JPS5891316A - Overhead valve type control velve mechanism - Google Patents

Abstract

PURPOSE:To hole constantly and properly a tappet clearance by providing a hydraulic type locker arm support shaft device which automatcilly adjusts the clearance in the title overhead vavle type control valve mechanism in the internal combustion engine. CONSTITUTION:Cylinder parts 9 and 10 are formed in a head cover 8. A hydraulic type locker arm support shaft device which pivotally supports locker arms 29 and 30 of the overhead valve type control valve mechanism, is provided in cylinder parts 9 and 10 of the head cover 8 in a freely entering and leaving manner. Since the hydraulic type locker arm device can suitably enter or leave to follow the mvements of the locker arms, 29 and 30 the tappet clearance can be held appropriately at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overhead valve type valve mechanism that automatically adjusts the clearance of the valve mechanism and is easy to assemble.

In a conventional overhead valve type valve train, the rocker arm is swingably supported by the cylinder head, and when there is a large clearance between the intake/exhaust valve and the rocker arm in the closed state, the rocker arm is pivoted to the cylinder head. The clearance was adjusted to an appropriate value by appropriately turning an adjustment screw attached to the tip.

This adjustment work had to be done for each intake and exhaust valve for each cylinder, which required time and effort to assemble and maintain.

In addition, in conventional overhead valve type valve train mechanisms, the rocker arm is swingably supported by the cylinder head, so the rocker arm must be pivoted to the cylinder head after the intake and exhaust valves are mounted on the cylinder head. Not,
Assembling and disassembling a valve trainThe purpose of the improvement of a valve train is to provide a valve train that is easy to assemble, disassemble, and maintain.An embodiment of the present invention is shown in the drawings below. I will explain about it.

Reference numeral 1 denotes a cylinder head of a four-stroke gasoline engine, and the cylinder head is formed with a small-diameter intake boat 2 and a large-diameter exhaust boat 3, so that the intake and exhaust boats 2.3 can be opened and closed at will. An intake valve 4 and an exhaust valve 5 are fitted so as to be openable and closable.

Further, the intake/exhaust valve 4.5 includes the intake/exhaust boat 2.3.
Compression coil springs 6 are attached to the respective sides in such a direction that they can be closed at all times.

Further, a cam 7 is pivotally supported between the intake and exhaust valves 4.5, and the cam 7 is connected to a crankshaft (not shown) via a chain and a sprocket, and the cam 7 is connected in synchronization with the rotation of the crankshaft. 7 is designed to be rotationally driven.

Furthermore, a cylinder head cover 8 is provided to cover the intake and exhaust valves 4.5, coil springs 6 and cams 7.
is detachably attached to the cylinder head 1.

Further, cylinder parts 9.10 are formed in the cylinder head cover 8, respectively, and are located between the intake and exhaust valves 4.5 and the cam 7, and are directed downward. Hydraulic rocker arm support shaft device 11.1
2 are fitted in such a way that they can appear and retract freely.

Further, oil supply bows 13.14 are opened at the center of the peripheral wall of the cylinder part 9.10, and oil supply passages 15 and i6 are provided in the oil supply bows 13.1.4.
are connected, and the bases of the oil supply paths I5.16 are collected together and connected to the oil supply pipe 17, and oil pumped from an oil pump (not shown) to the oil supply pipe 17 is transferred to the oil supply path 15.16. The oil is supplied to the cylinder part 9.10 from the oil supply boat 13.14 via the oil supply port 16.

Therefore, the hydraulic rocker arm support shaft device 11.1
2 have the same structure, the description of the hydraulic rocker arm support shaft device 11 will be omitted, and only the detailed structure of the hydraulic rocker arm support shaft device 12 will be described.

The hydraulic rocker arm support shaft device 12 has a hollow adjuster body 18 with a hemispherical tip and an open base.
A leak down plunger, a plunger 19 and a plunger are slidably fitted into the adjuster body 18, and the plunger is fitted onto the base end of the adjuster body 18 so as not to protrude beyond a certain length. the retainer cap 21, the plunger spring that urges the leak down plunger 19 upward via the check ball case n, and the leak down plunger 19.
The check ball case n and the check ball case n are pressed together so that the check ball case is brought into pressure contact with the tip valve seat 19a of the valve seat 19a.
24 and a check ball spring 5 interposed therein.

