US2232408A - Gear finishing machine - Google Patents

Description

Feb. 18, 1941.:

S. M. SHAW GEAR FINISHING MACHINE Fil ed Nov. 425, 1935 3 Sheets-Sheet 1 v INVENTOR.

szawzf M 51m ATTORNEYS) Feb. is 1941.

(s. M. sHAw GEAR FIN ISHING MACHINE 3 Sheets-Shet 2 Filed NOV. 25, 1935 V YI'NVENTOR. fiianie g M 5kam ATTORNEYS.

' 28, 1941. SMS 'A 2 2,232,408

emu; rmsaxu MACHINE Filed Nov. 25, 1935 2 I s Sheets-Shef. s I 2 v INVENTOR Stanley/M 511mm BY W 9' 76 444" 1 TTORNEYG.

Patented Pa. 18, 1941 UNITED STATES.

GEAR FINISHING MACHINE Stanley M. Shaw, Detroit, Mich assignor to Michigan Tool Company, a corporation of Dclaware Application-November 25 1935', Serial No. 51,401

6 Claims.

I 5 'vide a simplified machine for accurately machining and finishing gears to proper tooth form and diameter.

It is a further object of the present invention to provide a machine embodying means to feed a gear transversely across the plane of rotation of a finishing tool to thereby accurately machine the teeth of such gear and to effect uniform wear throughout the surface of the tool teeth.

15 It is a further object of the present invention to provide a machine of the last mentioned type which embodies a pair of spaced finishing tools, between which the gear is moved across the face of the tool teeth.

2 It is a further object of the present invention to provide a finishing machine embodying two rotating finishing tools spaced apart such a distance that a gear passing therebetween transverse to the plane of rotation of such tools may be finished to accurate dimensions.

It isa further object of. the present invention to provide a machine of the last mentioned type in which one of the tools may be driven to correspondingly drive the gear and the second tool and embodying means to suitably load or brake such second tool.

It is a further object of the present invention to provide a gear finishing machine embodying means to tilt one or both of the tools to positions in which the axes of the tilted tool or tools and the gear are at an angle to each other, and

embodying additional means to move the gear transversely across the face of the tools.

It is a further object of the present invention to provide a gear finishing machine which is sim. ple in'construction, accurate in machining and economical of manufacture. I

Other objects and advantages of the present invention appear in the following description and in the appended claims. 1

In the drawings, throughout the several views of which corresponding reference characters are" used to designate corresponding parts, Figure 1 is a view in sideelevation of an illusgo-trative gear finishing machine embodying the present invention;

. of thestructure shown Fig. 4 is a detail view illustrating finishing tool;

Fig. 5 is a fragmentary view illustrative of a lapping tool which may be used in the practice of the present invention; and 5 Fig. 6 is an enlarged fragmentary view corresponding to Fig. 4.

It has been found, in connection with the finishing of gears of either spur or helical type, through lapping, shaving. or burnishing opera- 10 tions, that the deformation of the gear teeth caused at the pitch line thereof by the s ipping between the gear teeth and the tool teeth which occurs on each side of the pitch line. may be compensated foror eliminated by running thegear with a tool having an axis at an angle to the axis of the gear, which angle varies somewhat in accordance with the type of gear being finished. By disposing the axes of the gear and tool at an a form of angle in this manner, a lateral component of movement is introduced between the tool teeth and the gear teeth which compensates for and prevents the deforming of the gear teeth at the pitch line. In connection with shaving operations, the co-pending application of W. F. Dalzen, Serial No. 554,193, filed July 13, 1931, assigned to the same assignee as the present application,

- discloses tools through use of which any cutting action or finishing action due t the roll of the gear and of the tool may be eliminated, and the machining effected entirely through the lateral component of movement between the tool and the gear. In accordance with this application, the gear teeth comprise aseries of spaced lands, separated by grooves, and the lateral forward edges of the lands are formed as cutting edges which are efiective to cut entirely due to the lateral component of. movement.

, The improved gear finishing machine of the present invention provides for introducing an additional component of lateral movement between the gear and the finishing tool, which has been found to make any wear on the teeth of the lapping, burnishing or shaving tools uniform over the tooth surfaces, thus prolonging the efiective life of the tool and improving the finishing action as a whole.

