JP2000161021A - Valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve system for an internal combustion engine, which can reduce noise by preventing occurrence of the colliding noise of a valve stem. SOLUTION: An engine valve 3 is arranged which can open and close the intake or exhaust port 2 of an internal combustion engine. A valve guide 4 is arranged which can slidably guide the valve stem 5 of the engine valve 3. A rotary cam 11 is arranged by which the engine valve 3 is operated in opening and closing. A lifter 5 slidably guided to the inside of a storage hole 18 formed in a cylinder head 1 is arranged between the rotary can 11 and the valve stem 5 of the engine valve 3. One of contact surfaces of the bottom surface 21 of the lifter 15 with the end surface 22 of the valve stem 5 is formed into a spherical projected surface, and the other is formed into a recessed surface brought into contact with one projected surface, and also the center C of the spherical projected surface is coincident with an intersection of the axis Yl of the lifter 15 and diagonal lines LC connecting the peripheral end parts of the lifter 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a valve train for an internal combustion engine.

[0002]

2. Description of the Related Art This type of valve train for an internal combustion engine includes an engine valve capable of opening and closing an intake or exhaust port of the internal combustion engine, a valve guide for slidably guiding a valve stem of the engine valve, and an engine valve. And a lifter disposed between the rotary cam, the valve stem of the engine valve, and the rotary cam, and slidably guided into a receiving hole formed in the cylinder head.

The lifter slides in the receiving hole according to the lift amount of the rotary cam to open and close the engine valve. At this time, since the lifter is slidably guided into the accommodation hole formed in the cylinder head, the lifter has an appropriate sliding gap between the lifter and the accommodation hole. There is a risk of turning inside.

If the engine valve is opened / closed while the lifter is rotated, the valve stem of the engine valve is tilted and the opening / closing operation of the engine valve becomes unstable. Kaihei 3-9
Japanese Patent Publication No. 7506 proposes a valve gear in which one of contact surfaces between a bottom surface of a lifter and an end surface of a valve stem has a spherical convex surface, and the other has a rotating spherical concave surface in linear contact with one convex surface. Have been.

[0005]

However, in the prior art, the center of rotation of the lifter when the bottom surface of the lifter is in contact with the end surface of the valve stem is in the free state of the lifter (when the bottom surface of the lifter is the valve). Does not match the center of rotation in the state in which it is not in contact with the end face of the stem).

Therefore, when the engine valve is to be opened and closed with the lifter turned, the center of rotation of the lifter moves slightly when the outer peripheral end of the lifter comes into contact with the housing hole. A force will be generated to tilt the engine valve. As a result, the valve stem of the engine valve is inclined, and may collide with a valve guide that guides the valve stem, thereby generating a collision noise.

The present invention has been devised in view of the above conventional circumstances, and provides a valve train for an internal combustion engine capable of preventing the occurrence of collision noise of a valve stem and reducing noise. The purpose is to do.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an engine valve capable of opening and closing an intake or exhaust port of an internal combustion engine, and a valve guide for slidably guiding a valve stem of the engine valve. A rotating cam for opening and closing the engine valve, and a lifter disposed between the rotating cam and the valve stem of the engine valve and slidably guided into a receiving hole formed in the cylinder head. In the valve train of an internal combustion engine, one of the contact surfaces between the bottom surface of the lifter and the end surface of the valve stem is a spherical convex surface, and the other is a concave surface in contact with the one convex surface, and the center of the spherical convex surface. However, the configuration matches the intersection of the axis of the lifter and a diagonal line connecting the outer peripheral end of the lifter.

In such a configuration, the rotation of the rotary cam causes the engine valve to open and close via the lifter. At this time, the lifter may rotate within the range of the sliding gap due to the sliding gap between the lifter and the housing hole.

When the engine valve is opened and closed with the lifter turned, the center of the spherical convex surface formed on one of the contact surfaces between the bottom surface of the lifter and the end surface of the valve stem is the axis of the lifter. And the diagonal line connecting the outer peripheral end of the lifter coincides with the intersection of the lifter, so that the lifter rotates in the same manner as in the free state, and the center of rotation moves even if the outer peripheral end of the lifter contacts the receiving hole. Never.

