Industrie Pirelli S.p.a.

Pirelli Trasmissioni Industriali S.p.a.

Pirelli Transmissioni Industriali S.p.a.

Edoardo Robecchi

Giorgio Tangorra

Renato Dell'Orto

Vincenzo Macchiarulo

Lino Magnabosco

Alberto Ruffini

An elastic driving belt stretched between two pulleys of fixed distance between centers and having a predetermined starting tensioning, undergoes a permanent elongation such that the residual elastic elongation has a percent value included between the detectable percent contraction values along the inner edge of the belt itself when the latter is respectively wound according to two predetermined bending lines, the residual elastic elongation being detected by measuring the residual tensioning value on the belt when the permanent elongation has occurred, and reading the elongation value corresponding to the residual tensioning value on a load-elongation graph relating to the belt.

Elastic driving belt and process for identifying and detecting residual

A tensioning device is provided for a flexible belt wound around the pulleys of a drive mechanism. The tensioning device includes an elastic biasing element and a damping mechanism. The biasing element applies a force on the belt in a predetermined direction to oppose belt slackenings. The damping mechanism dampens movements of the belt. The biasing element and the damping mechanism constitute a single unit wherein both exert on the belt forces which act on the belt at the same time in a predetermined direction to maintain a predetermined tensioning. The biasing element acts independently of the damping mechanism in the presence of considerable slackenings of the belt and functions as part of the damping mechanism to dampen thrusts of the belt acting on the device in the direction opposite to the predetermined direction. A connection unit connects the damping mechanism to the biasing element. This connection unit is an elastic system which applies a reaction force according to the predetermined direction in which the biasing element acts on the belt.

Tensioning device for flexible driving belts

An elastically extensible flexible belt is provided which comprises an annular body of elastomeric material in which is embedded a plurality of elongated elements arranged along a surface corresponding to the position of the neutral axis of the belt. The belt is characterized in that each elongated element, at 1/10 of its ultimate tensile stress, has an elongation value able to balance a shrinkage value of the innermost surface of the belt, ranging between two limit values .epsilon..sub.1 .epsilon..sub.2 corresponding to the bending of the belt according to two pre-established curvatures. The first curvature is represented by a circumference whose radius r.sub.1 is equal to 60% of the radius R of the circumferential development of the annular body in correspondence of the elongated elements and the second curvature is represented by a circumference whose radius r.sub.2 corresponds to 35% of the radius R of the circumferential development of the annular body.

Flexible belt and relative driving system

A flexible belt, made of an elastomeric material, comprising an annular body, delimited by two base surfaces and by two lateral sides; at least one of the base surfaces disposed with a predetermined winding arc around a pulley from which it receives or, to which it transmits, motion by friction. The sides of the annular body are inactive for transmitting the forces by friction. The belt that is for example, flat, is extensible, and it comprises at least one group of three layers in direct contact with one another, each layer of which includes or comprises reinforcing fibers disposed in a single predetermined direction. In the reinforcing structure no inextensible cords are present. The belt may comprise an annular element on at least one of the base surfaces of the annular body, for opposing any lateral shifting relative to the transmission pulley.

Flexible belt and its associated transmission

A V-belt (1) comprising at least three layers (2, 3, 4) of elastomeric material embedding discontinuous fibers (5, 6, 7); one of the layers (2) comprises fibers (5) directed transversally to the belt longitudinal direction and the two remaining layers (3, 4) comprise fibers (6, 7) mutually inclined in opposite direction with respect to the belt longitudinal direction X--X, the layers in which the fibers are inclined in the belt longitudinal direction having an equal extensibility. The three layers are in direct mutual contact and the belt is devoid of inextensible longitudinal reinforcement strands or the like. In some embodiments, the belt may be part of a two-pulley transmission, in particular for stepless speed change gears, where only one pulley is of the expanding type.

V-belt of controlled extensibility and relative transmission

V-belt of flexible polymeric material, in particular elastomeric material, comprising at least in the portion whose ends are destined to contact the pulley a plurality of layers, each one having fibers oriented in a single direction. The layers are alternately overlapped, some with the fibers oriented substantially in a longitudinal direction, the others oriented in a substantially transverse direction, the thickness of each layer being less or at most equal to the average length of the fibers present in the layer. Preferably, the V-belt is a cogged or toothed belt.

V-belt

The invention relates to an antivibration device particularly adapted for mounting motorcar engines, comprising a shaft (2) fixed to a base and supporting above it a metallic plate (3), fixing one extremity of a metallic container cylinder (4) inside which there is axially positioned a shaft (5) bearing the static work preload by means of a spacer spring (7) interposed between the plate (3) and a plate (6) held at one extremity of the same shaft (5), rigid revolving elements (9) being disposed between a viscoelastic material rolling race (10), preferably sheathing the shaft (5), and a metallic sliding race (8) consisting of a groove made in the inner wall of the container cylinder (4) in which the said rigid revolving elements are housed.

Antivibration device particularly adapted for an automotive engine

An elastic joint for the transmission of motion between a driving shaft and a driven shaft, comprising in effect two tetrahedrons joined together along one edge. The two tetrahedrons are constituted by eight edges formed by flexible elements resistant to tensile stresses; the furthermost edges and the joining edge are formed of material resistant to compression stresses.

Transmission joint

A power transmission belt which is substantially V-shaped in cross-section has insert members which are resistant to transverse compression embedded in an elastomeric or plastomeric body. Protective layers of elastomer or plastomer having oriented fibers dispersed therein cover the flanks of the belt and, if necessary, are disposed in addition to the belt body adjacent to a base of the belt.

Growing community of inventors

Milan, Italy

Edoardo Robecchi