Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-01-29
2003-04-22
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S184000
Reexamination Certificate
active
06552463
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to armature winding structures of dynamo-electric machines. In particular, the present invention relates to a stator winding structure of an alternator, for example, an automotive alternator to be mounted on an automotive vehicle, such as an automobile or a truck.
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.
2. Description of the Related Art
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.
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. Also, 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 high Joule heat generated by the output current.
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 heat resistance, reduced noise, and the like must be complied with.
A structure for reducing the resistance of windings (heat loss), improving the space factor of electrical conductors, and lining up and concentration of coil ends was proposed disclosed in, for example, International Publication No. WO92/06527, in which short conductor segments having large cross-sections are used as electrical conductors of the stator winding.
In an alternator of this type, the reduction of turns of the stator winding for each phase is effective for reducing the armature raction which causes decrease in the output in a high-rotation range of, for example, 2000 to 5000 rpm. Particularly, the turns can be reduced by reducing the number of electrical conductors received in a slot, by which the flatness ratio (the size of the sections of the conductors in the slot-depth direction divided by the size of the same in the slot-width direction) of the electrical conductors increases. However, since short conductor segments formed in a U-shape by bending conductors having a rectangular section are used as the electrical conductors, it is difficult to form turn portions of the conductor segments as the flatness ratio of the electrical conductors increases. Therefore, it is necessary for reducing the turns for each phase of the stator winding to increase the number of the electrical conductors received in a slot so as to reduce the flatness ratio of the electrical conductors, thereby making the formation of the turn portions easy, and to connect in parallel the windings formed by connecting the electrical conductors.
A technology is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2000-92766, in which lap windings (loop windings) and wave windings each constructed by joining short conductor segments are connected in parallel to each other, thereby forming winding phase group for each phase of the stator winding.
As shown in
FIG. 19
, the known stator winding include three types of conductor segments
311
,
312
, and
313
made of a conductor having a rectangular section and formed substantially in a U-shape. Each of the conductor segments
311
,
312
, and
313
is inserted at the ends thereof in a pair of slots three slots apart (at a magnetic pole pitch) from an end of each slot in the axial direction, and the ends of the conductor segments
311
,
312
, and
313
extending from the other end of the same slots are connected to each other by welding or the like, thereby forming a coil of windings in four turns around the stator core. In each slot, six conductors are disposed alongside each other in a radial direction of the stator core, the six conductors being two sets of in-slot-received portions
311
a
,
312
a
, and
313
a
of the conductor segments
311
,
312
, and
313
, respectively. The positions in each slot which are occupied by the six in-slot-received portions
311
a
,
312
a
, and
313
a
are hereinafter referred to as first address, second address, . . . , sixth address from the innermost toward outer positions in a radial direction of the stator core. A turn portion
313
b
of the conductor segment
313
is covered by a turn portion
312
b
of the conductor segment
312
, and the turn portion
312
b
of the conductor segment
312
is covered by a turn portion
311
b
of the conductor segment
311
, at an axial end face of the stator core.
At an axial end opposite to the axial end of the stator core at which the turn portions
311
b
,
312
b
, and
313
b
protrude, an end
313
c
of the conductor segment
313
extending from the third address of a slot is connected to an end
313
c
of the other conductor segment
313
extending from the fourth address of another slot three slots apart, thereby forming two winding sub-portions
301
and
303
each constructed with a wave winding, each in one turn per slot. An end
311
c
of the conductor segment
311
extending from the first address of a slot is connected to an end
312
c
of the conductor segment
312
extending from the second address of another slot three slots apart, and the end
312
c
of the conductor segment
312
extending from the fifth address of a slot is connected to the end
311
c
of the conductor segment
311
extending from the sixth address of another slot three slots apart, thereby forming two winding sub-portions
302
and
304
each constructed with a lap winding, each in two turns per slot.
As shown in
FIG. 20
, each of winding phase groups for three phases, each in six turns, is formed by connecting in series the two winding sub-portions
301
and
303
, and the two winding sub-portions
302
and
304
. In
FIG. 21
, each of winding phase groups for each turn, each in three turns, is formed by connecting in series the winding sub-portion
301
and the winding sub-portion
302
, and the winding sub-portion
303
and the winding sub-portion
304
, and connecting in parallel the series-connected winding sub-portions
301
and
302
and the series-connected winding sub-portions
303
and
304
. Three sets of the winding phase groups thus formed are connected into an alternating connection, thereby forming a three-phase alternating winding constituting a stator winding, the stator winding being connected to a rectifier.
The known stator winding of an automotive alternator are formed in a manner such that three types of the conductor segments
311
,
312
, and
313
are inserted in a pair of slot separated by a distance of one magnetic-pole pitch from an end of the stator core so that the in-slot-received portions
311
a
,
312
a
, and
313
a
overlap each other, and the ends of the conductor segments
311
,
312
, and
313
extending from the other end of the stator core are connected to each other.
In the known stator winding formed as described above, the height of the coil ends of the stator winding at the end of the stator core
15
is increased, as shown in
FIG. 22
, whereby a problem has been found
Adachi Katsumi
Asao Yoshihito
Oohashi Atsushi
Cuevas Pedro J.
Mitsubishi Denki & Kabushiki Kaisha
Ramirez Nestor
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