US2616336A - Apparatus for producing varying speed gearing - Google Patents

Description

Nov. 4, 1952 J. H. HOLSTEIN 2,616,336

APPARATUS FOR PRODUCING VARYING SPEED GEARING Jhl/G/I Iior Nov. 4, 1952 J. H. HOLSTEIN APPARATUS FOR PRODUCING VARYING SPEED GEARING 4 Sheets-Sheet 3 Filed March 11, 1947 Nov. 4, 1952 J. H. HOLSTEIN APPARATUS FOR PRODUCING VARYING SPEED GEARING 4 Sheets-Sheet 4 Filed March 11, 1947 Patented Nov. 4, 1 952 APPARATUS FOR-PRODUCING VARYING SPEED GEARING John H. Holstein, Fresno, Calif assignorto Goodman Manufacturing Company, .Chicago,

Ill., a corporation of Illinois ApplicationlMarchill, 1947;Serial.No.. 7*38,8-39

Claims.

This invention relates to improvements in apparatus'for producing varying speedgearing.

An application SerialNo. 702,724, filed by William W. Sloane on October 11,. 1946, and entitled Improvements in Gearings, discloses a new and novel form of varying speed gearing in which the speed variations are :attained .by modifying :the gear teeth. so the pinion teeth :maycontact the gear teeth along contact lines which cross the common center line of the gear and pinion at varying points with respect to the tips and roots of. the'teeth of the-gear and pinion. With'this form of varying-speed gearing, varying speedsets of gearing may b produced withroundgearand pinion blanks and aconcentric pinionhaving a standard tooth form-,and with a round pinion blankhaving .a standard'tooth formandmounted eccentricaily of its center, and an irregularly shapedgear blank, asmayclea-rly be understood with reference to the aforementioned Sloane application.

A more specific object of. my invention is to provide .a .new and novel device for adapting a hobbing machine to.generate varying speed gears of the foregoing types in a'continuous operation.

In carrying out my invention I mount-a barrelshaped hob on the hob-spindleof agear hobber the. cross contoursof the teeth of whichare identical to a'segmentof the pinion. which is to drive the finished gear. I also mount a gear blankon'the work spindletof the hobberfor relative. movement with respect thereto, .and'where the varying speed'gear. is .to bedriven by apinion mountedv eccentrically of its center .I mounti:.the gear blank on an eccentric having the :same eccentricity as the pinion which will. drive the finished gear .and rotate the. eccentric in one direction at a constant speed corresponding -to the speed ofv the eccentric. pinion which will drive the finished gear, and rotate the. gear blank in an opposite direction at .a varyingspeed corresponding to. the. speed of rotation of the finishe'd gear, so the :speed. ratios between the eccentric and gear blank. .will.,;be the I same as th varying speed ratios atiwhich thefinished gearand'pinion are to. operate.

An: application Serial No. 711,745, filed-November 22,1946, by .Emil..J..Hlinsky, relates to a method and apparatus 'for producing varying speed gears of the type. disclosed in theaforementioned Sloane application. The apparatus of my present invention differs from. that disclosed in the foregoingfHlinsky application, howevenin that in the Hlinskyapplication the cutter rotates about; anaxis eccentric. ofits center when generating a varying speed gear of a type which is adaptedtobe .driven by arr-eccentric pinion. In m epresent invention the cutterv always rotates about. an axis concentric with its center and when a gear of a type whichis adapted 'to be driven byan eccentric pinionis being generated, the ear blank vmoves translatively with respect to its cutter .as-saidgear blank rotatesduring cutting so that said gear blank and the periphery of .said cutterfwill maintain the same relative positions withrespect to each other duringcutting as. are maintained bythefinished gearrunning with its. eccentric, pinion.

.These andother objects of my invention will appear from time to timeasthe followingspecification proceeds and with reference to theaccompanying drawings wherein:

Figure .1 isa transverse sectional viewtaken through the work spindle of a gear hobbing machine -having mechanism for adaptingthe machine to :cut a varying speed gear -in. accordance with my invention embodied therein;

Figure .2 is .a fragmentary .view of the work spindle lookingtowards. the hoband showingthe gear blankintransverse section, and showing certain of the parts for supporting the gear blank on the work spindle and for driving the gear blank from. the work. spindle, broken'away and in-section;

.Figure 3 is anenlarged plan view looking down on the wo-rk spindleof. thegear. bobbing machine, showingthe completed. varying spee'dgear on the wor-kspindle and showingcertain parts of the hob and support for-the .hob spindle broken away andin section;

Figure 4 is asectionalview taken substantially along line 4-'4 of Fig-lire. 1;,

f igure 5 isa'diagrammatic View showing the positionof-thegear blank with respect to its eccentric when, theaeccentric is in one extreme position; and

Figure 6 is a diagrammatic view showing the position of the .gear blank with .respect toiits eccentric; when the eccentric" is in. an opposite extreme position from that shown in Eigure15.

