US3233518A

US3233518A - Method and apparatus for chamfering gear teeth

Info

Publication number: US3233518A
Application number: US328384A
Authority: US
Inventors: Paulger Edward James
Original assignee: National Broach and Machine Co
Current assignee: Nachi Machining Technology Co
Priority date: 1963-12-05
Filing date: 1963-12-05
Publication date: 1966-02-08
Anticipated expiration: 1983-02-08

Description

E. J. PAULGER Feb. 8, 1966 METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH 6 Sheets-Sheet 1 Filed Dec.

INVENTOR.

IOO

E. J. PAULGER Feb. 8, 1966 METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH 6 Sheets-Sheet 2 Filed Dec. 5, 1963 INVENTOR. EDWARD :JAMES PAU'LGER {Z (a J C V 4 ATTO RN 5 E. J. PAULGER 3,233,518

METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH Feb. 8, 1966 6 Sheets-Sheet 5 Filed Dec.

R 2 VI E m w? T 1 R N u, 0 M; w N A 1% A, Q mw C WW D E. J. PAULGER Feb. 8, 1966 METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH 6 Sheets-Sheet 4 Filed Dec.

vmw

INVENTOR.

NON

OON

EDwyD JAMES PAULGER ATTORNE Feb. 8, 1966 E. J. PAULGER 3,233,518

METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH Filed Dec. 5, 1963 e Sheets-Sheet 5 FIG.|6.

FIG.|4.

FIG u '5 INVENTOR EDWARD JAME PAULGER BY WW ATTORNE Feb. 8, 1966 J, PAULGER 3,233,518

METHOD AND APPARATUS FOR CHAMFERING GEAR TEETH Filed Dec. 5, 1965 6 Sheets-Sheet 6 INVENTOR.

EDWARD JAMES PAULGER BY MWW United States Patent ice 3,233,518 METHOD AND APPARATUS FUR CHAMFERING GEAR TEETH Edward James Pauiger, Binley Woods, Coventry, England,

assignor to National Breach & Machine Company,

Detroit, Mich, a corporation of Michigan Filed Dec. 5, 1963, Ser. No. 328,384 9 Claims. (Cl. 90-1.4)

The present invention relates to a method and apparatus for chamfering gear teeth.

Helical gear teeth each have four generally radially extending corners defined by the intersection of the two opposite flanks of the tooth and the two opposite ends thereof. In the case of a spur gear these corners have an included angle of approximately 90 degrees. In the case of helical gears however, two of the corners have included angles which are acute and the remaining two corners have obtuse included angles. In general terms, the acute included angle at the corners of helical gears is equal to 90 degrees minus the helix angle of the gear.

These acute included angled corners are relatively sharp and for several reasons it is desirable to eliminate the acute included angled corner, reducing it to a corner having an included angle of 90 degrees, or in some cases changing it to a corner having an obtuse included angle.

In accordance with the present invention this is accomplished by applying pressure to the flank side of the gear tooth at and adjacent the acute angled corners thereof, thereby displacing metal beyond the adjacent end surface of the tooth and thereafter removing the displaced metal. In accordance with the present invention this is accomplished conveniently by rolling the gear in mesh with toothed chamfering means, the chamfering means including toothed portions generally conjugate to the teeth of the work gear but differing therefrom in lead, maintaining pressure between the work gear and the chamfering means so as to apply pressure as a result of interference between the teeth of the work gear and the chamfering toothed portions with the result that metal is displaced laterally beyond the ends of the teeth and is thereafter removed by a suitable trimming or cutting operation.

It is accordingly an object of the present invention to provide a method and apparatus for chamfering the acute angled corners of the teeth of a helical gear which employs the application of pressure at the flank side of the gear teeth at and adjacent the acute angled corners so as to form a chamfer by the displacement of metal beyond the ends of the gear teeth, and the subsequent removal of the displaced metal.

It is a further object of the present invention to provide a method and apparatus as described in the preceding paragraph in which the pressure is applied progressively along the aforesaid corners of the teeth of the helical work gear.

It is a further object of the present invention to provide a method and apparatus as described in the preceding paragraph in which the progressive application of pressure is repeated a plurality of times to provide a corresponding number of metal displacing operations.

It is a further object of the present invention to provide a method and apparatus as described in the preceding paragraph in which the removal of displaced metal is carried out in repeated steps, and in which the final step of removal of displaced metal removes all of the metal displaced between the ends of the tooth surfaces.

It is a further object of the present invention to provide a method and apparatus as described in the second paragraph above in which removal of metal displaced by the end surfaces of the teeth is carried out to remove all displaced metal therefrom following each metal displacing operation.

3,233,5l8 Patented Feb. s, was

It is a further object of the present invention to provide apparatus for chamfering gears comprising rotary parallel gear and tool supports, means for driving one of the supports in rotation, toothed chamfering means on said tool support comprising chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the helical teeth of the work gear and effective to chamfer the acute angled corners of the teeth of the work gear by the application of pressure thereto, means for establishing a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear, and cutting means engageable with the ends of the teeth of the work gear to remove the metal displaced beyond the ends thereof.

It is a further object of the present invention to provide apparatus as defined in the preceding paragraph in which the means for establishing the pressure contact comprises means for relatively moving said supports.

