Traction machine assembly and elevator

A tractor assembly, comprising:

• a traction sheave, having a traction means fitting surface and a first transmission surface on a peripheral surface thereof;
• a plurality of support wheels, configured to support the traction sheave, and each having a second transmission surface on a peripheral surface thereof;
• and
• support wheel bases, configured to support the support wheels through support shafts,
• wherein the first transmission surface of the traction sheave is in transmitting cooperation with the second transmission surfaces of the plurality of support wheels respectively;
• further comprising an encoder disposed at an end portion of the support shaft and configured to count the number of rotations of the support shaft.

A tractor assembly, comprising:

• a traction sheave, having a traction means fitting surface and a first transmission surface on a peripheral surface thereof;
• a plurality of support wheels, configured to support the traction sheave, and each having a second transmission surface on a peripheral surface thereof;
• and
• support wheel bases, configured to support the support wheels through support shafts,
• wherein the first transmission surface of the traction sheave is in transmitting cooperation with the second transmission surfaces of the plurality of support wheels respectively;
• wherein a linear velocity ratio of the traction sheave to the support wheel is not less than 4:1.