Abstract: A power unit for a motorcycle includes an internal combustion engine provided with a crankcase rotatably supporting a crankshaft with an axial line extending in a vehicle-width direction. An oil pump is mounted on the crankcase with a balancer rotatably supported by the crankcase. Rotational power from the crankshaft is transmitted to a pump driven member provided on a pump shall of the oil pump and to a balancer driven member coaxially interlinked with and connected to the balancer so as to transmit power to the balancer. The power unit is downsized by bringing a balancer and an oil pump into a close arrangement. The pump driven member and the balancer driven member are offset from each other in a vehicle-width direction and are located at such a position so as to at least partially overlap each other as viewed from the side of the vehicle-width direction.

Abstract: A compensating drive for driving a compensating shaft of an internal combustion engine, comprising a toothed belt or a chain, which connects a crankshaft driven wheel of the internal combustion engine to a drive wheel on the compensating shaft or shafts, in which case the crankshaft driven wheel (2, 2?) and/or the drive wheel or wheels (5) of the compensating shafts (4) are shaped to be non-circular in such a way that they transmit to the drive a variability, which at least partially compensates the vibrations produced during the rotation of the crankshaft (1).

Abstract: A method of operating an engine having an adjustable balance shaft may comprise adjusting operation of the balance shaft during engine operation in response to an engine combustion mode. For example, balance shafts may be disabled during SI mode and enabled during HCCI mode. Various alternative examples may also be used.

Abstract: F&C engine includes a central shaft mounted a cylindrical cam, that formed with two pieces of different diameter steel tubes, as the inner and outer walls, the upper end of the outer wall, placed a driving flange, to drive the engine timing devices. on the two layer walls (for light duty or small engine the single layer wall is acceptable) with pairs of peak and valley channel, a overdrive clutch; inside the cam contained a dynamotor to form a hybrid; a magnetic clutch, for engaging or disengaging the cylindrical cam; a driving plate for driving the devices that not related to the engine timing; a cylinder to produce power and transfer the power to the cam through a push rod; a guide plate to guide the push rod; many support rollers for supporting the cam; a tubular case with foot for contain and support the engine.

Abstract: In a balance shaft for a multi-cylinder in-line engine with at least two imbalance weight sections and at least one bearing structure wherein the balance shaft has imbalance weight sections being arranged symmetrically relative to the bearing position and at least one of the imbalance weight sections is connected to a further shaft section at an end facing away from the bearing position, a flexible coupling element that enables a deflection of the end of the connected imbalance weight section in the direction of the resulting centrifugal forces when the balance shaft rotates is provided between the end of the at least one imbalance weight section facing away from the bearing position and the further shaft section.

Abstract: [PROBLEMS] To enhance freedom in designing an engine, improve acceleration feeling, provide extremely excellent driving feeling, and enable an engine to be more compact. [MEANS FOR SOLVING PROBLEMS] An in-line four-cylinder engine for a vehicle has a two-plane 90° crankshaft (3). The weight of a crank web for each cylinder is distributed to left and right web half bodies (21a,b-24a,b) to satisfy the expression of (KL?0.25)(0.25?KR)=DR/DL, where KL and KR are balance ratios of web half bodies of each cylinder (where KL?0.25, KR?0.25), and DL and DR are the distances from the center in the longitudinal direction of the crankshaft to each crank web half body. This causes the vector locus of first moment of inertia to be substantially a circle to cancel the first moment of inertia by a primary balancer (6).

