A hydraulic apparatus comprising a casing (1) having arranged therein a hydraulic machine (2), a shaft (4) mounted to rotate relative to the casing (1) by means of a bearing (5), a braking system (3) having a plurality of brake disks (31, 34) configured to prevent the shaft (4) rotating relative to the casing (1) in selective manner, and a control system (6, 7) for controlling said braking disks (31, 34), the hydraulic system including an irrigation system adapted to cool said brake disks (31, 34) by means of a fluid, the irrigation system including a fluid inlet (81) and a fluid outlet (82), the hydraulic system being characterized in that the fluid inlet and outlet (81, 82) of the irrigation system define a fluid flow within the casing in which the braking system (3) is downstream from the hydraulic machine (2).

Disclosed is a brake disc for a railway vehicle including: a disc plate portion with a sliding portion in a surface; and a through hole that penetrates the disc plate portion from a front surface to a back surface of the disc plate portion, in which a bolt for fastening the disc plate portion to a wheel of the railway vehicle is inserted. An inclined surface is formed at an edge of an opening of the through hole at a front side of the disc plate portion, and the inclined surface extends larger in a circumferential direction of the disc plate portion than in a radial direction of the disc plate portion.

A disc brake includes a brake disc made of light metal and a brake pad. The brake disc includes a brake track having formed therein a plurality of depressions which are distributed over a surface of the brake track. The brake disc is formed from a hypereutectic aluminum silicon alloy, which has a silicon content of 13 to 21 wt. % and a maximum content of 0.3 wt. % of copper. The brake pad is configured to act on the brake disc and includes a NAO friction material.

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 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 wet-type multi plate clutch is configured to be used for a transmission in an automobile. A clutch pack is provided with a plurality of drive plates and a plurality of driven plates. The drive plates have single surfaces on which first clutch facings are fixed and opposed surfaces on which annular grooves are formed along entire peripheral lengths. The driven plates have single surfaces on which second clutch facings are fixed and opposed surfaces on which annular grooves are formed along entire peripheral lengths. The sliding surfaces of the drive plates and the driven plates are arranged between the first and second clutch facings, which are axially adjacent with each other.

The present invention relates to a friction disk (2) for a frictionally acting device (78) comprising an annular disk-shaped disk body (18), which has a first edge (30), a second edge (32) facing away from the first edge (30) and with a rotary driving contour (34), and an annular friction surface (26) with a first friction surface edge (36) facing the first edge (30) and a second friction surface edge (38) facing the second edge (32). The first edge (30) and/or the first friction surface edge (36) has a path deviating from a circular path. In addition, the present invention relates to a frictionally acting device (78) with such a friction disk (2).

A brake disc includes an outer circumferential portion including a waveform portion having recessed portions and projecting portions repeatedly formed over an outer circumference, and for the outer circumferential portion to have substantially uniform heat capacity distribution in a circumferential direction and in a radial direction, the outer circumferential portion is formed such that a ratio of a difference in heat capacities among a plurality of circumferential sections in the outer circumferential portion, which are sectioned at an equal angle in the circumferential direction, relative to a heat capacity of each circumferential section is equal to or less than a first predetermined ratio. A ratio of a difference in heat capacities among radial sections in the outer circumferential portion, which are sectioned to have an equal length in the radial direction, relative to a heat capacity of each radial section is equal to or less than a second predetermined ratio.

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 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.