JPS6220607A - Valve mechanism of internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a valve mechanism for an internal combustion engine, and more specifically, in a valve mechanism using a sealed oil tappet, the oil tappet has a short operating stroke. In addition, the boot that defines the reservoir chamber of the oil tappet is less susceptible to the effects of heat, and it is also possible to prevent oil from being applied to the boot, thereby improving the operational stability and durability of the oil tappet. Regarding valve train mechanisms.

"Prior Art" As is well known, a camshaft is provided at the top of the cylinder head, and the rocker arm is driven by the camshaft.
Accordingly, there is a type of valve operating mechanism that opens and closes an intake valve or an exhaust valve that is engaged with a rocker arm.

One such type of valve operating mechanism is, for example, one in which the lower end of the rocker arm is supported on the cylinder head body side via a sealed oil tappet, and the rocker arm is brought into contact with the upper center of the rocker arm in the lengthwise direction. There is a so-called end pivot type in which a camshaft is arranged and an intake valve or an exhaust valve is arranged so as to contact the other end of the rocker arm.

"Problems to be Solved by the Invention" The present invention attempts to solve the following problems in the above-mentioned valve train mechanism.

That is, in the above-described valve mechanism, (a) the oil tappet is brought into contact with one end of the rocker arm;
Since the intake valve or exhaust valve is arranged so that it is in contact with the other end, if a gap occurs between the intake/exhaust valve and the rocker arm or between the camshaft and the rocker arm due to thermal expansion, wear, etc. In order to eliminate the gap, the oil tappet must extend by an amount equivalent to the gap, and there is a problem that the operating stroke of the oil tappet is large.

(b) Since the oil tappet is located on the lower side of the rocker arm, that is, on the combustion chamber side, there is a boot that forms the reservoir chamber for the oil tappet (usually, this boot is made of a rubber material that is easily affected by heat). ) is located near the top of the combustion chamber, and there is a problem that the boot may deteriorate early due to heat, requiring frequent maintenance.

Furthermore, (c) since the boot is placed under the rocker arm, which is a place where oil splashes are likely to hit, there is a risk that oil splashes will hit the side wall of the boot and penetrate there and enter the reservoir chamber. In this case, there is a problem in that the boots bulge outward and become abnormally deformed.

[Means for Solving the Problem] The present invention aims to provide a valve mechanism for an internal combustion engine that can effectively solve the above-mentioned conventional problems without impairing the functions of the oil tappet. It is characterized by a valve mechanism in which a camshaft is provided at the top of the cylinder head, and the rocker arm is driven by the camshaft to open and close the intake valve or exhaust valve. The upper part is supported by the cylinder head body side via a sealed oil tappet, and the camshaft is arranged at the bottom of one end of the rocker arm, and the intake valve or exhaust valve is arranged at the bottom of the other end of the rocker arm. A high pressure chamber is defined on the rocker arm side of the type oil tappet,
A reservoir chamber surrounded by an elastic boot is formed on the side of the cylinder head body supporting portion of the oil tappet, and furthermore, a reservoir chamber surrounded by an elastic boot is formed on the outer periphery of the oil tappet and extends from the cylinder head body side and the boot is connected from the high pressure chamber side. A partition wall is provided, and an annular oil groove is provided on the sliding surface of the partition wall against the oil tappet, and an oil supply means is connected to the oil groove.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a vertical cross-sectional view of a so-called SOHC internal combustion engine with a single camshaft installed at the top of the cylinder head, Figure 2 is an enlarged cross-sectional view of a part of it, and Figure 3 is an arrow in Figure 1. ■
It is a figure seen from the direction.

In FIG. 1, reference numeral 1 indicates a cylinder head, and this cylinder head 1 is composed of a cylinder head body 2 and a head cover 3 disposed above the cylinder head body 2. As shown in FIG. The camshaft 6 is disposed approximately in the upper center of the cylinder head l between the intake valve 4 and the exhaust valve 5. The camshaft 6 is connected to the crankshaft via a chain, and is spaced 1/2. It is designed to be rotated at a speed of .

Further, 7.8 each indicates a rocker arm, and the rocker arm 7.8 is supported on the cylinder head main body side through a sealed oil tappet 9, IO at the approximately central upper part in the longitudinal direction. It is designed to be operated by swinging with the part as a fulcrum. This rocker arm 7.8 is oscillated by the rotation of the camshaft 6 when the power shaft 6 disposed in contact with the lower part of one end is rotated, and is brought into contact with the lower part of the other end. The intake valve 4 or the exhaust valve 5 that is in contact with the valve is opened or closed.

