Harmonic drive for digital step motor

Claim 2

A motion transmitting system, comprising a pair of cooperating gears having confronting frictional surfaces projecting from normally spaced generally parallel planes, electromagnetic means for selectively deflecting sequential points of one of said gears toward and away from the other to produce sequential engagement of said frictional surfaces at instantaneously limited regions of said gears, said gears having mutually different configurations adapted to provide continued digital rotations of said one gear responsive to said deflections, a shaft, and universal joint means coupling one of said gears to said shaft, said universal joint means being arranged for wholly free axial and pivotal movement .Iadd.over at least a predetermined range of movement .Iaddend.without radial movement relative to said axis, wherein each of said frictional surfaces comprise teeth, and wherein said frictional contact is achieved by engagement of said teeth, said different configurations being produced by different numbers of teeth on said gears, wherein said cooperating gears are annular, lying along a common axis, the teeth thereof projecting from normally uncurved confronting surfaces thereof, said electromagnetic means including a magnetically permeable armature coupled to said one gear, and electromagnetic actuators disposed in circular array about said common axis, each of said actuators effective when energized to produce an electromagnetic field exerting deflecting forces on said armature and therefore on said one gear coupled thereto, wherein said armature comprises a rigid circular plate, said ring gear fastened to a planar surface thereof adjacent the periphery of said plate, a shaft extending along said axis and through said plate, normally perpendicular thereto, said plate retained on said shaft to permit relative rotation and limited angular orientation therebetween from the normally perpendicular relationship.

Claim 3

The invention according to claim 1 wherein said armature is responsive to sequential energization of said actuators in predetermined switching format to wobble about said shaft, thereby producing substantially single-point engagement between said gears, and wherein is provided a second pair of gears coupled respectively to said armature and said shaft to produce rotation of said shaft at slow speed relative to the speed of rotation of armature wobble about said shaft.

Claim 4

A motion transmitting system, comprising a pair of cooperating gears having confronting frictional surfaces projecting from normally spaced generally parallel planes, electromagnetic means for selectively deflecting sequential points of one of said gears toward and away from the other to produce sequential engagement of said frictional surfaces at instantaneously limited regions of said gears, said gears having mutually different configurations adapted to provide continued digital rotation of said one gear responsive to said deflections, a shaft, and universal joint means coupling one of said gears to said shaft said universal joint means being arranged for wholly free axial and pivotal movement .Iadd.over at least a predetermined range of movement .Iaddend.without radial movement relative to said axis, wherein each of said frictional surfaces comprise teeth, and wherein said frictional contact is achieved by engagement of said teeth, said different configurations being produced by different numbers of teeth on said gears, wherein said cooperating gears are annular, lying along a common axis, the teeth thereof projecting from normally uncurved confronting surfaces thereof; said electromagnetic means including a magnetically permeable armature coupled to said one gear, and electromagnetic actuators disposed in circular array about said common axis, each of said actuators effective when energized to produce an electromagnetic field exerting deflecting forces on said armature and therefore on said one gear coupled thereto, further including a shaft disposed along the axis of said armature, said shaft and said armature arranged for relative rotation, and a further pair of gears, one coupled to said armature and the other coupled to the shaft in cooperating relationship with said one of said further pair of gears, to produce rotation of said shaft in response to deflection and consequent rotation of said armature.

Claim 5

A motion transmitting system, comprising a pair of cooperating gears having confronting frictional surfaces projecting from normally spaced generally parallel planes, electromagnetic means for selectively deflecting sequential points of one of said gears toward and away from the other to produce sequential engagement of said frictional surfaces at instantaneously limited regions of said gears, said gears having mutually different configurations adapted to provide continued digital rotation of said one gear responsive to said deflections, a shaft, and universal joint means coupling one of said gears to said shaft said universal joint means being arranged for wholly free axial and pivotal movement .Iadd.over at least a predetermined range of movement .Iaddend.without radial movement relative to said axis, wherein each of said frictional surfaces comprise teeth, and wherein said frictional contact is achieved by engagement of said teeth, said different configurations being produced by different numbers of teeth on said gears, wherein said cooperating gears are annular, lying along a common axis, the teeth thereof projecting from normally uncurved confronting surfaces thereof; said electromagnetic means including a magnetically permeable armature coupled to said one gear, and electromagnetic actuators disposed in circular array about said common axis, each of said actuators effective when energized to produce an electromagnetic field exerting deflecting forces on said armature and therefore on said one gear coupled thereto, further including a shaft disposed along the axis of said armature, said shaft and said armature arranged for relative rotation, and a further pair of gears, one coupled to said armature and the other coupled to the shaft in cooperating relationship with said one of said further pair of gears, to produce rotation of said shaft in response to deflection and consequent rotation of said armature.

Claim 6

A step motor comprising a shaft, at least one pair of cooperating substantially planar gears having confronting spaced frictional surfaces and having a common axis with said shaft, .Iadd.said gears of said at least one pair having an unequal number of teeth, .Iaddend. a wobble plate supporting one .Iadd.gear .Iaddend.of said .Iadd.at least one .Iaddend.pair of gears, .Iadd.the other gear of said at least one pair of gears being non-rotatively fixed to said shaft, .Iaddend. means pivotally coupling said wobble plate to said shaft for free axial movement therealong .Iadd.over at least a predetermined range of movement .Iaddend.and rotation thereabout while substantially confining said wobble plate against radial motion with respect to said shaft, and means for selectively forcing said wobble plate to pivot on said coupling means to sequentially force portions of said gears in frictional contact against one another for producing relative rotation of said gears .Iadd.and thereby rotation of said shaft. .Iaddend. .[.5. The invention according to claim 4 wherein is further provided means coupling at least one of said pair of gears to said shaft to produce rotation of said shaft..]. .[.6. The invention according to claim 5 wherein said means coupling at least one of said pairs of gears to said shaft includes a further pair of gears, said wobble plate supporting one of said further pair of gears, and means securing the other of said further pair of gears

Claim 7

to said shaft..]. 7. The invention according to claim 4 wherein said wobble plate comprises magnetically permeable material, and wherein said selective forcing means includes electromagnetic means selectively energizable to produce sequential deflection of said wobble plate about

Claim 8

said pivotal coupling means. 8. The invention according to claim 7 wherein said electromagnetic means comprises a pair of stators each including a plurality of core-coil combinations corresponding to switching phases for

Claim 9

said motor, said wobble plate disposed between said stators. 9. The invention according to claim 8 wherein is provided a further pair of cooperating gears coaxial with the first-mentioned pair of gears, said wobble plate supporting one of said further pair of gears on a surface opposite that on which said one of said first-mentioned pair of gears is supported, said pair of stators arranged for selective energization to deflect said wobble plate for frictional contact between diametrically opposed portions of respective gears of said first-mentioned and further

Claim 10

pairs of gears. 10. The invention according to claim 7 wherein said electromagnetic means includes a plurality of coils, each coil having a

Claim 11

magnetically permeable core. 11. The invention according to claim 7 wherein said electromagnetic means comprises a stator having a plurality of core-coil combinations corresponding to switching phases for said motor, said stator having a permanently magnetized portion to provide a magnetic detent for maintaining said wobble plate in the last-deflected

Claim 12

position thereof upon cessation of said selective energization. 12. The invention according to claim 11 wherein said magnetized portion comprises a member fastened to all of the stator cores and permanently magnetized in successive opposite polarity zones at the respective points of fastening of said cores.