US2401446A - Method of grinding clutches, gears, and other toothed parts - Google Patents

Description

June 4, 1946. V E. WILDIHABER 2,401,445

v METHOD OF GRINDING GLUTCHES, GEARS, AND OTHER TOOTHEDPARTS Filed March 31, 1944 2 SheetS-Sheet 1 I Smaentor 8B fi zmas'r ,WILDHABHL I homeg- June 4, 1946. E. WILDHABER 2,401,446

METHOD OF GRINDING CLUTCHES, GEARS, AND OTHER TOOTHED PARTS Filed March 31, 1944 tlzm'fisT Wu LDHABEIZ attorney 2 Sheets-Sheet 2 Patented June 4, 1946' 2,401,446 METHOD OF GRINDING CLUTCHES, GEARS,

AND OTHER TOOTHED PARTS Ernest Wildhaber, Brighton, Gleason Works, Rochester,

of New York N. Y., assignor to N. Y.,.a corporation Application March 31, 1944, Serial No. 528,885

The present invention relates to the grinding 11 Claims. (Cl. 51-287) of the tooth surfaces of face clutches; spiral bevel and hypoid gears, and of other toothed members, especially where the grinding surface and the surface to be ground are counterparts of one another, as is the case in certain types of face clutches, and non-generated spiral bevel and hypoid gears.

In the grinding of face clutches, it is the usual practice to grind both the sides and the bottoms of the tooth spaces. Ordinarily, a rotary annular grinding wheel is employed, and grinding is effected by rotating the wheel in engagement with the work while producing a relative feed movement between the wheel and work in the direction of the wheel axis. In such an operation, the rate of feed of the wheel is determined by the rate at which stock can be removed from the bottom of a tooth space, and the relative rates of feed in directions normal to the tip and sides of the wheel will, therefore, obviously be unequal, because the tip and sides of the wheel are diiferently inclined to the axis of the wheel. This causes unequal wear on the tip and sides of the wheel. Moreover, when the tooth spaces of the work have been previously cut, and the grinding operation is used only to remove very slight amounts of stock from the sides and bottoms of the tooth spaces, the wheel will contact the side of a tooth space long before it contacts the bottom of the tooth space, and, while the wheel may be fed into the work at a. relatively fast rate while it is grinding only a side of a tooth surface, the feed has to be slowed down prior to engaging the tooth space bottom. Sometimes the rate of feed in a direction normal to the tooth side is then so reduced that danger of burning the tooth side arises through rubbing of the side of the wheel against the side of the tooth. These difliculties have all seriously hindered the development of clutch-grinding.

In grinding non-generated spiral bevel and hypoid gears, the usual practice is to grind both sides of a tooth space simultaneously, and frequently the bottom of the tooth space is also ground in the same operation with the sides.

Here the difilculties arising from the differences in relative rates of feed on the sides and tip of the wheel have been recently aggravated by the fact that it has lately become the practice to grind nonenerated spiral bevel and hypoid gears with wheels whose opposite sides have unequal pressure angles so as to obtain more favorable tooth shapes on the teeth of the mating pinion. The unequal pressure angles on the two sides of the wheel mean that the relative rates of feed of the wheel are not only different between the tip and each side of the Wheel but between the two sides of the wheel themselves.

.A primary object of the present invention is to provide a method for grinding clutches, gears and other members having formed tooth surfaces in which the rate of feed may be equalized on the sides and tip of the grinding wheel.

. A further object of the invention is to provide a method for grinding parts, such as mentioned, in which, because of equalization of the rates of feed and equalization of wheel-wear on the sides and tip of the wheel, the tooth surfaces may be round at a faster rate than heretofore without danger of burning.

Other objects of the invention will be apparent hereinafter from the specification and, from the recital of the appended claims.

