JPH0127406Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle alternator that improves the cooling efficiency of stator coils.

In the conventional method of winding the stator coil of a vehicle alternator, the height of the coil end is the first phase, the second phase
Normally, both phase and third phase coils are wound indiscriminately at almost the same height, and the outermost third phase coil in the slot is the innermost first phase coil. It is now hidden behind the coils of the However, in the structure of a conventional vehicle alternator that has a fan on the end face of the rotor for cooling,
Since the cooling passage is sucked in from the front and rear axial directions and discharged radially, the stator coil on the inner diameter side near the fan is directly cooled by the cooling air and is very well cooled, whereas the stator coil on the outer diameter side is The coil is hidden behind the coil on the inner diameter side, so no cooling air hits it, and the temperature becomes extremely high, so you have to decide on the wire type and diameter that can withstand the temperature on the outer diameter side, which has the disadvantage of increasing costs. Ta.

This invention adopts a wave winding method for the stator coil, and by winding each layer coil unit in a flat shape, the surface area of the coil wire is exposed to the maximum amount of cooling air, and each layer coil unit is wound in a flat manner. It is an object of the present invention to provide an alternator for a vehicle in which the surface area of all coil units is exposed to the maximum without the units blocking each other's cooling air, thereby improving the cooling performance of the stator coil.

The present invention will be explained below with reference to FIGS. 1 to 7. FIG. 1 is a sectional view of essential parts of a vehicle alternator in which the present invention is implemented. A stator core 7 is fixed to the generator housing 2 on the outer periphery of the field rotor 4 having claw-shaped magnetic poles, and the stator coil 1 is wound around the stator core 7 in an aligned flat shape. Cooling fans 3a and 3b are provided on both end faces of the rotor 4, with the cooling fan 3a being a mixed flow fan and the cooling fan 3b being a centrifugal fan. More specifically, the stator coil 1 has the following configuration. That is, firstly, the three-phase all-pitch concentrated winding method is used, and each phase coil unit is as shown in Fig. 3.
As shown in Fig. 4, the coil unit 1a, 1b, 1c of each phase is housed in the slot of the stator core in order, and as shown in Fig. 3, the outermost phase coil unit and the middle layer coil unit , forming an inner layer coil unit. Second, each phase coil unit is formed by a substantially identical form coil unit winding frame, and when stored in the slot, each strand is shifted in the rotor axis direction as shown in FIG. As you can see, they are wrapped in an aligned flat shape. In other words, when the coil end portion of the stator coil is viewed from the side of the cooling fan provided on the rotor, substantially all of the coil wires are exposed in a portion of each coil end of each phase coil unit. It has a part.

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

When the field rotor 4 rotates, a rotating magnetic field is applied to the stator core 7, three-phase power is generated in the three-phase wound stator coil, and a DC output is supplied to the outside through a three-phase full-wave rectifier 8. Ru. A load current therefore flows through the stator coil 7, generating heat due to copper loss, but forced cooling air is supplied to the generator by the cooling fans 3a and 3b provided on both end faces of the field rotor 4. Incorporated from the outside, the first
As shown by the arrows in the figure, the cooling air 6b, 6c, 6d collides almost perpendicularly with the end of the stator coil 1, which is formed into an aligned flat shape, and furthermore, from the discharge ports 8a, 8b provided in the generator housing 2. It is discharged to the outside. As mentioned above, the coil wires in each coil unit are arranged in a flat shape as shown in Fig. 5 so that the projected area of the coil end portion viewed from the fan inner diameter side (rotor side) is as large as possible as shown in Fig. 4. Since the cooling air 6 is staggered, the cooling air 6
b, 6c, and 6d collide with most of the surface area of the coil wire, and the temperature of each coil end portion drops significantly.

The winding method shown in this embodiment employs a wave winding method, which has the effect of dramatically increasing the effect of increasing the cooling area by shifting the coil wires in the axial direction and making them aligned and flattened. In other words, in the case of lap winding, which is commonly used in vehicle alternators,
Even if the coil end of a certain phase is formed into a flat shape, the heat dissipation effect is limited because the coil wires have to be lined up so that the coil end portion of the other phase covers and hides it. It is possible to shift the coil ends for each coil unit so that they are not covered by other phases, but if that method is adopted, the overall height of the coil ends will be very high, and the coil unit winding frames will be uneven, resulting in electrical specifications. Moreover, there are disadvantages such as not only being undesirable but also not suitable for mass production. It is clear that in the case of the wave winding method shown in this embodiment, the overlap between the coil ends is drastically reduced, and all of the above problems are solved.

