JPS6137777Y2 - - Google Patents

Description

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

This type of device generally includes a weight that rotates integrally with the camshaft and is swung by centrifugal force, and the movement of the weight causes the tab to move toward and away from the base circle of the cam.

The purpose of this project is to create an automatic starting load reducing device equipped with a weight that can be swung by the centrifugal force mentioned above, and to accurately maintain the position of the weight during low-speed rotation at the initial stage of startup and the position of the weight during normal rotation. shall be. Another purpose is to simplify the maintenance mechanism.

The structure of the present invention will be explained below with reference to the drawings. 1 is the camshaft, 2 is the cam, and 3 is the gear, and the three are 1 to 3.
rotates as a unit. 4 is an exhaust valve or an intake valve, 5 is a valve seat, and 6 is a tab for opening and closing the valve 4, which is arranged so that its lower surface is in contact with the cam 2.

Reference numeral 7 denotes a sickle-shaped weight, which is attached to the side surface of the cam gear 3 by a shaft pin 8 near the base of a portion 71 corresponding to a blade.

From the end of the portion 72 corresponding to the handle of the sickle-shaped weight 7,
A tabet push-up arm 9 that reaches the bottom surface of the tabet 6 extends out.

A tension coil spring 11 is stretched between the tip of the blade portion 71 of the sickle-shaped weight 7 and a pin 10 placed on the side of the cam gear 3. Instead of the spring 11, a torsion coil spring may be provided around the weight mounting shaft 8. In other words, during low-speed rotation at the beginning of engine startup, the weight 7 is moved toward the center and the push-up arm 9 is moved toward the cam 2. There are no limitations on the type of spring or the mounting position as long as it acts to project outward from the base circle 21 of the spring.

The above structure is substantially the same as a conventional starting load self-reducing device (see, for example, Japanese Utility Model Application Publication No. 49-63337).

The present invention is an automatic starting load reducing device having the above-mentioned structure. A stopper 12 is provided for regulating the swing angle of the sickle-shaped weight 7, which the blade portion 71 and the handle portion 72 come into contact with during normal rotation.

Figures 1 and 2 show the state in which the rotation is still slow at the initial stage of startup, and the force of the spring 11 overcomes the centrifugal force, and the weight 7 is drawn toward the center, and its blade 71
The inner edge of the ring contacts the stopper 12 to maintain its position. At this time, the push-up arm 9 integrated with the weight 7 protrudes outward from the cam base circle 21 by a gap g.

Therefore, each time the camshaft 1 rotates, the tab 6 is pushed up by the above gap g during the compression stroke.
As shown in FIG. 1, the valve 4 separates from the valve seat 5 and the compressed gas escapes, reducing the load of the starting operation.

As the engine speeds up, the sickle-shaped weight 7 swings outward around the shaft pin 8 due to centrifugal force against the spring 11, as shown in FIG. It maintains its position. At this time, the push-up arm 9 completely enters the same position as the cam base circle 21 or inside it.

Therefore, the pushing up action of the tab 6 is eliminated, and the valve 4 is completely closed during the compression stroke.

When the engine is stopped, the weight 7 is moved to the first position by the force of the spring 11.
Return to the position shown in Figure 2.

In this case, as described above, the swing angle regulating stopper 12 of the weight 7 is located in the approximately V-shaped space S formed between the blade part 71 and the handle part 72 of the sickle-shaped weight 7, and is attached to the side surface of the cam gear 3. With the simple configuration of just providing the engine, the swing position of the weight 7, that is, the position of the arm 9 that pushes up the tab 6 during low-speed rotation at the initial stage of engine startup, can be kept constant, and the pressure in the combustion chamber can be reliably reduced.

In addition, the swing position of the weight 7 under normal operating conditions is also kept constant by the common stopper 12, and there is no risk that the weight 7 will swing inadvertently and its push-up arm 9 will act on the tab 6. This is effective as an improvement to automatic starting load reduction devices.

[Brief explanation of the drawing]

FIG. 1 is a front view of the proposed device, FIG. 2 is a side view thereof, and FIG. 3 is a side view of the device rotating at a normal speed. 1 is a camshaft, 2 is a cam, 3 is a cam gear, 4 is a valve, 5 is a valve seat, 6 is a tabet, 7 is a sickle-shaped weight, 7
1 is a blade portion, 72 is a handle portion, 8 is a shaft pin, 9 is a tab push-up arm, 11 is a spring, 12 is a swing angle regulating stopper, S is a substantially V-shaped space, and g is a gap.

Claims (1)

[Scope of utility model registration request] The base of the blade of the sickle-shaped weight is attached to the side of the cam gear, which is integrated with the camshaft that is connected to the rotating cam that reciprocates the tab that opens and closes either the intake or exhaust valve of the internal combustion engine. It is attached with a shaft pin, and a tabet push-up arm that reaches the bottom surface of the tabet extends from the end of the handle of the weight, and the hook is shaped like a sickle so that the push-up arm protrudes outside the cam base circle during low-speed rotation at the beginning of engine startup. In an automatic starting load reducing device in which a spring is provided between a weight and a cam gear, a low-speed During rotation, the blade part
Also, an automatic starting load reduction device for an internal combustion engine is provided with a stopper for regulating the swing angle of a sickle-shaped weight, which the handle comes into contact with during normal rotation.