Abstract: An object is to provide a bolt fastening structure which is resistant to loosening even in an environment with vibration. A fastening structure 100 according to the invention of the present application is configured such that a male screw 10 having a thread section 11 with a thread ridge 11a and a thread groove 11b, and a female screw 20 forming a recess 20 in a first member 300 serving as a fastening target, the female screw 20 having a threaded section 21 formed in the recess 20 and engaged with the thread section 11, are in a fastened state. In the fastened state, a tip portion 12 forming a leading end of the male screw 10 is in point contact with a bottom surface 23a of the recess 20.

Abstract: An exhaust system structure of an internal combustion engine, includes an exhaust manifold which is configured to be connected to a cylinder of the internal combustion engine, an exhaust pipe which is provided on a downstream side of an exhaust flow from the exhaust manifold, a connection member including a flange portion which connects the exhaust pipe and the exhaust manifold to each other and a boss portion which is provided integrally with the flange portion and is fixed to a portion of an outer circumferential surface of the exhaust pipe, a sensor which is attached to the boss portion and is configured to detect components of the exhaust, and a purification device which is connected to a downstream end of the exhaust pipe and is disposed on a side opposite to the boss portion with respect to the exhaust pipe.

Abstract: A connection member for connecting an exhaust manifold and an exhaust pipe of an internal combustion engine, includes a flange portion, a boss portion and an attachment portion. The flange portion has a plate shape with an opening configured to be fixed to the exhaust pipe in a state where the opening communicates with the exhaust pipe. The boss portion is provided to bulge from the flange portion on an outside of the opening in a radial direction of the opening, is configured so that a sensor configured to detect components of the exhaust is attached to the boss portion, and is configured to be fixed to a portion of an outer circumferential surface of the exhaust pipe. The attachment portion protrudes from the flange portion and is configured so that a protection member which covers the exhaust pipe is attached to the attachment portion.

Abstract: A cam structure driving a tappet having a crowning on a top face and connected to a base end section of an intake or exhaust valve of an engine, includes: a camshaft rotating in synchronization with a crankshaft of the engine; a cam lobe mounted on the camshaft, and including: a base cam including: a base circular section having a mounting hole for the camshaft; and a valve lift section having a cut-out section in a tip end portion; and a roller provided in the cut-out section and having a cylindrical section with a constant diameter. A center section in a width direction of the base cam makes contact with the tappet at a position deviated from a center of the top face of the tappet, and the cylindrical section makes contact with the center of the top face of the tappet.

Abstract: A cam structure driving a tappet having a crowning on a top face and connected to a base end section of an intake or exhaust valve of an engine, includes: a camshaft rotating in synchronization with a crankshaft of the engine; a cam lobe mounted on the camshaft, and including: a base cam including: a base circular section having a mounting hole for the camshaft; and a valve lift section having a cut-out section in a tip end portion; and a roller provided in the cut-out section and having a cylindrical section with a constant diameter. A center section in a width direction of the base cam makes contact with the tappet at a position deviated from a center of the top face of the tappet, and the cylindrical section makes contact with the center of the top face of the tappet.

Abstract: A valve mechanism for an internal combustion engine includes a first rocker arm (4) connected to an intake or exhaust valve and supported on a rocker shaft (3a), a second rocker arm (5) supported on the rocker shaft for being rotationally driven by a cam, a cylinder (10) formed on one of the first and second rocker arms (4, 5) and a first piston (11) provided in the cylinder, a contacting projection (4a) projecting on the other one of the first and second rocker arms, a return spring (12) for biasing the first piston in a direction in which the first piston contacts with the contacting projection, and a second piston (14) for displacing the first piston to a position at which the first piston does not contact with the contacting projection. The two pistons extend in parallel to each other when the first piston is at a non-contacting position.

Abstract: The invention relates to a valve mechanism for an internal combustion engine, and it is an object of the invention to make it possible to carry out changeover of the driving mode rapidly and with certainty.

Abstract: A variable valve device includes a camshaft which is rotatably provided in an internal combustion engine while having a cam, a rocker shaft which is arranged next to the camshaft, a valve which is driven by the cam, a cam follower rocker which is rotatably provided in the rocker shaft, and is rocked by following the cam, a valve drive rocker which is rotatably provided in the rocker shaft next to the cam follower rocker, and drives the valve, and a switching portion which be able to switch the valve drive rocker between a drive state and a non-drive state. Either a body of the cam follower rocker or a body of the valve drive rocker is made of an iron-based metal material, and the other body is made of a material different from the iron-based metal material, heat treatment being not required in the different material.

Abstract: A variable valve device for an internal combustion engine includes an internal combustion engine body having a plurality of cylinders, a variable valve mechanism which is provided in the body and is switchable between at least two modes with oil pressure, a mode switching oil control valve which switches the variable valve mechanism to each mode, and a camshaft-driven mode switching oil pump which supplies an oil pressure for switching driving to the variable valve mechanism according to the switching of the mode switching oil control valve. The mode switching oil control valve is, along with the mode switching oil pump, provided in an outer wall surface of the body.

Abstract: A variable valve device for an internal combustion engine comprises a first switching oil passage which is formed along an axial direction in one of a rocker shafts, the first rocker arm being switched to the first mode by applying oil pressure to a first rocker arm through the first switching oil passage, and a second switching oil passage which is formed along an axial direction in the other rocker shaft, a second rocker arm being switched to the first mode by applying oil pressure to the second rocker arm through the second switching oil passage. The first switching oil passage and the second switching oil passage are formed in a ladder shape in which the first switching oil passage and the second switching oil passage communicate via a plurality of relay oil passages.

Abstract: A variable valve device for an internal combustion engine includes an internal combustion engine body having a plurality of cylinders, a variable valve mechanism which is provided in the body and is switchable between at least two modes with oil pressure, a mode switching oil control valve which switches the variable valve mechanism to each mode, and a camshaft-driven mode switching oil pump which supplies an oil pressure for switching driving to the variable valve mechanism according to the switching of the mode switching oil control valve. The mode switching oil control valve is, along with the mode switching oil pump, provided in an outer wall surface of the body.

Abstract: A variable valve device for an internal combustion engine comprises a first switching oil passage which is formed along an axial direction in one of a rocker shafts, the first rocker arm being switched to the first mode by applying oil pressure to a first rocker arm through the first switching oil passage, and a second switching oil passage which is formed along an axial direction in the other rocker shaft, a second rocker arm being switched to the first mode by applying oil pressure to the second rocker arm through the second switching oil passage. The first switching oil passage and the second switching oil passage are formed in a ladder shape in which the first switching oil passage and the second switching oil passage communicate via a plurality of relay oil passages.

Abstract: A variable valve device includes a camshaft which is rotatably provided in an internal combustion engine while having a cam, a rocker shaft which is arranged next to the camshaft, a valve which is driven by the cam, a cam follower rocker which is rotatably provided in the rocker shaft, and is rocked by following the cam, a valve drive rocker which is rotatably provided in the rocker shaft next to the cam follower rocker, and drives the valve, and a switching portion which be able to switch the valve drive rocker between a drive state and a non-drive state. Either a body of the cam follower rocker or a body of the valve drive rocker is made of an iron-based metal material, and the other body is made of a material different from the iron-based metal material, heat treatment being not required in the different material.