In grinding a clutch or gear or other part according to the present invention, the wheel i fed relative to the work in a direction normal to the two sides of the work which are engaged by the wheel. In the case of clutches, this means that the feed employed is in a direction bisecting the angle between the side and the bottom of the tooth space being ground, and in the case of non-generated gears, whose opposite tooth sides are to be ground simultaneously, this means that the feed will be in a direction bisecting the angle between the two sides of the tooth space. There are two outstanding advantages obtained with the present invention. The'two sides, or the side and bottom, of a tooth space may be engaged by the grinding wheel simultaneously, and the feed on the sides, or on the side and bottom, is balanced and can therefore be kept at a maximum on both sides or on both the side and bottom. Therefore, the feed motion is not limited, as in the past, by the maximum rate of feed possible on one side or on the tooth space bottom, but can proceed at top speed on both engaged surfaces, simultaneously.

Several difierent embodiments of the invention are illustrated in the accompanying drawings, in which:

Fig. 1 is a sectional view in a plane perpendicular to the axis, illustrating diagrammatically the 7 method of grinding a clutch member according to the present invention;

Fig. 2 is a fragmentary side elevation showing two face clutch members made according to this invention in engagement;

Fig. 3 is a part elevational, part sectional view along the line 3-3 of Fig, 1, further illustrating the principles of the invention as applied to the: grinding of a. face clutch member, which has side tooth surfaces of positive pressure angle;

Fig. 4 is a fragmentary sectional view illustrating one method of grinding according to this invention a face clutch member having side tooth surfaces of zero pressure angle;

Fig. 5 is a similar view illustrating one method of grinding the clutch member which is to mate with the clutch member of Fig. 4;

Figs. 6 and 7 are a fragmentary plan view and a fragmentary sectional view on the line 1-1 of Fig: 6. respectively, illustrating one method of grinding non-generated spiral bevel or hypoid gears according to this invention; and

Fig. 8 is a fragmentary plan view, illustrating diagrammatically the structure of a grinding machine which may be employed to practice the invention.

Fig. 2 shows a pair of mating clutch members l0 and II in engagement. The two clutch members may be of identical construction, or one may have longitudinally convex tooth sides and the other longitudinally concave tooth sides as described in my copending application Serial No.

444,031, filed May 22, 1942, and which matured as Patent NO. 2,384,582, dated September 11, 1945.

or inclination to the axis I! of the clutch."

The present invention is herein specifically illustrated as applied to the production of the clutch member "I whose opposite side tooth surfaces are of longitudinally convex shape, but it will be understood that the invention is equally applicable to the production of a clutch member whose opposite tooth surfaces are both longitudinally concave, or one longitudinally convex and the other longitudinally concave. In fact, the invention may be applied to the grinding of the tooth, surfaces of a clutch member regardless of its lengthwise tooth shape.

- The clutch member 10 shown is made accordin to the principles of my prior application Serial No. 444,031 above mentioned and has the opp site sides of spaced teeth formed as parts of a common surface of revolution. In the illustrated embodiment, they are parts of a common conical surface. Thus, the side ISa of a tooth In of the clutch member is a part of the same conical surface which contains the opposite side llb of a spaced tooth i2b of the clutch member. This conical surface is denoted in Fig. 1 by the line It. Its axis is at I] parallel to the axis ll of the clutch member.

The two tooth sides "a and llb and all other pairs of tooth sides can be ground simultaneously with the inside conical surface I! of a rotary annular grinding wheel 20 whose inside surface'is of the same pressure angle as the side tooth surfaces l3 and I4 and whose axis 2| in full depth position coincides with theaxis I'l of the tooth surfaces. The inside surface of the grinding wheel, in other words, is the counterpart of the side surfaces to be ground.

