JPH0814014A - Valve mechanism for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce damage to and the abrasion of a valve face and a valve seat face while reducing working hours with the uselessness of groove work eliminated and also unifying and lowering the temperature of a intake valve with valve rotation promoted. CONSTITUTION:Plural guide grooves 28, for controlling the peripheral directional rotation of a valve 2 are formed on either of one side or both the sides of a valve stem 3 upper end part outer peripheral surface, sliding with a valve guide 9 upper end part inner peripheral surface, and a valve stem 3 lower end part outer peripheral surface sliding with a valve guide 9 lower end part inner peripheral surface. The guide grooves 28 are composed of an upper groove 28a for promoting the peripheral directional rotation of the valve 2, and a lower groove 28b having appropriate shaft direction width for restraining the peripheral directional rotation of the valve 2. The lower groove 28b is formed along the shaft direction of the valve 2, and the upper groove 28a is formed at a fixed angle or a gradually changing angle to the shaft direction of the valve 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve mechanism of an internal combustion engine, and more particularly to the structure of a valve stem.

[0002]

2. Description of the Related Art As a conventional intake and exhaust valve mechanism for an internal combustion engine, there is, for example, one shown in FIG. 6 (see Japanese Utility Model Laid-Open No. 63-118314). This drawing shows a configuration on the intake valve 2 side that opens and closes by sliding an intake port c, which is a communication port between the intake port a and the combustion chamber b, in the axial direction thereof. The seat 7 is attached. A valve guide 9 for slidingly guiding the valve stem 3 of the intake valve 2 in the axial direction is fitted into the mounting hole 1a formed in the cylinder head 1.

Here, conventionally, if the temperature of a part of the intake valve 2 becomes particularly high, it will cause improper combustion. Therefore, the sliding surface 10 between the valve stem 3 and the valve guide 9 will be described.
One of the two (in this example, the sliding surface on the valve stem 3 side) is formed with a spiral groove 18 for promoting rotation of the intake valve 2 when the intake valve 2 is lifted.
The temperature of the intake valve 2 (particularly the valve umbrella portion 6) is made uniform by effective rotation of.

The exhaust valve has the same structure, and hereinafter, the term "valve" is used to refer to both the intake valve and the exhaust valve.

[0005]

However, in such a conventional valve mechanism, the spiral groove 18 is formed in substantially the entire sliding surface 10 between the valve stem 3 and the valve guide 9, and the spiral groove 18 is formed. Since the formation direction of the groove 18 was a constant direction throughout the whole, there were the following problems.

That is, even if the spiral groove 18 is formed over substantially the entire sliding surface 10 between the valve stem 3 and the valve guide 9, the effect of rotating the valve 2 is not so high, and the spiral groove 18 slides along the sliding surface 10. The structure formed over substantially the entire area is wasteful because the number of processing steps is relatively large, and is inefficient. This is because an appropriate gap is ensured on the sliding surface 10 between the valve 2 and the valve guide 9 so that the valve 2 can slide smoothly. The valve 2 often slides at an angle from the axial direction because the valve 2 is pushed at a position eccentric from the axial center, and the valve 2 is supported by an oil seal above the valve guide 9. This is because even if the stem 3 has the spiral groove 18 in the central portion in the axial direction, a rotational force is not generated so much.

Further, in the conventional configuration, even when the valve 2 is seated, the valve 2 rotates and comes into contact with the valve seat 7, so that carbon or the like is caught between the valve face 5 and the valve seat face 8. In the case of the inclusion, the damage and wear of the valve face surface 5 and the valve seat face surface 8 are increased, and there is a problem that the gas in the combustion chamber is relatively likely to blow through.

In view of the conventional problems as described above, the present invention improves the position of the groove provided in the valve stem and the shape of the groove to eliminate waste of groove processing and reduce the number of processing steps, and at the same time, to improve the valve operation. Where rotation is required, the rotation is promoted to equalize and reduce the temperature of the intake valve, while where valve rotation is not required, valve rotation is suppressed to prevent damage to the valve face and valve seat face. And to reduce wear.