It is a further object of the present invention to provide apparatus as described in the preceding paragraph in which the application of pressure is the result of relative movement between the supports in a direction radial with respect to the axis of the work support.

It is a further object of the present invention to provide apparatus as described in the foregoing in which the chamfering means includes a guide roll having teeth conjugate to the teeth of the work gear, and in which the means for establishing pressure contact comprises means for effecting a relative feed between said supports in a direction parallel to the axis of rotation of the work support.

It is a further object of the present invention to provide gear chamfering apparatus as described in the preceding paragraph in which the width or axial dimension of the guide roll exceeds the corresponding dimension of the work gear, and in which the means for establishing pressure contact comprises means for relative feeding the supports along a line parallel to the axis of rotation of the work gear, first in one direction and then in the other direction.

It is a further object of the .present invention to pro- Vide a gear chamfering machine as described in the foregoing which includes a rotary cutter engageable with the ends of the teeth of the helical gear to remove the metal displaced beyond the end surfaces thereof by the chamfering operation.

It is a further object of the present invention to provide a gear finishing machine as described in the preceding paragraph in which a pair of rotary cutters are provided at opposite sides of the work gear, and in which the cutters are mounted in fixed position relative to the tool support so that they move respectively forwardly into engagement with the end surfaces of the gear teeth and then away therefrom upon relative movement between said supports in a direction parallel to the axis of rotation of the work support.

It is a further object of the present invention to provide a gear chamfering machine of the character described in which rotary cutters are provided at opposite sides of the work gear and are provided with yieldable mounting means urging them into contact with the end surfaces of the gear teeth so as to remove displaced metal substantially continuously or following each of the repeated applications of chamfering pressure thereto.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is a front elevation of a gear chamtering machine.

FIGURE 2 is a plan elevation of the machine shown in FIGURE 1.

FIGURE 3 is a slightly enlarged side elevation of the machine base with parts in section.

FIGURE 4 is a broken horizontal sectional view on the line d-4, FIGURE 3.

FIGURE 5 is a fragmentary rear elevation of the machine base.

FIGURE 6 is an enlarged side elevational view partly in section, of the work tailstock.

FIGURE 7 is a rear elevation of the tailstock.

FIGURE 8 is a plan view of the tailstock.

FIGURE 9 is a fragmentary side elevation showing the mounting of the tool column.

FIGURE 10 is a plan view of the structure shown in FIGURE 9.

FIGURE 11 is a front elevational view of the structure shown in FIGURE 9.

FIGURE 12 is an enlarged cross-sectional view on the line 12-12, FIGURE 10.

FIGURE 13 is an enlarged section through the tool carriage on the line l3l3, FIGURE 14.

FIGURE 14 is a sectional view on the line 14-14, FIGURE 13.

FIGURE 15 is a fragmentary sectional view on the line i5i, FIGURE 16.

FIGURE 16 is a fragmentary sectional View on the line ra re, FIGURE 15.

FIGURE 17 is a fragmentary edge view of a helical gear illustrating the chamfering operation.

FIGURE 18 is a fragmentary side view of the portion of the gear shown in FIGURE 17.

FIGURE 19 is a diagrammatic view illustrating the chamfering of helical gear teeth by chamfering means consisting of a pair of chamfering rolls.

FIGURE 20 is a diagrammatic view illustrating the chamfering of helical gear teeth by chamfering means comprising a guide roll and a pair of axially spaced chamfering rolls at opposite sides of the guide roll.

FIGURE 21 is a diagrammatic view similar to FIG- URE 20 showing the parts thereof in chamfering position.

FIGURE 22 is a diagrammatic view illustrating the provision of trimming cutters at opposite sides of the work gear.

FIGURE 23 is a view similar to FIGURE 22 illustrating the provision of yieldably mounted trimming cutters at opposite sides of the work gear.

Referring first to FIGURES l7 and 18 there is illustrated a helical work gear It having teeth Ta each of which has end surfaces 14 and 16, top surfaces IE3, and side or flank surfaces 2% and 22;. Considering the tooth as a solid body it will be observed that due to its lead or helix angle, the flank surfaces 25 and 22 form solid included angles with the end surfaces 14 and 16, two of these corners having acute included angles as indicated at 24, and the remaining two corners having obtuse included angles 26.

In gear manufacture it is desirable to eliminate the sharp or acute included angle corners for a variety of reasons. One of the important reasons why this corner is desirably eliminated is its tendency to crumble in use due to the fact that it has an included angle of less than 90 degrees.

In FIGURE 17 at Tb there is illustrated a tooth identical in all respects to the tooth Ta except that the diagonally opposite corner portions 28 and 39 have been chamfered. As illustrated in this figure the chamfered surfaces 2,55 and 30 extend at an angle such that the corner defined by the intersection between the chamfered surfaces 28 and 3t and the end surfaces 14 and to are substantially 90 degrees.

In the past the acute included angle corners of helical gear teeth have been chamfered by operations which include cutting or otherwise machining away material of the teeth directly to produce the chamfered surfaces. In accordance with the present invention, as will subsequently be described in detail, pressure is applied to the acute included angle corners of the helical teeth at the flank side thereof in such a way as to displace metal longitudinally of the teeth or laterally of the gear beyond the end surfaces 14 and 16 of the gear teeth, thus producing the chamfered surfaces 28 and 30. This operation results in the formation of burrs or upstanding ridges of metal extending beyond the end surfaces of the teeth, and the present invention includes the removal of this displaced metal in a particular way.

