JPS6032909A - Device in tappet valve system of internal-combustion engine - Google Patents

Abstract

PURPOSE:To disuse a push rod and achieve higher rigidity and light-weight and compact design of a tappet valve system by driving two intake valves which are disposed per one cylinder, by means of a cam via a bridge. CONSTITUTION:An intake cam 10 and an exhaust cam are formed on a cam shaft 3 which is attached to a cylinder head 5. There are provided two intake valves 9a and 9B per one cylinder and both the valves 9A and 9B are opened and closed via bridge 11 by the intake cam 10. The intake valves 9A and 9B are lower than an exhaust valve by the height l1 of the bridge 11. The exhaust valve is opened and closed via a tappet by the exhaust cam. Consequently, there is no need of using a push rod having low rigidity in the tappet valve system of the intake valve requiring the need of driving the bridge 11 and higher rigidity and light-weight and compact design of the tappet valve system may be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve train for a three-valve internal combustion engine.

In a conventional valve train system for an internal combustion engine, a tappet-shaped cap 2 is placed over each valve head of an exhaust valve 1 and an intake valve (not shown), as shown in the longitudinal sectional view of the main part in FIG. An overhead cam type is used in which the exhaust valve 1 and the intake valve are driven by an exhaust cam 4 or an intake cam provided on a camshaft B on the cylinder head 5 via the cap 2.

Note that 6 in FIG. 1 is an exhaust boat, and 7 is a fuel injection valve.

However, in the valve train system of an overhead cam type internal combustion engine that drives the exhaust valve 1 and intake valve through camp 2 as described above, it is difficult to achieve high output because there is no increase in the amount of intake air at high speeds. .

On the other hand, a three-valve internal combustion engine with two intake valves and one exhaust valve in one valve can significantly increase intake air at high speeds, especially when combined with the intake inertia effect, resulting in high output. is obtained, but Utility Model Application No. 55-132342, Utility Model Application No. 56-1203
04, intake valve 2 as in Utility Model Application No. 56-120328 etc.
In order to drive the two intake valves at the same time, it is necessary to adopt a system in which a bridge that can open and close the two intake valves at the same time is installed on the cylinder block side and is driven via a camshaft push rod and an intake valve arm. However, due to the increased mass in the valve train, the valve train has problems in that its dynamic characteristics are not good, it lacks durability, and it is not possible to increase the speed of the engine.

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned conventional problems, and provides a low-cost and durable valve train system that can increase the speed and output of an internal combustion engine, make the valve arm chamber more compact, and provide a low-cost and durable valve train system. This was done for the purpose of providing equipment.

That is, the valve train system of the present invention is a three-valve internal combustion engine having one cylinder, two intake valves and one exhaust valve, in which a camshaft having an intake cam and an exhaust cam is provided in the cylinder head, and further The two intake valves can be opened and closed at the same time, and a bridge for operating the intake valve is provided at the upper center thereof and has a flat surface that can come into contact with the intake cam, and the exhaust valve has a bridge above the valve head of the exhaust valve that is connected to the exhaust cam. It is characterized by the provision of a cap that can be touched.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a plan sectional view of the main parts showing the valve arrangement of the valve train in the embodiment of the present invention, and FIG. 3 is the same as that of FIG. Fig. 4 is a plan view of the inside of the valve arm chamber showing the valve train system, and Fig. 4 is a vertical cross-sectional view of the main parts showing the driving parts of the two intake valves shown in Fig. 2, and the same parts as the conventional example shown in Fig. 1 are the same. Indicated by part number.

First, in the exhaust port B provided for one cylinder of the cylinder head 5 shown in FIG. 2, there is a port for one exhaust valve 1.
A is provided, and the intake boat 8 is provided with two intake valves 9A.
, 9B are provided, respectively, and an insertion hole 7A for the fuel injection valve 7 is provided in the center thereof.

Next, as shown in FIG. 3, a camshaft 6 is provided at the top of the cylinder head 5 of this three-valve internal combustion engine, and an exhaust cam 4 and an intake cam 10 are provided on this camshaft A. 1, a tappet-shaped camp 2 is provided above the valve head of the exhaust valve 1, and the camp 2 is brought into direct contact with the exhaust cam 4, so that the exhaust valve 1 is It is designed to be driven.

Further, on the upper part of the two intake valves 9A% and 9B, there is a bridge 11 for operating the intake valves that can open and close the intake valves 9A and 9B at the same time, as shown in FIG.
It is provided so as to be slidable up and down in the direction of arrow A-B via the bridge guide shaft 12.

Furthermore, a flat portion 11A that can come into contact with the intake cam 10 is provided at the upper center of the bridge 11.
Two intake valves 9A1'9B are connected via the bridge 11.
are activated at the same time.

Note that reference numeral 13 in the figure indicates a head bolt that fixes the cylinder head 5 to the block side.

In the valve train system of the present invention having the above configuration, the camshaft 6
almost at the center of the two intake valves 9A, 9B, and the exhaust valve 1.
Bridge 1 is placed on the top and operates the two intake valves 9 & 9B.
1 can be raised and lowered by the intake cam 10 of this camshaft B, and the intake valves 9A and 9B can be opened and closed at the same time.

Therefore, the height of the valve heads of the intake valves 9A and 9B must be lowered by 11 times the height of the cylinder 11 from the camshaft 6 as shown in FIG.

The height of the valve head 9B is lower than the height of the valve head of the exhaust valve 1 shown in FIG. 1 by 11-11.

Further, the spring seats of the intake valves 9A% and 9B are arranged as low as the spring seats of the exhaust valve 1, such as 124-IJ3, to the same extent as lj-12.

Therefore, in the valve train of the present invention, compared to the conventional one, the valve train has higher rigidity and can operate at higher speeds, and although it is a three-valve internal combustion engine, its valve arm chamber is compact. This has the advantage of being able to reduce costs, provide durability, and provide high speed and high output.

The present invention can be effectively applied to a three-valve gasoline engine or a tea cell fuel internal combustion engine.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the main part showing the exhaust valve driving part of a valve train of a conventional overhead cam type internal combustion engine, and FIG. 2 is a valve of a valve train according to an embodiment of the present invention. 3 is a plan view of the inside of the valve arm chamber showing the valve train system shown in FIG. 2, and FIG. 4 is a main part showing the driving parts of the two intake valves shown in FIG. 2. FIG. 1...Exhaust valve, 2...Cap, 6...Camshaft,
4... Exhaust cam, 5... Cylinder head, 9A,...
9B...Intake valve, 10...Intake cam, 11...
Bridge, 11A...flat part. Agent: Patent Attorney Makoto Ogawa − Patent Attorney: Ken Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] In a three-valve internal combustion engine with one cylinder per cylinder, two intake valves and one exhaust valve, a camshaft with an intake cam and an exhaust cam is provided in the cylinder head, and the two intake valves can be opened and closed simultaneously. and is characterized in that a bridge for operating the intake valve is provided at the upper center thereof and has a flat surface that can come into contact with the intake cam, and a cap that can come into contact with the exhaust cam is provided above the valve head of the exhaust valve. Valve train system for internal combustion engines.