Reduction gear with eccentric body

摘要

A reduction gear mechanism applicable for a geared motor used for lifters for business equipment or the like. A trochoid tooth profile internally meshing type planetary reduction gear mechanism is used as the basic reduction gear mechanism. Each of an external gear and an internal gear is formed of a resin having a small rigidity. Each of an output shaft and a bearing supporting the external gear is formed of a metal having a large rigidity. As a result, the reduction mechanism ensures the rigidity and rotational smoothness in usual operation. Moreover, when a torque more than a value required for a mating member to be driven is applied, the external gear and internal gear are deformed, resulting in the increased meshing loss. The reduction mechanism can reduce the efficiency mechanically by the increase in the meshing loss. Even if a reversing load is applied from the output shaft side, the efficiency can be also reduced by the same meshing loss. Namely, there can be obtained a reduction gear provided with an overload preventive function or reverse rotation preventive function without addition of any special mechanism.