In general terms, the application of pressure to the flank side of the acute included angle corners is caused to move progressively from crest to root of the gear teeth or vice versa, and this progressive application of pressure is repeated a plurality of times sothat the displacement of metal takes place in a series of steps. The removal of the displaced metal may be accomplished following at least the final few metal displacing operations with the last metal removal step removing all remaining displaced metal which extends beyond the original end surface of the teeth. Alternatively, the metal removal may remove all endwise displaced metal following each successive metal displacing operation. 1

In general terms, the displacement of metal by the application of pressure as aforesaid is accomplished by rolling the gear in mesh with tool structure including toothed chamfering means having tooth surfaces generally conjugate to the teeth of the work gear except for lead, and extending at a lead different from the lead of the helical teeth of the work gear at an angle which determines the direction of the chamfered surface. In the fragment of the gear illustrated in FIGURE 17 it will be observed that the chamfered surfaces 23 and 39 are such as would be formed by spur chamfering tooth surfaces extending at a zero helix angle or having an infinite lead.

It is a characteristic of gear tooth action that the contact between mating teeth moves progressively from crest to root or from root to crest, and accordingly the progressive application of pressure is thus automatically provided in accordance with the present invention. Inasmuch as a continuous application of pressure, or alternatively, a suitable feed movement during continued and repeated rotation of the work gear brings each tooth of the work gear repeatedly into and out of mesh with the chamfering teeth, it will be appreciated that the progressive application of chamfering pressure is repeatedly applied.

Referring now to FIGURE 19 there is diagrammatically illustrated a portion of the helical work gear lti. The teeth portion Ta may be considered as a development into a plane of a circular section taken on the pitch line for example. It willbe observed that the teeth Ta have the acute included angle corners 24 and the obtuse included angle corners 26. chamfering means is provided and is illustrated in this figure as comprising the two

toothed chamfering members

32 and 34 having

chamfering tooth portions

36 and 38 respectively. It will be observed that the

teeth

36 and 38 are spur teeth, extending at a zero helix angle or having an infinite lead. It will further be understood that the chamfering members 32 and 34- are rigidly interconnected and that accordingly, relative angular displacement or rotation therebetween is prevented. It will further be observed that the tooth flanks 4d of the teeth 36 and tooth flanks 42 of the teeth 38 are illustrated .in FIGURE 19 as in interference relationship at the tooth flank side of the acute included angle corners 24 of the teeth. Accordingly, the metal at the flank side of the acute included angle corners will be displaced by the chamfering

teeth

38 and 40 to extend beyond the end surfaces 14 and 16 of the gear teeth. This material is removed by a cutting operation, later to be described.

Alternatively, and as at present preferred, the gear chamfering means comprises a toothed rotary member which may be considered as an assembly of a helical gear conjugate to the work gear and two spur gears at opposite sides of the helical gear and having the ends of the teeth of the several gears aligned. This arrangement is illustrated in FIGURES 20 and 21 where the work gear is designated at 46 having helical teeth 48, the acute end corners 56 of which it is desired to chamfer. The chamfering means in its entirety is designated 52 and comprises a spur tooth portion 54, a helical tooth portion 56 and a second spur tooth portion 53. As indicated in FIGURE 20, the axial extent of the helical tooth portion 56 is greater than the axial extent or width of the work gear 46 so that the ends of the teeth of the work gear, in the relationship illustrated in FIGURE 20, are spaced inwardly from the adjacent end portions of the helical gear-

like members

54 and 58.

With this arrangement the operation involves feeding the gear and chamfering means toward each other in a direction radial of the work gear to a predetermined depth, which may be a full depth condition or not, as desired. Thereafter, a relative chamfering feed is provided between the work gear and the tooth chamfering means in a direction parallel to the axis of the-work gear. This causes the corresponding ends of all of the teeth of the work gear to move toward and ultimately into an interfering engagement with the spur teeth at one side of the helical toothed guide portion or gear 56.

This condition of interference is illustrated in FIGURE 21 where it will be observed that the work gear 46 has moved relative to the chamfering means indicated generally at 52 to the right in this figure so that the acute included angle end corner portions 50 of its teeth 48 have been chamfered as indicated at 60, this having been accomplished by an endwise displacement of metal which produces burrs indicated at 62.

It is of course apparent that the diagonally opposite acute included angle end corner portions 50 of the helical gear teeth 48 are chamfered by reversing the direction of chamfering feed so that the end'portions of the teeth 48 enter into the tooth spaces of the chamfering tool or gear 54.

It will of course further be observed thatthe amount of chamfer is controlled by the amount of feed. Also, the angle at which the cha mfered surface extends can be controlled by the selection of the lead or helix angle of the teeth of the chamfering gears or rolls 54, 58.

In FIGURE 20 the helical teeth 48 of the work gear are illustrated as in tight mesh with the helical teeth of the intermediate guide gear or roll 56. However, this is not a necessary condition and if the infeed is termin-ated while the teeth of the work gear and the toothed portions of the guide gear or roll are in loose mesh, relative feed between cham-fering means and the work gear in a direction parallel to the axis of the work gear will produce chamfering since the cramped engagement between the acute included angle corners of the gear teeth at the flank side thereof will cause the helical teeth of the guide roll of the chamfering means to engage the sides of the work gear opposite to the sides undergoing chamfering.

