AU627487B2

AU627487B2 - Slip ring arrangement

Info

Publication number: AU627487B2
Application number: AU40410/89A
Authority: AU
Inventors: Henning Fasterding; Karl-Heinz Koplin
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1988-11-12
Filing date: 1989-08-01
Publication date: 1992-08-27
Anticipated expiration: 2009-08-01
Also published as: DE3838436A1; ES2017334A6; AU4041089A; EP0444044B1; DE3838436C2; EP0444044A1; JP2831416B2; DE58906657D1; WO1990005395A1; JPH04501499A

Description

I

OP F E 28/05/90 APPLN. ID 40410 89 A TE 05/07/90 PCT NUMBER PCT/DE89/00506 INTERNATI( IE INTERNATIONALE ZUSAMMENARBEIT AUF DEM GEBIET DES PATENTWESENS (PCT) (51) Internationale Patentklassifikation 5 (11) Internationale Veriffentlichungsn -er: WO 90/05395 HOI1R 39/14, HO2K 13/00 Al (43) Internationales Verdffentlichungsdatum: 17. Mai 1990 (17.05.90) (21) Internationales Aktenzeichen: PCT/DE89/00506 Veriffentlicht (22) Internationales Anmeldedatum: 1. August 1989 (01.08.89) Mit internationalem Recherchenbericht.

Prioritatsdaten: P 38 38 436.1 12. November 1988 (12.11.88) DE (71) Anmelder (fir alle Bestimmungsstaaten ausser US): RO- BERT BOSCH GMBH [DE/DE]; Postfach 10 60 50, D- 7000 Stuttgart 10 (DE).

(72) Erfinder; und Erfinder/Anmelder (nur fir US) KOPLIN, Karl-Heinz [DE/DE]; FrankenstraBe 26, D-7141 Schwieberdingen FASTERDING, Henning [DE/DE]; Behringweg D-7145 Markgr6ningen (DE).

(81) Bestimmungsstaaten: AT (europdisches Patent), AU, BE (europiisches Patent), CH (europtisches Patent), DE (europtiisches Patent), FR (europiisches Patent), GB (europaisches Patent), IT (europiisches Patent), JP, LU (europiisches Patent), NL (europfiisches Patent), SE (europiisches Patent), US.

(54)Title: SLIP RING ARRANGEMENT (54) Bezeichnung: SCHLEIFRINGANORDNUNG (57) AbstractM In a slip ring arrangement for the rotor of an electrical three-phase current ogenerator for motor vehicles or the like, it is proposed to link the end of the slip 12 18 s ring holder to the rotor or armature spindle by pushing it over a smaller-diameter journal of the rotor spindle and securing it axially by making it a force fit or, for example, by means of splines, where plastic-coated busbars run from the slip rings in grooves in the armature spindle beneath the ball-bearing and their broadened ends are soldered to the excitation winding connecting wires. Alternatively, the slip 1 ring holder may be secured to the journal or a bearing neck pressed into the end of the rotor spindle by a clip, while prestressed leaf springs ensure axial clearance. In both cases, the flange of the slip ring holder pushed over the armature spindle and the fan fitted at the same place may be in one piece, whereby the metal parts of the fan are laid in the extrusion or compression mould for making the plastic bearing housing together with slip rings and busbars, and the housing is formed around them.

(57) Zusammenfassung

I

Bei einer Schleifringanordnung fir den Rotor eines elektrischen Drehstromgenerators fir Kraftfahrzeuge o.dgl. wird vorgeschlagen, den Schleifringhalter dadurch endseitig mit der Rotor- oder Lluferwelle zu verbinden, dag dieser auf einen Zapfen der Rotorwelle mit geringerem Durchmesser aufgeschoben und durch PreRsitz, auch z.B. mittels [alterillen axial gesichert wird, wobei von den Schleifringen ausgehende kunststoffummantelte Stromschienen in Nuten der Lduferwelle unter dem Kugellager hindurch laufen und mit verbreiterten Enden mit den AnschluIdrlhten der Erregerwicklung verschweist werden. Alternativ wird der Schleifringhalter auf dem Zapfen oder einem in die Rotorwelle endseitig eingepreten Lagerbolzen dutch eine Klipsbefestigung verankert, wobei zur Sicherung einer axialen Spielfreiheit vorgespannte Federzungen vorgesehen sind. In beiden Fillen kinnen der weiter aul die Liuferwelle aufgeschobene Flansch des Schleifringhalters und der sich an der gleichen Stelle befindende zugewandte Lafter aus einem StOick bestehen, wobei die Liftermetallteile mit Schleifringen und Stromschienen in die Spritzoder Pregform far die Herstellung des Kunststofftrigergehauses mit eingelegt und umgespritzt bzw. umgepregt werden.

