GB1576831A

GB1576831A - Rotor for an electric generator for motor vehicles

Info

Publication number: GB1576831A
Application number: GB561377A
Authority: GB
Original assignee: Ducellier et Cie
Current assignee: Ducellier et Cie
Priority date: 1976-03-09
Filing date: 1977-02-10
Publication date: 1980-10-15
Also published as: FR2344165A1; FR2344165B1; ES456364A1; IT1082220B; DE2710295A1

Description

(54) A ROTOR FOR AN ELECTRIC GENERATOR FOR MOTOR VEHICLES (71) We, DUCELLIER & CIE, a French Body Corporate of Echat 950, 94024 Creteil Cedex, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention concerns a rotor for an electrical generator, such as an alternator of a motor vehicle, the rotor being of the type including two rotor poles having interdigitated claws, a rotor core fast for rotation with the rotor poles, and a flanged spool between the rotor poles, the spool carrying an excitation winding wound between its flanges.

In such rotors it is not possible to wind the excitation winding on the spool once mounted on the core, since this is prevented by the claws extending across the space between the spool flanges.

It is thus necessary to wind the excitation winding onto the spool supported separately from the rotor and to provide the necessary means for connection between the spool and the rotor poles such as to protect the excitation winding against breakage. Rotors are known in which this connection is effected, for example by producing radial grooves on the internal faces of the rotor poles, the grooves housing corresponding projections formed on the external faces of the spool flanges. However, the work involved in machining the rotor poles to form the grooves adds appreciably to the cost of such a rotor.

The excitation winding must also be protected in the regions of the claws of the rotor poles, and in some rotors the flanges of the spool are sufficiently wide to be turned back when the rotor is assembled. However, these spools are made of soft insulating material and in this case do not have the necessary means of connection between the spool and the rotor poles.

An object of the present invention is to provide a rotor for an electric generator in which these disadvantages are alleviated or avoided.

According to the invention, a rotor for an electric generator comprises two rotor poles having interdigitated claws, a rotor core fast for rotation with the rotor poles, a flanged spool of hard insulating material disposed around the core between the two rotor poles, an excitation winding wound between the spool flanges, axially extending integral projections on the external faces of the spool flanges close to the periphery thereof and respectively arranged to fit between two consecutive claws of the rotor poles so as to make the spool and the rotor poles fast for rotation, and initially radial deformable teeth on the periphery of the two flanges at the circumferential location of the claws, said teeth having been deformed by the claws during assembly so as to lie between the claws and the excitation winding so as effectively to insulate and protect the winding from the claws.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows in section one form of the rotor of the invention, Figure 2 is an axial view of a spool of the rotor of the invention, and Figure 3 shows the spool of Figure 1 in longitudinal section.

Referring to Figure 1, the rotor has in known manner two rotor poles 2 and 3 rigid with a drive shaft 1, a spool 4, and an excitation winding 5 wound between the flanges of the spool 4.

The rotor poles 2 and 3 are each constituted by a disc which has at its central portion one half of a magnetic core and at its periphery claws 2a for the pole 2 and claws 3a for the pole 3, the claws of the respective poles extending parallel to the rotational axis of the rotor in opposite directions.

The spool 4, which is made of a hard plastics material such as polypropylene, has integral projections 7 facing outwardly on the periphery of each of its flanges and corresponding in number to the number of spaces between the claws of the rotor poles 2 and 3. These projections are cup-shaped in order to fit between two adjacent claws and effect the rotational connection of the excitation winding 5 and the rotor poles 2 and 3.

Integral deformable teeth 1 la on one flange of the spool and 1 lb on the other flange, which are triangular and of small thickness, extend radially outwardly of the periphery of the spool flanges and correspond in number to the claws of the rotor poles.

Thus, when the spool is assembled around the core halves between the rotor poles 2 and 3, the teeth 11 a are turned back by the claws 2a and the teeth 1 lb by the claws 3a over the excitation winding 5 wound between the spool flanges and provide insulation and protection of the excitation winding with respect to the claws 2a and 3a.