Referring now to FIGURE 22 there is illustrated

deburring cutters

63 and 64 mounted on a shaft 65 and driven in rotation by suitable means. The

cutters

63 and 64 have deburring teeth diagrammatically illustrated at 66 and the cutters are engageable alternately with opposite sides of a work gear 6'7. The

deburring cutters

63 and 64 are rotably mounted in a fixed position relative to the support for the chamfering means 68 comprising a guide roll 69 and chamfering rolls 70. The deburring cutters are spaced apart a distance such that the relative axial feed between the chamfering means and work gear brings one or the other of the

deburring cutters

63 and 64 into engagement with the flat side of the gear 6'7, or more specifically, with the flat end surfaces of its teeth, one of which is diagrammatically indicated at 71, so as to remove the burrs formed by the metal 6 displaced beyond the ends of the teeth during the chamfering operation. With this arrangement it will of course be apparent that as the burrs are initially formed the chamfering cutters are spaced from the ends of the teeth. During the end of a chamfering cycle as one of the cutters 63 or 64- approaches the ends of the teeth, it will eventually start to remove the burrs formed by the displaced metal. The final few displacement operations are each accompanied by a removal of the burrs to an increased depth, the end of the operation taking place with the cutter rotating in cutting contact with the end surfaces of the teeth.

As illustrated in FIGURE 23, the operation diagrammatically illustrated in FIGURE 19 and described in the foregoing, employs deburring

cutters

72 and 74 keyed to a drive shaft 76 for simultaneous rotation. These cutters are urged towards each other by compression springs 78 and the approach is limited by suitable means such as an abutment sleeve 80. The cutters '72 and 74 include outer annular portions 82 having inclined guide surfaces 84 such that as the cutters are moved radially into engagement with opposite sides of a gear 86 they are cammed outwardly against the compression springs 78. The cutting surfaces 88 of the cutters include flat surfaces interrupted by flutes or the like, which provide cutting edges capable of removing the burrs produced by the material displaced during the chamfering operation. With this arrangement it will of course be apparent that the burrs are continuously removed from the beginning of the chamfering operation.

Referring now to FIGURES 1-18 there is illustrated a complete machine for carrying out the chamfering and deburring operation on helical gears. The machine is illustrated in its entirety in FIGURE 1, and comprises a base having a work head 102, a tool support col umn 194, and a vertically adjustable tool carriage 106 on said column. The column is mounted for horizontal movement toward and away from the axis of rotation of a work gear carried by said work head 102. As will later appear, vertically reciprocable means carrying the chamfering rolls and the guide roll are mounted on the tool carriage 166. The work head includes a power actuated vertically movable tailstock 110 which carries the work engaging center 112.

Motor means, later to be described, are provided for driving the work gear in rotation in a fixed position about a vertical axis. The tool column 104 is power actuated as will subsequently be described, to move the toothed chamfering means into meshed engagement with a work gear carried by the work head 102. The tool carriage 166 is adjusted to the appropriate position for the particular work piece and the rotatable toothed chamfering means is moved into meshing engagement with the teeth of the gear at a mid-position with respect to vertical movement relative thereto. Forward movement of the tool column 194 is arrested by adjustable abutment means. Thereafter, while the work gear is positively driven in rotation and causes rotation of the toothed chamfering means through the meshed engagement with the Work gear, the chamfering means is moved vertically to limiting positions above and below its intermediate position and return to its intermediate position. This vertical movement of the chamfering means results in chanrfering of the acute included angle corners of the helical teeth of the work gear at a flank side thereof and a displacement of metal beyond the ends of the teeth of the work gear. A pair of deburring cutters are movable vertically with the toothed chamfering means and these are driven in rotation during the chamfering operation. Since the cutters are movable with the chamfering means they may be initially positioned so that at the limit of upward and downward movement of the chamfering means they may move into registering position with the end surfaces of the teeth of the work gear.

As best seen in i TGURE 2, a motor 114 is provided which drives rotary work support means in rotation, and a motor 116 is provided for driving the deburring cutters in rotation.

Referring now to FIGURES 35 the detailed construction of the base 1% is illustrated. The drive means for the work piece comprises the motor 114 previously described which is connected by means of a belt 118 to a pulley 12th carried by a shaft 122 which drives a worm 124 in mesh with a worm gear 126 keyed or otherwise secured to the vertical work spindle 123. At its upper end the work spindle 125 is provided with an adapter 136 for connection to a particular work piece.

The motor 114 is bolted to a mounting plate 132 as indicated at 134 and the mounting plate is connected for vertical adjustment on the base lit? by means of screws 13:5 extending through elongated slots in the mounting plate 152. The position of the plate 132 is determined by an adjusting screw 138 extending through a threaded bracket 14!) carried by the plate and having an end engaging a fixed bracket 142 on the base 100. By this device tension of the belt 118 may be readily adjusted.

The base 195) is provided with a projection 144 on the upper surface of which the tool column 104 is mounted for adjustment, as will subsequently be described.

Referring now to FIGURES 68 the work head 162 comprises a pedestal 146 adapted to be fixedly mounted to the top of the base 106). This pedestal is in the form of a hollow casting having a .top wall 148, a bottom wall 1%, and extending between these walls is a fixed piston rod 1 2 towhich a piston 154 is fixed by suitable means such for example as snap rings 156. The vertically movable tailstock 119 includes the work engaging center 112 as previously described, and in addition includes a cylinder portion 158 closed at its upper end by a cap 16% and closed at its lower end by a cap 162. The piston 154 is received in the cylinder.

