GB2046027A

GB2046027A - A current transfer arrangement or commutators

Info

Publication number: GB2046027A
Application number: GB7926408A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-07-31
Filing date: 1979-07-30
Publication date: 1980-11-05
Also published as: JPS6359510B2; DE2930915A1; FR2432784B1; JPS5559673A; GB2046027B; FI792384A; FR2432784A1; CH665310A5

Abstract

A current transfer arrangement for commutators and slip rings of rotating electric machines, comprises a rotating part 7, as shown flexible, which extends over 360 DEG and rolls over the commutator 8 or slip ring, there being provided a stationary conducting lead-in device 4, as shown rigid, having two or more spaced fingers 1, 2, 3, which act on the rotating part 7 and cause this to exert a pressure on the commutator or slip ring. The part 7 may consist of spring steel, or it may be rigid whereupon the part 4 is flexible. The commutator segments may be oblique or have a stepped shape (Figs. 3 and 4 not shown). The member 7 may have teeth engaging teeth on a ring on the commutator to effect positive drive (Figs. 5 and 6 not shown). The fingers 1, 2, 3, may act on the part 7 through intermediate rollers, and the part 7 may be an extensive band. <IMAGE>

Description

SPECIFICATION A current contacting arrangement.

The subject of the invention is a current contacting arrangement, in particular for communicators and slip rings, in which arrangement a rotating part extending over 3600, preferably flexible and rolling over the commutator, resp. slip ring, is present.

Such current contacting arrangements are known for instance out of the USA patent 3 341 726 and the German patent application DT OS 23 27 793 laid open for public inspection.

Whilst the first of these is applicable only to fractional motors and that with very considerable reduction of power, both of them have the disadvantage of being expensive.

The purpose of the invention is therefore to give a current contacting arrangement of simple design and suitable with tolerable power loss for all applications.

According to the invention this is obtained by providing a preferably stationary arrangement which has at least two rounded-off surfaces arranged inside or/and outside the rotating part and acting upon the latter with a force and this preferably within the contact range with the commutator or similar appliance and preferably in the direction towards the commutator or similar appliance, by which means the rotating part is held, the arrangements being loosely connected with the rotating part and not firmly attached to it.

Further details of the invention are disclosed in the embodiment examples explained by the drawings. The latter show on Fig. 1 in cross section and on Fig. 2 in top view a contacting arrangement according to the invention.

on Figs. 3 and 4 designs of a commutator according to the invention.

on Figs. 5 and 6 further designs of contacting arrangements.

The essentially rigidly designed hand-shaped, for instance metallic, device 4 is (Fig. 2) fixed by screws 5 and 6 at a suitable place, for instance at the not shown brush holder plate, and has three also essentially rigid fingers 1, 2, 3, the spheric ends of which (Fig. 1 showing a cross section along the line A-A of Fig. 2) press upon the rotating part 7 consisting of spring steel. By this the endless rotating part 7 is held and in addition a certain contact area is obtained with the commutator 8. It is expedient to apply for the rotating part 7 a guide consisting of the ring 9 fixed at the commutator 8 and the disc 10 arranged at the side of the commutator (Fig. 6) between which the rotating part rolls off and this has a vibration damping effect.

When the commutator 8 rotates (in the direction of the arrow) the rotating part is taken with it whilst being held by the fingers 1-3 and the current flow proceeds over the stationary circuitclosing screws 5, 6, the stationary device 4, its fingers 1-3 and then over the rotating part 7 to the individual segments of the commutator 8.

The device 4 can have fewer fingers (for instance be without the finger 1 'arranged outside the rotating part) or have more than three fingers.

The rotating part 7 can also be designed rigidly and then the device 4 would have to be flexible.

With the usual shape of the commutator segments the device 4 must exercize a relatively great force upon the rotating part 7, i.e. the rotating part has to be "deformed" in order to obtain the required coverage. It is therefore proposed to arrange the boundaries of the segments in the range of the gaps between them not as usual, in the axial direction, but at an angle to the axial direction of the commutator, as shown on Fig. 3 (the dotted line shows, as also on Fig. 4, the axial direction of the commutator) where a few segments according to the invention can be seen in top view.Still better is the design of the segments 11 shown on Fig. 4; with this a rapid and neat switching by the rotating part 7 is obtained because at the start and the end of the contact between the rotating part and a segment a large longitudinal contact surface is available, contrary to the design according to Fig. 3 where at the start and the end of the touching the contact surface is punctiform. In this way it is also possible to obtain the required coverage with a line-shaped contact surface between the rotating part and the commutator, i.e. with a small pressure of the rotating part. Such shapes of commutator segments are also suitable for other contacting arrangements, for instance those according to the German patent application DT-OS 23 27 793 laid open for public inspection.

