US2660006A - Grinding machine - Google Patents

Description

NOV. 24, 1953 F, HEGEMAN 2,660,006

' GRINDING MACHINE Filed Feb. 25, 1950 4 sheets-sheet 1 H/S ATTORNEY NOV. 24, 1953 HEGEMAN 2,660,006

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 2 HA5 ATTORNEY NOV. 24, 1953 HEGEMAN 2,660,006

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 3 INVENTORJ;

1 H/S Arrow/5x FIG. 6'

Nov. 24, 1953 F. P. HEGEMAN 2,660,005

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 4 uvvawroa; Fm mm 5 Y H/S ATTOENEK Patented Nov. 24, 1953 GRINDING MACHINE Franklyn P. Hegeman, Union, N. J., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application February 25, 1950, Serial No. 146,173

6 Claims.

This invention relates to grinding machines.

An object is to provide an improved machine for grinding the shoulder or flange at the larger end of the tapered raceway on the inner race ring of a tapered roller bearing. Another object is to grind a spherical zone or face on the flange by an apparatus which will avoid chatter and other disadvantages, as by the use of a cupped grinding wheel which partially encloses the work, has an area of contact with the flange, and. is self-dressing. Usually such flanges have been ground conical by a grinding wheel outside of the race ring and having only line contact with the flange. Another object is to provide improved mechanism for supporting and feeding the grinding wheel into the work. To these ends and also to improve generally upon machines of this character, the invention consists in the various matters hereinafter described and claimed.

In the drawings,

Figs. 1A and 1B constitute chiefly a front e evation of the machine with some parts in section.

Fig. 2 is a plan view of the wheel head and a portion of the work head. i

Fig. 3 is a plan view of the work head and a portion of the wheel head, a cam and its mounting being shown out of position in a cut-away portion of the work head.

Fig. 4 is a cross section of a slide and its adjusting means.

Fig. 5 is a left hand end view of the wheel head with the work head supporting plates in section on the line 5-5 of Fig. 1B.

Fig. 6 is a left hand end view of the work head.

Fig. 7 is a diagram.

' Fig. 8 is a right hand end view of the wheel .head with parts omitted.

Fig. 9 is an exploded view of a feed cam and associated parts.

In the diagram, Fig. '7, W indicates an inner race ring having a tapered raceway R and a laterally projecting or outstanding flange F whose inside face S is desirably ground to conform to a spherical surface having its center C in the axis of the bearing. A relief groove is formed where the raceway and flan e would otherwise intersect. The face of the flange between the relief groove and a rounded exterior corner is ground by a cupped grinding wheel G whose axis intersects the point C and lies at an an le to the axis of the race ring. The edge E or front operative grinding face of the wheel is a convex sp rical and sel dressn 'due to it ar of contact with the flange. This area A is narrow but long circumferentially forming a grinding zone indicated by the shaded area and, as the race ring revolves, the whole face of the flange is engaged by the wheel. The long area of contact avoids chatter. The concave spherical face S will conform to the spherical ends of the tapered rollers used in the complete bearing and give them good guidance. No run-in is required.

Referring to assembly Figure 1B, the grinding wheel G is attached'by screws to an adapter 2 secured by a socket-headed clamping screw 4 to the tapered end 6 of a spindle driven by a motor in a head 8 attached by a clam to (Figs. 4 and 8) to a slide"! 2. This slide has dovetail ways l4 guided in ways ona carrier plate I 6 for longitudinal adjustment of the grinding wheel as to compensate for wheel wear. Adjustment is effected by a hand wheel l8 on a shaft 20 journalled in bushings in the carrier plate and having a miter gear 22 meshing with a like gear keyed to a lead screw 24 (Fig. 2) against a collar thereof. V

The lead screw 24 has a smooth portion journalled in a bushing 26 carried by the carrier plate and interposed between a washer 28 and a washer 30. These washers and the bushing are held on the screw shaft by a split nut 32. A nut 34 is attached to the bottom of the slide l2 and engages the lead screw. A floating or second nut 35 is guided in the slide l2 by a tongue in a slot and this second nut is pressed away from the first by a coil spring 38 to avoid backlash. The relative positions of the slide I2 and the carrier plate are indicated by a scale on the hand wheel l8 and by an overlying pointer 40 fastened to the top of'a bracket 42 mounted on the carrier plate. The wheel shaft passes through the bracket.

