US2608807A - Precision hole grinder - Google Patents

Description

Sept. 2, 1952 A. NILSEN ETAL 2,608,807

PRECISION HOLE GRINDER I Filed Nov. 17, 1949 2 smams smzm 1 H62 We I E 5; T 8

INVENTOR:

- ARN E N ILSE N are; K2L R0122 ATT'YS Sept. 2, 1952 A. NILSEN ET'AL PRECISION HOLE GRINDER 2 SHEETSSHEET 2 Filed NOV. 17, 1949 FIG. 7

' INVEN TOR:

ARNE NI N KARLRO R wrciw ATT'YS Patented Sept. 2, 1952 PBECISIONHOLE GRINDER.

Arne Nilsen and Karl Rohrer, Chicago, 111., assignors to Onsrud Machine .WorksyInc, Chicago, -Ill.,- a'corporation of Illinois v Application Novemberll', 1949,Serial-No. 127,832

Y 1 This invention relates to high speed hole grinders and particularly to the construction of a motor unit therefor, whereby the device as a whole may be mounted on a spindle for use on jig borers, vertical and horizontal milling machines, boring mills', lathes, surface grinders, internal grinders, drill presses, shapers, etc, for precision grinding operations requiring a gymtory actionof the grindingwheel. r I

' The main objects of this invention are to provide an improved high speed, motor driven tool foruse in precision hole grinding; to provide such a devicethat may be mounted as a self-contained unit on a boring and facing head haVingtransverse slideways for lateral or eccentric adjust-' ment ofthe toolrelative to the mounting head axis;i .to provide an improved construction for such a grinding unit; to provide a high speed grinding. unithaving fan-improved mounting arrangement for the driven" shaft or' spindle; to provideanimproved motor unit housing that is freely-rotatable independently of both'the motor shaft "and the mounting head; and to provide a motor driven grinding tool unit having an proved suspension arrangement for independently rotatablemotor and housing components. I

A specific embodiment of this invention is shown in the accompanying drawings in which; Figure 1 is a perspective view showing the improved grinding tool and illustrating its mode of operation. e f

Fig. 2 'is a vertical sectional view of the same.

showing its internal construction.

3 is a sectional view of the same, taken on line 3-3 of Fig. 2, showing the bearing relationship for independent mounting of the motor shaft and the rotatingportion of the unit housing.

- -Fig. 4'is a sectional view, taken on line 44 of Fig. 2, showing the 'air inlet for an air wheel or rotor to drive the motor shaft.

*Fig'. 5 is a sectional view, taken on line 5-5 of Fig 4,'showing the disposition of the airwheel rm e k 'I.

Fig. "6 is a' sectional view, taken on line 6''6'of Fig.2, showing one face of the air turbine "rotor which drives the motor shaft. I

Fig; 7 is a fragmentary sectional view, taken on' line 'll'of Fig. 6,showing the shape and arrangement of the air turbine rotor blades; and l-Fig. 8 is a sectional view, taken on line 8-8 of -Fig. 2, showing the arrangement and location off the air- 'outlets'yon the discharge side 'of the turbinero'tor. j ggn the farm show'r'f-in'the drawingsthe invntion' i's embodied in 'a construction havi g a com:

5 Claims. (CL 51-245) pressed-air driven turbine type of motor intended foroperation under approximately pounds per square inch air pressure at a' speedof 50.0.0.0 R. P. M. The turbine rotor is mounted directly on the motor shaft or unit spindle, which pro.- jects from the unit housing at oneend, and the assemblyis suitably supported withinthe housing for operation independentlyof the housing position or motion. The unit as a whole is adapted to be mounted by one end on a tool :head having. a radially adjustable slide, such as the Chandler boring and facing head described in United States Patent No. 2,356,651, issued August 22, 1944, to G. A. Chandler, whereby the axis of the unit may be shifted radially with respect to the axis "of the tool head to provide a gyrating motion forthe grinding wheel'upon rotation of theitool'head by any suitable machine. I v As shown the tool head comprises a cylindrical body I mounted axially on the flange. 2 of ashank 3 which in turn is adapted 'to be received and held'in a suitable chuck, not shown, carried by the rotary spindle of the principal machine; The body I is provided with suitable dove-tail slideways 4 onitsfouter or lower end and'an adjustable slide 5 is mounted in the slidewa'ys for transverse or radial movementiwith respect to the tool head axis. Suitable means, not shown, are provided within the body I to effect micro metric adjustment of the slide 5 andtoholdthe slide in whatever position it might be set; and suchmeans are preferably adapted for operation while the body [is in rotation'as described in the beforementioned Chandler patent; The present invention, however, does not concern the :form or operation of the tool head and that unit, therefore, need not be further discussed.

