Patent attributes
A rotational transfer mechanism includes a rotary output shaft, a rotary input shaft positioned inside the rotary output shaft; a circumferentially-uneven-width-space forming portion having a cam surface, to form an accommodation space between the rotary input shaft and the torque transfer cylindrical surface; and a torque transfer member installed in the accommodation space. The cam surface shape is determined by defining a straight line through the rotational axis and the torque-transfer-member axis, defining an imaginary circle having the same shape as the torque transfer member on the straight line at a point where the imaginary-circle axis and the torque-transfer-member axis are symmetrical with respect to the rotational axis; determining a cam-surface determining circle which circumscribes the imaginary circle and the torque transfer member; and defining a circular arc which forms a part of the cam-surface determining circle as the cam surface.
