JPH0544411A - Hydraulic position adjusting device - Google Patents

Abstract

PURPOSE:To warrant sure action of a valve gear system with respect to a hydraulic position adjusting device used in the valve gear system of an internal combustion engine by providing a separator capable of supplying work oil wherein air is not mixed to its high pressure chamber. CONSTITUTION:Work oil supply passages 41a, 42c formed no that they penetrate through both sides of a main body 41 and a plunger 42 and revolving flow of work oil is caused in the inner space of the plunger 42 are provided to a hydraulic position adjusting device wherein a high pressure chamber is formed with the main body 41 and the plunger 42 wherein an opening is provided at the lower part. Further, the inner space of the plunger 42 is halved to the side of the opening and the side of the work oil supply passage 42c, and a separator 48 wherein, at least, the part 48c on the upper side of the work oil supply passage is in a cone shape and a hole is formed in the part 48b on the lower side of the work oil supply passage is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic position adjusting device provided to reduce valve lash in a valve train of an internal combustion engine to zero.

[0002]

2. Description of the Related Art Since each member of a valve train of an internal combustion engine thermally expands in accordance with the amount of heat generated from the combustion chamber, the valve train of the internal combustion engine absorbs this thermal expansion amount and constantly operates the valve. A position adjustment device is needed to keep the lash at zero.

Normally, hydraulic pressure is used for such a position adjusting device, and it is known as a hydraulic valve lash adjuster used for an OHC type internal combustion engine or a hydraulic valve lifter used for an OHV type internal combustion engine. ..

The above-mentioned hydraulic valve lash adjuster is described in Japanese Utility Model Laid-Open No. 60-82506.
This is provided between the push rod and the cam that come into contact with the rocker arm, and absorbs thermal expansion of all members of the valve train during this period.

For this reason, the above-mentioned hydraulic valve lash adjuster has a bottomed tubular main body whose bottom portion abuts on the cam, and an upper portion which abuts on the push rod, and which is a hollow body slidably fitted in the main body. And a cylindrical plunger, and a high-pressure chamber is formed by the main body and the lower portion of the plunger.

Further, the plunger is constantly biased upward by a spring provided in the high pressure chamber, and an opening for supplying hydraulic oil from the internal space of the plunger to the high pressure chamber is provided at the lower part of the plunger. A check valve is provided in the opening to prevent backflow of the hydraulic oil. Engine oil is usually used as this hydraulic oil.

Since the above-mentioned hydraulic valve lash adjuster is constructed as described above, when the valve train member thermally expands, the hydraulic oil in the high pressure chamber escapes through the sliding surface between the main body and the plunger to shrink. When the amount of thermal expansion of the valve train member decreases, the plunger is pushed up by the spring in the high pressure chamber, and at the same time the hydraulic oil flows into the high pressure chamber through the opening and the check valve to stretch the plunger. In either case, the vertical movement caused by the cam can be reliably transmitted to the intake valve and the exhaust valve.

However, when air is mixed in the hydraulic oil supplied from the internal space of the plunger to the high pressure chamber when the hydraulic valve lash adjuster extends, an air layer is formed in the upper portion of the high pressure chamber. Since the air layer is easily compressed, the vertical movement of the cam cannot be accurately transmitted to the intake valve and the exhaust valve.

Therefore, a cylindrical separator surrounding the opening to the high pressure chamber is provided in the internal space of the hydraulic valve lash adjuster described above. This tubular separator penetrates both side surfaces of the plunger and the main body, and extends beyond a passage for supplying hydraulic oil to the internal space of the plunger,
A hole that communicates the inside and outside of the tubular separator is formed at a position below the passage on the side surface.

[0010]

In the hydraulic valve lash adjuster described above, the hydraulic oil is taken into the cylindrical separator through the hole, so that the hydraulic oil in the cylindrical separator has a relatively large amount of air. There are few things.
However, since air mixed in a granular form still exists in the hydraulic oil, an air layer is eventually formed in the upper part of the high pressure chamber, which causes the above-mentioned problem.