A

rni-

I

f Slip Ring Arrangement

I

4 4 State of Technology The invention relates to a slip ring arrangement.

In a known slip ring arrangement of this type (DE-OS 35 10 489), there is an axial hole at one erd of the rotor shaft, directed towards the interior, which is used to locate the slip ring support shaft. The slip ring support shaft is part of a slip ring unit, consisting of two slip rings, with electrical conductors leading from these and connected with the rotor field coil, and a body of insulating material which connects these parts with each other and accommodates them. This results in the .10 one-piece character of the slip ring unit, which is fixed to the rotor shaft by virtue of the fact that the slip ring support shaft is pushed with an interference fit into the axial bore of the rotor shaft.

io o o• 3 o•* o *oeo i :i 1 i 2 A noticeable two-part make-up thus results from the fact that a first part-body of insulating material gives bearing support to the slip rings and that bridging legs extend from the same insulating material, inside of which the connecting leads are routed from the slip rings as far as a cover ring which is connected with the slip ring support as a single piece with these bridging legs. The bridging legs with the connecting leads located within them rest in grooves at the end of the rotor shaft and are passed underneath the ball race located at this end of the rotor shaft and connected with the rotor winding. This enables the slip ring/brush area to be arranged externally, as seen from the electrical machine, that is behind the ball race; but an additional slip ring support shaft is required for the slip ring unit, which is pushed into the rotor oeoeI S shaft axial bore, without the slip ring unit being apparently oo secured axially on the rotor shaft and unaffected by corresponding warming. The structure of the known slip ring bearing is more complicated no details are given on the special routing and formation of the connecting leads between the slip rings and the exciter winding.

V Io4 •oooo 'Jl -3- A slip ring arrangement is known furthermore from the French patent application with the publication number 2 593 976, in which, comparable with the embodiment corresponding to the earlier mentioned DE-OS 35 10 489, a central pin leads from the slip ring support, and carried within this pin are the electrical connection leads, the pin itself is inserted in a front face axial bore of the rotor shaft. Electrical feed leads are then routed through transverse bores in the rotor shaft, to the connections of the exciter winding. In this slip ring arrangement, the slip ring support is again on the other side of the ball race.

The invention is based on the requirement to provide a simply structured and therefore economical and easily assembled slip ring arrangement in a design amenable to automation, in which it is ensured that the slip ring holder will be held in a radially o o ee ~and axially unaffectable position on the rotor shaft, even in tfol the event of vibrations or thermal stresses.

r:" oeS 1o 3..

oo; o o r -4- Advantages of the Invention According to the invention there is provided slip ring arrangement for the rotor of an electrical machine, in particular of an alternator for motor vehicles, railways, buses, and the like having a rotor shaft supporting the rotor and a slip ring holder located on its end, with slip rings and connecting leads which connect said slip rings with the exciter winding of the rotor, said slip rings and the connecting leads being embedded in a one-piece plastics support part, which is fixed on a spigot of smaller diameter, arranged on the end of the rotor shaft, said connecting leads emerge with their ends remote from the slip rings, in front of an end disc from 10 said plastics support part, said end disc being made in one piece with said plastics support part and said slip ring holder is pushed onto said spigot.

r i5 a The invention also provides slip ring arrangement for the rotor of an electrical machine, in particular of an alternator for motor vehicles, railways, buses, and the like having with a rotor shaft supporting the rotor and a slip ring holder with slip rings located on its end, and connecting leads which connect these with the exciter winding of the rotor, said slip rings and said connecting leads being embedded in a plastics support part fixed on a tapered spigot of the rotor shaft, said slip ring holder being pushed onto said spigot and held by a circlip.

The invention has the advantage that a secure radial and axial seating of the entire slip ring arrangement is achieved, combining simple assembly with good welding access and hence a corresponding reduction of the reject quota.