In the form illustrated, the gear finishing machine of the present invention comprises generally a pair ofrotatably supported finishing 5 tools, which may be of either the spur or helical type, and a table disposed to reciprocate a gear between said tools in a path transverse to the plane of rotation thereof. The two finishing tools may be positioned in spaced co-planar relationship and in a plane parallel to the plane of the gear being finished, but preferably are tilted respectively at a predetermined angle to the plane of the gear, thusintroducing the above mentioned lateral component of movement between the gear teeth and the tool teeth, and compensating for the tendency to deform the gear teeth due to the roll of the gear. In finishing gears of the spur type, the teeth of the cutting tools are formed at an angle equal to such tilting angle. Where the gear being finished is of thehelicaltype,the angles of the teeth on the cutting tools are preferably greater than and less than the angle of the teeth on the gear by the amount of the tilting angle. That is to say, if the teeth of the gear are disposed on a ting tool may have the teeth disposed at an angle of thirty degrees and the other tool may have the teeth disposed at an angle of sixty degrees, the tilting angle of the axes of the tools with respect to the axis of the gear being fifteen degrees. As mentioned above, this angular difference varies, depending upon the type of the gear and teeth to be finished.

The gear to be finished is supported in mating relation to the tools and between them, and is preferably continuously reciprocated in the previously mentioned transverse path. This transverse or lateral motion introduces a continuous and additional lateral component of movement between the teeth of the gear and of the tools and renders the wear on the tool teeth uniform over the surface thereof, and also produces an accurate finishing of the gear teeth from the crown, through the root and pitch lines thereof.

The transverse or lateral movement of the gear may be effected in various ways. Preferably, and as illustrated, this movement is effected automatically and continuously in timed relation to the rotation of the tools. With this arrangement, an entirely automatic machine results.

In the form illustrated, the tool supports are adjustable both inwardly and outwardly with respect to the gear support, to thereby accommodate the machine to diflerent sizes of gears, and are also adjustable in a direction parallel to the path of movement of the gear. With this arrangement, a plurality of individual gears, or a gear cluster, may of the tools may also be effected in either direction with respect to the axis of the tool, in the illustrated form of the present invention. Because of this feature, the gear may be selectively rotated in either direction, and either right or left-handed tools may be used.

Considering the above mentioned elements in more detail, and referring to the drawings, a pair of similarly formed finishing tools I6 and I2 are rotatably supported upon shafts l4 and I6 respectively, for effecting a finishing operation upon an illustrative gear l6.

Gear i6 is rotatably carried on a shaft 26 which is supported between stocks 22 and 24. Stocks 22 and 24 are slidably supported upon ways formed in a supporting bed 26 and may be locked in position thereon by the usual lock nuts 21. Bed 26 is also provided with guides 26 through which it is slidably supported on ways 36 formed in the machine frame, along which bed 26 and consequently gear l6 may be laterally moved, preferably automatically, and in timed relation to the rotation of tools l6 and I2.

The details of the mechanism for acoomplishing the automatic lateral movement of gear I6 and bed 26 form no part of the present invention,

forty-five degree angle, the one cut-- be operated upon. The tilting.

and may be arranged in various ways. As illustrated, a fluid pressure controlled cylinder 32 is suitably supported within the machine frame and is provided with a piston rod 34 which is secured by nut 38 to a boss 36 extending downwardly from the underside of bed 26. Reciprocating movement of piston rod 34 effects a corresponding reciprocating movement of bed 26 and of gear i6.

The fluid connections for cylinder 32 preferably include a valve 46 of conventional reversing type, having lines 4| and 43 for connecting to cylinder 32 and concentric supply and exhaust lines 45 for connection to a source of fluid pressure which may comprise a pump 56 driven by a motor 62. Valve 46 is supported on the machine frame with the control arm 42 thereof in cooperative relation to a pair of cams 44 and 46 which are secured to bed plate 26. The relation is such that as bed plate 26 reaches one limit of travel, the cam 46 engages arm 42 and swings it to a position in which valve 46 is effective to complete fluid pressure connections to cylinder 32 to cause bed plate 26 to travel in the opposite direction.

Upon reaching the opposite limit of travel, cam 44 engages arm 42 and swings it to the first position, completing fluid pressure connections through valve 46 for cylinder 32 effective to cause the original direction of movement of bed plate 26.. With this arrangement, it will be understood that bed plate' 26 and consequently gear l6 may be caused to reciprocate continuously along the horizontal path illustrated, and may be stopped at any desired point by interrupting the fluid supply. This may be accomplished, for example, by opening the illustrative control switch 56 for motor 52.

It will be understood that the spacing between cams 44 and 46 is such that the travel of bed 26 is slightly less than the width of the tools l6 and I2, so that the latter are maintained in continuous mating relation with the. gear l8. One or both of cams 44*"and 46 are adjustable to accommodate the machine to gears of different width as well as to gear clusters.

The shaft l6 upon which the finishing tool I2 is secured for rotation thereby also carries a worm wheel 66 which mates with a worm gear 62.

