JPS6341607A - Valve system for engine - Google Patents

Abstract

PURPOSE:To aim at reduction in the overall height of an engine, by driving a valve to be installed at the tilted side of a cylinder center shaft of the engine being mounted at a tilt directly by a cam, while driving a valve to be situated at the opposite tilted side by the cam via a push rod. CONSTITUTION:Both suction and exhaust valves 9 and 10 are installed each symmetrical position in reference to a center axis l1 of a cylinder being tilted as far as the specified angle to an axis l2 of an engine 1. And, in this suction valve 9, a tappet 13 is engaged with its valve stem 9a, and this tappet 13 is made contact with a cam 15 on a suction valve camshaft 14 supported on a cylinder head 3 for engagement whereby the suction valve 9 is made possible to be directly driven. In addition, the exhaust valve 10 is made drivable by rotation of a cam 19 on the camshaft situated in a cylinder side part on an engine axis 12 via a plunger 20, a push rod 21 and a rocker arm 23. With this constitution, a quantity of projection to the upper part is made reducible, thus the overall height of the engine is made so as to be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve train for an engine, and particularly to an engine that is mounted on a vehicle with a cylinder in an inclined state.
The present invention relates to a so-called double overhead camshaft type (hereinafter referred to as DOHC) valve operating system, which is provided with camshafts above a cylinder for driving intake and exhaust valves.

(Prior art) DOH in which each camshaft is placed in the space above the cylinder head to drive the intake and exhaust valves of the engine.
The C-type valve train has been well known. Also,
Engines in which the cylinders are mounted in an inclined state, such as the so-called ■-type engine, are also known. For example, JP-A-57-1
Publication No. 40507 describes ■ equipped with a DOHC type valve mechanism.
A type of engine is disclosed in which the intake and exhaust valves are driven by cams formed on respective camshafts disposed above the intake and exhaust valves.

(Problems to be Solved) In the structure disclosed in JP-A-57-140507, the cylinders are arranged in an inclined manner so as to face each other in order to suppress the height of the engine. but,
In this structure, the D OHC with two camshafts
Since the type valve mechanism is built into the cylinder head, there is no difference in the center axis of the cylinder of the valve mechanism. There is a problem in that the part located at 11 protrudes to one side, making it impossible to effectively suppress the height of the engine.

(Means for solving the problem) The present invention is constructed by taking into account the above circumstances, and
+-In an engine equipped with an IC type valve train and whose cylinders are arranged in an inclined state, an engine that can suppress the upward protrusion of the valve train as much as possible, thereby preventing the overall height of the engine from becoming unduly large. The purpose is to provide valve train. In the valve train of the present invention, the valve located below the inclined side of the cylinder center axis is driven by a cam of the first camshaft provided in the cylinder head, and the valve is positioned below the slope side of the cylinder center axis. The valve located on the opposite inclined side, that is, above, is driven via a push rod by a cam of a second cam shaft provided below a symmetrical position of the power shaft with respect to the cylinder center axis. The present invention can be most effectively applied to a ■ type child cylinder engine, but is not necessarily limited thereto, and can be applied to any type of engine in which cylinders are mounted in an inclined state.

(Effects of the Invention) According to the present invention, the camshaft of the valve train for driving the valve located on one side of the central axis of the inclined cylinder is connected to the camshaft of the valve train located below the central axis of the cylinder. It is arranged in a space above the engine below the symmetrical position of the camshaft with respect to the cylinder center axis. As a result, since the camshaft is not disposed in the symmetrical position described in item 1, the amount of upward protrusion can be reduced, and the height of the engine can be suppressed. By reducing the height of the engine in this way, the engine room can be configured compactly.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The engine to which the valve train of this example is applied is a type engine, and the figure shows a two-part structure of the engine 1 in cross section.

The valve train 2 of this example is designed to be incorporated into the second part of the cylinder head 3 of the engine 1.

