CA1046567A - Direct current electric motor - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
In a permanent magnet motor wherein commutator seg-ments have surfaces arranged in a plane perpendicular to the motor shaft for sliding contact with brushes, each brush is made of sheet metal and comprises an inner portion affixed to an end cap of the motor casing, and a substantially annular outer portion united at one of its ends to the inner portion and having an embossed contact on the other end which is resiliently urged into sliding contact with the commutator segment surfaces. The outer brush portion is notched to engage a protuberance on the end cap. A lubricant reservoir is formed either on the commutator or on each brush. The end cap may be locked in position on the motor casing, and the commutator may be mounted on the motor shaft in a predetermined angular position in relation to that of an armature core.

Description

6~67 3 !! Field of the InYention 4 ll This invention relates to electric motors, and in par-¦
~ ticular to direct current motors of the class ~uitable for use in 6 1l to~vs~ portable home appliances and the like. The invention i6 7 j even more particularly directed to improvements in such a direct 8 , current motor of the type wherein each commutator ~egment has a 9 I surface arranged at right angles to the motor shaft for sliding ¦ contact with brushes.

12 Description of the Prior Art 13 In a commutator motor of the above specified type, the14 brushes are usually riveted onto an end cap of a oylindrical motor~
casing or frame, in ~uch a way that the contact portions of the 16 brushes are resiliently urged against the commutator segment sur-17 faces dispo~ed oppo~ite to the end cap. The motor of this type is 18 easier to assemble~ and the brush contact portions can be urged 19 ~ under constant pres~ure against the commutator If, however, each bru~h of such a commutator motor is ¦
21 fastened onto the casing end cap by a ~ingle rivet only, the bru~h 22 is easily loosened by motor vibrations or suffers angular dis-23 placement due to the rotation of the commutator in sliding contact 24 therewith. The loosened or displaced brushes will not make proper Z5 contact with the commutator and will thus ~horten the life of the 26 motor.
27 The fastening of each brush with two or more rivets is' 28 also undesirable because it neces~itates extra time and labor for 29 assembling. Moreover, the bru~h~ which i5 extremely small in Bize will suffer a decrease in strength if two or more rivet holes are .

~04~ 7 1 lf formed therein

2 l It is another problem with the prior art com~utator

3 1I motor of the ~ype under consideration that the contactin~ surfaces

4 ll of the commutator and brushes are often not maintained in a proper l~ state of lubrication. Since the commutator fiurfaces for sliding 6 contact with the brushes are flat and are arranged at right angles 7 to the motor ~haft, the grease or the like applied on these sur-8 ~ Eaces tends to dissipate readily because of the centrifugal force 9 I produced by the rotation of the commutator. When not properly lubricated, the bruQhes made of phosphor bronze, brass or like ma-11 terial are particularly easy to wear out before the expected life-12 time of the motor.
13 A further problem to be considered with the prior art 14 commutator motor of the type in question concerns the installation of the commutator on the motor shaEt in a predetermined angular 16 position relative to the armature. Heretofore~ for this purpose, 17 one of the two diæc-like insulators on oppo~ite ends o~ the arma-18 ture core has been formed to include a positioning boss or like 19 projection which iB to be received in a hole in the commutator or ¦ in some other member arranged intermediate the armature and the 21 1 commutator. Such a positioning bosn, however, is susceptible to 22 ~ breakage during assembling or handling, because the armature in-23 1 sulators are usually made o paperboard or similar material.
24 l SUMMARY OF THE INVENTION

27 It is the primary object of this invention to provide 28 improvements in a commutator motor of the kind specified whereby 29 the above noted and other problems of the prior art are thoroughly overcome.

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,: ' ', ~ ' ' ~ ' ~nother ob;ject of the invention i6 to provide,`in a commutator motor of the kind ~pecified, an improved bru~h const-3 ruction ~uch that each brush can be readily mounted in position 4 1 on the motor and maintained in proper 61iding contact with the S I commutator~ practically without any possibility of displacement.
6 /~ further object of the invention i5 to provide, in a 7 ~ commutator motor of the kind specified, means for ~w~b~ t~e con-8 ¦I tacting surface~ of commutator and bru~hes properly lubricated 9 I over an extended length of time.
A further object of the invention i~ to provide an 11 electric motor having a ca~ing or frame with a cap on one of its 1 end6~ which are 5~ constructed in relation to each other that the !
13 end cap can be positively locked in po3ition on the casing againEt 14 detachment therefrom. 0 A further object of the invention is to provide, in a 16 commutator motor o~ the kind specifled~ improved mean~ for mount-17 ing the commutator on the motor shaft in a predetermined angular 18 pogition in relation to that of the armature.
19 It 1B al~o an object of this invention to provide a commutator motor of the kind specified which can be assembled 22 through a mat0rially ~implified procedure.
In accordance with this invention, summarired in its 23 ~imp~e~t orm, there i~ provided that improvement in a commutator 24 motor of the kind defined which ~omprises a plurality of brugheg mounted on an end cap of a motor ca~ing so as to ride on commuta-26- tor segment ~urfaces arranged in a plane normal to a motor shaft.
Integrally made of sheet metal, each bru6h comprises a first por-28 tion affixed at one point thereon to the end cap, a second portion 29 connected at one end to the first portion and ~enerally extending radlally of the end cap, and a contact formad on another end of :

