PURPOSE: To improve lubricity at a contact part between the shaft of a planetary element and the hole part of a retainer, by a method wherein the surfaces of the shaft of the planetary element and the hole part of the retainer for supporting the shaft are formed with a small smooth part and a relatively high-coarse root part.
CONSTITUTION: At a contact part A between an input shaft 1 and a planetary element and a contact part B between a planetary element and outer wheels, a power is transmitted therebetween fundamentally through pure rolling contact. Meanwhile, a engaging part C between the shaft of a planetary shaft and the hole of a retainer 3 for supporting the shaft forms slip contact when no rolling bearing is used in this part. In which case, since a surface therebetween is formed with a relatively low-coarse smooth part and a relatively high-coarse root part, and since a surface where the shaft and the hole part surface make contact with each other forms the low coarse smooth part, protrusions are prevented from interference with each other occurring as in a surface where coarse surfaces make contact with each other, and not so large quantity of wear powder is prevented from production. Further, since the high coarse part of the root part performs a role serving as a fine oil groove, the occurrence of jolting of the two parts is decreased. Namely, even a part having a low clearance keeps an excellent lubricating state.
IMAI RYOJI
SADAMATSU KAZUHISA
