JPH0561401U - Valve mechanism of internal combustion engine - Google Patents

Abstract

(57) [Summary] [Objective] Optimum combustion according to the purpose due to the inclined arrangement of the plurality of valve stems 8a by bringing the valve lifter 14 equipped with the hydraulic lash adjuster 21 into contact with the upper end of the valve stem 8a. While realizing the shape, the sliding friction between the valve lifter 14 and the upper end of the valve stem 8a is effectively reduced. [Structure] Between a plurality of valve stem 8a upper ends (upper surface of valve upper seat 19) inclined and arranged with respect to a plane X orthogonal to an axis m of an intake camshaft 10 and a lower surface of a plunger 25 of a hydraulic lash adjuster 21. The ball member 31 is interposed. Then, by the ball member 31,
The behavior of the valve lifter 14 in the direction orthogonal to the axis m of the intake camshaft 10 due to the contact with the cam surfaces 18a and 18b of the intake camshaft 10 will be described.
The opening / closing drive of the intake valve 8 in the direction is converted to bring the upper end of the valve stem 8a and the lower surface of the plunger 25 into one point contact.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve operating mechanism of an internal combustion engine, and more particularly, to improvement of a valve operating mechanism provided with a hydraulic lash adjuster.

[0002]

[Prior Art]

 Conventionally, as a valve mechanism of an internal combustion engine, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-125708, a valve stem is arranged so as to be inclined with respect to a plane orthogonal to the axis of a camshaft. A valve lifter that behaves in a direction orthogonal to the axis of the cam shaft by contacting the cam surface of the cam shaft is provided between the end portion of the valve stem and the cam shaft, and between the end portion of the valve stem and the valve lifter. A hemispherical spherical contact portion is formed between them, and the spherical surface contact between the convex spherical surface portion at the end of the valve stem and the concave spherical surface portion of the valve lifter causes the behavior of the valve lifter to move toward the valve stem. It is known that the behavior of the valve, that is, the one that is converted into the opening and closing drive.

[0003]

[Problems to be solved by the device]

 By the way, in an engine having a plurality of valves per cylinder, which is excellent in combustion efficiency as a recent tendency, it is appropriate to incline the plurality of valve stems with respect to the plane orthogonal to the axis of the camshaft as described above. It is strongly desired to realize the optimum combustion mode according to the purpose by effectively arranging the spark plugs, etc. while arranging in order to achieve smooth swirl formation.

However, in the case of the above-mentioned conventional one, mutual contact for converting the behavior of the valve lifter into the opening / closing drive of the valve toward the valve stem is caused by the convex spherical surface portion of the valve stem end and the concave spherical surface portion of the valve lifter. Due to the spherical contact of the valve lifter, the resistance of the convex spherical part at the end of the valve stem that slides against the concave spherical part of the valve lifter becomes large, and the sliding friction between both spherical contact parts increases. Will have. Therefore, it has been impossible to reduce the sliding friction between the valve lifter and the end of the valve stem while realizing the optimal combustion mode according to the purpose by the above-mentioned tilted arrangement of a plurality of valve stems.

The present invention has been made in view of the above points, and its object is to focus on a hydraulic lash adjuster provided in a valve train of an internal combustion engine for automatically adjusting the valve clearance thereof. By minimizing the mutual contact between the valve lifter equipped with the lash adjuster and the end of the valve system, the valve lifter and valve can be realized while realizing the optimal combustion mode by the tilted arrangement of multiple valve stems. It is intended to effectively reduce the sliding friction with the end of the stem.

Further, it is also an object of the present invention to improve the durability of the camshaft by relaxing the local stress concentration in the bending direction of the camshaft by the inclined arrangement of the plurality of valve stems.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the solution means devised by the invention of claim 1 is premised on a valve operating mechanism of an internal combustion engine in which a valve system is arranged to be inclined with respect to a plane orthogonal to the axis of a camshaft. .. Further, a hydraulic lash adjuster that behaves in a direction orthogonal to the axis of the cam shaft by contacting the cam surface of the cam shaft is provided between the end portion of the valve stem and the cam shaft, and the valve stem is also provided. Between the end of the valve and the hydraulic lash adjuster, a ball member that converts the behavior of the hydraulic lash adjuster into the opening / closing drive (behavior) of the valve in the valve stem direction is rotatably supported, and the valve stem The ball member is configured to contact the end of the hydraulic lash adjuster.

Further, the solution means devised by the invention according to claim 2 is such that the ball member according to claim 1 is limited and is lubricated by the oil supplied to the hydraulic lash adjuster. is there.