' ., : ' ~ , i5t~7 1 the saco~cl portion. The ~econd portion i8 SO angled with rcspect 2 to the Pirst portion that the contact is resiliently urged into 3 , sliding contact with the commuta~or segment surfaces. The improve-4 1l ment further comprises means on the end cap for engaging each I brush ~o as to lock same against angular di3placement.
6 ¦ In a preferr~d embodiment of the invention the f$rst 7 I portion of each brush is a~fixed to the end cap by means of a 8 ~ cylindrical connector Pormed integral with a supply terminal. The 9 connector i~ passed through aligned holes in the fir6t brush por-I tion and in the end cap and is clinched, thereby mechanically se-11 I curing the former to the latter and also electrically connecting 12 ~ the brush to the supply terminal.
13 I According to another feature of the invention, the 14 ~ contact on each brush is formed by embossing the sheet metal of which the bru3h is made. A cavlty thu6 formed on the back of the 16 brush contact is adapted to serve as a lubricant reservoir which 17 i8 intended to be filled with a suppl~ of grease or the like for 18 lubricating the contacting surface~ of the brush and the commuta-19 ~ tor. Alternatively~ such a lubricant reservoir can be formed on parts of the aforesaid commutator segment ~urfaces.
21 As an additional feature of the invention, for mount-22 ing the commutator on the motor ~haft in a predetermined angular 23 position relati~e to the armature, one of a pair of armature in-24 sulators is provided with a poæitioning tongue which has been formèd by cutting therein a pair of parallel ~pacad ~lits extend- , 26 ing radially outwardly from its center 3haft hole. The position-27 ing tongue iB adapted to be at least partly raised or turned out 28 of the plane of the armature lnsulator as the motor shaft is in-a,sse,~nb J~'r. 9 29 A serted into and through it~ shaft hole during ~e~ ~ of the~
motor, The tongue o~ this construction is significantly stronger

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~0~ 67 1 th~n the convontiona1 po~itioning boss on the armature insulator 2 : mention~fd previously.
3 I The above and other objects, features, and advantages 4 ll of this invention will become more cloarly apparent as the des-5 1I cription proceeds, with reference had to the accompanying drawings

6 showing preferred ernbodiments of the invention.

7 ,

8 ! BRIEF DESCRIPTION OF THE DRAWINGS
~ ' .
10 I FI.G. 1 is an axial sectional view of the commutator 11 motor incorporating the novel ConGepts of this invention;
12 FIG. 2 is a front elevational view of a commutator 13 used in the motor of FIG. 1, as seen from the right hand side in 14 ¦ FIG. 1;
15 I FIG. 3 is a front elevational view of one of brushes 16 in the motor of FIG. 1;
17 FIG. 4 is a sectional view taken along the line 4 - 4 1 18 of FIG. 3; ~h~ 1, 19 ~ FIG. 5 is a front elevational view of one o~tarminal members in the motor of FIG. 1;
21 FIG. 6 is a ~ectional view taken along the line 6 - 6 22 ~of FIG. 5;

24 ¦ FIG. 7 is an elevational view of an end cap in the Imotor of FIG. 1~ aff3f seen from within its casing 3 together with the 1 pair of bru~hes mounted in position thereon;
26 FIG. 8 i~ an enlarged sectional detail view taken 27 along the line 8 - 8 of FIG. 7;
28 FIG. 9 is an enlarged detail view of part of FIG. 7 as seen in the direction of the arrow 9 of FIG. 8;
FIG. 10 i~ a per~pe~tive view of one of the Begments ''~ . . ' ' ' , ' 'lOL~
1 of a commutator havln~r ~ lubricant reservoir in accordance with 2 thi~ invention;
3 1,; FIG. 11 is a ~ront elevational view of the commutator .
4 llcomprising the sogments of FIG. 10, the commutator being shown a6 1 lncorporated in the motor of FIG. 1;
6 FIG. 12 iB a sectional view taken along the line 12 -7 11 12 o~ FIG. 11~ the view showing the commutator of FIG. 11 together 8 with some assoclated parts of the motor of FIG. 1;

9 ~j FIG. 13 is a sectional view of a brush for use in the 1 motor of FIG. l;
11 FIG. 14 i~ a front elevational view of a pair of 12 brushes each havin~ a lubricant reservoir in accordance with the 13 inventlon, the brushes being shown as mounted on the end cap for 1~ use in the motor of FIG. 1;
FIG. 15 is a view similar to FIG. 14 but showing a I ;
16 modified form of the brushes;
17 FIG. 16 is an axlal ~ectional view showing a motor ~
18 casing or frame and its end ~ap to illustrate mean~ employed by I :
19 this invention for securing the latter to the former;
FIG. 17 is an enlarged~ fragmentary perspective view 21 showing the motor casing and end cap of FIG. 16 bePore the latter I ~
22 i8 mounted on the former; ~ :
-23 ;. FIG. 18 is a view similar to FIG. 17 but showing the 24 end cap mounted in position on the motor caslng and locked against 25 detachment therefrom;
26 FIG. 19 is an exploded perspective view of an armature 27 core and a ~langed sleeve mo~nted on the shaft of the motor of 28 FIG. 1, the view being 0xplanatory of mean~ employed by this in-29 vention for mounting the commutator on the motor shaft in a pre-determined angular position relatiYe to the armature core;
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;56>7 1 FIG. 20 is ar1 onlarged fron~, elevational view of one 2 of a pair of armature in~ulators of FIG. 19 which ha~ a position-3 ing tongue;
4 FIG. 21 i~ an enlar~ed perspective ~iew of the flan~-1 ed ~leeve of FIG. 19;
6 FIG. 22 is an enlarged, fragmentary vertical axial 7 ¦ sectional view of the armature insulator of FIG. 20 as shown in a , 8 ~I condition before insertion of the motor Rhaft into it6 hole;
9 FIG. 23 is a view similar to FIG. 2~ but showing the motor shaft inserted into and through the hole in the armature in-11 ~ulator to raise the po~itioning tongue to its working position, 12 the view also showing the flanged ~leeve of FIG. 21 mounted sub-13 sequently on the motor shaft; O
14 FIG. 24 is an exploded perspectiYe view explanatory of the way the ar~ature core and the commutator are assembled and 16 1 mounted on the motor shaft in their predetermined relative angular 17 positions; and 18 FIG. 25 i8 a perspective view explanatory o~ a method , as~rnblihq 1 1 1~ A of ~lyingUcommutator segments with a commutator insulator.