1] is a block provided integrally with the cylinder head body (this block functions as a partition wall that partitions the oil tappet into upper and lower parts as described later), and this block 11 has a block that penetrates in the vertical direction in the figure. A hole 12 is provided,
The oil tappet °(+(to)) is slidably fitted into this hole 12.

Further, a press plate 13 is bolted to the upper part of the block 11, and the press plate 13 presses and supports the upper end of the oil tappet 9 (10). In addition, the block 11 is provided with an oil reservoir 14 threads, and the oil reservoir 1°4 is connected to an annular ring provided on the sliding surface of the oil tappet 9 (10) of the block 11 through a hole 15 passing through the block 11. It communicates with the oil groove 16. Note that an opening 17 is provided in the holding plate 13 at a location corresponding to the oil reservoir 14 (see Fig. 3), so that a portion of the oil droplets floating in the cylinder head l flows into the oil reservoir I4.
It is designed to accumulate inside. In other words, oil sump I
4 and the hole 15 constitute an oil supply means for supplying a part of the oil in the cylinder head 1 to 1l16.

To explain the oil tappet 9, the reference numeral 21 in FIG. 22 is slidably fitted. A high pressure chamber 23 is formed between the plunger body 21 and the plunger 22, and
The plunger body 21 is urged downward in the figure by a spring 24 disposed between the plunger body 21 and the plunger 22.

The upper part of the plunger 22 protrudes from the plunger body 21, and one side of a boot 25 made of an elastic material is liquid-tightly fitted to the outer periphery of the upper end. Closely fitted. A reservoir chamber 26 is formed between the boot 25 and the plunger 22, and the reservoir chamber 26 has a hole 27 passing through the plunger 22 in the horizontal direction in the drawing and a hole 28 passing through the plunger 22 in the vertical direction. The plunger 22 is connected to the high pressure chamber 23 through the holes 27, 28, and a hole 29 provided parallel to the lower side of the hole 27. It also communicates with the annular groove 30.

A ball 31 functioning as a check valve is housed in a cage near the opening of the high pressure chamber 23 to the hole 28 .

In this (upper δ) oil tappet 9 (10), a high pressure chamber 23 is formed on the rocker arm side, and a reservoir chamber 26 is formed on the opposite side from the rocker arm (upper side in the figure). The boot 25 forming the reservoir chamber 26 provided at the upper part of the oil tappet 9 (lO) is housed in a chamber 32 formed by the block ll and the holding plate 13, and is completely separated from the others. Note that the chamber 32 is a breather hole 33 provided in the presser plate 13.
It is communicated with the outside via.

Next, the operation of the above-mentioned valve train mechanism will be explained.

If a gap is to occur between the rocker arm 7 (8) and the camshaft 6 or between the rocker arm 7 (8) and the intake/exhaust valve 4 (5), the spring 24
The plunger body 21, which is urged downward by the force, moves downward to absorb this gap. Also, plunger body 2! With the downward movement of the hole 2, the oil in the reservoir chamber 26 is
7.28 into the high pressure chamber 23. At this point, even if a compressive force is applied to the oil tappet 9 (10) by the operating force of the t-valve cam unit integrally installed on the camshaft, the oil flows into the high pressure chamber 23 and a large amount of oil flows into the ball 3.
1 prevents the oil from flowing in the opposite direction, the oil tappet 9 (10) remains rigid at an appropriate length and is not compressed, allowing the oil tappet 9 (10) to absorb the operating force of the valve drive cam section through the rocker arm 7 (8).・Transmitted to the exhaust valve.

Furthermore, when the plunger body 21 moves up and down relative to the plunger 22, the volume of the high pressure chamber 23 changes;
The amount of change is absorbed by the change in volume of the reservoir chamber 26 due to the deformation of the boot 25.

Furthermore, in the above valve mechanism, the oil tappet 9 (10)
is placed above the rocker arm 7 (8),
In addition, by arranging the boot 25 above the oil tappet 9 (10), the boot 25, which is easily affected by heat, can be placed as far away from the combustion chamber as possible, thereby increasing the durability of the boot 25. Therefore, the durability of the oil tappet 9 (10) can be increased.

