Variable valve mechanism of internal combustion engine

摘要

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.

主权项

1. A variable valve mechanism of an internal combustion engine, comprising:
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 from the second position to the first position, wherein 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 backward and outward from a back end of 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; a push-out member that makes contact with the cam is attached to the rocker arm, wherein the push-out member is pushed out toward a rotation center side of the cam from the rocker arm when the switching pin is shifted from one of the first position and the second position to the other position, and the push-out member is retracted into the rocker arm when the switching pin is shifted from the other position to the one position, wherein, at a time of retraction when the push-out member is retracted, a normal state is established, in which the valve is closed in a base circle section where a base circle of the cam acts and the valve is opened in a nose section where a nose of the cam acts, wherein, at a time of push-out when the push-out member is pushed out, a constantly-opened state is established, in which the valve is opened in both the base circle section and the nose section; a retracting spring that biases the push-out member in such a direction that the push-out member retracts, wherein, at the time of retraction, a gap is formed between the base circle and the push-out member, and a gap is formed between the nose and the push-out member.