JPS6149114A - Valve moving mechanism of four-stroke internal-combustion engine - Google Patents

Abstract

PURPOSE:To adjust a valve clearance at one position of a lifter by arranging an equalizer between a lifter driven by a cam and the valve rod tips of multiple intake valves, driving the equalizer at the position of the center of gravity of the valve rod tip, and forming each contact point into a spherical surface. CONSTITUTION:There intake valves 7 are provided per cylinder and are driven by a cam 15a. An equalizer 12 is arranged between a lifter 13 driven by the cam 15a and the valve rods 7a of the intake valves 7, and the lifter 13 drives the equalizer 12 at the position of the center of gravity among tip positions of three valve rods 7a. The contact point of the lifter 13 and the equalizer 12 and the contact point of the equalizer 12 and the valve rod tip 17 are spherical surfaces 18, 19. Accordingly, the clearance of the valve can be adjusted with a shim 14 at one position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a valve mechanism for a four-stroke internal combustion engine.

[Prior art]

In order to reduce the intake and exhaust resistance of a four-stroke internal combustion engine and improve engine performance, there are some models that have fewer intake and exhaust valves per cylinder (or more than one of them). When the number of cams is plural, the number of lifters in the valve train and the number of cams on the camshaft are increased, resulting in problems such as an increase in the total weight of moving parts and an increase in the number of man-hours required for machining the cams.

In order to solve this problem, there is a system in which a single lifter is used in common for a plurality of valves, and the single lifter is used to operate a plurality of valves. (Refer to Japanese Unexamined Patent Publication No. 186010/1983). However, although this valve operating mechanism solved the above-mentioned problems, the clearance adjustment caused by manufacturing variations in the plurality of valves had to be adjusted for each valve, and problems still remained.

[Purpose of the invention]

The object of the present invention is to provide a four-stroke internal combustion system that takes advantage of operating multiple valves with a single lifter, while also allowing clearance adjustment of multiple valves to be performed at one location at the same time, without having to adjust the clearance for each individual valve. Our objective is to provide a valve mechanism for engines.

[Structure of the invention]

In order to achieve the above object, the valve operating mechanism of the present invention has a plurality of at least one of intake valves and exhaust valves per cylinder, and opens and closes the plurality of valves simultaneously by a cam via a single lifter. In a four-stroke internal combustion engine, the above 1 ([1
One equalizer is interposed between the lifter i1 and the valve stem ends of the plurality of valves, and the lifter and the equalizer are arranged so that the axis of the lifter is the center of gravity of the figure connecting the plurality of valve stem ends. The equalizer is rotatably engaged through a spherical surface in a matched state, and the equalizer and a plurality of valve stem ends are rotatably engaged through the spherical surfaces. It is.

[Embodiments of the invention]

The present invention will be explained below with reference to embodiments shown in the drawings.

In the embodiment shown in FIGS. 1 to 4, 1 is a cylinder body, 2 is a cylinder head, and 3 is a cam carrier. A piston 5 is fitted into the cylinder 4 in the cylinder body 1 so as to be able to reciprocate, and a combustion chamber 6 is formed in the cylinder head 2 in correspondence with the upper part of the cylinder 4. The above combustion chamber 6
is provided with three intake valves 7, 7.7 and two exhaust valves (not shown). The combustion chamber 6 communicates with an intake passage 8 via an intake valve 7, and with an exhaust passage 9 via an exhaust valve.

The above three intake valves? , 7.7, the valve rods 7a, 7a, 7a pass through the cylinder head 2 upwardly, and a spring 11 is interposed between the spring receiver 10 provided at the upper part and the upper surface of the cylinder head 2, respectively. The spring 11 always biases the intake valve 7 in the valve closing direction.

One equalizer 12 is placed on the upper ends of the three valve stems 7a, 7a, 7a, and one cylindrical lifter 13 is placed on the upper center thereof. A shim 14 is attached to the top surface of the lifter 13.
is attached to the drive camshaft 15 via this shim 14.
The cam 15a is in contact with the cam 15a. Therefore, the camshaft 15
, the lifter 13 is pushed down, and the three valve rods 7a + 7a, 7a are pushed down simultaneously via the equalizer 12, and the three intake valves 7. 7. 7 is designed to open.

16 is a driving camshaft on the exhaust valve side (not shown).

The upper ends of the three valve stems 7a, 7a, 7a are machined into a spherical shape, and the spherical ends are rotatably fitted into flat-bottomed engagement holes 17 provided at 3 f1 MI on the lower surface of the equalizer 12, respectively. I am making it match. On the other hand, the lifter 13 has three valve stems 7a, 7a, 7a on the upper surface side of the equalizer 12.
At the center of gravity of the triangle formed by connecting the upper ends of the lifter 1
It is placed so that the axes of 3 are aligned. Moreover, a concave spherical seat 18 is formed at the lower end of the lifter 13, and the seat 18 is engaged in line contact with a convex spherical protrusion 19 formed on the equalizer 12 side, making it rotatable. ing.

