JPH0350304A - Locker arm - Google Patents

Abstract

PURPOSE:To make a locker arm smaller, improve strength and rigidity, increase designing freedom and so on by separating an oil storage chamber from a plunger, and constructing it between a bearing part and a bearing part in a locker arm. CONSTITUTION:In a locker arm 1, its center is supported by a locker shaft 9 so that it may oscillate freely, and a valve is pushed down by the force from a cam at one end through a plunger 2 on the other end. The locker arm 1 consists of a bearing part 14 fitted to the locker shaft 9 so that it may oscillate freely and an arm part connecting the bearing part 14 and an oscillating end 15. In the arm 13, an oil storage chamber 7 of prescribed volume is formed. In the locker arm 1, there are respectively provided an oil passage 16 leading oil to an oil storage chamber 7 through a peripheral groove 23 from a main gallery 21, and an oil passage 17 leading oil to a high pressure chamber 6 from the oil storage chamber 7. In a plug 33 on the top of the oil storage chamber 7, an air vent hole 34 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rocker arm for an internal combustion engine incorporating a hydraulic valve gap adjustment device.

(Prior Art) As a conventional device of this type, there is one shown in FIG. 3, for example (see Japanese Patent Laid-Open No. 162310/1983).

To explain this, a plunger 52 that is slidably fitted into a rocker arm 51 and a return spring 54 that presses the plunger 52 against a valve 53 are provided, and a check ball 55 is installed inside the plunger 52.
A high pressure chamber 56 is defined which is closed via a casing 58, and an oil reservoir chamber 57 for storing a predetermined amount of oil is defined inside the planter 52 via a casing 58.

Hydraulic pressure is used to constantly maintain the gap between the plunger 2 and the valve 3 at zero, absorb thermal deformation, and reduce noise.

(Problem to be Solved by the Invention) However, in such a conventional device, since the oil reservoir chamber 57 is provided inside the plunger 52 via the casing 58, the axial strength of the plunger 52 is large. As a result, the degree of freedom in designing the valve train is reduced, and the oil sump chamber 5
There were problems in that it was difficult to secure sufficient capacity for the engine, and the engine became larger.

The present invention aims to solve these conventional problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes: a bearing portion rotatably fitted to the rocker shaft; a silling portion into which a plunger abutting the valve is slidably fitted; a high pressure chamber defined between the silling part and the plunger, an oil sump chamber formed between the silling part and the bearing part and having a predetermined volume, and an air vent hole opening at the top of the oil sump chamber; The oil reservoir chamber is provided with an oil passage that leads oil from the main gear rally in the rocker shaft, and an oil passage that leads oil from the oil reservoir chamber to the high pressure chamber via a check valve.

(Function) By separating the oil reservoir chamber from the plunger and providing it inside the rocker arm, the swinging tip of the rocker arm can be prevented from increasing in size in the axial direction of the plunger, and the strength and rigidity of the rocker arm can be increased. In addition to increasing the degree of freedom in designing the valve train, it also reduces inertia mono to accommodate higher engine speeds.

In addition, by separating the oil sump chamber from the plunger and installing it inside the rocker arm, it is possible to secure a sufficient volume of the oil sump chamber in a limited space. It is separated and discharged from the air bleed hole, and the plunger is held by air-free oil to ensure good operability.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the rocker arm 1 is swingably supported at its center by a rocker shaft 9, and the force of a cam received at one end (not shown) pushes down a valve (not shown) via a plunger 2 at the other end. It is.

The swinging tip 15 of the rocker arm 1 is provided with a silling portion 11 into which the plunger 2 is slidably fitted, and four portions 12 coaxially formed with the silling portion 11, each having a circular cross section. A high pressure chamber 6 is defined between the plunger 2 and the plunger 2 via the four parts 12. Schilling part 11
Since it is formed integrally with the rocker arm 1, the number of parts can be reduced, making it more compact and lightweight.

The rocker arm 1 has a bearing part 14 that is swingably fitted to the rocker shaft 9, and an arm part 13 that connects the bearing part 14 and the swinging tip part 15, and the arm part 13 has an oil reservoir having a predetermined volume. 7 is formed.

That is, the oil reservoir chamber 7 is located inside the rocker arm 1 and the bearing portion 1 is located inside the rocker arm 1.
4 and the sill portion 11.

On the other hand, inside the rocker shaft 9 is a main gear rally 21 through which pressurized oil sent from the engine's oil pump circulates.
will be provided.

A circumferential groove 23 is formed in an annular shape between the rocker shaft 9 and the rocker arm 1, and an oil passage 22 is formed in the rocker arm 1 to guide oil from the main gear rally 21 to the oil reservoir chamber 7 via the circumferential groove 23.

An oil passage 17 is formed in the rocker arm 1 to guide oil from the oil reservoir chamber 7 to the high pressure chamber 6. A plug body 31 is press-fitted into one end of an oil passage (through hole) 17 that is bored through the silling portion 11 .

A circumferential groove 24 that opens the oil passage 17 is formed between the plunger 2 and the silling part 11, and the plunger 2
Through holes 25 and 26 are formed to connect the circumferential groove 24 and the high pressure chamber 6, respectively.

A return spring 4 is interposed between the four parts 12 and the plunger 2 to bias the plunger 2 in the projecting direction.

