摘要:
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.
摘要:
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.
摘要:
A toothed belt (1) having between its teeth (7) and the grooves (8) adjacent to the said teeth curvilinear connection segments (17) whose ends are located on the end of the tooth flank and the base line delimiting the grooves. The first end (18) of the curvilinear connection segment coincides with the first terminal point of an arc (20) tangent to the end of the flank and to the base line delimiting the grooves, the second end (19) of the curvilinear segment being located between the second point (21) of the said arc and the point of intersection (22) of the central axis of the groove L-L and the base line. Preferably, the toothed belt forms part of a transmission member including pulleys in which at least one of the pulleys is provided with teeth (24) filleted laterally with respect to the adjacent grooves (23) by curvilinear segments (31, 32) shaped to correspond to the curvilinear connection segments of the belt. Preferably, the curvilinear connection segments of the belt and of the pulley are parabolic arcs.
摘要:
In a process for manufacturing toothed belts of any length, a tubular sleeve comprising a layer of cords (1) and at least a layer of elastomeric material (2) is preformed in an autoclave without being vulcanized so as to produce, on the inner surface thereof, a plurality of grooves (5) spaced apart from one another according to a predetermined toothing pitch (P). The sleeve is helically cut to obtain a continuous strip (7) to be subsequently wrapped over two wrapping drums (8, 9) suitably spaced apart from each other depending on the circumferential extension to be given to the belt. The obtained annular element (10), when the wrapping has been completed, is trued up by means of the provided grooves, between a molding matrix (11) and opposite mould (12) and is submitted to a pressing step and simultaneous cross-linking of the elastomeric material (2) by closing said elastomeric material between the molding matrix (11) and opposite mold (12) according to stages in succession. Thus the complete formation of the teeth (3) on the inner side of the belt being worked occurs, as well as the firm bonding of the continuous loops (10a) formed by wrapping of the continuous strip (7).
摘要:
A toothed belt having between its teeth and the grooves adjacent to the teeth curvilinear connection segments whose ends are located on the end of the tooth flank and the base line delimiting the grooves. The first end of the curvilinear connection segment coincides with the first terminal point of an arc tangent to the end of the flank and to the base line delimiting the grooves, the second end of the curvilinear segment being located between the second point of the arc and the point of intersection of the central axis of the grooves and the base line.
摘要:
In a process for manufacturing toothed belts of any length, a tubular sleeve comprising a layer of cords (1) and at least a layer of elastomeric material (2) is preformed in an autoclave without being vulcanized so as to produce, on the inner surface thereof, a plurality of grooves (5) spaced apart from one another according to a predetermined toothing pitch (P). The sleeve is helically cut to obtain a continuous strip (7) to be subsequently wrapped over two wrapping drums (8, 9) suitably spaced apart from each other depending on the circumferential extension to be given to the belt. The obtained annular element (10), when the wrapping has been completed, is trued up by means of the provided grooves, between a molding matrix (11) and opposite mould (12) and is submitted to a pressing step and simultaneous cross-linking of the elastomeric material (2) by closing said elastomeric material between the molding matrix (11) and opposite mold (12) according to stages in succession. Thus the complete formation of the teeth (3) on the inner side of the belt being worked occurs, as well as the firm bonding of the continuous loops (10a) formed by wrapping of the continuous strip (7).
摘要:
A method and apparatus for carrying out the checking of the state of wear of a covering fabric in a driving belt (2) mounted on a plurality of pulleys (3, 4, 5) by measuring the electric resistance variations of the belt fabric. The apparatus provides that at least two of the pulleys (3, 4, 5) should be electrically insulated with respect to each other and connected to an electric circuit (20) designed to apply an electric voltage to said pulleys in order to carry out the measuring of the electric resistance of the fabric exhibited by belt stretches (A, B) comprised between the pulleys themselves. The electric resistance thus found lends itself to be compared with predetermined resistance values corresponding to different states of wear of the belt (2) fabric. The work surface of the belt (2) is coated with an electrically conductive fabric (12) acting by contact on the pulleys (3, 4, 5) and having characteristics of tensile strength.
摘要:
A toothed pulley is provided which includes a plurality of grooves alternating with a plurality of teeth. The flank of each groove is joined to the head of the adjacent tooth by a connection formed of at least two convex curvilinear segments and a recess. The curvilinear segments are tangent to the end of the flank and to the terminal point of the tooth head delimitated by the outer circumference of the pulley respectively. The pulley engages with a toothed belt which includes a connection between the tooth flank and the adjacent groove, which may be in the form of a parabolic arc.
摘要:
Toothed belt in which the toothed part is covered with a fabric consisting of a warp and a weft consisting of weft threads formed by an elastic thread, preferably made from polyurethane, acting as the core, and by at least a pair of composite threads wound on the elastic thread. Each composite thread comprises a thread with high heat resistance and high strength, preferably made from para-aromatic polyamide, and a covering thread, preferably made from nylon, wound on the thread with high heat resistance and high strength. The structure of the weft of the toothed belt is such that each thread with high heat resistance and high strength can be completely isolated in such a way that it is not damaged by the friction of the belt against the teeth of the pulley, ensuring a greater durability of the belt. The structure with a pair of composite threads also makes it possible to increase the breaking load of the fabric.
摘要:
A toothed belt comprising a body made of elastomeric material, embedded in which is a plurality of longitudinal filiform resistant inserts, and comprising a toothging coated with a coating fabric; on top of the coating fabric a resistant layer is made to adhere, which increases the resistance to wear of the toothed belt and which comprises a fluorine-based plastomer with elastomeric material added, in which the plastomer is present in an amount greater than that of the elastomeric material. Preferably, the plastomer is polytetrafluoroethylene, and the elastomeric material comprises HNBR. Advantageously, the resistant layer has a thickness of between 0.01 and 1.5 mm, and between the coating fabric and the resistant layer is set an adhesive material.