| 摘要 |
<p>To be able to promote discharge of lubricating oil in a disengaged state while maintaining a large lining area to such an extent that it does not affect torque transmission capacity, heat resistance, and peeling resistance thereby to obtain an excellent effect to reduce a drag torque in a wide range of relative rotation speeds. In a segment friction material 1A as a wet friction material, drag torque reducing grooves 5A are provided only on top surfaces of part of segment pieces 3A among thirty pieces of segment pieces 3, 3A. A series of drag torque reducing grooves 5A extend over five segment pieces 3A along a direction almost at right angles to a straight line connecting a center point 5Aa thereof and a center O of a circumference. The series of drag torque reducing grooves 5A are provided at three places on the circumference. Thereby, discharge of ATF is promoted without reducing a lining area and an oil film is formed on the top surface of the segment piece 3A. Thus, a great effect to reduce a drag torque was obtained in a wide range of relative rotation speeds (500 rpm to 5000 rpm).</p> |