The present invention is of an independent motor unit, adapted to'be mounted by one end on a rotating head, characterized by a unit hOllS-r ing which is independently rotatable relativeto both the mounting means. and the motorshaft;

and in: the form shown inthe drawings the improved motor unit comprises a pair ofannular end bells or end members 6 and 1 and a cylin'-. drical housing .8 disposed between the end bells, the end bellsor endcaps and the housing'assema bly enclosing a rotor 9x-mounted fast ona;shaft I0 whichin turn is journaled within and extends axially through the housing8. I

The end bell or cap member 6 at the. upper end "of the motor unit is adapted to be suitably mounted, rigidly, on the adjustable slide" 5. of the tool head-assembly 'in such a man'neriithat the shaft-1,0 extends axially relative: to the Taxis-bf having innerrandiouter' races andl-is designed so that its outer race-has a-close fit-withinthe coun-- terbore I3. The inner race of the bearing I4 is adapted to be clamped fast to the upper end of the shaft I I! by means of a clampingenut. I5,"

threaded onto the shaft, the shaft having a reduced end portion to receive thebearingarace and-1 to provide a shoulder against which 'thefiraceqsi seats. The counterbored portion I3 is -alsointernally threaded at its upper. end to.,-receive.-an;- externally threaded plug or closure I6, which hasv an axially extending collar I'l adapted to-sur--- round the nut I 5 and bear against the outer race of itl-ie'bearingvl dato" holdfitfixedlyand; firmly in plaiefwithln the end belllbodyk" Thus; itwill be,

seen: that,--- in the verticai .1 position shown', the shaftilfl is hungnfrom: andsmain-lyisupported by, tlfbearing Miandrthe upper cap member onend b'ell fig thebearing I4 beingjdesigned: to carry, a thrustfl'oadsin either :axial -direction.:..

The housing: 8 is; a uhollowz cylindrical shell, of

s'ubstantiallythe same-:diameter asthetop cap;

or bell member: 6 ,xhaving: a transverse partition" leaeas mwer rend-.4, The'siderwallbfj-the housin is outwardlyc-spacedi from and? encloses; the hub I.I' offtliaendzbell' 6, .anctalso 1 enclosesa double row preloadedcballlibearingi: interposed between,

the housing and thegcoilarjl by'means .of which the housing v:8: isa'support'ed' :from thee-upper; end

bellr'as: Willi be: hereafterr describe'd; The lower; end bell I is a cup-shaped;membeni-adapted, to;

befifittedzomand;secured: .toi. the: partition; I8-,:at

therlower: end". ofitheshousing '8 ,i as; by; means-10ft screws: I 9*; and .is :providedwith; a central opening'fllh: through .iwhich ;;the shaft I I! f extends Asshown: the; interior :of; the cup .shape d;.endr hell 1 isformedatm enclose-the;rotor 9 by which ,the shaft::I 0 lis'edriven; Theilower: end of the.- end1 bellr'ltisioounterboredzaswat 2| to receiverag-radial of -the chuck-:2 It; the "nut 2.5: being :threadediontd thelower end of the shaft Illo'n accordemcei'with' the usual practicez It will now be seen-that-theendbellil and the liciusing 8'iare so 'assembled as to. act as: arlunit and that the bearing' n serves -mainly toz keep the shaft l Il centered Sonv thexhousinguaxis; alitliough it" will be understood that: some: vertical ofaxial -support'for-the shaft lll isialso'iprovided by-f' tlie bearing' 2Z -WhiCH' "i-S) adapted: to? carry; a thrust load:

- before mentionedyf the: housing: and;: the rower end belrassembly of: the mOtOIE'IiHitIiSSUQT ported rrom the :upper end bell 16 by a3 preloaded bearingwhich-"is disposedib'etweemthehousing side wall and the central; hub-il I-;?of:the-upper end::.bel1;'; This bearingtriszof aitype adaptedito an axial-.thmst;loadr-inqeithen--directi0n as zwelli asaradialtloiad; and; in thezform shown; the bearing: :double: row ballrcnnstructionzrin whichetheiirmenrace- 2 I; is nmuntediast omthe 4 outside of the hub II by a tight drlve fit, and wherein the outer race 28 is mounted in the housing 8 by a drive fit within its axially extending side walls. This bearing is preloaded to obviate axial or radial play beyond that only necessary .to permit rotation, and, since the inner race is fast to the end bell and the outer race is fast to thehousing shelligit willtbelseen ithat the housing'shell. and-lower end bell assembly --is hung from and carried by the upper end hell 6 in such a manner that the motor unit as a whole is held-together as an operable assembly while, at the same time, the housing and lower end bell assemblywisindependently rotatable with respect to the: upper endgbell or cap member 6, which vin'tu'rnismounted fast to the slide 5 and the Y tooLhead,

With this manner of assembly, the motor shaft Illi-is rigidly supported in exact axial alignment with the motor unit and is, therefore, freely rotatable at extremely; high speed for. precision p ration wi hout any possibility" f; whip .01: $ral=. th1Z0W- A150,- t e..- housing assembly ds freely rotatable 1 independently of the, shaft; ID,

and; the upper; end; bell 6.. by; which the motor uni-tfis mounted to the;tool head; and regardless of any: movement thatcmightbe imparted -;to the motor unit ,by-thetooliheadu 7 Also, since the houslng-assemblyland,the motor. shaft are both hung from and directlyxsupported by the upperend bell. the axial relation of the shaft andhousingds: maintainedconstant so, that ther le ranca r sp cing ofa he. ro r; 9, between the artition. I B -.and. thedoyVer end. hell ,1, wil remain fixedundenallconditions of operation,

In: the; form. shown; the 1101 01;- 9 .-by which the shaft. l0; isqdriv n. is ,in thei form ofa aint ine wheel haying a. ;plurality of. peripheral bladesv orrbuckets againstwhich a ,str'eambf, airQuhder. pressure; maybe; directed; to impartrotation..- Air. is suppliedt-to, the, ,motor, housing. .by means ,of. a.--flexible connection-.19 which extends 3 into; the sidewall of, the -housing in the. planeofj the par, tition .portion .1 'I 8;; the conneetion. 29, communi eating with a passa e ,3 I} ,in the partition I 8;whioh leads to av downwardly inclined passage; 3! disposedztangentially with -respect= to the face: of the-rotor 9,.and ,which. terminates, at, the :bottom face of the partition 1 I t just. above the annular row-oflbladeslor-buckets .32., The passage 3| which serves as the; air nozzle for; delivery of.,-the air; .under; pressure -to the turbine wheel 9, isjnclined relative;to thefnpper faceof;the-turbina wheel :at;an, angle .otsubstanal v zll de rees; 7 and-.- sincee the turb erwheelvflr p den r otatab e-:-Wi h respect to. the. housing :of. the :motor unit.- aa ndr ven aga st thaturbineibladesfiz rwilli ausethetur i Whe srtoerotatee and: ther bnd iv the shaft. -10! As shown in Fiss..: 6;and 17,-, eitxur jnemadcs -'.buck.et$; are rmedaaroundl. he Outer margins-of the r tor fi;and iust;inside the pe sh: ery thereof, so that the air passages betweenjjhe bladeszBL-extend; fromiace to -,f-a eQf r.the;rotor 9 ndare'op n hem ndsiimlit Th stth a pass n thr u be we n-th :.turhme: lades cannot escape 1 ma sidewise; or radial; direction nd thee: axi umanr sures. ector: th treamz;. xerted@aea nstl the.- turhi. litla es- Theseopenings 3; th1;oug h -the rotor onturbine 9-.--are-formed::in:.the-;- otor;by dri l nez neularly. pa ed holes/into;-each:-faQe1:0i5-the:d' 1? r at an angle of 45 degrees with respect to tha faceof; a'rfl oz'ea d'zf-rem opposite-directions o t a hems aeefi Wi lamette-seabed:withlaamslndsd.

angle of 90'deg 1 'e es. .In order to provide a smooth rounded contour for the wall of the passage, .on the side thereof it'owardthe direction of rotation of the rotor 9, the passages are drilled by m'eans of a 'drill' having a rounded tip as indicated by the dotted outline in 7.