' is withdrawn from engagement with the work, and

the work is indexed. With such feed. the inside surface I! of the wheel contacts the tooth si es grinding stock is left previously stated,

Each member has teeth I! whose opposite side surfaces l3 and H are of positive pressure angle 4 i3 and ll of the tooth spaces long before the tip surface 22 of the wheel contacts the tooth space bottom l8, assuming that the same amount of I on the sides and bottoms of the tooth spaces which is the usual practice. with the previous method of grinding, then, the axial feed movement of the wheel may be at a relat vely fast rate during the grinding of the sides of the teeth but has to be slowed down for the grinding of the tooth-space bottoms. It is this reduction in feed rate that in some cases, as

, .causes the feed movement normal to the sides of the tooth spaces to become so small that danger of burning the sides arises through rubbing.

tion, in'at least the final stage of grinding, when the sides and bottoms of the tooth spaces are engaged bythe sidesand tip of the wheel, the feed movement is in a direction bisecting the engaged tooth surfaces. The grinding wheel may, however, during the first part of the reed movement. beadvanced at a relatively rapid rate along its axis 2| from a position such as denoted in dotted lines at 20 Fig. 3, where the wheel is disen aged from the work, to a position such as'denoted at 20", where it has entered into two spaced tooth spaces of the work but where it is still out of grindingengagement with both the sides and the bottoms of the tooth spaces. The axial feed movement in fact is preferably continued to a point where the separation between the wheel sur- Heretofore a clutch of the character shown has only in its final stage II, has, of course,

' space. In other words,

all of the tooth sides have face and the work is at a practical minimum, and sometimes in the final stages of this axial feed movement, the active side surface of the wheel will then actually come into grinding engagement with the high teeth of the work. When this position is reached, the direction of the feed movement is changed in the method of the present invention, and the wheel is then fed, as already described, in a direction 2! which is inclined to the wheel axis 2| and which approximately bisects the angle between the side surface of a tooth space being ground and the bottom of thattooth in the final stage of the feed movement, the wheel is fed from position 20" to the full line position 20.

Mathematically, the side profiles of the tooth surfaces being conical would appear as curved lines in the section of Fig.3. They are, however, herein shown straight for the purposes of illustration. The shown straight lines can be considered as the mean tangents to the tooth surfaces.

In practicing the present invention, one pair ground for their same limited depth, the wheel may be fed fur-- ther into the work and a second grind at a further limited depth taken on all the teeth, and this operation may be continued until the wheel has been fed in direction II into full depth and depth. In either method, the feed erably in the direction of the wheel axis and in a direction inclined thereto and bisecting the angle between the side and the bottom surfaces to be ground.

An'annular grinding wheel, such as the wheel surface contact with the work. To avoid burning of the work surfaces, it may be desirable to impart a series of rapid reciprocabeen ground to full is first pl6fneonate tions to the wheel during the grinding operation according to the principles of the method disclosed in Ccndon Patent No. 1,979,876 of November 6, 1984;. With this method, the feed from the position Bil" to the full line position is in the direction of the arrow 25 is performed in an oscillatory manner, in other words, it is broken up into a series-oi miniature strokes whereby grinding engagement time. This permits of maintaining a suitably fast grinding speed during actual grinding contact even on a clutch member of large face width where continuous contact between the wheel and the work would be too much for the wheel to handle and wheres. mere reduction in the rate of feed might cause burning.

Fig. 4 illustrates the a plication of the procceases part of the;

ess to the grinding of the sides and bottoms of v the tooth spaces of a clutch member liil whose tooth sides 88 and shore of zero pressure angle, that is, extend in the direction of the axis 35 of the clutch member. Here an annular grinding wheel all? may be employed that has an inside active grinding surface 3Q which is. of. positive pressure angle and inclined to the axis til of the wheel, and that has a tip surface 32 which is conical and inclined to the inside or" the wheel at such an angle as to produce tooth space bottoms in the worlr which are perpendicular to the tooth sides ill and 32 of the work. The wheel as is positioned in engagement with the work so that the axis 655 oi. the wheel is inclined to the root surface oi the work at substantially the pressure angle of the active side surface oi the wheel. Here, as in the previously described embodiment oi the invention, the gnndiug wheel is first advanced axially and then the direction oi feed is changed to follow the arrow 65 which bisects the angle between the side 35 or of a tooth space and tom 33 of that tooth space. tion of the wheel is shown in dotted lines at 38 in the final position or its axial feed movement and in full lines at ts in the final position of its inclined feed movement. Again opposite sides of spaced teeth oi the work may be ground simultaneously to have longitudinally convex side surfaces which are parts of a common conical surface of revolution.