[0009]

[Action]

 With the above structure, according to the first aspect of the invention, when a plurality of valve stems are arranged in a tilted manner in an engine having a plurality of valves per cylinder, which is excellent in combustion efficiency, which tends to be a recent trend, a smooth swirl is provided. In addition to achieving the optimum combustion pattern by forming the spark plugs effectively by arranging the spark plugs effectively, the distance between the cams in the thrust direction of the camshaft is expanded, and the cam shuffle is pushed up from the valve stem. The stress in the bending direction is distributed in the thrust direction, and the stress concentration on the camshaft is relieved.

In that case, since the contact between the hydraulic lash adjuster (valve lifter) and the end portion of the valve stem is the contact of the ball member rotatably supported between the two, it slides with respect to the valve lifter. The resulting resistance of the valve stem end is small, and the sliding friction between the contact parts is effectively reduced.

Further, according to the second aspect of the invention, since the ball member is lubricated by the oil of the hydraulic lash adjuster, the wear of the ball member is suppressed, and the gap between the valve lifter and the valve stem end is suppressed. The sliding friction is reduced more effectively.

[0012]

[Effect of the device]

 As described above, according to the valve operating mechanism of the internal combustion engine in the first aspect of the invention, the ball stem member rotatably supported between the valve stem end portion and the hydraulic lash adjuster brings them into contact with each other. Therefore, while achieving optimal combustion according to the purpose by arranging multiple valve stems in an inclined arrangement, stress distribution in the camshaft bending direction improves the durability of the camshaft, while at the same time increasing the valve lifter and valve stem end. Sliding friction between the parts can be effectively reduced.

According to the valve operating mechanism of the internal combustion engine in the invention of claim 2, the ball member is lubricated by the oil of the hydraulic lash adjuster to improve the wear resistance of the ball member. The sliding friction between the valve lifter and the end of the valve stem can be reduced more effectively.

[0014]

【Example】

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

FIG. 1 shows a direct drive type valve mechanism according to a first embodiment of the present invention applied to a cylinder head of a four-valve engine as an internal combustion engine. In the figure, 1 is a cylinder block in which a cylinder (bore) 2 is formed, 3 is a cylinder head joined to the cylinder block 1 via a gasket 4, and combustion is performed between the cylinder 2 and the lower surface of the cylinder head 3. A chamber 5 is formed. The cylinder head 3 is formed with two intake ports 6 and 6 that open into the combustion chamber 5 and two exhaust ports (not shown) that open into the combustion chamber 5. The intake valves 8 and 8 that open and close the openings of the intake ports 6 to the combustion chambers 5 and the exhaust valves that open and close the openings to the openings of the exhaust ports 6 to the combustion chambers 5, respectively. Each is provided with a tab (not shown).

On the cylinder head 3, both lateral ends (left and right lateral ends in the figure) of the cylinder head 3 extend in the cylinder row direction, and are rotationally driven by a crankshaft (not shown). An intake camshaft 10 and an exhaust camshaft (not shown) are provided. The intake camshaft 10 is rotatably supported by a semicircular bearing portion 3a provided on the cylinder head 3 and a cam cap 11 attached to the cylinder head 3 so as to cover the intake camshaft 10. Further, a cylinder head cover (not shown) is capped on the cam cap 11. On the intake camshaft 10, cams 12a, 12b corresponding to the intake valves 8 are formed, respectively. The valve stems 8a of the intake valves 8 are inclined so that their upper ends are away from each other with respect to the plane X orthogonal to the axis m of the intake camshaft 10, that is, the valve stems 8a are opposed to the plane X. They are arranged in a tilted direction (left and right in the figure) and orthogonal (direction shown in the figure).

Further, on the upper part of the cylinder head 3 (only the intake side is shown in the figure), there is interposed between the cams 12 a and 12 b of the intake camshaft 10 and the upper end of the valve stem 8 a of each intake valve 8. The valve lifters 14, 14 are provided, the cam surfaces 18a, 18b of the cams 12a, 12b contact the upper surfaces of the valve lifters 14, and the hydraulic lash adjuster 21 (provided inside the valve lifters 14 ( By direct contact with the upper end of the valve stem 8a of each intake valve 8 via (described later), a direct drive valve operating mechanism 13 on the intake side for controlling the opening / closing of each intake valve 8 is configured. The exhaust side valve operating mechanism (not shown) for controlling the opening / closing of the exhaust valve has the same structure as the intake side direct drive type valve operating mechanism 13, and therefore its explanation is omitted.

