winding sub-portions 33 and a cut end 34b of the fourth
winding sub-portion 34 are connected by arc welding or the like.
Thus, the winding phase group 161 in four turns for the phase a is
formed with the first to fourth winding sub-portions 31 to 34
connected to each other in series.
[0074] Cut ends 31a and 32a of the first and second winding
sub-portions 31 and 32, respectively, serve as a neutral-point lead
wire Na and an alternating-current-output lead wire Oa for the
phase a, respectively. The cut ends 33b and 34b of the third and
fourth winding sub-portions 33 and 34, respectively, serve as
bridge-connection lead wires for the phase a.
[0075] In the same manner, other five sets of four winding
sub-portions are disposed in every sixth slot 15a. Thus, the
winding phase groups 161 are formed for six phases, each set of
four winding sub-portions being offset from the other by one slot.
FIG. 6 shows connections in the winding sub-portions 161 for three
phases (phases a, b, and c).
[0076] Each strand of wire 30 constituting the first to fourth
winding sub-portions 31 to 34 is wound in a wave-shape in a manner
such that the strand of wire 30 extends from one of the slots 15a
at an end face of the stator core 15, is folded back outside the
slots 15a and is inserted in another slot 15a disposed away across
five slots 15a therebetween. Each strand of wire 30 is wound so as
to occupy alternately the inner layer and the outer layer with
respect to the slot-depth direction (radial direction) in every
sixth slot.
[0077] The strand of wire 30 extend outwards from each of the slots
15a at the end faces of the stator core 15 and is folded back to
form turn portions 30a served as coil ends. The turn portions 30a
which are formed into substantially the same shape at both ends of
the stator 15 are mutually spaced circumferentially and radially,
and arranged neatly in two rows circumferentially, to form coil-end
groups 16f and 16r.
[0078] With reference to FIG. 7, the configuration of the
three-phase-connection terminal-assembly 60 is described below.
[0079] The three-phase-connection terminal-assembly 60 includes a
conductive neutral-point-connection member 61, three conductive
alternating-current-output-connection members 62, three conductive
bridge-connection members 63, and an insulative resin member 64
formed integrally with each other. The conductive
neutral-point-connection member 61 made by pressing a metallic
plate such as a copper plate includes three connection tabs 61a and
a neutral-point-connection terminal 61b. Each conductive
alternating-current-output-connection member 62 made by pressing a
metallic plate such as a copper plate includes a connection tab 62a
and an alternating-current-output-connectio- n terminal 62b. Each
conductive bridge-connection member 63 made by pressing a metallic
plate such as a copper plate includes two connection tabs 63a.
[0080] The three conductive alternating-current-output-connection
members 62 are disposed in line along the circumference of the
stator 8 at the inner side of connecting parts 61c connecting the
connection tabs 61a of the conductive neutral-point-connection
member 61. The three conductive bridge-connection members 63 are
disposed in line along the circumference of the stator 8 at the
outer side of the connecting parts 61c. The conductive
neutral-point-connection member 61, the conductive
alternating-current-output-connection members 62, and the
conductive bridge-connection members 63 are disposed on the same
plane. The neutral-point-connection terminal 61b and the
alternating-current-output-- connection terminal 62b extend
inwardly in the radial direction. A width D of the
three-phase-connection terminal-assembly 60 including the
conductive connection-members 61, 62, and 63 is smaller than that
of the coil-end group 16r in a radial direction of the stator
8.
[0081] The configuration of the rectifier 12 is described below
with reference to FIGS. 8 and 9.
[0082] The rectifier 12 includes a pair of semicircular heat sinks
120 and 121 coaxially disposed with the major surfaces thereof
facing in the same direction as each other. A semicircular circuit
board 122 is laminated on the heat sinks 120 and 121 at the major
surface thereof. Eight diodes 29 are fixed to the major surface of
each of the heat sinks 120 and 121. The circuit board 122 is
provided with eight connection-terminals 122a, each connecting one
of the diodes 29 disposed on the major surface of the heat sink 120
with one of the diodes 29 disposed on the major surface of the heat
sink 121. The connection terminal 122a is provided with a threaded
hole 122b.
