DE1917873U - BRUSH ARRANGEMENT FOR DC SMALL MOTORS. - Google Patents

Description

^ 241484 * 11.5.65

PATENT LAWYERS

DIPL-ING. CURT WALLACH

DIPL-ING. GONTHER KOCH

DR. TINO HAIBACH

8 MUNICH 2, the '™ ^3f ™haben

OUR MARK: 6899 ~

Konrad BIhI, Factory for Precision Mechanics, Dietingen Krs. Rottweil. Brush arrangement for DC miniature motors

The invention relates to a brush arrangement for DC miniature motors with two brushes designed as leaf springs, which rest tangentially on the collector in a resilient manner. These contact brushes, designed as leaf springs and made, for example, of leather bronze, have the advantage of being considerably cheaper than conventional carbon brushes loaded by helical springs, because the complicated brush guides are no longer necessary. On the other hand, known direct current miniature motors with contact brushes made of leather sheet often have the disadvantage of a relatively low degree of efficiency, which is essentially due to the contact resistance between the brush and the collector. In the known motors namely the setting of the optimal Bürstenanpreßdrucks and the current decrease caused considerable difficulties because the brushes were rigidly carried by a bearing bracket in the housing, and due to unavoidable tolerances, the brushes held at a predetermined distance from each other in a fixed position on the bridge in the installed state often were asymmetrical to the motor axis, so that the one brush too high a pressure with the consequence of an unfavorable high mechanical resistance and

the other brush too little contact pressure with the result subject to an unfavorably high electrical contact resistance was.

In addition, the assembly required for the well-known miniature motors of the type mentioned still requires a relatively high level of effort, because the brush holder had to be inserted separately into the motor housing.

The aim of the invention is to avoid these disadvantages and a To create brush arrangement that with optimal, constant burst enanpreßdruck ensures simple and cheap assembly.

For this purpose, a brush arrangement of the type mentioned is designed according to the invention in such a way that the The motor housing, which encloses the collector and is made of insulating plastic, has a recess through which the two Brush springs protrude, the outside bent in opposite directions and outside in their bent part are fixed on the G-e & outer wall. The brush storage forms here accordingly a fixed part of the motor housing, the opposite the motor shaft and accordingly also with respect to the collector is set with the lowest tolerances. So you need all you have to do is ensure that all the brush springs have the same shape in order to ensure that they fit the collector rest with the same predetermined preload, the bending of the bearing ends is to be made so that they are the same

Have the same shape as the outer wall of the housing on which they are to rest come.

A particularly simple and reliable storage is obtained if the housing is equipped with a flattening at the point of the extension serving for the burst feedthrough, which is symmetrical to the central plane passing through the extension and the Hotor. The bends of the brush springs are also to be made flat so that the angular position of the spring leg ₁ which comes into contact with the collector or its spring preload is securely fixed.

The position of the leather in relation to the said midplane can be determined once in the simplest way by the fact that the radius of curvature rests against the side boundaries of the recess, and in addition, this distance can be determined by holes that are previously made in the support surface of the Housing and the bent spring leg are attached, through which a tubular rivet is inserted, which is a reliable and ensures easy fixing of the outer spring section on the housing. A particularly favorable alignment of the brush springs results when the bearing for the motor shaft is formed in one piece with the housing section that contains the bearing surfaces for the bent thighs. Then namely due to the small distance between the shaft bearing and the collector, the predetermined mutual Position between brush and collector or compliance with the predetermined pre-tension is guaranteed.

Such a brush arrangement is useful, for example, for DC miniature motors, which are used to periodically wind up a mechanical energy store in clocks. The periodic switching the motor can be easily removed by removing the brush be accomplished. when the with the collector in contact coming spring leg of a brush is extended and protrudes through a housing opening to the outside. At this A pin can then protrude from the housing attack that the brush against its spring preload of lifts off the collector and thus interrupts the circuit. Further complicated and expensive switches can then be dispensed with will.

To further improve the electrical current supply between According to the invention, the collector and brush are also provided, the leg coming into contact with the collector to be provided with at least two pronounced ribs running in the longitudinal direction. This will put two at a distance from each other Lying defined contact points created, the spring action balancing out so that both contact points one substantially have the same contact pressure. The cross-section of these hips can expediently be U-shaped, where the transverse leg of the U is the contact point or the Koircaktflache forms.

