JP3311818B2 - Valve train structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for driving a valve for opening and closing three intake valves or exhaust valves with one cam in an internal combustion engine.

[0002]

2. Description of the Related Art In a conventional internal combustion engine, the upper limit of the number of valves per cylinder is four, and no more valves are required, and as shown in FIG.
2 comes into contact with an upper abutment 33, and two valves (an intake valve or an exhaust valve) 34 are operated via a valve bridge 30 whose operating direction is guided by a bridge guide 31 provided on the upper surface of the cylinder head. Was configured to be.

[0003]

However, in the conventional internal combustion engine, two valves are driven by one cam and four valves are provided per cylinder. However, in order to improve the maximum output, There is a possibility that the number of valves may further increase, and an internal combustion engine having a more valve structure is desired. Therefore, the present invention
Effective use of the limited space above the cylinder head, six valves are arranged per cylinder, and three cams are driven by one cam, making the internal combustion engine capable of improving the maximum output. The purpose is to do.

[0004]

Means for Solving the Problems As means for solving the above problems, the present invention relates to an internal combustion engine,
The upper part of three intake valves or exhaust valves (5), (5), and (5) is supported by a valve bridge (2) having a substantially triangular shape in plan view,
Guide portion of cylindrical shape for supporting the valve (5) at the bottom center of the valve bridge (2) and (2a) provided, said guide section (2
a) is inserted into a bridge guide portion (1a) provided on the upper surface of the cylinder head (1) , and the guide portion (2a) is
Valve spring (9) is interposed between guide parts (1a)
Up the valve bridge 2 and the valves (5), (5) and (5).
Slidable up and down while biasing the cam (4
a) is arranged on the side of the valve bridge (2), and the above-mentioned valve arm (3) is arranged above with one cam (4a) .
Driving the valve bridge (2) to drive the three valves (5)
(5) It is configured to open and close (5) .

[0005]

Next, the operation will be described. A cylindrical guide portion 2a provided at a valve support portion at the lower center of a valve bridge 2 supporting three valves (intake or exhaust valves) 5,... Is inserted into a bridge guide portion 1a provided on the upper surface of the cylinder head 1 so as to be slidable in the vertical direction, so that the vertical movement of the valve bridge 2 can be performed smoothly. Can be simultaneously driven.

[0006]

Next, an embodiment of the present invention will be described. FIG. 1 is a side sectional view showing an embodiment of a valve operating structure of an internal combustion engine according to the present invention, FIG. 2 is a side sectional view of a valve bridge 2, and FIG.
FIG.

In FIG. 1, FIG. 2 and FIG.
The cylinder head 1 is mounted and fixed on the upper surface of the cylinder block provided with the cylinder head 1.
On the upper surface of the valve bridge 2, the valve bridge 2
The valve arm 3 and the camshaft 4 and the like are disposed on the sides of the valve arm 3 and are covered with a valve arm chamber cover 10. The valve bridge 2
Is formed in a substantially fan-like shape in a side view and in a substantially triangular shape in a plan view, and has a lower portion guided by a valve guide 15 for opening and closing an intake port or an exhaust port provided in the cylinder head 1. Individual valves (intake or exhaust valves) 5.5
Are supported, and the top of the valve 5.
.., A fitting 7 to which a head of an adjuster bolt 6 screwed to one end of the valve arm 3 abuts is fitted.

[0008] A cylindrical valve bridge guide 2 a is formed in a valve support at the lower center of the valve bridge 2, and the valve bridge guide 2 a is formed on a cylinder formed on the upper surface of the cylinder head 1. It is inserted into the cylinder head bridge guide portion 1a having the shape. A valve spring 9 is provided in the cylinder head bridge guide portion 1a and the valve bridge guide portion 2a, and the valve spring 9 is attached by compression between the spring receiver 8 and the cylinder head 1. With spring force,
Are urged to be in the closed position.

The valve arm 3 is rotatably supported by a valve arm shaft 13, the adjuster bolt 6 is screwed at one end, and an engaging portion 14 is provided at the other end to contact the outer periphery of the cam shaft 4. Yes,
By the action of the cam 4a of the cam shaft 4, the cam shaft 4 rotates up and down,
The valve bridge 2 is pressed downward via the adjuster bolt 6 so that the valves 5, 5,. The point of force of the valve arm 3 is located at the position of the approximate center of gravity C of the three valves 5, 5,.
The pressing force is distributed in a well-balanced manner, and the pressing force and the urging force of the valve spring 9 are combined so that the valve bridge guide portion 2a is appropriately slid on the cylinder head bridge guide portion 1a. Are configured to operate smoothly in the vertical direction.

In this embodiment, six valves 5, 5,... Configured as described above are provided for each cylinder 11, and three valves 5, 5,. · It is configured to drive. That is, three intake valves and three exhaust valves are provided, and three valves 5, 5,... Can be simultaneously driven via the cam 4a, the valve arm 3, the valve bridge 2, and the like. Have been. Alternatively, a configuration in which three intake valves are provided and two exhaust valves are provided is also possible.

[0011]

The present invention is configured as described above.
The following effects are obtained. That is, from that place the valve in the guide portion of the valve bridges fitted to the bridge guide portion provided in the cylinder head top surface, and as it can be used effectively limited the cylinder head top positions, the cam shaft 4 Is on the side of the valve bridge 2
Because it is located, it can be lowered without protruding upward,
In addition, since the guide portion 2a of the valve bridge 2 is formed in a cylindrical shape, the vertical movement of the valve bridge 2 can be smoothly performed, and three valves 5, 5,...
Can be driven at the same time, so that the maximum output of the compact internal combustion engine can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a valve train structure for an internal combustion engine according to the present invention.

FIG. 2 is a side sectional view of the valve bridge 2.

FIG. 3 is a plan view of the same.

FIG. 4 is a side sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 1a Cylinder head bridge guide part 2 Valve bridge 2a Valve bridge guide part 3 Valve arm 4 Camshaft 5 Valve

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 1/26

Claims (1)

(57) [Claims] In an internal combustion engine, three intake valves or exhaust valves are provided by a valve bridge (2) having a substantially triangular shape in a plan view.
(5) (5) The valve bridge supporting the upper part of (5),
(2) the guide portion of the cylindrical supporting the valve (5) at the bottom center of (2a) is provided in, fitted the guide portion (2a) to the bridge guide portion provided in the cylinder head (1) upper surface (1a) The guide portion (2a) and the bridge guide portion (1a).
The valve spring (9) is interposed between the valve
The ridge 2 and the valves (5), (5) and (5) are slidable vertically while urging them upward, and the cam (4a) is
Arranged on the side of the jig (2) and upward with one cam (4a)
The valve bridge via a valve arm (3) arranged at
(2) is driven to open the three valves (5), (5) and (5).
Valve operating structure for an internal combustion engine, characterized by being configured so as to close.