| 摘要 |
PURPOSE: A method is provided to allow for ease of replacement of tappet shim by forming a gap between the cam and the bucket contacting each other. CONSTITUTION: A valve drive system includes a cam(10) where a cam shaft(20) having an oil passage(21) is fixed; and a bucket(30) for transmitting the rotation of the cam to a valve(40). The cam has a predetermined space formed inside thereof, and a piston unit is accommodated into the space of the cam. The piston unit slides toward the upper portion of the cam during the replacement of a tappet shim(60), to thereby form a predetermined gap between the base circle of the cam and the tappet shim and allow for ease of replacement of the tappet shim. The piston unit includes a cylinder(11); a plunger(12) for compressing the fluid in the cylinder and transmitting a pressure; a check ball(16) contacting a check ball sheet(12a) of the plunger so as to prevent a discharge of oil; a spring(15) interposed between the check ball and the cylinder; a plunger boss(13) arranged beneath the plunger; and an oil transfer line(17) for transferring the oil in the oil passage.
|
