US1746571A - Toothed gearing - Google Patents

Description

Feb. 11, 1930. H, D, WILUMS 1,746,571

TOOTHED GEARING "original Filed July 25, 1914 Si vwewtoz v./Zfnrvy. Williams Patented Feb. 11, 1930 y UNITED STATES PATENT OFFICE HARVEY D. WILLIAMS, OF WALLINGFORD, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, TO SECURITY TRUST COMPANY, OF DETROIT, MICHIGAN, A COR- PORATION 0F MICHIGAN TOOTI'IED GEARING- Original application led July 25, 1914, Serial No. 853,017, and in Great Britain May 6, 1914. Divided and this application filed September 20, 1919.

My present invention, for which I have filed applications in Great Britain May 6, 1914, and in France October 6, 1914, relates to gear wheels, and has particular' reference to that type of gearing in which two succes sive working tooth-surfaces (whether on the same tooth or at the same tooth-space) constitute a pair related in a particular manner to a master-form axis7 located between the two tooth-surfaces of said pair. My invention is designed for use in cases in which one of the meshing gears (hereinafter referred t0 as the wheel) has its working toothesurfaces formed according to a single-reproduci tion configuration, while the other gear (hereinafter referred to as the pinion) has its working tooth-surfaces formed according to a compoundreproduction configuration and conjugate to those of the said wheel. The present application is a division of my application for Letters Patent filed in the United States Patent Oliice on July 25, 1914, Serial No. 853,017, and renewed on December 5, 1917, Serial No. 205,664, on which Letters Patent No. 1,324,287 were issued on December 9th, 1919.

Most of the figures of the drawingsA of my said Letters Patent disclose a form of my invention in which the master-form axis lying `between the two tooth-surfaces of the same pair, on the wheel, is a straight line, so that both surfaces of such pair may be produced in a very simple manner, by the rectilinear reciprocation of a tool the profile of which corresponds to that of a tooth or of a tooth-space. According to the species of my invention forming the subject-matter of the present'application, the two surfaces of the same pair,von the wheel having tooth-` surfaces of single-reproduction configuration, are such as may be produced by the motion of a suitable tool along a curvilinear path, and more particularly, along a circular arc, that is to say, the master-form axis is nolonger straight, but curved, preferably according to the arc of a circle. The present species of my invention was also described andA illustrated in my earlier application above referred to, `at the time of its ling.

-z-.Reference is to behad to the accompanyy adjacent tooth-spaces.

Serial No. 325,216.

ing` drawings, in which Fig. 1 is a partial end view of a spur wheel and a mating pinion embodying this invention; Fig. 2 is a face view showing a portion of the peripheral surface or tooth-Zone of the wheel shown in Fig. 1; Fig. 3 is a partial face view of the tooth-Zone of a bevel wheel formed according to this invention; Fig. 4 is a similar parta?L view of a skew bevel wheel embodying this invention; Fig. 5 is a cross section on line 5-5 of Figs. 2, 3, and 4; Fig. 6 is a cross section of another form of the wheel, taken on the same plane as Fig. 5; Fig. 7 is a perspective view of a portion of a bevel pinion constructed according to this invention; and Fig. 8 is a diagram illustrating certain re'- lations set forth hereinafter; and Fig. 9 is an end view of the tools employed for cutting the working tooth-surfaces on the wheel and on the pinion.

In Figs.'1 and 2, I have shown a spur wheel B having a tooth-zone N across which ex tend the skew working tooth-surfaces arranged in pairs, the two surfaces of the same pair, as f3, f5, being formed of longitudinal circular-arc elements all parallel to a circular-arc master-form axis w13 which lies between said tooth-surfaces and intersects obliquely the two planes at the ends of said tooth-zone. In the particular case here shown, the surfaces f3, are at the saine tooth-space F, and h indicates a portion of the tooth lying in the tooth-zone between two The axis of the wheel is indicated at ma, and the parallel axis of the mating spur pinion P at d, while m designates the instant axis which is parallel to the axes m3 and (l and which intersects the mas ter-form axis w18 at a point half-way between the end surfaces of the tooth-zone, which point lies on` the median pitch-circle 7 of the wheel B and on the median pitch-circle 8 of the pinion P', the latter having teeth g the working surfaces of which are conjugate to those of the wheel, as will be set forth more fully hereinafter. At e, Fig. 2, I have indicated the angle of Obliquity which the mas-- ter-form axis (that is, a tooth-zone secant thereto) forms with the instant axis m.' Inasmuch as the surfaces f3, ffconsist of'curvif` linear' longitudinal elements all parallel to the same master-form axis m13, the latter being a circular arc, it will be obvious that both surfaces of the same pair may be produced at the same time by moving (rotating) in a corresponding circular path, a tool, such as .I (Fig. 9) having the same cross sectional shape as the tooth-space, the shape of the latter being shown best in Fig. 5. The wheel or Wheel-blank would remain stationary during this production of a pair of tooth-surfaces, so that they may be said to be formed according to a single-reproduction configuration. It will be obvious that when the wheel and pinion are rotating in a certain direction, say the one indicated by the arrow i in Fig. l, only one surface of each pair of surfaces of the wheel and of the pinion will be in driving (fo-operation, the other surfaces of such pairs acting simply to prevent backlash. Inasmuch as generally it is desirable to have the gears transmit power equally well in either direction, I prefer to have the two tooth-surfaces of the same pair disposed symmetrically to the central line m2 which intersects the master-form axis see Figs. 5 and 8).

