| 摘要 |
A wet type friction clutch and an electromagnetic clutch is disclosed wherein a pilot clutch 61 is disposed in a magnetic flux path 95 of an electromagnet 57 and is kept between an armature 71 and the electromagnet 57. Upon excitation of the electromagnet 57, the armature 57 is retracted to allow the pilot clutch 61 to be coupled. The pilot clutch 61 includes a plurality of clutch plates 87, 89 which are interleaved with respect to one another for sliding movements. Adjacent clutch plates 87, 87A, 87B, 89, 89A, 89B, 89C, 89D, 89E, 89F are formed with oil guide passageways 86, 96, 98, 106, 108, 110, 114 to create a hydrodynamic pressure effect to allow the clutch plates to be separated with a limited drag torque. Further, the clutch plate has magnetic flux path forming portions 89b, 89c, at inner and outer peripheral sides, between which through-bores 112 are formed to allow bridge portions 120 to be intervened between the through-bores, with each of the bridge portions being configured such that opposing walls of the bridge portions of adjacent clutch plates have reduced contact surface areas to eliminate a leakage of a magnetic flux. |