Abstract: With a view to reducing the load imposed by a cantilevered balancer weight on a balancer shaft bearing while balancing the inertia force generated by the balancer weights with the center of gravity of a piston and connecting road system, a balancing device for an engine is provided, the device having a second balancer weight which is cantilevered at a position opposing a first balancer weight, wherein the balancer shaft bearing between the first and the second balancer weights is displaced toward the second balancer weight according to the axial direction of the balancer shaft for a certain distance from an intersection Y of the axis of the balancer shaft with a plane passing through the center of gravity Gp of the piston-connecting rod system so that the distance L2 between the intersection Y and the center of gravity G2 of the second balancer weight is longer than the distance L1 between the intersection Y and the center of gravity G1 of the first balancer weight and so that the moment created at the inters

Abstract: An engine balancer system is provided in which a balancer housing (17) disposed so as to face an oil pan beneath a crankshaft is formed by joining an upper housing (29) and a lower housing (30) via mating faces (P), and the height of the mating faces (P) is lower on a vehicle front side than on a vehicle rear side. Oil discharge holes (45a, 46) for discharging oil that is within the balancer housing (17) are formed in the mating faces (P) on the higher side of the balancer housing (17) and in the upper housing (29) above the mating faces (P) on the lower side of the balancer housing (17). This enables the position of the oil discharge hole (45a) on the lower side to be as high as possible, thereby suppressing penetration of oil into the interior of the balancer housing (17) through the oil discharge hole (45a).

Abstract: An engine balancer system is provided in which a balancer housing disposed so as to face an oil pan beneath a crankshaft is formed by joining an upper housing and a lower housing via mating faces, and the height of the mating faces is lower on a vehicle front side than on a vehicle rear side. Oil discharge holes or discharging oil that is within the balancer housing are formed in the mating faces on the higher side of the balancer housing and in the upper housing above the mating faces on the lower side of the balancer housing. This enables the position of the oil discharge hole on the lower side to be as high as possible, thereby suppressing penetration of oil into the interior of the balancer housing through the oil discharge hole.

Abstract: A balancing shaft unit for balancing inertia or torque in an internal combustion engine of a motor vehicle. The balancing shaft unit includes a housing part and at least one balancing shaft having at least one counterweight. The housing part is made in one piece and has at least two integrated bearing sections with a respective bearing opening. A respective cut-out is formed at longitudinal ends of the balancing shaft in which a respective bearing pin is arranged that is rigidly connected to the balancing shaft and which has a cylindrical bearing section that is supported in a respective one of the bearing openings.

Abstract: A tensioner for applying tension to a balancer drive chain is mounted in a balancer housing which accommodates balancer shafts. Oil is supplied from a reservoir chamber to the tensioner. An oil jet member for lubricating the balancer drive chain is mounted at a position downstream in an oil flow direction from the reservoir chamber. Therefore, while enabling foreign matter contained in the oil to be discharged from the oil jet member without being accumulated within the tensioner, a predetermined pressure can be maintained in the reservoir chamber by a resistance to the flow of oil passing through the oil jet member. Also, a constriction is provided between the reservoir chamber and the oil jet member. Therefore, it is difficult for the oil to flow out of the reservoir chamber even after stoppage of an engine, thereby supplying the oil to the tensioner upon the next start of the engine without delay. Thus, it is possible to prevent the foreign matter from entering the tensioner for the balancer drive chain.

Abstract: To provide a pump drive structure for a water-cooled internal combustion engine in which the number of revolving shafts arranged in parallel in an internal combustion engine is reduced and a power transmission mechanism is eliminated. Thus, the internal combustion engine is downsized. The pump drive structure of a water-cooled internal combustion engine is provided in which a balancer shaft is arranged in parallel with a crankshaft at a position where crank webs of the crankshaft and balancer weights are overlapped in the axial direction. An oil pump drive shaft of an oil pump is connected coaxially at one end of the balancer shaft, and a water pump drive shaft of a water pump is connected coaxially with the other end of the balancer shaft.

Abstract: An engine has a built-in continuously variable transmission (CVT) interconnecting a crankshaft connected through a connecting rod to a piston and a transmission shaft to which the rotation of the crankshaft is transmitted for changing speed between both of the shafts. A driven pulley and a clutch are disposed on the transmission shaft. A balancer shaft to which the rotation of the crankshaft is transmitted and the clutch are disposed in an overlapping positional relationship with each other in the direction of the crankshaft.

