Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: An engine valve operating system is provided in which a rocker arm that swings by following a valve operating cam abuts against an engine valve via a hydraulic tappet, a receiving member (41) receiving the hydraulic tappet (12) being slidably fitted into the rocker arm (13), the hydraulic tappet (12) being fitted into the rocker arm (13), a restricting part (29) being provided so as to face the receiving member (41) from the side opposite to the hydraulic tappet (12), and an adjustment screw (44) for adjusting a clearance between the restricting part (29) and the receiving member (41) when the engine valve is in a valve-closed state being screwed into an engine main body (5) so that its position can be adjusted back-and-forth so as to abut against the receiving member (41) when the engine valve is closed.

Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: A valve-operating system for an internal combustion engine includes cam followers which have cam abutment portions abutting against valve-operating cams provided on a camshaft and which are swingably carried in an engine body and operatively connected to engine valves biased in a closing direction by a valve spring. The cam followers are biased in a direction of abutment of the cam abutment portions against the valve-operating cams by a resilient biasing means different from the valve spring. A resilient biasing means includes a pull rod connected at one end thereof to the cam follower, and a compression coil spring interposed between the other end of the pull rod and the engine body to pull the pull rod to bias the cam follower in a direction of abutment of the cam abutment portion against the valve-operating cam. Thus, the resilient biasing means is constructed to be compact, leading to an increase in degree of freedom of the design of the structure of the valve-operating system.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: To allow both the valve lift and valve timing for an engine valve to be varied in a continuous manner, the variable valve actuating device (1) comprises a camshaft (8) rotatably supported by a fixed part of the engine and provided with a cam (7), a first rocker arm (9) pivotally supported by a fixed part of the engine, the first rocker arm being provided with a first point (12) engaging a stem of an engine valve (6), a drum (11) rotatably supported by a fixed part of the engine and at least partly surrounding the cam, a second rocker arm (10) having a first point (20) pivotally supported by the drum, a second point (21) adapted to engage the cam and a surface engaged by a second point (22) of the first rocker arm, and a control member (25, 26) for selectively turning the drum over a prescribed angular range.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: To allow both the valve lift and valve timing for an engine valve to be varied in a continuous manner, the variable valve actuating device (1) comprises a camshaft (8) rotatably supported by a fixed part of the engine and provided with a cam (7), a first rocker arm (9) pivotally supported by a fixed part of the engine, the first rocker arm being provided with a first point (12) engaging a stem of an engine valve (6), a drum (11) rotatably supported by a fixed part of the engine and at least partly surrounding the cam, a second rocker arm (10) having a first point (20) pivotally supported by the drum, a second point (21) adapted to engage the cam and a surface engaged by a second point (22) of the first rocker arm, and a control member (25, 26) for selectively turning the drum over a prescribed angular range.

Abstract: A case member mounting structure, in which a case member (5) is mounted to an engine body (2, 3, 4) by fixing an outer circumference of the case member (5) to the engine body (2, 3, 4) with a plurality of fastening means (34) to cover a power transmission mechanism, includes at least one projecting portion (40, 41) which projects from one or both of the inner wall surface of the case member (5) and the outer wall surface of the engine body (2, 3, 4) for contact with the other, and a seal member (44) applied to the contact surface at the distal end of the projecting portion (40, 41).

Abstract: In a case member mounting structure for mounting a chain case to an engine body, the chain case is fastened to the engine body by a number of bolts applied along the outer edges thereof and by bolts applied to portions in a central region thereof. The chain case has a plurality of central fastening boss portions in a central region of the inner wall surface, and bolt fastening holes are formed in the respective central fastening boss portions. An annular connection wall is formed in a projecting fashion to connect the central fastening boss portions such that the chain case is affixed to the engine body by putting the connection wall and the central fastening boss portions in abutment with the engine body. As a result, it is possible to fasten the chain case with fewer fastening bolts, enhance the rigidity of the central region of the chain case and prevent its vibrations.

Abstract: In a case member mounting structure for mounting a chain case to an engine body, the chain case is fastened to the engine body by a number of bolts applied along the outer edges thereof and by bolts applied to portions in a central region thereof. The chain case has a plurality of central fastening boss portions in a central region of the inner wall surface, and bolt fastening holes are formed in the respective central fastening boss portions. An annular connection wall is formed in a projecting fashion to connect the central fastening boss portions such that the chain case is affixed to the engine body by putting the connection wall and the central fastening boss portions in abutment with the engine body. As a result, it is possible to fasten the chain case with fewer fastening bolts, enhance the rigidity of the central region of the chain case and prevent its vibrations.

Abstract: A case member mounting structure, in which a case member (5) is mounted to an engine body (2, 3, 4) by fixing an outer circumference of the case member (5) to the engine body (2, 3, 4) with a plurality of fastening means (34) to cover a power transmission mechanism, includes at least one projecting portion (40, 41) which projects from one or both of the inner wall surface of the case member (5) and the outer wall surface of the engine body (2, 3, 4) for contact with the other, and a seal member (44) applied to the contact surface at the distal end of the projecting portion (40, 41)

Abstract: In a balance shaft for engine balancing systems for canceling an unbalance force of an engine, a journal portion of the balance shaft is provided with a recess on a side remote from the gravitational center of the counter weight, and a rib extends axially across this recess along a radial plane between full circular axial end portions of the journal portion to compensate for the reduction in the bending rigidity of the balance shaft due to the provision of the recess. The recess reduces the weight or mass of the balance shaft, and this recess does not diminish the performance of the bearing because the bearing load is essentially due to the unbalanced mass of the counter weight portion, and the recessed part of the bearing portion receives a significantly smaller part of the bearing load than the opposite side of the bearing portion. The recessing also contributes to increasing the eccentricity of the gravitational center of the associated part.