JPS6242083Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an air vent hole for a latch adjuster of an overhead camshaft (OHC) type internal combustion engine (hereinafter referred to as the engine).

In a conventional OHC type engine, as shown in FIG. 3, oil is pumped from an oil pump (not shown) to an oil pan (not shown) and is forced into the cylinder head 1 of the engine through an oil filter (not shown) and a main gear rally. The oil pressure-fed to the cylinder head 1 is transferred from the oil passage 12 to the latch adjuster mounting hole (hereinafter simply referred to as the mounting hole).
14 and is supplied to a lash adjuster (not shown). By the way, the gap between the lash adjuster and the mounting hole 14 is set to be very small, so when inserting the lash adjuster into the mounting hole 14, the air in the mounting hole 14 is compressed, making insertion difficult. . To solve this problem, an air vent hole 13 extending upward from the deepest part of the mounting hole 14 is provided in the cylinder head 1 to exhaust air.

However, if the engine is left for a long time after it has been operated and stopped, the oil filled in the lash adjuster (not shown) and the mounting hole 14 will gradually leak out from the air vent hole 13. The reason for this is that the opening 12a of the oil feed passage 12 to the attachment hole 14 is located at a higher position than the outlet 13a of the air vent hole 13 to the outside air. If oil leaks from the outlet 13a in this manner, air will enter the lash adjuster, impairing its function.

Furthermore, depending on the processing method, machining burrs may be generated in the opening 13b of the air vent hole 13 to the deepest part of the mounting hole 14, and this machining burr may impair the function of the lash adjuster. There are things that happen.

The purpose of this invention is to provide an air vent hole in an OHC engine that will not leak oil from the outlet of the air vent hole even if left for a long time after the engine has stopped operating, and will not cause burrs to form at the opening to the latch adjuster mounting hole. do.

This invention will be explained below based on drawings showing embodiments. Note that the same components as in FIG. 3 are given the same numbers and detailed explanation thereof will be omitted. Figure 1 A,
2 indicates the intake valve or exhaust valve of the OHC engine. 3 is a valve guide, 4 is a valve spring, 5 is a rocker arm, and 6 is a cam. A lash adjuster 7 is inserted into a lash adjuster mounting hole 14 provided in the cylinder head 1. The latch adjuster 7 includes a cylindrical plunger 7a, a body 7b interposed between the plunger 7a and the mounting hole 14, and a check ball 7.
c, a spring 7d inserted between the bottom of the plunger 7a and the bottom of the body 7b, and the retainer 7
e and a ball retainer 7f. A small hole 8 is provided in the body 7b, and a small hole 9 is provided in the plunger 7a above the small hole 8. The small hole 8 communicates the gap 11 between the cylinder head 1 and the body 7b with the gap 10 between the plunger 7a and the body 7b, and the small hole 9 communicates the gap 10 with the inside of the plunger 7a. The opening 12a of the oil feed passage 12 provided in the cylinder head 1 has a gap 1
1, that is, facing the mounting hole 14. 23 is an air vent hole provided in the cylinder head 1,
Its upper end communicates with the outside air through an outlet 23a, and its lower end communicates with the outside air through a partially arcuate slit 15 through a mounting hole 14.
is connected to. Exit 2 of air vent hole 23
3a is located above the opening 12a of the oil feed passage 12.

As in the conventional latch adjuster, the oil that is pumped from the oil passage 12 to the mounting hole 14 passes through the gap 11, the small hole 8, the gap 10, and the small hole 9, enters the plunger 7a, and enters the bottom of the body 7b. It also accumulates. As a result, the latch adjuster is held stationary, the upper end of the plunger 7a serves as a fulcrum for one end of the rocker arm 5, and as the cam 6 rotates, the rocker arm swings and pushes down the valve 2 with its other end. The valve 2 returns under the action of the valve spring 4.

If the engine is stopped and left for a long time, the oil in the gap 11 will enter the air vent hole 23 through the slit 15, but the outlet 23a is set at approximately the same height or higher than the opening 12a of the oil feed passage 12. Therefore, oil does not leak from the outlet 23a. Therefore, the latch adjuster is held in an immovable state and performs a sufficient function as a fulcrum for the rocker arm 6, increasing its durability. This in turn contributes to improvements in engine performance and fuel efficiency. Further, since the lower end of the air vent hole 23 communicates with the lower end of the mounting hole 14 through the partially arcuate slit 15, no burrs are generated at the lower end of the air vent hole 23. Therefore, the function of the lock adjuster is not impaired.

Figures 2A and 2B show a second embodiment of this invention.
The difference from the first embodiment is that the air vent hole 33 is not provided with the slit 15 at the lower end of the air vent hole 33 as in the first embodiment, but is gently inclined toward the mounting hole 14, and an opening to the mounting hole 14 is provided at the lower end. 33
b. Therefore, the opening 33b
No burrs occur. The other configurations are the same as in the first embodiment, and the operations and effects are also the same.

[Brief explanation of the drawing]

FIG. 1A shows a longitudinal sectional front view of the first embodiment of this invention, and FIG. 1B shows a schematic plan view of FIG. 1A. FIG. 2A shows a longitudinal sectional front view of the main part of the second embodiment of this invention, and FIG. 2B shows a schematic plan view of FIG. 2A. Figure 3A shows a schematic longitudinal sectional front view of the main parts of a conventional lash adjuster, and Figure 3B shows a
A schematic plan view of Figure A is shown. 1...Cylinder head, 2...Valve, 5...
Rocker arm, 6...Cam, 7...Lush adjuster, 12...Oil feed passage, 12a...Opening, 1
4...Lash adjuster mounting hole, 23, 33
...Air vent hole, 23a, 33a...exit.

Claims (1)

[Claims for Utility Model Registration] (1) A cam 6 and a rocker arm 5 driven by the cam 6 are arranged above the cylinder head 1, and one end of the rocker arm 5 is attached to the cylinder head 1.
Lash adjuster mounting hole 14 provided in
It is supported by the upper end of the latch adjuster 7 inserted therein, and the other end of the rocker arm 5 operates an intake valve or an exhaust valve.
The lash adjuster mounting hole 14 is located inside the lash adjuster 7 and in the gap between the lash adjuster 7 and the wall of the lash adjuster mounting hole 14.
Oil is supplied from an oil feed passage 12 having an opening facing the cylinder head 1, and the cylinder head 1 has air vent holes 23, 33 that communicate with the lower end of the lash adjuster mounting hole 14 at the lower end and communicate with the outside air at the upper end. In the internal combustion engine provided, the air vent holes 23, 33
The vertical positions of the outlets 23a and 33a to the outside air are set at approximately the same height as or higher than the position of the opening 12a of the oil feed passage 12 to the lash adjuster mounting hole 14. Features an air vent hole for the lash adjuster. (2) The air vent hole for a lash adjuster according to claim (1), wherein the air vent hole 23 communicates with the mounting hole 14 through a slit 15 at its lower end. . (3) The air vent hole 33 is connected to the mounting hole 1.
The air vent hole for a lash adjuster according to claim (1) of the utility model registration, characterized in that the air vent hole is gently inclined with respect to 4 and communicates obliquely with the mounting hole 14 at its lower end.