In addition, in the above-mentioned valve mechanism, since the upper center of the rocker arm 7 (8) is supported by the oil tappet 9 (10), the rocker arm 7 (8) and a part of the camshaft 6, or the rocker arm 7 (8) Even when a gap occurs between the oil tappet 7 (8) and the suction/exhaust pulp 4 (5) and the oil tappet 7 (8) extends to absorb the gap, the stroke of the oil tappet is of the end-pivot type shown in the conventional example. The length is approximately 1/2 compared to that of . In this way, the oil tappet 9 (
Oil tappet 9 (10) can reduce the operating stroke of 10) compared to conventional ones.
The operation of the internal combustion engine can be stabilized and its durability improved, and the overall internal combustion engine can be made more compact.

In addition, in the above-mentioned valve train mechanism, the boot 25 is disposed within the chamber 32 and is separated from the chamber in which other parts in the cylinder head l are disposed, so that the camshaft 6 and the rocker arm This prevents a problem in which oil droplets for lubricating the boots 25 and the like hit the boot 25 and enter the inside through the side wall of the boot 25.

Furthermore, in the above-mentioned valve mechanism, a part of the oil splashes floating in the cylinder head l is received by the oil reservoir 14, and the oil received here is passed through the hole 15 to the block 11.
Since the oil groove 16i is guided and the relative movement of the oil tappet 9 (10) with respect to the block 11 is made smooth, the function of the oil tappet 9 (10) is not impaired. Further, the block 11 not only functions as a partition wall that partitions the oil tappet boot 25 from the lower high pressure chamber 23 side, but also functions to prevent the oil tappet 9 (10) from falling down.

FIG. 4 shows another embodiment of the invention. In this example, block 1! Box 4 with the top open on the side! is installed and used as an oil reservoir. This oil reservoir communicates with the oil groove 16 via a hole 42 penetrating the block 11.

FIG. 5 shows yet another embodiment of the invention. In this embodiment, oil is directly supplied to the groove 16 from the oil pump P through the oil passage 43 and the hole 42 penetrating the block 11 without providing an oil reservoir.

"Effects of the Invention" As explained above, the present invention provides the following excellent effects.

Since the oil tappet is placed at the upper center of the rocker arm in the lengthwise direction, the operating stroke of the oil tappet is approximately 1/2 that of a conventional end-pivot type, resulting in more stable operation and increased durability. You can improve your sexual performance. In addition, the oil tappet is placed at the upper center in the length direction of the rocker arm, and the boot is placed above the oil tappet, so the boot is shifted to the side from directly above the combustion chamber, which is the hottest area. Since the boot is located away from the combustion chamber, the effect of heat on the boot can be reduced. In addition, the amount of oil splashed on the boots can be reduced, and oil does not enter from the side walls of the boots.

Further, an oil groove is provided on the sliding surface of the partition wall with the oil tappet, and oil is constantly supplied to this oil groove, so that the operation of the oil tappet is not hindered by the partition wall.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of the upper part of the internal combustion engine, FIG. 2 is a partially enlarged sectional view of the upper part of the internal combustion engine, and FIG. FIG. 4 is a sectional view of a main part showing another embodiment of the present invention, and FIG. 5 is a sectional view of a main part showing still another embodiment of the invention. ! ... Cylinder head, 4 ... Intake valve, 5 ... Exhaust valve, 6 ... Camshaft, 7.8 ... Rocker arm, 9.10
... Oil tappet, 11 ... Block (bulkhead), 13 ... Holding plate, 14 ...
...Oil reservoir, 15.42 ...hole, 16...
... Oil groove, 23 ... High pressure chamber, 25 ...
...Boots, 26...Reservoir room. 41・
...Box, P...Oil pump, 43...
...Oil passage. Figure 2 Figure 4 12 Figure 5 Screen

Claims (1)

[Claims] In a valve operating mechanism in which a camshaft is provided at the upper part of the cylinder head, and a rocker arm is driven by the camshaft to open and close an intake valve or an exhaust valve, the rocker arm is sealed at the upper center in the longitudinal direction. The camshaft is supported on the cylinder head main body side via an oil tappet, and the camshaft is arranged at the lower part of one end, and the intake valve or the exhaust valve is arranged at the lower part of the other end. A high pressure chamber is defined on the side thereof, and a reservoir chamber surrounded by an elastic boot is formed on the side of the cylinder head main body support portion, and furthermore, the reservoir chamber is formed on the outer periphery of the oil tappet and extends from the cylinder head main body side and is surrounded by the boot. The internal combustion engine is characterized in that a partition wall is provided to partition the space from the high pressure chamber side, an annular oil groove is provided on the sliding surface of the partition wall against the oil tappet, and an oil supply means is connected to the oil groove. Engine valve mechanism.