US2376109A - Device for rectifying the involute tooth-profile of gear grinding disks - Google Patents

Description

May 15, 1945. A. AEPPLI 2,376,109 DEVICE FOR RECTIFYING THE INVOLUTE TOOTH-PROFILE 0F GEAR GRINDING DISCS Filed Nov. 12. 1945 Patented May 15, 1945 r nnvion' 'ron 'REU'IIFYING THE INVOLUTE or GEAR; cmnnm u i TOOTH-PROFILE T ,DISKS AlberthepplL. zurich, Switzerland, assignor to v Maag-Zahnrader und-Maschinen Aktiengesellscha'ft', Zurich, Switzerland Application November 12, 1943, Serial No. 510328 .In Germany June 11, 1942 ,vcla'im (01. 125-11) a Thi'sinvention relates todevices for rectifying the involuble tooth-profile of gear grinding disks. In devices of this kind hitherto known inwhich the involuble tooth-profile to be formed on the grinding disk is produced. on the principle of relative rolling motion between elements, the

rolling disk must always be displaced laterally from the plane passing through the axis of the grinding disk and the point of the diamond in an amount approximating the radial length of thegrinding disk; for the purpose of giving. free the space required for the rolling. elements to perform their rolling movements. This leadsto an: arrangement in which the diamond. is fastened tothe end of a long armwherebyv the device becomes unstable and the exactness. of the involute form produced is impaired.

The present invention has for its object to arrange the rolling disk directly underneath the grinding disk with a view to dispensing with the arm forsupportingthe diamond turning tool and providing for the-device to become rigid and the involute curve produced to be true to"form-.j

A,-,further object of the presentinvention consists in that with a single rolling arc involute curves for gears with difierent pitch circles can be produced.

A still further object consists in'pro'ducin'g with thedevice; in a simple mannena tooth-outline diverting somewhat from the true involute curve, that is, the tooth-profile of the disk is intended to be given, for example, such a' form that the hitherto often required additional'rounding' off of the taco or the rooth'of the teeth, respectively, can be dispensedwith- The first named object-is carried into effect in thata" carrier is arranged for rocking movement about the axis of a rolling disk on which carrier on one side of said axis of rotation a rectilinear rollinginemberfisguided and is secured to said disk by means'ot rollingstrips, the diamond-being mounted on th'e opposite side on a plungergzthe guide means of which on the carrier extends parallel with the rectilinear rolling member,-and the latter and the plunger of therdiamondturnin'g toolbeingoperatively'connected with each other by means ofja leverage.

The aforesaid second object ;is realised-in that for the plunger of the diamond turning tool a guideway is arranged on a sliding member which is displaceably guidedon the rockablecarrierat is the fact that :in consequenceof. said. displacing movement the ratio of arm lengths of said lever" I right angles to the rolling member. Proof of this age from the axis of rotation of the latter to the point 'of'contact of the rolling member and from said rotation axis'to the point of contact 0:1 the diamond turning tool is varied.- This ratio is however like that existing between the diameter of the rolling disk 'and'that of the pitch circle of thetooth system'to be ground. The diameter of this pitch circle can jthusbe varied while the roll ing disk used can remain unchanged. Final1y,'the third mentioned'object can be'carried out in that one of the "ends of the lever of the leverage is diverted from the rectilinear form by which means a form jof-tooth-profile is obtained' which deviates from the involute curve. I

In the accompanyingdrawing anfold form of rectifying deviceis illustrated together with an exem'plificatiori' ofthe 'sjulojei zt of the present invention inclusive of detail modifications of the latter. v r

"Fig. 1 shows a side elevation of a known rectifying device; I 1 Fig. 2 shows a corresponding front elevation; Fig. 3 shows a front elevation of a preferred form of the present invention; r t :Fig. 4 shows a corresponding side elevation;

Fig. ,5 is a section on the line V--V in Fig 3; v Fig. 6 shows a modified detail of Fig. 3;

Fig, 7 is a section on the line VIIVII in Fig. 6; Fig. 8 is a diagram illustrating differentrelative movements, and

Fig. 9 is a schematic view representing a modified formof the'deviceaccording to the present invention adapted'for'working with screw wheel grinding disks. In the old device a turning mechanism operating on the principle of relative rolling motion between two parts isused' for rectifying the involute tooth-profile of the grinding disk N, the stationary'rolling disk W of which mechanism extends in a plane the distance of which from the middle plane E-E of the grinding disk amounts to the radial length of said disk at'least; On this rolling disk W rolls a rule G which can be connected with the disk W by means of rolling strips. To this rule is connected an arm A which lies transversely to .the latter and carries the diamond turning tool D. Due to the fact that the thrust in the first In the form of this invention shown in Fig. 3 this result has been obtained by securing a supporting structure 20 to the bed of the machine, in which this disk to be rectified by being turned 01f is mounted underneath the profile generating disk N, which structure includes a shaft bearing 2! and a rolling segment 2 coaxially connected with the supporting structure. bearing 2| rests a journal pin l which is rotatable in said bearing and secured to the carrier 3. The carrier 3 is provided with two perforated ears 4 in which a rectilinear rolling member or rule 5 is mounted free from play. This rule is connected wit-h the rolling segment 2 by means of rolling strips 6 and I.