Accordingly, it is an object of the present invention to provide a hydraulic position adjusting device having a separator capable of supplying hydraulic oil containing no air to a high pressure chamber.

[0012]

In order to achieve the above-mentioned object, a hydraulic position adjusting device according to the present invention includes a main body having a side surface and a bottom surface, and slidably fitted in the main body.
A hollow plunger having a high-pressure chamber defined by its lower portion and the main body, elastic means for urging the plunger in a direction in which the high-pressure chamber expands, and hydraulic oil from the internal space of the plunger to the high-pressure chamber. An opening provided with a valve that allows only the flow of the oil, and a hydraulic oil supply passage that penetrates both side surfaces of the main body and the plunger and is formed so that a swirl flow of the hydraulic oil is generated in the internal space of the plunger. ,
The internal space of the plunger is divided into the opening side and the hydraulic oil supply passage side, and at least a portion above the hydraulic oil supply passage is a conical shape that is substantially concentric with the internal space of the plunger and protrudes upward. And a separator having a hole that connects the opening side and the hydraulic oil supply passage side with each other, is provided in a portion below the hydraulic oil supply passage.

[0013]

With the above-described structure, the hydraulic oil supplied into the plunger swirls in the plunger, and the granular air mixed in the hydraulic oil has a force toward the center of the swirling flow due to the difference in specific gravity. To work. Since a convex cone-shaped separator is provided at the center in the upper side, the granular air is pushed upward along the separator.

As a result, air can be completely removed from the working oil flowing into the separator by the holes provided in the lower part of the working oil supply passage of the separator, and the working oil supplied to the high pressure chamber is Since air is not mixed, no air layer is formed in the high pressure chamber.

[0015]

FIG. 1 is an overall sectional view of a first embodiment of a hydraulic position adjusting device according to the present invention. In the figure, 1 is an intake valve (or exhaust valve), 2 is a spring for urging the intake valve 1 to a closed position, 4 is a hydraulic position adjusting device buried in a cylinder head 5, and the rocker arm 3 has one end. Part is intake valve 1
, The roller 3a provided at the center contacts the cam 6, and the hemispherical recess provided at the other end contacts the upper part of the plunger 42 of the hydraulic position adjusting device 4 to form a fulcrum. ..

The hydraulic position adjusting device 4 of the present embodiment absorbs thermal expansion of the valve operating member by moving the fulcrum of the rocker arm 3 up and down, and a cylindrical body 41 having a bottom portion, A plunger 42, which is slidably fitted in the main body 41 and has a hollow interior, is provided with an operating oil discharge passage 42a provided at an upper portion of the plunger 42.
Irrespective of the angular position of, the hydraulic oil discharge hole 3b formed on the upper side of the hemispherical recess is always in communication.

A high pressure chamber 43 is formed by the main body 41 and the plunger 42, and a spring 4 for urging the plunger 42 upward through a concave support 44 is formed in the high pressure chamber 43.
5 are provided. Further, the opening 4 formed in the lower portion of the plunger 42 for communicating the internal space thereof with the high pressure chamber 43.
2b is closed by a ball valve 47 which is urged upward by a spring 46 provided in the recess of the support 44.

The internal space of the plunger 42 is composed of an upper conical portion and a lower cylindrical portion, and the tip of this conical portion communicates with the hydraulic oil discharge passage 42a. An enlarged view of the internal space of the plunger 42 is shown in FIG.

In the figure, the hydraulic oil supply passages 41a and 42c to the inner space of the plunger 42 are slantingly upward on both side surfaces of the main body 41 and the plunger 42 and near the boundary with the conical portion of the cylindrical portion of the inner space. It penetrates and is offset with respect to the center of the interior space, as shown in FIG. 3, which is a cross-sectional view of FIG. An annular groove is formed on the outer side surface of the plunger 42 so that the hydraulic oil supply passages 41a and 42c are always in communication with each other with respect to the vertical movement of the plunger 42.

