Abstract: The invention provides a cylinder head gasket installed by being sandwiched between a cylinder block and a cylinder head of an internal combustion engine. The cylinder head gasket has bore holes each having a circular plane at positions which are lapped over a combustion chamber in said cylinder block, and surface pressure generation portions constructed by three-dimensional shapes surrounding said bore holes at positions which are lapped over partition walls between the combustion chamber in said cylinder block and a water jacket portion. The surface pressure generation portions are arranged at fixed positions in a thickness direction of said partition wall and are arranged closer to the combustion chamber side or the water jacket portion side than the fixed positions in the thickness direction of said partition wall partly on a circumference around the bore holes. Therefore, bore deformation can be reduced.

Abstract: The purpose of the invention is to make it possible to perform pressurized leak tests on open loop chain case-side oil seal beads. The purpose is achieved with a cylinder head gasket, which is fitted between the cylinder block and the cylinder head and seals the three-surface sealing region obtained by combining the cylinder block, the cylinder head and the chain case, and in which an open-loop chain case-side oil seal bead that is open toward the chain case is provided in the chain case-side end of the gasket. The cylinder head gasket is characterized in that a closed-loop leak test bead is provided in the cylinder head gasket along a chain case-side oil seal bead and a leak test pressure supply path for supplying leak test pressure to the space enclosed by the leak test bead is provided.

Abstract: The invention provides a cylinder head gasket installed by being sandwiched between a cylinder block and a cylinder head of an internal combustion engine. The cylinder head gasket has bore holes each having a circular plane at positions which are lapped over a combustion chamber in said cylinder block, and surface pressure generation portions constructed by three-dimensional shapes surrounding said bore holes at positions which are lapped over partition walls between the combustion chamber in said cylinder block and a water jacket portion. The surface pressure generation portions are arranged at fixed positions in a thickness direction of said partition wall and are arranged closer to the combustion chamber side or the water jacket portion side than the fixed positions in the thickness direction of said partition wall partly on a circumference around the bore holes. Therefore, bore deformation can be reduced.

Abstract: The purpose of the invention is to make it possible to perform pressurized leak tests on open loop chain case-side oil seal beads. The purpose is achieved with a cylinder head gasket, which is fitted between the cylinder block and the cylinder head and seals the three-surface sealing region obtained by combining the cylinder block, the cylinder head and the chain case, and in which an open-loop chain case-side oil seal bead that is open toward the chain case is provided in the chain case-side end of the gasket. The cylinder head gasket is characterized in that a closed-loop leak test bead is provided in the cylinder head gasket along a chain case-side oil seal bead and a leak test pressure supply path for supplying leak test pressure to the space enclosed by the leak test bead is provided.

Abstract: The present invention provides a sealing bead in which linearly acting surface pressures are generated at its portions which does not directly contribute to generating the linearly acting surface pressures in the conventional sealing bead, thereby enhancing the efficiency for generating linearly acting surface pressures with respect to a displacement amount of height of the sealing bead. A peripheral portion of a sealing bead between a bent position and an opening edge is bent up or down so as to form a pre-determined degree of an angle with respect to a corresponding flange surface. With this structure, linearly acting surface pressures are generated at the opening edge that, in the conventional bead, does not directly contribute to generating linearly acting surface pressures.

Abstract: A metal gasket including a thin metal plate (1) provided with beads (3) and step members (4) each of which includes a coating layer having a property of high load resistance. The step member (4) is attached to the bead along a convex ridge of the bead (3), thereby increasing a quantity of compression of the bead (3), to cause a great surface pressure and decreasing an amplitude of stress in the bead (3) to improve a property of fatigue resistance of the bead (3). Also, the step member (4) is attached to the bead within a concave surface of the bead, thereby restraining the quantity of compression of the bead (3) to improve the property of fatigue resistance of the bead (3) and assuring the surface pressure on the concave surface of the bead by the step member (4).

Abstract: The arm on which the idler pulley is supported as well as the tensioner which biases the arm to tension a timing belt or the like are both mounted on a common base plate. The plate is pivotally supported on the engine block and selectively secureable in a desired position. A stopper mechanism which can be used to temporarily disable the biasing and damping functions of the tensioner enables automatic tension setting.