Valve operating device for engine

Abstract

A valve gear of an engine is constituted so that a rocker arm 63 having a cam abutting part 65 abutting on a valve system cam 69 and interlocked and connected so as to apply valve opening directional force to the engine valve 19 energized in the valve closing direction by a valve spring 24, is rotatably connected with one end part of a first link arm 61 rotatably supported by a fixing position of an engine body and the other end part of a second link arm 62 rotatably supported by a displaceable movable shaft 68a; and the rocker arm 63 is energized in the direction for allowing the cam abutting part 65 to abut on the valve system cam 69 by a rocker arm energizing spring 54 separate from the valve spring 24. This ensures follow-up ability of the opening / closing operations and enables a reduction in the size of the system, while allowing the lift amount of the engine valve to vary continuously. It is also possible to improve the accuracy with which the lift amount is controlled when the engine valve is to be slightly opened.

Description

technical field [0001] The present invention relates to a valve train for an engine, which has a variable lift mechanism for continuously changing the lift amount of an engine valve as an intake valve or an exhaust valve. Background technique [0002] In order to continuously change the lift of the engine valves, Patent Document 1 discloses a valve train that has a valve abutting portion that abuts against the engine valve on one end side of the rocker arm, and has a valve abutting portion on the other end of the rocker arm. One end of a push rod is fitted to one end, and a link mechanism is provided between the other end of the push rod and the valve driving cam. [0003] However, in the valve train disclosed in Patent Document 1, it is necessary to ensure a large space between the valve train cam and the rocker arm for arranging the link mechanism and the push rod, which increases the size of the valve train. And because the driving force from the valve driving cam is tra...

AI Technical Summary

Problems solved by technology

[0007] However, in the valve train of the above aspect, when the rocker arm drives the engine valve in the valve opening direction and is urged in the valve closing direction, the cam abutting portion of the rocker arm abuts against the valve driving cam by the action of the valve spring. , but in the state where the engine valve is closed, the elastic force of the valve spring does not act on the rocker arm, and the cam abutment part of the rocker arm is away from the valve driving cam, which may lead to a decrease in the control accuracy of the valve lift amount when the engine valve is slightly opened

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