Abstract: In an internal combustion engine, a gasket is disposed between joining surfaces of a cylinder block and a cylinder head, and a heat radiation rib that extends in a cylinder axis direction is formed on the cylinder block or the cylinder head. In such an internal combustion engine, the gasket includes: a portion to be sandwiched that is sandwiched between the joining surfaces; and an extending portion that protrudes toward an outside from the portion to be sandwiched as viewed in a cylinder axis direction.

Abstract: In an internal combustion engine that includes a cylinder block and a cylinder head, and has a cam chain chamber on a side of the cylinder block, a beam member that traverses the cam chain chamber is disposed in the cam chain chamber.

Abstract: In an internal combustion engine that includes a cylinder block and a cylinder head, and has a cam chain chamber on a side of the cylinder block, a beam member that traverses the cam chain chamber is disposed in the cam chain chamber.

Abstract: In an internal combustion engine, a gasket is disposed between joining surfaces of a cylinder block and a cylinder head, and a heat radiation rib that extends in a cylinder axis direction is formed on the cylinder block or the cylinder head. In such an internal combustion engine, the gasket includes: a portion to be sandwiched that is sandwiched between the joining surfaces; and an extending portion that protrudes toward an outside from the portion to be sandwiched as viewed in a cylinder axis direction.

Abstract: In an internal combustion engine that includes a cylinder block and a cylinder head, and has a cam chain chamber on a side of the cylinder block, a beam member that traverses the cam chain chamber is disposed in the cam chain chamber.

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: To provide a power transmission system for a vehicle wherein a starter is simplified, the number of component parts is small, and a reduction in cost can be contrived. Thus, an excellent operationality at the time of starting is achieved. A power transmission system for a vehicle, including a clutch and a fluid transmission through both of which the rotational torque of a crankshaft of an internal combustion engine is transmitted to a load-side transmission mechanism, wherein the clutch and the fluid transmission are both provided on one side of the crankshaft, and a drive force of a starter is directly inputted to the other side of the crankshaft.

Abstract: A balancer driven gear 11 mof an engine, for the transfer of rotation of the crankshaft 4 to a balancer shaft 8, is made up of a gear member 30, a bush member 20 and elastic members 41 and 45 interposed therebetween. Wrong assembly such as reverse assembly is prevented by the following configuration. The bush member 20 has a boss portion 21 fixed to the balancer shaft 8, and a plurality of outward dowels 23a, 23b, . . . projecting radially outward from the outer periphery of the boss portion 21. The gear member 30 is disposed coaxially with the bush member 20. The gear member 30 has an annular portion 31 with gear teeth on the outer periphery thereof and a plurality of inward dowels 33a, 33b, . . . projecting radially inward from the inner periphery of the annular portion 31. Elastic members 41 and 45 are disposed between the outward dowels 23a . . . on the bush member 20 and the inward dowels 33a . . . on the gear member 30.

Abstract: An internal combustion engine includes a split crankcase with spaced-apart journal walls. Each journal wall has a bearing hole formed therein. The engine also includes rotary bearings for supporting rotary movement of a crankshaft. A backlash-absorbing mechanism is situated proximate a first one of the rotary bearings, for cushioning radial movement of an outer bearing race. Axial movement-restraining structure is also provided adjacent the outer race, for limiting axial movement thereof. The axial movement-restraining structure may include an engaging groove provided in an inner circumferential surface of the outer race, and a restraining clamp member operatively attached to a surface of the crankcase. The restraining clamp member may include a hook portion which engages with the engaging groove of the outer race. The axial movement-restraining structure allows at least one of the crankshaft support bearings to be a roller bearing or a needle bearing, instead of a ball bearing.

Abstract: A connection structure between a plastic gear and a shaft permits easy phase matching relative to a device mounted on the shaft, and easy meshing of a gear provided on the shaft with another gear. The connection structure includes a plastic gear, a shaft, and a set plate. The plastic gear has a geometric recess which receives the correspondingly-shaped set plate therein. The set plate includes a central shaped opening. The shaft is provided with a mating extension extending from a first end, and which fits within the shaped opening. The mating extension is formed such that the plastic gear may be mounted thereon in a first position wherein the plastic gear is not positioned to interact with a mating gear, and the plastic gear can be slidably moved thereon to a second position such that the plastic gear is positioned to interact with the mating gear.

Abstract: A bearing structure of a crankshaft in an internal combustion engine supports a crankshaft on a crankcase with rolling bearings includes a play absorbing device for absorbing the play in the radial direction generated between an outer race of the rolling bearing and a bearing hole of the crankcase. The play absorbing device includes a push plug which pushes an outer race of the ball bearing in the direction perpendicular to an axis of the crankshaft. The push plug is arranged in parallel to the crankshaft between the cylinder and the crankshaft. The outer race of the ball bearing is resiliently biased toward a side of the bearing hole of the crankcase which receives an explosion pressure. As a result, the generation of a hitting sound which is attributed to the above-mentioned “play” can be largely reduced even with respect to an internal combustion engine with a high explosion pressure.

Abstract: An internal combustion engine includes a split crankcase with spaced-apart journal walls. Each journal wall has a bearing hole formed therein. The engine also includes rotary bearings for supporting rotary movement of a crankshaft. A backlash-absorbing mechanism is situated proximate a first one of the rotary bearings, for cushioning radial movement of an outer bearing race. Axial movement-restraining structure is also provided adjacent the outer race, for limiting axial movement thereof. The axial movement-restraining structure may include an engaging groove provided in an inner circumferential surface of the outer race, and a restraining clamp member operatively attached to a surface of the crankcase. The restraining clamp member may include a hook portion which engages with the engaging groove of the outer race. The axial movement-restraining structure allows at least one of the crankshshaft support bearings to be a roller bearing or a needle bearing, instead of a ball bearing.