[0083] A method of manufacturing of the stator 8 is described as
follows.
[0084] Two winding assemblies 39 are stacked one on top of the
other and are mounted on a parallelepiped stator core (not shown)
at the slots 15a formed thereon. The parallelepiped stator core
mounted with the winding assemblies 39 is rolled up in a
cylindrical shape and its ends abutted and welded each other. Thus,
the cylindrical stator core 15 is formed.
[0085] The strands of wire 30 constituting the winding assemblies
39 are connected at the ends thereof, thereby forming the stator 8
including the stator core 15 mounted with twenty-four wires of the
first to fourth winding sub-portions 31 to 34, each being wound in
one turn. In the same set of the first to fourth winding
sub-portions 31 to 34 mounted in the same slots disposed at a pitch
of six slots, as shown in FIG. 5, the first and third winding
sub-portions 31 and 33 are connected at cut ends 31b and 33a,
respectively, and the second and fourth winding sub-portions 32 and
34 are connected at cut ends 32b and 34a, respectively. The cut
ends 31a, 32a, 33b, and 34b of the first to fourth winding
sub-portions 31 to 34, respectively, extend to the same level as
each other in the axial direction and in parallel to each
other.
[0086] Each three-phase-connection terminal-assembly 60 is disposed
opposing the top of the coil-end group 16r so that the cut ends
31a, 32a, 33b, and 34b of the first to fourth winding sub-portions
31 to 34 for each phase are disposed so as to abut on one of the
connection tabs 61a of the conductive neutral-point-connection
member 61, on the connection tab 62a of one of the conductive
alternating-current-output-connection members 62, and on the two
connection tabs 63a of one of the conductive bridge-connection
members 63, respectively. The cut ends 33b and 34b of the third and
fourth winding sub-portions 33 and 34 for each phase, respectively,
are connected to the two connection tabs 63a of the conductive
bridge-connection member 63, whereby the winding phase group 161 in
four turns for each phase is formed with the first to fourth
winding sub-portions 31 to 34. By connecting the cut end 31a of the
first winding sub-portion 31 for each phase to the individual
connection tabs 61a of the conductive neutral-point-connection
member 61, each three-phase alternating winding 160 is formed with
the three winding phase groups 161 connected into a star
connection. By connecting the cut end 32a of the second winding
sub-portion 32 for each phase to the connection tab 62a of each
conductive alternating-current-output-connecti- on member 62,
output terminals of the three-phase alternating winding 160 are
connected to the alternating-current-output-connection terminals
62b of the three conductive alternating-current-output-connection
members 62. Thus, the stator 8 including the stator winding 16
connected into an alternating connection by the
three-phase-connection terminal-assemblies 60 is formed as shown in
FIG. 7.
[0087] The stator 8 thus formed is mounted in the case 3 in a
manner such that the stator 8 and the rectifier 12 are positioned
so that the three-phase-connection terminal-assemblies 60 oppose
the circuit boards 122, as shown in FIG. 10. The
neutral-point-connection terminal 61b and the
alternating-current-output-connection terminals 62b of each
three-phase-connection terminal-assembly 60 are connected to the
rectifier 12 by being fixed by screws 38 to the threaded holes 122b
of the connection terminals 122a of the circuit board 122 included
in the rectifier 12. Thus, circuits shown in FIG. 16 are formed
with two sets of the three-phase alternating winding 160, each set
including the star-connected winding phase groups 161 for three
phases connected to the rectifier 12. The direct-current outputs of
the rectifiers 12 are combined by being connected to each other in
parallel.
[0088] According to the present embodiment, the cut ends 32a of the
second winding sub-portions 32, which are alternating-output lead
wires of the three-phase alternating windings 160, are connected to
the connection tabs 62a of the conductive alternating-output-relay
members 62 having the alternating-current-output-connection
terminals 62b, whereby each three-phase alternating winding 160 can
be connected to the rectifier 12 by connecting the
alternating-current-output-connection terminals 62b to the
connection terminals 122a of the circuit boards 122 of the
rectifier 12. Therefore, operations of fixing metallic
connection-terminals to the alternating-output lead wires and
bending the lead wires inwardly in the radial direction, which are
necessary in the known alternator, are not required, thereby
improving the efficiency in a connection process.