Further advantages and details of the invention emerge from the following description of an embodiment example the drawing. In the drawing show:

Fig. 1 is a side view of one with the brush arrangement according to the invention equipped direct current miniature motor, partially cut open,

Ed. 2 a section along the line 2-2 according to Pig. 1,

i'ig. 3 shows an individual view of the collector on a larger scale brushes on top,

Fig. 4 is a side view of a brush on a larger scale.

The motor housing Io has a collector 11 surrounding it Section 12, which at the same time carries the bearing for the motor shaft 15. The housing wall of the housing section 12 has a flattened wall section 14-, in which a symmetrical Recess 15 is arranged. Stand through this recess 15 two leaf springs into the interior of the housing section 12, which with their inner leg 16 the collector 11 under spring - voltage are applied and the outer bent leg 17 is fixed on the flat housing section 14 by means of hollow rivets 18 are. The hollow rivets 18 stand through a bore 19 of the spring section 17 (3? Ig. 4) and a corresponding bore of the flat housing wall section 14 by.

The spring leg 16 is via an arch of curvature E 1 and one Curvature R 2 is connected to the spring leg 17. the The arc of curvature H 2 runs through the recess 15 (! "Ig · 2).

In the rest position of the brush spring shown in FIG the brush handle 16 forms an angle <* t with the straight line lying at right angles to the leg 17, which is a dimension represents the preload.

The brush legs 16 have in. The longitudinal direction Hippen 20, conveniently from the. Flat material pronounced can be and are substantially U-shaped in cross-section. (Fig. 5). This creates two defined support points created on the collector, whereby the current transfer is significantly improved with uniform contact pressure.

By using standard hollow rivets for fastening the brushes on the flattened housing part, the attachment of the brushes to the front housing part is easy to accomplish. At the same time, as a result of this training, the engine can be as simple as possible Way to be placed on a printed circuit, which ensures the power supply via connector pins of a known type.

Since the preload or the contact pressure of the brushes is determined by the angle </ ~ (Hg, 4), the contact pressure can be set as desired by changing this angle.

Patent claims:

Claims (8)

-ν- P.A.24U84 * 11.5.S5 claims 1. Brush arrangement for DC miniature motors with two Brushes designed as leaf springs, which are tangentially in contact with the collector, characterized in that, that the collector enclosing, made of insulating Motor housing made of plastic has a recess (15) through which the two brush springs protrude, the outside bent in opposite sightings and in its bent part (17) on the outside of the housing wall are set. 2. A brush assembly according to claim 1, characterized in that the outer "barren leg (17) are fixed to the housing wall by means of GSM _e hollow rivets (18). 3 · brush assembly according to claim 1, characterized GEK e η η ~ * characterized in that the housing wall has adjacent to the recess (15) flat contact surfaces (14) for the outer spring legs (17). 4. Brush arrangement according to claims 1 to 3 »characterized in that the .befestigung serving outer brush handle (17) ^ i ^ is equipped with a mounting hole (19) and via arcs of curvature (B2 and E1) opposite curvature with the brush leg (20) is connected, which includes an adjustable angle oL with respect to the perpendicular to the leg (17). 5. Burst en arrangement according to claims 1 "to 4 ·, thereby g e -j indicates that the one holding the brush springs G-ehäuseab section (12) is designed as a cover and a Bearings for the motor shaft (13). 6. burst arrangement according to claims 1 to 5 »dadureh characterized in that the guarantees over the hollow rivets (18) and pins can be connected to a printed circuit. 7 · Brush arrangement according to claim 1, characterized in that one of the brush legs »the Contact the collector, is extended and protrudes through a housing opening, so that at this section a Can attack brush lifting causing actuator. 8. brush arrangement according to claim 1, dadureh g e k e n η - draws that the with the collector (11) in contact coming legs (16) of the brush springs at least has two ribs (20) running in the longitudinal direction 9 «Brush arrangement according to claim 8, dadureh geke indicates that the ribs (20) are U-shaped in cross-section.