US1369408A - Commutator and commutator-bar - Google Patents

Description

F. DIEHL.

COMMUTATOR AND COMMUTATOR BAR.

APPLICATION FILED APR. so. 1918.

1,369,408. Patezited Feb. 22,1921.

2 sHEE Ts-sHEET 1.

F. DIEHL.

COMMUTATOR AND COMMUTATOR BAR.

APPLICATION FILED APR; 30, 191B.

Patented Feb. 22, 192 1.

2 SHEETS-SHEET 2.

521/67 Li /f jhwywk Ja /J UNITED s'ra'nzs PATENT OFFICE.

FEEDER-ICE DIEKL, OF ELIZABETH, NEW JERSEY, ASSIGNOB 1'0 DIEHL MANUFAC- TUBING 00., OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

To all whom it may concern Be it known that I, FREDERICK DIEHL, a.

citizen of the United States, residin' at Elizabeth, in the county of Union'and tate of New Jersey, have invented new and useful Improvements in Commutators and Commutator-Bars, of which the following is a specification.

This invention relates to commutators and commutator bars for dynamo'electric machines and the like.

It is the present common practice to construct commutators for dynamo electric machines and the like of insulated bars or segments of copper. Copper is soft and ex ensive compared to some other metals. owever, when other metals, ordinarily of greater lasting quality and less expensive composition, such as steel or iron, are substituted for copper difiiculty is encountered with objectionable pitting and wearing of the segments because of the sparking and arcing which occurs between the brushes and the segments. and consequently the pitting and wear, is most noticeable at the rear or trailing edges of the segments.- Difficulty is also encountered in satisfactorily uniting the copper armature conductors with commutator segments of a different metal.

One of the objects of this invention is to provide a commutator bar and a commutator having improved wearing qualities.

Another object is to provide a bar and commutator in which the injurious effects of sparking and arcing are reduced.

Another object is to provide a bar. of this character whereby the armature conductors may be readily and securely attached by the usual processes such as soldering, welding, brazing and the like.

Another object is to provide, in a commntator composed of bars having difierent metals, a' means for effecting an improved connection with a'terminal. 0 Another object is to-provide arr-improved. mechanical and electrical connection between an armature coil and a sheathed commutator bar, so as to effect a common connection with the core and sheath.

Another object is to provide/a means for increasing the capacity of a commutator having bars composed'of diiferent metals.

Another object is to provide-a commuta- The arcing and sparking,-

' provided with composite se OOIIUTATOB AND GOIMUTATOB-BAB.

tor which is comparatively, inexpensive .to manufacture.

Another object is to tor which is simple, reliable and efficient.

Other objects will appear from the followin description and claims.

In t e embodiments of the invention herein illustrated and described the commutator segments or bars are of composite construction, being composed of a core of comparatively inexpensive wear resistant metal, such for example as steel or iron, with a partial envelop or cladding of a higitily conductive spark resistant metal at t eir adjacent edges and to which the armature conductors may be readily united.

v Specification 01' Letters Patent. Patented F b gz, 1921. Application filed April :0, 191a. Seria1Ro.-231, 5 7'9Z I rovide a commutatator bars and commutators of this character may be constructed are shown in the accompanying drawings in which:

Figure 1 is a perspective of a complete commutator ofi the molded type having one form of'composite segments or bars.

Fig. 2 is a side elevation partly in section of a molded commutator like Fig. 1.

Fig. 3 is an end elevation partly in section.

Figs. 4 and 5 are respectively end and side elevations of a form'of core of the improved segment. a

Figs. 6, 7 and 8 are respectively end, side elevations and a plan of an envelop orcladding of high conductivity spark reslstant metal.

Fig. 9 is a side elevation of a type of insula-tor which may be used between the segments.

Fig. 10 is a side elevation partly in sec tion of a modified construction of a molded commutator.

Fig. 11 is an end elevation partly in section of a commutator of the type shown 111,: Fig. 10. igs. l2 and13 are respectivelyend and side elevations of the type of sect on male ing up the cores of the segments shown in Fi .10 and 11. w

f igs. 1e, 15 and 16 are respectively end and side elevations and a plan of the type of envelop or cladding used in the inc ined construction, and

Fig. 1'? ice side elevation. partly in sec tion of a commutator of the non-molded type gments.

Iyefer'ring to. Figs. 1 to 9 inclusive the ice commutator is made up of composite segments or bars held in place by a body of molded insulating material 1 surrounding and carried by a suitable sleeve 2. The molded material may be any one of the many suitable materials known to the art. An example of such a material is bakelite, which alone and in composition with many other substances has been found to give good refects of sparking or arcing between the segments and the brushes and to provide for the ready uniting of the armature conductors and the commutator segments each core or section 3 is embraced along ItS adjacent sides and one end with a partial envelop 4 of a highly conductive spark resistant, easily soldered, welded or fused metal. Copper has been found to give excellent results. These envelops, as clearly shown in Figs. 6 and 7, have two sides 5 and 6 of approximately the same size and shape as that of the core 3, and an end piece 7 covering one end of the core.

The commutator is constructed by placing the required number of complete. composite commutator segments, each made up of a section 8 and a section 4, around the sleeve 2 in a suitable mold. The segments are spaced apart and further insulated by insulating strips 9 of mica or other suitable material. It has been found, however, that, in certain cases, the mica need not-be used but that the molded material may be depended upon [to provide the necessary insulation. Themolded material is then inj ected into the mold and allowed to set. The

, assembled commutator may then be removed and if necessary turned down to remove any inequalities in the segments or. insulating strips.

