FR2498391A1 - Motor vehicle alternator construction - uses large dia. fan assembled by passage through stator case via slots cut in case to clear fan blade tips - Google Patents

Abstract

The motor vehicle alternator is constructed so that a large dia. front cooling fan can be retained yet allow low cost assembly by passing the cooling fan inside the stator casing before installation of the stator poles. The max. fan diameter is retained by cutting grooves for the passage of the fan blade tips in the stator wall. The alternator comprises a pulley driven by the engine and has the cooling fan mounted immediately behind the pulley. The blades of the fan force air over the rotor and stator, providing the forced cooling necessary in a compact alternator design. The two halves of the alternator shell are fitted over the stator laminations and require no bolt or screw coupling, simplifying construction.

Description

ALTERNATOR, ESPECIALLY FOR MOTOR VEHICLES
The invention relates to an alternator for motor vehicles, of the type comprising an internal fan, with fins, of diameter approximately equal to or greater than the diameter of engagement of a stator housed inside two bearings in which a shaft carrying a rotor, which shaft is driven into rotation by the internal combustion engine of the motor vehicle.

In this type of alternator, since the fan has a larger diameter than the diameter of the crown on which one of the faces of the stator sheet pack rests, it is necessary to provide this bearing in two pieces assembled between them by screws.

This leads to turning, drilling and tapping operations which consequently increase the price of denial.

If one wishes to reduce the cost price, by providing a bearing in one piece, one is led to reduce the diameter of the fan very greatly so that the fan can pass freely within the internal diameter of the crown on which the bundle of stator plates rests.

But in this case, the reduction in the diameter of the fan leads to an excessive increase in the heating of the alternator.

In order to maintain the temperature rise within acceptable limits, it is then necessary to increase the dimensions of the monetary engine in order to accommodate a fan of sufficient diameter.

This leads to an obstruction of the weight of the alternator, of its cost and sometimes to difficulties in mounting on the motor vehicle.

The object of the invention is to remedy these drawbacks and to this end relates to an alternator of the internal fan type, characterized in that it is provided inside the bearing, in which the fan turns, a plurality of notches , n number identical to the number of fins of the fan, which notches have a diometer greater than the diameter of the frontal crown on which the stator is supported.

The alternator according to the invention has the advantage that compared to previous embodiments, the cost price is reduced, by eliminating turning, drilling and tapping operations without the need to increase the dimensions of the alternator to house the fan inside the bearing provided in one piece.

The description which follows with reference to the appended drawings will make it easier to understand how the invention can be implemented.

Figure l is a longitudinal sectional view of the alternator object of the invention.

Figure 2 is a rear view of the fan and the bearing don which rotates the fan.

According to a preferred embodiment of the invention, the alternator shown in FIG. 1, includes an internal fan (1) with fins (la), a stator (2) constituted, in known manner, of a pack of sheets (2a) and phase windings (2b).

The stator (2) is fitted inside two bearings (3 and 4) in which rotates a shaft (5) carrying a rotor (6) constituted, in a known manner, of pole pieces (6a) of a core ( 6b) of an excitation winding (6c) and of current conducting rings (6d and 6.) on which come to brush brushes (not shown) of supply and output of excitation current.

The shaft (5) is rotated by the internal combustion engine (not shown) via a pulley (7).

The fan (13 is fixed to the pole piece (6a) by any known means, such as, for example, screws, rivets or by electrical welding, or else force-fitted onto the grooves (5a) of the shaft ( 5).

According to the invention, the bearing (3) is provided with a plurality of notches (32) (see FIG. 2) in a number identical to the number of fins (la) of the fan (1) which notches (3a) have a diameter # 1 1 greater than diameter 2 which, with the diameter% 3, constitutes a fragmented frontal crown (3b) on which the sheet metal plate (2a) of the stator (2) comes to bear (see FIG. 1).

We thus manage to lodge inside the bearing (3) obtained in a single piece, the fan (1; the diameter of which is sufficient to maintain the heating within acceptable limits.

Claims (1)

 CLAIM Alternator for motor vehicles, of the type comprising an internal fan (1), with fins (1a), of diameter approximately equal to or greater than the diameter of engagement of a stator (2) housed inside two bearings (3 and 4) in which rotates a shaft (5) carrying a rotor (6) characterized in that there is provided inside the bearing (3) a plurality of notches (3a) in noabre identical to the number of fins ( la) of the fan (1), which notches (3a) have a diometer # 1 greater than the diameter # 2 which constitutes, with the diometer # 3, a fragmented front crown (3b) on which the stator (2) is supported.