Worm gear 62 is supported on a shaft 64 which also carries a spur gear 66 positioned in mating relation with a corresponding spur gear 66. Spur gear 66 is mounted on the outer end of the shaft 16 of a suitable fluid motor I2, the frame 14 of which is rotatably supported within a bracket 16. A suitable locking stud I6 is provided to lock frame 14 in any predetermined rotative position with respect to bracket 16. It will be noted that the shell 66 within which shaft l6 and tool l2 are supported, as well as the housing 66 which forms, a support for the worm gear'shaft 64, are both rigidly connected to the motor frame 14 so that rotation of frame 14 results in tilting finishing tool 12 with respect to the plane of gear l6.

Motor 12 may be driven in any suitable manner from pump 66, illustrative connections including the lines 62 and 66, and the reversing valve 64. The intermediate connections form no part of the present invention and have not been illustrated. It will be understood that the lines 62 and 66 may include flexible portions in order to permit the above mentioned rotative movements of the frame 14 of motor 12 within bracket Bracket I6 is provided with a dove-tail 66, which rides in a corresponding guide-way 62 formed in a supporting bed 64. The position of bracket I6 along guide-way 92 may be suitably formed integrally therewith, and a guide-way I which may be formed in the machine frame. A

corresponding lead screw I02 is provided to eifect this adjustment.

The shaft I4, which is driven by the finishing tool I0 is connected to the shaft I08 through intermediate gearing in all respects as described in connection with gear I2. Shaft I08 carries ,afluid brake II4 of conventional construction,

the shoes II8 of which cooperate with an associated housing IIB. Housing Hi, to which the shell III! for tool I0 and shaft I4 is secured, is rotatably supported in a bracket H2 and may be locked in place with respect thereto by stud III. A suitable flexible supply line for brake I I4 is illustrated at I20 and may be suitably conchine as a whole, it will be understood that in beginning a finishing operation, tools Ill and I2 are adjusted through transverse movement of their supporting brackets H2 and I6 to a position of proper radial spacing with gear I8. In finishing a'slngle gear I8, it will also be understood that tools III and I2 are adjusted in a direction parallel to the path of reciprocation of gear I8 so that both tools engage gear III. In finishing a plurality of gears, such as clusters, it will be understood that tools I. and I2 may be offset throughtheir independent adjustments, so that one of them acts upon one of the gears of the cluster, and the other acts upon a second gear of the cluster;

Upon the starting of motor 52, pump 50 eii'ects continuous reciprocation of gearIO on bed 26, through the reversing valve 40, and drives tool I2 continuously, through reversing valve 84 and motor I2.

Tool I2 drives gear I8, and the latter correspondingly drives tool III. In certain operations, such as shaving operations, the tool teeth are thinner than required for usual mating with the teeth of gear I8, and in such instances, it

is considered desirable to impose a braking load on the driven tool III. This may be accomplished, as previously described, through the adjustable brake I I4, the adjustment of which may conveniently be read upon an indicating meter I24.

The machine may be operated with the parts in the relative positions shown in Figure 1, in which tools III and I2 and gear I! rotate in parallel planes. Preferably, however, and as previously mentioned, the tools III and I2 are tilted with respect to the axis of gear I8, to positions such. as shown in Figures 2 and 3. As also previously stated, the angle of tilt varies with the type and size of gear being operated upon, and is preferably such as to produce a substantial balance between the amount of cutting due to the roll, and due to the lateral component of slippage introduced by the tilting, to thereby lap or burnish substantially a uniform shape to the gear teeth. As will be understood,

a lapping or burnishing operation may be effected through use of tools having the tooth form illustrated in Figure 5. A shaving operation, however, is preferably effected through use of a tool having the tooth form shown in Figures 4 and 6, in which the individual teeth I40 of the tool each comprise a series. of spaced lands I42 separated by grooves I44. The lateral forward edges of the lands I42 are formed as cutting edges, so that the entire machining action effected by the tool occurs due to the lateral component of slippage, and no machining action is effected due to the roll of the gear.

The reciprocating movement of gear I8, the limits of which are determined by the positions of earns 44 and 46, preferably occurs at a substantially lower rate than the rate of rotation of the gear and the tools. The continuous reciprocation of gear I8 laterally of the gears brings the teeth of gear I8 successively into onoperating relationship with the entire length of the teeth of the tools III and I2, and makes the wear thereon clue to the finishing action uniform over the entire tooth faces. This uniform wear, as will be understood, prolongs the life of tools I0 and I2 and also improves the accuracy of the finishing action upon gear I8.

