US2488079A

US2488079A - Induction clutch

Info

Publication number: US2488079A
Application number: US637223A
Authority: US
Inventors: Lavaud Dimitri Sensaud De; Milde Charles Emmanuel
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-04-17
Filing date: 1945-12-26
Publication date: 1949-11-15
Anticipated expiration: 1966-11-15

Description

1949 D. SENSAUD DE LAVAUD ETAL 2,483,079

" INDUCTION CLUTCH Filed Dec. 26, 1945 1). @maud DeLava/w C E. JIzLLcZe Patented Nov. 15, 1949 2,488,079 INDUCTION CLUTCH Dimitri Sensaud de Lavaud and Charles Emmanuel Mlld, Paris, France Application December 26, 1945, Serial No. 637,223 In France April 17, 1945 4 Claims. 1

In the usual electromagnetic clutches hitherto known the engagement is effected by means of magnetic induction or attraction between, on one part, a driving inductor component formed by a homopolar magnetic body keyed to one shaft and provided with hollows in which are disposed conductors to constitute a squirrel cage, and, on the other part, a magnetic metal driven component or crown which is keyed to another shaft and provided with a holed rim and of which the relative rotation with respect to said driving component produces variations of magnetic flux.

When such clutches are applied to the automobile traction, it is expedient to make the driving shaft carry practically the most part, if not all, of the rotating masses. hence to secure the inductor component to the driving shaft and key to the driven shaft the hollowed crown the inertia of which is reduced. The drivinginductor component body thus substitutes itself for the usual fly wheel of the thermo-motor.

It is an object of the present invention to further reduce in weight the crown keyed to the driven shaft, by substituting for the hollowed magnetic metal crown a non-magnetic material crown having a peripheral rim provided with hollows into which are fitted small bars of magnetic metal, preferably embedded therein in the process of making, to form apparent poles of the component secured to the driven shaft.

Such crown may be made from any suitable non-magnetic material such, for example as light alloys; it may also be made from a non-metallic insulating material, preferably by molding.

Hollowed crowns made from magnetic metal have a known disadvantage in causing magnetic leakage and reducing the amplitude of flux variations, facts that decrease the intensity of induced currents, hence the torque.

It is therefore a further object of this invention to provide a novel crown such as to reduce as much as possible magnetic leakage and increase the amplitude of flux variations, hence the torque.

It will, of course, be possible, particularly with a view to increasing the torque at starting and in normal operation, as has already been proposed for devices of this kind. to provide several conductors in the squirrel cage per apparent pole of the crown.

Other objects of the present invention will be apparent from the following description dealing with an example of a non-magnetic metal crown comprising magnetic elements or small bars, applied to a squirrel cage asynchronous clutch and constituting the driven crown component of an induction clutch improved according to the invention.

The invention will be described with reference to the accompanying diagrammatic drawings in which:

Fig. 1 is a general axial sectional view showing the crown designed according to the invention;

Fig. 2 is a fragmentary sectional view through the line 11-11 of Fig. 1;

Fig. 3 is a fragmentary plan view of the crown with its apparent poles.

According to the invention, the clutch crown is cast from any suitable non-magnetic material such for example as certain known light alloys. In the mould containing the pattern there are disposed a desired number of small bars i of magnetic material, such for example as soft iron, which bars, after the metal is cast, remain embedded in the cast mass of a cylindric rim 2. The longitudinal and transversal sections of such bars are determined, as illustrated by Figs. 1 and 2. so as to cause them to stay fixed in the mass of cast material and keep so in despite of centrifugal magnetic deflections liable to be exerted thereupon.

In the example shown, the bars are inclined with respect to the corresponding radial planes, as illustrated by Fig. 3; this contributes to the silent operation of the clutch. The width and distribution of the bars I define the width and distribution of apparent poles of the rim 2 or operational part of the crown engaged into the magnetic flux of the inductor component, formed by a magnetic body keyed on a drive shaft 5|, which magnetic body includes the elements 54, 54a, and 54b having squirrel cages comprising polar pieces Sic, Blb, conducting rings 63a and 63b, through which the winding 56 develops a magnetic field indicated generally by the line ill.

The crown is centered and secured by its cheek-plate 3 to a hub 4 as by means of rivets 5, which permits this component to be keyed to the driven shaft 53 of the clutch.

Finally, there are provided weight reducing and ventilation openings 6 in the rim 2 between the bars i, and similar openings 1 in the cheekplate 3.

What we claim is:

1. Electromagnetic clutch comprising in combination driving and driven shafts a magnetic homopolar inductor fitted with squirrel cages and keyed to one of said shafts, and a holed crown keyed to the other of said shafts and producing. when relatively rotated with respect to said inductor, variations of magnetic flux, said crown each bar correspond several conductors in the being made from non-magnetic material and having a peripheral rim provided with spaced holes, and small bars of magnetic material lodged in said holes and forming apparent poles of said OI'OWII.

2. Electromagnetic clutch comprising in combination driving and driven shafts a magnetic homopolar inductor fitted with squirrel cages and keyed to one of said shafts, and a holed crown keyed to the other of said shafts and producing, when relatively rotated with respect to said inductor, variations of magnetic flux, said crown being made from non-magnetic material and having a peripheral rim, and spaced small bars of magnetic material embedded in said rim, said bars forming apparent poles of said crown.

3. Electromagnetic clutch comprising in combination driving and driven shafts a magnetic homopolar inductor fitted with squirrel cages and keyed to one of said shafts, and a holed crown keyed to the other of said shafts and producing. when relatively rotated with respect to said inductor, variations of magnetic flux, said crown being made from non-magnetic material and having a peripheral rim, and spaced small bars of magnetic material on said rim, said bars forming apparent poles of said crown so that to squirrel cage.

4. Electromagnetic clutch comprising in combination driving and driven shafts a magnetic homopolar inductor fitted with squirrel cages and keyed to one of said shafts. and a holed crown keyed to the other of said shafts and producing, when relatively rotated with respect to said inductor, variations of magnetic flux, said crown being made from non-magnetic material and having a peripheral rim, and spaced bars of magnetic material on said rim, said bars being inclined with respect to corresponding radial planes 0; said crown and forming apparent poles there- 0 DIMITRI BENSAUD or LAVAUD. CHARLES EMMANUEL Mnmt.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,357,517 Burdick Sept. 5, 1944 2,392,148 Hornbostel Jan. 1, 1946 2,396,000 Findley Mar. 5, 1946 2,409,557 Gilflllan Oct. 15, 1948