JP2007192134A - Cylinder head of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder head of an internal combustion engine which enables an oil circulation through a valve tappet and a tappet guide, while preventing dusts in the oil from getting into the valve train of direct acting type. <P>SOLUTION: A tilt part (70a) tilting downward as it goes outward from the opening (60a) of the tappet guide (60), a groove (70b) recessed downward in the lower end of the tilt part, and an oil reservoir (70) made up of an wall (70c) extending upward from the outside surface of the groove are provided in the cylinder head (2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cylinder head of an internal combustion engine of a so-called direct acting valve system in which a valve is directly driven by a cam.

In general, there is a so-called direct-acting internal combustion engine in which a valve system such as an intake valve or an exhaust valve is driven directly by a cam.
A valve tappet is interposed between the valve and the cam, and a guide hole for accommodating the valve tappet is formed in the cylinder head of the internal combustion engine.
Since the valve tappet is pushed by the cam and slides up and down in the guide hole, it is necessary to circulate oil between the valve tappet and the guide hole in order to reduce friction.

As a configuration for circulating oil between the valve tappet and the guide hole in this way, for example, an oil guide groove oriented in the axial direction is formed in the upper part of the guide hole (tappet support hole), and the valve tappet and the guide hole are formed. (See Patent Document 1).
Japanese Patent Laid-Open No. 06-167208

However, in the technique disclosed in Patent Document 1 described above, when dust such as cutting powder is mixed in the oil accumulated in the oil guide groove, the dust is collected between the valve tappet and the guide hole together with the oil. May intrude and cause biting of dust, which may cause problems such as abnormal wear and seizure.
The present invention has been made to solve such problems, and an object of the present invention is to provide a valve tappet and a tappet guide in a direct acting valve system while preventing dusts in oil from entering. It is to provide a cylinder head of an internal combustion engine that can circulate oil between them.

  In order to achieve the above object, the cylinder head of the internal combustion engine according to claim 1 is a cylinder head of an internal combustion engine having a valve directly driven by a cam, and is interposed between the cam and the valve. A valve tappet that is slidably accommodated in a guide hole formed in the cylinder head, and an inclined surface that inclines downward from the cam side opening of the guide hole toward the lower side of the internal combustion engine. An oil reservoir that can store a predetermined amount of oil, and when the amount of stored oil exceeds the predetermined amount, an oil reservoir that supplies the excess oil between the guide hole and the valve tappet It is characterized by having.

In other words, in a cylinder head of a so-called direct-acting valve-operated internal combustion engine having a valve directly driven by a cam, an inclination that inclines downward from the opening of the guide hole that houses the valve tappet. An oil reservoir portion having a surface and capable of storing a predetermined amount of oil that lubricates between the valve tappet and the guide hole is formed.
The cylinder head of the internal combustion engine according to claim 2 is characterized in that, in claim 1, the oil reservoir portion has a groove portion recessed downward from a lower end portion of the inclined portion.

  In a cylinder head of an internal combustion engine according to a third aspect, in the first or second aspect, the oil reservoir portion is characterized in that the inclined portion is formed at an acute angle with respect to the axial direction of the guide hole.

  According to the cylinder head of the internal combustion engine of the first aspect of the present invention using the above means, the valve is provided in the oil reservoir having an inclined surface that is inclined downward as it goes outward from the opening of the guide hole that accommodates the valve tappet. By storing the oil that lubricates between the tappet and the guide hole, dust in the oil can be precipitated in the oil reservoir, and further, the dust can be collected in the lower portion along the inclined surface.

When the amount of oil stored in the oil reservoir exceeds a predetermined amount, the excess oil is supplied between the valve tappet and the guide hole, so that the oil from which dust has been removed is supplied. It can supply between the said valve tappet and a guide hole.
As a result, in the direct acting valve system, the oil can be circulated favorably between the valve tappet and the guide hole while preventing dust in the oil from entering.