[0009]

Therefore, the invention according to claim 1 is an internal combustion engine which includes a valve and a valve guide for slidingly guiding the valve in the axial direction by a valve stem. In the valve mechanism, at least a valve stem upper end outer peripheral surface that slides with an upper end inner peripheral surface of the valve guide and a valve stem lower end outer peripheral surface that slides with a lower end inner peripheral surface that is separated from the upper end of the valve guide. On the other hand, a plurality of guide grooves for controlling the circumferential rotation of the valve were formed.

According to a second aspect of the present invention, the guide groove includes a lower groove having a predetermined axial width and a remaining upper groove, the lower groove being formed along the axial direction of the valve. Was formed at a constant angle with the axial direction of the bulb. According to a third aspect of the present invention, the guide groove is composed of a lower groove having a predetermined axial width and the remaining upper groove, the lower groove is formed along the axial direction of the valve, and the upper groove is upward. The valve was formed so that the angle with respect to the axial direction of the valve gradually increased.

[0011]

In the invention according to claim 1, an appropriate gap is ensured on the sliding surface between the valve and the valve guide for smooth sliding of the valve, and the rocker for pushing the valve shaft head. Because the arm mainly pushes the position eccentric from the center of the shaft and the valve is supported by the oil seal above the valve guide, the valve often slides at an inclination from the axial direction. At this time, the upper and lower ends of the valve guide are the main parts where the valve and the valve guide slide.

Therefore, if the guide groove is formed in a portion that slides on at least one of the upper end portion and the lower end portion of the valve guide as in this configuration, the rotation of the valve in the circumferential direction can be sufficiently controlled, and it is necessary. By forming the guide groove in the minimum portion, it is possible to reduce the number of processing steps and the like, and to improve efficiency, as compared with the conventional configuration in which the spiral groove is formed over substantially the entire sliding surface.

According to the second aspect of the present invention, if the upper groove for promoting the circumferential rotation of the valve in the guide groove is formed in the portion that slides on at least one of the upper end portion and the lower end portion of the valve guide, It is possible to promote the necessary and sufficient rotation of the valve in the circumferential direction at the time of lifting, and it is possible to make the temperature of the valve, particularly the valve head, uniform and reduced. On the other hand, regarding the shape of the guide groove, if excessive rotation occurs especially when the valve is seated on the valve seat, it is easy to damage the valve face surface and the valve seat face surface by the entrapment of carbon etc. Also grows.

For this reason, it is preferable that the valve has a groove shape such that no rotational force is applied to the valve near the seating time, but according to this configuration, the guide groove slides on the valve guide at the beginning of opening of the valve and near the seating time. The moving lower groove is formed along the axial direction of the valve and acts to suppress the valve rotation.Therefore, excessive rotation does not occur when the valve is seated on the valve seat, and it is possible for carbon to become trapped. It is possible to prevent damage and abrasion of the valve face surface and the valve seat face surface as much as possible.

In the invention according to claim 3, since the rotation of the valve in the circumferential direction is more actively promoted even near the time of maximum lift of the valve, the temperature of the valve can be made uniform and reduced more effectively. You can

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows, as a valve mechanism of an internal combustion engine, an intake valve 2 side that opens and closes by sliding an intake port c, which is a communication port between an intake port a and a combustion chamber b, in the axial direction thereof. The structure in which the valve guide 9 for slidingly guiding the valve stem 3 of the intake valve 2 in the axial direction is fitted into the mounting hole 1a formed in the head 1 is the same as the conventional one.

