Planetary drive

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein said flexible planetary wheel is surrounded by a thin-walled, flexible ring for taking up tensile stresses.

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein said hollow wheel is supported by an elastic element on a solid ring.

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein said planetary wheel is flexible both radially and circumferentially;
• said planetary wheel being sufficiently flexible in the circumferential direction that the teeth of the planetary wheel can shift circumferentially to accommodate varying effective tooth distributions in the engagement regions.

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein said planetary wheel is flexible both radially and circumferentially and comprises circumferentially alternating, radially inwardly and outwardly projecting tooth portions connected to each other by web-form regions having a circumferential thickness, and each tooth portion has a radial height which is greater than the circumferential thickness of said web-form regions.

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein the teeth of said hollow wheel are constructed with substantially flat tooth flanks and points of the teeth of said hollow wheel are flattened to increase the internal diameter of said hollow wheel, the inner diameter of said hollow wheel substantially corresponding to the outer diameter of peaks of the external teeth of said planetary wheel at a point of maximum engagement between internal teeth of said planetary wheel and teeth of said sun wheel, whereby the peaks of the external teeth of said planetary wheel are disengaged from the teeth of said hollow wheel at said point of maximum engagement between said planetary wheel and said sun wheel, and the amount of deformation of said planetary wheel required to engage with and disengage from said hollow wheel is decreased.

A planetary drive comprising an externally toothed sun wheel;

• a toothed hollow wheel coaxial to said sun wheel;
• a radially flexible planetary wheel having internal teeth and external teeth and arranged at least partially in an annular gap between said hollow wheel and said sun wheel;
• a rotatably mounted cam element for radially deforming said planetary wheel in such a way that external teeth on said planetary wheel engage teeth on said hollow wheel and internal teeth on said planetary wheel engage teeth on said sun wheel in a plurality of engagement zones distributed around the circumference of said planetary wheel;
• and a roller bearing interposed between said cam element and said planetary wheel, wherein the teeth of said sun wheel are constructed with substantially flat tooth flanks and and peaks of teeth of said sun wheel are flattened to decrease the outer diameter of said sun wheel, the outer diameter of said sun wheel substantially corresponding to the inner diameter of peaks of the internal teeth of said planetary wheel at a point of maximum engagement between said planetary wheel and said hollow wheel, whereby the internal teeth of said planetary wheel are disengaged from the teeth of said sun wheel at said point of maximum engagement between said planetary wheel and said hollow wheel, and the amount of deformation of said planetary wheel required to engage with and disengage from said sun wheel is decreased.