DE7025828U - BRUSH HOLDERS FOR ELECTRIC MOTORS, IN PARTICULAR Cranking motors for motor vehicles. - Google Patents

Description

R. 9908 Sh / Kf
6.7.1970

Attachment to
Utility model registration

E OBERT BOSCH GMBH, 7 Stuttgart (Germany)

Bürstenha l ter for 3 1 tr ek ise he Maschi ner., I nsbe so ther Andrehmotore n for motor vehicles

The invention relates to a brush holder for electrical machines, in particular starting rotors for motor vehicles a housing guiding the grinding brush and a helical spring attached to the brush and a perpendicular to the brush axis arranged shoulder of the brush shark and the brush presses against the circumferential Gegerikontaktbahn of the machine.

Robert Bosch GmbH R. 9908 Sh / Kf

Stuttgart

In particular in the case of electrical machines with commutators, it is important to keep the machine running over a long period of time To achieve gnite commutation when running the brush holder To strive for a spring characteristic that is as flat as possible, so that the contact pressure of the brush on the commutator also increases strong abrasion of the brush is still about the same as with newly installed brushes.

In a known brush holder, the grinding brush is guided by a coil spring guided in a spring holder, which is attached to the the collector facing away from the face of the grinding brush attacks, pressed onto the collector. To make this as flat as possible To achieve spring characteristics, a spring with a large number of turns, i.e. a large spring length, must be installed. This leads to large dimensions of the spring holder in the radial direction and thus to a considerable amount of space required for cramped Installation space is often not available.

In a likewise known embodiment of a brush holder wildly pressed the carbon brush onto the collector by spiral springs. With this construction, the brush holder can be opened accommodate the smallest space, however, the non-linear (progressive) steep spring characteristic of the spiral springs has a disadvantageous effect the end; because with increasing abrasion of the brush, the contact pressure decreases relatively quickly, which worsens the commutation will. The only remedy is to replace it at an early stage of the carbon brushes.

The invention is based on the object of creating a brush holder which is very small and a contact pressure of the carbon brushes generated, which changes little with increasing abrasion.

The object is achieved according to the invention in that at least two helical springs lying one inside the other are initially pressed against the brush

Robert Bosch GmbH E. 9908

Stuttgart

preferably the opposite direction of winding is provided.

Due to this design and Aixox expansion of the brush compression spring.?! is it is possible to achieve flat spring characteristics with tight tolerances in the smallest of spaces.

A particularly advantageous construction of the brush holder is achieved if you arrange the coil springs in a housing-like retaining member, the bottom of which forms a support shoulder and

. Its side walls .. · "..,, _, ..,,. ,,. . _T ..

Van the housing that guides the brushes against unintentional loosening are secured. The latter can be achieved in a simple manner that the holding member at least two over the housing has gripping legs, each of which has an inwardly pointing projection which is inserted into a corresponding recess of the Housing clicks into place.

In the drawing, an embodiment of the subject matter of the invention is shown. Show it:

1 shows the brush holder according to the invention in side view,

FIG. 2 shows a section through the brush holder along the line H-II in FIG. 1,

Fig. 3 is a perspective view of an individual part of the Brush holder and

FIG. 4 shows a variant of the brush holder according to FIG. 1.

'The brush holder consists of a carbon brush 11 receiving frame-like housing 12, one of which has a frame leg with side flanges I3 for fastening to the machine housing, for example on the bearing plate. The built-in

Hobert Bosch GmbH R. 9908 ShAf

Stuttgart

Housing 12 is arranged to the collector 14 that one end face the brush 11 rests on the collector lamellas. On the opposite end face of the brush 11, two engage coaxially mutually arranged coil springs 15 and 16 with rectangular η Winding cross-section, which are supported on the inner bottom surface of a spring holder 17. The coil springs 15 and 16 are on guided by a pin 18 protruding from the bottom surface of the spring holder 17, onto which the inner screw member 15 is pushed. The two coil springs 15 and 16 have opposite one another Winding sense, i.e. one spring is right-handed and the other is left-handed.

The pen holder made of electrically insulating material 17 has four legs 19, each of which has an inwardly pointing projection 20 at its end. With these advances, it stops the spring holder 17 in corresponding recesses 21 on the housing a. The power supply to the carbon brush 11 takes place via two strands 22.

In Fig. 4 is a variant of the brush holder according to the invention shown. Here are two sets of helical springs with ^ e two nested Screws 15 and 16 or 15 'and 16' next to each other arranged. To guide the coil springs, the inner bottom surface of the spring holder has two pins 18 and 18 '; the power supply to the carbon brush is done for better power distribution over three strands 22.

7825828-3.2.72

Claims (5)

.L · Bosch GmbH R. 9908 Stuttgart 6.7.I97O claims 1. Brush holder for electrical Μεschinen, especially starting motors of motor vehicles, with a housing guiding the grinding brush and a coil spring attached to the brush und.an rests against a shoulder of the brush holder arranged perpendicular to the brush axis and the brush against the circumferential one Mating contact path of the machine presses, characterized that for pressing the brush (11) at least two mutually aligned Coil springs (15-16) preferably with opposite V / ickelsinn are provided. 2. Brush holder according to claim 1, characterized in that the helical springs (15 »16) on one of their support shoulder protruding pin (18) are performed, on which the inner helical spring (15) is pushed. 3. Brush holder according to claim 1 or 2, characterized in that the coil springs in a housing-like holding member (17) are arranged, the bottom of which forms the support shoulder and its side walls on the housing guiding the brush (11) (12) are secured against unintentional loosening. Robert Bosch GmbH R. 9908 Sh / Kf Stuttgart 4. Brush holder according to claim 3, characterized in that the holding member (χ?) has at least two legs (19) which extend over the housing (12) and each have one inward Carry pointing projection (20) which engages in a corresponding recess (21) of the housing (12). 5. Brush holder according to one of claims 1 to 4, characterized in that the holding member (17) is made electrically insulating material made irt ~. £> ^ 7825828-3.2.72