A brake element for a transportation vehicle, having a base body that is planar at least in some regions, to the planar sides of which at least two build-up layers are applied in each case at least in some regions. The build-up layers form a surface which, in the mounted state of the brake element on the transportation vehicle, serves as a friction surface for a brake pad. There is a bonding zone in which both a material of the base body and a material of a build-up layer adjacent to the base body are present, wherein the bonding zone has a thickness perpendicular to an areal extent of a planar side that is less than 10 μm.

A fine blanking device and method for forming a friction plate with friction material layers. The fine blanking device includes an upper die, a lower die, a guide mechanism, a punch and a counter punch. Upper and lower blank holders are respectively provided at outer circumferences of the punch and the counter punch. The upper and lower blank holders are respectively provided with a buffer mechanism. Friction material powders are sintered on both sides of the base sheet. The friction material layers are trimmed and planished by hot pressing. The base sheet with the friction material layers is fixed by the upper blank holder and the lower blank holder. A tooth profile with an absolute shear fractural surface is formed. The fixing indentation of the V-shaped structure of the friction material layers is cut off for obtaining a finished friction plate product with the friction material layers.

A brake disc for a friction brake of a transportation vehicle includes a friction portion having at least one friction surface and a fastening portion for fastening to the transportation vehicle, wherein the friction portion and the fastening portion are formed on a base body of gray cast iron or steel, and an anti-wear layer is applied to the friction portion as the friction surface by laser deposition welding. The anti-wear layer on the base body is continued beyond the friction surface into a region that is angled relative to the friction surface, and ends in that region, and is applied in the angled region of the base body with full coverage and without any gaps to the base body. Surface portions outside of the friction surface are provided with an anti-corrosion layer which overlaps the anti-wear layer in the angled region.

The wet friction member 1 of the invention includes a core plate 2 formed in a flat ring shape, a friction part 3 arranged in a ring shape. The friction part 3 has segment pieces including rectangular shaped G.sub.1 to G.sub.4: G.sub.1 in which a lower right corner of rectangular piece is notched; G.sub.2 in which an upper left corner of rectangular piece is notched; G.sub.3 in which an upper right corner of rectangular piece is notched; G.sub.4 in which a lower left corner of rectangular piece is notched. The friction part 3 has arrangements T.sub.1 and T.sub.2: T.sub.1 in which G.sub.1 and G.sub.2 are arranged in a manner a right side of G.sub.1 and a left side of G.sub.2 face each other; T.sub.2 in which G.sub.3 and G.sub.4 are arranged in a manner a right side of the G.sub.3 and a left side of G.sub.4 face each other.

A brake rotor assembly can include a structural part having a receiving surface and at least one friction surface parts having a contact surface. The friction surface part can be fixably attached to the receiving surface of the structural part such that the contact surface faces away from the receiving surface of the structural surface to form at least part of an annular braking surface arranged concentrically around an axis of rotation of the structural part.

A fine blanking device and method for forming a friction plate with friction material layers. The fine blanking device includes an upper die, a lower die, a guide mechanism, a punch and a counter punch. Upper and lower blank holders are respectively provided at outer circumferences of the punch and the counter punch. The upper and lower blank holders are respectively provided with a buffer mechanism. Friction material powders are sintered on both sides of the base sheet. The friction material layers are trimmed and planished by hot pressing. The base sheet with the friction material layers is fixed by the upper blank holder and the lower blank holder. A tooth profile with an absolute shear fractural surface is formed. The fixing indentation of the V-shaped structure of the friction material layers is cut off for obtaining a finished friction plate product with the friction material layers.

A brake disc used for brake systems of motor vehicles, rail vehicles and aircrafts and the brake disc includes a brake disc body, wherein the brake disc body is an aluminum alloy brake disc body, the two working surfaces of the aluminum alloy brake disc body are respectively attached with a wear-resistant layer, the wear-resistant layers are wear-resistant layers made of ceramic high-temperature resistant metal matrix composite (MMC) reinforced materials, and the wear-resistant layers made of ceramic high-temperature resistant MMC reinforced materials metallurgically bond with the aluminum alloy brake disc body through a squeeze casting technique.

A brake rotor assembly can include a structural part having a receiving surface and at least one friction surface parts having a contact surface. The friction surface part can be fixably attached to the receiving surface of the structural part such that the contact surface faces away from the receiving surface of the structural surface to form at least part of an annular braking surface arranged concentrically around an axis of rotation of the structural part.

The wet friction member 1 of the invention includes a core plate 2 formed in a flat ring shape, a friction part 3 arranged in a ring shape. The friction part 3 has segment pieces including rectangular shaped G.sub.1 to G.sub.4: G.sub.1 in which a lower right corner of rectangular piece is notched; G.sub.2 in which an upper left corner of rectangular piece is notched; G.sub.3 in which an upper right corner of rectangular piece is notched; G.sub.4 in which a lower left corner of rectangular piece is notched. The friction part 3 has arrangements T.sub.1 and T.sub.2: T.sub.1 in which G.sub.1 and G.sub.2 are arranged in a manner a right side of G.sub.1 and a left side of G.sub.2 face each other; T.sub.2 in which G.sub.3 and G.sub.4 are arranged in a manner a right side of the G.sub.3 and a left side of G.sub.4 face each other.

A friction engagement device of an automatic transmission is provided, which includes a rotational member comprised of at least one of a drum member and a hub member including a spline part engaged with a friction plate to be movable in axial directions of the automatic transmission, and a drive force transmitting part for exchanging a drive force with another rotational element. The drive force transmitting part of the rotational member is made of a ferrous metal. A part of the rotational member other than the drive force transmitting part is made of a clad material containing a first material that is easily joined to the ferrous metal and a second material that is less easily joined to the ferrous metal compared to the first material and weighs less than the ferrous metal.