Abstract: To provide a power transmission system for a vehicle wherein a starter is simplified, the number of component parts is small, and a reduction in cost can be contrived. Thus, an excellent operationality at the time of starting is achieved. A power transmission system for a vehicle, including a clutch and a fluid transmission through both of which the rotational torque of a crankshaft of an internal combustion engine is transmitted to a load-side transmission mechanism, wherein the clutch and the fluid transmission are both provided on one side of the crankshaft, and a drive force of a starter is directly inputted to the other side of the crankshaft.

Abstract: A bearing structure of a crankshaft in an internal combustion engine supports a crankshaft on a crankcase with rolling bearings includes a play absorbing device for absorbing the play in the radial direction generated between an outer race of the rolling bearing and a bearing hole of the crankcase. The play absorbing device includes a push plug which pushes an outer race of the ball bearing in the direction perpendicular to an axis of the crankshaft. The push plug is arranged in parallel to the crankshaft between the cylinder and the crankshaft. The outer race of the ball bearing is resiliently biased toward a side of the bearing hole of the crankcase which receives an explosion pressure. As a result, the generation of a hitting sound which is attributed to the above-mentioned “play” can be largely reduced even with respect to an internal combustion engine with a high explosion pressure.

Abstract: A connection structure between a plastic gear and a shaft permits easy phase matching relative to a device mounted on the shaft, and easy meshing of a gear provided on the shaft with another gear. The connection structure includes a plastic gear, a shaft, and a set plate. The plastic gear has a geometric recess which receives the correspondingly-shaped set plate therein. The set plate includes a central shaped opening. The shaft is provided with a mating extension extending from a first end, and which fits within the shaped opening. The mating extension is formed such that the plastic gear may be mounted thereon in a first position wherein the plastic gear is not positioned to interact with a mating gear, and the plastic gear can be slidably moved thereon to a second position such that the plastic gear is positioned to interact with the mating gear.

Abstract: A transmitting system for a small-sized vehicle having an engine and a multi-stage transmission comprising a crankshaft of the engine, an input shaft of the multi-stage transmission, a shifting clutch and a primary reducing device. The input shaft is disposed in parallel to the crankshaft and the crankshaft and input shaft are connected to each other through a fluid transmitting means. The fluid transmitting means including a pump impeller leading to the engine, and a turbine impeller leading to the multi-stage transmission. The fluid transmitting means and the shifting clutch are mounted on the crankshaft of the engine and connected in series to each other. One of the fluid transmitting means and the shifting clutch is connected to the crankshaft, and the other is connected to the input shaft of the multi-stage transmission through the primary reducing device.

Abstract: In a transmitting system for a small-sized vehicle in which a crankshaft of an engine and an input shaft of a multi-stage transmission are connected to each other through a fluid transmitting device, a shifting clutch is interposed between the crankshaft of the engine and the multi-stage transmission in a series relation to the fluid transmitting device. A lock-up clutch is interposed between a pump impeller and a turbine impeller of the fluid transmitting device. Thus, when the multi-stage transmission is to be shifted, the shifting operation can be conducted lightly, in spite of a creep phenomenon of the fluid transmitting device, by bringing the shifting clutch into an OFF state. Moreover, during cruising of the vehicle, the slipping of the fluid transmitting device can be inhibited by the OFF state of the lock-up clutch to enhance the transmitting efficiency.

Abstract: In a transmitting system for a small-sized vehicle in which a crankshaft of an engine and an input shaft of a multi-stage transmission are connected to each other through a fluid transmitting device, the fluid transmitting device including a pump impeller leading to the engine, and a turbine impeller leading to the transmission, a shifting clutch is interposed between the crankshaft of the engine and the multi-stage transmission in a series relation to the fluid transmitting device. Thus, a creep phenomenon of the fluid transmitting device can be eliminated, and the shifting operation of the transmission can be conducted lightly, by bringing the shifting clutch into its OFF state.

Abstract: In a transmitting system for a small-sized vehicle in which a crankshaft of an engine and an input shaft of a multi-stage transmission are connected to each other through a fluid transmitting device, the fluid transmitting device and a shifting clutch are mounted on the crankshaft. One of the fluid transmitting device and the shifting clutch is connected to the crankshaft, while the other is connected to the input shaft of the multi-stage transmission through a primary reducing device. Provided in the crankshaft are an upstream supply oil passage connected to an oil pump, a downstream supply oil passage connected to portions to be lubricated of the engine, a flow-in bore which permits the upstream supply oil passage to communicate with the inside of the fluid transmitting device, and a flow-out bore which permits the inside of the fluid transmitting device to communicate with the downstream supply oil passage.

Abstract: In a transmitting system for a small-sized vehicle in which a crankshaft of an engine and an input shaft of a multi-stage transmission are connected to each other through a fluid transmitting device, a shifting clutch is interposed between the crankshaft of the engine and the multi-stage transmission in a series relation to the fluid transmitting device. A lock-up clutch is interposed between a pump impeller and a turbine impeller of the fluid transmitting device. Thus, when the multi-stage transmission is to be shifted, the shifting operation can be conducted lightly, in spite of a creep phenomenon of the fluid transmitting device, by bringing the shifting clutch into an OFF state. Moreover, during cruising of the vehicle, the slipping of the fluid transmitting device can be inhibited by the OFF state of the lock-up clutch to enhance the transmitting efficiency.