JPS61275545A - Tappet valve device in internal combustion engine - Google Patents

Abstract

PURPOSE:To support the rolling arm for intake valve reliably by inclining the axis of cover tube for ignition plug against the axis of cylinder bore such that it will pass between the rolling arm shaft for intake valve and the spring of intake valve. CONSTITUTION: The axes 16, 17 of an intake valve 12 and an exhaust valve 13 are inclined in the opposite directions by proper angles theta1, theta2 against the axis 18 of cylinder bore 2 and arranged in V-type as a whole. Single common cam shaft 19 is journaled in parallel with the longitudinal center line of engine between said valves 12, 13. The rolling arm shafts 20, 21 for intake and exhaust valves are arranged in parallel with the cam shaft 19. Here, the axis 30 of cover tube 29 for mounting an ignition plug 8 onto the cylinder head 3 is inclined by proper angle against the axis 18 of cylinder bore 2 such that it will pass between the rolling arm shaft 20 for intake valve and the spring 14 of intake valve 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve train for an internal combustion engine in which two intake valves and two exhaust valves are provided for each cylinder.

[Conventional technology]

In recent internal combustion engines, in order to improve output etc., each cylinder has two intake valves and two exhaust valves, and these two intake valves and two exhaust valves are operated to open and close. In the case where the camshaft is made into one camshaft and placed between the intake valve and the exhaust valve, the camshaft is divided into two camshafts, one for the intake valve and the other for the exhaust valve. It has the advantage of being simpler in structure compared to the original version.

However, arranging one common camshaft for two intake valves and two exhaust valves in the area between the intake valve and the exhaust valve in this way prevents the electrode part of the ignition plug from burning. The problem is that the camshaft makes it difficult to center the chamber.

Therefore, Japanese Patent Application Laid-Open No. 54-125315 as a prior art proposes two intake valves and two exhaust valves in one cylinder, and a common camshaft for both intake valves and both exhaust valves. In an internal combustion engine disposed between an intake valve and both exhaust valves, the pivoting portion of the swinging arm for each of the intake valves has a cantilever structure, that is, both swinging arms for both intake valves are pivotably supported. dividing the swinging arm shaft at a part between the two swinging arms to form a space in this part;
We propose to move the electrode part of the ignition plug closer to the center of the combustion chamber by tilting the axis of the cover tube with respect to the axis of the cylinder bore so that the cover tube for installing the ignition plug is located in this space. ing.

[Problem that the invention seeks to solve]

However, in order to bring the ignition plug closer to the center of the combustion chamber, the swing arm shaft that pivots both swing arms for both intake valves is separated at the part between the two swing arms. Using a cantilevered structure for the pivot portion of the swinging arm will cause distortion in the swinging motion of both swinging arms, which will increase power loss and will cause both swinging arms to have a cantilevered structure. There was a problem in that the diameter of the swinging arm shaft, which is pivotally supported in a holding manner, had to be considerably thickened.

The present invention aims to solve this problem.

[Means for solving problems]

For this reason, the present invention provides two intake valves and two exhaust valves for one gas oil so as to be inclined in a V-shape with respect to the axis of the cylinder bore, and between the two intake valves and the two exhaust valves. A common camshaft for these intake valves and exhaust valves is disposed at a location, while two swing arms for each of the intake valves and two swing arms for each of the exhaust valves,
A cover pipe for installing a spark plug is pivotally supported on each of the swinging arm shafts arranged on both sides of the camshaft in parallel with the camshaft, and a cover pipe for installing a spark plug is provided between the swinging arms for the intake valve. In the internal combustion engine, the axis of the cover tube for the spark plug is
The axis is inclined with respect to the axis of the cylinder bore so as to pass through a portion approximately in the middle between the swing arm axis for the intake valve and the spring of the intake valve.

