Valve operating apparatus for internal combustion engine

Abstract

Provided is a valve operating apparatus for an internal combustion engine that, with respect to a configuration including urging means that urges a transfer member that transfers an acting force of a cam to a valve, can facilitate manufacture of a support portion of the urging means and suppress an increase in the mass of the internal combustion engine. A first rocker arm is provided that is interposed between a main cam and a valve and that transfers an acting force of the main cam to the valve. A lost motion mechanism is provided that urges the first rocker arm in one direction. A holding member is provided that holds the lost motion mechanism. The lost motion mechanism is attached to a spark plug tube through the holding member.

1 . A valve operating apparatus for an internal combustion engine, comprising:
 a transfer member that is interposed between a cam and a valve, and transfers an acting force of the cam to the valve;   urging means that urges the transfer member in one direction; and   a holding member that holds the urging means,   wherein the urging means is attached to a spark plug tube through the holding member, and   wherein the holding member is supported by the spark plug tube and is not supported by a cylinder head of the internal combustion engine.   
     
     
         2 . The valve operating apparatus for an internal combustion engine according to  claim 1 ,
 wherein the transfer member includes a first rocker arm that rocks in synchrony with rotation of the cam, and   wherein the urging means is means that urges the first rocker arm towards the cam.   
     
     
         3 . The valve operating apparatus for an internal combustion engine according to  claim 2 ,
 wherein the holding member is attached to the spark plug tube in a condition in which the holding member is rotatable in a circumferential direction of the spark plug tube,   wherein the valve operating apparatus for an internal combustion engine further comprises:   an engagement groove that is formed in one of the urging means and the first rocker arm at a contact portion between the urging means and the first rocker arm; and   a projecting portion that is formed in the other of the urging means and the first rocker arm at the contact portion and that engages with the engagement groove.   
     
     
         4 . The valve operating apparatus for an internal combustion engine according to  claim 2 ,
 wherein the transfer member further includes a second rocker arm that is capable of pushing and moving the valve,   wherein the valve operating apparatus for an internal combustion engine further comprises a switching mechanism capable of switching between a connected state in which the first rocker arm and the second rocker arm are in connection and a non-connected state in which the connection is released, and   wherein the urging means is a lost motion mechanism that urges the first rocker arm so as to maintain a state in which the first rocker arm contacts the cam.   
     
     
         5 . The valve operating apparatus for an internal combustion engine according to  claim 1 ,
 wherein the urging means is a lash adjuster that has a function of expanding and contracting so as to make a tappet clearance zero and that is disposed so as to support a fulcrum of the transfer member.   
     
     
         6 . The valve operating apparatus for an internal combustion engine according to  claim 1 ,
 wherein the holding member includes a holding portion that covers a trunk portion of the urging means from outside, and an attachment portion that is attached to the spark plug tube.   
     
     
         7 . The valve operating apparatus for an internal combustion engine according to  claim 6 ,
 wherein a cross-sectional shape of the holding portion is an enlarged shape of a cross-sectional shape of the urging means.   
     
     
         8 . The valve operating apparatus for an internal combustion engine according to  claim 1 ,
 wherein an end portion on an opposite side to an end portion that contacts the transfer member in the urging is received and stopped by a base member to which the spark plug tube is fixed.   
     
     
         9 . A valve operating apparatus for an internal combustion engine, comprising:
 a transfer member that is interposed between a cam and a valve, and transfers an acting force of the cam to the valve;   an urging element that urges the transfer member in one direction; and   a holding member that holds the urging element,   wherein the urging element is attached to a spark plug tube through the holding member, and   wherein the holding member is supported by the spark plug tube and is not supported by a cylinder head of the internal combustion engine.