SLIDING FRICTION- FREE GEAR

摘要

A sliding friction-free gear has cams of specific profiles, rollers separating cooperating cams that roll over the cams of the gears, thus eliminating the sliding friction between the gears. The rollers are mounted rotatably e.g. in sliders or eccentrics, wherein the sliders, resp. eccentrics, are mounted slidingly, resp. rotatably, in a yoke attached rigidly to a shaft. The rollers are free to execute oscillating motion relative the yoke while rolling over the cam profiles of the cams of the gears. The cooperating members of the gear contact along a line like in conventional evolvent gears, and unlike in the Wildhaber-Novikov's gear (where the momentary contact between teeth of cooperating toothed wheels is pointwise); therefore the gear according to the present invention offers much larger transmission capacity and is much less prone to seizure than known gears.

主权项

1. Sliding friction-less gear comprises at least the following elements: a body; a first shaft supported rotatably in the body for rotation around a first axis of rotation; a second shaft supported rotatably in the body coaxially with the first shaft for rotation around the first axis of rotation; a yoke; and at least one rollers assembly; the body has a first cam secured against, rotation relative the body, the first shaft has a second cam secured against rotation relative the first shaft; the yoke is rigidly connected with the second shaft to form an assembly of the second shaft and the yoke; the assembly of the second shaft and the yoke defines a cylindrical coordinate system (r,φ,z), where rε[0,∞), φε[0,2π), zε(−∞,∞), quiescent relative the assembly of the second shaft and the yoke, and a first Cartesian coordinate system (x,y,z), where x=r cos φ, y=r sin φ, quiescent relative the assembly of the second shaft and the yoke, and the z-axis of the first Cartesian coordinate system coincides with the z-axis of the cylindrical coordinate system; the first shaft defines a second cylindrical coordinate system (r1,φ1,z1), where r1ε[0,∞), φ1ε[0,2π), z1ε(−∞,∞) quiescent relative the first shaft, and a second Cartesian coordinate system (x1,y1,z1), where x1=r1 cos φ1, y1=r1 sin φ1, quiescent relative the first shaft, such that the coordinates (x,y,z) of the first Cartesian coordinate system are related to the coordinates (x1,y1,z1) of the second Cartesian coordinate system by the followings equations: x=x1 cos ψ+y1 sin ψ, y=−x1 sin ψ+y1 cos ψ, z=z1, where ψ is a varying angle of rotation of the second Cartesian coordinate system relative the assembly of the second shaft and the yoke; the body defines a third cylindrical coordinate system (r2,φ2,z2) quiescent relative the body, where r2ε[0,∞), φ21ε[0,2π), z2ε(−∞,∞), and a third Cartesian coordinate system (x2,y2,z2) quiescent relative the body, such that the coordinates (x,y,z) of the first Cartesian coordinate system are related to the coordinates of the third Cartesian coordinate system by the followings equations: x=x2 cos kψ+y2 sin kψ, y=−x2 sin kψ+y2 cos kψ, z=z2, where k is the base transmission ratio of the gear, where the base transmission ratio of the gear is the ratioω2ω1,where ω1 is the rotational speed of the first shaft relative the assembly of the second shaft and the yoke, and ω2 is the rotational speed of the body relative the assembly of the second shaft and the yoke; the at least one rollers assembly consists at least of a first circular roller, the circular profile of which has a first center and a radius ρ1, and a second circular roller the circular profile of which has a second center, and a second radius ρ0; the at least one roller assembly is connected movably with the yoke, such that the first circular roller of the at least one rollers assembly is coaxial with the second circular roller of the at least one rollers assembly, the first circular roller of the at least one rollers assembly is able to revolve relative the yoke around a second axis of rotation, the second circular roller of the at least one rollers assembly is able to revolve relative the yoke around the second axis of rotation, the second circular roller of the at least one rollers assembly is able to revolve relative the first circular roller of the at least one rollers assembly around the second axis of rotation, the first center of the circular profile of the first circular roller and the second center of the circular profile of the second roller both lie on the second axis of rotation, and the at least one rollers assembly is able to move relative the yoke only as a unit so that the distance between the second axis of rotation and the first axis of rotation is able to vary; the at least one rollers assembly is mounted in the body such that the first circular roller of the at least one rollers assembly is tangent to the first cam placed in the body, and the second circular roller of the at least one rollers assembly is tangent to the second cam placed on the first shaft; the first cam placed in the body has a first profile defined in the third cylindrical coordinate system (r2,φ2,z2) by a first continuously differentiable function r2=F(φ2,z2), where for each z2ε(−∞,∞) F(0,z2)=F(2π,z2) andlimϕ→0Fϕ2f(0,z2)=limϕ→2πFϕ2f(2π,z2),such that the first cam has a first number m of lobes and the first number m of valleys; the second cam placed on the first shaft has a second profile defined in the second cylindrical coordinate system (r1,φ1,z1) by a second continuously differentiable function r1=G(φ1,z1), where for each z1ε(−∞,∞) G(0,z1)=G(2π,z1) andlimϕ→0Gϕ1f(0,z1)=limϕ→2πGϕ1f(2π,z1),such that the second cam has a second number n of lobes and the second number n of valleys; the function F(φ2,z2) defining the profile of the first cam placed in the body and the function G(φ2,z2) defining the profile of the second cam placed on the first shaft are such that the first circular roller of the at least one rollers assembly remains in constant contact with the first cam placed in the body, and the second circular roller of the at least one rollers assembly remains in constant contact with the second cam placed on the first shaft, during the revolution of the first shaft relative the body by 360 degrees and during the revolution of the second shaft relative the body by 360 degrees.