23 - With reference to FIG. 1 the commutator motor incor-24 porating the principles of thi~ invention broadly compri~e~ a cylindrical ca~ing or frame 30 having a rotatable ~haft 34 extend-26 ing axially therethrough, a permanent magnet 37 fastened to the 27 inside of the motor ca~in~ to create a congtant magnetic field~ anl 28 armature 41 ~ixedly mounted on the shaft and disposed in the field 29 of the permanent magnet, a commutator 50 al~o fixedly mounted on -:
3D the shaft and electrically connected to armature coil~, not shown, ~;~
.. .

~ ' " ' . , ' ' 5t~
1 ~ and a pair of brusho~ 60 r~.ding on the commutator for electr.lcally 2 connecting the armature colls to a power supply 80 as to permit 3 1l reYersal of the current in the armature coils.
4 ~ Thc motor ca6ing 30 i~ open at its right-hand end 32, 1 ~ I which is closed by a cap 33 of electrically lnsulating material 6 1l such as rigid pla~tics. The closed left-hand end of the casing 7 ~l 30 has a hole 31 formed contrally therein to accommodate an oil-8 I less metal bearing 35. The end cap 33 is Eormed to include a 9 I bearing 36 located centrally therein, and the shaft 34 is rotat-ably slapported by these bearings 35 and 36. The left hand end o~
11the 6haft 34, projecting out of the bearing 35, i8 intended to ¦
12 provide means for imparting motor rotation to a desired external 13 mechanism to be driven by the motor.
14The armature 41 comprises a core 38 of thin sheet-- steel members stacked together in the axial direction of the ~haftl 16 34, a pair of insulator~ 39 and 40 between which the armature core¦ :
17 iB sandwiched, and the unshown coils, a~ will be later described 18 in more detail in connection with FIG. 19. A spacer 42 is mounted 19 on the shaft 34 between the armature 41 and the bearing 35.
As will be seen also from FIG~ 2~ the commutator 50 21 ¦ arranged between the armature 41 and the casing end cap 33 com-22 prise6 a plurality of 7 three in the illu6tra-ted e~bodiment, seg-23 ments 51 of copper or like electrically conducting material elec-24 trically in~ulated from each other and from the shaft 34. Arrang- .
ed radially about the shaft 34, these commutator segment6 have 26 6ubs*antially sectorial surface6 51a which are arranged in a plane 27 normal to the axis of the ~haft 34 and opposite to the casing end 28 cap 33 for sliding contact with the pair of brushes 60. Radial - .
29 gaps S e~i~t between the commutator segments. Tongues 52 project :~;
radially from the ro~pective commutator ~egmant~ 51 for electrical ,' . -g_ , '' i . .
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;7 1 connection to the un6hown armature coils. The commutator se~ment 2 ; arrangcmcnt a~ shown in FIG. 2 has been known and does not, by it-, 3 sclf, con~titute a feature of this invontion.
,~ 1 The commutator segments 51 have their in~ide ends benk !I d~sc IIke 5 ~1! right angularly at 53 to engage a ~ e commutator insulator 58 6 11 of paperboard or plastics. Th0 commutator segment~ with their in-7 ~Isulator 58 are mounted on a flanged commutator core 57 of elec-8 I trically insulating material such as plastics fixedly mounted on 9 the shaft 34. Arranged between the armature 41 and the commutatorl ~50 is a flanged slee~e 54, also of electrically insulating materia 11 Isuch as plastic~ having a small diamèter hole 55 and a large dia-12 meter hole 56 formed therethrough in axial alignment. The small 13 diameter hole 55 recel~es the shaft 34 as with a press fit, where-14 as the large diameter hole 56 receives the commutator core 57, also as with a press fit. The commutator segments 51 with the in-16 sulator 58 are caught between the flanges of the sleeve 54 and the~
17 commutator core 57.
~ss~b/l' 18 The manner of ~u=~ ~ of the armature 41 and the 19 commutator 50 with the shaft 34 is later de~cribed in greater de-tail with reference to FIG. 24 -21 The pair of brushe~ 60 are mounted on the casing end 22 cap 33 in diametrically opposed po~itions. Ea~h brush 60 has an 23 embossed contact 62 adapted to ride on the surfaces 51a o~ the 24 commutator segments 51. 1~
25 1 As shown in greater detail in FIGS. 3 and 4, each , - ~~;
26 brush 60 is formed by punching a sheet of phosphor bronze or like 27 electrically conducting material into the illustrated shape. More 28 specifically, each brush 60 compriges a substantially annular or 29 heart-shaped outer portion 61 generally extending radially of the casing end cap 33 and carrying the embossed contact ~ on one o~

