ROTATION TRANSMISSION DEVICE

摘要

PROBLEM TO BE SOLVED: To suppress vibration transmission between a driving shaft and a driven shaft and enable precise processing in a rotation transmission device which adopts a viscous coupling used for a headstock of a machine tool by forming circular grooves opposedly to each other on first and second plates fixed to the ends of the driving shaft and the driven shaft. SOLUTION: A main shaft (driven shaft) 2 on a headstock 15 of a built-in motor 10 is rotatably journalled around the same axis as a driving shaft 1. A viscous coupling 3 which transmits the rotation of the driving shaft 1 to the main shaft 2 has a first plate 4 fixed to an end surface of the driving shaft 1 and a second plate 6 rotatably joused inside the first plate 4. A first circular groove 8 is formed inside the first plate 4 on the side of an opening 7, while a second circular groove 9 is formed on the second plate 6 opposedly to the first circular groove 8. Viscous oil 19 is prevented from leaking from the opening 7 to the outside by means of the circular grooves 8, 9.