JPS62233410A - Tappet valve mechanism in internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce pressure produced at a sliding portion, by fixing the body of a rush adjuster to a tappet holder and causing a plunger to slidably support locker arms for providing a long sliding portion over the entire length of the body. CONSTITUTION:When intake and exhaust valves 4, 5 are opened and closed through locker arms 7, 8 in accordance with the rotation of a cam shaft 6, the locker arms 7, 8 are slidably supported by a hydraulic rush adjuster 30. The hydraulic rush adjuster 30 comprises a cylindrical body 18 with a bottom, a plunger 20 inserted into the body 18 for forming a high pressure chamber 19 therein and a rubber boot 22 for forming a reservoir chamber 21 between the opening of the body 18 and the projection of the plunger 20. The body 18 is fixed to a tappet holder 29 and the projection of the plunger 20 is held is abutment against the center of the locker arms 7, 8 for supporting the locker arms 7, 8 slidably.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a valve mechanism in an internal combustion engine, and in particular,
The present invention relates to a valve mechanism in which a sealed hydraulic lash adjuster is provided in a power transmission system between a valve body and a camshaft to automatically eliminate gaps that occur in the dynamic horn transmission system.

``Prior Art'' In general, a valve train (1) in an internal combustion engine has a camshaft that is driven to rotate in response to the rotation of the internal combustion engine, and a valve body that is opened by being oscillated by the camshaft. It is equipped with a rocker arm that presses and moves in the direction.

In the valve train having such a configuration, in order to prevent the sealing effect from decreasing due to thermal expansion of the valve body, thermal expansion of the valve body is provided between the valve body and the rocker arm.
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* e-p < It, a clearance is provided, but as this valve clearance expands due to wear etc., impact noise is generated between the rocker arm and the valve body when the valve mechanism operates. This has the problem of causing

Therefore, conventionally, a hydraulic lash adjuster is provided at the center of the swing of the rocker arm to apply a pressing force to the rocker arm to the extent that the sealing effect of the valve body in the closed position is not reduced. The above-mentioned valve clearance is maintained at zero by constant pressure towards the valve body, and the above-mentioned hydraulic lash adjuster has a sealed structure that does not require the supply of hydraulic oil. As a specific example, the present inventors have proposed a valve train having the structure shown in FIG.

This valve mechanism is installed in a space formed by a cylinder head 2 of an internal combustion engine 1 and a head cover 3 attached to the cylinder head 2, and is located approximately in the center of the cylinder head 2 with an intake valve 1. A camshaft 6 rotatably disposed between the exhaust valve 5 and rotationally driven by the crankshaft (path shown) of the internal combustion engine l, and between the camshaft 6 and the intake valve 4 and exhaust valve 5 described in 1iii. rocker arms 7 and 8 provided on each of the rocker arms 7 and 8, and a hydraulic lash adjuster 9 and IO that swingably support substantially central portions of the rocker arms 7 and 8 in the longitudinal direction;
a tappet holder 11 fixed to the cylinder head 2 and to which the heavy pressure lash adjusters 9 and 10 are attached;
It is equipped with The tappet holder 11 is composed of a holder base 12 made of aluminum alloy and fixed to the cylinder head 2, and a retainer 13 bolted to the holder base 12. The holder base 12 has each rocker arm 7,
Guide holes 14 and I5, which are perpendicular to the holding plate 13, are formed at positions facing the central part of the holder base L2 by press-fitting bushings 14a and 15a made of steel into the holder base L2, and the guide holes Sealed chambers 16 and 17 are formed between 14 and 15 and the retainer 13 to which engine lubricating oil is supplied.