Feeding movement of the wheel axially to grind is effected by moving the carrier plate IS a short distance while it is supported by parallel reed springs which avoid wear. A reed spring 44 is attached to each end of the carrier plate by a clamping bar 46 secured by socket headed screws. The reed springs are similarly secured to a plate 48 mounted in an angled position (Fig. 2) on a base plate 50. The plate 48 is located on base plate 50 by a pair of posts pressed into the base plate and having rounded heads fitting holes in the plate 48, one of these posts being illustrated at 52.

clamp the plates together. To flex the reed springs and s0 feed the grinding wheel, a lever and cam mechanism is provided. A cam block- Set screws twd'of which are shown at 54 level and support the plate 48 and other screws- 56 is fastened to the bottom of the carrier plate It and is engaged by the circular periphery of a cam 58 having a recess for receiving the hub 60 of an actuating lever 62. The cam has a central hole which is eccentric with respect to its periphery so that, when it is turned around a pivot post 64, it will exert forward thrust on the cam block 55. The pivot post has a bottom flange held down by a flanged clamping disc 86 fastened in a recess to the plate 48. The post has a central recess for a member 68 havin an overhanging flange entering a recess in the hub of the lever. A screw H3 holds the member 68 to the post but the lever and cam are allowed to turn freely as a unit around. the post.

Forward motion of the carrier plate is resisted by a bumper when one of the clamping bars 48 engages the bumper. The bumper comprises a screw I2 adjustably secured in an inner sleeve I4 by nuts threaded on the ends. Rubber like material I6 is bonded to the sleeve and 'to an outer sleeve 18 clamped by a plate 80 in a bumper block 3| which is fastened to the base plate 50. The base plate is rigidly secured to a main frame which may be the frame of a Van Norman oscillating grinder of the type illustrated in the U. .S. patent to Van Norman No. 1,722,691 and whose oscillating column is used only to swine the work head into and out of the grinding position.

The work ring W (Fig. 1A) is clamped in the axis of a suitable chuck a ainst an abutment flange by moving an internally tapered sleeve 82 inwardly along an externally tapered nose 84. The sleeve is slit in from each end to make it expansible against the Work and is engaged by the headed end section '86 of a sectional draw bar 88. The chuck is secured by angularly arranged set screws 90 to an adapter 92 secured to the spindle head by screws, the spindle being suitably journalled in a work head 94 and having a belt driven pulley 96 secured thereon. A coil spring 98 is interposed between the pulley and a collar I III) clamped on the draw bar. A ball thrust bearing I02 engages the collar and a rounded surface I04 on a lever I06 pivoted to a plate I08 fastened on the top of the work head. The lever comprises two companion pairs of angularly related arms rigidly connected by a series of spacing blocks welded between them, the vertical lower end of the lever carrying a cam roller I I which is rotatably secured by a headed stud. The lever is guided between two spaced arms II 2 on a bracket attached to the work head. A coil spring II4 is connected to the lever and to an anchor post on the work head to hold the arm against the thrust bearing. The draw bar spring-98 is the stronger of the two springs and urges the roller IIIl towards a cam II6 which is secured by a screw to a slide II8 which is adjustably' secured on the horizontal leg of an angle bracket I fixed to the main frame. The slide has a tongue entering a groove in the bracket and its adjusted position is secured by a, screw I22. In the working position, the cam roll is remote from the cam but, as will appear, the work head and its mounting can be swung around an axis to facilitate the removal of the work from the chuck which projects into the grinding wheel. Upon this swinging movement around a center point P (Fig. 3) the cam roller engages the cam and releases the work. Fig. 3 shows the cam roller in broken lines against the cam.

