engine valve train

Abstract

A valve mechanism of an engine, comprising: an intake valve and an exhaust valve of the engine; a camshaft, the camshaft is provided with an intake cam and an exhaust cam, and the intake cam and the exhaust cam are rotated by the crankshaft of the engine, thereby respectively opening and closing the intake valve and the exhaust valve; and a phase variable mechanism that changes the phase of the rotation direction of the intake cam or the exhaust cam with respect to the crankshaft. The camshaft includes: an intake camshaft provided with an intake cam; and an exhaust camshaft provided with an exhaust cam, and the intake camshaft and the exhaust camshaft are configured to be able to Relative displacement in the direction of rotation; and wherein the phase variable mechanism includes: a driven member rotated by the crankshaft; a guide member that rotates with the intake camshaft or the exhaust camshaft and can rotate relative to the driven member direction and relative displacement in the axial direction; centrifugal weight, the centrifugal weight is arranged between the driven member and the guide member; The guiding member, and due to the centrifugal force against the pushing force of the pushing member causes the centrifugal weight to move, whereby the guiding member is relatively displaced in the rotational direction and the axial direction with respect to the driven member, thereby causing the intake cam or the exhaust cam to rotate in the rotational direction The phase on is changed relative to the crankshaft.

Description

technical field [0001] The present invention relates to a valve train of a single overhead camshaft (SOHC) type engine including a phase variable mechanism for changing the rotation direction of an intake cam or an exhaust cam. The phase is varied relative to the crankshaft, enabling the valve timing of the intake and exhaust valves to be varied. Background technique [0002] In recent years, there has been provided a valve train including a valve timing variable device for changing the valve timings of the intake valve and the exhaust valve according to the operating state of the engine, etc., as described in Patent Document 1 (Japanese Patent Hei. Laid-Open No. 2013-7293) and Patent Document 2 (Japanese Patent Laid-Open No. 2010-31855). [0003] The valve trains of the engines described in Patent Documents 1 and 2 each include a camshaft phase variable mechanism for changing the phase of the rotation direction of the camshaft relative to the crankshaft so that The valve ...

AI Technical Summary

Problems solved by technology

[0004] Unfortunately, however, the camshaft phase change mechanism described in the aforementioned prior art document is applied to a double overhead camshaft (DOHC) type valve train in which one camshaft includes an intake cam and the other The shaft includes exhaust cams, and as such, this DOHC type is not suitable for SOHC type valve trains

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