On the other hand, each of the hydraulic lash adjusters 9 and 1O is a so-called closed type hydraulic lash adjuster in which hydraulic oil is sealed in the lash adjuster, and has a bottomed cylindrical body 18 (
18a-18b) and the body l8 (18a/18b)
The body 18 (18a, 1
High pressure chamber 19 (19a) in which hydraulic oil is confined
・When 19b) is formed, body 1g (18a) is formed.
- The plunger 20 (20a, 20b) protrudes outside from the opening of the body 18 (18b), and the body 18 (18a).
-18b) and the outer periphery of the opening of the plunger 20 (20a).
・Rubber boots 22 (20b) that form reservoir chambers 21 (21a, 21b) that are provided between the outer periphery of the protruding end of the 22a, 22b), plunger springs 23 (23a, 23b) disposed in the bulky high pressure chambers 1919a to 19b) and springing in the direction of protruding the blunt gloss 20 (20a, 20b), and the high pressure chambers. 19 (19a, 19b) from flowing backward toward the reservoir chamber 21 (21a, 21b), and is slidably fitted into the body 18 (21a, 21b). At the same time, the protruding ends of the plungers 20 (20a, 20b) are held down by the plate 1.
3, and then press the On body 1g (18a/1
The bottom part of the rocker arm 8b) is attached to the rocking center of the rocker arms 7 and 8 by means of a slider so that the rocker arm can swing freely.

As the camshaft 6 rotates, the rocker arms 7 and 8 are swung, so that both the valves 4 and 5 are rotated.
Opening/closing operations are difficult.

In addition, in the case where there is no gap between the rocker arms 7 and 8 and the camshaft 6 and both valves 4 and 5, the plungers 20 (20a and 2
0b) as the fixed side, plunger spring 23 (2
The body 18 (18a, 23b) is
18b) is slid to protrude from the tappet boulder It, thereby pressing the rocker arms 7 and 8 toward both the valves 4 and 5 and the camshaft 6, thereby eliminating the above-mentioned gap. Furthermore, the body 18 (18a
-18b) and the plunger 20 (20a, 20b), the hydraulic fluid in the reservoir chamber is '3RI'.
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By preventing backflow, the body 18 (18a,
18b) and the plungers 20 (20a, 20b) are maintained, and the gap is removed.

"Problems to be Solved by the Invention" The present invention aims to improve the following problems that remain in the above-mentioned proposal by the present inventors.

In other words, in the valve train having the above-mentioned configuration, when the valve body is opened and closed, a load is applied to the hydraulic lash adjusters 9 and 10 via the rocker arms 7 and 8, and the negative component of the load is applied to the hydraulic lash adjusters 9 and 10. Since it acts perpendicularly to the sliding portion of the adjuster 9/10 and the tappet holder 11, the side pressure load and the moment generated thereby must be supported by the sliding portion of the tappet holder 11. In other words, the body 18 is slid while being pressed against one of the inner surfaces of the guide holes 14 and 15. However, as mentioned above, the closed type hydraulic lash adjuster 9/1O is used, and the rocker arm 7
・When the hydraulic pressure adjuster 8 is supported at its center, the length of the sliding portion between the bending hydraulic adjusters 9 and IO and the tappet holder 11 is regulated by the rubber boots 22 and the rocker arms 7 and 8. The problem is that the degree of freedom in stress design is limited. Further, in order to ensure smooth sliding movement of the body I8, the body 18 (18a-
18b) and the tappet holder 11, but in order to do this, a lubricating oil supply device such as engine oil is required, which tends to complicate the structure.

The present invention aims to provide a valve mechanism for an internal combustion engine that can effectively solve several problems in the above-mentioned proposal of the present inventors. In particular, the valve mechanism includes a hydraulic lash adjuster that swingably supports the rocker arm.
A cylindrical body with a bottom, a high-pressure chamber that is slidably fitted into the body and in which hydraulic oil is confined, and a high-pressure chamber that protrudes outside from an opening of the body. A rubber boot is provided between the opening of the body and the protrusion of the plunger and forms a reservoir chamber for storing hydraulic oil to be supplied to the high pressure chamber. One of the plungers is fixed to a tappet holder provided near the rocker arm, and the other plunger is swingably connected to the center of swing of the rocker arm.

"Function" The valve mechanism according to the present invention has the body of the hydraulic lash adjuster fixed to the tappet boulder and the rocker arm supported by the plunger so as to be able to swing, thereby absorbing a load perpendicular to the axis of the hydraulic lash adjuster. The sliding part between the body and the plunger is supported to maximize the length of the sliding part that supports the load, and the sliding part between the hydraulic lash adjuster and other components is expanded as much as possible. This eliminates the need for lubrication.