According to the cylinder head of the internal combustion engine of the second aspect, since the groove portion is formed from the lower end portion of the inclined portion, the dust can be collected in the groove portion, and the dust is diffused in the oil. Can be prevented.
According to the cylinder head of the internal combustion engine of the third aspect, since the inclined portion is formed at an acute angle with respect to the axial direction of the guide hole, it is possible to reliably collect dusts in the lower portion by a steep inclination. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown a longitudinal sectional view of a cylinder head of an internal combustion engine according to the present invention, and FIG. 2 is an enlarged view of a main part of FIG.
As shown in FIG. 1, a cylinder head 2 of an engine (internal combustion engine) 1 is formed with a pair of inclined surfaces 4 and 6 formed in a so-called pent roof type on the lower surface.

The inclined surfaces 4, 6 form an upper wall of the combustion chamber 8, and one of the inclined surfaces 4, 6 has an opening portion of the intake port 10 extending toward one side of the cylinder head 2. 10a is formed.
In addition, the cylinder head 2 is provided with an intake valve 20 that communicates and shuts off the intake port 10 and the combustion chamber 8 at the opening 10 a of the intake port 10.

Specifically, the intake valve 20 includes an umbrella portion 20a formed in accordance with the opening shape of the opening portion 10a of the intake port 10, and a rod-like stem portion 20b extending vertically from the center of the umbrella portion 20a. ing.
An intermediate portion of the stem portion 20b is supported by a cylindrical stem guide 22 press-fitted into the cylinder head 2 so as to be slidable up and down. A stem seal 24 is provided at the upper end portion of the stem guide 22 to prevent oil or the like from entering between the stem guide 22 and the stem portion 20b.

Further, a locking portion 20c is formed on the upper portion of the stem portion 20b, and a disk-shaped retainer 28 is connected via a valve cotter 26 locked to the locking portion 20c.
The upper end of the spring 30 is in contact with the lower surface of the peripheral edge of the retainer 28. On the other hand, the lower end portion of the spring 30 is in contact with the cylinder head 2 via the spring seat 32.

In addition, a bottomed cylindrical valve tappet 40 is provided that is in contact with the upper end of the stem portion 20b and covers from the retainer 28 to the upper half portion of the spring 30 and is opened downward.
A shim 42 is provided integrally with the valve tappet 40 on the upper surface of the valve tappet 40, and the upper surface of the shim 42 is in contact with the cam 50. The cam 50 has a cam crest 50a that bulges outward, and is formed integrally with a camshaft 52 that is rotatably supported on the upper portion of the cylinder head 2.

The valve tappet 40 is housed in a tappet guide 60 (guide hole) formed in the cylinder head 2 so as to be slidable in the vertical direction.
An oil reservoir 70 for storing oil is formed in the peripheral portion of the entire circumference of the upper opening 60 a of the tappet guide 60.
More specifically, a flat inclined portion 70 a is formed that is inclined downward at an acute angle with respect to the axial direction of the tappet guide 60 as it goes outward from the upper opening 60 a of the tappet guide 60. Further, a groove portion 70b recessed downward is formed at the lower end of the inclined surface 70a. A planar wall portion 70c extending upward from the outer side surface of the groove portion 70b is formed, and the oil reservoir portion 70 is constituted by the inclined portion 70a, the groove portion 70b, and the wall portion 70c.

  On the other hand, of the inclined surfaces 4 and 6, the other inclined surface 6 is formed with an opening 80 a of an exhaust port 80 extending toward the other side surface of the cylinder head 2. The cylinder head 2 is provided with an exhaust valve 82 that connects and disconnects the exhaust port 80 and the combustion chamber 8 at the opening 80 a of the exhaust port 80. The exhaust valve 82 has the same configuration as the intake valve 20, and the structure of the cylinder head 2 on the side where the exhaust valve 82 is provided is the same as the structure on the side where the intake valve 20 is provided. Therefore, detailed description here is omitted.

The operation of the cylinder head of the internal combustion engine according to the present invention configured as described above will be described below. In the cylinder head 2, the actions on the intake valve 20 side and the exhaust valve side are almost the same, and therefore, the action on the intake valve 20 side will be mainly described here.
While the engine 1 is being driven, rotation of a crankshaft (not shown) is transmitted to the camshaft 52, and the camshaft 52 rotates.