Each intake valve 8 which is driven to open and close by the valve operating mechanism 13 is slidably supported by the cylinder head 3 via a valve guide 15 and has a cross-section approximately T that is crowned with the upper end of the valve stem 8a. A valve spring 16 that is compressed between the character-shaped valve upper seat 19 and the cylinder head 3 is constantly biased in the valve closing direction. The valve upper seat 19 is integrally fixed to an inner valve upper seat 19a located inside and an outer valve upper seat 19b located outside. Further, in the cylinder head 3 below the intake camshaft 10, circular valve-shaped valve lifter sliding parts 17, 17 are formed close to each other in the intake camshaft 10 direction (vertical direction in the figure). The valve lifters 14 and 14 are inserted into the valve lifter sliding parts 17 so as to be slidable. A hydraulic lash adjuster 21 for transmitting the load from the cams 12 a and 12 b of the intake camshaft 10 to each intake valve 8 is provided inside each valve lifter 14, and the lash adjuster 21 is provided. Comes into contact with the cam surfaces 18a, 18b of the cams 12a, 12b of the intake camshaft 10 via the valve lifter 14 to move in the vertical direction orthogonal to the axis m of the intake camshaft 10. .. Further, a reserve chamber 22 is formed inside each valve lifter 14 corresponding to the outer peripheral side of the lash adjuster 21, and the reserve chamber 22 is provided with an oil passage (not shown) formed in each valve lifter 14. Is supplied to the lash adjuster 21 (hydraulic chamber 26 described later).

The hydraulic lash adjuster 21 has a bottomed cylindrical adjuster body 24 fitted into a fitting recess 23 formed in each valve lifter 14, and a liquid on the outer peripheral surface of the adjuster body 24. And a plunger 25 that is fitted in a slidable state so as to be slidable in the vertical direction. A hydraulic chamber 26 is defined by the adjuster body 24 and the plunger 25, and the hydraulic chamber 26 is formed in the adjuster body 24. It communicates with the reserve chamber 22 through a communication hole 27 which is opened. In addition, a plunger spring 28 is provided between the adjuster body 24 and the plunger 25 so as to urge the plunger 25 downward (toward the intake valve 8 side), and the hydraulic pressure is also increased. A check valve 30 including a check valve ball 29 that opens and closes the communication hole 27 and a check valve spring (not shown) that biases the check valve ball 29 in the valve closing direction is disposed in the chamber 26. ing. Therefore, when a gap is created between the valve lifter 14 and the cam surfaces 18a, 18b of the cams 12a, 12b of the intake camshaft 10, the plunger 25 moves toward the intake valve 8 due to the urging force of the plunger spring 28. The check valve 30 opens due to the pressure drop in the hydraulic chamber 26 due to this, and the oil in the reserve chamber 22 flows into the hydraulic chamber 26 through the communication hole 27, whereby the lash adjuster 21 fills the gap. As described above, the check valve 30 is closed due to the increase in the pressure in the hydraulic chamber 26 so that the oil flow into the hydraulic chamber 26 is stopped. The oil that has flowed into the hydraulic chamber 26 does not flow back to the reserve chamber 22 due to the sealing action of the check valve 30 even if a load is applied to the lash adjuster 21 from above and below. While being confined, it becomes a rigid body, so that the load from the intake camshaft 10 is reliably transmitted to the intake valve 8.

A feature of the present invention is that the space between the upper surface of the valve upper seat 19 at the upper end of the valve stem 8a of each intake valve 8 and the lower surface of the plunger 25 of the hydraulic lash adjuster 21 extends in the vertical direction. A ball member 31 is provided to convert the behavior of the lash adjuster 21 which behaves into the behavior of the intake valve 8 in the direction of the valve stem 8a inclined by the three-dimensional arrangement, that is, opening / closing drive. The ball member 31 is rotated by a rotation support member 32 at the upper end of the inner valve upper seat 19a, which is formed by projecting the peripheral wall portion of the inner valve upper seat 19a of the valve upper seat 19 of each intake valve 8 upward. It is supported freely. The upper end of the ball member 31 is exposed above the rotation support member 32 (upper end of the valve stem 8a), and the exposed portion (upper end) of the ball member 31 causes each valve stem 8a to be exposed. The upper end comes into point contact with the lower surface of the plunger 25 of the hydraulic lash adjuster 21.