In finishing gear clusters, as previously mentioned, the machine is preferably operated .with one of the tools III and I2 in engagement with one gear of the cluster and the other tool in engagement with another gear of the cluster. With this-arrangement, the tooth faces of the gears are finished one side at a time, and a complete finishing operation may conveniently be effected by reversing the direction of rotation ofthe parts. This may be accomplished by reversing the connections to motor I2 through the reversing valve 84.

It'will also be noted that the arrangement of tools III and I2 so that they may be tilted independently of each other and in either direction permits the use either of two right handed or two left handed tools, or of a left handed and a right handed tool. In the latter instance, as will be understood, both tools I0 and I2 would be tilted in the same direction with respect to the gear I8.

Although a specific embodiment is shown, it will be evident that various changes may be made in the form, number and arrangement of parts within the spirit and scope thereof.

What is claimed is:

1. In a gear finishing machine, the combination of a pair of finishing tools, means for rotatably supporting said tools with their axes in spaced relationship, means for driving one of said tools and for braking the other of said tools, means for supporting a gear to be finished between said tools and in mating relation therewith respectlvely for rotation thereby, said gear and tool supporting means being arranged to support said gear and tools in such relation that the axes of the tools and gear intersect a common line which line lies in -the planes of rotation of said tools, and means for eflectlng continuous reciprocatcry motion of said gear in a path transverse to the plane of rotation of said gear and during the rotation of said gear.

2. In a gear finishing machine, the combination of a pair of finishing tools, means for rotatably supporting said tools with their axes in spaced relationship, means for supporting a gear between said tools in mating relation therewith respectively, said gear and tool supporting means being arranged to support said gear and tools in such relation that the axes of the tools and gear intersect a common line which line lies in the planes of rotation of said tools, a drive member, a braking member, means connecting one of said tools to said drive member so that said one tool drives said gear, said gear acting to drive the other of said tools, means connecting the other said tool to said braking member, and means for efiecting relative motion between said gear and said tools in a path transverse to the plane of rotation of said gear during the rotation thereof.

3. In a gear finishing machine, the combination of a work arbor for rotatably supporting a gear to be finished; means for efl'ecting reciprocation of said work arbor in a path parallel to the axis of said gear, said arbor and spindles being arranged to support the tools and gear in such relation that the axes of the tools and gear intersect a common line which line lies in the planes of rotation of the tools; first and second tool spindles for rotatably supporting first and second tools in diametrically opposed mating positions relative to said gear; a drive member connected to one of said tools for driving the same to rotate said gear, said gear acting to rotate said second tool; and a braking member connected to said second tool.

4. In a gear finishing machine, a pair of tools, heads mounted for rotational movement about their axes, shafts in said heads for supporting said tools therein, driving means connected to said shafts carried by said heads so disposed as to permit the rotation of said heads for tilting said shafts and tools without interrupting the driving connections, means for mounting a gear to be finished between said tools, said tool heads and gear mounting means being arranged to support the tools and gear in such relation that the axes of the tools and ears intersect a common line which line at all times lies in the planes 0! rotation of the tools, power means for operating the driving means of one of said tools, and load means operated by the driving means of the other of said tools, whereby the driving of one tool operates on one side of the gear teeth for driving the gear to have the opposite side of the teeth effective for driving the other tool against the load which provides uniform pressure between opposite sides of spaced teeth of the gear and the tools while driving the gear in a single direction.

5. In a gear lapping machine, means for supporting a pair of tools with their axes in spaced relation, means for supporting a gear between said tools in meshed relation therewith, said gear and tool supporting means being arranged to support said gear and tools in such relation that the axes of the tools and gear intersect a common line which line lies in the planes of rotation of said tools, means for driving one of said tools, means for loading the other of said tools to resist rotation, and means for moving said gear relative to said tools while in operating relation for spreading the engaging area over the tooth surface, whereby said gear teeth are simultaneously lapped on one side by one of said tools and on the other side by the other of said tools while driven in a single direction.

6. In a gear finishing machine, the combination of a pair of finishing tools, means for rotatably supporting said tools with their axes in spaced relationship, means for driving one of said tools and for braking the other of said tools, means for supporting a gear to be finished between said tools and in mating relation therewith respectively for rotation thereby, said gear and tool supporting means being arranged to support said gear and tools in such relation that the axes of the tools and gear intersect a common line which line lies in the planes of rotation of said tools, means for rocking said tools relative to said gear about said line as a center so as to dispose said gear and tools in crossed axes relation, and means for effecting continuous reciprocatory motion of said gear in a path transverse to the plane of rotation of said gear and during the rotation of said gear.

. STANLEY M. SHAW.

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