Abstract: A four-cycle engine of the present invention comprises a gas exhaust outlet that is formed on an upper region of a crankcase to exhaust a gas from the interior of the crankcase to outside; and a rotatable shaft disposed in close proximity to the gas exhaust outlet in the interior of the crankcase. The gas exhaust outlet is configured to open toward a region in the interior of the crankcase, the region extending from a line segment connecting the gas exhaust outlet to a rotational center axis of the shaft, in a rotational direction of the shaft at a cross point where the line segment crosses an outer peripheral surface of the shaft.

Abstract: An oil level sensor for detecting an oil level is arranged in an engine oil pan. The oil level sensor includes a mounting section and a sensing section. An air hole is formed at an upper end of a cover member of the sensing section. The air hole is surrounded by a tubular portion of a shield member attached to a baffle plate of the oil pan. Therefore, any splashed engine oil in the oil pan is restricted from entering the cover member of the sensing section through the air hole. Also, a clearance (?) for venting air is formed between the tubular portion and the baffle plate.

Abstract: The invention relates to a balancing shaft, whose balancing weight is located between two cylindrical bearing surfaces and which is configured as one piece with said weight. The end cross-sections of the balancing weight are circular segments that are delimited by an arc and a secant. The aim of the invention is to configure the balancing shaft in such a way that the mass effect and rigidity are optimal. To achieve this, the contours of the balancing weight on the plane that is fixed by the secants of the two end cross-sections taper from the two end cross-sections towards the longitudinal centre and the contours on the normal plane form a straight line in relation to said plane.

Abstract: A counterweight arrangement for an internal combustion engine with three cylinders. The internal combustion engine having a crankshaft rotating about an axis of rotation, with three cranks which succeed one another in the axial direction with respect to the axis of rotation and are distributed at angular intervals of 120° and each crank corresponding to a respective cylinder, the counterweight arrangement including at least two counterweights for at least partial compensation of inertia forces caused by rotating masses on the crankshaft, wherein exactly two counterweights are provided for the two outer cranks, at least one of the two counterweights being arranged in a position which is rotated about the crankshaft axis with respect to an assigned crank through angle (?counter), the amount of which differs from 30°+N*180°, N being equal to a natural number or equal to zero.

Abstract: A piston engine with a compensation shaft unit, wherein a window surrounded by a flange is provided on the crankcase thereof. The flange forms a separating surface to which the housing of the compensation shaft unit is fixed by means of screws. In order to ensure clean, toothed-wheel engagement for the compensation shafts, which are integrated into the housing, and easy assembly, the compensation shaft is provided with a toothed wheel, which protrudes through the window inside the crankcase, and which is driven by a toothed wheel, which is arranged on the crankshaft, and the housing of the compensation shaft unit has a separating surface, which can be displaced in order to adjust the amount of engagement clearance on the separating surface of the crankcase before the screws are tightened.

Abstract: To provide a power unit capable of contributing to simplifying the procedure for fitting the electric motor for speed change use and the starter motor to shorten the motor wiring to facilitate the wiring and for concentrating the mass. A power unit includes a unit case which is journaled in a front part to a pivot shaft and a belt-driven continuously variable transmission is provided together with an internal combustion engine. An electric motor for transmission and a starter motor are provided together and supported by the unit case. The electric motor and the transmission are arranged to be adjoining each other on the same side as the pivot shaft in a side view. The electric motor for transmission is arranged in a position closer to the pivot shaft than the starter motor.

Abstract: An internal combustion engine includes a piston (2) and a crankshaft (33). The crankshaft (33) includes: a journal (33A) as a rotation center; a crank pin (33B) that is located eccentrically with respect to the journal (33A) and rotates integrally with the journal (33A), the crank pin (33b) connecting the piston (2) to the crankshaft (33); and a counter weight (33C) that is located eccentrically with respect to the journal (33A) in a direction opposite to the crank pin (33) and rotates uniformly with the journal (33A). A cutout (11) through which the counter weight (33C) passes is formed in a wall (1) of a cylinder bore that accommodates the piston (2) so as to be free to move reciprocally along the wall (1). As a result, the bottom dead center position of the piston can be lowered, and the overall height of the engine can be decreased.

