JPS60164609A - Spark advance device for valve on-off timing of four-cycle engine - Google Patents

Abstract

PURPOSE:To control the timing of valve opening or closing according to an engine speed, by installing an intermediate gear whose rotational center axis is shiftable centering around a crankshaft, while driving a cam pulley via this intermediate gear. CONSTITUTION:An intermediate shaft 3 is installed at the position between a crankshaft 1 and a cam shaft 10, while this intermediate shaft 3 is shifted by a pressure rod 5 operated through hydraulic pressure varying according to an engine speed, and the turning center of an intermediate gear to be installed in the intermediate shaft 3 moves centering around the crankshaft 1. With this constitution, the phase of the intermediate gear varies against the crankshaft 1 so that opening or closing timing of a valve is controlled to be adjusted to an optimum value according to the engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulp opening/closing timing advance device for an l-cycle engine.

In an L-cycle engine, a camshaft is rotated in synchronization with the crankshaft, and the cam on the camshaft swings a rocker arm to open the umbrella-shaped intake or exhaust valve by pushing it down against a valve spring. It looks like this. Therefore, the opening and closing timing of the valve is determined by the shape of the cam. When the engine speed increases, there is a delay in the flow of gas such as intake air, and the output decreases. Therefore, by setting the cam shape to a low-speed type or a high-speed type, it is possible to distinguish between a low-speed type engine and a high-speed type engine. It is characterized.

In view of this, this invention advances the valve opening/closing timing as the engine speed increases, improving the ability to obtain high output even at low speeds as well as high output even at high speeds. Embodiments of the present invention shown in the drawings will be described below.

A trap intermediate shaft 3 is provided on one side of the engine crankshaft so as to be movable around the crankshaft with a long hole. The crankshaft/and intermediate shaft 3 are
Interlock using gears with the same number of teeth. The intermediate shaft 3 is
It is configured to be able to move along the elongated hole 2 by pushing it against a spring 6 with a pressing rod 3. The pressing rod j is connected to the engine so that lubricating oil from an oil pump whose discharge pressure increases as the engine speed increases is injected into the cylinder tank and pushed out by hydraulic pressure. The intermediate shaft 3 is
Timing pulley j and timing belt 9 interlock camshaft io. The camshaft lO is the cam l
The rocker arm 1 is swung by the rotation of /, and the umbrella-shaped pulp 13 for intake or exhaust is pushed down against the pulp spring and opened. The change in the distance between the intermediate shaft 3 and the camshaft IO is determined by the belt tensioner l.
Absorb by Hiroshi.

The crankshaft rotates the intermediate shaft 3 through the gear lIK, and also rotates the camshaft IO through the timing pulley and the timing belt 9. The cam of the camshaft 10 is
The rocker arm/J is swung by rotation, and the pulp/3 is pushed down and opened. As the rotation of the engine increases, the oil pressure in the cylinder 7 increases, and the pressing rod S pushes up the intermediate shaft 3 along the elongated hole against the spring 6. This changes the engagement point of the pair of Gyada,
The rotation of the camshaft IO advances by the amount of change,
The opening/closing timing of the pulp 13 is advanced. In this way, the delay in gas flow at high speeds is compensated for by the advance angle, making it possible to generate high output.

As explained above, this invention has an intermediate shaft movable around the crankshaft at -111 of the crankshaft, in which the umbrella-shaped pulp is pushed down and opened by the rotation of the cam of the camshaft. The crankshaft and the intermediate shaft are interlocked by a gear, the intermediate shaft and the camshaft are interlocked, and the intermediate shaft is moved as the engine speed increases.The meshing point of the pair of gears can be adjusted by moving the intermediate shaft. As the speed increases, the opening and closing timing of the pulp can be advanced accordingly, and the gas flow can be matched to the rotation, making it possible to increase high-speed output. In this way, the engine can be kept busy to provide high output from low speeds to high speeds. In addition, the gap between the pulp and the rocker arm can be kept constant, so there is no need to worry about noise generation.

[Brief explanation of drawings]

The figure is a front view showing one embodiment of the present invention. /...Crankshaft, 3...Intermediate shaft, D...Gear, 10...Camshaft, //...Cam, 13...Pulp. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] The umbrella-shaped valve is pushed down and opened by the rotation of the cam of the camshaft, and an intermediate shaft that can be moved around the crankshaft is provided on one side of the crankshaft, and the crankshaft and the intermediate shaft are connected by gears. A pulp opening/closing timing advance device for an l-cycle engine, characterized in that an intermediate shaft and a camshaft are interlocked, and the intermediate shaft is moved as the rotation of the engine increases.