US1631461A - Commutator and method of making same - Google Patents

Description

L. BONSIEUR COMMUTATOR AND METHOD OF MAKING SAME June 7, 1927.

Filed m 1. 1924 VIII/"l/IIA I Q I INVENTOR' B 5;, m 5 ATT'ORNEYS.

' Patented June 7, 1927.

UNITED STATES 1,631,461 PATENT OFFICE.

LE BONSIEUR, OF ELYRIA, OHIO, ASSIGNOR TO THE GENERAL PHONOG-RAIPE MANU- FAG'IURING CO., OF ELYRIA, OHIO, A CORPORATION OF OHIO.-

COm'I'A'IOR AND METHOD OF MAKING- SAME.

Application filed December 1, 1924. I Serial No. 753,411.

My invention relates to commutators and the method of making the same, and relates more particularly to the making of relatively small commutators such as are adapted for use upon small electrical motors which may be employed in electrical signal horns, for driving phonograph mechanisms and for driving toy machinery and the like, although my invention is not limited to such muses, but may be employed in connection with the making of commutators for larger motors for driving fans and for other purposes.

An object of the present invention is to simplify the making of commutators for electric motors and the like so that they can be more inexpensively manufactured in quantities.

Another object of the present invention is to accomplish the making of smallsized commutators without the necessity of utilizing any'considerable amount of hand operations incidental to the manufacture thereof.

Another object of my invention is to accomplish the making of small sized commutator'sof the aforesaid types which will be uniform when produced. in large quantities and which will be rugged when completed and which will retain their ability to perform the commutating function in electric motors even when used for long periods under. severe conditions of use.

Another object of the present invention is to economical y produce in large quantities small-sized commutators in which the insulating medium may be applied as a plastic and which when congealed will efiiciently hold together the commutator segments and resist deforming of the commutator by the single or conjoint efi'ects ofheat and mechanical shocks.

.' Other objects of my'invention and the inventioaitself, will become apparent as the description of certain em iments, thereof herein illustrated and described progresses.

-Refe1ring to the drawings'forming a. part Fig. -1 shows a' side' elevational view of. a

commutator constructed accordingflto the of themethod described herein; 6 4

Fig.2 shows the commutator of "Fig. I

viewed from the rear, the view beings. plan view; i 1

the space between the tube 2 and the segprinciplesof my invention by employment Fig. 3 is a transverse section taken on the line 33 of Fig. 1;

Fig. 4 is a longitudinal medial sectional view taken on the line l 1 of Fig. 2;

Fig. 5 shows a plan view of a sheet metal stamping comprising the commutator segments extending radially from a common center and being joined together adjacent such center;

Fig. 6 shows an end view of the joined commutator segments of Fig. 5 subsequent to a bending operation in which the radially extending segments of Fig. 5 are so bent as to define an approximately cylindrical hollow cup;

Fig. 7 is a side elevation of the formed stamping of Fig. 6:

Fig. 8 is an end plan view of the stamping of Fig. 7 viewing the same from below as shown;

Fig. 9 is an end view of the commutator of Fig. 4 seen from below:

Fig. 10 is a longitudinal media] sectional view of a-tool and die for compressing the congealing plastic insulating material conti' ained within the cup-shaped stamping of In Fi 1 I show a commutator completed and ready to be slipped onto a motor shaft by a tight driving fit thereon preferably, the commutator comprising a centrally disposed tube 2 preferably of soft steel and a lurality of commutator segments 3, 4, 5, 6,

8 and 9 surrounding the said tube 2 and insulated therefrom by insulating material 10 which may be of any of a number of different compositions, but which I will de-' scribe herein as being of that material commonly known as bakelite. This bakelite insulating material extends entirely within ments, and also extends between the seg ments near one end thereof and around the segments as shown at 11. The portion 11 of the insulating material joined to the inner portion 10 thereof forms a band or ring of insulating material outside the com-- mutator segments and adjacent the termi-" nals 12 of the segments, and prevents any ,portion of the solder or sol eri g fluxes employed in soldei'ln electricalconductors to the terminals 12 om flowing out over the content portions 13 of the se ents.

The insulating material also protru es bemechanical blows, shocks and vibrations.

The steel tube 2 is preferably contained within the body of insulating material 10 particularly where the commutator is to be made in the larger sizes-as it may be driven onto a motor shaft very tightly and without the danger of thereby causing the body of the commutator to be expanded unduly and beyond its elastic limit to crack the commutator, The commutator, .however, may be used with or without the tube 2, its use being optional and desirable principally in the larger sizes of commutators. J L

The commutator of Figs. 1 to 4 inclusive is preferably formed from a single sheet metal stamping such as a stamping of brass or copper, ing cut in a form such as that shown in Fig. 5 wherein the commutator segments 3 to 9 inclusive are shown as extending radially from a common center whereat the stamping is referably perforated as shown at 15 and t e segments being joined together b a connecting ring of the stamping material shown at 16. The perforations 17 may be provided, their use being optional, but where provided as-shown the b ank may be more easily bent adjacent such perforations, and the material may be cut away at such perforations somewhat more easily.