Abstract: A balancer driven gear of an engine, for the transfer of rotation of the crankshaft to a balancer shaft, is made up of a gear member, a bush member and elastic members and interposed therebetween. The bush member has a boss portion fixed to the balancer shaft, and a plurality of outward dowels projecting radially outward from the outer periphery of the boss portion. The gear member is disposed coaxially with the bush member. The gear member has an annular portion with gear teeth on the outer periphery thereof and a plurality of inward dowels projecting radially inward from the inner periphery of the annular portion. Elastic members are disposed between the outward dowels on the bush member 20 and the inward dowels on the gear member. The shapes and/or dimensions of the dowels positioned on opposite sides with respect to the axis of the balancer driven gear are made asymmetric.

Abstract: A rotational balance adjustment structure for an engine includes; a damper pulley having an elastic member provided on the outer periphery of a hub and a damper mass provided on the outer periphery of the elastic member; and an engine assembly having an engine body and a plurality of parts mounted on the engine body, the plurality of parts including the damper pulley. The engine assembly is assembled by mounting a plurality of parts to the engine body, the plurality of parts including the damper pulley, and the rotational balance of the engine assembly is adjusted by attaching a balance piece to the damper mass.

Abstract: A balancer apparatus including a first balancer and a second balancer. The first balancer includes a first balance weight and the second balancer includes a second balance weight and wherein the first and second balance weights are asymmetrical. The first and second balancers include first and second center of gravities that are longitudinally aligned when the first and second balancers are assembled in a housing.

Abstract: A noise suppressing mechanism for balance gear system of an engine crankshaft is disclosed. The balance gear system includes a primary gear, a secondary gear, and a torsional spring and is fit on a balance shaft. The noise suppressing mechanism includes a circular flange formed on the primary gear and the secondary gear forms a central bore rotatably fit over the circular flange for free rotation about the circular flange with respect to the primary gear. The torsional spring is arranged between the primary and secondary gears. The primary gear forming a securing hole in which a stem section of a limiting pin is received and fixed. The secondary gear forms a through hole in which a head section of the limiting pin is accommodated with a gap formed between the head section and an inside diameter of the through hole. The gap allows for a limited angular shift of the secondary gear with respect to the primary gear.

Abstract: An engine balancer system is provided in which a balancer housing disposed so as to face an oil pan beneath a crankshaft is formed by joining an upper housing and a lower housing via mating faces, and the height of the mating faces is lower on a vehicle front side than on a vehicle rear side. Oil discharge holes or discharging oil that is within the balancer housing are formed in the mating faces on the higher side of the balancer housing and in the upper housing above the mating faces on the lower side of the balancer housing. This enables the position of the oil discharge hole on the lower side to be as high as possible, thereby suppressing penetration of oil into the interior of the balancer housing through the oil discharge hole.

Abstract: An idler shaft assembly for an internal combustion engine provides significant cost savings eliminates processing and assembly steps, and provides accurate orientation of components. The idler shaft assembly includes a shaft adapted for rotation about a first axis. A one-piece sprocket and gear assembly is received on the shaft. A sprocket portion of the one-piece assembly has a first diameter that cooperates with an associated drive chain that is driven by the crankshaft, and a gear portion of the one-piece assembly has a second diameter that cooperates with an associated gear of an associated balance shaft.

Abstract: A drive system for an internal combustion engine including an endless chain connecting a drive sprocket on a crankshaft to a driven sprocket on a camshaft. The drive system is comprised of at least one balance shaft and a torsion bar. The balance shaft has a first end for connection to the drive sprocket and a center bore. The torsion bar is located within the center bore of the balance shaft. The torsion bar has a first end for connection to the drive sprocket and a second end fixedly attached to the inner end of the center bore. The torsion bar absorbs torsional vibrations and isolates torsional vibrations due to inertia of the balance shaft caused by the crankshaft. Bearings are located between the first end of the torsion bar and the center bore of the balance shaft, to center the torsion bar within the balance shaft.

