JPH0424939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alternator for a vehicle, and more particularly to an improved structure of a stator coil.

In the conventional winding method of the stator coil of a vehicle alternator, the coil end height is indiscriminately wound at almost the same height for the first, second, and third phases. Normally, the outermost third phase coil in the slot is hidden by the innermost first phase coil. However, in the conventional structure of an internal fan type vehicle alternator that has a fan on the end face of the rotor for cooling, the cooling passage is sucked in from the front and rear sides in the axial direction and discharged in the radial direction. The stator coils on the inner diameter side, which are closer to the fan, are cooled very well as they are directly hit by the cooling air, but on the other hand, the stator coils on the outer diameter side are hidden by the inner diameter side coils and are not hit by the cooling air at all, resulting in extremely high temperatures. Therefore, it is necessary to decide on the wire type and wire diameter that can withstand the temperature on the outer diameter side, which has the disadvantage of increasing costs.

In order to eliminate the above-mentioned drawbacks, the present invention has constructed a stator coil so that each component of the flow of cooling air to the stator coil generated by a fan in the housing is effectively utilized to efficiently cool the coil. The object of the present invention is to provide an alternator for a vehicle that has the following characteristics.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 is a longitudinal cross-sectional view of the essential parts of an alternator embodying the present invention, in which a field rotor 4 having claw-like magnetic poles is shown.
A stator core 7 is fixed to the housing 2 around the outer periphery of the rotor 4, a stator coil 1 is wound around the stator core 7, and cooling fans 3 are installed on both end surfaces of the rotor 4.
a and 3b are provided. The detailed configuration of the stator coil 1 is as follows. The first 3-phase all-node concentrated winding method, with 1 coil unit for each phase.
As shown in FIG. 2, the coils a, 1b, and 1c are housed in the slots of the stator coil in order to form an outermost coil unit, a middle coil unit, and an inner coil unit. Second, when storing each phase coil unit in the slot, shift each strand in the axial direction of the rotor as shown in FIG.
As shown in FIG. 3, they are wound in an aligned flat shape.
Thirdly, the inner and outer parts of this flat-wound coil are
Before forming the outer diameter and end height, a resin plate 8 is placed between each phase coil unit as shown in FIG. A gap 9 is formed between the units.

Next, the operation of the vehicular alternator having the stator coil configured as described above will be explained.

When the field rotor 4 rotates, the stator coil 1
Three-phase power is generated, DC output is supplied to the outside through a three-phase full-wave rectifier (not shown), and a load current flows through the stator coil 1, generating heat due to copper loss. Fan 3 installed in
As shown in FIG. 2, the cooling air 6 taken in from the outside of the alternator is twisted and agitated by the rotation of the rotor 4, and is pushed out while being twisted in the same direction as the rotational direction 6' of the rotor. After this hits the end of the stator coil 1 and cools the coil, the discharge port 8a provided in the housing 2,
It is discharged to the outside from 8b. At this time, the stator coil 1 is arranged so that the projected area of the coil end portion viewed from the inner diameter side of the fan (rotor side) is as large as possible as shown in FIG. As shown in the figure, the coil units are arranged in a flat, staggered manner, and a gap 9 is provided between each coil unit, so that the coil units are pushed out by the fan in the direction of the composite vector of the rotational direction, centrifugal direction, and axial direction. The cooling air 6 flows to the outside through the gap 9 along the side surface of the flat coil end. For this reason, the cooling air hits most of the surface area of the stator coil strands, and the temperature of the coil ends drops significantly.

The results of experimentally confirming the cooling effect of the stator coil of the vehicle alternator according to the present invention are shown in FIG. 7 as a temperature rise characteristic diagram of the stator coil, where A is for the conventional case and B is for the stator coil. When the coils are formed into aligned flat windings, C shows the case of the present invention in which the stator coils are formed into aligned flat windings and gaps are provided between the coil units. As shown in the figure, in the case of the present invention, there is a temperature reduction effect of about 40° C. at the maximum temperature.

In order to form a gap 9 between the coil units, each coil unit is covered with a resin cap 10 as shown in FIGS. 6a and 6b without intervening the resin plate 8 as described above. It may be molded and then removed. Further, in the above embodiment, the gap 9 is formed after the coil units are housed in the stator slots, but each coil unit may be molded in advance so as to create a gap between the coil units and then housed in the slots. .

As described above, in the present invention, in an internal fan type vehicle alternator in which a cooling fan is provided on the end face of the field rotor and the cooling fan rotates within the housing, a cooling fan is provided around the rotor of the field winding. It has a multiphase stator coil wound around an annular stator core, and each coil of the unit for each phase is connected to a coil end portion of the stator coil that protrudes from the stator core in the axial direction of the field rotor. The windings are shifted from each other in the axial direction so that each unit has a generally flat shape, and a gap is formed between the coil end portions of each unit in the radial direction of the stator core, and the cooling Since the circumferential component of the cooling air generated in the housing by the fan passes through the gaps between the units in the circumferential direction, each phase coil wire is uniformly cooled to the same level. In addition, there is a gap of a predetermined width between the coil ends of each unit, allowing the circumferential component of the cooling air to pass through, reducing ventilation resistance and increasing the circumferential air volume, which lowers the overall temperature of the stator coil. It has the excellent effect of reducing

[Brief explanation of drawings]

The accompanying drawings show an embodiment of the vehicle alternator according to the present invention, and FIG. 1 is a vertical cross-sectional view of the main parts of the vehicle alternator in which the present invention is implemented, and FIG. A schematic diagram of the stator coil end viewed from the axial direction. Figure 3 is a schematic diagram of the stator coil end seen from the outer circumference to the inner circumference of the stator core in Figure 1. Figure 4 is a longitudinal section along the - line shown in Figure 3. A top view, FIG. 5a is a schematic diagram of a resin plate,
FIG. 5b is a schematic diagram showing a method of forming gaps between the coil units of each phase using the plate shown in FIG. 5a,
Fig. 6a is a schematic diagram of a resin cap, Fig. 6b is a schematic diagram showing a method of forming a gap between each phase coil unit using the cap shown in Fig. 6a, and Fig. 7
The figure is a temperature rise characteristic diagram of the stator coil, and is a diagram showing a comparison between a conventional stator coil winding method, an aligned flat winding method, and a winding method according to the present invention. 1...Stator coil, 2...Housing, 3
a, 3b...Cooling fan, 4...Field rotor, 1
a, 1b, 1c... Coil unit for each phase, 9...
...Gap formed between each phase coil unit, 6...
Arrow indicating the direction of cooling air, 6'...Arrow indicating the rotation direction of the field rotor.

Claims (1)

[Claims] 1. In an internal fan type vehicle alternator in which a cooling fan is provided on the end face of the field rotor and the cooling fan rotates within a housing, the cooling fan is arranged around the rotor of the field winding. It has a multiphase stator coil wound around an annular stator core, and each coil winding of a unit for each phase is connected to a coil end portion of the stator coil that protrudes from the stator core in the axial direction of the field rotor. are shifted from each other in the axial direction so that each unit has a generally flat shape, and a space is formed between the coil end portions of each unit in the radial direction of the stator core, and the cooling fan An alternator for a vehicle, wherein a circumferential component of the cooling air generated in the housing passes through gaps between the units in the circumferential direction.