[Action/effect of the invention]

In this way, the axis of the ignition plug and its cover pipe for the cylinder is aligned with respect to the axis of the cylinder bore so that the axis passes approximately halfway between the swinging arm axis for the intake valve and the spring provided on the intake valve. Although the electrode part of the spark plug can be brought closer to the center of the combustion chamber, the swing arm shaft for pivotally supporting the swing arm of each of the intake valves can be moved closer to the center of the combustion chamber. Since there is no need to separate the two swing arms between the two swing arms as in the conventional technology, it is possible to avoid having the two swing arms for the intake valve in a cantilever support structure.

On the other hand, when a cover pipe for an ignition plug is provided between both swing arms for an intake valve, in order to avoid separation of the swing arm shaft that pivotally supports both swing arms, the cover pipe is , located in the part between the springs in both intake valves must increase the distance between both intake valves, and for the same purpose, the cover pipe should be located outside the springs in both intake valves. This means that the width of the cylinder head increases, but the present invention is applicable to the cylinder as described above.

By making the axis of the ignition plug and its cover pipe pass approximately halfway between the swinging arm axis for the intake valve and the spring provided on the intake valve, the distance between the two intake valves can be reduced. This makes it possible to avoid widening of the cylinder head and an increase in the width of the cylinder head.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, l is a cylinder block having a cylinder bore 2 inside, 3 is a cylinder head joined to the top surface of the cylinder block 1, and 4 is a cylinder head movable to the top surface of the cylinder head 3. The valve mechanism chamber 5 is attached so as to be freely deposited (a rad cover is shown for each cylinder, and a piston 6 is provided in the cylinder bore 2 to reciprocate within the cylinder bore 2, and
A vent-roof type combustion chamber 7 is recessed in the lower surface of the cylinder head 3, and an ignition plug 8 is attached to the cylinder head 3 at approximately the center of the combustion chamber 7.

9a and 9b are two intake ports for the one combustion chamber 7, and 10a and 10b are two exhaust ports for the one combustion chamber 7, both intake ports 9a and 9b.
The re-exhaust boats 10a and 10b are defined by a longitudinal centerline 11a passing through the center of the cylinder bore 2 in a plan view of the engine.
and on both sides of the orthogonal center line 11b, which is perpendicular to the longitudinal center line 11a.

A poppet-type intake valve 12 and an exhaust valve 13 are provided at the openings of both intake ports 9a and 9b into the combustion chamber 7, and at the openings of the re-exhaust port 1-102t 10b into the combustion chamber 7.
A stem 12a in each of these valves.

13a are provided on each of the valves so as to protrude into the valve mechanism chamber 5 on the upper surface of the cylinder head 3, and springs 14 and 15 are provided on the stems of each of these valves to hold each valve closed. There is.

In this case, the axis 16 of both the intake valves 12 and the axis 17 of the exhaust valve 13 are inclined in opposite directions by appropriate angles (θ1) and (θ2) with respect to the axis 18 of the cylinder bore 2. The intake valve 12 and both exhaust valves 13 are V-shaped with respect to the axis 18 of the acid cylinder bore 2.

Reference numeral 19 denotes a single camshaft common to both the intake valves 12 and both exhaust valves 13, and the camshaft 19 is located between the intake valve 12 and the exhaust valve 13 in the valve mechanism chamber 5. A swing arm shaft 20 for an intake valve and a swing arm shaft 21 for an exhaust valve are supported in parallel with the longitudinal centerline 11a of the engine, and in the valve mechanism chamber 5 are a swing arm shaft 20 for an intake valve and a swing arm shaft 21 for an exhaust valve. The cylinder head 3 is supported by two bearings 22, 22 on both sides of the cylinder head 3 so as to be parallel to the camshaft 19.