The tooth spaces of the clutch member so, which is to engage with clutch member Bil, may

The active porbe ground with the outside conical surface so of a rotary grinding wheel 6b whose axis $8 is in cllned to the root surface 53 of'the work at substantially the pressure angle of the active side surface of the wheel. As before, the wheel may be advanced axially until it approaches grinding contact, and then the direction of feed is changed to follow the bisector 65 of the angle between a tooth side st or 52 oi the work and the tooth-space bottom til.

The invention is by no means limited to production of clutch members. Figs. 6 and '7 show how the principles of this invention maybe applied to the production of spiral bevel and hypoid gears with grinding wheels whose opposite sides have different pressure angles.

it denotes the gear which is to be ground. This gear has opposite side tooth surfaces ll and i2 and rounded tooth space bottom surfaces 12. For grinding the gear, a rotary annular grinding wheel til is employed whose inside. outside, and tip surfaces Si, 82, and 83, respectively, are counterparts of the profiles of the side and bottom surfaces ll, 72, and 13, respecthe bot- 6 tively, oi the tooth spaces of the gear, but,

whereas the side surfaces H and 12 of the gear are of equal pressureangle or inclination to the gear axis 15, the inside surface 8| of the wheel is of substantially greater pressure angle than the outside surface $2 of the wheel, being more inclined to the wheel axis 85.

When a wheel, such as the wheel 80, having un-' wheel into the work is in a. direction inclined to the wheel axis 85 and along a, line 83 which substantially bisects the angle between the two sides i: and E2 of the-tooth space being {ground Two different positions of the wheel duringifeed are shown in full lines at 8% and in dotted lines at so, respectively. direction 86 until full depth position has been reached and the tooth space" has been -fully ground. Then the wheel is withdrawn from engagement with the work and thework indexed tobring the wheel into position togrind a new tooth space. As before, the wheel may be oscillated back and forth during the feed movement to avoid burning according to the principles of the Camden patent above mentioned. The two sides of the tooth space are surfaces of revolution.

Fig. 6 represents a view along the axis 35 of the sides of a tooth space of a gear. 88 is the gear apex and 7% denotes the gear axis projected into the plane of the drawing. 88 and flit, respectively, denote the paths of points in opposite sides of the wheel during the grinding of opposite sides 76 and it of a tooth space of the work.

The invention may be practiced on any suitable type of grinding machine. Fig. 8 is a frag mentary plan view illustrating diagrammatically the structure of one such machine. is again clenotes the gear to be ground, is its axis, and it its apex. The grinding wheel 80 is secured to a spindle (not shown) which may be driven by a motor or any other suitable means. The spindle may be journaled in a sleeve (not shown) which is movable in the direction of the axis 55 of the wheel to produce the axial feel movement of the wheel. This movement may be efiected in known manner by a rotary cam. The sleeve is mounted on a slide 9b which is adjustable along the wheel axis so to permit of compensation for wear of the wheel. The slide is mounted on a swivel plate which is pivoted at 92 on a Slid ing base 93, aguide way so being provided on the upper face of the sliding base 93 for this purpose, The pivotal adjustment of the plate @l permits or adjusting the axis of the grinding wheel at any 'desiredangle to the. direction 98 of mo-- tioncf the sliding base to on the bed 97 of the machine. Motion of the sliding base Q3 may be controlled by'a cam or any other suitable means. The work-piece F8 is mounted in a 'worlrheacl which is adjustable on the angularly about'the apex le er the work, la er ally. axially, and" vertically, that is, parallel to the pivot axis l6. I i

In operation, the wheel is first moved axially by the cam on the sleeve to near grinding position and then is fed, by movement of the sliding base Thewheel reed continues-in theground as coaxial conical.

bed of the machine tion about the work axis.