In a first, preferred embodiment of the invention, the excellent axial securing is achieved by a single-piece spigot of the rotor shaft extending into the area of the slip rings, and there, due to pressing, e.g. also via longitudinally and transversely extending holding grooves, it secures the actual slip ring support, with the electrical connecting conductors, which are configured as flat conductor rails, being arranged as supplements in plastic sheathed bridges between the slip ring support and the end disc and which are axially secured by the ball race, which results in cc- tl c~C~ an appropriate axial securing of the slip ring support area via the connecting bridges.

In a preferred embodiment, an axial securing is ensured by virtue of the positively locking rear engagement of interlocking tongues, which extend from the area of the slip ring support. Again in this embodiment, a bolt, which is pressed firmly and securely into the rotor shaft, initially without regard to the slip ring arrangement, is guided right into the area of the slip rings. Complete freedom of play is ensured by spring tongues which are arranged at the end of the slip ring support and which press against the front face of the bolt.

'JE0 With both embodiments, therefore, a design is given which is particularly suited :i to automation.

~A particular advantage of the preferred embodiments is the large area welding of the bent-off conductor rails as electrical connection leads between the slip rings and the exciter winding of the rotor on the inner face of the slip rings, through 15 resistance welding, and the all-round embedding of the flat conductor rails in the plastic material of the pressed form of the support housing.

A further advantage is that the end plate of the slip ring holder can be made as one piece with the side fan or ventilator, with the metal parts for the fan also being embedded in the plastic part of the end plate and formed in by injection moulding.

Drawing Embodiments of the invention are shown in the drawing and are i1 i Fi 6 explained in more detail below, vis:- Fig. 1 a large drawing, illustrating the interconnections, shows in sectional view the allocation and assembly pf the slip ring arrangement with the shown rotor of an a.c.

generator, the other parts of which have been omitted; Fig. 2 the slip ring arrangement placed on the rotor shaft end area, shown in sectional view in a first embodiment example, and Fig. 3 the presentation of fig. 2 in a view from the left, while Fig. 4 shows the same slip ring arrangement as fig. 2, but turned through 90', in sectional view; Fig. 5 shows the embodiment of figs. 2, 3, and 4, in plan view; Figs. 6 7 show the bent electrical conductor rails, partly in o ~sectional view, which are connected on the inside to the slip rings by resistance welding, whereas Fig. 8 shows the conductor rail fixing in a front view; oe Figs. 9, 10 and 11 are sectional and top views of figures 2, 4, o- ~and 5, in corresponding order, of a preferred embodiment r of a slip ring arrangement, while Fig. 12 shows the slip ring bearing arrangement of fig. 11 in a view from the side showing the spring tongues towards the axial freedom from play.

*A N ii- i ce me m uescription or the Embodiments In fig. 1, which is intended for a clearer understanding of the invention, a claw pole rotor 10 of an electrical machine, namely an alternator for motor vehicles and the like is shown, with the rotor shaft 12 providing the bearing for the electrical exciter winding 13, which is fed with the required exciter current by the two slip rings 14a, 14b via electrical connection leads Fan blades on both sides are designated 16a and 16b; the sided ball race 17 is between the slip rings 14a, 14b and the electrical connection leads 15a and 15b which lead to the exciter winding 13, so that the conductor rails 15a', which are part of the electrical connection leads, are routed through underneath the ball race 17. Fastened to their widened S: ends 18 are the connection wires of the exciter winding, usually spot welded, with the slip ring assembly and the fan, as shown in fig. 1, being separate parts.

The two slip rings 14a, 14b, and the conductor rails 15a', I are part of a one-piece slip ring holder, such as shown in figures 2, 4, and 5, and 9, 10, and 11, respectively, and a designated 20 and 20', respectively (figs. 9, 10, and 11). The slip ring holder 20, 20', as best shown by figures 5 and 11 consists of two partial areas, namely support 21, 21'(fig. 11) I j e j for the slip rings, and an end plate 22, 22, connected as a single piece with this support 21, 21', which is connected, axially offset, with the support 21, 21', via two diametrically opposed connecting bridges 23a, 23b. These connecting bridges 8 contain the plastic sheathed electrical conductor rails which are shown in figures 6 and 7 as bent flat bands of an appropriate, good electrically conductive metal, on'a larger scale.