_ 10 -- . -.:

ki7 1 i-ts en~s, and a circular inner portlon 64 having a mounting hole 2 65 therethrough and uni.ted at 63 to the other end of the outer 3 ,portion. The outer portion 61 complotely surround6 the inner 4 ~ Iportion 64 and is sl~aced therefrom except the e~e~ portion 63.
~ The outer portion 61 of each brush 60 has a notch 66 6 1 at its end remote from the contact 62. The apex or pointed end of 7 ~Ithis notch 66 and the centers of the mounting hole 65 and the con-~ l,tact 62 are aligned in the radial direction of the caslng end cap ~
9 33. It will be observed from FIG. 4 that the outer portion 61 is ¦
¦di6posed at an.angle to the inner portion 64 ~o that the contact`i ¦
11 62 on the outer portion may be resiliently urged against the sur-12 faces 51a of the commutator segments 51. ¦
13 FIGS. 5 and 6 illustrate the detailed configuration of 14 a terminal member 70 mounted on the ca~ing end cap 33 and connect-ed to each brush 60. Integrally molded of electrically conductlng 16 material~ the terminal member 70 includes an up~tanding connector 17 71 in the shape of a hollow cylinder located adjacent one of it~ I
18 ends and adapted to be relatively neatly inserted into and throughl 19 a hole in the casing end cap 33. The other end of the terminal member 70 is slotted at 72 to provide a supply terminal 73.
As will be seen from FIGS. 7 through 9, the casing end 22 cap 33 i~ integrally provided with an annular rim 43 which fits in . .
23 the open end 32 of the casing 30. The rim 43 has a pair of V- ~ ;
shaped protuberances 44 formed in diameterically opposed position~ ~ .
theréon with their pointed ends directed toward the center of the 2fi cap. The casing end cap 33 has formed therein a pair of holes 46 which are located radially inwardly of the respective protuberance~
28 44 on the rim 43 for receiving the connectors 71 of the terminal 29 members 70. A pair of radial grooves ~5 are formed in the outAide ~urface of the casing end cap 33 ~or receiving all but the con- ::~
:,' : - .~ . , - .
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6~;7 1 nectorfi 71 of the terminal membor~ 70.
2 Thus, for mounting the pair of brushes 60 together with 3 the pair of terminal member~ 70 in po~ition on the casing end cap 4 ~ 33, the cyllndrical connectors 71 of the terminal members are in-5 ¦1 ~erted into and through the respective holes 46 from without the 6 ~cap, and the flat portions of these terminal member~ are fitted in 7 ~ the groove~ 45. The connectors 71 pro~ect inwardly of the casing 8 ~~end cap 33, and the bru~hes 60 are mounted on the projecting end~
9 of the connectors by receiving them in the mounting hole6 65 in their inner portions 64. In thus mounting the brushe~ 60, the 11 notches 66 in their outer portions 61 are fitted over the protu-12 berance~ 44 on the rim 43 of the casing end cap 33 so that the 13 brushe~ may be locked against any possibility of angular displace-14 ment about the connectors 71 in spite of the rotation of the com- , 16 mutator 50 in,~liding contact therewith.
16 With the contacts 62 of the brushes 60 thus disposed 17 in exactly diametrically opposite positions on the ca~ing end cap 18 33, a compr0ssive force may be exerted axially on the connector 19 71 of each terminal member 70 by means of a suitable tool so as to' clinch its projecting end a~ best shown in FIG. 8. The brushes 60l ~- ;
21 are now mounted in position on the casing end cap 33 and are also 22 electrically connected to the respective supply terminals 73.
23 ` AB mentioned previously~ the outer portion 61 of each 24 brush 60 is angled away from the inner portion 64, so that with ;:
the brushe~ mounted on the casing end cap 33 in the above de6crib-226 ed manner, the embos6ed contact~ 62 on the outer brush portions 28 can be resiliently urged against the surfaces 51a of the commuta-tor segments 51. Thus, as the pair of supply terminals 73 are 29 connected to, for example, a dry cell or cell6 via leads, not ~ :
shown~ an electrical connection can be e6tablighed between the un-, - 12 -:- - , , , ~ . : .'.

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1~ 1139LtiS67 1 Ij shown armature coils and the direct current power supply via the 2 ¦ commutator 50 and the brushes 60.
3 ¦ The operating principles of the direct current commu- ¦
4 I tator motor of FIG. 1 are believed to be well known, so that the 6 description of such operating principles will be omitted.
7 ¦¦ The brushes 60 according to this inYention being con-8 ¦I structed and mounted in position as hereinbefore described, the ~ I~effective length~ of each brush (by which is meant the brush length contributing to resiliently supporting the contact 62) is 11 maximized with respect to the physical length of the brush in the 12 radial direction of the casing end cap 33. The contacts 62 of 13 these brushes will there~ore remain positively urged against the I ~
~ commutator segment surfaces 51a throughout the lifetime of the I ;
motor.
16 Although each brush 60 according to the in~ention is 17 affixed to the casing end cap 33 only at its inner portion 64 by 18 the connector 71, the brush can be positively restrained from an- I
19 gular displacement by the V-shaped protuberance 44 fitting in the j notch 66 in its outer portion 61 in spite of the ro*ation of the 21 commutator 50 in ~liding contact therewith. Furthermore, with the 23 brushes 60 thus mounted in position by the connectors 71 formed integral with the supply terminals 73, no additional means are 24 nece6sary for the desired electrical connection therebetween.
It should also be noted that each brush 60 is not se-26 cured to the casing end cap 33 at its inserting portion 63 bridg-~

