JPH0543209Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a valve mechanism for an internal combustion engine.

[Prior art] The valve mechanism of an internal combustion engine is, for example,
As disclosed in No. 198304, the end of the rocker arm rotated by the cam hits the exhaust valve stem,
When the exhaust valve is pushed down, the exhaust port is opened. In order to absorb shape errors in the cam surface, a valve gap is provided between the end of the rocker arm 5 and the exhaust valve stem 2, so that the exhaust valve is completely seated on the valve seat of the exhaust port. The state is obtained. However, such a valve gap also creates a gap (play) between the constituent members of the valve mechanism, which gives a shock to the valve mechanism as the exhaust valve opens and closes, and also causes damage to the exhaust valve. Because of the problem of abnormal opening and closing operations, the above-mentioned prior art is configured such that the end of the rocker arm is constantly pressed against the valve stem by a spring.

By the way, in an internal combustion engine equipped with an exhaust brake, when the exhaust valve is closed due to high engine speed, the internal pressure in the exhaust pipe increases, and this internal pressure pushes the exhaust valve open, resulting in the so-called exhaust valve jump phenomenon. . When the exhaust valve comes into contact with the valve seat again after the exhaust valve jumps, in the conventional technology described above, the rocker arm is rotated via the exhaust valve stem, and the other end of the rocker arm is violently pushed against the camshaft directly or through the push rod. This may cause a collision and cause problems such as pitting between the cam surface and the tappet.

Note that even if the valve stem is not pressed against the rocker arm by the spring as in the prior art described above, if a jump occurs in the exhaust valve due to an increase in the internal pressure of the exhaust pipe when the exhaust brake is activated, the seated seat after the jump occurs. Due to the impact of time, impact acts on the members of the valve mechanism, which may cause wear or breakage. This is caused by the exhaust valve jump between the exhaust valve and the rocker arm, between the adjustment bolt and the push rod, between the push rod and the tappet,
Due to mutual collision in the gap between the tappet and the cam.

[Problems to be solved by the invention] Therefore, the purpose of the invention is to apply pressurized lubricating oil to the wall surface of the rocker arm facing the exhaust valve stem when the exhaust brake is activated, thereby pushing up the rocker arm and closing the exhaust valve. An object of the present invention is to provide a valve train mechanism for an internal combustion engine in which the valve train mechanism is prevented from drifting or colliding with impact force after an exhaust valve jump by maintaining no gaps in the valve train mechanism except for .

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention is such that an oil jet is disposed toward the wall surface of the rocker arm facing the exhaust valve stem, and a pipe connecting the oil jet and the oil gear gallery of the engine is provided. The exhaust brake is equipped with a solenoid valve that opens when the exhaust brake is activated.

[Operation] When the exhaust brake activation switch 23 is closed,
The solenoid valve 19 opens, and the oil being pumped from the oil pump 25 to the oil gear gallery 20 is ejected from the oil jet 13 to the end of the rocker arm 5 via the solenoid valve 19 of the pipe 24, the check valve 15, and the pipe 14. Therefore, the other end of the rocker arm 5 is pressed against the push rod 8 via the adjustment bolt 7, and the push rod 8 presses the valve lifter 9 against the cam of the camshaft 10, thereby eliminating the gap in the valve mechanism and closing the exhaust valve. When the valve closes after the jump in step 2, collision between the structural members in the valve mechanism is avoided, and the durability life is extended.

[Example of the invention] The invention will be explained based on an example. As shown in FIG. 1, in the valve operating mechanism, one end of the rocker arm 5 rotatably supported by the rocker shaft 6 extends above the end of the stem of the exhaust valve 2, and the valve mechanism moves the exhaust valve against the valve spring 3. 2 is configured to open the exhaust port when pressed down.

A retainer 4 is supported on the stem of the exhaust valve 2 via a known connector, and a valve spring 3 is interposed between the retainer 4 and the wall of the cylinder head, so that the exhaust valve 2 is connected to the valve of the exhaust port. It is pressed against the seat to close the exhaust port.

