Abstract: A cover of an internal combustion engine includes a cover body to be mounted to a crankcase of the internal combustion engine. The cover body includes a through hole, a protruding part, and a plurality of first recessed grooves. The through hole is to support a shaft rotatably. The protruding part is provided above the through hole in an upward direction of the internal combustion engine and protrudes toward an inside of the cover body facing the crankcase. The protruding part includes a first upper part and a first lower part in the upward direction on an inner surface of the protruding part facing the crankcase. The plurality of first recessed grooves extend radially from the through hole so as to connect the upper part and the lower part of the protruding part.

Abstract: A cover of an internal combustion engine includes a cover body to be mounted to a crankcase of the internal combustion engine. The cover body includes a through hole, a protruding part, and a plurality of first recessed grooves. The through hole is to support a shaft rotatably. The protruding part is provided above the through hole in an upward direction of the internal combustion engine and protrudes toward an inside of the cover body facing the crankcase. The protruding part includes a first upper part and a first lower part in the upward direction on an inner surface of the protruding part facing the crankcase. The plurality of first recessed grooves extend radially from the through hole so as to connect the upper part and the lower part of the protruding part.

Abstract: A chain tensioner device includes a main arm, tensioner lifter, and a sub-arm. The main arm is pivotally supported by a first shaft. The main arm slidably contacts an endless chain to apply a tension to the endless chain. The tensioner lifter includes a housing, a plunger, and a spring. The plunger is slidably held by the housing. The spring is to press the plunger such that the plunger projects from the housing. The sub-arm is disposed between the main arm and the tensioner lifter. The sub-arm is pivotally supported by a second shaft to transmit a biasing force applied by the plunger of the tensioner lifter to the main arm. A moving direction of the plunger is substantially orthogonal to a direction of a tangent at a contact portion between the plunger and the sub-arm when an elongation of the endless chain reaches a maximum elongation.

Abstract: A chain tensioner device having a first slide surface of a main arm pivotably supported at an upper end thereof, and a second slide surface of a sub-arm pivotably supported at a lower end thereof. The first and second slide surfaces slidably abut against each other. When the main arm is biased toward a timing chain via the sub-arm by a biasing force of a plunger of a tensioner lifter, a stroke of the main arm is increased with respect to a stroke of the plunger.

Abstract: A cover structure, for an internal combustion engine, that can inhibit lubricating oil from remaining at a protrusion portion is provided. The cover structure for an engine includes a chain case that covers a timing train mechanism, and a timing train chamber is formed between the chain case and the engine main body. The chain case includes bolt insertion holes provided at side marginal portions and directed toward the engine main body, a variable-valve boss portion and a second-oil-path boss portion that protrude from a wall portion toward the engine main body and form a recessed portion where lubricating oil for lubricating the timing train mechanism remains, and a first rib that is protruding from the wall portion toward the engine main body and provided upper than at least the recessed portion.

Abstract: A chain tensioner device having a first slide surface of a main arm pivotably supported at an upper end thereof, and a second slide surface of a sub-arm pivotably supported at a lower end thereof. The first and second slide surfaces slidably abut against each other. When the main arm is biased toward a timing chain via the sub-arm by a biasing force of a plunger of a tensioner lifter, a stroke of the main arm is increased with respect to a stroke of the plunger.

Abstract: A chain tensioner device having a first slide surface of a main arm pivotably supported at an upper end thereof, and a second slide surface of a sub-arm pivotably supported at a lower end thereof. The first and second slide surfaces slidably abut against each other. When the main arm is biased toward a timing chain via the sub-arm by a biasing force of a plunger of a tensioner lifter, a stroke of the main arm is increased with respect to a stroke of the plunger.

Abstract: A chain tensioner device includes a main arm, tensioner lifter, and a sub-arm. The main arm is pivotally supported by a first shaft. The main arm slidably contacts an endless chain to apply a tension to the endless chain. The tensioner lifter includes a housing, a plunger, and a spring. The plunger is slidably held by the housing. The spring is to press the plunger such that the plunger projects from the housing. The sub-arm is disposed between the main arm and the tensioner lifter. The sub-arm is pivotally supported by a second shaft to transmit a biasing force applied by the plunger of the tensioner lifter to the main arm. A moving direction of the plunger is substantially orthogonal to a direction of a tangent at a contact portion between the plunger and the sub-arm when an elongation of the endless chain reaches a maximum elongation.

Abstract: An oil pump in which pulsation vibration due to the dynamic pressure on the discharge port side can be attenuated. In an oil pump for transporting fluid from a suction port to a discharge port by the rotation of a rotor mounted in a pump casing, a resonator configured from an introduction path and a chamber is formed with respect to a discharge flow channel that communicates with the discharge port in the flow direction of the discharge flow channel. A channel in a direction different to the flow direction of the discharge flow channel is communicatingly formed in the vicinity of the resonator.

Abstract: A chain tensioner device having a first slide surface of a main arm pivotably supported at an upper end thereof, and a second slide surface of a sub-arm pivotably supported at a lower end thereof. The first and second slide surfaces slidably abut against each other. When the main arm is biased toward a timing chain via the sub-arm by a biasing force of a plunger of a tensioner lifter, a stroke of the main arm is increased with respect to a stroke of the plunger.

Abstract: An oil pump in which pulsation vibration due to the dynamic pressure on the discharge port side can be attenuated. In an oil pump for transporting fluid from a suction port to a discharge port by the rotation of a rotor mounted in a pump casing, a resonator configured from an introduction path and a chamber is formed with respect to a discharge flow channel that communicates with the discharge port in the flow direction of the discharge flow channel. A channel in a direction different to the flow direction of the discharge flow channel is communicatingly formed in the vicinity of the resonator.