Abstract: In a variable valve mechanism, during switching from a disconnected state to a connected state, the switch arm being displaced in a return direction comes in sliding contact with a pin end surface of the switch pin, and presses the pin end surface toward the disconnected position to push back the switch pin. At a sliding contact start time, the switch arm sliding contacts a portion of the pin end surface on a return direction side with respect to an idle-swing-side edge. At least during a period from a 10% position time to a sliding contact end time, a position of a pressed center relative to the pin end surface shifts toward the return direction side without stopping as the switch arm is displaced toward the return direction relative to a main arm, so that the sliding contact ends without stopping of the pressed center at a return-side edge.

Abstract: A variable valve mechanism of an internal combustion engine includes a camshaft having a general shaft part and a cam part arranged next to each other in an axial direction, an input arm that swings when pressed by the cam part, an output arm that is swingably mounted and that drives a valve when swinging, and a switch device that switches the variable valve mechanism between a coupled state where the input arm and the output arm are coupled to swing together and an uncoupled state. The output arm has a great height so that clearance between the output arm and the general shaft part is 3 mm or less when the variable valve mechanism is in the coupled state and the valve is closed. If the output arm bounces in the uncoupled state, the output arm comes into contact with the general shaft part through the clearance.

Abstract: In a variable valve mechanism, during switching from a disconnected state to a connected state, the switch arm being displaced in a return direction comes in sliding contact with a pin end surface of the switch pin, and presses the pin end surface toward the disconnected position to push back the switch pin. At a sliding contact start time, the switch arm sliding contacts a portion of the pin end surface on a return direction side with respect to an idle-swing-side edge. At least during a period from a 10% position time to a sliding contact end time, a position of a pressed center relative to the pin end surface shifts toward the return direction side without stopping as the switch arm is displaced toward the return direction relative to a main arm, so that the sliding contact ends without stopping of the pressed center at a return-side edge.

Abstract: A variable valve mechanism of an internal combustion engine includes a plurality of swing members and a variable device that displaces a control shaft to displace a plurality of slider gears of the swing members at a time, thereby changing valve lifts of the plurality of swing members at a time by meshing of helical splines. The swing members include a first swing member for a predetermined cylinder of a plurality of cylinders and a second swing member for a cylinder other than the predetermined cylinder, and a helix angle of the helical splines varies between the first and the second swing members. The variable device displaces the control shaft to a predetermined normal position to perform a normal operation, and displaces the control shaft to a predetermined cylinder cutoff position to perform a cylinder cutoff operation in which the second swing member does not drive a valve.

Abstract: A variable valve mechanism of an internal combustion engine includes a camshaft having a general shaft part and a cam part arranged next to each other in an axial direction, an input arm that swings when pressed by the cam part, an output arm that is swingably mounted and that drives a valve when swinging, and a switch device that switches the variable valve mechanism between a coupled state where the input arm and the output arm are coupled to swing together and an uncoupled state. The output arm has a great height so that clearance between the output arm and the general shaft part is 3 mm or less when the variable valve mechanism is in the coupled state and the valve is closed. If the output arm bounces in the uncoupled state, the output arm comes into contact with the general shaft part through the clearance.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine, which includes a rocker arm that is driven by a cam so as to swing to drive a valve, a switching pin that is attached to the rocker arm so as to be shifted between a first position and a second position, a shift device that shifts the switching pin from the first position to the second position, and a return spring that returns the switching pin. In the variable valve mechanism, a drive state of the valve is switched by shifting the switching pin, the rocker arm is formed to have such a dimension that one end of the switching pin is exposed while projecting outward from the rocker arm, and the return spring is externally fitted to the one end of the switching pin so as to be exposed outside the rocker arm.

Abstract: A variable valve mechanism of an internal combustion engine includes a plurality of swing members and a variable device that displaces a control shaft to displace a plurality of slider gears of the swing members at a time, thereby changing valve lifts of the plurality of swing members at a time by meshing of helical splines. The swing members include a first swing member for a predetermined cylinder of a plurality of cylinders and a second swing member for a cylinder other than the predetermined cylinder, and a helix angle of the helical splines varies between the first and the second swing members. The variable device displaces the control shaft to a predetermined normal position to perform a normal operation, and displaces the control shaft to a predetermined cylinder cutoff position to perform a cylinder cutoff operation in which the second swing member does not drive a valve.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine, which includes a rocker arm that is driven by a cam so as to swing to drive a valve, a switching pin that is attached to the rocker arm so as to be shifted between a first position and a second position, a shift device that shifts the switching pin from the first position to the second position, and a return spring that returns the switching pin. In the variable valve mechanism, a drive state of the valve is switched by shifting the switching pin, the rocker arm is formed to have such a dimension that one end of the switching pin is exposed while projecting outward from the rocker arm, and the return spring is externally fitted to the one end of the switching pin so as to be exposed outside the rocker arm.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine which includes a main arm that is capable of swinging and that drives a valve when swinging, a first sub arm that is provided on one side in the lateral direction of the main arm and that swings when driven by a first cam, a second sub arm that is provided on the other side in the lateral direction of the main arm and that swings when driven by a second cam, and a switch device that performs switching between a first coupled state where only the first sub arm of the first and second sub arms is coupled to the main arm, and a second coupled state where only the second sub arm of the first and second sub arms is coupled to the main arm.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine, which includes a main arm having at a rear end thereof a supported portion that is continuously supported swingably by a support member without floating upward, a sub arm which has a tip end to which a roller contacting a cam is rotatably attached, in which a center of the roller is located rearward of the pressing portion and forward of a swing center of the supported portion, which has a rear end that is swingably supported with respect to the main arm by a support pin, and in which a center of the support pin is located rearward of the center of the roller and forward of the swing center of the supported portion, and a switch pin that is inserted in a central portion of the roller.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine which includes a main arm that is capable of swinging and that drives a valve when swinging, a first sub arm that is provided on one side in the lateral direction of the main arm and that swings when driven by a first cam, a second sub arm that is provided on the other side in the lateral direction of the main arm and that swings when driven by a second cam, and a switch device that performs switching between a first coupled state where only the first sub arm of the first and second sub arms is coupled to the main arm, and a second coupled state where only the second sub arm of the first and second sub arms is coupled to the main arm.

Abstract: The present invention provides a variable valve mechanism of an internal combustion engine, which includes a main arm having at a rear end thereof a supported portion that is continuously supported swingably by a support member without floating upward, a sub arm which has a tip end to which a roller contacting a cam is rotatably attached, in which a center of the roller is located rearward of the pressing portion and forward of a swing center of the supported portion, which has a rear end that is swingably supported with respect to the main arm by a support pin, and in which a center of the support pin is located rearward of the center of the roller and forward of the swing center of the supported portion, and a switch pin that is inserted in a central portion of the roller.