PURPOSE: To form-roll long columnar bodies having different dimensions in a wide range by deciding the eccentric quantity of the center of a ring roll caliber with respect to the axial center of a gear by the combination of the key grooves of the gear and a cylinder at the contacting surface of them.
CONSTITUTION: An inner hole 2 is eccentrically provided to a gear 1, and a cylinder 3 is fitted freely rotatably to the hole 2; an inner hole 4 is also provided eccentrically to the cylinder 3, and a ring roll 5 is freely rotatably fitted to the hole 4. A pipe 6 is form-rolled between the inner peripheral surface of roll 5 and a mandrel 7. The distance KN between the axial center K of gear 1 and the center N of inner hole 2 deviated from the center K, is denoted by r1; an angle between the r1 and an axisymmetric axis Y, -Y is denoted by θ1. Further, the center distance between the inner and outer circles of the cylinder 3 inscribed in the hole 2 is denoted by r2, and an angle between the axisymmetric axis LN of cylinder 3 and the axis Y, -Y is denoted by θ2. The eccentric quantity of the center L of ring caliber, to be deviated at that time, with respect to the axial center K of gear 1, is changed by changing the (θ2-θ1), and the (θ2-θ1) is properly selected by inserting a key 9 into the key groove 8.
KAWANAMI TAKAO
JP38005957A |