Abstract: A crankshaft for a V-type six-cylinder engine is equipped with first through sixth crankpins, first through fourth crank journals, and first through ninth arms for connecting the crank pins and the crank journals to each other. Of the first through ninth arms, the third arm and the seventh arm respectively have surplus weight portions (inclusive of counterweights) whose centers of gravity are situated respectively in a direction substantially opposite the first crank pin and the sixth crank pin.

Abstract: A oil supply apparatus includes a pair of balancer shafts arranged at an upper space of an oil pan provided at a lower part of an engine, a scavenge pump activated by one of the pair of balancer shafts, and a feed pump activated by the other of the pair of balancer shafts.

Abstract: An internal combustion engine is provided for a personal watercraft in which a portion of the engine that is enlarged to accommodate a balance shaft is minimized in size, whereby the internal combustion engine is made compact. Balance shafts for preventing secondary vibration are arranged together with a crankshaft on a dividing plane between a crankcase and a cylinder block of an internal combustion engine. The balance shafts lie mutually in parallel with the crankshaft. A crankshaft bearing is formed in the dividing plane on each of plural mutually opposed, longitudinally spaced rib pairs, and balance shaft bearing is formed in the dividing plane on a selected rib pair of the plural rib pairs. The balance shaft bearing is positioned so as to be biased in a direction in which the balance shaft bearing is closer to an adjacent rib compared with the crankshaft bearing.

Abstract: In a cover plate for obturating a crankcase of an internal combustion engine at the bottom end thereof, which cover plate includes suction areas for collecting engine lubricant and on which a balancing shaft is rotatably supported and driven by the crankshaft of the engine via a gear structure, a first gear pump is arranged at one end of the balancing shaft for pumping lubricant from a collection area at the one end of the balancing shaft and a second gear pump is disposed at the opposite end of the balancing shaft for pumping lubricant from the other collection area at the other end of the balancing shaft, each pump having one of its gears mounted on the balancing shaft.

Abstract: The present invention is an engine, including two banks of cylinders in a flat, opposed cylinder arrangement and a crankshaft having a plurality of paired throws, the two throws of each respective pair of throws being disposed adjacent to each other and coplanar with respect to each other.

Abstract: A system and method for managing inertial torque reaction of a powertrain include a selectively engageable counter-rotating component to reduce or eliminate torque reaction on stationary powertrain structure. Selectively engageable counter-rotating inertia may be provided by a simple inertial mass or by an electrical machine functioning as an integral starter/generator (ISG) to provide vehicle launch assist, regenerative braking of the vehicle, and engine cranking. Embodiments include gear-driven, chain-driven, and belt-driven counter-rotating inertias selectively coupled for counter-rotation relative to the crankshaft by a clutch, a belt-driven pulley assembly, or chain-driven intermediate shaft assembly with a hydraulically actuated coupling pin.

Abstract: An engine is constructed such that respective centers of gravity of a crank shaft, a balancer shaft and a cylinder are positioned close to one another and the mass of the engine is thus centralized. The engine includes a shaft center of a cylinder that is offset to one side with respect to a shaft center of a crank shaft, and a balancer shaft is disposed on a side of the engine where the cylinder shaft center is offset with respect to a first parallel line which intersects with the crank shaft center and extends substantially parallel to the cylinder shaft center.

Abstract: An engine starter mechanism arrangement for snow vehicles, in which a starter mechanism is disposed so as to maintain excellent traveling stability of the snow vehicle. A crankshaft (7) extends through an engine (2) in a transverse direction of a body frame. A rear balancer shaft (62) is disposed in a rear part of the engine at a location rearward of the crankshaft in a manner extending substantially parallel to the crankshaft. A starter motor (65) is disposed in the engine at a location above the rear balancer shaft.

Abstract: A rotating cylinder valve engine provides variable compression to the engine by axially moving the rotatable cylinder towards or away from the piston. The volumetric center of the combustion chamber is offset from the central axis of the piston. The engine cylinder is also ported to optimize performance.