[0089] The cut ends 31a of the three first winding sub-portions 31,
which are the neutral-point lead wires, of the winding phase groups
161 for three phases, respectively, are connected to the three
connection tabs 61a, respectively, of the conductive
neutral-point-connection member 61. Therefore, operations of
leading three neutral-point lead wires to one position, twisting
the three lead wires, and soldering them, which are necessary in
the known alternator, are not required, thereby improving the
efficiency in a connection process. Since the
neutral-point-connectio- n terminal 61b is provided formed
integrally with the conductive neutral-point-connection member 61,
operations of fixing metallic connection-terminals to the
neutral-point lead wires and bending the lead wires inwardly in the
radial direction, which are necessary in the known alternator, are
not required, thereby improving the efficiency in a connection
process.
[0090] The third and fourth winding sub-portions 33 and 34 are
bridge-connected to each other by connecting the cut ends 33b and
34b of the third and fourth winding sub-portions 33 and 34,
respectively, which are bridge-connection lead wires between the
third and fourth winding sub-portions 33 and 34 to the connection
tabs 63a of the conductive bridge-connection member 63. Therefore,
operations of leading three bridge-connection lead wires of each
winding sub-portion to one position, twisting the three lead wires,
and soldering them, which are necessary in the known alternator,
are not required, thereby improving the efficiency in a connection
process.
[0091] The neutral-point lead wires, the alternating-output lead
wires, and the bridge-connection lead wires extend from the
coil-end group 16r in the axial direction in parallel to each
other, and are connected to the conductive relay members 61, 62,
and 63, respectively, at substantially the same predetermined level
from an end face of the stator core 15, thereby improving the
efficiency in a connection process.
[0092] The conductive relay members 61, 62, and 63 are formed
integrally to each other by the insulative resin 64, whereby the
conductive relay members 61, 62, and 63 are easy to handle in
assembling.
[0093] The width D of the conductive relay members 61, 62, and 63
in a radial direction of the stator is smaller than that of the
coil-end group 16r of the stator winding 16, whereby the space
between the rotor 7 and the conductive relay members 61, 62, and 63
is kept large, thereby providing flexible design options for the
components such as the fan unit 5.
[0094] Since each of the first to fourth winding sub-portions 31 to
34 is formed in a wave-shaped winding in one turn with a continuous
conductive wire, the number of connecting points can be greatly
reduced compared with a known alternator in which short copper
wires formed substantially in a U-shape are used. Therefore, the
productivity and yield ratio are improved, the height to which the
coil ends extend outwards from the stator core 15 is reduced, and
the exposure area of the coil ends is increased, whereby a
high-output alternator reduced in size can be obtained.
[0095] The winding sub-portions are formed with the individual
winding assemblies 39 which include wave-shaped wires in one turn,
whereby the insulative films 49 are prevented from being damaged
during the mounting on the stator core 15. The insulation can be
secured, and the number of turns can be easily increased as
needed.
[0096] Although according to the present embodiment, a copper wire
having a rectangular section is used in a strand of wire, the shape
of the strand of wire is not limited to that, and a copper wire
having a circular section may, for example, be used. With this
arrangement, the strand of wire can be formed more easily, and the
connection of the strands of wire to the conductive relay members
is more easily performed, thereby improving the productivity. The
strand of wire is not limited to a copper wire, and it may, for
example, be an aluminum wire.
[0097] Although according to the present embodiment, a continuous
wire is used as the strand of wire, a conductor segment of a short
copper wire formed substantially in a U-shape may be used, by which
the same effect can be obtained.
[0098] Although in the present embodiment, the stator winding are
used in an automotive alternator, the stator winding may be used in
an alternator for other use.
[0099] Although according to the embodiment 1, the fan unit 5 is
provided inside the case 3 formed the front and rear brackets 1 and
2, the fan unit may be provided outside the case, by which the same
effect can be obtained.