In addition, an oil return passage n1 is formed at the top of the cylinder part 9, lo, and is directed diagonally downward. The oil that has reached the portions 9 and 10 is injected from the oil return passages 27 and 28 toward the intake and exhaust valves 4.5, the cam 7, and the rocker 4.

Further, a slight gap is formed between the outer circumferential surface of the leak down plunger 19 and the flancher and the inner circumferential surface of the adjuster body 8.

In addition, the hydraulic rocker arm support shaft device ti, %1
Rocker arms 29 and 30 are pivotally supported at the tips of rocker arms 4 and 2, and protrusions 31 and 32 protruding from both sides of the center of rocker arms 4 and 1 are attached to protrusions of a holding plate 33, and the same When one end of the rocker arm 29, 30 is engaged with the upper end of the intake valve 4 and the exhaust valve 5, respectively, the other end of the rocker arm 4, (9) is engaged with the number i cam 7,
The above-mentioned mounting is such that it can be mounted to the cylinder head cover 8 using a presser plate (Pol) 35.

Since the illustrated embodiment is configured as described above, even when the cylinder head cover 8 is removed from the cylinder head 1, the upper end of the plunger is pressed by the spring force of the plunger spring B into the cylinder part 9, lO.
The adjuster body 18 is pressed against the top surface of the adjuster body 18.
is forced downward and the rocker arm is pressed down to the protrusion 3 of (9).
1.32 is attached to a protrusion of the holding plate 33, and the hydraulic rocker arm support shaft device 1112 and the rocker arm 29.30 are supported by the cylinder head cover 8.

When the cylinder head cover 8 is attached to the cylinder head 1 in this state, the rocker arm 29.30
When one end is engaged with the upper ends of the intake valve 4 and the exhaust valve 5, the other end of the rocker arm 30 is engaged with the cam 7, and the hydraulic rocker is activated by the spring force of the compression coil spring 6. The plunger spring B in the arm support shaft device 11.12 is compressed and the adjuster body 18 is moved slightly upwards.

When the engine is in operation, an oil pump (not shown) is operated to connect the oil supply pipe I7 to the oil supply passage 15.1.
Oil is supplied to the oil supply boats 13 and 14 through holes 6 and 14, and the oil is supplied from hole +8a of the adjuster body 18 to the reservoir chamber through the plunger hole 20a. The pressurized oil in the reservoir chamber is transferred to the high pressure chamber 1 at the tip of the adjuster body 18 through the check pole prisoner.
8b, the high pressure chamber 18b is filled with oil, and the remaining oil is sent to the top of the cylinder part 9.10 via the passage 20b, and the remaining oil is sent to the top of the cylinder part 9.10 through the oil return passage γ, More sprayed.

When a clearance is created between the rocker arm 29.30, the intake/exhaust valve 4.5, and the cam 7, the spring force of the plunger spring O is applied to the adjuster body 18.
When the valve is lowered, the check ball U moves away from the tip valve seat 19a of the leak down plunger 19 due to the pressure drop in the high pressure chamber 18b, and the oil in the reservoir chamber % is supplied into the high pressure chamber 18b. Ru.

Further, when the cam ridge of the cam 7 approaches the other end of the rocker arm 29.30 and the other end of the rocker arm 29.30 is pushed up by the cam ridge of the cam 7, the lower end of the adjuster body 18 also moves upward. Therefore, the oil in the high pressure chamber 18b is pressurized to a high pressure, and the IJ-down plunger 19 and the plunger pressure and adjuster body 18 are pushed up.
The reservoir chamber is refluxed into the reservoir chamber through the hole 20a from the gap.

By repeating these operations, the adjuster body 8 moves up and down, the fulcrum of the rocker arm 4, (g) is changed, and the tappet clearance is maintained at an appropriate value.

In this way, the tappet clearance is automatically adjusted, reducing the noise of the valve mechanism, and also eliminating the need for some manual adjustment work, making it possible to improve assembly and maintainability.