An embodiment of the present invention will be described below with reference to FIG.

In the following description, parts common to those in FIG. 1 are designated by the same reference numerals to simplify the description.

FIG. 2 is a longitudinal cross-sectional view of the head of an internal combustion engine to which the valve mechanism according to the present embodiment is applied.
It is equipped with

An intake valve 4, an exhaust valve 5, and a camshaft 6 are attached to the cylinder head 2, and the intake valve 4
and the respective valve stems 4a and 5 of the exhaust valve 5.
a, the retainer 26 (26a, 26b) is connected to the cock 27
(27a, 27b), and between the retainer 26 (26a, 26b) and the cylinder head 2, the intake valve 4 and the exhaust valve 5
Valve spring 2g (28a
・28b) is interposed.

Opening/closing operation of the intake valve 4 and the exhaust valve 5 installed in this way The valve mechanism of this embodiment is provided with the camshaft 6 and between the camshaft 6 and both valves 4 and 5. The rocker arms 7 and 8, the camshaft 6 of the rocker arms 7 and 8, and both valves 4 and
A tappet holder 29 is provided on the cylinder head 2 at a distance on the opposite side from the tappet holder 29, and a hydraulic lash adjuster 30 is fixed to the tappet holder 29 by press-fitting or the like to swingably support the rocker arms 7 and 8. 30a・30
b), the hydraulic run-your-adjuster 30 (30a
・30b) is a bottomed cylindrical body 18 as in FIG.
(18a, 18b) and the body l8 (18a, 18b)
) a plunger 20 (20a, 20b) that forms a high pressure chamber 19 (19a, 19b) in the body 18 (18a-18b) and protrudes to the outside from an opening of the body 18 (18a-18b);
Rubber boots 22 (22a, 22b) provided between the opening of the body 18 (18a, 18b) and the protrusion of the plunger 20 (20a, 20b) and forming a reservoir chamber 21 (21a, 21b); The body 18 (18a, 18b) is fixed to the tappet holder 29, and the plunger 20 (20a, 20b) is fixed to the tappet holder 29.
) has a schematic structure in which the protruding end portions of the rocker arms 7 and 8 are swingably connected to the swing centers of the rocker arms 7 and 8.

Next, to explain these details, the tappet boulder 29 has rT bottom-shaped mounting holes 3I and 32 that open downward, that is, toward the rocker arms 7 and 8. Adjust the handles r11 of both valves 4 and 5 to approximately 2
The hydraulic lash adjusters 30UOa and 30b) are formed so as to be parallel to the dividing line, and the camshaft 6 (if) is inserted above.
The four parts 33 in which the engine oil splashed up by the above-mentioned holes 31 and 32 are stored are formed in correspondence with the holes 31 and 32, and the through-hole 34 guides the engine oil in the recess 33 downward to the tappet holder 29. However, the attachments are formed parallel to the holes 3I and 32.

The hydraulic lash adjuster 30 (30a, 30b) has its body 18 (18a-18b) inserted into the mounting hole 31-32, and the mounting hole 31-32.
2 so that the rubber boots 22 (22a, 22b) are exposed below the tappet holder 29, and each plunger 20 (20a, 22b) is
0b) is fixed to the tappet holder 29 in a state where the protruding end thereof is positioned at the center of the rocker arms 7 and 8. The protruding ends of the plungers 20 (20a, 20b) are formed in a spherical shell shape, and are fitted into the rocker arms 7, 8 to support the rocker arms 7, 8 in a swingable manner. It is supposed to be done. Furthermore, in this embodiment, the plunger 20 (20a, 20b) and the rubber boot 22 (22a
・Fixing metal fittings 35 (35a, 35
b) covers the rubber boots 22 (22a, 22b),
In addition, the oil reservoir 36 (36a, 36b) is extended to open toward the tappet holder 29, and the oil reservoir 36 (36a, 36b) is opened to the tappet holder 29. By stopping the engine oil falling from the through hole 34 and covering the rubber boots 22 (22a, 22b) with the engine oil, contact between the rubber boots 22 (22a, 22b) and air is cut off. It has become.

