An engine system is provided with a crankshaft gear coupled to a crankshaft of an engine for rotation therewith, and a balance gear coupled to a balance shaft for rotation therewith. The balance gear and crankshaft gear are in meshed engagement. The balance gear is formed by a series of sectors connected by a series of resilient blocks, with each sector defining first and second recesses along opposite radial edges sized to receive adjacent blocks, respectively. Each elastomeric block is configured to deform both normally and in shear thereby providing damping for the gear. A gear such as the balance gear, and a method of forming the gear are also provided.

An unbalanced crankshaft mounted accessory is configured to externally balance the rotating assembly of a particular engine model. In one embodiment, the unbalanced crankshaft mounted accessory is attached to the crankshaft at the output of the crankshaft (i.e., the connection to a load driven by the engine). The accessory is unbalanced at an angle and weight configured to reduce deflection of the crankshaft at the output of the crankshaft (when the unbalanced crankshaft mounted accessory is attached). The weight and angle are determined by measuring crankshaft deflection at various speeds (rpm) throughout the recommended operating range of the engine. The angle and deflection distance are then averaged and multiplied against a rotating mass of the engine and a constant to determine an angle and weight for the unbalanced crankshaft mounted accessory.

Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

To provide a vehicle that includes a balancer mechanism for reducing vibration of the engine and can leave a space margin for increasing the fuel tank in size and/or arranging equipment or components at the rear of the cylinder and above the crankcase. A vehicle includes: an engine mounted on a body frame. The engine comprises a crankcase with a ceiling wall, a crankshaft provided in the crankcase, and a balancer mechanism for reducing vibration of the engine by power transmitted from the crankshaft. The balancer mechanism comprises an idler gear disposed behind the crankshaft and rotated by power transmitted from the crankshaft, and a first balancer disposed behind the idler gear and rotated by power transmitted from the idler gear. The idler gear and the first balancer are disposed along the ceiling wall.

The invention relates to a power unit, in particular for a hybrid vehicle, comprising a two-cylinder reciprocating piston engine comprising two pistons guided in two cylinders in tandem arrangement, and two counter-rotating crankshafts connected to the pistons by connecting rods, a generator which is rotatable in the same direction as the first crankshaft and in the opposite direction to the second crankshaft, and a balancer shaft which is rotatable in the same direction as the second crankshaft and in the opposite direction to the first crankshaft. The generator is operatively connected directly to the first crankshaft by a first traction mechanism and the balancer shaft is operatively connected directly to the second crankshaft by a second traction mechanism. The balancer shaft and/or the second crankshaft support(s) a flywheel mass element. The invention further relates to a vehicle, in particular a hybrid vehicle, having such a power unit.

An unbalanced crankshaft mounted accessory is configured to externally balance the rotating assembly of a particular engine model. In one embodiment, the unbalanced crankshaft mounted accessory is attached to the crankshaft at the output of the crankshaft (i.e., the connection to a load driven by the engine). The accessory is unbalanced at an angle and weight configured to reduce deflection of the crankshaft at the output of the crankshaft (when the unbalanced crankshaft mounted accessory is attached). The weight and angle are determined by measuring crankshaft deflection at various speeds (rpm) throughout the recommended operating range of the engine. The angle and deflection distance are then averaged and multiplied against a rotating mass of the engine and a constant to determine an angle and weight for the unbalanced crankshaft mounted accessory.

An internal combustion engine includes: a crankshaft supported via a bearing; a balancer drive gear; a balancer shaft; and a one-way clutch mechanism that transmits to the crankshaft a drive force to start the internal combustion engine. In the internal combustion engine, the bearing includes an oil seal built therein, the oil seal sealing a crank chamber of the crankcase. The one-way clutch mechanism includes a case fixed to the crankshaft and a starter driven gear provided relatively rotatably with respect to the case and driven by the drive force. The starter driven gear includes a thrust bearing portion that abuts on the balancer drive gear in an axial direction of the crankshaft.

A bearing cap according to one embodiment of this disclosure includes: a concave part that supports a crankshaft of an internal combustion engine; first bosses that are disposed one on each side of the concave part and each have a first bolt hole; and second bosses that are disposed one on each side of a bearing cap main body having the concave part and the first bosses so as to flank the bearing cap main body and each have a second bolt hole. The bearing cap is fixed to a first member of the internal combustion engine by first bolts inserted into the first bolt holes, and to a second member of the internal combustion engine by second bolts inserted into the second bolt holes. At least the pair of second bosses have higher rigidity than a frame.

Oil pump and oil pump-integrated balancer device each have a pump housing formed by housing body 31 and cover member 32, pump shaft 33 having driven side helical gear 43 at which thrust force occurs when transmitting rotation force and rotating a rotor by the rotation force provided from drive side helical gear 13 that is engaged with driven side helical gear 43, first and second thrust receiving portions 47, 46 formed close to hole edges of bearing holes 32a, 31a of the cover member and the housing body, and first and second thrust limiting portions 49, 48 provided at the driven side helical gear and the pump shaft, contacting the thrust receiving portions from axis direction and limiting thrust movement of the pump shaft. With this configuration, oil pump and oil pump-integrated balancer device which are capable of securing stable support of the pump shaft are provided.

A balance shaft structure includes a balance shaft including a balance weight, a driven gear to rotate the balance shaft by being engaged with a drive gear, a scissors mechanism, whose position in an axial direction is regulated, including a scissors gear to reduce backlash between the drive gear and the driven gear and an axially urging member to urge the scissors gear toward the driven gear in the axial direction, a first regulating portion to regulate an axially inner position of the scissors mechanism, and a second regulating portion fixed to the balance shaft on a side close to the shaft end part of the balance shaft beyond the first regulating portion and configured to regulate an axially outer position of the scissors mechanism.