It is of advantage to border the rotating part 7 with friction rings which roll off the commutator whilst increasing the friction. According to Fig. 5 the rotating part 7 has a toothed rim and correspondingly the ring 9 is in this case a toothed ring and the perforated disc 10 a toothed wheel, each having at least one tooth, i.e. the teeth of the rotating part, for which the saw tooth form is best suitable, engage with the teeth of the parts 9 and 10, both of which are best made of plastics. In this way a non-slipping drive of the rotating part is obtained.In this it should be noted that, the diameters of the rotating part and of the commutator are of unmatched proportions to ensure that the rotating part surface roughened by the commutation is distributed over its entire circumference, i.e. that the switching should not 'always occur exactly at the same places. 12 designates the motor shaft.

In addition to the rigid fingers 1-3 it is also possible to arrange flexible fingers, for instance in the area of the contact surface between the rotating part and the commutator. It is to advantage to make such fingers in one piece with the device 4. Rolling bodies can be arranged between the fingers 1-3 and the rotating part 7, in which case the ends would be curved oppositely to what is shown on Fig. 1 and the rolling bodies would be held in these curvings whilst rolling over the rotating part. It is also possible instead of the guides 9 and 10 or additionally to them to provide the device 4 with flat extensions running in the radial direction of the rotating part, such extensions guiding the rotating part (better).

Flexible fingers 1-3, which continue to exercize the same pressure when their contact surfaces are subject to natural wear, are of advantage even in the case of the flexible rotating part when a very long service life is required. Instead of a rotating part 7, i.e. a hollow cylinder or a ring, a different kind of part can be used, for instance a band (several decimetres long).

In the absence of a friction drive or a toothed drive for the rotating part 7 the latter is periodically carried forward through its roughened by sparks surface by the segment edges and continues to roll periodically; it thus has the nature of an endless metal brush, but here the entire circumference of the rotating part is available and not only the small area of a metal brush. If a frictional or toothed drive is available, then the gaps between the segments can be carried up to the surface level.

It can easily be seen that the purpose set for the invention is fulfilled by the design in accordance with the invention of the rotating part 7 with possibly more than only one device 4 in rigid or flexible form, with possibly a frictional or toothed drive and in addition possibly with a form of commutator segments in accordance with the invention.

Claims

1. A current contacting arrangement, in particular for commutators and slip rings of rotating electric machines, for instance motors, or for measuring and regulating equipment, in which arrangement a for instance flexible, rotating part extends over 3600 and rolls over the commutator or over a similar appliance, there being provided at least one preferably stationarily arranged device (4), of which two or more sections (fingers 1, 2 and 3), preferably extending over a definite angular range, are arranged inside and/or outside the rotating part (7) and exercise a force upon the latter, preferably within the range of contact with the commutator or a similar appliance and thus excercise a pressure on the commutator or similar appliance, such sections having preferably rounded-off surfaces and the device (4) being loosely connected with the rotating part (7) and not firmly attached to it.

2. An arrangement as claimed in claim 1, characterised by the force on the rotating part (7) being essentially or entirely exercised in the range of that half of the rotating part (7) which is turned towards the commutator or similar appliance.

3. An arrangement as claimed in claim 1 or/and 2, characterised by no or no essential force being exercised on the rotating part (7) within the range of the side borders of this rotating part as viewed from the commutator or similar applicance.

4. An arrangement as claimed in claims 1, 2, or/and 3, characterised by the rotating part (7) being essentially circular.

5. An arrangement as claimed in claims 1, 2, 3 or/and 4, characterised by the device (4) producing a gliding or/and rolling contact with the rotating part (7).

6. An arrangement as claimed in claims 1, 2, 3, 4 or/and 5, characterised by the rotating part being made flexible, due to which it is modified in the contact range with the commutator (8) at least during the touching of it and because of this touching, i.e. the rotating part (7) touches the commutator or similar appliance over more or less than one angular degree of the rotating part (7) depending on the pressure force, the device (4) being rigid at least essentially.

7. An arrangement as claimed in claims 1, 2, 3, 4, 5 or/and 6, characterised by boundaries (9, 10) being arranged for the rotating part (7) which boundaries are fixed to the commutator (8) or similar appliance and run in its circumferential direction, it being possible for such boundaries to be also toothed and engage with the on both sides toothed border of the rotating part (7).

8. An arrangement as claimed in claims 1, 2, 3, 4, 5, 6 or/and 7, characterised by the device (4) being flat, having fingers (1, 2, 3) arranged inside or/and outside the rotating part (7) and acting upon the latter.

9. An arrangement in accordance with one of the claims 1-8 of a known kind, for instance in accordance with the Austrian patent specification 284 260, characterised by the commutator segments in their angled end parts (i.e. as viewed in the direction of rotation at the begining and the end of a segment) running in a certain range at first approximately in the axial direction of the commutator, i.e. two adjoining and insulated from each other segments intermesh over a certain angular distance on the commutator circumference, the width of the distance between the segment being smaller than the said angular distance.