| 摘要 |
PURPOSE:To reduce the size of an exciting coil and the area of an iron portion, by forming magnetic flux shielding slits tapered such that the sectional area is greater at the opposite side of the friction surface, and thereby increasing the magnetic reluctance of the hollow spaces and reducing the leaked magnetic flux. CONSTITUTION:Tapered slits 16a, 17a are formed in the manner of removing the unnecessary area of the surfaces on the opposite side of friction surfaces. By forming such slits, the area of hollow spaces on the opposite side of the friction surfaces is increased and resistance to the magnetic flux is increased correspondingly. Thus, since the leakage of magnetic flux is reduced, the entire structure of the apparatus can be made compact and the weight is also reduced. At the same time, the manufacturing costs can be lowered. Here, if it is provided that the exciting power of an exciting coil 4 is the same, the width of the slits can be reduced, and the outer diameter of a pulley 6c can be also reduced. |