93, in the direction 86 which bisects thesides of the tooth space being ground. The latter feed may be continuous or be a reciprocatory feed movement of the general type described in the Condon patent. Usually a plurality of cycles are performed in each tooth space of the work, the wheel being fed a limited distance during each cycle and then being withdrawn and the work indexed, the feed being preferably an intermittent feed movement taking place after a cycle of operation has been performed on each tooth space of the work. v

The machine described with reference to Fig. 8 may be used for grinding clutches as well as gears. When a clutch is to be ground, the work is so set up that the direction 25 (Fig. 3), ll (Fig. 4) or I! (Fig. 5) of grinding feed proper coincides with the direction 98 of feed of the sliding base 93.

The invention can also be practiced, both in the grinding of non-generated gears and of clutches, on Gleason spiral bevel and hypoid generators of known construction which are provided with means for tilting the grinding wheel. this case, a feed movement in a direction inclined to the wheel axis may be performed in the normal plane, such as the plane I! of Fig. 6 which contains the wheel axis It. Further than this, the feed in the direction inclined to the wheel axis may also be attained as the resultant of a plurality of feed motions. for instance, as a combination of feed along the wheel axis and feed angularly about the work axis. In other words, the grinding feed proper may consist of a feed alon the wheel axis plus a simultaneous rotary mo- While the invention has been described in connection with the grinding of gears and clutches with an annular type of grinding wheel, it will be understood that it is also applicable where a cupped wheel is employed. It will further be understood that the invention is not limited to the production of clutches and of non-generated gears, but may be employed also in the production of other parts where there are two surfaces to be ground which are inclined at an angle to one another. It may thus be used, for instance, in the sharpening of blades of a milling cutter where the front face of a blade and the bottom of the space between successive blades have to be ground simultaneously. Again, the feed is in a direction bisecting the surfaces which are to be ground. In all cases, the surfaces ground are surfaces of revolution; such as conical or spherical surfaces, or planes; and ordinarily surface contact between the wheel and the work exists at least for an instant. In general it may be said that while certain embodiments of the invention have been illustrated. the invention is capable of further modification and this application is intended to cover any variations, uses,'or adaptations of the invention following, in general, the principles of the invention andincluding such departures from the present disclosure as come within known or customary practice in the art to. which the invention pertains and as may be applied to the essential features hereinbei'ore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

l. A method of simultaneously grinding a side and the bottom of a tooth space of a toothed member, which comprises employing arotary grinding wheel that has a side and a tip surface which are counterparts, in shape and in inclination to one another, of the side and bottom of the tooth space to be ground, and rotating the wheel in engagement with the work while effecting a relative depthwise feed movement between the wheel'and work in a direction other than at right angles to the wheel axis and approximately bisecting the angle between the side and bottom of the tooth space.

2. A method of simultaneously grinding a side and the bottom of a tooth space of a toothed member, which comprises employing a rotary grinding wheel that has a side and a tip surface that are counterparts, in shape and in inclination to one another, of the side and bottom of the tooth space to be ground, and rotating the wheel on its axis whil effecting a relative depthwise feed movement between the wheel and the work in a direction substantially normal to the bottom of the tooth space until the wheel and work are approximately in grinding contact, and then effecting a relative depthwise feed movement between the wheel and the work in a direction other than at right angles to the wheel axis and approximately bisecting the angle between the side and bottom of the tooth space until full depth position is reached.

3. A method of grinding simultaneously opposite sides and the bottoms of two spaced tooth spaces of a face clutch member which has side tooth surfaces of positive pressure angle, which comprises employing a rotary annular grinding wheel that has sid and tip surfaces which are counterparts, in shape and inclination to one another, of the sides and bottoms of the tooth spaces, positioning said wheel with its axis parallel to the axis of the work and so operate in two spaced tooth zones of the work simultaneously, and rotating the wheel in engagement with the work while effecting a relative depthwise feed movement between the wheel and work in a direction inclined to both the axis of the wheel and the axis of the work and bisectlns the angle between a side and the bottom of a tooth space.