In addition, the carrier 3 is provided With a slideway 9 which extends at right angles .to the rule 5 and on which a slide ,8 is displaceably guided and adapted to be secured in position of adjustment. The slide 8 in turn carries a slide way which extends transversely of its longitudinal direction and serves for the reception of a plunger II. On the latter the diamond turning tool I2 is adjustably fastened. For effecting this fastening on the plunger l l a turntable 22 is arranged relative to which a holder 24- for the diamond I2 can be shifted and can be fixed thereon in position of adjustment by means of a spindle and a knurled button 23.

Further to the carrier 3 a mounting support 14 is screwed which receives an axle pin l3 extending paral1e1 with the pin I. On this axle pin a roller 25 and guide pieces l6 are mounted as well as springs it which maintain a rail IS in bearing engagement with the roller 25 by means of a cross piece. This rail is positioned between the guide pieces IS. The connecting line between the centers I and I3 extends parallel to the rule 5.

The rail l5 forms a two-armed lever with which the plunger ll of the diamond turning tool and the rule 5 are articulated. Such a pivot joint is shown in plan in Fig. 6 on a larger scale. similar to that existing between the carrier 3 and the rail l5 and formed by a roller 25 which is forced into bearing engagement with the rule-- by means of springs l8 and a cross piece H. The

rollers 25 are mounted on the parts I I and 5 respectively, in such manner, that a line extending tangentially to the rolling segment 2 in parallelism to the rule 5 passes through the axis of the roller on the rule 5, and that a straight line extending parallel to said tangent and passing through the diamond turning tool 12 intersects the center of the roller 25 on the slide l I, if the projection represented by Fig. 3 is taken into consideration. As the carrier 3 is pivo-tally displaced relative to'the support the point of the diamond describes an involute curve. It will be seen that the rectifying device described is arranged directly underneath the grinding disk so that the supporting arm A shown in Figs. 1 and 2 is dispensed with. Therefore, the described arrangement provides for guiding the diamond turning tool much more rigidly and precisely.

In Fig. 8 the relative movements of parts are represented. The character do denotes the diameter of the pitch circle for which the in-,

volute curve is to be evolved. D0 refers to the diameter of the rolling segment 2 in Fig. 3 by means of which the involute is to be effected. The character C indicates the fulcrum I3 of the lever l5. The tangent to the root circle of diameter do represents the joining line passing through the point of the diamond l2 and the It is In the point of contact of the lever [5 with the plunger I l The tangent to the rolling circle of diameter Do corresponds to the contacting line of the guide rule 5 passing through the point of contact between the lever l5 and said rule and extends tangentially to the rolling segment 2.

If, with the center assumed to remain in stationary position, the pitch circle do (Fig. 8) is to roll on the straight line a-b this line ab must be displaced relative to the center in the direction of arrow F, on rotation of the pitch circle through an angle a, for a stretch ap equal to an arc length aa'. If ap equals a-a' point p coincides with point a at the end of the rotational displacement for the angular range a.

From Fig. 8 it is evident that on rolling movement for the angular range on the rolling circle of diameter Do a length of rolling equalling the arc length AA' is obtained. If the length AP of the straight line equals A-A' the points A and P coincide on the termination of the rotation movement.

Therefore, as

it follows that on the circle of diameter D0 rolling on the straight line AB the pitch circle of diameter do performs a rolling motion on the straight line a-b. Therefore, it is possible to evolve the involute on a pitch circle of any desired diameter of pitch circle in using the leverage described, as long as the relation C b Do C'-B d0 exists.

With the aid of such rectifying devices toothprofiles diverting from the involute, having, for example, the tooth faces rounded off can be produced in a simple manner, for example, by giving to the lever a form which is diverted from the rectilinear contour, as indicated by a dotted line in Fig. 8.

Such a device can be carried into eficct by varying the construction, for example in a manner as shown in Fig. 6. The lever end portion situated on the side of the rolling segment 2 in Fig. 3 is thus provided with an exchangeable piece I5 which is accordingly curved. By this means the result is obtained that during the end portion of the rolling motion the displacement of the diamond plunger is somewhat increased, so as to become greater than required for producing the true involute form. Consequently the tooth-profile turned onto the disk is bulged outward.