A seat portion 30 on which the check ball 8 is seated is formed at the opening of the through hole 26 to the high pressure chamber 6 . Seat part 3
0 is formed on the plunger 2, sufficient machining accuracy is ensured and the sealing performance of the high pressure chamber 6 is improved.

The check ball 8 is pressed against this seat portion 30 by the spring 28. A retainer 29 is interposed between the spring 28 and the return spring 4.

An O-ring 32 is interposed between the silling portion 11 and the plunger 2 to keep this portion oil-tight.

A plug 33 is press-fitted into the upper part of the oil reservoir chamber 7, and an air vent hole 34 is formed in the plug 33.

The air vent hole 34 opens at the top of the oil reservoir 7 , the oil passage 16 opens at the side of the oil reservoir 7 , and the oil passage 17 opens at the bottom of the oil reservoir 7 .

The ceiling portion 7a of the oil reservoir chamber 7 defined by the plug 33 is formed higher than the ceiling portion 6a of the high pressure chamber 6 by a predetermined distance.

Next, the effect will be explained.

If no force is applied to the plunger 2 when the valve is closed, the biasing force of the return spring 4 will cause the plunger 2 to
As the valve is pushed out, the pressurized oil opens the check ball 8 and flows into the high pressure chamber 6, reducing the valve gap to zero.

When the plunger 2 receives an upward force from the cam during the next valve opening operation, the oil in the high pressure chamber 6 tries to flow backwards, but since the check ball 8 is seated on the seat part 30, the oil is trapped. It will be done. As a result, the rocker arm 1 and the plunger 2 work together to push down the valve.

Air is mixed in the oil that flows from the main gear rally 21 of the rocker arm 1 through the oil passage 16 into the oil reservoir chamber 7, but by ensuring a predetermined volume in the oil reservoir chamber 7,
While oil is stored in the oil sump chamber 7, it collects at the upper part of the oil sump and is discharged from the air vent hole 34.

The oil reservoir chamber 7 is provided at a higher position than the high pressure chamber, and since the oil passage 17 that leads oil from the oil reservoir chamber 7 to the high pressure chamber 6 opens at the bottom of the oil reservoir chamber 7, air is removed. Oil is led to high pressure chamber 6.

By separating the oil reservoir chamber 7 from the plunger 2 and providing it inside the rocker arm 1, a sufficient volume of the oil reservoir chamber 7 can be secured in a limited space, so that the residence time of oil in the oil reservoir chamber 7 can be reduced. By increasing the length of the plunger 2, air bubbles in the oil are sufficiently separated, and the plunger 2 is held by air-free oil to obtain good operability.

In addition, by providing the oil reservoir chamber 7 inside the rocker arm 1 separately from the fin gear 2, the swinging tip 15 of the rocker arm 1 becomes larger in the axial and radial directions of the plunger 2. By avoiding this, a decrease in the strength and rigidity of the rocker arm 1 can be suppressed, the degree of freedom in designing the valve train can be increased, and the moment of inertia can be reduced to cope with higher speeds of the engine.

Next, in another embodiment shown in FIG. 2, a second oil reservoir chamber 43 is formed inside the plunger 42.

The plunger 42 is formed by fixing two upper and lower members 44.45, and a second oil reservoir chamber 43 is defined between the upper and lower members 44.45.

Inside the rocker arm 1, an oil reservoir chamber 7 is formed between the cylinder section 11 that houses the plunger 42 and the bearing section 14.
The oil is guided to the second oil reservoir chamber 43 through. and,
Oil is guided from the second oil reservoir chamber 7 to the high pressure chamber 6 through the through hole 48 and by opening the check ball 8.

In this case, when the plunger 2 protrudes to fill the valve gap when the valve is closed, the oil stored in the second oil reservoir chamber 43M passes through the relatively short passage hole 48 and quickly enters the high pressure chamber 6. Since it is inhaled, the operational response of the plunger 42 can be increased.

(Effects of the Invention) As described above, according to the present invention, in a rocker arm equipped with a hydraulic gap adjustment device, the oil reservoir chamber is separated from the plunger and is formed inside the rocker arm between the cylinder part and the bearing part. This avoids the swinging tip of the rocker arm from increasing in size in the axial direction of the plunger, increasing the strength and rigidity of the rocker arm, increasing the degree of freedom in designing the valve train, and reducing the moment of inertia to increase the speed of the engine. In addition, it is possible to secure a sufficient volume of the oil reservoir chamber in a limited space and prevent deterioration of the plunger's operability due to air bubbles in the oil.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment, and FIG. 3 is a sectional view showing a conventional example. 1...Rocker arm, 2...Plunger, 4...
Return spring, 6... High pressure chamber, 7... Oil reservoir chamber, 8... Check ball, 9... Locker shaft 7),
11... Schilling part, 14... Bearing part, 21...
Main gear rally, 34...air vent hole.

Claims (1)

[Claims] A bearing part that rotatably fits into the rocker shaft, a cylinder part into which a plunger that contacts the valve is slidably fitted, a high pressure chamber defined between the cylinder part and the plunger, and a cylinder part and the bearing part. an oil sump chamber having a predetermined volume formed between the oil sump chamber and the oil sump chamber; an air vent hole opening at the top of the oil sump chamber; A rocker arm characterized in that each rocker arm is provided with an oil passage that guides oil from the chamber to the high pressure chamber via a check valve.