A clutch for use in actuating an aircraft wing tip device is disclosed. The clutch includes first and second friction members each having a frusto-conical friction surface, and a third friction member arranged coaxially with, and between, the first and second friction members. The third friction member has first and second frusto-conical friction surfaces. When the clutch is engaged, the first and second friction surfaces of the third friction member are brought into contact with the friction surfaces of the first and second friction members, respectively. The clutch also includes spacer means operable to separate the friction surfaces from one another when the clutch is in a disengaged state.

A clutch for use in actuating an aircraft wing tip device is disclosed. The clutch includes first and second friction members each having a frusto-conical friction surface, and a third friction member arranged coaxially with, and between, the first and second friction members. The third friction member has first and second frusto-conical friction surfaces. When the clutch is engaged, the first and second friction surfaces of the third friction member are brought into contact with the friction surfaces of the first and second friction members, respectively. The clutch also includes spacer means operable to separate the friction surfaces from one another when the clutch is in a disengaged state.

A speed change device where the plurality of oil holes have a plurality of first oil holes that are closest to the piston in the axial direction and that are disposed side by side in a circumferential direction, and a plurality of different oil holes that are farther from the piston than the plurality of first oil holes in the axial direction, the plurality of oil holes enabling the working oil to be supplied to spaces between the plurality of inner friction plates and the outer friction plates; and a number of the plurality of different oil holes is smaller than a number of the plurality of first oil holes, the plurality of different oil holes being disposed side by side in the circumferential direction at a position that is farther from the piston than the plurality of first oil holes in the axial direction.

A speed change device where the plurality of oil holes have a plurality of first oil holes that are closest to the piston in the axial direction and that are disposed side by side in a circumferential direction, and a plurality of different oil holes that are farther from the piston than the plurality of first oil holes in the axial direction, the plurality of oil holes enabling the working oil to be supplied to spaces between the plurality of inner friction plates and the outer friction plates; and a number of the plurality of different oil holes is smaller than a number of the plurality of first oil holes, the plurality of different oil holes being disposed side by side in the circumferential direction at a position that is farther from the piston than the plurality of first oil holes in the axial direction.

A friction material composition of the present invention includes a fibrous base, a friction regulator, and a binder and has a copper content of 0.5 mass % or less in terms of copper element amount. The friction material composition contains regenerated cellulosic fibers as the fibrous base. In an embodiment of the friction material composition, the regenerated cellulose fiber has a fiber length of 2 mm to 20 mm.

A friction material comprises a base and a porous friction generating layer penetrating into and integral with the base. The base presents a bonding surface. The porous friction generating layer presents a friction generating surface facing opposite the bonding surface of the base. The porous friction generating layer comprises fibers and friction adjusting particles, and about 30 to about 95% of a total surface area of the fibers is in contact with the friction adjusting particles. A curable resin is dispersed throughout the porous friction generating layer and the base.

A friction material comprises a base and a porous friction generating layer penetrating into and integral with the base. The base presents a bonding surface. The porous friction generating layer presents a friction generating surface facing opposite the bonding surface of the base. The porous friction generating layer comprises fibers and friction adjusting particles, and about 30 to about 95% of a total surface area of the fibers is in contact with the friction adjusting particles. A curable resin is dispersed throughout the porous friction generating layer and the base.

A method of making a wet friction material includes providing an outer layer on a base layer to form the wet friction material. The base layer includes a first proportion of fiber material and a first proportion of filler material. The outer layer includes a second proportion of fiber material and a second proportion of filler material. The second fiber proportion is less than the first fiber proportion and the second filler proportion is greater than the first filler proportion. The method further includes forming a modified outer layer by burning off the fiber material of the outer layer.

A method of making a wet friction material includes providing an outer layer on a base layer to form the wet friction material. The base layer includes a proportion of first fiber material and a proportion of first filler material and the outer layer includes a proportion of second fiber material and a proportion of second filler material. The proportion of second fiber material is less than the proportion of first fiber material and the proportion of second filler material is greater than the proportion of first filler material. The method also includes forming a plurality of orifices passing through the outer layer.