The desired result can, however, be obtained also in that, for example, contacting en agement between the rolling rule 5 and the lever I5 is effected with the aid of a cam which is controlled by a lever arm and comes to bear either on the carrier 3 or the lever l5 when the rolling motion has been carried on to a certain extent. Thereby, a rotating movement is initiated by effect of which the diamond is displaced at variance from the displacement imparted to it through the correct leverage.

In applying the last named procedure, the varying of the ratio ofleverage cannot be effected to any desired extent with the same ease as resulting from the use of a curved lever end portion.

rolling disk, coordinated withthe axis of rolling movement, and acooperative rectilinear 11 n eitectmg the tooth-profiles on the grinding 'diskthe rectifying device is convenientlyclamped in position between the centering points instead 1 of tnus'clampingly holding in place the-sear to ground "By-rocking the carrier- 3 to and fro the ihvoluteis evolved and the disk turned off.

--In pro'ducin'g's'pur as well as screw'gearsalways the involuteappropriate "for the gear end face is carriedinto efiect'for' the reason that the rolling "motion can be cam-red outbnly in the plane of-the rolling disk which extends plan'e'S"(-Flg.9)." I v 1337 means of the device describ ed also such grinding disks can be "rectified which are inparallel to the front tended for grinding screw'gear's. In sO'dOing, apart from=the rolling motionwhich in thisin- I 'stant is efiected by the diamond plunger, the rollmember, means for effecting relative rolling movement between said disk andsaid member "about said axis, a c'arrier coaxially arranged with said diskfor-pivoting-movement about said axisfslide guides ior displaceably' guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a turning-tool carrier plunger disposed on said carrier on the other side ofsaid axis, means for guiding said plungerv parallel with said rolling member, a

-levera'ge including a two-armed lever. operatively. connecting said I member with said plunger, a fulcrum arranged for said lever on said carrier so that the joining line intersecting ing plane-mustbe gradually displaced longitudinallyof a helix in a manner known per se. The turning-oft of the disk must, therefore, be effected feach other-at minute spacings-apart with a view to obtaining the true involute form; ,In connection therewith the pointof the diamond must be adjusted {hire a position substant ally at right angles totheplaile of the grindingdisk, For this,

pur ose, in-"rectifyi'ng devices for screw'wheels the" diamond holder is arranged on the diamond plunger-so that it can be turned relatively thereto and clamped inposition thereon. I

-In -.-th'epreceding' description it is stated that "said fulcrum' and said axis extends parallel with said rolling membergand an articulation between one arm of said lever and said plunger, said leverage arranged to provide a ratio of theoretical lever armlen'gths between said fulcrum'and the pointof rolling contact of said member and thefrolling operation is carried out'by'mean's of a rolling rule through the intermediary'of rolling strips; It is, however.'-a lsofeasible to use a.

toothed sector "cooperating with a racku I v Iclaim: Y 1-. In a device for rectifying involute-tooth profiles on-grindingdisk-S for gear grinding machines,

a roll'irigdisk, coordinated 'with'the ax s of'rollr ing movement, and a cooperative rectilinear rolling member, means foreffecting relative rolling movement between said disk and said member about-swaaxis, a carrier coaxially arranged with said'disk" for pivoting movement about said axis, I slid'eguides for displaceably guiding said rectilinear-selling member arranged on said. carr er on onesidegof said axis, a turning tool carrier plunger disposedon said carrier on the other side "of said-axis;'meansfor guiding said plunger parallel with: said rolling member, and a leverage'opbetween said fulcrum and said articulation equalling the ratio of the diameter of saidrolling disk and saidpitch circle diameter. r 4, a device for rectifying involute-tooth profiles ongrinding disks for gear grinding machines,for grinding workpieces constituted by a gear havinga pitch circle, in combination, a

rolling disk coordinated with the axis of rolling movement, the diameter of said 1 disk being greater than that ofsaid pitch' circle-a -recti "linear rolling membencooperatmg with said disc, means for efie'cting relative rolling movement between said disk and said member about said axis, a carrier coaxially arranged with said disk for pivoting movement aboutlsaid axis,

sli'd guides for displaceablyiguiding said- -rectilinear rolling member arranged on said carrier on one side of said'a'xis, atu'rning tool carrier plunger disposed on said carrier on the other side of said axis, means -forguiding said plunger parallel' with said rolling member, a

I leverageincluding a two-armed lever operatively 'e'rativelyconnecting said; member with said plunger disposed on said. carrier on the other side,

of said axis, means for guidin said plunger parallel with said rolling member, a leverage including a two-armed lever operatively connect ng said member with said plunger, and a fulcrum arranged for said leveron said carrier so that the joining line intersecting said fulcrum and said axis extends parallel with said rolling member.v

3. In a device for rectifying involute-tooth profiles on griding disks for gear grindingmachines, for grinding work pieces constituted by 1 a gear having a pitch circle, in combination, a

connecting saidjfmember with said 1 plunger,- a fulcrum arranged for said lever on said carrier so that the joining line intersecting-said fulcrum 'and 'said axisexten'ds parallelfwith said rolling member, and articulations between said lever arms and said plunger and said 1 member f' ;y leverage arranged to provide "-a'ratio of theoretical lever arm'lengths between said fulcrumand the point of rolling contact of said member and between said plunger articulation equalling, the ratio of the diameter of said rolling disk and said pitch circle diameter.

