Patent ID: 6544632
Filing Date: 2003-04-08
Classification: F16D,Y10T

Abstract:
A wet friction material having an inside surface and an outside surface, said wet friction material being produced by a paper-making method, comprising:a base material comprising one of a natural pulp fiber and an organic synthetic fiber; a filler comprising one of diatomaceous earth, clay, wollastonite, silica, and carbonate; a friction adjustment agent; and a binder; wherein, prior to setting of the wet frictional material, an excess binder is removed and said friction material is at least one of set at a temperature at which said binder is not completely set, and not directly heated at said inside surface thereof, so that said wet friction material sets while retaining its flexibility even after the setting process, and results in said wet friction material possessing properties such that a ratio A/B is in the range 0.85 to 1.15 where A is a binder concentration from a surface of said wet friction material to a depth of 10 &mgr;m and B is a binder concentration from a depth of 10 &mgr;m to a depth of 100 &mgr;m; and wherein a ratio of an apparent area to a true contact area is more than 20% when measured in an oiled environment.