.Inthe drawings 'l shave' shown apart of a main platform and housing II), a vertical WOIfkT'SDil-Idlfi H, and aqhob spindle: 1-7. of a gear bobbing machine. *Said gear .h'obbing machine may be of any wellknown formzandis no part of my presentinvention soisonly herein shown insofar as is; necessary-to make my presentinvention readily understandable;

Thechob spindle l-2 has-a hob 13 mounted thereon. S-aidhob is of a substantiallybarrel- 3 shaped form having teeth l4 cut on a helix with the cross contours of said teeth identical to a segment of the pinion which is to drive the finished gear, as shown in Figure 3, to more accurately generate the varying speed gear and assure that the hob will not cut off the tips of the teeth of the gear where the contour of the gear blank is irregular. Said hob spindle is shown as being set at an angle to the gear blank that corresponds to the helix angle of the hob at its pitch line and is mounted adjacent its ends on a head frame- [5 guided in a vertical guide standard I 6, adjustably movable along the platform I 9, towards and from the Work spindle ll. Said frame is vertically movable along said guide standard for feeding said hob across the face of a gear blank I? during the cutting operation, in a manner usual with gear generating machines of the hobbing type.

The work spindle H is:- rotatably mounted in the housing and platform "I0 of the hobbing-machine and forms a support for the gear blank I! on an arbor l8. Said arbor is detachably secured to a work table [9 on the top of a flanged portion 23 of said work spindle, as by bolts 2!, the heads of which are mounted in diametrically extending T- slots 22, 22 formed in said work table and herein shown as extending at right angles with respect to each other. An index gear 23, herein shown as being a worm gear, is keyed on said work spindle adjacent its lower end (see Figure 1). Said worm gear is driven from an index worm 24 at a speed synchronized with the speed of rotation of the hob l3 in a manner well known to those skilled in the art and no part of my present invention, so not herein shown or described.

A vertical shaft 25 mounted for rotation with respect to the spindle I I is herein shown as being journaled within said work spindle, coaxial with the axis of rotation thereof, and as projecting upwardly therefrom above the gear blank I! and arbor l8. Said shaft is journaled adjacent its upper end in a bracket 26, which may be vertically adjusted along a standard 61, to permit insertion of the gear blank I! thereon and removal of the finished gear therefrom. Said shaft is journaled intermediate its ends in a flanged collar 21 mounted adjacent the upper end of said work spindle and is journaled adjacent its lower end in a depending hub 28 of a cage 29 of a planetary geared reduction device. Said hub is keyed within a cylindrical boss 3| projecting upwardly from the base of the hobbing machine. A sun gear 32 of said planetary geared reduction device is keyed on said shaft, for driving said shaft from said Work spindle. The hub of said sun gear is journaled in a flanged collar 33, herein shown as being threaded within the lower end of said work'spindle and as depending therefrom. Said sun gear meshes with a plurality of planetary pinions 34, 34 on vertical shafts 35, 35 mounted at their opposite ends in the cage 23. Said pinions mesh with and are rotatably driven from an internal gear 36 extending inwardly from a drum 3], herein shown as being threaded on and rotatably driven from said work spindle l I.

Said planetary is herein shown as being arranged to step up the speed of rotation of the vertical shaft 25 and drive said shaft from the work spindle H at twice the speed of rotation of said work spindle in a direction opposite to the direction of rotation of said work spindle. The speed ratio between said shaft and the gear blank 17 should be the same as the speed ratio of the 4 finished gear and pinion. As for example, where the average speed reduction between the finished gear and pinion is a 2:1 reduction, the shaft 25 will rotate at twice the speed of the work spindle l I and in a direction opposite to the direction of rotation of said work spindle; where the average reduction between the pinion and gear is a 3:1 reduction, the shaft 25 will have to rotate at three times the speed of rotation of said work spindle; and where there is no speed reduction said shaft will rotate at the speed of rotation of said work spindle.

An eccentric 33 is keyed adjacent the upper end of the shaft 25 just beneath the bracket 26. Said eccentric is of a cylindrical formation with a closed top except for an opening to receive the shaft 25, and its walls extend downwardly along a bearing 43 mounted on the arbor 18. A work supporting mandrel 4| is mounted on said eccentric for rotatable movement with respect thereto and is abutted by a shouldered upper portion thereof. The inside of the top of said eccentric abuts a shouldered portion of said shaft and said eccentric is held in position on said shaft by means of a nut s2 abutting the top of the closed portion of said eccentric.