Then, the cam 50 rotates together with the camshaft 52, the valve tappet 40 is pushed down by the cam crest 50a, and the intake valve 20 is pushed down accordingly. As a result, the intake port 10 and the combustion chamber 8 communicate with each other.
When the camshaft 52 further rotates and the cam crest 50a passes the upper surface of the valve tappet 40, the intake valve 20 is returned to the opening 10a of the intake port 10 by the urging force of the spring 30, and the intake port 10 and the combustion chamber 8 are separated from each other. Blocked.

Further, an oil pump (not shown) is operated by rotation of the crankshaft while the engine 1 is driven, and the oil stored in an oil pan provided at the lower part of the engine 1 is pumped up by the oil pump and sent to each part of the engine 1. It is done.
The oil is also sent to the upper part of the cylinder head 2 to lubricate the camshaft 52 and the cam 50.

A part of the oil is scattered in the oil reservoir 70 and the valve tappet 40, and the oil scattered in the oil reservoir 70 is stored in the oil reservoir 70.
In the oil reservoir 70, dusts such as swarf contained in the stored oil settle downward. The oil reservoir 70 is formed with a steeply inclined surface 70a and a wall 70c, so that the deposited dust can be reliably transferred to the lower groove 70b along the inclined portion 70a and the wall 70c. Can be collected. By collecting the garbage in the groove part 70b as described above, it is possible to prevent the precipitated garbage from diffusing in the oil.

  In addition, when the oil water level is stored up to the position of the opening 60a of the tappet guide 60, that is, when a predetermined amount or more is stored, the oil stored in the oil reservoir 70 is It flows into the upper surface of the valve tappet 40 and flows between the valve tappet 40 and the tappet guide 60 for lubrication. Since the oil that flows into the upper surface of the valve tappet 40 in this way is oil on the water surface side where dust has already settled in the oil reservoir 70, the occurrence of dust biting between the valve tappet 40 and the tappet guide 60 is not caused. It is possible to prevent abnormal wear and seizure.

As described above, the cylinder head of the internal combustion engine according to the present invention has good oil flow between the valve tappet 40 and the tappet guide 60 while preventing infiltration of dust in the oil in the direct acting valve system. Can be distributed.
Although the description of the embodiment of the cylinder head of the internal combustion engine according to the present invention is finished above, the embodiment is not limited to the above embodiment.

For example, in the above embodiment, the groove portion 70b is formed in the oil reservoir portion 70, but the groove portion 70b may not be formed, and the oil reservoir portion may be configured only by the inclined portion 70a and the wall portion 70c.
Moreover, in the said embodiment, although the oil reservoir part 70 is formed in the peripheral part of the perimeter of the opening part 60a of the tappet guide 60, it is not restricted to the said perimeter part of the opening part 60a, An oil reservoir part is a tappet guide. It may be formed from a part of 60 openings 60a.

1 is a longitudinal sectional view of a cylinder head of an internal combustion engine according to the present invention. It is a principal part enlarged view of FIG.

Explanation of symbols

1 engine (internal combustion engine)
2 Cylinder head 8 Combustion chamber 10 Intake port 20 Intake valve 20a Umbrella part 20b Stem part 40 Valve tappet 50 Cam 50a Cam peak part 52 Camshaft 60 Tappet guide (guide hole)
60a Opening portion 70 Oil reservoir portion 70a Inclined portion 70b Groove portion 70c Wall portion

Claims (3)

A cylinder head of an internal combustion engine having a valve directly driven by a cam,
A valve tappet interposed between the cam and the valve and slidably received in a guide hole formed in the cylinder head;
The guide hole has an inclined surface that slopes downward from the cam side opening toward the outer side of the internal combustion engine, can store a predetermined amount of oil, and the stored amount of oil exceeds the predetermined amount. In this case, the cylinder head of the internal combustion engine is provided with an oil reservoir portion in which the excess oil is supplied between the guide hole and the valve tappet.   2. The cylinder head for an internal combustion engine according to claim 1, wherein the oil reservoir has a groove recessed downward from a lower end portion of the inclined portion.   3. The cylinder head of the internal combustion engine according to claim 1, wherein the inclined portion is formed at an acute angle with respect to the axial direction of the guide hole.

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