DE1538786A1 - Carbon brush structure for electric motors with small and medium power - Google Patents

Description

Portfolio: 6796 Munich, 13. S «pt« Hb «r 1966

to the patent application of

Messrs Edgar P "Eaton, Morristown, K.J., Y.St.A. and David Elow, New Rochelle, A.Y.-, V.St.A.

concerning:

"Carbon brush structure for electric motors: i with small and

medium performance "

Priority: September 13, 1965 »V.St.A.

The invention relates to a carbon brush structure for electric motors with small and medium power · It relates in particular a coupling between a helical spring and a carbon block with low resistance, so that the usual flexible braht bridging is unnecessary.

The use of τοη carbon brushes to form a sliding electrical connection is known «You will be with commutators and slip rings used, which τοη in numerous types Electric motors and converters are attached to the rotor. De the 009813/0484 bad original

Commutator or slip ring is rotating and not completely round can be is the best facility for maintaining one constant electrical contact a spring of some kind. as they are very compact and built into a brush holder can be.

Springs are usually made of steel, but not a good one electrical conductor is. If they are the only means of lei " direction of the current from the brush to the outer circuit are they overheat and lose their hardness. the end Because of this, most brushes are that streams from one or more amps, now run with a shunt composed of flexible copper wire that carries all the electricity.

Recently, new types of pedestrians have been used that meet the requirements Elasticity and also have a low resistance. she consist of alloys of phosphor bronze, beryllium copper and other mixtures, one of which is commercially available under the name "Gortem" is known. Springs made from these materials can be used to make the necessary for Konmiv.tatorbürsten ! to create spring force and allow currents of up to 10 amps. Iioh to lead. It was found that with such Applications encounter other problems, one of which is the need to make good electrical contact between the Bath of the pen and the carbon brush. This pro

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bleiv will continue 'complicated by the fact that when a coil spring is compressed, the turns calibration expand slightly, and if this turns Eind fitted around einon cylindrical Anaatz the brush _T causes a compression of the Peeler a reduction of the contact force and likely arcing.

According to the invention, this problem is solved in that the lower end of the coil spring in a cavity or recess is arranged, which is formed in the upper end of the brush. Then when the spring is compressed, the Maintain electrical contact. The term cylindrical revolving conductor used in the branched description and claims refers to all types of commutators and slip rings used in rotors of motors. It also refers to circumferential «contact segments and Rings that are used to carry the current to the contact pads to direct or interrupt him.

An object of the invention is therefore an improved carbon brush structure, which avoids the disadvantages and limitations of the known gate directions.

Another object of the invention is a low resistance contact between a spring and a commutator brush, for Conducting the current from a commutator to other parts Mötora or an outer circle.

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It is yet another object of the invention to provide the flexible wire base for the smaller motors and 'for other applications -' * possibilities in which the current does not exceed to amperes Eliminate the EU.

Another object of the invention is to reduce the cost of the brush assembly. Another object of the invention is to simplify assembly of engine parts and facilitate repairs.

Another object of the invention is to provide other types of BUr-β parts, the Tiel Plats are booing and they are dangerous can when making contact with a commutator segment or a Sole ring is produced, see below.

Solely it is a goal 4er invention, the or Grinding stable! Did the brush in its holder sweeten and Create additional slide guides by increasing the length of the buret surfaces that are in contact kit of the bracket

The invention includes a carbon brush that is slidably installed in a brush holder. The brush has a cavity or recess at one end for receiving one end of a coil spring. The other end of the helical spring rests against a cap on the holder, whereby the blade is resiliently pressed against a rotating commutator or a slip ring. The recess in the brush can be cylindrical or conical ₉

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or it can be a transverse sole seat or a transverse groove.

In the newspaper there are several examples, for example «formeη of the invention, with like reference areas corresponding Denote parts, and where:

Piss. 1 shows a section approximately the length of a median plane of a known one Brush holder represents, with the wire bridging or ( Wire shunt is shown.

Pig. FIG. 2 shows a relationship with the bristle arrangement according to FIG. 1 along the line 2-2 τρη Pig. 1.

Fig. 3 is a section of a preferred embodiment of the invention and shows a carbon brush old a cylinder smelling recess.

Figure 4 is a cross-sectional view of the Pig bristle assembly. 3 length the line 4-4 of Fig. 3, at Ansioht in the direction of the arrow ·

Jig. Fig. 5 is a section of another form of brush which is a truncated cone-shaped recess for receiving one end of the Spring.

Fig. 6 is a section of another embodiment of a brush also having a truncated cone shaped recess, wherein however the cone is reversed.

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Pig. 7 shows a more complete embodiment of the invention egg the recess is annular.

11g. Fig. 8 shows no embodiment of the invention in use a Solnralbeneohwaiusnut in the upper part of the brush.

I ¹ Ig. 9 shows a section similar to Pig 3 t, the recess having an internal thread to anchor the spring.

Fig. 10 is a section similar to that of Fig. 5, whereof the recess also has an internal thread

FIG. 11 shows a section along the line 11-11 in FIG. 8.

In FIGS. 1 and 2, a known BtirsteiiauTbsu is compared shown. A hollow, usually rectangular "brush holder 10 is old a middle part 11 for the beret mount Mistake. A brush 12A is slidably received in the holder 10 and sits on a commutator 13-, Bas upper end of the Brush 12A has a cylindrical stub or lug 14 which serves to set the lower end of a helical spring 15 or to guide. The upper end of the spring 15 can τοη one Vunterlageoheibe 16 are held, although other elements can be used for this purpose. D) Ie disk 16 becomes held against a cap 17 which is the upper end of the brush holder 10 absohlieest and through a screw thread on this is attached. .

