A method for producing a spray channel on a shaft tube, whereby a completed shaft tube can output fluid from within the shaft tube to outside of the shaft tube, the method may include introducing at least one through-opening with a diameter D.sub.1≥1.5 mm into the shaft tube and arranging at least one additional element in or on the at least one through-opening such that the spray channel is at least partly formed by the at least one additional element.

Systems and methods for intermittent supply of lubricating oil to a tip of a rocker arm assembly. In one embodiment, a lubricating oil may be selectively to a tip of a rocker arm via oil channels aligned only during opening of a valve coupled to the tip.

Systems and methods for an engine are provided. The engine includes a straight rocker shaft passing through each of a first rocker arm and a second rocker arm, the first rocker arm being shaped differently from the second rocker arm.

A camshaft cover, a camshaft assembly, and a double-cylinder engine are provided. The camshaft cover has an integral structure, and includes a first shaft cover portion, a second shaft cover portion, a first connecting portion and a second connecting portion. The first connecting portion and the second connecting portion are connected between the first shaft cover portion and the second shaft cover portion, and spaced apart axially.

An engine includes a cylinder head including a first oil path and a second oil path. The cylinder head includes a valve gear including a first support and a second support that support a rocker shaft. The first support includes, on its outer surface, a first constriction located at an inlet of a connection-switching third oil path and connected to the first oil path, and a second constriction connected to the second oil path. The second support includes, on its outer surface, a third constriction connected to the first oil path, and a fourth constriction located at an inlet of a lubrication fourth oil path and connected to the second oil path.

A lubricating oil supply structure includes: a shaft; a bearing supporting the shaft and having an oil supply port, through which lubricating oil is supplied to between the shaft and the bearing, and an oil introduction port, through which the lubricating oil is introduced; a first oil passage, connected to the oil supply port, distributing the lubricating oil from an oil pump toward the oil supply port; a second oil passage, connected to the oil introduction port, supplying the lubricating oil introduced through the oil introduction port to a supply destination; a connection oil passage, formed by a gap between the bearing and the shaft, connecting between the first oil passage and the second oil passage, and a throttle portion, formed on a part of the connection oil passage, suppressing a flow of the lubricating oil from the oil supply port toward the oil introduction port.

An electrically-actuated camshaft phaser used in an internal combustion engine including a camshaft sprocket, configured to receive rotational input from a crankshaft, that includes a sprocket ring gear having a plurality of radially-inwardly facing gear teeth and a radially extending sprocket side; a camshaft plate that includes a camshaft ring gear having a plurality of radially-inwardly facing gear teeth and a radially extending camshaft side; a plurality of planetary gears having radially-outwardly facing gear teeth, each gear with a first radial gear face and a second radial gear face, wherein the planetary gears engage the sprocket ring gear, the camshaft ring gear, or both the sprocket ring gear and the camshaft ring gear; and one or more fluid escapement channels formed in at least one of the camshaft sprocket, the camshaft plate, the first radial gear face, or the second radial gear face.

An engine oil passage structure for an engine contributing to downsizing the engine and achieving protection of an oil passage against external forces is provided. Provided is an oil passage structure for an engine installed in a small vehicle, the engine including an engine body formed of a crankcase and a cylinder block and a cylinder head stacked inclined vehicle frontward on the crankcase, the crankcase, the cylinder block, and the cylinder head being integrally fastened. The oil passage structure includes, near a bent part formed by a case front wall of the crankcase and a cylinder front wall of the cylinder block forming a valley part by an obtuse angle, a right-left direction oil passage extending in a right-left direction along the valley part.

Methods and systems are provided for a valve bridge of an internal combustion engine. In one example, a valve bridge comprises a first arm, a longitudinally opposing second arm, and one or more interior walls forming a passage extending laterally through at least a portion of the valve bridge, the passage disposed between the first arm and second arm and forming a first main opening and an opposing, second main opening. A central support structure is disposed within the passage and is formed by the one or more interior walls.

An improved, lightweight gear drive having a rim gear mounted on a shaft, the shaft formed of one or more shaft segments, each of the shaft segments supporting a segregated arc. The segregated arcs forming a circumferential portion of a bearing surface of the shaft.