The present disclosure provides a light metal structure-function dual-gradient composite brake disc or brake drum. The light metal structure-function dual-gradient composite brake disc or brake drum is made of a light metal/graded ceramic skeleton composite friction layer bearing friction and wear functions and having function (performance) gradient characteristics and a light metal bearing connection and structure functions and having structure gradient characteristics with the light metal/graded ceramic skeleton composite friction layer by integrated composite casting. Such a dual-gradient brake disc or brake drum can exert the advantages of large thermal capacity, rapid thermal dissipation, and insensitivity to cracks of the light metal, and high hardness, high shear resistance, high elastic modulus, and excellent thermal shock resistance of the graded ceramic skeleton. In addition, the light metal/graded ceramic skeleton composite friction layer can withstand higher temperatures without softening and deformation, such that a temperature during friction braking is more uniform.

A braking band having an annular band body arranged around a rotation axis and made of one of gray cast iron, steel, aluminum or alloys thereof, has at least one braking surface having an activated band body portion for increasing adhesive capacity of at least one protective surface coating placed on the surface of the activated band body portion and having at least one material with elevated resistance to abrasion. The activated band body portion is arranged on the surface of the annular band body to form an outermost layer of the braking band with the at least one protective surface coating and has a rough profile having at least one channel delimited by at least one pair of projections, extending along a path at least partially surrounding the rotation axis and having a channel bottom and a first channel side forming an acute angle with the channel bottom and an opposite second channel side forming an obtuse angle with the channel bottom.

A method of making a brake pad retention plate and a brake pad retention plate is provided. The method includes upsetting a brake pad facing surface on the retention plate to form a first set of rows having a gutter, or a negative feature such as a depression in the primary plane, in the surface of the retention plate and a tooth feature on a first side of the gutter. The surface of the retention plate is upset to form a second set of rows having a gutter and a tooth feature on the second side of the gutter. The second set of rows being a single row. The second set of rows is placed adjacent to or between the first set of rows. A mechanical press is used to deform the tooth to form a base portion and a mezzanine portion extending over a portion of the gutter.

A brake body according to the present disclosure has a coating layer which contains an iron-based amorphous alloy and is formed on a contact surface at which a friction means rubs against the brake body to generate braking force which the brake body is rotated. The coating layer has a low friction coefficient and thus generates less dust during braking. The coating layer also has high corrosion resistance and wear resistance and may thus guarantee high performance and good price competitiveness when applied to a brake base material produced at low cost.

A shaft coupling includes a drive hub that is coupled to a drive shaft to rotate integrally with the drive shaft, a driven hub that is coupled to a driven shaft to rotate integrally with the driven shaft, and a rotation transmission portion that transmits rotation between the drive hub and the driven hub. A dynamic vibration absorber is integrally coupled to a section of at least one of the drive hub and the driven hub. The section is an uninvolved section that is not involved in a torsional stiffness of the whole shaft coupling.

A sintered friction material for brake having a high friction coefficient, with which reduction of the friction coefficient is prevented at high temperature and stable brake performance is maintained. It comprises: a metal matrix of Ni or Ni+Fe (small amount); a solid lubricant (a); and a friction adjusting material (b) including: metal or alloy particles (b1) having an average particle size of 50 μm or more and containing at least one selected from W, Mo, Cr, and FeW; and inorganic particles (b2) containing at least one selected from oxides, nitrides, carbides, and intermetallic compounds. An average particle size d.sub.b1 of b1 and an average particle size d.sub.b2 of b2 satisfy d.sub.b1<d.sub.b2. Dispersing, in the metal matrix, b1 and b2 satisfying particular conditions as the friction adjusting material can produce a geometrical structure (particle structure with a high filling density) suitable for preventing plastic deformation of the sintered friction material.

A method for making a brake disc may include providing a disc brake with a braking band and depositing on the disc a layer of chromium carbide and nickel-chromium in particle form to form a base protective coating. The method may also include depositing on the base protective coating a material in particle form consisting of tungsten carbide, iron, chromium and aluminium to form a surface protective coating made of tungsten carbide, iron, chromium and aluminium. Both protective coatings may be made by High Velocity Oxygen Fuel or High Velocity Air Fuel or Kinetic Metallization techniques.

The present invention provides a sintered metal friction material that has excellent wear resistance, heat resistance even at high load and has a higher friction coefficient while maintaining a friction coefficient and wear resistance that are hard to decrease, and has a reduced content of copper of less than 5 mass %. There is provided a sintered metal friction material characterized in that the sintered metal friction material comprises a sintered material of a friction material composition, the friction material composition comprises matrix metals and a friction modifier, the matrix metals comprise following 20 to 40 mass % of iron powder, 20 to 40 mass % of nickel powder, 0.5 to 10 mass % of zinc powder, 0.5 to 5 mass, of tin powder, 0.5 to 4 mass % of copper powder and 0.5 to 5 mass % of sintering assist powder.

An electromechanical brake comprising mobile induced elements or sectors or frames (2), the number of mobile induced elements (2) or sectors being at least three, where one of the sectors acts faster than the rest, and where one of the sectors acts in a delayed manner with respect to the rest of the sectors in the case of an emergency, said time-delayed actuation being achieved by means of the antiparallel arrangement of a diode (6) on the coil (5) associated with said sector. Smooth and progressive stop is thus achieved in the case of an emergency.

A disc/brake friction torque for railway vehicles consisting of at least one pad comprising at least one friction element and a disc. The friction element is made of a sintered material comprising copper, iron, graphite, 0.02 to 1.5% by weight of molybdenum, 1 to 3% by weight of chrome and a porosity ranging from 20 to 35%; and the disc is made of cast iron comprising 0.05 to 2% by weight of chrome, 0.05 to 2% by weight of molybdenum, 0.1 to 2% by weight of nickel.