28 ing the outer and inner portions 61 and 64. This helps to hold 29 the contact 62 resiliently supported ln spite of the possible axial displacement of the commutator toward the brushes.
Whlle in the illustrated embodiment the notch 66 is ~)4~7 1 : formed at the end of the outcr portion 61 of each brusl1 away from .
2 ~ the contact 62, it i8 possible to form such a notch in the inner 3 ~I portion 64. For ~xample~ as indicated by the dot-and-dash lines 4 ! in FIG. 3, the inner portion 64 oE each brush may be slightly ex-~I,tended toward the con~act 62 and may be notched at 66a. In this 6 1I ca~ the protuberances 44 on the rim ~3 of the casing ~nd cap are 7 of course unnecessary, and instead a similar pair of protuber~nces 8 are formed on the insido surfaces of the cap so as to fit in the 9 Irespective notches 66a when the brushes are mounted in position thereon.
11 FIGS. 10 through 12 illustrate a commutator 50' in ac-~
12 cordance with this invention, *or use in *he motor of FIG. 1, that 13 has formad thereon a lubricant reservoir whereby the commutator is 14 rendered self-lubricating~ Like the commutator 50 of FIG. 2, the commutator 50' comprises three segments 51~, and each commutator 16 segment has an arcuate ridge 80 formed on its surPace opposite to ~ ;
17 the brushes 60. The arcuate ridges 80 on the three commutator 18 segm0nts extend along the perimeter of the commutator so as to re-l9 present in combination a discontinuous ring bounding surface por-20 ~ ~YM~ 81 of the commutator segments to provide the lubricant re-servoir 84. :
22 Each arcuate ridge 80 has a flat top 83 of sufficiont 23 width to remain in sliding contact wlth the contacts 62 of the 24 brushes 60 during rotation of the commutator. In this particular embodiment each commutator segment 51' is shown to have a surface 26 portion 82~ on the outside of the arcuate ridge 80, that is flush 27 with the surface portion 81. If desired~ however, this surface 28 portion 82 may also be raised and disposed flush with the top 83 29 of the ridge 80. j In the use of the commutator 50~ in the motor of FIG.1 , - 14 -.. ~ . ' . ...

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65~7 1 a ~uitably thick l~lbricant such as the usual grease may be eilled 2 in its lubricant reservoir 84. Thc arcuate ridges 80 bounding the 3 11l lubricant reservoir prevent the lubricant from ready dissipation due to the centri.fugal Porce exerted thereon during commutator ro-¦
Itation. The lubricant will neverthelQss gradually flow out onto 6 tho tops 83 of the arcuate ridges 80 to minimize the wear of the 7 commutator segmen-ts 51' and of the brush contacts 62, thereby 8 helping to extend the service life of the motor.
9 FIG. 14 illustrates another embodiment wher0in the lu-bricant reseruoir iB formed on each brush, instead of being formed 11 on the commutator as in the preceding embodiment. Each of the 12 pair of brushes 60' shown in FIG. 14 has a relatively large con- j 13 tact 62~ formed thereon by embossing, in such a manner that each 14 brush contact has a relatively large and deep cavity 91 on its back which is to serve as the desired lubricant reservoir 92.
16 The pair of brushas 60~ having the lubricant reservoirs 92 are mounted on the casing end cap 33, in the manner previou61y 18 described in connection with FIGS. 7 through 9~ so as to extend horizontally when the motor i~ installed in a prescribed upright i ~ ~ :

21 disposition. The lubricant reservoirfi 92 have open or recessed 22 ends 93 arranged opposite to each other.
In the use oP these brushes 60~, grease or the like is 23 fillëd in their lubricant raservoirs 92. As heat i6 created fric-24 tlonally in the brushes 60~ by the commutator 50 rotating in slid-ing contact therewit}l, the grease in the reser~oirs 92 will dec-2C rease in vi~c08ity and flow out of the open or recessed ends 93 -28 onto the surfaces of the contacts 62~ to lubricate same. The pro-29 ~ision of the lubricant, re~ervoir6 92 to the brushes is advantag eous in that the lubricant illed therein ig not subject to any centrifugal force tending to dissipate same, 80 that the contact-. ,, . . ........................... .. :

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n, q, I n~~ Q, ~ r~ ~ <
1 ing sur~aces of the commutator and ~rushes will be h~ luhricated 2 ~' for an e~tended len6th of time.
FIG. 15 i.~ intended to manifest the fact that the principle~ of the FIG. 14 embodiment are applicable to other types!
of brushes as well. .~ pair of brushes 60" shown in FIG. 15, af-fi 1 flxed to the casing end cap 33 in vertically spaced positions ~ r 3 ~ d 7 thereon, have olong~to arms 95 extending toward each other and ly-8 ing on oppo~ite sides of the motor shaft 34. Each brush arm 95 9 is embossed at 96 to provide a contact facing the commutator 50 and a lubricant reservoir 97 on the back of the contact. ~s in 11 the FIG. 14 embodiment each lubricant reservoir 97 has an open or 12 recessed end disposed opposite to the motor shaft 34. As grease 13 or the like is filled in the reservoirs 97, therefore, the con-14 tacting surfaces of commutator and brushes can be lubricated as set forth above in connection with FIG. 14. 1 16 FIGS. 16 through 18 illustrate the way the end cap 33 17 i9 installed on the open end 32 of the motor casing 30 and pre- ~

18 vented from detachment therefrom in accordance with this invention~. -. The caslng 30 has a pair of diametrically opposed slots 100 formed 21 in its open end 32, each slot extending from the open end of the casing in its axial direction to a relatively short extent.
22 As best shown in FIGS. 17 and 18, the end cap 33 is 23 1 rimmed at 43, a~ mentioned previously with re-erence to FIGS. 7 ~

24 through 9~ and is further flanged at 101~ with the flange project-ing outwardly beyond the rim. The rim 43 has a pair of tongues 26 102 formed in diametrically opposed positions thereon so as to 27 project in the direction away from the flange 101. The rim 43 and 28 flange 101 are further formed with a pair of V-shap0d notches 103 29 in register with the respective tongues 102. These notches have their pointed ends 104 dlrected toward the respective tongues 102.