Furthermore, it is easy to apply to other models and has wide versatility.

Furthermore, hydraulic p-tsuka arm support shaft device 11.12
To guide the oil used in the oil return passage n1 to the slipper surface of the cam 7, the rocker arm 4, (9), and the sliding contact surface of the hydraulic rocker arm support shaft device 11, 12, and the rocker arm 4, joint. As a result, friction and wear of the valve mechanism can be reduced.

Also, the protrusions 31 and 32 on both sides of the rocker arm 29 and 30 are attached to the protrusions of the holding plate 33 and the cylinder head cover 8.
Hydraulic rocker arm support shaft device 11.1
Since the lower end of 2 is in contact with the rocker arm 4 (9), even if the cylinder head cover 8 is removed from the cylinder head 1, the hydraulic rocker arm support shaft device 11, 12 and the rocker arm 4, is attached to the cylinder head cover 8, and there is no need to pay attention to prevent the hydraulic rocker arm support shaft device 11, 12, which is fitted downward and fitted R, from coming off, improving the efficiency of assembling and disassembling the valve mechanism. becomes possible.

The present invention provides an internal combustion engine equipped with an overhead valve type valve mechanism and a head cover that covers the synchronized valve mechanism, as described above, in which a part of the cylinder is formed in the head cover, and a rocker arm of the valve mechanism is pivoted. A hydraulic rocker arm support shaft device that automatically adjusts the clearance when supporting the engine is fitted in a part of the cylinder of the head cover so as to be freely protrusive and retractable. The hydraulic rocker arm support shaft device can move in and out as needed to follow the movement, and as a result, tappet clearance can always be kept at an appropriate level. Therefore, in the present invention,
The noise of the valve mechanism can be reduced.

Further, in the present invention 1, the rocker arm is engaged (1).
- Since the mounting plate is attached to the head cover, even if the hydraulic rocker arm support shaft device is attached to the cylinder head cover so as to protrude downward, even when the head cover is attached or detached, the hydraulic rocker arm The attachment plate can prevent the rocker arm support shaft device from falling through the rocker arm, and the ease of assembly, disassembly, and maintenance of the valve mechanism can be improved.

Although the present invention has been described above in detail with reference to the embodiments illustrated in the drawings, the present invention is not limited to such embodiments, and can be freely modified as necessary without departing from the spirit of the present invention. This is because the design has been modified.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view of the essential parts of an embodiment of the overhead valve type valve operating mechanism according to the present invention, FIG. 2 is an enlarged vertical sectional side view of the essential parts, and FIG. A partially longitudinal side view illustrating the supported state, FIG. 4 is the TV- shown in FIG.
FIG. 5 is a perspective view of the mounting plate. 1... Cylinder head, 2... Intake boat, 3.
...Exhaust boat, 4...Intake valve, 5...Exhaust valve, 6
...Compression coil spring, 7...Cam, 8...
Cylinder head cover, 9, IO... Cylinder part, 11.12... Hydraulic rocker arm support shaft device,
13.14...Oil supply bow), 15.16...
Oil supply path, 17...Oil supply pipe, 18...Adjuster body, 19...Leak down plunger, addition...Plunger, 21...Retainer cap, 22...Check ball case, B... Plunger spring, 24... Check ball, 6...
・Check ball spring, ga...Lisano cooling chamber, 27, ah...oil return passage, 4, addition...rocker arm, 31.32...protrusion, 33...installation is by holding plate, support plate, etc. ... protrusion, 35... bolt. Agent Patent Attorney Ehara Nozomi 1 name leather 2 illustrations

Claims (1)

[Claims] In an internal combustion engine equipped with an overhead valve type valve mechanism and a head cover that covers the synchronized valve mechanism, if a part of the cylinder is formed in the head cover and a rocker arm of the valve mechanism is pivotally supported, clearance can be improved. An overhead valve type actuator characterized in that an automatically adjusting hydraulic rocker arm support shaft device is fitted in the cylinder of the head cover so as to be able to freely move in and out, and a holding plate is attached to the head cover to lock the rocker arm. Valve mechanism.