Continuously variable transmission having a double eccentric shaft and a worm gear adjusting mechanism

A continuously variable transmission, comprising:

• a housing arranged about a central axis;
• coaxial first and second rotatable members supported within the housing for independent rotation about the central axis;
• an eccentric shaft operably connected to the first rotatable member for rotation in unison with it, the eccentric shaft having a cylindrical surface formed about an eccentric axis that is parallel to and radially adjustable relative to the central axis;
• at least one orbiter rotatable about the cylindrical surface of the eccentric shaft;
• an anchor ring and a drive ring located in axially spaced locations within the housing, each ring being spaced radially outward from and surrounding the orbiter and having a circular pattern of internal teeth centered about the central axis, the anchor ring being fixed relative to the housing and the drive ring being operably connected to the second rotatable member;
• a plurality of identical rigid anchor vanes operably engaging the orbiter and the anchor ring, the anchor vanes having first ends operably connected to the orbiter for pivotal motion about a first set of vane axes parallel to and angularly spaced about the eccentric axis and second ends having a plurality of teeth complementary to and drivingly meshing with the internal teeth of the anchor ring during a portion of each complete revolution of the eccentric shaft;
• and
• a plurality of identical rigid drive vanes operably engaging the orbiter and the drive ring, the drive vanes having first ends operably connected to the orbiter for pivotal motion about a second set of vane axes parallel to and angularly spaced about the eccentric axis and second ends having a plurality of teeth complementary to and drivingly meshing with the internal teeth of the drive ring during a portion of each complete revolution of the eccentric shaft.

A continuously variable transmission, comprising:

• a housing arranged about a central axis;
• coaxial driving and driven members supported within the housing for independent rotation about the central axis;
• an eccentric shaft operably connected to the driving member, the eccentric shaft having a cylindrical surface formed about an eccentric axis that is parallel to and radially adjustable relative to the central axis;
• at least one orbiter freely rotatable on the cylindrical surface of the eccentric shaft;
• an anchor ring and a drive ring located in axially spaced locations within the housing, each ring being spaced radially outward from and surrounding the orbiter and having a circular pattern of internal teeth centered about the central axis, the anchor ring being fixed relative to the housing and the drive ring being operably connected to the driven member;
• a plurality of identical rigid anchor vanes operably connected between the orbiter and the anchor ring, the anchor vanes having inner ends operably engaging the orbiter for pivotal motion about a first set of vane axes parallel to and angularly spaced about the eccentric axis and outer ends having a plurality of teeth complementary to and meshing with the internal teeth of the anchor ring;
• and
• a plurality of identical rigid drive vanes operably connected between the orbiter and the drive ring, the drive vanes having inner ends operably engaging the orbiter for pivotal motion about a second set of vane axes parallel to and angularly spaced about the eccentric axis and outer ends having a plurality of teeth complementary to and meshing with the internal teeth of the drive ring.

A continuously variable bicycle transmission, comprising:

• a bottom bracket shell arranged about a central axis;
• a crank shaft rotatably mounted through the bottom bracket shell, the crank shaft being centered along the central axis;
• a coaxial output sprocket rotatably supported within the bottom bracket shell and on the crank shaft for independent rotation about the central axis;
• an eccentric shaft surrounding the crank shaft within the bottom bracket shell, the eccentric shaft having a cylindrical surface formed about an eccentric axis that is parallel to the central axis and radially adjustable relative to it;
• an orbiter rotatably supported by the cylindrical surface of the eccentric shaft for free rotation about the eccentric axis;
• an anchor ring and a drive ring located in axially spaced locations within the bottom bracket shell, each ring being spaced radially outward from and surrounding the orbiter and having a circular pattern of internal teeth centered about the central axis, the anchor ring being formed integrally with the bottom bracket shell and the drive ring being formed integrally with the output sprocket;
• a plurality of identical rigid anchor vanes operably connected between the orbiter and the anchor ring, the anchor vanes having inner ends pivotally connected to the orbiter for motion about a first set of vane axes parallel to and angularly spaced about the eccentric axis and outer ends having a plurality of teeth complementary to and meshing with the internal teeth of the anchor ring;
• and
• a plurality of identical rigid drive vanes operably connected between the orbiter and the drive ring, the drive vanes having inner ends pivotally connected to the orbiter for motion about a second set of vane axes parallel to and angularly spaced about the eccentric axis and outer ends having a plurality of teeth complementary to and meshing with the internal teeth of the drive ring.