Where the finished gear is to be driven by an eccentric pinion, the eccentricity of the eccentric 39 is the same as the eccentricity of the pinion which will drive the finished gear so that the position of the gear blank I! will be varied with respect to the hob E3 in a manner identical to the operation of the finished gear with its eccentric driving pinion. The mandrel M has the gear blank I! detachably mounted thereon as by cap screws 43, 43. The mandrel 4| is slidably supported on the top surface of a spacing plate 44 and is guided for diametral movement with respect to said plate by means of two aligned feather keys 45, 45 mounted on the top surface of said spacing plate 44 on opposite sides of the axis of rotation thereof in keyways 56, 45. Said keyways are formed in the top surface of said spacing plate and are intersected at their longitudinal center by a common diametral line intersecting the center of the shaft 25. Said feather keys slidably engage keyways 4T, 4? formed in the bottom of said arbor, to rotatably drive said arbor, but to permit movement of said arbor across the face of said spacing plate in one direction. Said spacing plate in turn rests on and is driven from a driving plate 59 driven from the arbor 48 at a varying speed in a manner which will hereinafter more clearly appear as this specification proceeds. Said spacing plate is driven from said driving plate by means of feather keys 50, 50 on opposite sides of the center of rotation of the shaft 25 and disposed at right angles to the feather keys d5, 45. Said feather keys are mounted in keyways 5!, '5! cut in the top surface of the plate 49 and intersected at their longitudinal center by a common diametral line intersecting the center of rotation of the shaft 25. Said keys slidably engage keyways 52, 52 formed in the bottom of the spacing plate 4. Rotatable movement of the eccentric 39 will thus rectilinearly move the work mandrel GI and the gear blank I! with respect to the cutting tool or hob E3 to change the position of the center of said gear blank with respect to said hob in the same manner the center of the eccentric pinion which is to drive the finished gear will move with respect to the finished gear, while the gear blank is rotatably driven at a varying speed about the vertical shaft 25 in a direction opposite to the direction of rotation of said shaft.

The meansfor turning-the driving plate 49 and the gearblank H at aspeed which varies in'the same manner the speed of the finished gear will vary when driven by an eccentric pinion, includes a stationary cam 55 mounted on the arbor l8 on a flanged bearing 51 which abuts a lower shouldered portion 59 of said arbor. Said cam has an arm 68 extending therefrom which is secured to the upright standard 6! of the hobbing machine, to hold said cam from rotation. The shape of said cam is such as to cause relative movement of the'gear blank ill with respect to the adapter plate 54 so as to move said gear blank at the varying speed during cutting required to produce the desired varying speed gear, aswill hereinafter more clearly appear as this specification proceeds.

The camtiiis-engaged by a roller 63 journaled on a pivotal pin 64 secured to'and depending from the outer end of a lever arm 65 of a bell crank 66. Said bell crank has a bifurcated central portion, the furcations of which extend along the upper and lower sides of a bracket 61 extending outwardly from and formed integrally with adriving member 69 keyed on the arbor l3 and rotatably driven thereby. A pivotal pin 70 extending through the furcations of said central portion of saidlever arm and said bracket pivotally connects said bell crank thereto. An arm 13 of said bell crank extends inwardly from said pivotal pin along the upper side of said bracket and has gear teeth l4 cut integrally with the inner side thereof. The center of the pitch circle of said gear teeth is herein shown as being coaxial with the pivotal axis of said bell crank. Said gear teeth mesh with gear teeth 75 herein shown as extending outwardly from and as being formed integrally with the driving plate 9 for rotatably driving said plate and the mandrel ll and gear blank I! at a varying speed upon rotation of said arbor l8 and driving member 69. The distance from the contact point of the roller 63'to the pivotal axis of the bell crank 66 is herein shown as being twice the distance from the pivotal'axis of said bell crank to the pitch circle of the teeth 14. Also the angular'ratio between the teeth 74 on the arm 13 of the bell crank 66 and teeth 15 on the plate 59' is hereinshown as being a 2:1 ratio giving a final angular ratio from the roller 63 to the center of the gear blank of 2:1. It should be understood, however, that this ratio is not a determining factor and has been picked for convenience, 'and that various other ratios maybe used if desired.