Further, in this embodiment, one end is swingably supported by the cylinder head 1 via the pivot 20, and the other end is abutted on the upper end of the valve stem 3 to intake the valve 2. The rocker arm 14 that presses and follows the operation of the cam 19 to close the mouth c, and the valve 2
Valve spring 15 that pushes back to open intake port c
A retainer 16 that engages with the upper end of the valve spring 15, a cotter 17 that engages the retainer 16 with the end of the valve stem 3, and a lower end of the valve spring 15 through the valve spring seat 21. And a groove portion 23 to be provided.

Such a structure is the same for the exhaust valve, and hereinafter, the valve will be referred to as both the intake valve and the exhaust valve. Here, in FIG. 1 and FIG. 3, either the outer peripheral surface of the upper end portion of the valve stem 3 that slides on the inner peripheral surface of the upper end portion of the valve guide 9 or the outer peripheral surface of the lower end portion of the valve stem 3 that slides on the inner peripheral surface of the lower end portion of the valve guide 9 is used. A plurality of guide grooves 28 for controlling the rotation of the valve 2 in the circumferential direction is formed in one or both (at least one) (the invention according to claim 1).

The guide groove 28 has an upper groove 28a for promoting the circumferential rotation of the valve 2 and a lower groove 28 having an appropriate axial width for suppressing the circumferential rotation of the valve 2.
b, the lower groove 28b is formed along the axial direction of the valve 2, and the upper groove 28a is formed at a certain angle with respect to a line extending along the axial direction of the valve 2 (claim 2). .

Next, the operation of this structure will be described. On the sliding surface 10 between the valve 2 and the valve guide 9,
An appropriate clearance is ensured for smooth sliding of the valve 2, and the rocker arm 1 for pushing the valve 2 shaft head
4 is pushed at a position eccentric from the center of the shaft, and the valve 2 is supported by the oil seal 13 above the valve guide 9, so that the valve 2 slides while being inclined from the axial direction. In this case, the sliding parts of the valve 2 and the valve guide 9 are mainly the upper end and the lower end of the valve guide 9.

Therefore, as in the present construction, the upper groove 28a for promoting the circumferential rotation of the valve 2 in the guide groove 28.
Is formed in a portion that slides on at least one of the upper end portion and the lower end portion of the valve guide 9, it is possible to promote sufficient rotation in the circumferential direction of the valve 2 during valve lift as shown in FIG. It is possible to make the temperature of the valve 2, in particular, the temperature of the valve head portion 6 uniform and reduced.

In this case, even when the valve 2 slides parallel to the axial direction, the guide groove 2 is formed on the outer peripheral surface of the valve stem 9.
Since 8 is formed, there is no inconvenience and it can be dealt with. On the other hand, regarding the shape of the guide groove 28, if excessive rotation occurs especially when the valve 2 is seated on the valve seat 9, the valve face surface 5 and the valve seat face surface 8 are damaged by the entrapment of carbon or the like. It is easy to do and the amount of wear also becomes large.

For this reason, it is preferable that the valve 2 has a groove shape so that no rotational force is applied to the valve 2 near the time of seating, but according to the present configuration, the guide groove 28 near the beginning of opening of the valve 2 and the time of seating. Since the lower groove 28b that slides with the valve guide 9 is formed along the axial direction of the valve 2, extra rotation does not occur when the valve 2 is seated on the valve seat 7, and the valve is formed by the inclusion of carbon or the like. Damage and wear of the face surface 5 and the valve seat face surface 7 can be prevented as much as possible.

In this way, the guide groove 28 is formed in the minimum necessary portion.
By forming the spiral groove, there is an advantage that efficiency is improved, since there is no waste such as reduction of the processing man-hour and the like, compared with the conventional configuration in which the spiral groove is formed in substantially the entire area of the sliding surface.
Since the guide groove 28 is linear, it is relatively easy to process. Incidentally, as shown in FIG. 4, it is needless to say that the structure of the valve stem 3 similar to that of FIG. 3 can be adopted also in the valve mechanism of the type in which the valve lifter 22 for pressing the valve 2 to close the intake port c is provided. The same actions and effects as described above are achieved.