The copper clad end of each segment is then provided with a notch 10 by millin or other suitable operation. Into these s ots the ends of the armature conductors may be placed and since their edges are of copper a good connection may be easily made by soldering, brazing, welding, etc. By connecting the armature conductors with the segments so as to form a common connection with the core and sheath, the conductivity is increased. Further, such a connection has mechanical and thermal advantages. Th increased area of contact affords a stronger mechanical connection and more readily dissipates heat.

A arallel path is provided for the current from the armature coil, by providing a means for effecting a common connection with the core and sheath which are of diiferent conductivities. A maximum current-can rying capacitiy for a given amount of cop per is then obtained.

Figs. 10 to 16 inclusive show the assembly and details of a modified constructionwhere-' in each commutator segment or bar is composed of two composite sections. Each segment section comprises a'core 12 of iron or steel and a partial envelop 13 of copper covering the adjacent sides of the cores. The cores 12 may be made in the form usually adopted for commutator segments as shown in Figs. 12 and 13.

The envelops 13 of copper have two sides 1a and 15 and a bottom 16 arranged in a somewhat V shaped form, such as most clearly indicated in Fig. 1a, to closely embrace the sides of the cores 12. The sides 14 and 15 of the envelop 13 may also take the form of the usual commutator segment, as most clearly indicated in Figs. 15 and 16, to conform to the shape of the core 12.

The commutator is formed by placing the required number of composite segments, each comprising two of the cores 12 and two of the envelops 13 in proper spaced relation about a sleeve 17 in a. suitable mold. The molded material 18 is then forced into the mold and allowed to set. After the molded material has set the completed commutator may be removed and turned down if necessarv.

In order to provide for ready attachment of the armature conductors to the commutator segments slots 19 may be milled into the ends of the engaging edges of the envelops of each composite bar. This provides for the ready uniting of the copper armature conductors with the copper portions of the composite segments by soldering, welding, brazing, etc.

Fig. 17 shows how composite commutator segments made up in either of the ways hereinbefore described may be utilized in the construction of a commutator of the usual non-molded type. The commutator segments 21 which, for the purpose of illustration, are shown as of the type disclosed in Figs. 10 to 16 inclusive, are securely held in place by two circular wed e shaped retaining members 22 and 23. I ember 22 is threaded at one end for the reception of a suitable threaded collar 24 which when turned into position firmly clamps both members 22 and 23 against the bases of the commutator segments. Members 22 and 23 are insulated from the commutator segments by suitable insulation 25 and other insulat- Instead of making each commutator segment of two or more separable composite sections, as hereinbefore described, the segments may be made by completely copper cladding the iron or steel core in a manner similar to that employed in the production of copper clad steel or iron wire. With such a construction, after the commutator is assembled and the segments are anchored in position by the molded material or the usual metallic and insulated construction, the surface is turned down until the circumferential layer of copper is entirely removed.

The segments then have the same appearmaterial, such as steel or iron, ma be obtained without the usual resultant 0 ectionable itting due to arcing and sparking and the diflicu'lty of uniting the copper armature conductors and the iron or steel segments.

The copper cladding for the iron or steel cores of the segments extending along and in close engagement with the adjacent sides of the segments provides a spark and are resistant material at the points where sparks and arcs most readily occur. The envelops or cladding being practically, in effect, united to the iron or steel cores also provide a ready means for securin the armature conductors to the segments without material,

if any, increase in the resistance.

The sections comprising a complete commutator segment may be readily stamped into the desired sha and size and the copper envelops are easily bent to the necessary form. The production of the commutator then merely necessitates the assembl and collection of the requisite number 0 composite sections which may be made into a complete commutator in any of the ways now well known in the art. The manufacture of commutators of this type is, therefore, simple andinexpensive and in general along the lines usually employed.

What I claim is:

1. A commutator-bar comprising a core of wear resisting material and an outer sheath of copper, said sheath and core having alining slots for the reception of an armature lead, whereby the lead may be brought into contact with both the sheath and core to increase the current carrying capacity and todecrease the resistance.

2. A commutator bar having a core of a wear resisting metal and an enveloping sheath surrounding two sides and an end of the core and terminating at the upper surface of said bar, said bar having a slot in its body in the sheath'and core for the reception of armature leads, whereby the leads may be brought into contact wlth the core and sheath to obtain relatively high conductivity.

A commutator bar comprising a central core of a conducting wear resisting material, an outer relatively thin sheath of copper, said sheath and core terminating in a common plane, and means for effecting a connection with both the core and the sheath to increase the capacity of the commutator for a given amount of copper.

i. A commutator bar comprising a central core of metal having relatively low electrical conductivity, an outer sheath of metal of relatively high electric conductivity, and means for effecting a common connection with the metals of different conductivities, whereby the combined conductivity is increased.

5. A 'commutator bar comprising a central core of material containing iron, a copper sheath for the core, and means effect ng a connection between a copper conductor and the copper sheath and the core.

' 6. A commutator composed of bars having a central core of ferrous material, a sheath of copper, and means for effecting the connection of an armature coil 'with the bars, wherebythe core andsheath are connected in parallel relation. I

7. A commutator comprising a plurality of metals having difi'erent electrical characteristics, and means for connecting an armature coil with said bar so that the metals provide a parallel path for the current from the coil.

- In witness whereof, I have hereunto subscribed my name.

. FREDERICK DIEHL.

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