GB2091497A - Reinforced collector of the contracted type for a rotating electrical machine - Google Patents

Abstract

Two conductive collars 5, 6 are sandwiched between an insulating sleeve 2 and the slip rings 3, 4 on the shaft 1 of a rotary electric machine. Each collar is constructed so as to allow its diameter to be reduced to a certain extent only. Thus, in a contraction process for fitting the slip rings and collars on the shaft, the contraction of the slip rings is absorbed by the collars, once they have closed, and not by the sleeve. The collars 5, 6 possess lateral wings 5c, 6c which connect them to the induction coil of the machine. Each collar is split, e.g as in Fig. 2. <IMAGE>

Description

SPECIFICATION Reinforced collector of the contracted type for a rotating electrical machine and a process for the manufacture of this This invention relates to the construction of current collectors of rotating electrical machines and, more particularly, of alternators for internal combustion engines.

Patent specification number 79.23971 of this applicant describes an improved process for making a collector of this type, itself designed according to French patent specification No.

2391 577 of the same applicant.

The French patent provides for mounting on the shaft of the electrical machine an insulating ring or sleeve, around which the two rings forming the collector are clamped by magneto-forming. The wires or connections to the induction coil are wedged between each ring and the insulating sleeve so as to eliminate any welding.

The operation of magneto-forming of the rings on the periphery of the insulating sleeve naturally causes high stresses on the latter, so that it is necessary for it to be made of a very resistant material such as a thermosetting material containing a glass fibre filler. Moreover the contraction of the rings causes, in any case, permanent deformation of the insulating sleeve, with the result that the clamping of the connections can be impaired. Heating gradually occurs at this level until the insulator is damaged in such a way that the collector becomes inoperative.

The improvements which are the subject of the present invention are aimed at overcoming this disadvantage and preventing the insulating sleeve from undergoing the contraction forces of the rings.

According to the invention, a conduction collar which can be reduced in diameter is placed between each of the slip rings and the insulating sleeve. Each conductive collar can be split in such a way that the collar can be contracted or the collar can be made with free ends which overlap for the same purpose.

According to a preferred embodiment of the preceding arrangement, each collar is provided with a lateral wing forming the connection between the slip ring and the corresponding terminal of the induction coil of the machine.

The attached drawings, given by way of example, will make it possible to understand better the invention, the characteristics which it possesses and the advantages which it is capable of providing.

In the drawings: Figure 1 is a longitudinal section of one form of a collector of a rotating electrical machine, designed according to the invention.

Figure 2 is an exploded view in perspective, showing the two collars employed to withstand the contraction force of the slip rings.

Figure 3 is a perspective view of such a collar designed according to an alternative form.

Figure 4 illustrates, in perspective and on a larger scale, how the split in the collar of Figure 3 can be shaped so as to grip a single conductor.

Figure 5 is a view similar to that of Figure 2, but illustrating an alternative embodiment.

Figure 6 is a perspective view of a collar used in the alternative form of Figure 5.

Figure 1 illustrates an alternator collector designed according to the invention and intended to be keyed on a shaft bearing the reference numeral 1 and shown by dot-and-dash lines. Such a collector comprises, in the first place, an insulating sleeve 2 forcefitted on the shaft 1, and two slip rings 3 and 4, the periphery of which are contacted by respective brushes (not shown).

According to the invention, a collar, 5 and 6 respectively, is located between each ring 3, 4 and the sleeve 2, so as to absorb the contraction forces applied to the rings 3 and 4 by the magneto-forming.

Figure 2 illustrates the way in which the collars 5 and 6 are formed. It will be noted, first of all, that each of them is split, its split comprising a tenon 5a, 6a penetrating with functional play into a mortise 5b, 6b so as to guide the two ends of the collar which are located opposite one another. It will be seen that each of the collars 5, 6 is provided with a lateral wing, Sc and 6c respectively. At rest, that is to say before assembly, the inside diameter of each of the collars is greater than the outside diameter of the sleeve 2. It will be noted that the collar 6 is also provided, on each of its edges, with three claws.