The en 3 of the segment portions are referabl formed in the accepted shape or electrical terminals as shownat 12 comprising a,hook portion 18 adapted to receive an electrical. circuit conductin wire which may be soldered to the termmal 12 after the commutator 'has been completed and placed on a motor shaft. The stamping as shown in Fig. 5 is'then placedin a punchpress and in the manner usual for such pressm o rations, the radially extending arms o t stamping comprising the segments 1n the ultimate product are bent into substantially cylindrical form as shown in the figure, and the ring shaped joining porher: 16 forming the bottom wall of the cupshaped article so formed. The resultant integrally formed piece is illustrated inFi 6 to 8 lnclusive which show respectively t e artlcletein (21ndi plan, sideh elpgational dand opposi en an views e 'acent e of the so-cali I ges elusive may be machined at this stage of the operation by running a cutting saw be tween the segment arms. This machining operation, however, may be omitted as the a acent edges generally are suficiently ed segment arms 3 to 9 1nregular and spaced that no machining is necessary. v I I The cup-shaped article is then laced in a die recess and filled with ba elite insulating material in preferably powdered recessed from the surface 23 of t e die and having a stepped portion 24 at the bottom of the cavity, the recess 24 andshelf 22 as well as the interior 25 of the cavity being filled with heated bakelite which While being congealed from plastic condition is subject to the pressure of a pressure tool 19 pressed downwardly over the ends 12 of the commutator segments and into intimate pressure creating contact with the body of lnsulating material congealing within the cavity.

The tool so-called segments in an annular shaped recess on the bottom face of the tool, the depth of the recess being suflicient to clear the ends of the terminals 12.

19 receives the ends 12 of the,

After the commutator is thusformed it ring 16 whereby the segments 3 to 9 inclusive will be separated and electrically insulated one from the other as shown in Figs. 1 and 4. The finished commutator is shown 1n Fi res 1 and 4, and as therein shown comprises a pluralit 3 to 9 inclusive, iaving contact surfaces 52,

of commutator segments' each forming a portion of the complete cylindrical outer surface of the commutator the insulating material 25 connecting all of the segments and holding them against dislodgement, filling the inner se s aces and preventing the spacing t e segments becoming'modified.

The axial bore of t e commutator is made tween of such a size that t 'e commutator will fit tightly on the end of a motor shaft making frictional contact therewith and this frictional contact may be increased by knurling or otherwise roughening the motor shaft at the point where the commutator is forced onto it. I prefer, however, to solder the entab' 120.

I electrical circuit conductors leading the motor armature windings to the terminals 12 of the commutator segments.

Having thus described my invention in different embodiments, I am aware that the same may be practiced according to the principles of my invention, but according to methods departing colorably from the complete method herein described for accomplishing the result of my invention and that the product of the method herein described may be produced by other methods, but such departures will be comprehended in the spirit of my invention and in the accompanying claims.

I claim 1. The method of'making ,a commutator comprising a plurality of segments, consist-, ing of cutting from sheet metal a piece having radially extending arms joined at their inner ends, then bending the arms so as to approximately define a cylindrical cup, then in placing a plastic congealablc insulating compound within the substantially cup-shaped article thereby produced and permitting a portion of the compound to flow between the arms to form a band surrounding the arms but united thereto, and to the rest of the compound Within the arms, permitting the compound to congeal and subsequently removing the portion of .the sheet metal joining the inner ends of the arms.

2. A commutator having a plurality of segments, each of said segments comprising an intermediate portion having an outer contact surface, the contact-surfaces ofthe segments being so formed as to approximately define a cylinder, an end of each segment being turned inwardly, and a body portion of cementitious congealable insulating material uniting and spacing the segments, said body portion having a bore axial to the segment contact surfaces, and an insulating band surrounding the segments at a point adjoining their contact surfaces, said band being united firmly to the said insulating material body portion by connecting insulating material portions extending between the segments.

3. A commutator having a plurality of segments, each of said segments comprising on intermediate portion havin an outer contact surface, the contact surfaces of the segments being so formed as to approximately define a cylinder, an end of each segment being turned inwardly, and a body portion of cementitious congealable insulating material uniting and spacing the segments, said body portion having a bore axial to the segment contact surfaces, and an insulating band surrounding the segments at a point adjoining their contact surfaces.

In testimony whereof I hereunto affix my signature this 25th day of November, 1924.

LE BONSIEUR.

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