A thermo-set resin composition comprising a Quebracho wood tannin extract, a furfuryl alcohol, a neoprene compound, a dimethicone, polyethylene glycol, abrasive particles, and a glycerol phosphate acidic ester and/or graphite. Further, a method of preparing the thermo-set resin composition including mixing Quebracho wood tannin extract with a furfuryl alcohol to form a primary mixture, adding additives and abrasive particles to the primary mixture, and reacting the primary mixture by adding a catalyst. The thermo-set resin composition is molded into a shape under heat and pressure to a Brinell hardness 8.5 daN/mm.sup.2 and 48 daN/mm.sup.2 and can be incorporated into a friction pad of a brake pad.

A friction material composition includes a binder, organic filler, inorganic filler and fiber reinforcement, and does not contain copper or contains copper in an amount of 0.5 mass % or less. The inorganic filler is one or more selected from y alumina having an average particle size of 10 nm to 50 μm, dolomite having an average particle size of 1 to 20 μm, calcium carbonate having an average particle size of 1 to 20 μm, magnesium carbonate having an average particle size of 1 to 20 μm, manganese dioxide having an average particle size of 1 to 20 μm, zinc oxide having an average particle size of 10 nm to 1 μm, magnetite having an average particle size of 1.0 μm or less, cerium oxide having an average particle size of 0.5 to 5 μm, and zirconia having an average particle size of 5 to 50 nm.

A friction material composition that does not contain copper, which has a high environmental load, or containing copper in such small amount as to be not more than 0.5 mass % and that enables decrease in brake vibration in braking at high temperatures when used in a friction material such that for an automobile disc brake pad, is provided. A friction material obtained by molding the friction material composition is also provided. The friction material composition contains a binder, an organic filler, an inorganic filler, and a fibrous base material, and the friction material composition contains no copper as an element or contains not more than 0.5 mass % of copper, and also contains 2 to 5 mass % of steel fibers that have fiber lengths of 2500 μm or less.

In relation to the NAO friction material free of copper component, this invention is to provide the friction material that prevents the occurrence of metal catch while securing sufficient wear resistance. In the friction material manufactured by forming the NAO friction material composition which is free of copper component, the above-described friction material composition does not contain metal simple substance or alloy and contains, as the lubricant, metal sulfide having 600 centigrade or higher decomposition temperature to be decomposed into metal and sulfur, 2.0-5.0 weight % of graphite and a zirconium silicate as an abrasive material. Here, the metal sulfide is not a molybdenum disulfide or a tungsten disulfide. Especially, the content of the metal sulfide is preferably 0.5-2.0 weight % relative to the total amount of the friction material composition.

The brake pad 10 includes a friction material 12 provided on the side of the disc 200 and a back plate 11 bonded to the friction material on the opposite side of the disc 200. A thickness of a peripheral region of the back plate on the side of a center of the disc is larger than a thickness of a peripheral region of the back plate on the side of an outer circumference of the disc. In the case where a minimum value of the thickness of the peripheral region of the back plate on the side of the center of the disc is defined as “h.sub.2 [mm]” and a maximum value of the thickness of the peripheral region of the back plate 11 on the side of the outer circumference of the disc is defined as “h.sub.1 [mm]”, h.sub.1 and h.sub.2 satisfy a relationship of “h.sub.2−h.sub.1<3”.

Using a friction material composition comprising: a fiber; a friction adjusting material; a binding material; and an uncrosslinked rubber being solid at normal temperature (25° C.), a friction material is obtained, wherein an ambient compressibility in a piston-pressing direction is 2% or less at normal temperature (25° C.) and at 4 MPa, and a tan δ value in a sliding direction at −20° C. to 50° C. is 0.05 or larger. Thereby, a friction material which has high damping properties and acceptable brake noise, which can prevent a decrease in responsiveness when brakes are applied, and prevent a decrease in the feeling of effectiveness associated therewith, and which can suppress a decrease in the fuel efficiency and an increase in abrasion caused by the dragging occurring when the friction material is brought into contact with a brake rotor; and a method for producing the friction material, can be provided.

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.

[Object] To provide the underlayer composition for the disc brake pad, which may be applicable to the manufacturing process of softening the rubber by heating even if the uncrosslinked fluororubber in the underlayer composition and the disc brake pad with an excellent brake noise suppression effect.

[Means to Resolve] To use the underlayer composition containing 5-15 weight % of the uncrosslinked fluororubber relative to the entire amount of the underlayer composition, 4-8 weight % of the phenol-based resin as the binder relative to the entire amount of the underlayer composition, and 0.3-2 weight % of the hexamethylenetetramine as the curing agent for the phenol-based resin relative to the entire amount of the underlayer composition.

An actuator includes a first ball-ramp plate, a second ball-ramp plate, and a plurality of balls. The first ball-ramp plate is formed of compressed powdered metal with ramps having a higher density than at least part of a remainder of the ball-ramp component. A method of manufacturing the actuator includes compacting a metal powder to form a blank of the first ball-ramp plate including an annular body disposed about an axis and a plurality of ramps fixedly coupled to the annular body and spaced circumferentially about the axis, and locally densifying the ramps of the blank by applying force to a ramped surface of each ramp.

An object of the present invention is to provide a friction material for disc brake that can prevent occurrence of a rust adhesion phenomenon and has stable friction characteristics even after being left in a low temperature and high humidity environment. The present invention relates to a friction material for disc brake, containing: a wax containing, as a main component, an ester of a higher fatty acid and a higher alcohol.