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''~ . :~ ' ' . ' , '' , 1 ` For ins-~allation of the cap 33 on the open end 32 o~
2 the motor ca~ing 30~ the rim 43 of the end cap i8 inAerted into 3 ~I the casin~ until it~ end 32 abuts against the flange 101 of the 4 ¦I cap. The cap may then be manually turned relati~e to the casing ¦
5 ~ 60 that the notches 103 in the former may be brought into registe~
6 ~ with the re~pectiv0 slots 100 in the latter. A pair of corners 7 ~ 105 and 106 on opposite side6 of each ~lot 100 are then folded or 8 I bent down into the corre~ponding notch 103 so as to engage the D respective divergent surfaces 107 and 108 defining the notch. The

10 ~ cap 33 i~ now locked in the open end o~ the motor casing against `

11 I any po~sibility of accidental detachment. ;~

12 In a motor of this clasa it has been customary to lock

13 the end cap against detachment from the motor ca~ing by mean~ of a

14 pair of relatively narrow tongues on the casing which are clinched~
~o a~ to engage in re~pective recesses of the cap. The pair~ of 16 ~olded corners 105 and 106 in accordance with thi~ invention are ~-17 capable of locking the end cap far more positively than such prior 18 art means, with each pair of folded corner6 functioning ~ubstan-19 tially as a wedge for tightening the cap. 0~ course~ the folded corners themselves are signi~icantly greater in strength than 21 ~ their conventional 44upter part~7 namely, the narrow tongue~. It 22 should al~o be appreciated that these improved results are reallz-ed merely by ~orming the slots 100 in the motor ca~lng 30 and the 24 notches 103 in the end cap 33, and that the end cap can be locked 26 in position slmply by bending down the corner3 105 and 106 o~ the 26 casing into the notches.
27 FIGS. 19 through 23 are directed to mean~ employed by this invention for mounting the co~mutator 50 on the motor shaft 29 34 in a predetermined angular position with respect to that of the armature core 38. A~ seen in FIG. 19 J the armature core 38 is a . ~ ' ' : ' ' ' S~7 1 lamination of ~hin ~he~t ~eel memberg 110 which have been punched 2 in*o the illustrated shape, each having a plurality of, three in the illu~trated ~mbodiment, radial arm~ 111 with constant angular spa¢ings therebetween and a shaft hole 112 located centrally 1 therein. The motor shaft 34 is snugly fitted in the shaft holes 6 112 of the armaturc core members 110, which are all in angular 7 alignment on the shaft. The armature core 38 of cour~e carries 8 the unshown coils electrically connected to the commutator segment s.
l Also mounted on the motor 6haft 34 are the pair of ar-mature insulators 39 and 40 of paperboard or the like which are 11 located on opposlte ends of the armature core 38 and which are 12 identical in shape with each of the core member6 110. The arma~re 13 insulator 40, however~ which i8 located opposite to the ~leeve 54 14 is made slightly different in construction from the other armature insulator 39.
16 AB shown in greater detail in FIG. 20, the armature 17 insulator 40 has a pair of parallel spaced slit~ or cut~ 120 and 18 121 of relatively short extent extending radially outwardly ~rom a 19 centrally located ~haft hole 40a of the armature in6ulator to pro- ~1 vide a tongue 121. This tongue ha~ a free or inside end 122 which 21 may be straight edged or, alternatively, may 61ightly project into 23 the shaft hole 40a. Preferably, the tongue 121 should be radially 24 aligned with one (123a) of the three arms 123 of the armature in-sulator ~o that ~ame may not su~fer a decrea6e in ~trength by the slitting. If desired, the tongue 121 may be crea6ed, prior to as-26~ s~ b l i~
27 oom~l~g~, at its end opposite to the said end 122 80 that the 8 tongue may be readily raised or bent along the crease during a~-24 ~emblage, a~ will be more full~ de~cribed later in connection with FIGS. 22 and 23.
With reference to FIG. 21 the slce~e 54 mounted on the ' ,., : ' `

' ' , ' ~ ' :
' ' 5~7 1 motor shaft 34 b~tween the armature 41 and the commutator 50 com- I
.
2 pris~6 a cylindrical portion 54a and a flange 54b on one end of 3 I the cylindrical portlon. The sleevo 54 has a positioning rece 124 formed in th~ other end o~ it6 cylindrical portion 54a and a , positioning bos6 126, FIG. 19, projecting from it~ ~lange 54b.
6 ~ In ~6~e~b~ the motor 6ha~t 34 may be inserted into 7 1 and through the hole 40a in the armature in6ulator~ as indlcatedj 8 ¦ by the arrow X in FIG. 22. Since the armature in6ulator tongue 9 121 more or les6 projects into the 6haft hole 40a a6 aforesaid, this tongue will then be at lea6t partly raised by the motor sha~tl 11 out of the plane of the armature insulator 40, as indicated by the¦ ~;
12 numeral 125 in FIG. 23. It will be ob6erved from FIG. 23 that the 13 tongue 121 is curved, rather than being sharply bent, 80 as not to 14 cau6e any crack6 or fissure6 in the fibrou~ structure of which the~
armature insulator i6 made. The projecting tongue 121 i8 directed~ ~
16 toward the 61eeve 54 which i6 to be mounted subsequently on the I ~;
17 motor Ahaft 34.
18 As shown in FIG. 23, the ~leeve 54 i~ then mounted on 19 the motor ~haft 34~ and the projecting tongue 121 of the armature in6ulator 40 i6 engaged in the rece6s 124 of the sleeve. Thi~
21 61eeve i6 now dispo6ed in a predetermined angular po~ition on the 22 motor ~haft in relation to that o~ the armature in~ulator 40 and 23 therëfore of the armature core 38. The po6itioning bo~æ 126 pro-24 jécting from the flange 54b on the 61ee~e 54 may be ln~erted into a positioning hole 58b, FIGS. 1 and 25, formed eccentricallr in 26 the in6ulator 58 of the commutator 50 mounted ~ub6equently on the ¦
27 motor shaft 34, khereby retaining the commutator ln a predetermined 28 angular position with re~pect to that of the armature core 38, a6 will be more fully under6tood from the following description o~
FIG. 24.

