A wet friction disc includes a lubrication groove and a plurality of lands defined by the lubrication groove. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and has a predetermined groove width in a radial direction, and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least some of the circumferential groove portions have an arc shape such that an end in the circumferential direction is located adjacent to one of the lands in the circumferential direction and that the groove width is entirely contained within a range in the radial direction spanned by that land.

A brake disk or drum has at least one working surface which opposes a braking member such as a brake pad or shoe. A plurality of spaced, raised island formations are provided across the working surface, with channels extending between the island formations. Each raised island formation has an outer surface which contacts a brake pad or brake shoe during braking.

A disk rotor of a vehicle brake with improved efficiency in cooling the disk rotor by a synergy effect that comes from ensuring velocity of airflow flowing between cooling fins, ensuring surface areas of the cooling fins, and generating turbulent flow by second fins. A plurality of cooling fins each extending radially from an inner peripheral edge to an outer peripheral edge of a disk rotor are provided inside the disk rotor at intervals in the circumferential direction. Each of the plurality of the cooling fins includes a radial fin extending radially and a second fin spaced apart from the radial fin in the radial direction.

A controller controls switching between a braked state in which a movable meshing part 7 comes close to and meshes with a motor meshing part 6 and a brake released state in which the movable meshing part 7 is separated from the motor meshing part 6.

A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

A brake disk or drum has at least one working surface which opposes a braking member such as a brake pad or shoe. A plurality of spaced, raised island formations are provided across the working surface, with channels extending between the island formations. Each raised island formation has an outer surface which contacts a brake pad or brake shoe during braking.

A brake disc for a railway vehicle includes: a disc plate portion that has a sliding portion of a front face; a plurality of radial fins that are provided on the rear face of a disc plate portion, and that have a shape that extends in the radial direction of the disc plate portion; and a circumferential rib that is provided between each pair of adjacent radial fins, and that has a shape that extends in the circumferential direction of the disc plate portion. A flow path for air is formed between the pair of radial fins, and the flow path for air is narrowed by the circumferential rib. On the circumferential rib, a gradual slope for suppressing fluctuations in an airflow that passes between the pair of radial fins is provided from a base part to a top part.

A brake disk unit includes a rotating member, a brake disk, and a control member. The brake disk includes a disk main body, fins, and convex portions and/or concave portions. The control member includes a support portion and a projecting portion. At least a part of the projecting portion is arranged between fins that are adjacent in the circumferential direction of the brake disk. A gap is formed between the projecting portion and the brake disk. On the surface of the brake disk, the convex portions and/or the concave portions are provided further on the outer side in the radial direction of the brake disk than a minimum opening portion of the gap.

Various embodiments of aircraft brake assembly structures are provided for achieving noise reduction during braking activity. In certain embodiments of the invention, the actual application of force to the pressure plate is regulated such that a different number of actuator pistons are used during low-energy stops than during high-energy stops. In other embodiments of the invention, the pressure plate or endplate is augmented as to surface area in some instances and as to a taper angle in others, again to achieve a desired increase in effective pressure application during low-energy stops. In other embodiments of the invention, the stator and/or rotor disks are characterized by slots to break up the propagation of noise waves.

A method of manufacturing a disc brake rotor comprises preparing at least one elongated plate having a first end and a second end opposite to the first end in a longitudinal direction of the at least one elongated plate. The method comprises bending the at least one elongated plate in an arc shape.