Thus, the valve train of this embodiment configured as described above applies and releases a pressing force to the camshaft upon starting of the internal combustion engine 25, and applies and releases the pressing force to the camshaft when the internal combustion engine 25 is started.
The intake valve 4 is swung around the connecting portion with the hydraulic lash adjuster 30 (30a, 30b).
and opens and closes the exhaust valve 5.

In the case where there is no gap between the rocker arms 7 and 8 and the camshaft 6 and both valves 4 and 5, the body 18 (18a-18b) and the plunger 20 (2
0a and 20b), the above-mentioned gap is removed.

In other words, if the gap mentioned above does not occur, the plant gears 20 (20a, 20b
) is released, and the load acting on the body 18 (
18a, 18b) is moved in the longitudinal direction by tappet boulder 2.
9, the body 18 (1
8a-18b) as a support, the plunger 2 is moved by the elastic force of the plunger spring 23 (23a, 23b).
゜(20a ・20b) is the body [8(18a-18b
), and the rocker arms 7 and 8
By doing so, the log car arms 7 and 8, the camshaft 6, and the valves 4 and 5 are connected. are kept in contact with each other at all times.

During such a gap removing action, the movement of the hydraulic fluid inside the hydraulic lash unjustifiers 30 (30a, 30b) and its action are similar to those in the conventional closed type hydraulic lash adjusters 9, 10.

On the other hand, when opening and closing both valves 4 and 5, each hydraulic lash adjuster 3 (1 (30
External force acts on the sliding parts of the hydraulic lash annoyaster 30 (30a, 30b), but the sliding parts of the hydraulic lash annoyaster 30 (30a, 30b) are connected to the body 1g (18a, 18b) and the plunger 2.
0 (20a, 20b), and
Since the sliding portion is formed over almost the entire length of the body 18 (18a, 18b) and is kept long, the hydraulic pressure generated by the outer horn can be suppressed to a small level. Moreover, the open end of the body 1g (18a, 18b) is connected to the rubber boot 22 (22a, 22b) and the plunger 2.
Even if it extends to the connecting part with 0 (20a, 20b), interference with other components can be avoided, so the length of the sliding part mentioned above is set even larger, and the drop in oil pressure mentioned above is avoided. be promoted. Further, the external force is transmitted through the fitting portion between the body 1g (18a and 18b) and the tappet holder 29, but since both are fixed to each other, sufficient strength against the external force must be ensured. . Therefore, the degree of freedom in stress design is greatly improved. There is no need to lubricate between the hydraulic lash adjuster 30 (30a, 30b) and the tappet bolter 29, and
Lubrication between the sliding parts of the body 18 (18a, 18b) and the plungers 20C (20a, 20b) is performed by the hydraulic oil sealed in the hydraulic lash adjuster 30 (30a, 30b), so new lubrication is required. There is no need to provide an oil supply means, and the structure of the valve mechanism is simplified.

Further, in this embodiment, during operation of the internal combustion engine 25, engine oil is splashed up by the camshaft 6 etc. in the space formed by the cylinder head 2 and the head cover 3, and then as the engine oil falls, the It is stored in the recess 33 of the tappet holder 29. and,
The engine oil in the recess 33 is transferred to the tappet holder 29.
The oil reservoir 36 (36 a・The rubber boot 22 (22a) is filled with engine oil.
- 22b) and the outside air are cut off.

Therefore, the outside air
) is prevented from penetrating into the reservoir chamber 21 (21a, 21b), and each hydraulic lash adjuster 3
The reliability of the operation of ゜(30a, 30b) is increased.

On the other hand, FIG. 3 shows another embodiment of the present invention.

In this embodiment, the body 18 (18a-18b) is press-fitted into the tappet holder 29 when fixing the hydraulic adjuster 30 (30a, 30b) to the tappet holder 29 in the previously described embodiment. Instead, the brackets 20 (20a, 20b) are fixed to the tappet bolter 29 in the correct size, and the rocker arms 7, 8 are supported by the body 18 (18a, 18b) at an angle of 1° so as to be movable.

With such a configuration, the following effects can be obtained in addition to the effects of the embodiment described above.

