JPH0415924Y2 - - Google Patents

Description

[Detailed Description of the Invention] Field of Application of the Invention The present invention relates to a hydraulic valve lash adjuster installed in a rocker arm type valve train.

BACKGROUND TECHNOLOGY In a conventional Rockscar arm type valve train, a hydraulic valve latch adjuster is attached to a cylinder of a Rockscar arm, and more precisely, the adjuster has an outer plunger that is slidably fitted into the cylinder of the Rockscar arm. Then, the bottom of the outer plunger comes into contact with the shaft end of the valve shaft.

Problems to be Solved by the Invention With this configuration, considerable effort and expense are required to process the cylinder formed in the rocker arm. However, in addition to processing problems, there are major structural problems that need to be improved. That is, when the rocker arm is tilted due to operation, a load is applied to the adjuster from an oblique direction, and surface pressure increases at the contact portion between the inner surface of the cylinder of the rocker arm and the adjuster, causing a problem of wear.

The object of the present invention is to provide a hydraulic valve lash adjuster that solves these problems.

Means for Solving the Problems In order to achieve this object, the present invention brings the open end of the plunger slidably fitted into the cylinder of the adjuster into contact with the tip of the rocker arm on a spherical surface, and the bottom of the cylinder To provide a hydraulic valve lash adjuster characterized in that a lower surface and an end of a valve shaft are brought into contact with each other through a spherical surface. These spherical contacts are made by a convex spherical surface at the tip of the rocker arm and a concave spherical surface at the open end of the plunger, and by a convex spherical surface at the axial end of the valve shaft and a concave spherical surface at the bottom of the cylinder. Alternatively, the tip of the rocker arm may be a concave sphere, and the open end of the plunger may be a convex sphere. In this way, the adjuster is placed between the rocker arm and the valve shaft, and is connected to the rocker arm and the valve shaft through spherical contact, which simplifies the structure of the rocker arm and allows the movement of the rocker arm to be transmitted smoothly and effortlessly to the valve shaft. can do.

Embodiments Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In FIG. 1, the tip of the rocker arm 1 is formed into a convex spherical surface 1a, while the open end of the plunger 2, which is slidably fitted into the cylinder 3 of the adjuster, has a concave shape that complements the convex spherical surface 1a of the rocker arm. It is formed into a spherical surface 2a, and both spherical surfaces are in tight contact with each other. A concave spherical surface 3a is formed on the bottom surface of the cylinder 3 and contacts a convex spherical surface 8a formed at the end of the valve shaft 8. The inside of the plunger constitutes a reservoir chamber 4 which is closed by the convex spherical portion 1a of the rocker arm 1, and this reservoir chamber 4 is connected to the reservoir chamber 4 via a check valve 9.
It communicates with a high pressure chamber 5 formed by the cylinder 3 and the bottom of the plunger 2. 10 is a return spring arranged between the cylinder 3 and the plunger 2. Reservoir chamber 4 is also Rotzker arm 1
It communicates with an oil supply path inside the camshaft via an oil passage 6 inside. One or more extremely shallow oil drain grooves 7 are provided at the open end of the plunger in order to drain unnecessary oil supplied to the reservoir chamber 4 to the outside.

FIG. 2 shows another embodiment of the hydraulic valve lash adjuster according to the present invention, in which the tip of the rocker arm 1 is formed into a concave spherical surface 1b, and the open end of the plunger 2 is formed into a convex spherical surface 2b. The other configurations are substantially the same as the example shown in FIG.

The hydraulic valve lash adjuster operates as follows. When the engine valve opens according to the movement of the cam, the load of the valve spring is transmitted as a reaction force to the cylinder 3 of the adjuster, generating high pressure in the high pressure chamber 5. A portion of the oil in the high pressure chamber 5 leaks from the gap between the cylinder 3 and the plunger 2, and the cylinder 3 is displaced upward with respect to the plunger 2 by that amount.

Next, when the valve closes, a relative displacement occurs between the cylinder 3 and the plunger 2 due to the action of the return spring, and the high pressure chamber 5 becomes negative pressure, causing oil to flow from the reservoir chamber 4 into the high pressure chamber 5. , oil is supplied to the reservoir chamber 4 from an oil passage 6. A part of the oil that has flowed into the reservoir chamber 4 flows out from the oil drain groove 7. Therefore, the air bubbles in the oil that are about to accumulate are discharged together, so that the high pressure chamber 5 does not suck in air.

Effects of the invention In this invention, since the adjuster is connected to the rocker arm and the valve shaft through spherical contact,
During operation of the rocker arm, the connecting portion moves freely, so that no undue force is applied. Therefore,
Mutual wear of parts can be reduced. Furthermore, since the structure of the rocker arm itself is simple, the hydraulic valve lash adjuster as a whole can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one example of a hydraulic valve lash adjuster according to the present invention, and FIG. 2 is a sectional view of another example of a hydraulic valve lash adjuster. 1...Rotzker arm, 1a... Convex spherical surface, 2
... Plunger, 2a ... Concave spherical surface, 3 ... Cylinder, 1b ... Concave spherical surface, 2b ... Convex spherical surface, 8
...Valve shaft, 8a... Convex spherical surface, 3a... Concave spherical surface.

Claims (1)

[Scope of utility model registration request] The open end of the plunger slidably fitted into the cylinder of the adjuster is in contact with the tip of the rocker arm through a spherical surface, and the lower bottom surface of the cylinder is in contact with the shaft end of the valve shaft through a spherical surface. Hydraulic valve lash adjuster.