A shaft balancing device for insertion into a shaft including a generally flat cylindrical band having an outer surface, an inner surface and a set of two crush points thereon. A balancing weight is attached to the outer surface of the band between the set of crush points. The device is inserted into the shaft and the crush points are plastically deformed radially outward creating spring force which holds the balancing weight to the inner surface of the shaft. The band has a curved connecting portion between the two crush points having a radius of curvature slightly greater than the curvature of the shaft. The balancing weight has a radius of curvature slightly greater than the radius of curvature of the curved connecting portion and slightly less than the radius of curvature of the shaft.

The present invention provides a rotary engine comprising: a housing provided with three lobe accommodation parts; a rotor which is provided with two lobes continuously accommodated in the lobe accommodation parts, has an intake storage part communicating with an intake port provided on the front surface-side, and has an exhaust storage part communicating with an exhaust port provided on the rear surface-side; an intake-side housing cover provided with an intake hole communicating with the intake storage part; an exhaust-side housing cover provided with an exhaust hole communicating with the exhaust storage part; and a crankshaft, wherein the flow of an exhaust gas into a stroke chamber during an intake stroke is reduced by preventing the exhaust storage part, at a portion of a section in which the exhaust port is open, from communicating with the exhaust hole during the intake stroke.

The present invention provides a rotary engine comprising: a housing provided with three lobe accommodation parts; a rotor which is provided with two lobes continuously accommodated in the lobe accommodation parts, has an intake storage part communicating with an intake port provided on the front surface-side, and has an exhaust storage part communicating with an exhaust port provided on the rear surface-side; an intake-side housing cover provided with an intake hole communicating with the intake storage part; an exhaust-side housing cover provided with an exhaust hole communicating with the exhaust storage part; and a crankshaft, wherein the flow of an exhaust gas into a stroke chamber during an intake stroke is reduced by preventing the exhaust storage part, at a portion of a section in which the exhaust port is open, from communicating with the exhaust hole during the intake stroke.

The present disclosure shows a crankshaft having at least one counterweight that is preferably screwed to the crankshaft via at least two screws, with the counterweight having a contact surface at which it contacts a counter-contact surface of the crankshaft. In this respect, the position of the counterweight at the crankshaft is fixed via at least one positioning element independent of the screw connection.

A balance shaft includes an unbalanced shaft (3) comprising a bearing journal (8, 9), the periphery of which is merely partially cylindrical. The cylindrical partial periphery (10) of the bearing journal is oriented toward the shaft imbalance. The balance shaft also includes a needle roller cage assembly (15); and a bearing ring (13), which extends around the bearing journal, lies against the cylindrical partial periphery and forms the inner raceway of the needle roller cage assembly. The cage (27) of the needle roller cage assembly is designed to run on the end faces of the bearing ring axially on both sides by means of radially inwardly extending projections.

The rotary body according to the present invention is made of resin and attached to a crankshaft. The rotary body has an outside plate element and an inside plate element which are attached to an outside surface and an inside surface of an arm portion of the crankshaft, respectively, and a pair of filler elements disposed between the outside plate element and the inside plate element and on both sides of the arm portion. The outside plate element and the pair of the filler elements are coupled to each other, and the pair of the filler elements and the inside plate element are coupled to each other.

The rotary body according to the present invention is made of resin and attached to a crankshaft. The rotary body has an outside plate element and an inside plate element which are attached to an outside surface and an inside surface of an arm portion of the crankshaft, respectively, and a pair of filler elements disposed between the outside plate element and the inside plate element and on both sides of the arm portion. The outside plate element and the pair of the filler elements are coupled to each other, and the pair of the filler elements and the inside plate element are coupled to each other.

A balance shaft includes an unbalanced shaft (3) comprising a bearing journal (8, 9), the periphery of which is merely partially cylindrical. The cylindrical partial periphery (10) of the bearing journal is oriented toward the shaft imbalance. The balance shaft also includes a needle roller cage assembly (15); and a bearing ring (13), which extends around the bearing journal, lies against the cylindrical partial periphery and forms the inner raceway of the needle roller cage assembly. The cage (27) of the needle roller cage assembly is designed to run on the end faces of the bearing ring axially on both sides by means of radially inwardly extending projections.

A crankshaft for an internal combustion engine is provided. The crankshaft comprises at least four main journals aligned on a crankshaft axis of rotation defining a centerline. The crankshaft further comprises at least three pin journals. Each pin journal is disposed about a respective pin journal axis and positioned between the main journals. Each of the pin journals is joined to a pair of crank arms. Each pair of crank arms is joined to a respective main journal. Each of the main journals, pin journals, and crank arms is made of a first metallic material. Each crank arm has an over-molded counterweight metallurgically bonded thereto. Each counterweight is disposed opposite a respective pin journal relative to the centerline for balance and stability. Each counterweight is made of a second metallic material. The crankshaft has a weight ratio of the second metallic material to the first metallic material of between 0.20 to 0.50.

A crankshaft for an internal combustion engine is provided. The crankshaft comprises at least four main journals aligned on a crankshaft axis of rotation defining a centerline. The crankshaft further comprises at least three pin journals. Each pin journal is disposed about a respective pin journal axis and positioned between the main journals. Each of the pin journals is joined to a pair of crank arms. Each pair of crank arms is joined to a respective main journal. Each of the main journals, pin journals, and crank arms is made of a first metallic material. Each crank arm has an over-molded counterweight metallurgically bonded thereto. Each counterweight is disposed opposite a respective pin journal relative to the centerline for balance and stability. Each counterweight is made of a second metallic material. The crankshaft has a weight ratio of the second metallic material to the first metallic material of between 0.20 to 0.50.