The work head 94 is adjustable axially by a screw I24 on an upper slide I26 and that slide is adjustable crosswise by a screw .28 On a lower 4 guide plate I30 which is fastened by screws to a swivel plate I34. The swivel plate is angularly adjustable on a base plate I36 and, for this purpose, a pivot plug I38 having a collar at the bottom extends up through the base plate into an opening in the swivel plate to receive a, securing bolt I40 threaded into the plug with the head of the bolt engaging a washer. A pin holds the washer from rotation and a pin holds the plug from rotation. The swivel plate is locked in angularly adjustable position by a series of three threaded studs I42 which are threaded in the base plate I35 and pass up through three arcuate :slots I44 in the swivel plate to receive clamping nuts and washers. The slots are curved about a center at the pivot plug I38 and this is not the same center as the point P. It will be seen that the swivel plate locates the work spindle axis at a selected angle to the axis of the grinding wheel ber I48 which is secured to the oscillating column of a Van Norman oscillating grinder, of the type illustrated in the U. S. patent to Van Norman No. 1,722,691, and oscillates in that machine around a center at the point P. In that machine this member has a dovetail way I50 for a slide but in the present instance that slideway is not used and the base plate I36 is rigidly secured to the member I48 by screws. In the present machine, instead of constant oscillation, there is only one swinging movement of each work piece. This swinging movement to load and unload the chuck may be accomplished in any suitable way, as by a piston and cylinder unit (not shown) attached to the main frame and having the piston rod engaging a, slot in a disc on the oscillating column. The swinging movement around the center P is limited definitely towards operative position by stop buttons carried in a depending projection I52 on the oscillatable column, the buttons engaging a stop screw I54 in a fixed stop block I56 in one direction and in the other direction by a stop screw I58 in a block I60, both blocks being secured to the frame. The swivelling center of the swivel plate I34, that is, the pivot plug I38 is located in a vertical line at the grinding edge of the grinding wheel and at the relief groove where the tapered raceway R and the spherical face S would otherwise intersect.

The grinding wheel requires a certain thickness for strength but a thick edge would wear near the interior and the exterior portion would ultimately project over the work flange F. To prevent the interference of the wheel with the outer corner of the flange due to such wear, the wheel is occasionally dressed off in an are at its outer edge. For this purpose a diamond I62 is mounted below the lower edge of the wheel for oscillation with a rock shaft I64 having a hand wheel I66. The diamond is mounted on a plug 338 secured by a set screw in a hole in the rock shaft, whose axis lies in a plane including the axis of the pivot plug I38. The rock shaft is journalled near the front end in a roller bearing 110 in a bracket I12 mounted on the base plate I36. The shaft is also journalled in two sets of roller bearings I'M separated by a spacer in a bore at theoverhanging portion of a rear bracket I16. Washers hold the needle rollers in the front bracket and collars hold the needle rollers in the boreof the rear bracket.

In setting up the machine for a particular run of work, a work piece is placed in the chuck and the work head is swung into operative position around the center point P. The intersection of the flange F and the raceway R is then lined up vertically with the center of the pivot plug I38 by proper longitudinal and crosswise adjustment of the two work head slides. The correct radius of the spherical face S is produced by swivelling the swivel plate 1313 around the pivot plug I38 until the work axis intersects the wheel axisat the desired distance from the flange. The swivel plate is then secured by its screws. Before grinding begins, the bumper E6 is under a preload which holds the grinding wheel out of contact with the work. The wheel is advanced into the work by manipulation of the handle to an extent determined by the operator. When the cam handle is swung back, the preloaded bumper moves the wheel away. The work head is then swung around the center pivot P. During this swinging the cam roller H engages the fixed cam H6 and the draw bar is thereby operated to release the work from the chuck.

I claim:

1. In a machine for grinding a spherical surface on a flange upstanding from the tapered raceway of a bearing ring, a work head having a work support journalled about an axis, a cupshaped grinding wheel journalled about an axis intersecting the work support axis, the grinding wheel having a cylindrical wall terminating in a parti-spherical end grinding face to surround the work support and engage the spherical surface of the flange, the center of curvature of said parti-spherical grinding face lying at the intersection of said axes, a swivel plate supporting the work head and having a pivot provided with an axis tangent to said end grinding face, a rock shaft mounted on the swivel plate with its axis in a plane through the pivot axis, and a tool mounted on the rock shaft to cut down the thickness of the outer portion of the wheel beyond the spherical edge.

