TORQUE CONTROL DEVICE AND VALVE TIMING CONTROL APPARATUS

摘要

A torque control device includes a seal structure sealing a clearance between a hollow object and a rotation shaft. The seal structure includes a particle seal, a liquid seal, an intermediate fluid which fills a middle chamber defined between the particle seal and the liquid seal, and a coating film having a hardness higher than that of magnetic particle. The coating film is arranged to at least at a seal perimeter part of the rotation shaft, and a seal gap is defined between the particle seal and the seal perimeter part.

主权项

1. A torque control device comprising:
a hollow object in which a fluid chamber is defined; a functional fluid in which a magnetic particle is suspended in a base liquid, the fluid chamber being filled with the functional fluid; a viscosity control portion variably controlling a viscosity of the functional fluid by causing a magnetic flux to pass through the functional fluid in the fluid chamber; an adjustment rotor having a rotation shaft which passes through the hollow object, the adjustment rotor contacting the functional fluid in the fluid chamber to control a torque given to the rotation shaft according to the viscosity of the functional fluid; and a seal structure sealing a clearance between the hollow object and the rotation shaft, wherein the seal structure including
a particle seal surrounding a perimeter part of the rotation shaft and held by the hollow object, a seal gap being defined between the particle seal and the rotation shaft and communicating with the fluid chamber to regulate the magnetic particle from flowing out of the hollow object,a liquid seal held by the hollow object at an exterior side of the particle seal, the liquid seal being liquid-tightly in contact with the perimeter part of the rotation shaft to seal a clearance spaced from the rotation shaft,an intermediate fluid which fills a middle chamber defined between the particle seal and the liquid seal, anda coating film having a hardness higher than that of the magnetic particle, the coating film being arranged to the perimeter part of the rotation shaft, at least at a seal perimeter part made of metal, the seal gap being defined between the particle seal and the seal perimeter part.