Extending upwardly from the portion of the piston rod which carries the piston 154 are

fluid pressure passages

164 and 166 through which fluid under pressure may be admitted to the cylinder portion 158 either above or below the piston 154. Accordingly, while the piston 154 remains stationary, the cylinder portion 158 and the tailstock 116 are movable downwardly into engagement with a work piece or movable upwardly to release the work piece. Mounting means 169 for the center 112 is carried for vertical adjustment on the tailstock 110 and is retained in clamped position by means of a clamping screw 168 extending through an elongated slot 175 in the tailstock.

Extending from the cylinder portion 158 in a direction opposite to that of the tailstock 119 is a projection 172 extending through an opening 174 in the pedestal 146. Rails 1% are connected to the rear side of the pedestal 146 and control switches 178 and lfitl are carried thereby. Switch actuators 182 are mounted in adjustable positions at the rear of the projection 172 and actuate the switches 1'78 and 18% at the ends of vertical movement of the tailstock 110.

Referring now to FIGURES 9l2, details of the tool column 104 and related structure are shown. The tool column 1% is mounted on suitable ways 184 provided at the top of the base 1% for reciprocation horizontally in a direction radial of the axis of rotation of a work piece carried by the work support head 102. The means for reciprocating the tool column 104 comprises a fixed piston 186 carried at the end of a piston rod 188 which is fixedly secured to a bracket 1% at the top of the base 1%. The lower portion of the column 104 is provided with a cylinder 192 in which the stationary piston 186 is received. Passages for the admission of fluid pressure are provided which extend to opposite sides of the cylinder 1&2, one of these being a drilled passage 1.94 and the other com prising a conduit 1% extending from a passage 1% to a fitting 2% and thence through drilled passageways NZ to one end of the cylinder.

Admission of fluidunder pressure to the cylinder 192 is controlled by suitable valves, not shown, but control of the valves is by means of suitable switch means responsive to horizontal travel of the columrrlltM. For this purpose a rail 204 is provided extending along one side of the pedestal in parallelism to the direction of the ways 184. Mounted in fixed position at the upper side of the base is a switch 206 and adjustable switch actuating dogs 208 and 21d are provided on the rail in position to actuate switch 2% at predetermined positions of travel of the tool column 104.

Adjustable means are also provided for the purpose of limiting the forward position of the tool column 104 and this means comprises a rigid abutment 212 fixed to one side of the tool column 1494 engageable with an abutment screw 214 carried by a bracket 216 aflixed to the base 1%. By appropriate adjustment of the abutment screw 214, forward travel of the tool column 164 may be limited to a position in which the toothed chamfering rolls and the toothed guide roll, it used, may have a predetermined amount of backlash with reference to the teeth of the work gear.

In an alternative operation the rigid abutment means limiting forward movement of'the tool column 104 may be adjusted to a'position 'such that upon completion of the forward movement thereof, the teeth of the work gear will be chamfered without the necessity of a relative reciprocation parallel to the axis of the Work gear, as has previously been suggested. It will also be apparent that the chamfering operation can be carried out to a predetermined depth omitting the stop means, by limiting the pressure which is applied to the cylinder 192, where chamfering is the result of radial feed rather than axial feed.

Means are provided at the side of the tool column 104 to mount the tool carriage MP6 for vertical adjustment. A forwardly projecting guide portion 220 is provided having laterally extending

guide ribs

222 and 224. Intermediate these guide ribs there is provided a vertical adjustment screw 226 which is mounted for rotation and retained against axial movement by suitable mounting structure indicated generally at 228. Atits upper end the screw 226 is provided with a square head 230 which permits rotation of the screw by application of a suitable tool thereto. In FIGURE 11 there is shown a feed nut 232 adapted to be bolted or otherwise rigidly secured to the vertically adjustable tool carriage as will now be described.

Referring now to FIGURES 13-16 the vertically adjustable tool carriage 106 is adapted to be mounted by gibs 234 and 236 to the rails or

ribs

222 and 224 provided on the tool columnllld. The nut 252, whose position is indicated in FIGURE 11, is shown in FIGURE 14 and it is to be understood that this nut is rigidly bolted to the vertically adjustable tool carriage 1%. The tool carriage 166 includes a vertical cylindrical passage or bore 238 for the reception of a deburring cutter spindle housing 24%) which receives the deburring cutter spindle 241 therein for rotation. The spindle housing 240 is mounted in the passage 23$ for a limited vertical movement. The tool carriage 1% also includes as a separable component clamped thereto a bracket 24-2 having a tubular bore 244 therein for receiving a vertically movable spindle housing 246 which carries the freely rotatable spindle 248 adapted to mount the rotatable toothed chamfering means at its lower end.

Means are provided for effecting rotation of the deburring cutter spindle 241 and this means comprises the gear 250 keyed or otherwise secured thereto and in mesh with a drive gear 252 carried by a shaft 254 suitably journaled in the tool carriage 1G5. It will be observed that the drive gear 252 is substantially Wider than the gear 250 and therefore permits limited vertical movement of the spindle 241 together with its housing 2- .6 in the cylindrical passage 23d.