The bell crank 65 also has an arm 16 extending from its pivotal axis in a direction opposite from the arm 65 but towards the driving member 69. Said arm is engaged by a spring H interposed between the end of said arm and the driving member 69, for holding the roller 53' in engagement with the surface of the cam 55.

The form of the cam 55 may be determined by the movement or displacement of the roller 63 on the end of the lever arm 55 of the bell crank 66 necessary to move the gear blank ll with respect to the shaft 25 at the desired varying speed so the varying speed ratio between said gear blank and said shaft will be the same as the varying speed ratio at which the finished gear and pinion are to operate. The form of said cam may be determined graphically and'mathematically from a speed ratio curve of the finished gear and pinion in a manner well known to those skilled in the art, which is no part of my present invention so is not herein shown or described.

' In the illustrative form ":of :myinvention 311 1 described the varying speed'i'gear fandzpir'iion rotate about axes eccentric o'fitheir'centers. "When, however, it is not desired ornecessary'to have as great a variation in speed as may be obtained from an eccentric-gear and pinion, the'mandrel M and gear blank l1 may be mounted to rotate about an axis concentric withtheicenters of said mandrel and gear blank. said gearblankimay then be rotatablydriven about its .center at-a varying speed which will give the same varying speed ratio aswill be obtained whenthefimshed gear is rotatably driven by its pinion. The shape of the cam which will give therequired varying speed of the gear may be-determined graphically and mathematically fromzthe desired speedratio curve of the gear and pinion in the manner mentioned before and not herein shown or described since it is no part of myinvention. 'The hob'f 3 may then be driven at a'cons-tant speed'of rotation and fed across the faceofsaid gear blank in the direction of the axis of rotation of said gear, to effect cutting.

In generating the varyin speed gear shown in Figure 3 from the gear blank IL-and assuming that said gear blank is mounted 'on the mandrel 4| on the eccentric '39'and the hob |3"is mounted on-the hob spindle I2,'the cutting head l5 may then be moved downwardly along its guides formed in the guide frame It to exposition in close proximity to the top portion of the face of said gear blank. The machine may then be started to rotatably drive the gear blank in'one direction and the eccentric 39 in an opposite direction at a speed which may be twice the speed of rotation of the'work spindle I i, to generate the gear illustrated herein. At the same time, the hob I3 is driven at a constant speed'of rotation which is synchronized with the speed of rotation of said work spindle ll. When said hob and gear blank are both rotating, feeding movement of said cutting head l5 and hob I3 in the direction of the axis of said gear blank may then be started, to commence generating the teeth of the gear by said hob while said ear blank is rotating about the eccentric at a varying speed and said eccentric is rotating in a direction opposite to the direction of rotation of said gear blank at a constant speed corresponding to the speed of the pinion which will drive the finished gear. Feeding movement of the hob in the direction of the axis of the gear blank is continued as said hob and gear blank rotate with respect to each other until the teeth of the gear have been completely generatedacross the'entire face of said gear blank, it being understood that the feeding and generatin operations are done in the manner usual in generating standard tooth form for constant speed gears 'on'gear hobbing machines.

It may be seen from the foregoing that anew and improved method has been provided for cutting varying speed gears on a'gear hobbing machine and that this method is; particularly adapted to cut varying speed gears of the'type which are driven froman eccentric pinion. It may further be seen that this method makes it possible to generate a varying speed gearof the type driven from an eccentric'p-inion'with a gear hobbing machine by transferring theeccentricity of the pinion to the gear by mounting thegear on an eccentric and by driving the eccentric and gear in the same relative directions with respect to each other "as the directions at which-the finished gear andpinionwillrotate "and-at the sanievarying speed ratios at which the finished gear and pinion will operate.

It may still further be seen that by this method oi generating a varying speed gear, a gear may be generated having the desired tooth contour, which may vary for the several teeth of the gear, and that it is possible to generate a gear having a varying tooth contour for the several teeth of the gear by generating the teeth with a hob of a barrel-shaped formation wherein the cross contours of the teeth of the hob are identical to the teeth of a segment of the pinion which is to drive the finished gear.

It should here be understood that while I have herein shown and described my method of generating varying speed gears as being adapted to generate varying speed gears from a gear hobbing machine, that such gears can also be generated from a gear shaper using a concentric pinion type cutter, and using the speed varying and position changing mechanism illustrated herein, without departing from the scope of my invention. Furthermore, I do not wish to be construed as limiting my invention to the specific embodiment illustrated, excepting as it may be limited in the appended claims.