The seat 18 having a concave spherical surface and the protrusion 19 having a convex spherical surface are the fifth
As shown in the figure, a convex spherical protrusion 18'' is formed on the lower end side of the lifter 13, and a concave spherical seat 19' having a radius larger than the above protrusion 18° is formed on the equalizer 12 side, so that they are in point contact with each other. Alternatively, one may be a convex or concave spherical surface and the other may be a concave or convex conical surface.

6 to 8 show an embodiment in which two intake valves 7 are provided per cylinder.

In this case, the figure connecting the upper ends of the two valve stems 7a, 7a is a straight line segment, and the center thereof is the center of gravity. Therefore, on the equalizer 12, the lifter 13 is arranged so that its axis coincides with the center point of the line segment, and as in the above embodiment, the concave spherical seat 18 of the lifter 13 and the convex spherical seat 18 on the equalizer 12 side are aligned. Through line contact with the protrusion 19, it is rotatably engaged.

Further, in this embodiment, the point contact engagement position of the spherical upper end of the valve stem 7a with the engagement hole 17 of the equalizer 12 is the line contact engagement position between the protrusion 19 between the equalizer 12 and the lifter 13 and the seat 18. The relationship is such that it is located above the alignment position by a distance felt l.

As described above, in the valve operating mechanism of each of the above embodiments, each end of the plurality of valve rods 7a and one equalizer 12 are rotatably engaged with each other via a spherical surface, and the equalizer 12 and one equalizer 12 are rotatably engaged with each other through a spherical surface. The lifters 13 are rotatably engaged via spherical surfaces with the lifter axis aligned with the center of gravity of the figure connecting each end of the plurality of valve rods 7a. Therefore, even if there is a clearance due to manufacturing variations between multiple valves, by adjusting the shim 14 at the lifter 13, the spherical engagement at the two locations will automatically rotate in the direction that eliminates the clearance. The entire valve can be adjusted at once.

In addition, although the above-mentioned embodiment explained the case where a plurality of intake valves were provided per cylinder, the exhaust valve can also have a similar configuration.

〔Effect of the invention〕

As described above, the valve train structure of the present invention has a plurality of at least one of intake valves and exhaust valves per cylinder, and opens and closes the plurality of valves simultaneously by a cam via one lifter. In the stroke internal combustion engine, an equalizer is interposed between the one lifter and the valve stem ends of the plurality of valves,
The lifter and the equalizer are rotatably engaged via a spherical surface with the axis of the lifter aligned with the center of gravity of the figure connecting the ends of the plurality of valve stems, and the equalizer and the plurality of equalizers are Since the ends of the valve stem are rotatably engaged through their respective spherical surfaces, the entire valve can be adjusted by adjusting the clearance caused by manufacturing variations between the valves at just one location on the lifter. can be adjusted at the same time.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the main parts of a four-stroke internal combustion engine equipped with a valve mechanism according to an embodiment of the present invention, and FIG.
3 is a view in the direction of the I[[-I[I arrow in FIG. 1, FIG. 4 is a longitudinal cross-sectional view of the four-stroke internal combustion engine, and FIG. 6 is a longitudinal sectional view showing the main parts of a four-stroke internal combustion engine equipped with a valve mechanism according to another embodiment of the present invention, and FIG. 7 is a longitudinal sectional view showing the engaging part of FIG. ■-■ arrow view, FIG. 8 is a ■-■ arrow view of FIG. 6... Combustion chamber, 7... Intake valve, 7a... Valve rod, 10... Spring receiver, 11... Spring,
12... Equalizer, 13... Lifter, 1
4...Shim, 15...Camshaft, 15a...Cam, 18...Concave spherical seat, 18''...Convex spherical protrusion, 19...Convex spherical protrusion, 19 ”...
・Concave spherical seat.

Claims (1)

[Claims] In a four-stroke internal combustion engine in which at least one of a plurality of intake valves and exhaust valves per cylinder is provided, and the plurality of valves are simultaneously opened and closed by a cam via one lifter, the one lifter and the plurality of An equalizer is interposed between the valve stem ends of the valve, and the lifter and the equalizer are arranged in a spherical shape with the axis of the lifter aligned with the center of gravity of the figure connecting the plurality of valve stem ends. A valve mechanism for a four-stroke internal combustion engine, characterized in that the equalizer and a plurality of valve stem ends are rotatably engaged through spherical surfaces. .