In Fig. 3 I have illustrated a bevel wheel with tooth-surfaces arranged in pairs, the two tooth-surfaces of the same pair having the same relation to each other and to their master-forni axis as in Figs. l and 0. The secants subten ding the tooth-zone arcs of the master-form axes m of the several pairs of tooth-surfaces f3, f5, will, if extended, pass through the apex 0 of the wheel-cone, of which the tooth-Zone N forms part; the secants subtending the longitudinal arcs at the bottom edges of the working tooth-surfaces are substantially tangential to a circle 253, and the secants subtending the longitudinal arcs at the upper edges of said tooth-surfaces are substantially tangential to a circle 1', each of said circles having its center on the axis of the wheel-cone. The spacing of adjacent master-form axes m is uniform, as indicated by the angle or arc Z, but-owing to the forniation on the tooth-surfaces ofthe saine pair, of parallel longitudinal line-elements, each action-face or driving face of the wheel, say f", has a rearward skew, the extent of which. is indicated by the angle or are cl3. The wheel teeth h intervening between the adjacent tooth-spaces F are tapered inwardly. The tooth-spaces themselves are of 'uniform width or crosssection from end to end, if such cross section be taken in planes perpendicular to the respective master-form axis m. It will be seen that a pair of surfaces, such as 2l and 22, formed of parallel longitudinal elements, is, followed by another pair of surfaces, as 23 and 24;, also composed of parallel longitudinalelements, but the rlongitudinal lineelements of the surfaces 2l, 22 are not parallel to the similar elements of the surfaces 23 Q4, but in a` convergent. relation thereto, as ndicated by the angle Z2. Thus, of any three sucd cessive tooth-surfaces, two have the same master-forni axis and are composed of longitudinal circular-arc elements parallel to said axis, while the third surface has longitudinal line elements parallel to another master-form axis. This relation as regards the working tooth-surfaces of the wheelis true of all forms of my invention shown herein.

In Fig. t I have illustrated what may be termed a skew bevel wheel having working tooth-surfaces arranged in pairs on the toothzone l of the wheel body B, in substantially the same manner as described with reference to Fig. The difference lies in the direction of the tooth-zone secants subtending the master-form axes, indicated at m12, which secants, instead of passing through the axis of the cone (as does the instant axis have a strong Obliquity or skew, as indicated by the angle e6. The axes m12 are circular arcs as before.

The rearward skew indicated at cl3 in Fig. 3, and the similar but greater skew obtained with the arrangement shown in Fig. 4, result in a very gradual meshing of such wheels with their respective pinions, thus securing a very smooth operation.

As stated above, any one of the three kinds of wheels shown, may have its tooth-surfaces formed in pairs, by moving (rotating) in a path corresponding to the position of the corresponding master-form aXes m13, or x12 respectively, a tool, such as J in Fig. 9, having a profile corresponding to that of the tooth-space F (Fig. 5), the wheel body or blank being held stationary during the motion of the tool. Of course, a relative circumferential movement of the blank and tool (the so-called indeXing) is eifected after one pair of tooth-surfaces has been completed, to bring the tool into working relation to another pair of tooth-surfaces.

