| 摘要 |
PROBLEM TO BE SOLVED: To absorb shocks and prevent fatigue resulting from the shocks and extend the life of a reducing gear by transmitting a torque to the reducing gear through a spring or a resilient material and forming a small diameter shaft by use of spring steel. SOLUTION: The rotational speed of a driving part rotating at 3,000 rpm is reduced to drive a rock drill tool at 200 rpm through a reducing gear train. In the train, a torque is transmitted to a ring 3 through a spring 6 or a resilient material 7 by a power transmission structure 5 to engage an internal ring gear 2 of the ring 3 with an external gear 1 eccentrically arranged and rotate the tool through a shaft formed to have a small diameter with spring steel. In this case, the compressive strength of the spring 6 or the resilient material 7 is made to correspond to the torsional strength of the shaft. In this way, the rotary shocks are absorbed by the extending or contracting deformation of the spring 6 or the resilient material 7 to prevent shock fatigue of the speed reducing gear train and elongate its life. |