In order to provide for the final di'schargeof the air which drives the turbine wheel 9, the end bell! is provided with anannular channel 34' located directly belowthe annular row of turg. bine blades, and a plurality. of discharge openin'gs 35 are provided to lead from'thefchannelfia to the outer. surface of the end jbell 'l; These discharge passages 35 arepreferably locatedop posite the incoming air nozzle; l and several are provided to' assure rapidtdischarge of the air after it has passed through theturbine blades and to obviate the buil ing up ofback pressure inthechannel 3'4. 7 1 1r With this type of powerwheel or rotor for driving the motorunitshaft ;l 0, the speed of the shaft willbe governed to a large extentfby the pressure of the air that is used'to drive the rotor;

In practice, the motor unit is designed tofoperate at'a speed of fiftythousand revolutions per min ute under an actuating air pressure of 109 pounds per square inch; a particular advantage of this form of ,drive being that such a high speed can beobtained with a relatively small air consumption.

In the operation of the device, for the precision grinding of holes or any other internal grinding operation, the tool head shank 3, is mounted in the chuck of a suitable rotating machine, such as a drill press, milling machine, boring machine or the like, whereby the grinding unit as a whole may be rotatedr'The grinding stone 35, is, then mounted by its shank-in the chuck 26 0.1, the grinding unit; and the slide 5 is lateraIIyofE-set with respect-to'the'axis' of the shank 3 so that the -periphery of the grinding stone will engage the'rough surface of the hole or opening-thatis to'be ground, which opening ig of cu1iSe,.Q6ntered on the axis of the shank 3. The "toolhead is then rotatedgso; that grinding unit is gyrated in a circle thatwillcause the periphery of the grinding stone to follow the periphery of the opening that is to'be ground.

-This, is' illustrated in Fig. 1 wherein the slide is shown off-setlaterally ,and wherein the arrows 31 indicate the gyratory path of the grinding stone for finishing the surface of an opening 33. Thus, while the grinding unit is gyrating so that the stone will follow the path indicated by the arrows 31, the grinding stone 38 will be driven at high speed by the motor unit shaft I9. As the grinding stone works on the surface of the opening 38, the slide 5 is gradually shifted in an outward direction to increase the size of the circle of gyration until the opening being ground has reached the precise diameter desired.

The mechanism for shifting the slide 5 while the tool head is rotating, is not herein shown or described since it forms no part of the present invention and a suitable mechanism for this purpose is disclosed in the before-mentioned United States Patent No. 2,356,651.

The housing assembly, comprising the body" 8 and the lower end bell 1, provides the reaction means for the force which drives the rotor 9 and, since the housing is free to rotate relative to the primary supporting end bell 6, it is necessary to provide some suitable restraining means to prevent free turning of the housing, in the direction opposite the rotation of the rotor, which at the same time will permit the housing to gyrate mounted, or a rigid arm extending from the unit housing into slidable lateral engagement with a fixed abutment. As shown in Fig. 1 a rigid arm 39, projecting laterally from the housing Bf, is in'- dicated as a restraining means and it will be understood that this arm slidably engages a fixed portion of the machine, which carries and drives the tool. head I, so as to preventrotation of'th'e h u n i, 7 Q h I V The main advantages of this invention reside in the simple and sturdy arrangement of the grinding unit components whereby the housing and the driven motor shaftare each rotatably and independently mounted on an end bell which in turn, serves as a primary support for the unit assembly, and in the bearing arrangement whereby the housing body ofgthe unit isfreely rotatable with respect to the end bell andthe motor shaft and is yet suppo'rtedand held in axially fixed relation with those parts. f Other advantages of this invention are to be found in the construction wherein the unit housing may be held against rotation," even thoug'h the unit is mounted on a rotating fixture, thus permitting a direct, non-rotating, connection between the housing and thepower source; and in the construction of the unitassembly whereby a very high speed may be imparted to the motor shaft without anyidanger of whip or misalignment occurring in the grinding wheel spindle,