Abstract: To miniaturize an engine, to concentrate heavy masses and to reduce friction loss of a balancer. An engine crankcase structure in which a crankcase is vertically partitioned into an upper case and a lower case, each journal supporter is formed in the upper case and in the lower case so that the rotational axis of a crankshaft is located on a partition face of the crankcase in parallel with a direction of the width of the body. The crankshaft is supported so that the crankshaft can be rotated. An oil filter is directly attached to the lower case. An oil cooler and a secondary balancer are arranged in the front of the lower case.

Abstract: A lubricating structure for engines, wherein an oil feed pump and an oil recovery pump are disposed so as to avoid interference between the oil feed and recovery pumps and a clutch mechanism and an increase in the size of the engine. The clutch mechanism 38 is disposed at a location toward a left end of a crankshaft 7 as an output shaft 7a, which is rotatably supported between an upper crankcase 5 and a lower crankcase 6, that is, disposed on a left side of an engine room. A magnet cover 60 is fixed to right side parts of the two crankcases 5, 6. A magnet MG is disposed between the two crankcases 5, 6 and the magnet cover 60 at a location toward a right end 7b of the crankshaft 7. An oil pump FEP for feeding lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60, and an oil pump SCP for recovering lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60.

Abstract: A dual pumping element fluid system for an engine or other system which reduces the driving power consumption by unloading one pumping element through the use of recirculation when a fluid pressure target value is achieved. A cross-over port fluid system prevents cavitation of the unloaded pump. A pressure-activated flow control valve mechanism is utilized to open and close the passageways from the secondary pump. The fluid system works in conjunction with an engine balance shaft system to control gear rattle at low speeds without adding undue gear loads at high speeds.

Abstract: An engine drive assembly includes a camshaft gear, and a first idler gear engaged with the camshaft gear. The engine drive assembly further includes a crankshaft gear engaged with the first idler gear and a second idler gear assembly engaged with the crankshaft gear. Additionally, the engine drive assembly includes a balance shaft gear engaged with the second idler gear. The crankshaft gear drives the camshaft gear via the first idler gear and the crankshaft gear drives the balance shaft gear via the second idler gear assembly.

Abstract: An engine accessory drive that has a primary drive driveable by a crankshaft of the engine is disclosed. The accessory drive includes a rotational member mounted on a drive shaft and driveable by the primary drive, the drive shaft having an axis of rotation offset from the axis of rotation of the crankshaft. The accessory drive further includes a secondary drive having a flexible continuous secondary drive member external of the engine and driveable by the rotational member, and at least one engine accessory driveable by the secondary drive. The at least one engine accessory includes at least a balance shaft.

Abstract: An engine balancer system is provided in which a balancer housing (17) disposed so as to face an oil pan beneath a crankshaft is formed by joining an upper housing (29) and a lower housing (30) via mating faces (P), and the height of the mating faces (P) is lower on a vehicle front side than on a vehicle rear side. Oil discharge holes (45a, 46) for discharging oil that is within the balancer housing (17) are formed in the mating faces (P) on the higher side of the balancer housing (17) and in the upper housing (29) above the mating faces (P) on the lower side of the balancer housing (17). This enables the position of the oil discharge hole (45a) on the lower side to be as high as possible, thereby suppressing penetration of oil into the interior of the balancer housing (17) through the oil discharge hole (45a).

Abstract: An internal combustion engine includes a crankcase, a cylinder, a piston, a crankshaft, and a piston connecting rod. A counterweight connects to the crankshaft through a counterweight connecting rod. The counterweight pivotally connects to the crankcase. The engine is constructed such that the crankshaft drives the counterweight less than 180 degrees out of phase with the motion of the piston. A center of gravity of the crankshaft is offset from the crankshaft's axis and moves out of phase with the piston by less than 180 degrees. The offset counterweight and crankshaft balance out inertial forces in the engine to reduce engine vibrations and improve engine performance.

