Pirelli Transmissioni Industriali S.p.a.

Dayco Pti S.p.a.

Carlo Fiordaliso

Vincenzo Macchiarulo

Tommaso Di Giacomo

Franco Cipollone

Tommaso DiGiacomo

In an endothermic engine there are two dynamic balancing shafts driven in rotation in respectively opposite directions, at a speed twice that of the rate of rotation of the crankshaft. The dynamic balancing shafts are driven by a toothed belt transmission (1), comprising a driving pulley (2) keyed on the crankshaft, two driven pulleys (3, 4) keyed on the balancing shafts and a tensioning pulley (5) rotatably engaged with the base. The pulleys (2, 3, 4, 5) are connected together by a belt (6) having an internal (9) and external (10) toothing with a toothing pitch (P) equal to 7.5 mm, and provided with a resistant insert (7) formed by glass fibre cords (8) having a diameter equal to 0.9 mm.

Toothed belt transmission for driving dynamic balancing shafts in

In an endothermic engine there are two dynamic balancing shafts driven in rotation in respectively opposite directions, at a speed twice that of the rate of rotation of the crankshaft. The dynamic balancing shafts are driven by a toothed belt transmission (1), comprising a driving pulley (2) keyed on the crankshaft, two driven pulleys (3, 4) keyed on the balancing shafts and a tensioning pulley (5) rotatably engaged with the base. The pulleys (2, 3, 4, 5) are connected together by a belt (6) having an internal (9) and external (10) toothing with a toothing pitch (P) equal to 7.5 mm, and provided with a reinforcing structure (7) formed by glass fibre cords (8) having a diameter equal to 0.9 mm.

A toothed belt is provided which is made of an elastomeric material or the like and which comprises a plurality of teeth, alternating with spaces, covered with at least one layer of textile material. The elastomeric material forming the top of at least one tooth and the relative covering textile material layer are shaped to define at least one depression limited by two lateral protuberances. The seam joining the textile layer end portions is situated along the depression so that no rubbing can take place between the seam and a surface external to the belt. Preferably, the depression botton is formed to have a curvilinear shape and the ratio between the thickness 's' of the covering textile material layer and the bending radius 'r' of the depression bottom ranges between 0.1 and 10.0.

Toothed belts

A V-belt for continuous speed variators and which is formed of a visco-elastomeric material and includes a group of teeth formed on upper and lower parts thereof. The two groups of teeth are opposed to one another with each having a substantially equal base-surface. Each of said teeth is at least partially covered by a stiffening element that is oriented transverse to the belt and extends to opposite sides of the belt. Lateral surfaces of each pair of opposing teeth for contacting with corresponding pulleys are comparable in shape.

Growing community of inventors

Citia's Angelo, Italy

Carlo Fiordaliso