Two integral pins 9 and 13, preferably cylindrical, are formed in hollows corresponding to the positions of two diametrically opposed projections 7 of one flange of the spool 4, whether or not such projections are present at those positions. These pins 9 and 13 are at least equal in length to the thickness of the rotor pole 3 and have longitudinal slots 9a and 13a into which pass the leads of the excitation winding 5. As seen in the drawings, the pin 9 is used for the passage of the initially wound lead 8 and the pin 13 for the finally ound lead 6.

The fact that these pins 9 and 13 are formed at the normal locations of two projections 7 and fit between the claws of the rotor poles, avoids the drillings usually necessary in the rotor poles for the passage of the leads of the excitation winding.

In order to facilitate the passage of the initially wound lead 8 a recess 10 of depth approximately equal to the thickness of the excitation winding is formed in the inner wall of one of the spool flanges close to the pin 9 and widens out progressively until it reaches the base of the spool 4 in the direction of winding of the excitation winding.

A stud 12 having a constriction is also formed at the location of a projection 7 close to the pin 13 and on the same flange of the spool. The selected projection is that which precedes the pin 13 in the direction of winding of the winding 5 as seen in Figure 2, or is that of the pin 13. The latter case is not shown. The finally wound lead 6 can be wound round the constriction of the stud 12 and held tight so that the spool can be stored without the risk of unwinding whilst awaiting mounting between the rotor poles.

Such a spool thus allows easy mounting of the excitation winding between the rotor poles, since all the elements, rotational connection, passage of the ends of the excitation winding, and immobilisation of these ends are carried out between the claws of the rotor poles, thereby eliminating machining operations such as drilling of holes for the passage of the excitation winding.

Such an embodiment is particularly advantageous in the case of a core split into two half-cores, each rigid with a respective one of the rotor poles, but it can also be used in the case of a rotor having a core independent of the rotor poles.

WHAT WE CLAIM IS: 1. A rotor for an electrical generator, comprising two rotor poles having interdigitated claws, a rotor core fast for rotation with the rotor poles, a flanged spool of hard insulating material disposed around the core between the two rotor poles, an excitation winding wound between the spool flanges, axially extending integral projections on the external faces of the spool flanges close to the periphery thereof and respectively arranged to fit between two consecutive claws of the rotor poles so as to make the spool and the rotor poles fast for rotation, and initially radial deformable teeth on the periphery of the two flanges at the circumferential location of the claws, said teeth having been deformed by the claws during assembly so as to lie between the claws and the excitation winding so as effectively to insulate and protect the winding from the claws.

2. A rotor according to Claim 1 wherein the rotor core is in two portions, each forming part of a respective one of the rotor poles.

3. A rotor according to Claim 1 or Claim 2 wherein slotted pins are provided at two diametrically opposed peripheral locations on one of the spool flanges to guide the initially and finally wound end leads of the excitation winding.

4. A rotor according to Claim 3 wherein a stud is provided at the location of one of the axially extending projections adjacent to the slotted pin which guides the finally wound end lead of the excitation winding, the stud being adapted to retain the finally wound end lead when the spool is awaiting mounting.

5. A rotor according to Claim 3 wherein the flange carrying the slotted pins has a recess formed therein at the location of the initially wound end lead to accommodate said lead passing from the interior to the exterior of the winding.