A graph that experimentally confirmed the stator coil cooling effect of the present invention is shown in Figure 6. In Figure 6, A shows the case where the stator coil is the conventional one, and B shows the case where the stator coil is the embodiment of the present invention. . As shown in the figure, there is a remarkable temperature reduction effect of about 30 to 40 degrees at the maximum temperature.
FIG. 7 shows a second embodiment of the stator coil of a vehicle alternator according to the present invention, and is a partial sectional view of the coil end corresponding to FIG. 5 showing the first embodiment. The difference from the illustration is that the coil wires are not arranged in a straight line.

However, since the coil wires are offset from each other in the axial direction so that all of the coil wires can be seen when viewed from the side of the cooling fan installed on the rotor, the wind blown from the cooling fan directly All the wires are cooled down, and the temperature rise is equal to the first
It is suppressed to the same extent as in the example.

In the above embodiment, since a diagonal flow fan is used as the cooling fan 3a, the cooling air flows in the radial direction 6b and along the inner circumference of the stator core 7 as shown in 6c, and then flows through the centrifugal fan 3b. Although it flows in the radial direction together with the cooling air flow 6b,
It goes without saying that a centrifugal fan may be used instead of the diagonal flow fan as the cooling fan 3a, and only the cooling air 6b may flow in the radial direction. The point is that the cooling air should finally collide with the stator coil end almost perpendicularly.

As mentioned above, the vehicle alternator according to the present invention is an internal fan type vehicle alternator in which a centrifugal cooling fan is provided on the end face of the rotor.
By using the three-phase all-pitch concentrated winding of the stator coil and the wave winding method for each phase stator coil unit, it is possible to form a part of each phase stator coil unit that does not overlap with the coil unit of other phases, and By forming the coil unit into a substantially flat shape in the axial direction and by providing a pair of centrifugal cooling fans at both ends of the rotor, the cooling air generated by the pair of cooling fans is applied to the coil wires at both ends of each coil unit. Direct and wide contact has the excellent effect of significantly increasing the cooling efficiency of the stator coil.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a first embodiment of a vehicle alternator according to the present invention, and FIG. 2 is a schematic diagram showing details of the stator coil mounting portion according to the present invention.
Figure 3 is a schematic diagram of the stator coil end seen from the axial direction of the stator core in Figure 1.
The figure is a schematic diagram of the stator coil end when looking at the outer circumference from the inner circumference of the stator core in Fig. 1.
The figure is a cross-sectional view taken along the line A-A shown in Figure 4, and is a schematic diagram of the stator coil end of the first embodiment of the present invention. Figure 6 shows the temperature rise characteristics of the stator coil, and shows the conventional winding. FIG. 7 is a diagram showing a comparison between the winding method and the winding method of the present invention, and is a schematic diagram of the stator coil end of the second embodiment of the present invention, which corresponds to FIG. 5. DESCRIPTION OF SYMBOLS 1... Stator coil, 2... Generator housing, 3a, 3b... Cooling fan, 4... Field rotor, 1a, 1b, 1c... Each phase of 3 phases, 6b,
6c, 6d... Indicates the direction of cooling air.

Claims (1)

[Claims for Utility Model Registration] A stator having a stator core and a stator coil wound around the stator core, a rotor provided on the inner periphery of the stator and having a rotating shaft, and a rotor provided at both ends of the rotor. A vehicular alternator is provided with a pair of centrifugal cooling fans that generate wind on the outer circumferential side in the radial direction to cool the stator coils. and consists of a coil unit of each phase consisting of a plurality of coil wires, and a wave winding method is used so that a part of the end of the coil unit remote from the side surface of the stator core does not overlap with each other, and a portion of the coil unit is formed into a substantially flat shape by expanding the coil wire in the axial direction of the rotating shaft.