[0100] Although according to the present embodiment, the conductive
relay members are disposed at the rear side with respect to the
stator, the conductive relay members may be disposed at the front
side with respect to the stator without covering the portions of
the front-end coil-end group of the stator winding opposing a fan
fixed to a front end surface of the rotor, and only the
alternating-output lead wires may be led out from the rear-end
coil-end group toward the rear side. With this arrangement, the
wind resistance to the cooling air between the stator winding and
the rectifier can be suppressed and efficiency in the cooling of
the stator winding 16 at the front side can be maintained, thereby
providing the same effect.
[0101] Although according to the present embodiment, four strands
of wire are arranged so as to line up in a row radially within each
slot and the turn portions are arranged to line up in two rows
circumferentially to form coil-end groups, six strands of wire may
be arranged so as to line up in a row radially within each slot and
the turn portions may be arranged to line up in three rows
circumferentially to form coil-end groups. Or eight strands of wire
are arranged so as to line up in a row radially within each slot
and the turn portions are arranged to line up in four rows
circumferentially to form coil-end groups. As the number of the
strands of wire lined up within each slot increases, the number of
connection points increases. Therefore, when the conductive relay
members according to the present invention are not used, the wind
resistance against the cooling air increases, and the efficiency in
manufacturing operation decreases. The wind resistance against the
cooling air and the deterioration in the efficiency in the
manufacture can be suppressed by using the conductive relay members
according to the present invention.
[0102] As described above, the alternator according to the present
invention offers the following advantages.
[0103] The alternator according to the present invention comprises:
a stator including a cylindrical stator core provided with a
plurality of slots extending in an axial direction of the stator,
the plurality of slots being disposed in parallel to each other
along the circumference of the stator, and a stator winding mounted
in the plurality of slots of the cylindrical stator core, the
stator winding including n-sets (n represents a natural number) of
a three-phase alternating winding, each set of the three-phase
alternating winding being constructed by connecting winding phase
groups for three phases offset from each other by an electrical
angle of 120 degrees into an alternating connection; a rotor
enclosed by the cylindrical stator core; a fan unit mounted on the
rotor; and a rectifier, wherein the stator winding comprises first
wave-shaped windings and second wave-shaped windings, the first
wave-shaped windings being composed of 3n first winding
sub-portions each having one turn constructed by winding in a
wave-shape a strand of wire so as to alternately occupy an inner
layer and an outer layer in a slot-depth direction within the slots
at every 3.multidot.nth slot, the first winding sub-portions being
disposed at a pitch of one slot from each other, and the second
wave-shaped windings being composed of 3n second winding
sub-portions each having one turn constructed by winding in a
wave-shape the strand of wire so as to alternately occupy the inner
layer and the outer layer in the slot-depth direction within the
slots at every 3.multidot.nth slot and so as to be inversely wound
and offset by an electrical angle of 180 degrees relative to the
first winding sub-portions, the second winding sub-portions being
disposed at a pitch of one slot from each other, whereby m-pairs (m
represents a natural number) of the first wave-shaped windings and
the second wave-shaped windings are disposed so as to arrange
alternately and in a row in-slot-received portions of the first
winding sub-portions and in-slot-received portions of the second
winding sub-portions in the slot-depth direction within each of
said slots; wherein each set of the three-phase alternating winding
is formed by connecting a plurality of lead wires to each other
extending from the first winding sub-portions and the second
winding sub-portions via a conductive relay member, and connecting
into the alternating connection the three winding phase groups each
composed of the first winding sub-portions and the second winding
sub-portions which are mounted in every 3.multidot.nth slot; and
wherein the conductive relay member opposes the top of a coil-end
group of the stator winding across a gap therebetween. With this
arrangement, the wind resistance against cooling air at the top of
the stator winding is reduced, thereby improving the cooling
efficiency of the stator winding and improving the efficiency in an
alternating connection process, and a high output alternator
reduced in size can be obtained.