6. A rotor substantially as hereinbefore described with reference to the accompanying drawings.

7. A flanged spool of hard insulating material adapted to form part of a rotor according to any one of the preceding claims and including axially extending integral projections on the external faces of the flanges close to the periphery thereof and respectively arranged -to fit between the consecutive claws of the rotor poles so as to make the spool and rotor poles fast for rotation, and radial deformable teeth on the periphery of each flange arranged for ~disposition at

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. rotational connection of the excitation winding 5 and the rotor poles 2 and 3. Integral deformable teeth 1 la on one flange of the spool and 1 lb on the other flange, which are triangular and of small thickness, extend radially outwardly of the periphery of the spool flanges and correspond in number to the claws of the rotor poles. Thus, when the spool is assembled around the core halves between the rotor poles 2 and 3, the teeth 11 a are turned back by the claws 2a and the teeth 1 lb by the claws 3a over the excitation winding 5 wound between the spool flanges and provide insulation and protection of the excitation winding with respect to the claws 2a and 3a. Two integral pins 9 and 13, preferably cylindrical, are formed in hollows corresponding to the positions of two diametrically opposed projections 7 of one flange of the spool 4, whether or not such projections are present at those positions. These pins 9 and 13 are at least equal in length to the thickness of the rotor pole 3 and have longitudinal slots 9a and 13a into which pass the leads of the excitation winding 5. As seen in the drawings, the pin 9 is used for the passage of the initially wound lead 8 and the pin 13 for the finally ound lead 6. The fact that these pins 9 and 13 are formed at the normal locations of two projections 7 and fit between the claws of the rotor poles, avoids the drillings usually necessary in the rotor poles for the passage of the leads of the excitation winding. In order to facilitate the passage of the initially wound lead 8 a recess 10 of depth approximately equal to the thickness of the excitation winding is formed in the inner wall of one of the spool flanges close to the pin 9 and widens out progressively until it reaches the base of the spool 4 in the direction of winding of the excitation winding. A stud 12 having a constriction is also formed at the location of a projection 7 close to the pin 13 and on the same flange of the spool. The selected projection is that which precedes the pin 13 in the direction of winding of the winding 5 as seen in Figure 2, or is that of the pin 13. The latter case is not shown. The finally wound lead 6 can be wound round the constriction of the stud 12 and held tight so that the spool can be stored without the risk of unwinding whilst awaiting mounting between the rotor poles. Such a spool thus allows easy mounting of the excitation winding between the rotor poles, since all the elements, rotational connection, passage of the ends of the excitation winding, and immobilisation of these ends are carried out between the claws of the rotor poles, thereby eliminating machining operations such as drilling of holes for the passage of the excitation winding. Such an embodiment is particularly advantageous in the case of a core split into two half-cores, each rigid with a respective one of the rotor poles, but it can also be used in the case of a rotor having a core independent of the rotor poles. WHAT WE CLAIM IS:

1. A rotor for an electrical generator, comprising two rotor poles having interdigitated claws, a rotor core fast for rotation with the rotor poles, a flanged spool of hard insulating material disposed around the core between the two rotor poles, an excitation winding wound between the spool flanges, axially extending integral projections on the external faces of the spool flanges close to the periphery thereof and respectively arranged to fit between two consecutive claws of the rotor poles so as to make the spool and the rotor poles fast for rotation, and initially radial deformable teeth on the periphery of the two flanges at the circumferential location of the claws, said teeth having been deformed by the claws during assembly so as to lie between the claws and the excitation winding so as effectively to insulate and protect the winding from the claws.

locations corresponding to those of the claws in the assembled rotor, and adapted for deformation by the claws upon assembly of the rotor poles so as to lie between the claws and the excitation winding so as effectively to insulate and protect the winding from the claws.

8. A spool according to Claim 7 wherein slotted pins are provided at two diametrically opposed peripheral locations on one of the spool flanges to guide the initially and finally wound end leads of the excitation winding.

9. A spool according to Claim 8 wherein a stud is provided at the location of one of the axially extending projections adjacent to the slotted pin which guides the finally wound end lead of the excitation winding, the stud being adapted to retain the finally wound end lead when the spool is awaiting mounting.

10. A spool according to Claim 8 or Claim 9 wherein the flange carrying the slotted pins has a recess formed therein at the location of the initially wound end lead to accommodate said lead passing from the interior to the exterior of the winding.