I claim as my invention:

1. In a machine for generating varying speed gearing, a work spindle mounted for rotation at constantspeed, a work support for a gear blank adapted to be driven by said work spindle, a rotating cutter having cutting teeth with a cross section in a plane perpendicular to the axis of rotation of said gear blank over the portion coming in contact with said gear blank consisting of a series of teeth of identical cross section essentially of involute form, said cross section being a reproduction of a portion of a conjugate matching pinion adapted to run with a finished varying speed gear generated from said gear blank, mean for imparting translative movement to said work support and said gear blank in accordance with the varying pitch radius of said finished gear, a cam, a cam follower mounted for rotation with said work spindle and having an operative engagement with said cam, means actuated by the movement of said cam follower in following the contour of said cam for imparting relative rotation between said work spindle and said Work support and said gear blank in accordance with the desired velocities of said finished varying speed gear.

2. In a machine for generating varying speed gearing, a work spindle mounted for rotation at constant speed, a work support for a gear blank adapted to be driven by said work spindle, a rotating cutter having cutting teeth with a cross section in a plane perpendicular to the axis of rotation of said gear blank over the portion coming in contact with said gear blank consisting of a series of teeth of identical cross section essentially of involute form, said cross section being a reproduction of a portion of a conjugate matching pinion adapted to run with a finished varying speed gear generated from said gear blank, means for imparting translative movement to said work suport and said gear blank in accordance with the varying pitch radius of said finished gear, acam, a cam follower mounted for rotation with said work spindle and having an operative engagement with said cam, means actuated by the movement of said cam follower in following the contour of said cam for imparting relative rotation between said work spindle and said work support and said gear blank in accordance with the desired angular velocities of said finished varying speed gear, and coupling means between said work support and said work spindle for afiording such translative movement of said gear blank during rotation thereof on said work support.

3. In a machine for generating varying speed gearing, a work spindle mounted for rotation at constant speed, a work support for a gear blank adapted to be driven by said work spindle, a rotating cutter having cutting teeth with a cross section in a plane perpendicular to the axis of rotation of said gear blank over the portion coming in contact with said gear blank consisting of a series of teeth of identical cross section essentially of involute form, said cross section being a reproduction of a portion of a conjugate matching pinion adapted to run with a finished varying speed gear generated from said gear blank, a cam, a cam follower mounted for rotation with said work spindle and having an operative engagement with said cam, means actuated by the movement of said cam follower in following the contour of said cam for imparting relative rotation between said work spindle and said work support and said gear blank in accordance with the desired angular velocities of said finished varying speed gear.

4. In a machine for generating varying speed gearing, a work spindle mounted for rotation at constant speed, a work support for a gear blank adapted to be driven by said work spindle, a rotating cutter having cutting teeth with a cross section in a plane perpendicular to the axis of rotation of said gear blank over the portion coming in contact with said gear blank consisting of a series of teeth of identical cross section essentially of involute form, said cross section being a reproduction of a portion of a conjugate matching pinion adapted to run with a finished varying speed gear generated from said gear blank, an eccentric driven from said work spindle for imparting translative movement to said work support and said gear blank to maintain the same relative positions between said gear blank and cutter during generation of said varying speed gear as are maintained between the finished varying speed gear and an eccentrically mounted pinion conjugate therewith, coupling means between said work support and said work spindle for affording such translative movement of said gear blank during rotation thereof on said work support.

5. In a machine for generating varying speed gearing, a work spindle mounted for rotation at constant speed, a work support for a gear blank adapted to b driven by said work spindle, a rotating cutter having cutting teeth with a cross section in a plane perpendicular to the axis of rotation of said gear blank over the portion coming in contact with said gear blank consisting of a series of teeth of identical cross section essentially of involute form, said cross section being a reproduction of a portion of a conjugate matching pinion adapted to run with a finished varying speed gear generated from said gear blank, an eccentric driven from said work spindle for imparting translative movement of said work support and said gear blank to maintain the same relative positions between said gear blank and cutter during generation of said varying speed gear as are maintained between the finished varying speed gear and an eccentrically mounted pinion conjugate therewith, a cam, a cam follower mounted for rotation with said work spindle and having an operative engagement with said cam, means actuated by the movement of said cam follower in following the contour of said cam for imparting relative rotation between said work spindle and said work support and said gear blank in accordance with the desired angular 5 velocities of said finished varying speed gear.

JOHN H. HOLSTEIN.

REFERENCES CITED The following references are of record in the 10 file of this patent:

Number Number 10 UNITED STATES PATENTS Name Date Fellows July 11; 1916 Fellows July 11'; 1916 Parsons et al. Aug. 12, 1924 Candee Aug. 15, 1933 FOREIGN PATENTS Country Date Great Britain Jan. 7, 1941

Images