Crankshaft for internal combustion engine, comprises a reference crank pin, a first crank pin and a second crank pin, axes parallel to an axis of the crankshaft, and a first arm extending radially between the first crank pin and a swivel

摘要

The crankshaft (1) comprises a reference crank pin (3), a first crank pin (4) and a second crank pin (5), axes parallel to an axis (2) of the crankshaft and located in three directions distributed at 120[deg] around the axis of the crankshaft, and a first arm extending radially between the first crank pin and a swivel (7). The first arm has a side directed towards the side of the first crank pin and a side directed towards the side of the pin. One of the sides of the first arm comprises a removable reinforcement either with respect to a main plane of the crankshaft. The crankshaft (1) comprises a reference crank pin (3), a first crank pin (4) and a second crank pin (5), axes parallel to an axis (2) of the crankshaft and located in three directions distributed at 120[deg] around the axis of the crankshaft, and a first arm extending radially between the first crank pin and a swivel (7). The first arm has a side directed towards the side of the first crank pin and a side directed towards the side of the pin. One of the sides of the first arm comprises a removable reinforcement either with respect to a main plane of the crankshaft passing through the axis of the crankshaft in the reinforcement of the swivel or with respect to a plane of the local joint passing through the axis of the first crank pin in the reinforcement. The plane of the local joint and the main plane are perpendicular to the direction of the reference crank pin. The reinforcement comprises an end extending radially to the outside of the corresponding crank pin or swivel. An end is bounded by a stop having an upper part and a lower part on both sides of the local joint or the main plane. Each of the parts has a minimum relief angle with respect to the direction of the reference crankpin. The first arm has a symmetrical form with respect to a symmetrical plane passing through the axis of the crankshaft and the axis of the first pin. The side near crankpin and side near the swivel comprise a shoulder having the form of a fillet between a projection surface forming the reinforcement and located axially near crankpin and an axial surface in a recess, respectively. The fillet of one side of the crankpin and swivel has an upper part and a lower part on both sides of the local joint plane of the reinforcement of the crankpin, respectively. The upper part is located on the same side of the local joint plane as the reference crank pin. The upper part of the fillet and swivel comprises a central portion perpendicular to the plane and a side portion at distance from the plane, respectively. The lower part of the fillet and the lateral portion are symmetric with respect to the plane of the first crank. The surface projection of the side near the crankpin surrounds the crankpin. The recessed surface of the side near the crank extends radially along the axis of the crankshaft. A first mass of inertia is located in a same radial plane as the first arm and diametrically opposite to the first crankpin. The second crankpin is connected to the swivel with respect to a second arm having the characteristics of the first arm. An independent claim is included for a mold for molding a crankshaft for an internal combustion engine.