YThe pinion P (Figs. l and 7) is formed with teeth g the working tooth-surfaces of which, j2, terminate at the tooth-zone in edges These tooth-surfaces may be formed in pairs by means of a tool, such as T, which is a counterpart of the tool J employed for forming a pair of tooth-surfaces on the wheel. lVhile in the case of the wheel, theproiile of the tool I is shown as corresponding to that of a tooth-space F, so that said tool may produce at the same time two tooth-surfaces located at the saine tooth-space, the correspond ing pinion-cutting tool T has aprofile correspending to that of thecross 'section of" a pinion-tooth g, so that said tool may produce at the same time two tooth-surfaces on the same tooth. The operation mi ghtV be reversed, that is, the tool kT might be Iemployed to cut a pair of tooth-surfaces f3, 'f5 on the same tooth ofthe wheel B, as'inidicated yin Fig. 6, in which i 'case ther'counterpart tools J would be employed iforf" producing i onl the pinionP, pairsoftooth-su`rfaces, eachpair being at theasame tooth-space.` `lNhether` the tool J or the tool T isemployedin conjunction with the wheel B, theinotion of such tool` `would be in a curvilinear path, and preferably in the arc of a circle, as referred to above..` In cuttinguthe pinion tooth-surfaces, the pinion blank and the tool would be given a relative `movement such as'the toothfsurfaces of the wheelhave relatively `to those ofthe` pinion whenthese two gears are operating in mesh with one another, the pinion-.cutting tool corresponding to the toothsurfaces of the Wheel, or rather to a pair of consecutive.tootlnsurfaces of the wheel.` In

addition to this relative rolling movement of` the tool and pinion blank, the tool would be given a longitudinal cutting movement in a curved path, and specifically in a circular arc, so that at one cutting movement'or cutrtingstrolre of the tool, two points ofsaidtool will cut longitudinalparallel lines such as i e', e" `on the two tooth-surfaces of the same pair, said lines being arcs ofcircles" corresponding to the path of the tool. Of-course,

owing to the relative rolling motion just re` ferredto, the pairof parallel lines cut at the next stroke of the tool will not be, parallel (on the surfaces y?) to the pair e', e" first mentioned; still,the twosurfaces jg of the same pair will be composed of` longitudinal line elements in the natureoflcircular arcs, each line element of one surfacehavinga corresponding` lineelement, parallel to it, on the `other surface of the pair. From the inode of production described itfollows that while the two tooth-surfaces of the same pair on the wheel` will have `an untwisted form or construction, owing to their singlewreproduction configuration, the mating pair of conju-V gate pinion tooth-surfaces, owing to their peculiar compoundreproduction.L configuration,..v.vill have a` twist throughout their lenothm 1p p. t i

Iii the diagram Fig. V8, w3 vindi-catesthe axis ofytlie wheel-blank Buma andmir are circles` of equal radii, having their centers on saidV axis at c and o respectively, and each lying in a plane of rotation, that is to say, these two circles lie in parallel planes perpendicular to the axis w3; the.circle/m,3 may be saidto be described by the endof the ,radius m2 rotating about saidaxis, and this circle indicates the geometric pitch-surface corresponding tothe pitch-circle 7 indicated in Figs. l and 2. The outer end of the radius m2 is designated as tra?, andlies in the instant axis. At c', g/ I have indicated a radius parallel to m2, the` `point y `lying on the circle m4. With the pointy as acenter, "andvjwc as a radius, I have drawn a circle m5, having a radius 3b perpendicular to y, c. This circle may be described as the orbital path of the point a (at the outer end of the. radius 3b) around the point y.

L The vertex ma and the points y, a lie in a plane `right-angledtriangle the plane of which is tangential to the geometric pitch surface, said sur `acebeingthe geometric surfaceiof revolution generated by the line m (connecting @am with y) revolving about the wheel-axis ma. This triangle ma", y, a has its hypotenuse m13 (wai-5) curved according tothe arc of a circle and forming the master-form axisof the pairoftooth-surfaces cut on the wheel by a motioniof the tool in apatli corresponding to said `master-form axis ,in this case, the tooth-Zoneof the wheel (as l in Fig.` 2) being 1 located contiguous to the meridian `circle m3 of Fig. 8, the geanwheel will be of theparticular kind which I designate as a skew-spurl. i In Fig. 8 the position m12 of the master-form axis (Figs. et) is indicated by al dotted` curved line, representing 'aniother position ofthe hypotenuse line, and when this location of the ,master-forni axis is employed, a\slewbevel wheel having teeth of the character shown in Fig. 4 will result. Thus the inaster-form axis coincides ineach case with a `plane-triangle hypotenuse line,

, which (in some part of its length) touches the tliecurvilinear forms of the tooth-surfaces having longitudinally-parallel elements, and to the rectilinear forms disclosed more fully in my pending application above referred to, my present" application is specific' to those formsin which themaster-form axis is curvi! linear. `z

It will beunderstood that as thetool J or T performs its cutting action, it is also given the usual feeding movement toward the blank so that it may cut into the blank more deeply atfsuccessiveworling movements or cutting strokes.

