摘要 |
A small, inexpensive, comparatively simple differential gear, having reliable revolution difference restricting effects includes a rotary casing and a retainer having a common rotation axis. Torque is transmitted to a groove of a pair of rotary members via rolling elements so the rotary members rotate with the casing. When a revolution difference occurs between the rotary members, rolling elements retained in guide slots of the retainer roll along the grooves of the rotary members so there is reciprocal movement within the range of the guide slots. When a force causing a revolution difference between the rotary members is applied from the side of only one of the rotary members, the resulting reaction force restricts the revolution difference between the pair of rotary members. This is because the rolling elements which come to the following side when the revolution difference exists trail the groove which comes to the leading side when a revolution difference occurs in response to their own movements. Reliable torque-sensitive revolution difference restricting effects are provided without a special mechanism to obtain a revolution difference restricting effect. |