Therefore, in the above-described first embodiment, the valve stem 8a of each intake / exhaust valve 8 is attached to the cylinder head 3 of the engine having four intake / exhaust valves per cylinder, which are excellent in combustion efficiency, which tends to come in recent years. In the case of the slanted arrangement, the optimum swirl pattern can be realized according to the aim by effectively arranging the spark plug while smoothly forming swirl. In addition, the distance between the cams 12a and 12b in the thrust direction of the intake camshaft 10 is expanded, and the stress in the bending direction of the intake camshaft 10 due to the thrust from each valve stem 8a is dispersed in the thrust direction. Thus, the stress concentration on the intake camshaft 10 is alleviated, and the durability of the intake camshaft 10 is improved.

In this case, the upper end of the valve stem 8a (upper surface of the valve upper seat 19) and the lower surface of the plunger 25 of the hydraulic lash adjuster 21 are brought into contact with each other by the ball member 31 interposed between the two 8a, 25. Since the contact is performed by contact, the resistance of the upper end of the valve stem 8a with respect to the lower surface of the plunger 25 of the hydraulic lash adjuster 21 becomes small, and the sliding friction between the contact portions 25, 8a is effectively reduced. As a result, it is possible to effectively reduce the sliding friction between the valve lifter 14 and the end portion of the valve stem 8a while realizing an optimal combustion mode according to the aim by the inclined arrangement of the plurality of valve stems 8a.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the ball member 31 interposed between the upper end of each valve stem 8a and the lower surface of the plunger 25 of the hydraulic lash adjuster 21 is supported on the lower surface side of the plunger 25 of the hydraulic lash adjuster 21. It was done like this. The same parts as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted.

That is, in this example, a substantially conical bulging portion 41 obtained by bulging the lower surface of the plunger 25 downward is provided in the lower portion of the plunger 25 of the hydraulic lash adjuster 21, and the bulging portion 41 A rotation support portion 42 having a substantially arcuate cross section for rotatably supporting the ball member 31 is provided at the tip. The lower end portion of the ball member 31 is exposed so as to be positioned below the lower surface of the rotation support portion 42, and the exposed portion (lower end portion) of the ball member 31 causes the hydraulic lash adjuster 21 to move. The lower surface of the plunger 25 is in point contact with the upper end of each valve stem 8a.

Further, an oil supply passage 43 is formed at the lower end of the plunger 25 so that the oil in the reserve chamber 22 can be supplied to the rotation support portion 42. Are used for lubricating the ball member 31 with respect to the inside of the rotation support portion 42 and the upper end of the valve stem 8a.

In this case, the ball member 31 is lubricated by the oil in the reserve chamber 22 of the hydraulic lash adjuster 21, so that the wear of the ball member 31 is suppressed and the wear resistance is improved, and the valve lifter is improved. The sliding friction between 14 and the upper end of the valve stem 8a can be reduced more effectively.

In each of the above-described embodiments, the ball stem 31 is used to contact the upper end of the valve stem 8a and the lower surface of the plunger 25 of the hydraulic lash adjuster 21 by a single point contact. The valve stem may be formed in a flat surface so that the upper end of the valve stem and the lower surface of the plunger of the hydraulic lash adjuster contact each other on the flat surface of the ball member.

Further, in each of the above embodiments, the four-valve type valve operating mechanism 13 in which two intake valves 8 and two exhaust valves are provided for each cylinder has been described. It can also be applied to a multi-valve type in which two or more are provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an intake valve operating mechanism taken along an axial direction of a camshaft according to a first embodiment.

FIG. 2 is a view corresponding to FIG. 1 according to a second embodiment.

[Explanation of symbols]

 8a valve stem 10 intake camshaft 13 valve mechanism 18a, 18b cam surface 22 hydraulic lash adjuster 31 ball member m intake camshaft axis X plane

Claims (2)

[Scope of utility model registration request] 1. A valve operating mechanism for an internal combustion engine, wherein a valve stem is arranged so as to be inclined with respect to a plane orthogonal to the axis of the camshaft, and the cam is provided between an end of the valve stem and the camshaft. A hydraulic lash adjuster that behaves in a direction orthogonal to the axis of the cam shaft by contacting the cam surface of the shaft is provided, and the hydraulic lash adjuster is provided between the end of the valve stem and the hydraulic lash adjuster. A ball member that converts the behavior of the hydraulic lash adjuster into the behavior of the valve in the valve stem direction is rotatably supported, and the end portion of the valve stem and the hydraulic lash adjuster are in contact with each other by the ball member. A valve operating mechanism of an internal combustion engine, which is characterized in that: 2. A valve mechanism for an internal combustion engine according to claim 1, wherein the ball member is lubricated by oil supplied to the hydraulic lash adjuster.