'5. In a device for rectifying iinvolute-tooth profiles on grinding disks for gear grinding ma:-

chines, for grinding work pieces constituted by a gear having a pitch circle, in combination, a rolling disk coordinated with the axis of rolling movement, the diameter of said disk being greater than that of said pitch circle, a rectilinear, rolling member cooperating with said P disk, means for efiecting relative rolling movement between said disc and said member about said axis, a carrier coaxially arranged with said disc for pivoting movement about said axis, slide guides ior'displaceably guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a turning tool carrier plunger disposed on said carrier on the other side of I said axis, means for guiding said plunger parallel with said rolling member, a s1ide:'carrying said plunger guide means displaceably arranged on said carrier in a direction at right angles to said rectilinear rolling member, a levera'geincluding a two-armed lever operatively connecting said member with said plunger, and a fulcrum arranged for said lever on said carrier so that the joining line intersecting said fulcrum and said axis extends parallel with said rolling member.

6. In a device for rectifying involute-tooth profiles on griding disks for gear grinding machines, for grinding work pieces constituted by.

a gear having a pitch circle, in combination, a rolling disk coordinated with the axis of rolling movement, the diameter of said disc being greater than that of said pitch circle, a rectilinear rolling member cooperating with said disk, means for effecting relative rolling movement between said disk and said member about said axis, a carrier coaxially arranged with said disk for pivoting movement about said axis, slide guides for displaceably guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a turning tool carrier plunger disposed on said carrier on the other side of said axis, means for guiding said plunger parallel with said rolling member, means for altering said parallel movement of said plunger for diverting said tool from its course for producing the correct involute form at certain points of the tooth-profile, a leverage including a twoarmed lever operatively connecting said member with said plunger, and a fulcrum arranged for said lever on said carrier so that the joining line intersecting said fulcrum and said axis extends parallel with said rolling member.

7. In a device for rectifying involute-tooth profiles on grinding disks for gear grinding machines, for grinding work pieces constituted by a gear having a pitch circle, in combination, a rolling disk coordinated with the axis of rolling movement, the diameter of said disk being greater than that of said pitch circle, a rectilinear rolling member cooperating with said disk, means for effecting relative rolling movement between said disk and said member about said axis, a carrier coaxiallyarranged with said disk for pivoting movement about said axis, slide guides for displaceably guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a turning tool carrier plunger disposed on said carrier on the other side of said axis, means for guiding said plunger parallel with said rolling member, a leverage including a two-armed lever operatively connecting said member with said plunger, said lever having an end portion diverting from its rectilinear outline for diverting said tool from its course for producing the correct involute form, and a fulcrum arranged for said lever on said carrier so that the joining line intersecting said fulcrum and said axis extends parallel with said rolling member.

8L In a device for rectifying involute-tooth profiles on grinding disks for gear grinding machines, for grinding work pieces constituted by a gear having a pitch circle, in combination, a rolling disk coordinated with the axis of rolling movement, the diameter of said disk being greater than that of said pitch circle, a rectilinear rolling member cooperating with said disk, means for effecting relative rolling movement between said disk and said member about said axis, a carrier coaxially arranged with said disk-for pivoting movement about said axis, slide guides for displaceably guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a turning tool carrier plunger disposed on said carrier on the other side of said axis, means for guiding said plunger parallel with said rollingmember, a leverage including a two-armed lever operatively connecting said member witn said plunger, a separate piece exchangeably connected to an end portion of said lever and provided with an outline diverting from the rec tilinear outline of said lever for diverting said tool from its course for producing the correct involute form, and a fulcrum arranged for said lever on said carrier so that the joining line intersecting said fulcrum and said axis extends parallel with said rolling member. i

9. In a device for rectifying involute-tooth profiles on grinding disks for gear grinding machines, a rolling disk, coordinatedwith the axis of rolling movement, and a cooperative rectilinear rolling member, means for efiecting relative rolling movement between said disk and said member about said axis, a carrier coaxially ar ranged with said disk for pivoting movement r about said axis, slide guides for displaceably guiding said rectilinear rolling member arranged on said carrier on one side of said axis, a diamond turning tool carrier plunger disposed on said car-- rier'on the other side of said axis, means for guiding said plunger parallel with said rolling member, and a leverage operatively connecting said member with said plunger.

ALBERT AEPPLI.

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