A system for operating at least one magnetorheological fluid clutch apparatus may, in a first mode, vary an amount of torque transmission between a driving member and a driven member in the at least one magnetorheological fluid clutch apparatus by actuating at least one coil in the at least one magnetorheological fluid clutch apparatus. In a second mode, the system may cause torque transmission between the driven member and the driving member by setting a desired remanent magnetization level in a magnetic component of the at least one magnetorheological fluid clutch apparatus by actuating the at least one coil in the at least one magnetorheological fluid clutch apparatus.

A brake disc includes a friction ring consisting at least partially of a first material and a brake rotor hat consisting at least partially of a second material that is different from the first material. The friction ring includes a flange formed in the axial direction, wherein the flange is connected to the brake rotor hat by means of at least one connection element. An intermediate piece is provided between the surface of the brake rotor hat in contact with the connection element and the connection element. In this way, a stable mechanical connection is created between the flange of the friction ring and the brake rotor hat.

A magnetorheological fluid clutch apparatus comprises an input(s) having an input shear surface(s). An output(s) is rotatably mounted about the input for rotating about a common axis with the input, the output(s) having output shear surface(s), the input shear surface and the output shear surface separated annular space(s), with magnetorheological fluid, configured to generate a variable amount of torque transmission between the sets of input rotor and output rotor when subjected to a magnetic field. An electromagnet(s) delivers a magnetic field through the magnetorheological fluid, the electromagnet configured to vary the strength of the magnetic field, whereby actuation of the electromagnet results in torque transmission from the input to the output. A member(s) defining at least one of the shear surfaces is made of a low-permeability material.

An electric drum brake for a rotatable element of a passenger motor vehicle. The drum brake has a brake drum and a brake surface which is connected rotationally conjointly to the brake drum, and also an electromagnet arrangement, wherein multiple brake shoes can be pushed against the brake drum by the electromagnet arrangement, and wherein the drum brake has a preloading arrangement which preloads the electromagnet arrangement into a position spaced apart from the brake surface.

A speed-reducing or -increasing apparatus, with first and second crown gears facing one another, with a cam unit that causes the first crown gear to incline with respect to the second crown gear so that the first crown gear meshes with the second crown gear, that causes the first crown gear to precess in such a manner as to move the meshing position, and couples to an input or output shaft. A rolling element is between the cam unit and the first crown gear, and the cam unit includes a first member that couples to the input or output shaft and a second member made of steel and including a rolling element rolling portion where the rolling element rolls, the second member configured to be incapable of rotating relatively to the first member, and at least part of the first member having a lower specific gravity than the second member.

In one aspect, a centering sleeve is disclosed herein that includes a hub defining a central opening extending in an axial direction between a first axial end and a second axial end. At least one of the first axial end or the second axial end includes a plurality of fluid grooves on an axially outer surface. Both the first axial end and the second axial end can include the plurality of fluid grooves.

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.

Brake pads are prepared using a formulation of friction material of the copper-free type (Low-Steel or Organic Non-Asbestos) and at least one friction surface of a brake disc, which is intended to cooperate with the brake pad, is covered with an anti-wear and anti-corrosion coating consisting of a surface layer of chromium carbide particles (Cr3C2) dispersed in a metallic matrix consisting of a NiCr alloy, and coupled to a second layer consisting of selected combinations of metallic materials, chosen from the group consisting of: Cr3C2-high density NiCr, NiAl alloys, FeNiCrMoSiC alloys, metallic nickel, NiCr alloys, and/or any combination of the above.

A disc brake (1) for a utility vehicle includes a brake disc (19), a brake caliper (2) which surrounds the brake disc (19), an application-side brake lining (3), a rim-side brake lining (3a) and an application-side application device (4) which is arranged in the brake caliper (2). The application device (4) has at least one adjustment spindle (5) and a pressure plate (6) that is arranged axially between the adjustment spindle (5) and the application-side brake lining (3). A plain bearing element (7) is arranged between the pressure plate (6) and the adjustment spindle (4).

A process for producing a protective coating on a brake side of a brake disk main element includes using a laser powder build-up welding process. An NbC metal matrix powder or a Cr.sub.3C.sub.2 metal matrix powder is produced by agglomeration and sintering of NbC particles or Cr.sub.3C.sub.2 particles with particles of a metallic matrix composed of a stainless steel. During the laser powder build-up welding process, the NbC metal matrix powder or the Cr.sub.3C.sub.2 metal matrix powder and an aluminum alloy powder is supplied simultaneously to a molten surface region of the brake disk main element which has been melted by a laser.