4. A method of simultaneously grinding a side and the bottom of a. tooth space of a toothed member which comprises employing a rotary annular grinding wheel that has a side and tip surface which are counterparts, in shape and inclination to one another, of the side and bottom of the tooth space, and rotating the wheel on its axis while effecting a relative feed movement axially of the wheel until the wheel and work are approximately in grinding contact. and then effecting a relative feed movement in a direction inclined to the wheel axis and approximately bisecting the angle between the side and bottom of the tooth space until full depth is reached.

5. A method of simultaneously grinding opposite sides of a tooth space of a toothed member whose opposite side tooth surfaces have different pressure angles, which comprises employing a rotary annular grinding wheel which has opposite side surfaces that are counterparts. in shape and inclination to one another, of the sides of the tooth space to be ground, and rotating the wheel in engagement with the work while effecting a relative depthwise feed movement between the wheel and work in a direction inclined to the axes of the wheel and the work and bisecting the angle between the sides of the tooth space.

6. A method of simultaneously grinding opposite sides of a tooth space of a toothed member whose opposite side tooth surfaces have different pressure angles, which comprises employing that it will a rotary annular grinding wheel which has opposite side surfaces that are counterparts, in shape and inclination to one another, of the sides of the tooth space to be ground, and rotatin; the wheel on its axis while effecting a relative depthwise feed movement between the wheel and the work in the direction of the axis of the wheel until the wheel and work are approximately in grinding engagement, and then effecting a relative depthwise feed movement between the wheel and work in a direction approximately bisecting the angle between the sides of the tooth-space.

7. A method of simultaneously grinding on a toothed member two surfaces of a tooth space which are concentric surfaces of revolution and inclined to one another, which comprises rotating an annular grinding wheel on its axis while effecting a relative depthwise feed movement between the wheel and work axially of the wheel and thereafter effecting a relative depthwise feed movement between the wheel and work in a direction at. an angle to the wheel axis.

8. A method of simultaneously grinding two surfaces of a tooth space which are inclined to one another, which comprises rotating a grinding wheel, which has active grinding surfaces that are counterparts of the surfaces to be ground, on its axis while effecting a relative depthwise feed movement between the wheel and work which is in one direction and at a relatively fast rate until the wheel and work are approximately in grinding contact and which is in a direction inclined thereto and at a relatively slower rate until full depth position is reached.

9. A method of simultaneously grinding two surfaces of a tooth space which are inclined to one another which comprises rotating a grinding wheel on its axis while effecting a relative depthwise feed movement between the wheel and angle to the first described feed movement and substantially bisecting the angle between the two surfaces which are to be ground.

10. A method of grinding simultaneously opposite sides of a tooth space of a toothed member whose opposite side tooth surfaces have equal pressure angles or inclination to the axis of said member which comprises employing a rotary grinding wheel that has active side tooth surfaces at opposite sides of unequal inclination to its axis and that in shape and inclination to one another are counter parts of the side tooth surfaces to beground, and rotating the wheel in engagement with the work while eifecting a relative feed movement between the wheel and work in a direction inclined to the wheel axis and blsecting the angle between the opposite sides of the tooth space,

11. A method of grinding simultaneously a side and the bottom of a tooth space of a clutch member whose side tooth surfaces are of zero pressure angle and parallel to the axis of the clutch member which comprises employing a rotary grinding wheel-that has an active side surface of positive pressure angle and inclined to its axis and whose side and tip surfaces, in shape and inclination to one another, are counter parts of the side and bottom of the tooth space to be ground, and rotating the wheel in engagement with the work, while effecting a relative feed movement between the wheel and work in a di-- rection bisecting the angle between the side and bottom of the tooth space to be ground.

ERNEST WILDHABER.

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