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The electrical connections between the spring ends and the The brush and the cap are not enough to get a good track result in low resistance for the current. Furthermore, if the If the spring is made of steel, currents over 0.25 amperes can no longer be used with appreciable performance or efficiency be durohleited. Therefore, there is a bridge of flexible copper wire with the upper end U of the brush 12A and washer 16 connected to carry all of the electricity This type of construction is expensive but necessary when steel springs are used.

An embodiment of the invention is shown in FIGS. 3 and 4 shown. In this embodiment, the upper part contains the Brush 12B has a recess 21, instead of a bolt or an * set, and the outer flat surfaces of the brush, the one make sliding contact old the inner surfaces 11 of the bracket 10, have a longer run length and therefore tend less Sum pressing as a result of canting, especially when the brush is getting smaller. The lower BnAe of the spring 15 is pressed wrapped in a tight helix that is tight in the recess 21 is seated. The upper end of the spring 15 is at the bottom of the Cap 17A en, whereby the spring is pressed against the brush 12B will. This type of connection at the end of the brush is very useful for a spring under compressive stress, since, as is known, the Coils of a coil spring expand when the spring is compressed will. When the cap 17A is screwed in, the lower end of the spring tries to expand and will

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pressed firmly against the inner surfaces of the recess 21, whereby a good electrical connection is obtained. Is the spring made of beryllium copper or one of the other alloys such as i.B. Gortem, * is the flexible one shown in Figures 1 and 2 Shunt 18 superfluous.

The brush 12D shown in Fig. 6 is another embodiment of the invention 4ar, in which the recess is conical is, but its lower diameter is smaller than the opening. As above, the lower base 2OC is the spring 15 in such a way that it fits tightly into the recess.

Any further embodiment of the invention can include the brush 12B be provided in Fig. 7 with an annular recess 22, to receive the end of the spring 15. The Auseendurohaeseer des The core 23 within the ring should be so large that a firm engagement with the spring 15 and a good electrical transition contact or sliding contact is guaranteed 1st.

In the embodiment inclined in FIG. Θ, the upper part is the Brush 12F provided with a baroque tail groove 24, do that To include spring 15. In this embodiment of the invention the tongue can be pushed into the groove from the side.

In Figures 9 and 10, the recesses 25 and 26 are similar those shown in Figures 3 and 5, except because they have an internal thread, as shown at 27 and 28, .u »to take up the spring 15. The threads have a pitch and

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a deep · that of the helix and the size of the spring are adjusted.

During this build-up mainly for small · engines is used »which use cylinder-high CobBUtators or slip rings * the invented base structure can also be used in any other bureau sub-device with a sliding contact with a moving conductive surface present is.

Patent application

009813/048

Claims (9)

- ίο - claims 1. Carbon brush device for electric motors with a carbon brush with a practically constant cross-section, a brush holder with a hollow central part to allow the brush to slide hold, characterized in that this brush with a recess (21) is provided at one end, defl furthermore a helical spring (15) is provided to hold the brush (12B, C, D, E, P) to hold it resiliently against a cylindrical circumferential conductor, which is connected to a part of the motor, further that the spring at one end with a helical end piece is provided, which is used in this brush hollow brown (21) is to make electrical contact with the sides of this cavity and that a flexible cap (17A) is attached to this bracket (10) for electrical connection with the other end of the spring 2 »Carbon brush device for electric motors, comprising a cylindrical, rotating, axially aligned conductor, with a carbon brush rod, the at least four flat seldom has a brush holder old a hollow part around the The brush can be slidably received, characterized in that the brush has a recess (21, 22, 24, 25, 26) at one end. is provided, further by a screw spring (15) to the other end of the brush resiliently against this circumferential To hold the conductor, these peelers ar 009813/0484 '. BATH one end has a helical end piece, which in this
Brush recess (21, 22, 24, 25, 26) is used to make electrical contact with the rare parts of this recess. put, further by a conductive cap (17A) attached to this Bracket (10) is attached to make an electrical connection to the other end of the spring. 3. Carbon brush device according to claim 2, characterized in that the recess (25, 26) at the end o of the brush with a
Internal thread (27, 28) is provided. 4. Kohlbtirstenvorriehtung according to claim 2, characterized in that the recess (22) at the end of the: r brush is annular
is. 5. carbon brush device according to claim 2, characterized in that that the recess (21) at the end of the brush is cylindrical and accommodates a helical spring with a similar fore. supports. 6. Carbon brush device according to claim 2, characterized in that the recess (21) at the end of the brush is frustoconical and has an undercut side surface, and that one
conical or kegige peder winding similar 3.icher form in this
Recess (21) is used. 009813/0484 BATH 7 · Coal tray assembly according to claim 2, characterized in that it is marked net that the recess (21) in the end of the brush is frustoconical is, where the Btsie of the cone in the small area wit the end face of the brush, and that a conical spring coil (20C) of the same shape is inserted into the recess. 8. Carbon brushes errieMtuxig naoh Anepr-uoh 2, thereby kenneeioh » w nice that the biret at the top BdLt a Bohwalbeneohwansnut provided let a and the © the buIe 'of the spring (15) in Torrn a helix and in the recess (24) is arranged around an electrical contact out @ Hen. F,:; L ^ 9 813/0484 .: ■> / ■■ Lee rs e it θ