Since the engine 1 of this example is a type engine, the central axis 11 of the cylinder is inclined at a predetermined angle with respect to the vertical line of the axis β2 of the engine 1. The cylinder head 3 is formed with an intake passage 5 and an exhaust passage 6 that communicate with the combustion chamber 4.
It communicates with the combustion chamber 4.

These ports 7.3 have an intake valve 9 and an exhaust valve 10.
are combined respectively. These intake and exhaust valves9.10
are arranged symmetrically with respect to the central axis β1, and their valve stems 9a and loa are similarly supported by valve guides 9b, 10b and extend symmetrically upward with respect to the central axis 11 of the cylinder.

A spring holder 12 for holding down a spring 11 is attached to the tip of the valve stem 9a of the intake valve 9.

A tappet 13 is engaged with a valve stem 9a of the intake valve 9, and a cam 15 formed on an intake valve camshaft 14 abuts and engages with the tappet 13.

Furthermore, a spring retainer 17 for compressing the spring 16 is also attached to the valve stem 10af of the exhaust valve 10. The driving camshaft 13 of the exhaust valve 10 is located at the center of the two banks and at the side of the cylinder on the engine axis p2.

In this example, the exhaust valve camshaft 18 is common to the exhaust valves 10 of the two banks of cylinders, so this camshaft has the exhaust valves 18 of all the cylinders.
A cam is formed corresponding to 0.

A cam 19 formed on the camshaft 18 is in contact with a plunger 20 that is slidably supported by the cylinder head 3. The plunger 20 is configured to engage, via a push rod 21, with one end of a rocker arm 23 attached to a rocker shaft 22 that is disposed approximately symmetrically to the intake valve camshaft 14 with respect to the central axis β1.

The other end of the rocker arm 23 is engaged with the tip of the valve stem 10a. With this structure, the exhaust valve 10 is driven to open and close by rotation of the cam 19 via the plunger 20°, the push rod 21, and the rocker arm 23.

A cylinder head cover 24 that covers the valve train 2 is attached to the cylinder head 3 . Further, an ignition plug 25 is attached to the cylinder head 3 substantially along the central axis p1 so that its tip protrudes into the combustion chamber 4.

In the second configuration, unlike the structure of the conventional DOHC type valve train 2, the camshaft 18 for the exhaust valve 10 is located at a symmetrical position to the camshaft 14 for the intake valve 9 with respect to the central axis β1 of the cylinder. It is located below the symmetrical position on the engine axis β2'2.

And, at the symmetrical position of the camshaft 14 for the intake valve,
Only a rocker arm mechanism with a small amount of upward protrusion is arranged. Therefore, compared to the structure of a tilted engine incorporating a conventional D OL (C type valve train), the upward protrusion can be reduced and the overall height of the engine can be suppressed.As a result, the engine room can be made compact. can be formed into

[Brief explanation of the drawing]

The figure is a top sectional view of an engine according to an embodiment of the valve train of the present invention. 1...Engine, 2...Valve train, 3
...Cylinder head, 4...Combustion chamber, 5
...Intake passage, 6...Exhaust passage, 7.
...Intake port, 8...Exhaust port, 9
...Intake valve, 10...Exhaust valve, 11.
... Spring, 12 ... Spring holder, 13.
... Tappet, 14 ... Intake valve camshaft, 15 ... Cam, 16 ... Spring, 17 ... Spring holder, 18 ... ... Exhaust valve camshaft, 19... Mouth... Cam, 20...
・Plunger, 21...Push rod, 22
...Rocker shaft, 23...Rocker arm, 24...Cylinder head cover, 25...
...Spark plug.

Claims (1)

[Claims] In a valve train for an engine in which the cylinder is installed in an inclined state, the valve located on the inclined side of the cylinder center axis is
The valve is driven by a cam of a first camshaft provided in the cylinder head, and the valve located on the opposite inclined side of the cylinder central axis is located below the symmetrical position of the first camshaft with respect to the cylinder central axis. A valve train for an engine, characterized in that it is driven by a cam of a second camshaft provided in the engine via a push rod.