Figures 6 and 7 with fig. 8 make it clear, that a shorter conductor rail 15b' and a longer conductor rail 15a' are provided for the connection of the outer slip ring 14b which is more distant from the exciter winding, and the end plate, whereby the flat metal bands of the two conductor rails, in their initial punched form, are bent off in accordance with the requirements, and fixed with their one end at 24 at the interior wall of the slip ring concerned, by a wider tab 25 at the end, preferably by resistance welding to the slip ring. In the central area, the flat bands of the conductor rails then extend through the connecting bridges 23a, 23b, and emerge with their widened ends 18 (see fig. 1) from the widened hub area 22a of the end plate body, to the outside.

oe The whole structure of such a slip ring holder is as a single eooo piece, with the two metal parts of the slip rings shown in figs.

6 and 7, and the conductor rails (already connected with each other) placed either in an appropriate injection mould for the 00..

e manufacture of the injection moulded plastic part for the slip ring holder, or using a suitable insulating plastic, adopt the *o final form of the slip ring holder shown in the figures.

0e 0 *a L p t 00..tf -9- Only the outer cylinder faces of the slip rings 14a, 14b, and the widened ends 18 of the connecting leads 15a', 15b' are not covered by the plastic material.

Two- forms of embodiment are obtained for the connection of the slip ring holder and/or for attaching to the rotor shaft end on this side, whereby in accordance with figures 2 and 5 as the preferred embodiments, the procedure is such that a machined spigot 12a, i.e. one which is preferably connected with the rotor shaft 12 as one piece, is pushed as an interference fit into the inner opening or bore 26 of the supporting part 21 for the.slip rings, and is axially anchored and fixed via suitable transverse holding grooves A and/or longitudinal grooves 27 (see figs. 4 and A front face 27 of the support part 21 l2Jo then abuts on the shoulder/ S in the transition between the shaft diameter and the spigot 12a, with the larger diameter hub 22a of the end plate 22 being pushed further onto the rotor shaft 12. The connecting bridges 23a, 23b, then extend in longitudinal grooves 21 of the rotor shaft, from which they emerge, as shown at 28qin fig. 2, in the transition towards the rear flange 22b of the end plate 22. This flange 22b of the slip ring holder 20, 20' then at the same time searves for the o: ~centering of the fan 16b, or, the flange can form one piece with the fan, in accordance with a preferred embodiment of this invention, whereby from the beginning, the slip ring holder with its support housing of insulating material is made together with the fan. In this embodiment, the metal parts of the fan can then also be placed in the injection mouia, rogezner with the parts (slip rings and conductor rails) shown in figures 6 and 7, and moulded in or pressed in.

In this way, a short bodied compact generator is obtained with secure seating of the slip ring holder on the fan shaft end, because due to the ball race 17 being pushed with its inner race fully to the stop against the hub front walling 22c, the whole structure is held radially and axially immovable in its end mounted location, in accordance with fig. 1.

The second embodiment of a slip ring holder shown in figures 9 to 12 differs from the previously explained embodiment only in the type of its fixing on the rotor shaft end. In this otherwise identical embodiment, a bolt 31 is pressed into an axial bore 30 on the front face of the rotor shaft 12', initially without paying any attention to the slip ring holder and its plastic top structure. The bolt thus sits securely and immovably as a press fit in the rotor shaft end; an alternative method being to replace the bolt form, which is yet to be S. explained in more detail, by a machined-on spigot, as in the previous embodiment example.

Adjacent to the end face wall 32 on the rotor shaft 12', but at the specified distance to the same, the bolt has a shoulder 33, which is embraced from the rear by locking pieces 34 with transverse noses 34a(see figures 10 and 11) which extend o r *ee *i j lo m o Tool I I_ -11from the support part 21'. The bolt extends from -cne snou-uer in the drawing of figures 10 and 11 further to the right with a different or with the same diameter, continuing virtually to the end of the support part 21'.

At this point, as is best seen in the top view of fig. 12, the support part 21' has springy tongues 35 which extend from the perimeter inwards and point axially inwards with a certain amount of preloading, these tongues will be forced back when the locking pieces 34 have embraced the shoulder 33 on the bolt from behind, i.e. pressed axially outwards to such an extent that, starting from these springy tongues, a constant axial preloading and hence a secure seating of the support part 21' and thus of the entire slip ring holder 20' on the shaft end and on the bolt 31, respectively, will result. Here again, the end disc 22' is pushed further onto the shaft with the enlarged diameter, with the connecting bridges 23a, 23b proceeding in longitudinal grooves 27 of the shaft end, and in this latter feature this embodiment example does not differ at all from the embodiment described in the first place.

