A torque-transfer component has splines configured for engaging a corresponding feature of another component, at least a portion of each spline being hardened before a friction-reducing surface coating is applied to the splines. The splines are preferably hardened by nitriding, carburizing, induction hardening, or laser hardening, and the friction-reducing coating preferably comprises diamond-like carbon or tungsten carbide. The coating can be applied using, for example, physical vapor deposition, chemical vapor deposition, chemically assisted physical vapor deposition, autocatalytic electroless deposition, electroplating, or an oxygen fuel gun.

A tolerance ring (200) including a tolerance ring sidewall (404) including a plurality of waves (or bridges) (452) extending at least one of radially inward or outward and having first (416) and second end portions (420) terminating at first (417) and second ends (421), respectively, where the tolerance ring has a first radius of curvature R.sub.i, measured at a point bisecting a circumferential length, L.sub.C, of the tolerance ring sidewall, and a second radius of curvature, R.sub.2, measured along one of the first and second end portions of the tolerance ring sidewall, and wherein at least one of: 1) R.sub.i is greater than R.sub.2, or 2) wherein R.sub.i is negative and R.sub.2 is positive.

A multi-plate clutch transmission includes an arrangement for selectively engaging the clutch by moving the sleeve to cause one or more friction disks on a sleeve connected to a shaft to move into contact with one or more friction disks on a clutch basket connected to a gear driven by another gear and another shaft driven by a prime mover. An arrangement for selectively disengaging the clutch is provided that uses prime mover torque to move the one or more friction disks on the sleeve out of contact with the one or more.friction disks on the clutch basket.

A hysteresis torque generating mechanism includes a first rotor having a slide surface, and a second rotor opposed to the first rotor. The second rotor is configured to slide against the slide surface of the first rotor so as to generate a hysteresis torque. The second rotor includes an initial contact portion and a main friction surface. The initial contact portion is provided to protrude toward the first rotor. The initial contact portion is configured to slide in contact with the slide surface of the first rotor. The main friction surface is configured to slide in contact with the slide surface of the first rotor after abrasion of the initial contact portion.

In a power transmission apparatus, an auxiliary clutch plate different in diameter from driving and driven clutch plates located in a clutch housing. When the driving and driven clutch plates are pressed against each other, the auxiliary clutch plate is pressed to enable transmission of a driving force of an engine to a driving wheel. When a pressing force exerted on the driving and driven clutch plates is released, a pressing force exerted on the auxiliary clutch plate is released to cut off transmission of the driving force of the engine to the driving wheel.

An extendable shaft includes: an inner shaft including a plurality of external teeth; an outer shaft including a plurality of internal teeth that slides relatively to the external teeth; and a resin layer covering the external teeth. The pressure angle of the external teeth is different from the pressure angle of the internal teeth.

Provided is a clutch friction plate and a clutch device configured so that stiction torque can be reduced and each of in gear, shift feeling, and neutral find can be smoothly performed. A clutch device (100) includes clutch friction plates (101). In the clutch friction plate (101), multiple small-piece-shaped friction members (103) are radially bonded to surfaces of a core bar (102) formed in a flat-plate annular shape through an oil groove (105). Each friction member (103) includes an outer side (104a) facing an outer edge portion of the core bar (102) and an inner side (104b) facing an inner edge portion of the core bar (102) and extending parallel to the outer side (104a), and is formed in a rectangular shape. The friction members (103) are bonded onto the core bar (102) in such a direction that the outer side (104a) and the inner side (104b) are inclined at an inclination angle (θ) with respect to a perpendicular line (CL) perpendicular to a line (OL) connecting the center (O1) of the core bar (102) as the center of rotation of the clutch friction plate (101) and the center (O2) of the friction member (103).

A friction plate includes a core plate defining a bore. The core plate includes an interior core surface defining the bore, an exterior core surface radially spaced from the interior core surface, a first clutch face extending between the interior core surface and the exterior core surface and facing a first direction, and a second clutch face extending between the interior core surface and the exterior core surface and facing a second direction opposite the first direction. The friction plate also includes a friction material disposed on at least one of the first and second clutch faces. The core plate also includes a fluid directing portion. A first plate thickness is defined between the first and second clutch faces. A second plate thickness is defined at the fluid directing portion. The second thickness is greater than the first thickness.

In a fixed type constant velocity universal joint, an axial offset amount of a curvature center of each of track grooves of outer and inner joint members is set to 0. The track grooves of the outer and inner joint members are each inclined with respect to an axis line. The track grooves adjacent to each other in a circumferential direction are inclined in opposite directions. The track grooves of the outer and inner joint members that are opposed to each other are inclined with respect to the axis line in opposite directions. A chamfered portion is formed on a track inlet end of each of the track grooves of the outer joint member. When the cage and the inner joint member are inclined with respect to the outer joint member, balls are incorporated into two cage windows at the same time through the chamfered portions.

A sliding spline shaft device of the present invention includes a male spline and a female spline that is fitted to the male spline in an axially slidable manner, and at least one of the splines has a surface processed layer. The surface processed layer includes an undercoat layer, an intermediate layer containing phosphate, and a topcoat layer containing solid lubricant, in this order. The undercoat layer contains iron nitride and/or iron carbide. Thus, the surface of a base material has high hardness. As a result, microscopic deformation of the sliding surface is reduced, and increase in a real contact area is suppressed, whereby stick-slip is prevented.