An adjustable eccentric shaft, comprising:

• first and second eccentric elements independently rotatable relative to one another;
• the first eccentric element being rotatably journalled about a first axis and having an eccentric cylindrical outer surface formed about a first eccentric axis that is parallel to and radially spaced from the first axis;
• the second eccentric element being rotatably mounted about the eccentric cylindrical surface of the first eccentric member and further having an eccentric cylindrical outer surface formed about a second eccentric axis that is parallel to and radially adjustable relative to the first axis by rotation of one eccentric element relative to the other;
• a worm gear fixed to and surrounding the first eccentric element;
• a worm in driving engagement with the worm gear, the worm being rotatably mounted to the second eccentric element for rotational motion in unison with it about the first eccentric axis and for independent rotational motion about a worm shaft axis that is transverse to and radially spaced from the first axis;
• and
• a mechanism operably connected to the worm for selectively rotating the worm about the worm shaft axis.

An adjustable eccentric shaft, comprising:

• a housing centered about a first axis;
• a central drive shaft extending through the housing for rotational motion about the first axis, the central drive shaft having an outer cylindrical surface that is centered about the first axis;
• first and second eccentric shafts axially overlapping one another and the central drive shaft within the housing, the first and second eccentric shafts being independently rotatable relative to one another;
• the first eccentric shaft including a cylindrical inner surface rotatably journalled about the outer cylindrical surface of the central drive shaft and further having an eccentric cylindrical outer surface formed about a first eccentric axis that is parallel to and radially spaced from the first axis;
• the second eccentric shaft including a cylindrical inner surface rotatably journalled about the eccentric cylindrical outer surface of the first eccentric shaft and further having an eccentric cylindrical outer surface formed about a second eccentric axis that is parallel to the first axis and radially adjustable relative to it by rotation of the one eccentric shaft relative to the other;
• a planetary transmission operably connected between the central drive shaft and the first eccentric element;
• a worm gear fixed to and surrounding one of the eccentric shafts;
• a worm in driving engagement with the worm gear, the worm being rotatably mounted to the remaining eccentric shaft for rotational motion in unison with it about the first eccentric axis and for independent rotational motion about a worm shaft axis that is transverse to and radially spaced from the first axis;
• a drive gear positioned at one end of the worm for rotation in unison with the worm about the worm shaft axis;
• an annular shift ring centered about the first axis within the housing, the shift ring being movably supported by spiral threads formed on the housing for axial motion along the first axis in response to rotational motion of the shift ring about the first axis to selectively bring it into meshing engagement with the drive gear;
• and
• a spring operably engaged between the shift ring and the housing for rotationally biasing the shift ring about the first axis to a position disengaged from the drive gear.

An adjustable eccentric shaft, comprising:

• a housing centered about a first axis;
• a central drive shaft extending through the housing for rotational motion about the first axis, the central drive shaft having an outer cylindrical surface that is centered about the first axis;
• first and second eccentric shafts axially overlapping one another and the central drive shaft within the housing, the first and second eccentric shafts being independently rotatable relative to one another;
• the first eccentric shaft including a cylindrical inner surface rotatably journalled about the outer cylindrical surface of the central drive shaft and further having an eccentric cylindrical outer surface formed about a first eccentric axis that is parallel to and radially spaced from the first axis;
• the second eccentric shaft including a cylindrical inner surface rotatably journalled about the eccentric cylindrical outer surface of the first eccentric shaft and further having an eccentric cylindrical outer surface formed about a second eccentric axis that is parallel to the first axis and radially adjustable relative to it by rotation of the one eccentric shaft relative to the other;
• a planetary transmission operably connected between the central drive shaft and the first eccentric element;
• a worm gear fixed to and surrounding one of the eccentric shafts;
• a worm in driving engagement with the worm gear, the worm being rotatably mounted to the remaining eccentric shaft for rotational motion in unison with it about the first eccentric axis and for independent rotational motion about a worm shaft axis that is transverse to and radially spaced from the first axis;
• first and second opposed drive gears positioned respectively at opposite ends of the worm for rotation in unison with the worm about the worm shaft axis;
• a first annular shift ring centered about the first axis within the housing, the first shift ring being movably supported by spiral threads formed on the housing for axial motion along the first axis in response to rotational motion of the shift ring about the first axis to selectively bring it into meshing engagement with the first drive gear;
• a second annular shift ring centered about the first axis within the housing, the second shift ring being movably supported by the housing for axial motion along the first axis to selectively bring it into meshing engagement with the second drive gear;
• a first spring operably engaged between the shift ring and the housing, the first spring pivotally biasing the first shift ring to a position disengaged from the first drive gear;
• and
• a second spring operably engaged between the shift ring and the housing, the second spring pivotally biasing the second shift ring to a position disengaged from the second drive gear.