Three of these, bearing the reference numerals 6d, 6e, 6f, are turned outwards, whilst those of the other edge, bearing the reference numerals 6g, 6h, 6i are directed inwards.

Returning to Figure 1, it may be seen how assembly takes place. The periphery of the sleeve 2 is stepped so as to form a shoulder 2a against which the collar 5 comes to rest. A channel 2b is made in the sleeve so as to ensure passage of the lug Sc in the position in which it is shown in Figure 2. This lug is subsequently bent to make it perpendicular to the longitudinal axis of the sleeve 2 in such a way that said collar is laid flat against the shoulder 2a. The annular ring 3 is then engaged above the collar 5. It will be seen that the sleeve 2 is also provided with a longitudinal orifice 2c in which the wing 6c of the collar 6 passes.

Here also, the wing 6c is bent back perpendicularly to the longitudinal axis of the sleeve in such a way that the claws 6g, 6h, 6i of the collar 6 are brought to bear on a second shoulder 2d provided at the level of the end of the sleeve 2. The ring 4 is subsequently engaged round the collar 6, its edge coming to rest against the claws 6d, 6e, 6f of the collar so as to position the ring 4 at a certain distance from the ring 3.

The assembly is then contracted, preferably by magneto-forming, in such a way that an intimate connection is made between the rings and the collars, whilst protecting the sleeve 2, as indicated above, because the two margins of the slit of the collars butt against one another.

As illustrated in Figure 3, the collars could be simply split to leave a slit 7a of which the lips are made sinuous. Under these conditions, the wing 5c, 6c can be replaced by an insulated conductor 8 which is shown by dot-and-dash lines and the stripped end 8a of which would be engaged between the two lips of the slit 7a at the time of magneto-forming. Moreover, the conductor 8 would also be bent back radially so as to apply the corresponding sleeve against the shoulders 2a, 2d respectively of the sleeve 2, since the second collar is, of course, designed identically to the collar 6, that is to say, it possesses claws. As illustrated in Figure 4, the lips of the slit 7a could have claws 7b, 7c which grip the conductor 8 and two corrugated tenons 7d, 7e brought to bear against said conductor.During magneto-forming, the shoulders 7f on each side of the tenon 7e would be brought to bear against the claws so as to limit the inward deformation of the collar 7.

Figure 5 illustrates another embodiment according to the invention, in which the sleeve 2 is produced by means of two elements 9 and 10 which fit into one another. The periphery of the element 9 is stepped so as to form two shoulders 9a, 9b against which the ring 3 and a collar 11, the function of which is identical to that of the collar 5, are brought to bear respectively. The second element 10 forming the sleeve 2 possesses a skirt 1 Oa which penetrates forcibly into the bore of the element 9. Its periphery is also stepped so as to comprise, first of all, a peripheral border 1 Ob defining a shoulder 1 Oc and then an end portion of smaller diameter which forms, with the rest of the periphery, a shoulder 1 Od.The slip ring 4 bears against the shoulder 1 Oc, whilst the second collar 12 bears against the shoulder 1 Od.

Each of the collars 11, 12 is formed by means of a metal strip which is coiled on itself to make a circle with overlapping ends and which is deformed opposite the free end 1 a of the strip, so as to form a shoulder 1 b having the same height as the thickness of the strip, this shoulder being at a certain distance from the end 1 a in the free position of the collar. The metal strip is constructed to provide a lateral lug 1 c directed perpendicularly to the general plane of the collar 11 (Figure 6).

Thus, once the collars 11, 12 are in piace under the rings 3 and 4, the shrinkage of the latter causes the end 11 a of the collar to butt against its shoulder 1 b in the same way that the slit of the collars 5, 6, 7 closes to withstand the contraction force of the slip rings 3 and 4.