. Iclaim as my invention;

. `l. A gear wheelhaving teeth with working surfaces of single-reproduction configuration, saidsurfaces being arranged in pairs of adjacent surfaces, the two surfaces of the same pair having curved-line elements parallel to a` curved master-form axis located be-` tween the surfacesof such pair. i

1` 2. A gear `wheel having teeth with working-surfaces of singleereproduction` congurations, said surfaces being arranged in pairs of adjacentsurfaces, the two surfaces of the same pair having line-elements of circular curvatureparallel to a master-form axis of circular curvature located between the surfaces of such pair.

3. A pinion having teeth with Workingsurfaces of compound-reproduction configuration conjugate to tooth-,surfaces of single-reproduction configuration containing Vparallel curved-line elements extending lengthwise of the last-named tooth-surfaces.

4. A pinion havin teeth with workingsurfaces of compoun -reproduction configuration conjugate to tooth surfaces of singlereproduction configuration containing parallel' longitudinal line elements of circular curvature.

5. A pair of toothed gears adapted to mesh, one of said gears having teeth with workingsurfaces of single-reproduction configuration containing parallel longitudinal curvedline elements, and the mating gear having teeth with working-surfaces of compoundreproduction configuration conjugate to the said tooth-surfaces of single-reproduction configuration.

6. A pair of toothed gears adapted to mesh, one of said gears having teeth with workingsurfaces of single-reproduction configuration containing parallel longitudinal line elements of circular curvature, and the mating gear havin teeth with working-surfaces of cornpoun -reproduction configuration conjugate to said tooth-surfaces of single-reproduction configuration.

7. The herein described improvement in toothed gearing, it consisting in a pair of gears comprising a master-wheel provided with teeth each having a working-surface with uniform profiles throughout the length thereof and each surface having surface elements parallel with a geometric master-form axis which coincides with the curvilinear hypotenuse of a curved sided plane-triangle another side of which, at a plurality of points in the length thereof, coincides with a lineV lying in a geometric plane passing through the wheel axis, the vertex of said triangle being in the instant axis of said gears, and said wheel tooth working surfaces conforming to the single-reproduction configuration,

in combination with a mating pinion having wheel-engaging teeth each provided. with a working surface conjugate to said wheeltooth Working surfaces and conforming to the compound-reproduction configuration.

8. A bevel gear wheel having curved teeth with working surfaces of single reproduction configuration, said surfaces being arranged in pairs of adjacent surfaces, the two surfaces of the same pair havingl curved line longitudinal elements parallel to a curved master-form axis located between such surfaces.

9. A bevel pinion having curved teeth withV working-surfaces of compound-reproduction configuration conjugate to tooth-surfaces of single-reproduction configuration containing parallel curved-line longitudinal elements.

10. A bevel pinion having curved teeth with working-surfaces of compound-reproduction configuration conjugate to toothsurfaces of single-reproduction configuration containing parallel longitudinal elements of circular curvature.

ll. A pair of bevel gears adapted to mesh, one of said gears having curved teeth with working-surfaces of single-reproduction configuration containing parallel longitudinal curved-line elements, and the mating gear having curved teeth with working-surfaces of compound-reproduction configuration conjugate to the tooth-surfaces of single-reproduction configuration.

12. A bevel pinion having teeth with working surfaces of compound-reproduction configuration, said surfaces being arranged in pairs of adjacent surfaces, the two surfaces of the same pair being conjugate to tooth surfaces containing parallel curved-line longitudinal elements.

13. A gear having teeth fashioned with faces conforming to arcuate surfaces of different radius respectively, said surfaces generated from a common center.

14. A geared couple consisting of a gear having curved transverse grooves in its tooth-bearing part spaced equally about the axis of the gear, the opposite faces of each individual groove being curved about the same center, and the centers of curvature of the several grooves being all diHerent and a complemental gear having a series of teeth similarly spaced, the opposite faces of each tooth havinnf the same curvature as the complemental faces of the grooves in the first gear. f

15. A gear constituting one member of a geared couple having curved teeth and intermediate tooth spaces, the opposite faces of any one tooth being curved about the same generating center with different radii of curvature, and the faces yof ldifferent teeth being curved about different generating centers.

16. A gear having teeth with working surfaces of compound reproduction configuration, said surfaces being arranged in pairs corresponding to arcuate surfaces of different radius respectively, said surfaces generated from a kcommon center.

17. A gear having teeth fashioned with Working surfaces of compound reproduction configuration, said surfaces conforming to arcuate surfaces of different radius respectively.

I HARVEY D. WILLIAMS.

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