JPH0341041Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic valve lash adjuster for an internal combustion engine.

Conventionally, in this type of valve lash adjuster, air has entered the high pressure chamber for some reason, which has impaired the rigidity of the adjuster and caused loud hammering noise from the valve train. In addition to the air entering the adjuster directly from the oil circuit as air bubbles in the oil, the air enters the cylinder by swinging the fitting gap in the circumferential direction while the adjuster slides up and down. Outside air may directly enter through the gap between the inner cylinder and the outer circumference of the outer plunger, or the gap between the bore of the cylinder head and the outer circumference of the cylinder body.

Therefore, an object of the present invention is to provide a labyrinth on the sliding surface between the outer plunger and the cylinder inner cylinder and between the bore of the cylinder head and the cylinder body so that the outside air can be easily removed from the valve. The purpose is to prevent it from entering the inside of the shaft adjuster.

An embodiment of the hydraulic valve lash adjuster of the present invention will now be described with reference to the accompanying drawings.

A cylinder body 5 fitted into the cylinder head 1 is in contact with the cam 2 and is provided with an inner lid 6 that is integral with the cylinder body 5 and an inner cylinder tube 7 that is integral with the inner lid 6. An outer plunger is slidably fitted into the cylinder inner tube 7, and an inner plunger 10 is further fitted into the outer plunger 9. An O-ring 8 is provided on the outer plunger 9. The oil introduction chamber 17 in the cylinder body 5 communicates with the oil circuit 4 of the cylinder head via an oil supply recess 15 and an oil supply hole 16 formed in the cylinder body 5.

A reservoir chamber 18 formed inside the inner plunger 10 communicates with an oil introduction chamber 17 via an oil supply port 19 provided on the top wall of the cylinder body 5, and communicates with the oil introduction chamber 17 via a check valve 14 between the outer plunger 9 and the inner plunger. A high pressure chamber 25 formed between
It communicates with A return spring 13 is provided between the outer plunger 9 and the inner plunger 10 within the high pressure chamber 25 .

According to the present invention, a group or labyrinth 20 is provided on the sliding surface between the outer periphery of the outer plunger 9 and the cylinder inner cylinder 7, and a labyrinth 20 is provided on the sliding surface between the outer periphery of the cylinder body 5 and the cylinder head 1. Groups or labyrinths 21 and 22 are also provided.

Although the drawings show that the labyrinth 20 is provided on the outer periphery of the outer plunger 9, it may be provided on the inner periphery of the cylinder inner tube 7. Furthermore, instead of providing the labyrinths 21 and 22 on the outer periphery of the cylinder body 5, they may be provided on the inner periphery of the cylinder head 1.

The hydraulic valve lash adjuster operates as follows. When the valve 3 of the internal combustion engine is opened according to the movement of the cam 2, the load of a valve spring (not shown) provided below the outer plunger 9 is transmitted to the outer plunger 9, and high pressure is generated in the high pressure chamber 25. do. A part of the oil in this high pressure chamber 25 leaks from the gap between the inner plunger 10 and the outer plunger 9,
is slightly displaced (displaced upward in the drawing) with respect to the inner plunger 10.

Next, when valve 3 closes, return spring 1
3, a restoring force is applied to the outer plunger 9 and it is displaced (displaced downward in the drawing), and the high pressure chamber 2
5 becomes lower pressure than the reservoir chamber 18, the check valve 14 opens and the pressure in the high pressure chamber 2 is lower than that in the reservoir chamber 18.
5, oil is supplied to the reservoir chamber 18 from the oil introduction chamber 17 through the oil supply port 19, and oil is further supplied to the oil introduction chamber 17 from the oil circuit 4 of the cylinder head through the oil supply hole 16. is supplied.

While the valve brush adjuster performs the above-described operation, the outer plunger 9 slides and swings slightly in the gap between the outer plunger 9 and the cylinder inner tube 7, and the air that enters through this gap is removed. However, there are cases where the oil tries to enter the oil introduction chamber 17. However, by providing the labyrinth 20 as in the present invention, the air is forced out again due to the pressure difference between the inside of the cylinder body 5 and the outside air. Similarly, air may enter from outside into the gap between the outer periphery of the cylinder body 5 and the cylinder head 1, but by providing the labyrinths 21 and 22 as in the present invention, the air is forced out again. .

[Brief explanation of the drawing]

The accompanying drawing is a sectional view showing the hydraulic valve lash adjuster of the present invention. 9... Outer plunger, 10... Inner plunger, 20, 21, 22... Labyrinth.

Claims (1)

[Claims for Utility Model Registration] A cylinder body 5 slidably fitted into a cylinder bore of a cylinder head 1 of an internal combustion engine, and a cylinder inner tube 7 formed integrally with the cylinder body 5 slidably fitted. Outer plunger 9
and an inner plunger 10 slidably fitted into the outer plunger 9, and a high pressure chamber 2 is provided between the outer plunger 9 and the inner plunger 10.
5 is formed inside the cylinder body 5, and an oil introduction chamber 17 surrounded by the cylinder body 5, the outer plunger 9, and the inner plunger 10.
On the other hand, a reservoir chamber 18 is formed in a portion surrounded by the cylinder body 5 and the inner periphery of the inner plunger 10, and an oil circuit 4 provided in the cylinder head 1 and an oil reservoir chamber 18 are formed on the peripheral wall of the cylinder body 5. An oil supply hole 16 that communicates with the introduction chamber 17 is provided, an oil supply port 19 that communicates the oil introduction chamber 17 and the reservoir chamber 18 is provided, and the inner plunger 10
In the hydraulic valve lash adjuster, a check valve 14 is provided at the bottom of the tank to allow flow only from the reservoir chamber 18 to the high pressure chamber 25. A labyrinth 20 is provided, and labyrinths 21 and 22 are provided on the sliding surface between the cylinder head 1 and the cylinder body 5,
A hydraulic valve lash adjuster characterized in that labyrinths 20, 21, and 22 are configured to be substantially always on sliding surfaces.