Traction drive transmission

A planetary traction drive transmission that is organized about a center axis (X), said transmission comprising:

• a center shaft having first and second inner raceways that are presented outwardly away from the axis (X), the first inner raceway being tapered and lying in a conical envelope having its apex at a point (S) along the axis (X), the second inner raceway being tapered and lying in a conical envelope having its apex at another point (T) along the axis (X), the conical envelopes for the first and second inner raceways intersecting at a point (A) which lies between the point (S) and the point (T);
• an outer ring having first and second outer raceways which are presented inwardly toward the axis (X), with the first outer raceway surrounding the first inner raceway and the second outer raceway surrounding the second inner raceway, the first outer raceway being tapered and lying in a conical envelope that has its apex at the point (S), the second outer raceway being tapered and lying in an envelope having its apex at the point (T), the first and second outer raceways intersecting at yet another point (C) that lies between the point (S) and the point (T);
• first rollers located between the first inner and outer raceways, the tapered peripheral surfaces of the first rollers lying in conical envelopes having axes (U) and their apexes at the point (S);
• each first roller at its large end having a back face that is at least in part convex and conical;
• second rollers located between the second inner and outer raceways and having tapered peripheral surfaces along which they are in line contact with the second inner and outer raceways, the tapered peripheral surfaces of the second rollers lying on conical envelopes having axes (V) and their apexes at the point (T);
• each second roller at its large end having a back face that is at least in part convex and conical;
• the first and second rollers being arranged in pairs with the back faces of the rollers of each pair being presented toward each other and the convex and conical portions of those back faces contacting each other along a straight line that connects the point (A) and the point (C), the axes (U) and (V) for each pair of first and second rollers intersecting at yet another point (B) that lies along the straight line connecting point (A) and the point (C);
• and a roller carrier having axles that extend into the first and second rollers so that the first and second rollers revolve about the axles of the carrier.

A planetary traction drive transmission that is organized around a center axis, said transmission comprising:

• a center shaft having first and second inner raceways that are presented away from the center axis;
• an outer ring having first and second outer raceways presented toward the center axis, with the first outer raceway generally surrounding the first inner raceway and the second outer raceway generally surrounding the second inner raceway;
• first rollers located between and having peripheral surfaces which contact the first inner and outer raceways and second rollers located between and having peripheral surfaces which contact the second inner and outer raceways, the first and second rollers also having back faces and being arranged in pairs, with each pair including one of the first rollers and one of the second rollers, the rollers of each pair having their back faces presented toward and contacting each other;
• and a roller carrier coupled with the first and second rollers and having axles which project into the first and second rollers so that the first and second rollers revolve about the axles, the first and second rollers of each pair revolving about only one of the axles;
• and wherein substantially pure rolling contact characterized by the absence of spinning exists between the peripheral surfaces of the first rollers and the first inner and outer raceways and between the peripheral surfaces of the second rollers and the second inner and outer raceways and between the back faces of the first and second rollers of each pair, when the first and second rollers of each pair revolve between the center shaft and the outer ring.

A planetary traction drive transmission that is organized about a center axis (X), said transmission comprising:

• a center shaft having first and second inner raceways that are presented outwardly away from the axis (X), the first inner raceway being tapered and lying in a conical envelope having its apex at a point (S) along the axis (X), the second inner raceway being tapered and lying in a conical envelope having its apex at another point (T) along the axis X, the conical envelopes for the first and second inner raceways intersecting at still another point (A) which lies between the point (S) and the point (T), an outer ring having first and second outer raceways which are presented inwardly toward the axis (X), with the first outer raceway surrounding the first inner raceway and the second outer raceway surrounding the second inner raceway, the first outer raceway being tapered and lying in a conical envelope that has its apex at the point (S), the second outer raceway being tapered and lying in an envelope having its apex at the point (T), the first and second outer raceways intersecting at yet another point (C) that lies between the point (S) and the point (T);
• first rollers located between the first inner and outer raceways and having tapered peripheral surfaces along which they are in line contact with the first inner and outer raceways and having tapered peripheral surfaces along which they are in line contact with the first inner and outer raceways, the tapered peripheral surfaces of the first rollers lying in conical envelopes having axes (U) and their apexes at the point (S), each first roller at its large end having a back face that is at least in part convex and conical;
• second rollers located between the inner and outer second raceways and having tapered peripheral surfaces along which they are in line contact with the second inner and outer raceways, the tapered peripheral surfaces of the second rollers lying in conical envelopes having axes (V) and their apexes at the point (T), each second roller at its large end having a back face that is at least in part convex and conical;
• the first and second rollers being arranged in pairs with the back faces of the rollers of each pair being presented toward each other and the convex and conical portions of those back faces contacting each other along a straight line that connects the point (A) and the point (C), the axes (U) and (V) for each pair of first and second rollers intersecting yet another point (B) that lies along the straight line connecting the point (A) and the point (C), and a roller carrier having axles which are straight and extend into the first and second rollers so that the first and second rollers revolve about the axles of the carrier, there being a separate axle for each pair of first and second rollers so that the first and second rollers of each pair share one of the axles.