A new rotary speed converter

A new rotary speed converter without a source of noise and speed irregularity such as gears and belts has been developed. It is transmitted by a friction force working between two ferromagnetic bodies attracting each other by a magnetic force. A spherical or cylindrical idler is put across a gap between two ferromagnetic cylindrical rolls fixed parallel each other. Large attractive forces are produced between the idler and the rolls by magnetic flux passing through their contacts, and generate large friction forces between the idler and the rolls which can transmit a torque. There is almost no noise and slip in this torque transmission mechanism. Therefore, it is suitable to use this system for an application such as a turntable drive of a record player for which noise and slip are fatal. A stepless rotary speed converter is also realizable by combining an idler and two conical rolls placed in parallel and opposite direction. This is very useful as a small size stepless rotary speed converter for which there has been no good method.