JPH0232804Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention [Field of industrial application] This invention is a valve train for an overhead valve type internal combustion engine, especially an internal combustion engine with a structure in which the cylinder is horizontally or slightly upwardly inclined. The present invention relates to a lubricating device.

[Conventional technology]

As described in Japanese Patent Application Laid-open No. 59-70838, if a vertical internal combustion engine is made into an overhead valve type and the intake valve is placed on the upper side and the exhaust valve is placed on the lower side,
In addition to simplifying the valve mechanism, there are various advantages to the intake system and exhaust system.

In addition, a breather passage leading from the crank chamber to the rocker arm chamber is provided to discharge oil droplets into the rocker arm chamber, and the oil that drips and accumulates in the rocker arm chamber is returned to the crank chamber, thereby forming a lubricating device for the valve mechanism. . This lubricating device has a simple structure because an oil discharge hole and an oil return hole are formed in the partition wall of the rocker arm chamber, and a breather gas containing oil droplets is used.

[Problem that the invention attempts to solve]

However, since the oil discharge hole is provided at the upper end of the partition wall and the oil return hole is provided at the lower end, a large amount of oil is sprayed directly onto the stem of the intake valve located on the upper side.
The oil flows down the stem and enters the combustion chamber, causing so-called oil drop. A similar problem occurs even when the intake valve and the exhaust valve are arranged side by side.

The object of the present invention is to reduce oil dripping from the intake valve.

B. Structure of the invention [Means for solving the problems] In order to achieve the above object, the present invention provides an overhead valve type internal combustion engine in which the cylinder 1 is horizontally or slightly inclined upward.
A stem is made to protrude from the partition wall 5 of the rocker arm chamber 4 to either the left or right side of the rocker arm chamber 4, and an oil discharge hole 6 is provided at the upper end of the partition wall 5 of the rocker arm chamber 4.
An oil return hole 7 is opened at the lower end, and a partition wall 8 for preventing oil flying agents is provided in the direction of the stem of the intake valve 2 in a direction that crosses a line connecting the oil discharge hole 6 and the stem of the intake valve 2. , the side of the intake valve 2 opposite to the stem is a lubricating device for an open valve mechanism.

[Effect]

When the internal combustion engine is operated, oil droplets are discharged from the oil discharge hole 6 into the rocker arm chamber 4.
The inside is moistened with oil. The oil that drips and accumulates at the bottom of the rocker arm chamber 4 returns to the crank chamber through the return hole 7.

Of the oil droplets coming out of the discharge hole 6, those that scatter in the direction of the stem of the intake valve 2 are blocked by the partition wall 8 for preventing oil scattering, and the amount of oil directly applied to the stem of the intake valve 2 is reduced.

〔Example〕

The figure shows a so-called vertical type overhead valve type internal combustion engine in which the crankshaft 9 is arranged vertically.
is placed with the top facing up. Therefore, the rocker arms 10 and 11 are vertically arranged in parallel. 12 is a push rod for the intake valve, 13 is a push rod for the exhaust valve, and 14 and 15 are bosses for screwing in the rocker arm pivot bolt.The oil discharge hole 6 is located at the center of the upper end of the partition wall 5 of the rocker arm chamber 4, and the oil return hole is located at the center of the lower end. Hole 7 is open.

The pivot bolt screwing boss 14 of the intake valve rocker arm 10 and the side wall 4 of the rocker arm chamber 4 are arranged so as to cross between the oil discharge hole 6 and the intake valve 2.
A partition wall 8 is provided to connect A. The partition wall 8
is gradually lowered toward the boss 14 to ensure a certain amount of oil for lubrication and cooling.

In the case of an overhead valve type engine in which intake valves and exhaust valves are arranged side by side, a partition wall for preventing oil scattering is provided only on the intake valve side.

A wind guide cover 17 is attached to cover the upper part of the cylinder 1 and a crankcase 16 integrated therewith, and a flywheel 18, a fan 19, and a recoil starter 20, which are integrated with the crankshaft 9, are located therein. The fuel tank 21 is attached to the side surface of the crankcase 16 on the opposite side from the cylinder 1.

C. Effects of the invention The present invention has the above-mentioned configuration of a lubricating device for a valve mechanism in an internal combustion engine having an overhead valve type structure in which the cylinder is horizontally or slightly tilted upward. The amount of discharged oil droplets directly applied to the stem of the intake valve 2 is reduced, which has the effect of reducing the amount of oil flowing through the stem of the intake valve 2 into the combustion chamber.

[Brief explanation of the drawing]

Fig. 1 is a side view of an overhead valve type vertical internal combustion engine embodying the present invention, Fig. 2 is an enlarged front view showing the inside of the rocker arm chamber, Fig. 3 is a vertical sectional view taken along the line of Fig. 2, FIG. 4 is a longitudinal sectional view taken along the line of FIG. 2. 1 is a cylinder, 2 is an intake valve, 3 is an exhaust valve, 4 is a rocker arm chamber, 5 is a partition wall, 6 is an oil discharge hole, 7 is an oil return hole, 8 is a partition wall, 9 is a crankshaft, 10,
11 is a rocker arm, 12 and 13 are push rods, and 14 and 15 are bosses for screwing in rocker arm pivot bolts.

Claims (1)

[Claims for Utility Model Registration] (1) In an overhead valve type internal combustion engine in which the cylinder is horizontally or slightly tilted upward, the stem of the intake valve is moved from the partition wall of the rocker arm chamber to either the left or right side of the rocker arm chamber. Make it protrude, make an oil discharge hole at the upper end of the partition wall of the rocker arm chamber, and an oil return hole at the lower end, and cross the line connecting the oil discharge hole and the intake valve stem in the direction of the intake valve stem. A lubricating system for the valve train of an internal combustion engine with a partition wall to prevent oil scattering and the side opposite to the intake valve stem open. (2) The lubricating device for a valve train for an internal combustion engine according to claim 1, wherein the partition wall for preventing oil scattering is provided from the side wall of the rocker arm chamber to the boss for screwing in the pivot bolt of the rocker arm for the intake valve. (3) The lubricating device for a valve train for an internal combustion engine according to claim 2, wherein the partition wall for preventing oil scattering is gradually lowered toward the boss for screwing in the pivot bolt of the intake valve rocker arm.