2. In a machine for grinding a side face on a flange upstanding from the raceway of a bearing ring, a rotatable work head arranged to support the bearing ring, a rotatable wheel head, a grinding wheel mounted on the wheel head and adapted to engage the flange, a carrier plate, a slide mounted on the carrier plate and supporting the wheel head for movement towards the work to compensate for wheel wear, a supporting plate below the carrier plate, parallel springs connecting the plates, a preloaded resiliently yieldable bumper resisting movement of the carrier plate, and a cam mounted on the supporting plate and operatively related to the carrier plate for shifting the carrier plate in opposition to the yieldable bumper.

3. In a machine for grinding a spherical surface on an annular flange outstanding from the tapered raceway of a bearing ring, a work head rotatably driven about an axis and having a chuck arranged to demountably hold the bearing ring, a rotatably driven wheel head journalled about an axis, said axes intersecting in predetermined angular relation, a cup-shaped grinding Wheel on the wheel head and having a' cylin'-' drical wall terminating in a spherical end grinding face engageable with the spherical surface on the flange, the center about which the spherical grinding wheel face is formed lying at the intersection of the axes during grinding, the grinding wheel enclosing a, portion of the chuck during grinding, a swinging support carrying the work head to remove the grinding wheel from said enclosing relation, and cam mechanism operatively connected to release the chuck fromholding relation with the bearing ring, said cam mechanism being responsive to the swinging of the support.

4. In a machine for grinding a spherical surface on a flange laterally projecting from the tapered raceway of a bearing ring, a cup-shaped grinding wheel having a cylindrical wall terminating in an annular spherical grinding face engageable with the spherical surface of the flange, a rotatable work head having a chuck for supporting the ring for rotation, a rotatable wheel head supporting the grinding wheel for rotation, the axis of the work head and the axis of the wheel head intersecting one another on the center of the spherical curvature of the operative grinding wheel face when the grinding wheel is in grinding position, said grinding wheel enclosing a portion of the chuck, a swinging support carrying the work head, a slidable drawbar operatively connected to the chuck, a lever operatively connected to slide the drawbar, an oscillatable member operatively connected to the work head to swing the work head and said swinging support as a unit and carry the chuck out of the grinding wheel, and a cam in the path of the lever causing the chuck to release the bearing ring during the swinging movement of the support.

5. In a machine for grinding a curved surface on a flange upstanding from the tapered raceway of a bearing ring, a support rotatably driven about its axis, a, chuck on the support for demountably receiving the bearing ring, a cupped grinding wheel rotatably driven about its axis and enclosing the end of said chuck, the cupped grinding wheel having a front operative grinding face spherically curved about a center rearwardly of said face and in the axis of said support, the circumferential wall of the grinding wheel being radially thicker than the width of its operative grinding face, dressing mechanism adjacent the forward end of the grinding wheel and engageable with the wheel periphery to cut back said front grinding face to a width approximately equal to the radial width of said upstanding flange.

6. In a machine for grinding a spherical surface on a flange upstanding from the tapered raceway of a bearing ring, a rotatable work head and a rotatable grinding wheel support having their axes intersecting outside of the work head, a chuck on the work head for demountably holding the bearing ring, a cup shaped grinding wheel having an annular end grinding face engageable with said flange, all parts of the end grinding face being equidistant from the intersection of said axes, a pair of slides and a swivel plate supporting the work head, the swivel plate having a pivot provided with an axis, feeding mechanism adjustably positioning one slide axially of the work head, feeding mechanism adjustably positioning the other slide crosswise of the work head, said feeding mechanisms locating the work head with the axis of the pivot tangent ith gm gr nd n face at the rin n Wheel during gr 1: 1-1 2, and adiustable' mechan sm positionia the swiv l p ate i a sel eted location mund the v t e mg rad us. of mg spherical suxfw medu ed: by the rin in Wh e FRANKLYN HEGEMAN.

Referencs Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re 13,892 Van Norman Mar. 1 6 19.1 5 1,401,831 Taylor Dec. 27 1921 1,617,167 Schramm Feb. 8, 1927 1,994,529 Meyer Mar. 19, 1935 Numban 1 Number Q2155. Qmnberg mam-1. J k 2 .32 N nnmg x? "7.1211220- 3 35 Ann 13.. L937. Mar- 11 19.32

walkr Dec. 7, 1943 Carlson 22-2-1922. June 1 1 FOREIGN PATENTS cguntry Dan: Sweden. 2 --r Jan V 6 S p -1 1811 r-.-,- Jan- 2 1938'

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