It will be seen that the lug 11 c is slightly offset upwards so that it can engage in an aperture 9c made in the element 9 forming the insulating sleeve, and emerge at the rear of this element and be bent 900 so as to apply the collar against the corresponding shoulder 9b. In the same way, the lug 1 2c of the collar 12 passes through a passage 1 Oe made in the outside of the skirt 1 0a and interacts with the rear of the element 9 once the lug in question has been bent back 900. Thus, on the one hand, the collar 12 is laid flat against the shoulder 1 Od of the element 10, but it also ensures that this element is made integral with the element 9 longitudinally.

In Figures 1 and 5, the ends of the wings Sc and 6c and of the lugs 1 c, 1 2c are coupled to the outputs of the induction coil which have been illustrated by dot-and-dash lines and given reference numerals 13 and 14.

It should be noted that, in the alternative form illustrated in Figure 5, the gap between the slip rings 3 and 4 is filled by the border 1 Ob, so that the machining of the periphery of these rings cannot result in chips being trapped in the space between them, which could, of course, cause electrical faults (short-circuits).

Thus a collector of a rotating machine has been produced, permitting a maximum saving of copper, since there is no transverse cutting of the bush forming the rings 3 and 4, and the insulating sleeve undergoes practically no mechanical force because of the presence of the collars.

Furthermore, the improvements according to the invention make it possible, by reducing the shock and stress of magneto-forming, to use more economical materials for producing the insulating sleeve. Finally, the electrical contact with each slip ring is independent of the possible dimensional variations of the insulator. It goes without saying that the annular surfaces of the collars could be provided with internal and external ribs to ensure their better connection to the insulating sleeve and the slip rings.

Moreover, it must be understood that the preceding description has been given only by way of example and that it in no way limits the scope of the invention which would not be transgressed by replacing the details of execution described by any other equivalents.

Claims (12)

1. Collector of a rotating electrical machine, of the type having an insulating sleeve over which is located a conductive bush contracted onto said sleeve through a conductive clamp forming an internal hoop protecting the insulating sleeve, characterised in that the conductive clamp is made in the form of two collars which can be reduced in diameter placed side by side and each associated with one electrical connection.

2. Collector according to Claim 1 wherein each said connection takes the form of a wire located between two spaced ends of each collar before contraction of the rings.

3. Collector according to either one of Claims 1 or 2, wherein each collar possesses an abutment intended to limit its reduction in diameter.

4. Collector according to Claim 3, wherein each collar consists of a strip of metal bent to form a ring with overlapping ends, a shoulder being formed as an abutment to one free end of the ring, as its diameter is reduced.

5. Collector according to any one of the preceding claims wherein each collar possesses a lateral wing forming the said electrical connection.

6. Collector according to Claim 5, wherein the collar nearest the induction coil of the machine has its wing bent back radially adjacent the end of said sleeve and at the same time the edge of this collar abuts a shoulder on the sleeve.

7. Collector according to any one of the preceding claims wherein the two edges of the collar remote from the induction coil of the machine are provided with radial claws bent back outwards as regards the first edge and inwards as regards the second, in such a way that said collar lies flat against a shoulder of the end annular face of the insulating sleeve and that it forms an axial abutment for the corresponding ring of the collector.

8. Collector according to any one of the preceding claims wherein the insulating sleeve is made of two elements which fit into the one another and which possess means for the axial retention of the collars and the rings.

9. Collector according to Claim 8, wherein the collar located nearest the induction coil of the machine is accommodated in a recess provided on the periphery of the corresponding element, the second element of the insulating sleeve possessing a border which forms a spacer between the two rings, the second collar bearing against a shoulder of the corresponding element.

10. Collector according to Claim 8 or Claim 9 wherein the first element of the insulating sleeve possesses two shoulders, against which bear one ring and collar, whilst the second element is provided with two shoulders for the other ring and collar.

11. Collector according to any one of the preceding claims wherein the slip rings are contracted by magneto-striction.

12. Collector of a rotating electrical machine substantially as described with reference to Figs. 1 and 2 or Fig. 5 of the accompanying drawings with or without the modifications shown in any of Figs. 3, 4 or 6.