JPS60119308A - Valve timing changing device of 4-cycle engine - Google Patents

Abstract

PURPOSE:To set two suction or exhaust valves which are opened and closed by a forked rocker arm, so as to have different open and close timing by providing a gap above one of the valves and connecting an adjusting piece to the valve. CONSTITUTION:A rocker arm 8 which is rocked by a cam 7 is formed in a fork- shape and at the top ends of the forked ends of the rocker arm 10 gap adjusting screws 10 are provided. A valve 1 has a gap 3 at the top and is connected with an adjusting piece 4. Because of having the gap 3 the lift of the valve 1 is smaller than the lift of a valve 2 for the extent of the gap and the timing also is different for that extent. As the timing of the two valves are different a high performance can be obtained from a high speed to a low speed with a good balance, and the voltex thus produced in the combustion chamber gives a favorable condition of combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve timing changing device for a four-stroke engine that opens two intake valves or two exhaust valves by pushing them down with one cam.

Some 4-cycle engines are equipped with two intake valves and two exhaust valves to make the intake passage and exhaust passage large (1). In this case, the two intake valves or the two exhaust valves are opened and closed by one cam, and the valve opening and closing timings are the same.

This invention uses one cam to open and close two intake valves or two exhaust valves, and by changing the opening and closing timing of the two intake valves or two exhaust valves, high engine performance can be generated. Embodiments of the present invention shown in the drawings will be described below.

A gap 3 is provided at the upper end of one of the two intake valves or two exhaust valves 1 and 2, and the adjustment piece 4
Concatenate. The adjustment piece 4 is designed to be able to slide by a gap of 30 minutes. Then, on one intake valve or exhaust valve 1,
The length of the gap 3 plus the length of the adjustment piece 4 is made to match the length of the other intake valve or exhaust valve 2. The two intake or exhaust valves 1 and 2 are each biased upward by a spring 5 to close them. Camshaft 6 is cam 7
is provided and rotates in conjunction with the crankshaft f ^ λ. The rocker arm 8 has its base end pivotably supported on a rocker shaft 9, and its distal end is split into two parts. and the upper end of the other intake valve or exhaust valve 2 (~). Then, by the rotation of the cam 7,
Push the rocker arm 8 to open the two intake valves or exhaust valves 1
, 2 are pushed down against a spring 5 to open them.

When the rocker arm 8 is pushed down by the rotation of the cam 7, the other intake valve or exhaust valve 2 is immediately opened by a pressing force. One intake valve or exhaust valve 1 is
First, the adjusting piece 4 is pushed down, the gap 3 disappears, and the adjusting piece 4 hits one of the intake valves or exhaust valves l, and then one of the intake valves or the exhaust valve 1 is opened. Therefore, the opening/closing timing of one intake valve or exhaust valve 1 is shown in Figure 3 (1).
The opening/closing timing of the other intake valve or exhaust valve 2 is as shown by the line (1) in FIG.
Each can have different opening and closing timings. With a 4-stroke engine, the opening and closing timing is short (3) at low speeds, resulting in a combustion state. Higher output can be obtained with fewer problems such as noise, and higher output can be obtained by lengthening the opening/closing timing and increasing the intake amount at high speeds, so the timing of one intake valve or exhaust valve 1 at low speeds By adjusting the timing of the other intake valve or exhaust valve to a high speed in accordance with this, high, well-balanced performance can be obtained from low speed to high speed.

In addition, the two intake valves 1.2 have different opening and closing timings, which creates directionality in the intake air flow, creating a vortex in the entire combustion chamber, resulting in good combustion, which also improves output. do. Furthermore, one intake valve or exhaust valve 1 and the adjustment piece 4
Since it slides in the three gaps, there is less noise and fewer stress problems.

As explained above, the present invention allows one cam to push down a rocker arm with a bifurcated tip to push down and open two intake valves or two exhaust valves. A gap is provided at the top of the exhaust valve to fully connect the adjustment pieces, and the opening and closing timings of the two intake valves or the two exhaust valves are made different, so that balanced high performance can be obtained from high speed to low speed. The result is a good vortex flow in the combustion chamber (4)

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partial side view, FIG. 2 is a vertical front view, and FIG. 3 is a diagram showing valve timing. 1.2...Intake valve or exhaust valve, 3...Gap, 4...
・Tone i1 piece, 7...cam, 8...rocker arm. Applicant's agent Kiyoshi Inomata #/Zumachima 60-119308 (3)

Claims (1)

[Claims] When opening two intake valves or two exhaust valves by pushing down a rocker arm with a forked tip using one cam, adjust by creating a gap at the top of one of the intake valves or exhaust valves. A valve timing changing device for a four-stroke engine, characterized in that the opening and closing timings of two intake valves or two exhaust valves are made different by connecting the pieces.