[0104] The fan unit may be fixed to the rotor at least one end
thereof, the rectifier may be disposed at a side of the rotor to
which the fan unit is fixed, the conductive relay member may be
disposed at the side of the rotor to which the fan unit is fixed
and be disposed opposite to the rotor with respect to an end face
of the fan unit in the axial direction of the rotor, the plurality
of lead wires may serve as alternating-output lead wires for the
three-phase alternating winding, the conductive relay member may
serve as conductive alternating-output-relay members having
alternating-current-output-connection terminals extending inwardly
in the radial direction of the rotor, and the alternating-output
lead wires may be connected to the conductive
alternating-output-relay members and be connected to the rectifier
via the alternating-current-output-connection terminals. With this
arrangement, the wind resistance against cooling air between the
stator winding and the rectifier is reduced, the cooling efficiency
of the rectifier and the stator winding, and the efficiency in an
alternating connection process can be improved.
Lead-wire-processing operations of fixing metallic
connection-terminals to the alternating-output lead wires and
bending the lead wires inwardly in the radial direction for
connecting the lead wires to the rectifier are not necessary,
thereby improving the efficiency in a connection process.
[0105] The plurality of lead wires may serve as
neutral-point-connection lead wires for the winding phase group,
the conductive relay member may serve as a conductive
neutral-point-relay member, and the neutral-point-connection lead
wire for each phase may be integrally connected to the conductive
neutral-point-relay member. Therefore, lead-wire-processing
operations of drawing the neutral-point lead wires, gathering the
same in a position, twisting the lead wires, and soldering the same
are not necessary, thereby improving the efficiency in a connection
process.
[0106] The conductive neutral-point-relay member may include a
neutral-point-connection terminal extending inwardly in the radial
direction of the stator, and the neutral-point-connection terminal
may be connected to the rectifier. Therefore, lead-wire-processing
operations of fixing metallic connection-terminals to the
neutral-point lead wires and bending the lead wires inwardly in the
radial direction of the stator for connecting the lead wires to the
rectifier are not necessary, thereby further improving the
efficiency in a connection process.
[0107] The plurality of lead wires may serve as bridge-connection
lead wires between the first winding sub-portions and the second
winding sub-portions, the conductive relay member may serve as
conductive bridge-connection-relay members, and the
bridge-connection lead wires may be connected to the conductive
bridge-connection-relay members, whereby the first winding
sub-portions and the second winding sub-portions are
bridge-connected. With this arrangement, lead-wire-processing
operations of drawing a plurality of bridge-connection lead wires,
gathering the same in a position, twisting the lead wires, and
soldering the same are not necessary, thereby improving the
efficiency in a connection process.
[0108] The plurality of lead wires may extend in parallel to each
other from the first winding sub-portions and the second winding
sub-portions in the axial direction, and may be connected to the
conductive relay member substantially at the same predetermined
level as each other from an end face of the stator core, thereby
improving the efficiency in a connection process.
[0109] The conductive relay member and an insulative resin member
may be formed integrally with each other. Therefore, it is easy to
handle the conductive relay member, thereby improving the
efficiency in an assembly process.
[0110] The stator may be formed so that the coil-end group of the
stator winding does not overlap the fan unit in the radial
direction. Therefore, the resistance to airflow is reduced, thereby
improving the cooling efficiency in the rectifier and the stator
winding.
[0111] The size of the conductive relay member in a radial
direction of the stator may be not greater than the size of the
coil-end group of the stator winding in the radial direction of the
stator, whereby the space between the rotor and the conductive
relay member is increased, thereby providing flexible design
options for the components such as the fan.
[0112] The strand of wire may be a continuous conductive wire, and
the first winding sub-portion and the second winding sub-portion
may form each of the first wave-shaped windings wound in one turn
and each of the second wave-shaped windings wound in one turn,
respectively, enabling the number of connecting points to be
greatly reduced. Therefore, the productivity and yield ratio are
improved, the protrusion of the coil-end groups decreases, and the
exposure area of the coil-end groups increases, whereby a
high-output alternator reduced in size can be obtained.
[0113] The each pair of the first wave-shaped windings and the
second wave-shaped windings may be formed with a winding assembly
composed of a plurality of the first winding sub-portions and a
plurality of the second winding sub-portions. With this
arrangement, the insulative film are prevented from being damaged
during the mounting on the stator core. The insulation can be
secured, and the number of turns can be easily increased as
needed.
* * * * *