| 摘要 |
PROBLEM TO BE SOLVED: To lessen labor required for assembling and disassembling by reducing the length and weight of a center shaft and simplifying the structure of a driving part by supporting the center shaft for driving a cutter disc by a toothed composite cylindrical bearing, and driving the tooth part of a rotary member of the toothed composite cylindrical bearing by a driver. SOLUTION: A cutter disc 2 provided on the front of a shield main body 1 is supported by a boss part 3a formed on the front of a center support type center shaft 3, and the center shaft 3 is supported on a casing 5 fixed to a partition wall 4 of a shield main body 1 through a toothed composite cylindrical bearing G. The toothed composite cylindrical bearing G is so constructed that a projecting part is formed on the inner periphery of a rotary member having a toothed part on the outer periphery thereof, and the rotary member is rotatably supported by plural rollers provided between the projecting part and a recessed part of a fixing member. A tooth part 6a formed on the outer peripheral side of the toothed composite cylindrical bearing G is driven by a pinion mounted on an output shaft of a driver 13 disposed outside the toothed composite cylindrical bearing G. |