.,., .
:''.......... ' : :~ . .: ':
: : .
:. . , : , ., : .
- . ~ ' ', ~: ' " ' . . . :' . .

4;56~

1 ! FIG. 24 ls ~xplanatory oP the way the armature 41 and , ~.
2 the commutator 50 are a~sembled with thc shaft 34 in thair prede-3 Itermined relatlvc angular po~ltions thereon in the motor of FIG.l.
4 ~l Upon installation of the armature core 38 with it8 insulator~ 39 and 40 on the motor shaft ~4, the sleeve 54 i8 mounted on the 6 shaft next to the armature insulator 40 J with it~ flange 54b di-7 ¦rected away therefrom, and the projecting tongue 121 of that in- .
8 Isulator is engaged in the recess 124 of the sleeve.
9 Prior to installation on the motor shaft 34, the com-10 mutator 50 may be assembled as follows. The three commutator seg- ..
d,sc-l/k~
11 ~ ~ ments 51 are carried by the ~e~}M~ commutator insulator 58 hav-12 ing formed therein a center hole 58a which is significantly 13 greater in diameter than the motor shaft 34, in addition to the 14 eccentric positioning hole 58b. For affixation of the commutator 1~ segments 51 to.. the insulator 58~ the inside ends 53 of the former I ~
16 are bent right angularly and inserted into the insulator center I ~:
17 hole 58a, as mentionsd previously in connectlon with FIG. 1~ ~ugsl 18 51c projecting outwardly ~rom the commutator segments 51 are like-lg wise bent to engage or embrace the periphery of the insulator 58.
The commutator segment-insulator a~sembly thu6 pre-21 pared iB held against the flange 54b of the sleeve 54 which ha~
22 been mounted on the motor shaft 34, and the positioning bo~s 126 23 projéctlng from the sleeve flange 54b is fitted in the eccentric~
24 posltioning hole 58b in the commutator insulator 58. With the commutator segment-insulator as~embly manually held in position 26 against the ~leeve flange 54b, the commutator core 57 i~ then ~n- , 28 stalled by tightly fitting the motor shaft 34 in its axial bore 57c. The cylindrical portion 57a of this commutator core is 29 driven through the center hole 58a of the commutator segment-insulator assembly into the large diameter hole 56 of the sleeve . ' ~ ':

I
! .

.. . . .

. ' .
';' . . . ', 5~7 1 54, with the result that the assembly i~ caught between the 2 ; flanges 54b and 57b of the sleeve 54 and the commutator core 57.
3 'll The commutator 50 is now securely installed on the motor in the 4 ` predetermined angular po~ition in relation to that of the armature I core 38.
6 1 It will have been noted that the commutator i8 as-7 1 sembled and in.stalled in position on the motor shaft merely by the 8 interfitting engagement of its various parts, without re~ort to 9 brazing, ~oldering or other fastening means. Attention should also be directed to the po~itioning tongue 121 of the armature in-11 sulator 40 employed for determination of the angular position of 12 the commutator relative to the armature core. This positioning 13 tongue can be formed merely by cutting a pair of slits in the 14 armature insulator, being urged to its working position of FIG.23 '~
as the MOtor s~haft is inserted through the insulator during as-16 ~ ~a~ ~ o~f the armature. The positioning tongue according to the 17 invention is preferable to, for example, a boss formed on the ar-18 mature insulator in accordance with the prior art, because the in-19 sulator with fiuch a tongue is easier to produce and because the c~ss~b/ jnq tongue is less likely to be broken of~ during ~sKe~bieg~or handl-221 ing. Furthermore, the tongue i~ so located on the armature insu-lator that its radial arms do not ~uffer any substantial decrease in strength.
24~ FIG. XS illustrate~ another method of ~e~blyln~ com-261 mutator segments with the in~ulator 58. The reference numeral 150 26 in FIG. 25 denotes a commutator segment blank which has been form 27 ed by punching sheet copper or the like into the illustrated shape.
28 The commutator segment blank 150 comprises three ~e~ment portions 151 which are interconnected at a central portion 150a of the 30blank and at bridges 151d ~oining the 1UgB 151C projectin~ out- ,~

. ..
, :

;S~7 wardly from t}lC ,~o~ment port:ions.
c~ b l ~ ~ q .~ For/~mblag~ the commut~tor ~egment blank 150 i8 3 placed over the co~lutator insulator 58 of the above described ~L construction, and the central portion 150a of the blank is punched l into the center hole 58R of the insulator, thereby removing this 6 central portion and also bending the inner endfi of the segment 7 ~I portions 151 right-angularly for insertion into the in~ulator cen-~
8 ~ ter hole. The bridge 151d joining the lugs 151c are then cut off,~
9 j and the6e lugs are bent so as to engage the periphery of the 1 insulator 5 8 .
11 It is now clear that the motor of FIG. 1 can be as-12 ~embled through a greatly simplified procedure, which can be large _ 13 ly automated iP desired. Although the foregoing description of 14 FIGS. 19 through 25 has been made in conjunction with the particu-l lar commutator 50 of FIGS. 1 and 2, it will be evident that the 16 commutator 50' of FIGS. 10 through 12 can be assembled and mounted~
17 on the motor shaft in a predetermined an~ular position relative to~
18 the armature core in the same manner.
19 It i6 to be underetood that this invention is not to ~ be limited to the precise forms and embodiments as di6closed here-21 j in since they are intended to be illustrative of the principle~ o~

23 the invention. The concepts and principle~ o~ the invention may be e`mbodied in other forms and adapted for other motors of compai 24 rable character. The invention, therefore, is to be accorded the full scope of the claims appended hereto.