■Rocker arms 7 and 8 and hydraulic lash adjuster 30
(30a, 30b), body 1 with a large outer diameter
By doing this on the 8 (18a, 18b) side, the radius of the spherical surface of the fitting portion can be increased, and the pressure receiving area can also be expanded, thereby improving wear resistance.

■The bending moment acting on the hydraulic lash adjuster 30 (30a, 30b) is reduced by 1g of the body with a large section modulus (
18a-18b) to reduce stress.

(2) By fixing the plunger 20 (20a, 20b) side, which has a smaller outer diameter, to the tappet holder 29, the tappet holder 29 can be made smaller.

Note that the shapes and dimensions of the constituent members shown in each of the above embodiments are merely examples, and can be variously changed based on the type of internal combustion engine to which the invention is applied.

"Effects of the Invention" As described above, the valve mechanism in the internal combustion engine according to the present invention includes a camshaft that is rotatably driven in response to the rotation of the crankshaft of the internal combustion engine, and a camshaft that is oscillated by the camshaft. The hydraulic run-your-adjuster is fixed to a tappet holder provided near the rocker arm and supports the rocker arm in a swingable manner. The Rano Your Adjuster has a cylindrical body with a bottom, and is slidably fitted into the body to form a high-pressure chamber in which hydraulic oil is confined, and protrudes to the outside from an opening in the body. a rubber boot that is provided between the opening of the body and the protrusion of the plunger and forms a reservoir chamber for storing hydraulic oil to be supplied to the high pressure chamber; Either the body or the plunger is fixed to the tappet holder, and the other is swingably connected to the swing center of the rocker arm, which provides the following excellent effects. .

■The sliding part of the hydraulic lash adjuster is concentrated between the body and the plunger, and the sliding part is kept long over almost the entire length of the body.
By suppressing the blood pressure generated in the sliding part of the hydraulic run-your-own system due to external force applied from the arm, and by fixing the body or plunger and tappet holder to each other, the strength against the external force is sufficiently increased. This can greatly improve the degree of freedom in stress design.

■It eliminates the need for lubrication between the hydraulic lash adjuster and the tappet holder, and lubricates between the body and the plunger using the hydraulic oil sealed in the hydraulic lash adjuster, creating a new lubricant l111+ supply means. This makes it possible to simplify the construction of the valve mechanism.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an internal combustion engine equipped with a valve mechanism according to a previous proposal by the present inventors, FIG. 2 is a view similar to FIG. 1 showing an embodiment of the present invention, and FIG. The figure is similar to FIG. 1 showing another embodiment of the present invention; 2... cylinder head; 3...
・Head cover, 4..Intake valve, 4a..Valve stem, 5..Exhaust valve, 5a..Valve stem.
6...Camshaft, 7.8...Rocker arm, 1
8 (18a-18b)--Body, 19 (19a-19b)--High pressure chamber, 20 (20a-
20b)...Plunger, 21(21a ・21b)-
...=-Reservoir chamber, 22 (22a, 22b)...Rubber boots, 23 (23a, 23b)...Plantsya spring, 24 (24a, 24b)...Deck valve, 25
... Internal combustion engine, 29 ... Tappet holder, 30 (
30a・30b) Hydraulic lash anoyasuta, 31・
32... Mounting hole, 34... Through hole, 35 (35a
・35b)・Fixing bracket, 36(36a・36b)・
・Oil reservoir.

Claims (1)

[Claims] A camshaft that is rotationally driven in response to the rotation of a crankshaft of an internal combustion engine, a rocker arm that presses and moves a valve body by being swung by the camshaft, and a tappet provided near the rocker arm. A hydraulic lash adjuster is fixed to the holder and swingably supports the rocker arm. A plunger is provided between the opening of the body and the protrusion of the plunger, and a plunger is provided between the opening of the body and the protrusion of the plunger to form a high pressure chamber in which hydraulic oil is confined, and the plunger is protruded to the outside from an opening of the body. and a rubber boot forming a reservoir chamber for storing supplied hydraulic oil, and either the body or the plunger is fixed to the tappet holder, and the other swings around the swing center of the rocker arm. A valve mechanism for an internal combustion engine characterized by being freely connected.