Abstract: A dual fluid pump assembly driven by respective shafts of a dual balancing shaft assembly for an engine of an automotive vehicle. A shaft housing rotatably supports primary and secondary balancing shafts of the dual balancing shaft assembly. The shafts are coupled by a gear train for rotating the primary and secondary balance shafts in opposite directions. Each shaft includes a distal end for supporting and driving a fluid pump. A pump housing is fixedly secured to the shaft housing for enclosing the fluid pump and retaining fluid therebetween. The pumps are disposed adjacent the shaft housing and within a seal formed by the shaft housing and pump housing.

Abstract: In an engine operated machine system including a hollow support rod connected at one end to an engine through a vibration insulator, an auxiliary weight is mounted at the other end of a crankshaft for generating a centrifugal force in the same direction as an inertia force of a piston, when the piston reaches top and bottom dead centers. Thus, it is possible to bring a center of gravity of the engine closer to the position of the vibration insulator, thereby suppressing the application of the vibration from the engine to the support rod to the utmost.

Abstract: A first balancer shaft includes a shaft extension portion extending forward, to which a driven sprocket is attached. A case member includes a first bearing portion supporting the balancer shaft near its weight portions and rotational gear and a second bearing portion supporting the same near its driven sprocket. The case member includes an upper case coupled to a cylinder block and a lower case facing to the upper case, and there is provided a case extension portion extending forward at the upper case. The first bearing portion is configured of a hole formed by half-split portions of the both cases and the second bearing portion is configured of a hole formed integrally at the case extension portion.

Abstract: A balancer structure for an engine includes a first balancer shaft, a second balancer shaft, a crankshaft having a crank gear and balancer gears on the first and second balancer shafts provided parallel to the crankshaft and driven for rotation by the crank gear. The first balancer shaft is provided on one side of a normal plane including an axis of the crankshaft, and the second balancer shaft is provided on another side. On the second balancer shaft is provided a counter gear for transmitting a rotation of the crankshaft to a main shaft of a transmission mechanism.

Abstract: An idler shaft assembly for an internal combustion engine provides significant cost savings eliminates processing and assembly steps, and provides accurate orientation of components. The idler shaft assembly includes a shaft adapted for rotation about a first axis. A one-piece sprocket and gear assembly is received on the shaft. A sprocket portion of the one-piece assembly has a first diameter that cooperates with an associated drive chain that is driven by the crankshaft, and a gear portion of the one-piece assembly has a second diameter that cooperates with an associated gear of an associated balance shaft.

Abstract: Balance shaft assemblies are used in internal combustion engines to dampen primary and second order inertia forces. Known balance shaft assemblies typically require precision manufacturing and a rigid frame or housing. A balance shaft assembly (1) in accordance with this invention provides a low cost and less complex solution to engine balancing. The balance shaft assembly (1) includes an elongate housing (2) having a front end and a rear end, a balance shaft (5) which is rotatably supported between a front end bearing (6), a rear end bearing (7) and an intermediate bearing (12) in the housing (2). The housing (2) is transversely flexible relative to the balance shaft (5) to accommodate misalignment of the intermediate bearing (12) relative to the front and rear end bearings (6, 7). Consequently, the balance shaft assembly (1) can be less complicated and manufactured at a lower cost than known balance shaft assemblies.

Abstract: Cap segment surfaces (9a) and (9b) of a larger-diameter end portion (7) of a connecting rod (5) are positioned at an upper and a lower portions of a crank pin (8) and are inclined from a right upper portion of the larger-diameter end portion (7) of the connecting rod (5) to a left lower portion thereof. A cap (10) is attached by connecting rod bolts (11a) and (11b), head portion (12a) and (12b) of which are arranged vertically along the inclination direction of the cap segment surfaces (9a) and (9b). With a piston (24) existing at a bottom dead center, a weight connection portion (15a) of an upper rotary balancer (4a) is provided with a recess (13a) at a portion oriented leftwards and downwards which comes to face the head portion (12a) of the upper connecting rod bolt (11a).