I Rotation is imparted to the drive gear through a worm gear 256 and a worm 258 carried by a shaft 260 which in turn is connected to the drive shaft of the cutter drive motor 116 (FIGURE 2) by coupling means indicated at 262.

In the preferred operation of the machine it will be recalled that after the gear cham-fering means has been moved into meshed engagement with the work gear, the chamfering rolls are located at opposite sides of the work gear and spaced somewhat beyond the ends of its teeth. The chamfering operation is then completed by moving the chamfering means vertically from an intermediate position to a limiting upward position and a limiting downward position, each of which results in chamfering one end of ,the teeth of the work gear. The means for insuring that the chamfering means and, in normal operation the deburring cutters, occupy an intermediate position between vertical upper and lower limits of movement during horizontal travel of the tool column 104, is best illustrated in FIGUREIS. As seen in this figure, the tool carriage 1% is provided with a stepped cylinder comprising an enlarged upper cylinder portion 264 and a relatively reduced lower cylinder portion 266. Extending through this stepped cylinder is a piston rod 268 having a piston 270 formed thereon or afiixed thereto which is verticallymovable in the reduced lower cylinder portion .266. Surrounding the portion of the piston rod 268 above the piston 27% is a freely slidable piston 271 dimensioned to fit Within the enlarged upper cylinder portion 264. The upper end of the stepped cylinder is closed by a plate 272 through which the upper end of the piston stepped cylinder above the piston 271, are illustrated in dotted lines in this figure. It will be apparent that when pressure is admitted only to the space above the piston 270, the piston 270 is moved downwardly, until the piston 27% engages the bottom of the relatively small lower cylinder 266 or other abutment means limiting the movement of the piston rod, this determining the lowermost "position of the piston rod 268.

When pressure is admitted only to the space below the piston 270, the

pistons

270 and 271 are urged upwardly until the piston 271 engages the adjacent portion of the plate 272, this determining the maximum upward position of the piston rod 268. When pressure is admitted both to the space above .the free sliding piston 271 and below the piston 270 at the same pressure, the relatively larger area of the free sliding piston 271 moves it downwardly until its peripheral portion engages the shoulder at the junction between the lower end of the upper cylinder and the upper end of the lower cylinder. At the same time, the fluid under pressure moves the piston 270 upwardly into engagement with the free sliding piston 271 as shown. This determines the intermediate position of the piston rod 268.

' At its lower end the piston rod 268 carries a horizontally extending bar or key 274 opposite ends of which are received in recesses provided in the spindle housings '240 and 246. Suitable clearance for the key 274 is provided which permits vertical movement thereof from the intermediate position illustrated in FIGURE 15 to the limiting upward and lower vertical positions as previously described.

Located within a removable cap 276 are limit swtiches 278 adapted to be actuated upon appropriate vertical movement of the piston rod 268 by adjustable switch :actuating screws 289 carried by a bar 282 extending laterally from the upper end of the piston rod 268.

The machine as just described is particularly suitable for automatic operation in which a succession of work gears are brought by automatic loading structure into position intermediate the work drive spindle and the work center 112, at which time pressure is admitted through the passage 166 to move the center downwardly to engage the upper end of the work gear. Upon completion of the chamfering and deburring operation the work center 112 moves upwardly and releases the chamfered work gear, at which time it may be removed by the automatic loading movement and replaced with a second work gear. In general, all of the successive operations generate appropriate signals which are used to initiate the next step of the sequence.

in order to employ the machine in its preferred operation the sequence of steps is as follows: In the first place, correct deburring cutters are selected and assembled on the cutter spindle 241 with the proper spacing therebetween. The work gear is then positioned on the work holding fixture and fluid pressure is admitted to the tailstock cylinder portion 158 to move the work engaging center downwardly to fix the work piece in operating position. At this time the deburring cutter spindle 241 and the chamfering spindle 240 are moved into the center position by admitting fluid under pressure both to the space above the free sliding piston 271 and below the piston 270 fixed to the piston rod 268. Thereafter, the tool column 1% is jogged forwardly until the cutters and rolls are near the work. Thereafter, the

deburring cutters

63 and 64 and the rolls 7@ (FIGURE 22) are moved vertically by means of the adjusting screw 236 until they are equally spaced at opposite sides of the work piece. With the deburring cutters thus approximately centralized, the next step is to move the tool column 134 forwardly to a position in which the deburring cutters extend beyond the outer periphery of the work gear. Thereafter, the cutter and roll spindles are jogged downwardly until the upper deburring cutter engages the top face of the gear and the appropriate switch actuating screw 280 isadjusted to actuate the appropriate micro switch 278. A corresponding adjustment is made for the upper position of the deburring cutters. Thereafter, the deburring cutters, together with the chamfering rolls are set back to center position, after which the tool column 104- is moved inwardly until the guide roll 69 or the chamfering rolls 70 are in slight backlash. At this time the forward dead stop screw 214 is adjusted to insure that subsequent forward movement of the tool column 104 will be arrested in this position. At this time the appropriate adjustments have been completed and the machine is ready for automatic cycling.