Next, another embodiment will be described with reference to FIG. In this embodiment, a lower groove 38b of a guide groove 38 formed in the valve stem 3 of the valve 2 is formed along the axial direction of the valve 2 as in the embodiment of FIG. 3, and an upper groove 38a is formed upward. The valve 2 is formed so that the angle with respect to the axial direction gradually increases (the invention according to claim 3).

In this case, the upper groove 38a has a curved and extending shape. With such a configuration, the rotation of the valve 2 in the circumferential direction is more actively promoted even near the maximum lift time of the valve 2, so that the temperature of the valve 2 can be made uniform and reduced more effectively.

[0027]

As described above, according to the first aspect of the invention, the guide groove is formed in the portion that slides on at least one of the upper end and the lower end of the valve guide. Rotation in the circumferential direction can be sufficiently controlled, and by forming the guide groove in the minimum necessary portion, it is possible to reduce the processing man-hours as compared with the conventional configuration in which the spiral groove is formed over substantially the entire sliding surface. It is efficient because it eliminates waste such as

According to the second aspect of the present invention, the upper groove for promoting the circumferential rotation of the valve in the guide groove is formed in a portion that slides on at least one of the upper end and the lower end of the valve guide. Therefore, it is possible to promote sufficient rotation in the circumferential direction of the valve when the valve is lifted, and it is possible to make the temperature of the valve, particularly the valve head uniform, and reduce the temperature, and to start opening the valve in the guide groove. The lower groove that slides with the valve guide near the seating position is formed along the axial direction of the valve and acts to suppress the valve rotation.Therefore, extra rotation occurs when the valve is seated on the valve seat. In addition, the valve face surface and the valve seat face surface can be prevented from being damaged or worn by biting of carbon or the like, and the workability is also good.

According to the third aspect of the invention, since the upper groove of the guide groove is formed so that the angle with respect to the axial direction of the valve gradually increases as it goes upward, the circumferential direction of the valve even in the vicinity of the maximum lift of the valve. Since the rotation of the valve is more positively promoted, the temperature of the valve can be equalized and reduced more effectively.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the invention described in claims 1 and 2.

FIG. 2 is a cross-sectional view for explaining the operation status of the above embodiment.

FIG. 3 is a front view of a valve in the above embodiment.

FIG. 4 is a sectional view of another embodiment.

FIG. 5 is a sectional view of an embodiment of the invention according to claim 3;

FIG. 6 is a sectional view of a conventional device.

[Explanation of symbols]

 2 valve 3 valve stem 9 valve guide 10 sliding surface 28 guide groove 28a upper groove 28b lower groove 38 guide groove 38a upper groove 38b lower groove

Claims (3)

[Claims] 1. A valve mechanism of an internal combustion engine comprising a valve and a valve guide for slidingly guiding the valve in an axial direction by a valve stem, wherein the valve mechanism slides on an inner peripheral surface of an upper end portion of the valve guide. A plurality of guides for controlling the rotation of the valve in the circumferential direction are provided on at least one of the outer peripheral surface of the valve stem upper end and the inner peripheral surface of the lower end of the valve stem which is separated from the upper end of the valve guide. A valve mechanism for an internal combustion engine, wherein a groove is formed. 2. The guide groove comprises a lower groove having a predetermined axial width and a remaining upper groove, the lower groove being formed along the axial direction of the valve, and the upper groove being constant with the axial direction of the valve. The valve mechanism for an internal combustion engine according to claim 1, wherein the valve mechanism is formed with an angle of. 3. The guide groove comprises a lower groove having a predetermined axial width and a remaining upper groove, the lower groove being formed along the axial direction of the valve, and the upper groove of the valve increasing upward. 2. The valve mechanism for an internal combustion engine according to claim 1, wherein the valve mechanism is formed so that the angle with respect to the axial direction gradually increases.