Further, in the inner space of the plunger 42, a portion 48a fitted into the cylindrical portion, a cylindrical portion 48b having a smaller diameter than the cylindrical portion and having a hole formed on its side surface, and a conical portion 48c.
And a separator 48 that is concentric with the internal space is provided. The separator 48 is installed such that the lower side of the conical portion 48c has substantially the same height as the internal space side opening of the hydraulic oil supply passage 42c.

The hydraulic position adjusting device 4 having such a structure
Is the high pressure chamber 4 against the thermal expansion of the valve train member of the internal combustion engine.
The hydraulic oil in 3 is gradually released by the sliding surface between the main body 41 and the plunger 42 to shrink and absorb the amount of thermal expansion. When the amount of thermal expansion decreases, the plunger 42 is pushed up by the spring 45 in the high pressure chamber 43, and at the same time, the hydraulic oil is transferred to the plunger 42 via the ball valve 47.
The valve rush can be always maintained at zero by flowing into the high-pressure chamber 43 from the internal space and extending by the amount of decrease in the thermal expansion amount. In any of these states, the high pressure chamber 43 is filled with hydraulic oil of a predetermined pressure,
The vertical movement of the cam can be accurately transmitted to the intake valve 1.

The hydraulic oil supplied to the internal space of the plunger 42 is swirled in this internal space because the hydraulic oil supply passages 41a and 42c are offset with respect to the center of the internal space of the plunger 42. Form. As a result, a force toward the center acts on the granular air mixed in the hydraulic oil due to the difference in specific gravity. This air is pushed upward by the conical portion 48c of the separator 48,
Is discharged together with the hydraulic oil through the hydraulic oil discharge passage 42a,
It is used for lubrication between the rocker arm 3 and the upper portion of the plunger 42. Further, since the hydraulic oil supply passages 41a and 42c are directed obliquely upward, this air discharging action is further enhanced.

Further, foreign matter such as metal powder mixed in the hydraulic oil has a specific gravity larger than that of the hydraulic oil, so that a swirling flow of the hydraulic oil causes a radially outward force to act on the separator 4.
Settle outside on portion 48a of 8.

As a result, the cylindrical portion 48 of the separator 48 is
The hydraulic oil that has flowed through the holes formed in b into the internal space below the separator 48 is one in which air and foreign substances have been almost completely removed, and when the hydraulic position adjusting device 4 is extended. The hydraulic oil supplied to the high-pressure chamber 43 does not form an air layer in the high-pressure chamber 43, and the sealing failure of the ball valve and the sliding failure of the main body 41 and the plunger 42 due to foreign matter are prevented, and the cam is always operated. Vertical movement can be satisfactorily transmitted to the intake valve 1.

[0025]

As described above, according to the hydraulic position adjusting apparatus of the present invention, the working oil supplied to the high pressure chamber is the one in which air and foreign matter are completely removed, and the valve operating system of the internal combustion engine. The reliable operation of can be guaranteed.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a hydraulic position adjusting device according to the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

[Explanation of Codes] 4 ... Hydraulic Position Adjusting Device 41 ... Main Body 42 ... Plunger 41a, 42c ... Hydraulic Oil Supply Passage 43 ... High Pressure Chamber 48 ... Separator

Claims (1)

[Claims] 1. A main body having a side surface and a bottom surface, a hollow plunger slidably fitted in the main body, and a high pressure chamber defined by the lower portion and the main body, and the plunger having the high pressure. An elastic means for urging the chamber in the direction of expansion, an opening provided with a valve that allows only the flow of the hydraulic oil from the internal space of the plunger to the high pressure chamber, and both side surfaces of the main body and the plunger. A hydraulic oil supply passage that penetrates and is formed so that a swirl flow of hydraulic oil is generated in the internal space of the plunger, and the internal space of the plunger is divided into the opening side and the hydraulic oil supply passage side, and at least A portion above the hydraulic oil supply passage has a conical shape that is substantially concentric with the internal space of the plunger and has a convex shape upward, and a portion below the hydraulic oil supply passage has the opening side and the operating side. oil A hydraulic position adjusting device, comprising: a separator formed with a hole communicating with the supply passage side.