On the other hand, an adjustment bolt 7 is supported at the other end of the locker arm 5, and this spherical end is connected to the push rod 8.
is collided with. The lower end of the push rod 8 abuts against a valve lifter 9, and the valve lifter 9 is pushed up by the cam of the camshaft 10. The configuration of such a valve mechanism is substantially the same as that of a conventional valve mechanism.

According to the present invention, an oil jet 13 is disposed toward the wall surface of the rocker arm 5 facing the exhaust valve 2, and oil pressurized by the oil pump 25 of the engine is spouted from the oil jet 13. . Lubricating oil is pumped to the oil gear gallery 20 from an oil pump 25 driven by the engine. A pipe 14 is connected from this oil gear gallery 20 via a pipe 24 having a solenoid valve 19 and a check valve 15.
An oil jet 13 is connected to this. When the exhaust brake is applied, the switch 23 is closed, electricity is supplied from the power battery 21, and the solenoid valve 19 is opened.

In addition, the check valve 15 has a housing 17 formed with a chamber 12 that communicates the pipes 24 with the pipes 14, and a valve body 18 fitted in the housing 17 and biased by a spring 16 that allows the pipes 24 and 14 to be spaced apart from each other. Usually blocked.

Next, the operation of the valve train mechanism for an internal combustion engine according to the present invention will be explained. The oil pressure of the oil pump 25 increases almost in proportion to the engine speed, and this upper limit pressure is suppressed by the action of a relief valve (not shown). Therefore, when the engine is rotating at a high speed that requires an exhaust brake, the oil pressure being sent from the oil pump 25 to the oil gear gallery 20 reaches the relief pressure.

When the switch 23 for operating the exhaust brake is closed, the solenoid valve 19 is opened, and the pressure oil in the oil gear gallery 20 enters the chamber 12 of the check valve 15 from the pipe 24, pushing down the valve body 18 and opening the inlet of the pipe 14. tube 14
from oil jet 13 to rocker arm 5.
It is squirted to the tip of. This ejection pressure causes the rocker arm 5 to rotate clockwise around the rocker shaft 6. Therefore, the adjusting bolt 7 is pushed down, and the valve lifter 9 is pressed against the cam surface of the camshaft 10 via the push rod 8, thereby removing the gap between these components.

When the exhaust pipe is closed due to activation of the exhaust brake, the internal pressure of the exhaust pipe increases, and the exhaust valve 2 may open against the valve spring 3. This exhaust valve 2
When the exhaust valve 2 is seated again after the jump, the exhaust valve stem will violently collide with the tip of the rocker arm 5, but in this invention, the components from the rocker arm 5 to the cam are closely spaced without any gaps. Therefore, the collision only occurs between the valve stem and the rocker arm 5, and no collision occurs in other parts.
Therefore, it is possible to prevent the durability of the valve mechanism from decreasing due to collisions between the component members.

[Effects of the invention] As described above, the present invention has an oil jet disposed facing the wall surface of the rocker arm facing the exhaust valve in a conventional valve mechanism, and pressurization from the oil pump is applied to this oil jet when the exhaust brake is activated. Since the system is designed to eject oil, the gaps between the parts that make up the valve mechanism, from the camshaft to the rocker arm, are removed, and the rocker arm is able to release the exhaust gas as the exhaust valve returns after jumping. Even if the valve collides with the rocker arm, collisions with other components of the valve mechanism are avoided, preventing uneven movement and wear and tear of each component due to this collision, and maintaining the durability of the valve mechanism. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a valve mechanism for an internal combustion engine according to the present invention, and FIG. 2 is a diagram showing the characteristics of an oil pump used in the valve mechanism for the internal combustion engine. 13...Oil jet, 15...Check valve, 1
9... Solenoid valve, 20... Oil gear rally, 23...
...Switch for exhaust brake activation, 25...Oil pump.

Claims (1)

[Scope of utility model registration request] A valve train for an internal combustion engine, characterized in that an oil jet is disposed toward a wall surface facing an exhaust valve stem of a rocker arm, and a solenoid valve that opens when the exhaust brake is activated is provided in a pipe connecting the oil jet and an oil gear gallery of the engine. mechanism.