JPS632565Y2 - - Google Patents

Description

[Detailed description of the invention] This invention automatically opens the exhaust valve or intake valve slightly when starting an internal combustion engine, reduces the compression pressure in the combustion chamber, lightens the starting load, and returns to the normal rotation speed. This invention relates to an automatic starting load reducing device that controls a valve to automatically close when the load increases.

This type of device generally includes a weight that rotates integrally with the camshaft and is swung by centrifugal force, and the swinging of the weight causes the valve opening/closing tappet to move toward and away from the base circle of the cam. .

The present invention is also an automatic starting load reducing device equipped with a weight that swings due to the centrifugal force as described above, to ensure that the position of the weight during low-speed rotation from engine stop to initial engine startup and the position of the weight during normal rotation are maintained. The purpose is to simplify the mechanism and to ensure that the tappet push-up lever operates smoothly and reliably.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the structure of the present invention shown in the drawings will be described below. 1 is a camshaft, 2 is a cam, and 3 is a cam gear, and these 1 to 3 are integrally formed.
Gear 3 is adjacent to cam 2. Reference numeral 4 denotes a valve opening/closing tappet, which is arranged so that its lower surface is in contact with the cam 2.

Reference numeral 5 denotes a sickle-shaped weight, the end of which corresponds to a handle 51 is swingably attached to the side surface of the gear 3 with a shaft pin 6.

Reference numeral 7 denotes a bell-crank-shaped tappet push-up lever, which can be freely swung by a shaft pin 8 perpendicular to the shaft 1 on a flat surface 101 formed on the circumferential surface of the camshaft 1 between the cam 2 and the gear 3. installed on. One end 71 of the tappet pressing lever 7 is located on the lower surface of the tappet 4, and the other end bent portion 72 engages with a bifurcated portion 53 provided on the blade portion 52 of the sickle-shaped weight 5.

A tension coil spring 10 is stretched between the handle 51 of the sickle-shaped weight 5 and a pin 9 placed on the side of the gear 3 to draw the handle 51 toward the camshaft 1 side. Instead of the tension coil spring 10, a torsion coil spring may be provided around the weight mounting shaft 6. In short, the weight 5 is moved toward the camshaft 1 side when the engine is stopped or during low-speed rotation at the beginning of startup. There are no limitations on the structure of the spring or its mounting position as long as it acts to cause the end 71 of the tappet push-up lever 7 to protrude beyond the base circle 21 of the cam 2.

A stopper 11 is provided near the attachment point of the tappet push-up lever on the camshaft 1 to stop the lever 7 at that position when the lever end 71 has swung to a position where it protrudes outside the base circle 21. The stopper 11 in the embodiment is a step formed on the surface of the camshaft 1, but a pin may be placed thereon so that the lever 7 comes into contact with it.

A hook-shaped stopper 12 is formed at the tip of the sickle-shaped weight 5 to abut against the camshaft 1 and restrict further swinging when the weight 5 swings due to normal rotation.

The drawings all show the engine stopped, or when the engine speed is still low at the beginning of startup, and the force of the spring 10 overcomes the centrifugal force, causing the sickle-shaped weight 5 to move towards the camshaft 1.
The tappet push-up lever 7, which is pulled to the side and engaged with the bifurcated portion 53, is turned and the stopper 11
and maintain that position. At this time, the end portion 71 of the lever 7 as shown in FIGS. 3 and 4,
It protrudes outward from the cam base circle 21 by a height H.

Therefore, when the camshaft 1 rotates, the tappet 4 is pushed up by the above-mentioned height H in the compression stroke every rotation, and the valve moves away from the valve seat and the compressed gas escapes, reducing the load of the starting operation.

When the rotation of the engine increases, the sickle-shaped weight 5 is moved by the spring 1.
0, the stopper 12 swings outward around the shaft pin 6 until it hits the camshaft 1 due to the action of centrifugal force and maintains that position. At this time, the tappet push-up lever 7 is pulled by the weight 5 and turns around to the side of the cam gear 3, and its end 71 enters the same position as the cam base circle 21 or inside it.

Therefore, there is no upward force on the tappet 4, and the valve is completely closed even during the compression stroke.

Since the automatic starting load reducing device of the present invention has the above-mentioned configuration, the operating positions of the sickle-shaped weight 5 and the tappet push-up lever 7 are reliably maintained during low-speed rotation when the engine is stopped or at the initial stage of starting, thereby reducing the pressure inside the combustion chamber. Can be lowered.

Also, the weight 5 and lever 7 during normal rotation
The operating position of the tappet 4 is also maintained reliably, and there is no risk of pushing the tappet 4 up inadvertently.

Furthermore, as the camshaft 1 rotates, the tip 71 of the tappet push-up lever 7 on that shaft hits the tappet 4 and resistance is applied to the lever 7, but the fulcrum shaft 8 of the lever 7
is provided in a direction perpendicular to the camshaft 1, so that the lever 7 can swing with the shaft 8 as a fulcrum without difficulty, and the lever 7 operates smoothly and reliably.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the device of the present invention, Fig. 2 is a longitudinal sectional side view along the line shown in Fig. 1, and Fig. 3 is a front view of the camshaft rotated 90 degrees from the state shown in Fig. 1. , FIG. 4 is a longitudinal sectional side view taken along the line of FIG. 3. 1 is a cam shaft, 2 is a cam, 3 is a cam gear, 4 is a tappet, 5 is a sickle-shaped weight, 7 is a lever for pushing up the tappet, 6 and 8 are shaft pins, 10 is a spring, and 11 and 12 are stoppers.

Claims (1)

[Scope of utility model registration request] In an internal combustion engine, the rotation of the camshaft causes a cam installed on the shaft to reciprocate a tappet to open and close the intake and exhaust valves of the combustion chamber. The end of the handle of the weight is swingably attached with a shaft pin, and one end is located on the circumferential surface of the camshaft between the cam and the gear, one end is located on the lower surface of the tappet, and the other end is located on the blade of the sickle-shaped weight. A bell crank type tappet push-up lever that engages with the fork of the camshaft is swingably mounted with a shaft pin orthogonal to the camshaft, and when the engine is stopped or during low-speed rotation at the beginning of startup, the tappet side end of the above-mentioned tappet push-up lever is attached. A spring is provided between the sickle-shaped weight and the gear to urge the part to protrude from the cam base circle, and a stopper is provided on the camshaft to stop the tappet push-up lever at the tappet push-up position. An automatic starting load reduction device for an internal combustion engine in which a stopper is formed at the tip of a sickle-shaped weight to receive and regulate the swing of the weight using a camshaft.