' ' ?

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An electric motor of the type wherein a commutator comprising a plurality of segments is fixedly mounted on a rotatable shaft within a casing having an end cap, with the commutator segments having surfaces arranged in a plane normal to the axis of the shaft, comprising: (a) a plurality of brushes each integrally made of sheet metal, each said brush comprising; (1) a first portion affixed at one point thereon to said end cap; (2) a second portion connected at one end to said first portion and generally extending radially of said end cap past said first portion; and (3) a contact formed on another end of said second portion, said second portion being angled with respect to said first portion whereby said contact is resiliently urged into sliding contact with said surfaces of said commutator segments; (b) means on said end cap for engaging each said brush so as to lock same against angular displacement about said one point on said first portion there-of; and (c) said second portion of each said brush having a notch formed in said one end thereof for engagement by said engaging means on said end cap of said casing.

2. The electric motor as set forth in claim 1, wherein said second portion of each said brush is substantially in the shape of a ring surrounding said first portion thereof.

3. The electric motor as set forth in claim 1, wherein said engaging means is a V-shaped protuberance formed on said rim of said end cap for engagement in said notch in said second portion of each said brush.

4, The electric motor as set forth in claim 1, further comprising: (d) a plurality of terminal members mounted on the outside of said end cap of said casing; (e) there being a plurality of holes in said end cap; (f) there also being a hole in said first portion of each said brush; and (g) a connector in the form of a cylinder of electrically conducting material passed through said hole in said first portion of each said brush and through one of said holes in said end cap, each said connector being connected at one end to one of said terminal members and having another end clinched to secure said first portion of each said brush to said end cap.

5. The electric motor as set forth in claim 4, wherein each said connector is formed integral with one of said terminal members.

6. The electric motor as set forth in claim 1, further comprising means for bounding a lubricant reservoir on part of said surfaces of said commutator segments, said lubric-ant reservoir being adapted to hold therein a lubricant for lubricating contacting surfaces of said commutator segments and said brushes.

7. The electric motor as set forth in claim 6, wherein said bounding means is an arcuate ridge formed on said surface of each said commutator segment, said arcuate ridges on said surfaces of said commutator segments being so arranged as to represent in combination a discontinuous ring.

8. The electric motor as set forth in claim 7, wherein said ridge on said surface of each said commutator segment has a flat top adapted to make sliding contact with said contacts of said brushes.

9. The electric motor as set forth in claim 1, wherein said contact of each said brush is formed by embossing the sheet metal so as to form a cavity on its back, said cavity being adapted to serve as a lubricant reservoir for holding a lubricant therein and thereby for lubricating said contact.

10, The electric motor as set forth in claim 9, wherein in said lubricant reservoir of each said brush has an open or recessed end through which the lubricant is permitted to flow onto said contact.

11. The electric motor as set forth in claim 10, wherein said brushes are so arranged as to generally extend horizontally when the motor is installed in a prescribed up-right disposition, said recessed or open ends of said lubricant reservoirs being disposed opposite to said shaft.

12. The electric motor as set forth in claim 1, further comprising: (d) a rim on said end cap adapted to fit in an open end of said casing; (e) there being at least a pair of notches in said rim, each notch having a pair of divergent surfaces defining same; (f) there being at least a pair of slots formed in the open end of said casing so as to be in register with said notches respectively; (g) said casing having a pair of corners on opposite sides of each said slot which are bent down into one of said notches so as to engage the respective divergent surfaces defining same, whereby said end cap is locked in position at said open end of said casing.

13. The electric motor as set forth in claim 12, wherein said end cap has a flange projecting outwardly of said rim, and wherein said notches extend into said flange.

14. The electric motor as set forth in claim 1, further comprising: (d) an armature core fixedly mounted on said shaft; (e) a pair of armature insulators mounted on said shaft and secured to said armature core at its opposite ends, each armature insulator having a hole for receiving said shaft;
(f) one of said armature insulators having a positioning tongue formed therein a pair of parallel spaced slits extending radially from said hole, said positioning tongue being adapted to be held at least partly raised away from said armature core by said shaft; and (g) a sleeve fixedly mounted on said shaft next to said one armature insulator; (h) there being a recess in said sleeve for receiving said positioning tongue of said one armature insulator whereby said sleeve is disposed in a pre-determined angular position relative to said armature core;
(i) said sleeve including positioning means for engaging said commutator whereby said commutator is disposed on said shaft in a predetermined angular position relative to said armature core.

15. The electric motor as set forth in claim 14, wherein said one armature insulator includes a plurality of radial arms, and wherein said positioning tongue is in align-ment with one of said radial arms.

16. The electric motor as set forth in claim 15, wherein said commutator segments are carried by a disc-like commutator insulator having a center hole and an eccentric positioning hole therein, wherein said sleeve has a flange on its end away from said one armature insulator, and wherein said positioning means of said sleeve is a boss formed on said flange of said sleeve, said boss being adapted to be inserted into said positioning hole in said commutator insulator.

17. The electric motor as set forth in claim 16, including a commutator core in the form of a hollow cylinder of electrically insulating material having a flange on one end said commutator core being fixedly mounted on said shaft and having another end tightly inserted into said sleeve through said center hole in said commutator insulator, whereby said commutator segments and said commutator insulator are caught between said flanges of said sleeve and said commutator core.