The swing arm shaft 20 for the intake valve has two swing arms 23.23 for each of the intake valves 12, and the swing arm 21 for the exhaust valve has two swing arms for each of the exhaust valves 13. 24.24 is rotatably supported, and in this case, both swinging arms 23 for the intake valve are provided so as to be located outside of the swinging arm 24 for the exhaust valve in a plan view. The two swinging arms 23 for the intake valve have one end attached to the upper surface of the intake valve cam 25.25 on the camshaft 19, and the other end attached to the stem 12 of the intake valve 12 via a clearance adjustment screw 26.
The swinging arms 24 for the exhaust valve are in contact with the upper ends of the exhaust valve cam 2 on the camshaft 19, respectively.
7 and the other end thereof is in contact with the upper end of the stem 13a of the exhaust valve 13 via a gap adjusting screw 28.

Reference numeral 29 denotes a cover tube for attaching the spark plug 8 to the cylinder head 3 from the outside of the cylinder lid cover 4. The axis 18 of the cylinder bore 2 is set at an appropriate angle (θ
3).

In this way, the axis 30 of the cover pipe 29 for attaching the ignition plug is arranged so that the axis 30 passes through a portion approximately in the middle between the swinging arm shaft 20 for the intake valve and the spring 14 of the intake valve 12. By being inclined at an appropriate angle (θ3) with respect to the axis 18 of the cylinder bore 2, the axis 30 of the cover tube 29, and thus the electrode portion 8a of the spark plug 8, can be located at or near the center of the combustion chamber 7. However, it is possible to avoid separating the swinging arm shaft 20 for the intake valve between the two swinging arms 23 and 23 as in the prior art, and also to connect the cover pipe 29 to both the intake valves 12. Increasing the intervalve distance between both intake valves 12 when located between the springs 14, 14 in each, and the cover pipe 29
It is also possible to avoid an increase in the width dimension of the cylinder head 3 when the intake valve 12 is located outside the spring 14 of the intake valve 12.

In this case, a recessed portion 31 is formed on the side surface of the intake valve swing arm shaft 20, and the cover pipe 29 is inserted into this recessed portion 31.
, the length from the swing arm shaft 20 to the gap joint screw 26 in the swing arm 22 will be
Since the length of the cover pipe 29 is shortened by the size in which the cover pipe 29 is fitted into the recessed portion 31, the width of the cylinder head 3 can be reduced. By curving inward to the cover pipe 29, the distance between the two intake valves 12, 12 can be further reduced. Furthermore, a seal ring 32 made of a soft elastic material such as rubber is provided at a portion where the cover tube 29 passes through the rad cover 4 into the cylinder.

In addition, the reference numeral 33.34 in the figure indicates each swing arm 23.23.
．． This is a spring body for pressing 24.24 toward the bearing 22.22.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main parts of the engine, a sectional view taken along line 1-1 in FIG. 2, and FIG.
-n bottom view, and FIG. 3 is an enlarged sectional view taken along the mm line of FIG. 1. 1... Cylinder block, 2... Cylinder bore,
3... Cylinder head, 4... Rad cover to cylinder, 5... Valve train chamber, 7... Combustion chamber, 8... Spark plug, 9a, 9b... Intake boat, 10a, 10b・
...Exhaust port, 12...Intake valve, 13...Exhaust valve, 14.15...Spring, 19...Camshaft, 20.2
1... Swinging arm axis, 23.24... Swinging arm,
29...Cover tube.

Claims (1)

[Claims] (1) Two intake valves and two exhaust valves in one cylinder,
The cylinder is provided so as to be inclined in a V-shape with respect to the axis of the cylinder bore, and a common camshaft for the intake valves and the exhaust valves is disposed between the intake valves and the exhaust valves. Two swing arms for each of the valves and two swing arms for each of the exhaust valves are pivotally supported on respective swing arm shafts disposed on both sides of and parallel to the cam shaft. , and in an internal combustion engine in which a cover pipe for mounting a spark plug is disposed in a portion between both swing arms for the intake valve, the axis of the cover pipe for the spark plug is set to the above-described axis. 1. A valve operating device for an internal combustion engine, characterized in that the swinging arm shaft for the intake valve is inclined with respect to the axis of the cylinder bore so as to pass through an approximately intermediate portion between the spring of the intake valve.