Although but one specific embodiment of this invention is herein shown and described,.it will be understood that details of theconstruction shown may be altered or omitted without departing from the spirit of this invention as defined in the following claims, We claim: l. ,A motor unit comprising an end bell adapted to be mounted rigidly'on a rotatable support and having an integral outwardly projecting hub, said hub having a. .centralaxial bore; ;a hollow housing surrounding saidhuh 'andha ing its side wall spaced-radially therefrom; Tab g having radially spaced inner andlouter .rac's,

and capable of carryinganaxial thrust in both journaled in the bore of said hub; a rotor enclosed by said housing and cap member and fast on said shaft; bearing means in said cap member spaced axially outward from said rotor for holding said shaft in axial alignment with the central bore of said hub, and means within said motor unit for driving said rotor, said housing being independently rotatable relative to said end bell and said shaft.

2. A motor unit comprising an end bell adapted to be mounted rigidly on a rotating support and having an integral outwardly projecting hub, said hub having a central axial bore; a hollow housing surrounding said hub and having its side wall spaced radially therefrom; a bearing AQQQQQZ' f said ou ing;-aca ime nh n a n he 015 said -housing axially opposite said end t1 ethrougdaXiaHy aligned'with bore of 1 said 23 kaz-v e e di a a th u h sa hennaanqi o theb i o d u a adial hfiQfiPQQWQWQW t m d; 1 1 1' i lsa d shaft radially, said bearing being secured ,tqsaid shaft to sugport the samev against axial notion ad ptedto lbe imou nted rigidlyon a rotating sup:

nor-fend having an integral axially extending entra-l hub, said hub having a central axial gassage a rotatable shaft extending axially from said-hup-and having oneend journaled in a male heari g i q d in d, as ag n adapted; carry axial thrust for holding said shaftagainst axialmpvement, a cup-like housing haying its side, wall spaced from and surround! ins said 1 11 a o ed a l bear n d s: posed, between said hub and said housing and haying inner and outer races. respectiyely secured tosaiihubiand theihonsing side wall, said bean ing heing adapted to carry an axial thrust load nd i ppq r aid housin n nax a ct on while permitting the same to rotate independ ntl p sai lhnb, arin meansmo e n sai iaisin e ond tha nxl 70 a dh b r in said shaft aligned with theagds o f ,s aid hub, and means enclosed within said housing for driying aisi11ai -l ma viceg t e c a s d bed! h o hi n with a rqtatable tool head of. a motor unit extending axially therefrom and having an endmernher rigidly secured. to said head for tqtatisznj erewit ho m u on nd eggtending axially from said end member, said housing heing journaled on said end member for independent rotation i elative thereto: and on the afisfthereqt a shaft extending axially through s enelosedbyisaid housing and pay member housing and fixed o sa d s aft, and; a; c ndu t connection on said housing and leading to L-said, r 1 9: ion u c Q fiu. d essure vm pp ib adev ce of the dessr bedi amQtQrun t: c mp n and mai ba ha a mars 50 1 mountin heisame, ri id. on a rotatab e,$90. -v i ad. and h v ng an; ia ly exte din hqllon hub cylindrical ousi g? henna-a. ida wallv eififi l g axia ly mm said endmwbenandsu: roundin said, ub,.- a d h us ne being ,rq atablg me nted-on. th out r: Side lott aidv hub, anemia-A- p ed radv li earinemeans adantedfito carnyan. ax a hl: -1 ad, aid bear ng ans hay n nner a d ou e ra es espeqtiv y secured on said hub and on the inside of said hgusing side wall, a ro a ab e, hafti xtending ax a ln throu h sa d1housing and i to. sa dhnbkh n ng means m nt d n; a d. ub a d a d ,hqusin irespeqz finely q s orting sa dr shaft. m tor means hini hpu n or d i in said ha t .and meanson, sa d.- -hous ng leading to said mom; mean f fi ed. nnec i n: h Q ?9 41 QW r thexefg i;

REFEBENQES Thefollowing references are:.of reeord imtho file ofthis; patent;

UNITED straws-PA E T Number Country Date 315,955 Germany g Nov. lfQlSlQ 857,704 France Apr. 22 1 90 ,09 vde m r zalaiz 91 Gleatfi iili m

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