If the bolt 31 is formed by a machined-on spigot of the rotor shaft end, it must be ensured that the shoulder 33 is formed in the same way in order that by the embracement of the locking pieces 34 from the rear, axial securing of the slip ring holder o 1 I 12 on the rotor shaft end, in addition to the stop action provided by the ball race, will result.

It is of advantage that the flange of the slip ring assembly in the shown embodiments, in addition to the facility for fan centering and fixing, serves as a stop for the ball race mounting.

Finally, as shown in fig. 1, two holding cams 18a, 18b are provided for the electrical lead connections of the exciter winding on the slip ring assembly flange, these cams are used as strain relief for the electrical connections. They also position the electrical leads during the resistance welding.

All features described in the subsequent claims and presented in the drawing can be of inventive significance both as individual features and in any combination with each other.

"V 5 "7 cc 4 j

I.I

I

Claims

1. Slip ring arrangement for the rotor of an electrical machine, in particular of an alternator for motor vehicles, railways, buses, and the like having a rotor shaft supporting the rotor and a slip ring holder located on its end, with slip rings and connecting leads which connect said slip rings with the exciter winding of the rotor, said slip rings and the connecting leads being embedded in a one-piece plastics support part, which is fixed on a spigot of smaller diameter, arranged on the end of the rotor shaft, said connecting leads emerge with their ends remote from the slip rings, in front of an end disc from said plastics support part, said end disc being made in one piece with said plastics support part and said slip ring holder is pushed onto said spigot.

2. Slip ring arrangement for the rotor of an electrical machine, in particular of an alternator for motor vehicles, railways, buses, and the like having with a rotor shaft supporting the rotor and a slip ring holder with slip rings located on its end, and connecting leads which connect these with the exciter winding of the rotor, said slip rings and said connecting leads being embedded in a plastics ooo..: support part fixed on a tapered spigot of the rotor shaft, said slip ring holder being pushed onto said spigot and held by a circlip.

3. Slip ring arrangement in accordance with claim 2, wherein said spigot 20 has a ring-shaped projection which forms a shoulder at a distance from the rotor shaft end, said ring-shaped projection being gripped by locking hooks on the plastics support part for the slip rings.

4. Slip ring arrangement in accordance with claim 3, wherein springy tongues are provided which, after engagement of the locking hooks of the slip ring holder rest against the end of said spigot to provide an axial zero backlash condition. Slip ring arrangement in accordance with claim 4, wherein said springy tongues at the remote end of the support part of the slip ring holder project radially inwards and at the same time axially inward directed lobes on the support part are formed, which after engagement with said shoulder are pressed axially A outwards to such an extent that a constant pressure results which axially fixes the slip ring holder.

CN I' 0Y BI -14- 14 V. 0.0: 0.. 00.0 0:0.

6. Slip ring arrangement in accordance with claim 1, wherein said spigot is machined on the rotor shaft which projects up to a rear area of the said plastics support part has longitudinal and/or transverse holding grooves to radially secure the press-fit located support part of the slip ring holder.

7. Slip ring arrangement in accordance with any one of claims 1 to 6, wherein said electrical connection leads are formed by flat conductor rails which with their one end are fixed to the inner face of a respective slip ring.

8. Slip ring arrangement in accordance with claim 7, wherein said conductor rails are metallic band forms produced by punching and are appropriately bent off, and which emerge with an expanded end part in front of a radial flange of said end disc from said plastics support part for the connection :o with electrical lead connections of the exciter winding.

9. Slip ring arrangement in accordance with any one of claims 1 to 8, S wherein a fan is arranged on the side of the slip ring holder and is centered by a 1 5 flange which extends from the end plate of the slip ring holder. Slip ring arrangement in accordance with any one of claims 1 to 8, S wherein said slip ring holder in the area of the end plate and a fan consist of one piece.

S

11. Slip ring arrangement in accordance with claim 10, wherein parts of said fan formed of metal are encased together with the slip rings and the conductor S rails, having the plastic material of the plastics support part injection moulded or pressed arou: c them.

12. Slip ring arrangement in accordance with claim 3, wherein the spigot at the rotor shaft end is formed by a bearing bolt pressed into the rotor shaft.

13. Slip ring arrangement substantially as hereinbefore described with reference to the accompanying drawings. DATED this 10th day of June ROBERT BOSCH GmbH By their Patent Attorneys: CALLINAN LAWRIE

1992.