In the operation the guide roll of the chamfering means advances into loose mesh with the teeth of the work gear, the two chamfering rolls being located slight- 'ly beyond the ends of the teeth of the work gear, or

in other words, slightly beyond the opposite sides of the work gear. Forward movement of the cham'fering means is arrested by the abutment mechanism. Rotation imparted directly to the work gear is transmitted to the chamfering means'resul-ting in meshed rotation of the teeth of the work gear with the teeth of the guide roll. The teeth of the chamfering rolls are conjugate to the teeth of the work gear except for lead and each of the chamfe-ring rolls has tooth surfaces extending at a different lead from that of the work gear, the lead of the teeth of the chamfering rolls being selected to produce the required chamfer on the teeth of the work gear. With the work gear and guide roll rotating in mesh relative vertical movement is imparted first in one direction and then in the opposite direction to the spindles carrying the deburring cutters and the chamfering means. This causes the ends of the teeth of the work gear to enter into an interference condition with the teeth of the chamfering rolls, this resulting in pressure at the flank side of the gear teeth at the acute included angle corner portions thereof with a resultant formation of the desired chamfer and a corresponding displacement of metal beyond the ends of the teeth, thus producing burrs. These 1 l burrs are removed in the same operation by the deburring cutters.

With the same machine it is possible to provide a chamfering operation by a method which eliminates the necessity for vertical feed of the deburring cutter and the chamfering roll spindles. In this method the chamfering rolls, either with or without an intermediate guide roll, are mounted on the chamfering roll spindle but are spaced 2 part a distance somewhat less than the width of the work gear. Thus, as the chamfering rolls are moved radially or substantially radially into mesh with the work gear, interference develops during this movement between the acute included angle corner portions of the teeth of the work gear at the flank side thereof and the adjacent tooth surfaces of the chamfering rolls. The amount of chamfer in this case is determined by the depth of approximate radial feed of the spindles toward the work gear. The operation may be terminated by dead stop abutment means limiting further advance of the tool column, or it may be limited by the control of pressure supplied to the cylinder which causes advance of the tool column.

In any case, the present invention is characterized generaiiy by the provision of a chamfer resulting from the application of pressure at thefiank side of the acute included angle corner portions of the helical gear teeth with a resulting displacement of metal to produce a chamfer, the displacement of metal simultaneously producing burrs which extend beyond the ends of the teeth Preferably, this application of pressure on each tooth is caused to progress along the corner portion thereof from crest to root or vice versa, and is further carried out in a multiplicity of successive pressure applications. This last results from the application of pressure through engagement with a rotating toothed chamfering tool during continued feed in a direction appropriate to cause further displacement of metal on each tooth as it passes through the zone of mesh. The removal of the burrs may be accomplished completely after each application of pressure or it may be carried to completion only substantially coincident with the final application of pressure to the gear teeth.

The drawings and the foregoing specification constitute a description of the improved method and apparatus for chamfering gear teeth in such fuil, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary Work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said Work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said charnfering means comprising guide tooth portions conjugate to the teeth of the work gear and chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the helical teeth of the work gear and effective to chamfer the acute angled corners of the teeth of the Work gear by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports in a direction parallel to the axis of rotation of said work support to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear, and cutting means engaging the ends of the teeth of the work gear to remove the metal displaced beyond the ends thereof.

2. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said chamfering means comprising a guide roll having teeth conjugate to the teeth of the work gear and chamfering rolls at each side of said guide roll, said guide roll having a width at least as great as the width of the work gear, said chanifering rolls having teeth provided with chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the teeth of the work gear and effective to chamfer the acute angled corners thereof by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports parallel to the axis of the work gear to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear, and cutting means engaging the ends of the teeth of the work gear to remove the metal displaced beyond the ends thereof.

3. A gear cha-mfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatabie in mesh with a heiicai work gear on said work support, said chamfering means comprising a guide roll having teeth conjugate to the teeth of the work gear and charnfering rolls at each side of said guide rolls, said guide roll having a width at lea-st as great as the width of the Work gear, said chamfering rolls having teeth provided with chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the teeth of the work gear and effective to chamfer the acute angled corners thereof by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports parallel to the axis of the work gear to establish a pressure contact between the charnfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear, and cutting means comprising rotary cutters spaced apart at opposite sides of the work gear, said cutters being mounted in fixed positions relative to said tool support and hence relatively movable therewith respectively toward and away from opposite sides of the work gear and engageable with the end-s of the teeth of the work gear to remove the metal displaced beyond the ends thereof.

4. A gear chamfering machine for charn fering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said Work support, said chamfering means comprising a guide roll having teeth conjugate to the teeth of the work gear and chamfering rolls at each side of said guide roil, said guide roll having a width at least as great as the width of the work gear, said chamfering rolls having teeth provided with chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the teeth of the work gear and effective to chamfer the acute angled corners thereof by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports parallel to the axis of the work gear to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the Work gear, and cutting means comprising rotary cutters at opposite sides of the work gear and in cutting engagement with the end surfaces of the teeth of the gear to remove metal as it is displaced beyond the tooth ends by said chamfering rolls.

5. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said chamfering means comprising a guide roll having teeth conjugate to the teeth of the work gear and chamfering rolls at each side of said guide roll, said guide roll having a width at least as great as the width of the work gear, said chamfering rolls having teeth provided with chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the teeth of the work gear and effective to chamfer the acute angled corners thereof by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports parallel to the axis of the work gear to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear, cutting means comprising rotary cutters at opposite sides of the work gear, and yieldable means urging said cutters into cutting engagement with the end surfaces of the teeth of the gear to remove metal as it is displaced beyond the tooth ends by said chamfering rolls.

6. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said chamfering means comprising guide tooth portions conjugate to the teeth of the work gear and chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the helical teeth of the work gear and effective to chamfer the acute angled corners of the teeth of the work gear by the application of pressure thereto, means for driving one of said supports in rotation, and means for feeding one of said supports in a direction parallel to the axis of rotation of said work support to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear.

7. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support having its axis of rotation parallel to the axis of rotation of said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said chamfering means comprising a guide roll having teeth conjugate to the teeth of the work gear and chamfering rolls at each side of said guide roll, said guide roll having a width at least as great as the width of the work gear, said chamfering rolls having teeth provided with chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead diiferent from the lead of the teeth of the work gear and effective to chamfer the acute angled corners thereof by the application of pressure thereto, means for driving one of said supports in rotation, and means for feeding one of said supports parallel to the axis of the work gear to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear.

8. A gear chamfering machine for chamfering the acute end corners formed by the intersection between the flank and end surfaces of the teeth of a helical gear which comprises a rotary work support, a rotary tool support adjacent said work support, toothed chamfering means on said tool support rotatable in mesh with a helical work gear on said work support, said chamfering means comprising guide tooth portions conjugate to the teeth of the work gear and chamfering tooth portions generally conjugate to the teeth of the work gear except for lead and extending at a lead different from the lead of the helical teeth of the work gear and effective to chamfer the acute angled corners of the teeth of the Work gear by the application of pressure thereto, means for driving one of said supports in rotation, means for feeding one of said supports in a direction parallel to the axis of rotation of said work support to establish a pressure contact between the chamfering tooth portions and the tooth flank side of the acute angled corners of the teeth of the work gear to chamfer them by displacing metal beyond the end surfaces of the teeth of the work gear, and cutting means engaging the ends of the teeth of the work gear to remove the metal displaced beyond the ends thereof.

9. Deburring and chamfering apparatus for helical gears comprising a rotary work support, a rotary tool support adjacent said work support, chamfering means on said tool support effective to chamfer the acute angled corners of the teeth of a work gear and to form burrs thereon extending beyond the ends of the gear teeth, means for driving one of said supports in rotation, means for feeding one of said supports parallel to the axis of the work gear, and deburring means comprising rotary cutters spaced apart at opposite sides of the work gear, said cutters being mounted in fixed positions relative to said tool support and hence relatively movable therewith respectively toward and away from opposite sides of the work gear and engageable with the ends of the teeth of the work gear to remove burrs displaced beyond the ends thereof by the chamfering means.

References Cited by the Examiner UNITED STATES PATENTS 1,578,589 3/1926 Earl 1.4 2,157,981 5/1939 Drummond 901.4 2,206,443 7/1940 Barter et al. 901.4 2,206,450 7/1940 Christman 901.4 2,683,399 7/1954 Dodge 901.4 3,014,274 12/1961 Callaghan 29556 FOREIGN PATENTS 698,122 10/1953 Great Britain.

WILLIAM W. DYER, JR., Primary Examiner.

Claims

1. A GEAR CHAMFERING MACHINE FOR CHAMFERING THE ACUTE END CORNERS FORMED BY THE INTERSECTION BETWEEN THE FLANK AND END SURFACES OF THE TEETH OF A HEILCAL GEAR WHICH COMPRISES A ROTARY WORK SUPPORT, A ROTARY TOOL SUPPORT HAVING ITS AXIS OF ROTATION PARALLEL TO THE AXIS OF ROTATION OF SAID WORK SUPPORT TOOTHED CHAMFERING MEANS ON SAID TOOL SUPPORT ROTATABLE IN MESH WITH A HELICAL WORK GEAR ON SAID WORK SUPPORT, SAID CHAMFERING MEANS COMPRISING GUIDE TOOTH PORTIONS CONJUGATE TO THE TEETH OF THE WORK GEAR AND CHAMFERING TOOTH PORTIONS GENERALLY CONJUGATE TO THE TEETH OF THE WORK GEAR EXCEPT FOR LEAD AND EXTENDING AT A LEAD DIFFERENT FROM THE LEAD OF THE HELICAL TEETH OF THE WORK GEAR AND EFFECTIVE TO CHAMFER THE ACUTE ANGLED CORNERS OF THE TEETH OF THE WORK GEAR BY THE APPLICATION OF PRESSURE THERETO, MEANS FOR DRIVING ONE OF SAID SUPPORTS IN ROTATION, MEANS FOR DRIVONE OF SAID SUPPORTS IN A DIRECTION PARALLEL TO THE AXIS OF ROTATION OF SAID WORK SUPPORT TO ESTABLISH A PRESSURE CONTACT BETWEEN THE CHAMFERING TOOTH PORTIONS AND THE TOOTH FLANK SIDE OF THE ACUTE ANGLED CORNERS OF THE TEETH OF THE WORK GEAR TO CHAMFER THEN BY DISPLACING METAL BEYOND THE END SURFACES OF THE TEETH OF THE WORK GEAR, AND CUTTING MEANS ENGAGING THE ENDS OF THE TEETH OF THE WORK GEAR TO REMOVE THE METAL DISPLACED BEYOND THE ENDS THEREOF.