Therefore, when the lifter rotates,
Since the center of rotation does not move and the valve stem of the engine valve does not tilt, the valve stem does not collide with the valve guide.

Therefore, a valve train for an internal combustion engine that can reduce noise by preventing collision noise of the valve stem can be obtained.

[0013]

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

FIG. 1 is a sectional view of a valve train of an internal combustion engine showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing a main part of FIG.

In FIG. 1, reference numeral 1 denotes a cylinder head of an internal combustion engine, and reference numeral 2 denotes an intake or exhaust port (hereinafter simply referred to as a port) formed in the cylinder head 1.

Reference numeral 3 denotes an engine valve. The engine valve 3 is seated on a valve seat 4 provided at an end of a port 2 of the internal combustion engine, and the port 2 can be opened and closed. In the engine valve 3, a valve stem 5 of the engine valve 3 is slidably guided by a valve guide 6.

Reference numeral 7 denotes a valve spring. The valve spring 7 is disposed between the cylinder head 1 and a spring receiver 8 attached to the valve stem 5, and constantly urges the engine valve 3 in the port 2 closing direction. I have.

Reference numeral 11 denotes a rotating cam for opening and closing the engine valve 3. The rotary cam 11 has a lift portion 13 formed on the outer circumference of a reference circle 12. The rotation center of the rotary cam 11 is the axis Ys of the valve stem 5.
Are arranged so as to approximately match.

Reference numeral 15 denotes a lifter disposed between the valve stem 5 of the engine valve 3 and the rotary cam 11.
The lifter 15 includes a cylindrical lifter main body 16 and a shim 17 provided on the top surface of the lifter main body 16, and is slidably accommodated in an accommodation hole 18 formed in the cylinder head 1. In a normal state, the axis Yl of the lifter 15 coincides with the axis Ys of the valve stem 5 and the rotation center of the rotary cam 11.

The bottom surface 21 of the lifter 15 is in contact with the end surface 22 of the valve stem 5, and one of these contact surfaces, the end surface 22 of the valve stem 5 in this embodiment, is a spherical convex surface, and the other is Contact surface, ie, lifter 1
The bottom surface 21 of the valve stem 5 is a concave surface in contact with the convex surface of the valve stem 5. The center C of the spherical convex surface formed on the end surface 22 of the valve stem 15 is the axis C1 of the lifter 15.
And a diagonal line Lc connecting the outer peripheral end of the lifter 15 with the intersection (see FIG. 2).

In such a configuration, the rotation of the rotary cam 11 causes the engine valve 3 to open and close via the lifter 15. At this time, the lifter 15 may rotate within the range of the sliding gap due to the sliding gap between the lifter 15 and the housing hole 18.

When opening and closing the engine valve 3 with the lifter 15 rotated, the bottom surface 21 of the lifter 15
Of the contact surface between the valve stem 5 and the end surface 22 of the valve stem 5, the center C of the spherical convex surface formed on the end surface 22 of the valve stem 5.
Coincides with the intersection of the axis Yl of the lifter 15 and a diagonal line Lc connecting the outer peripheral end of the lifter 15.
5 rotates similarly to the free state, and the center of rotation does not move even if the outer peripheral end of the lifter 15 contacts the housing hole 18.

Therefore, when the lifter 15 rotates, the center of rotation does not move, and the engine valve 3
Of the valve stem 5 does not tilt, so that the valve stem 5 does not collide with the valve guide 6.

Accordingly, it is possible to obtain a valve gear for an internal combustion engine capable of preventing the occurrence of collision noise of the valve stem 5 and reducing noise.

FIG. 3 is a view showing another embodiment of the present invention. This embodiment is different from the above embodiment in that a contact surface between a bottom surface 21 of the lifter 15 and an end surface 22 of the valve stem 5 is provided. It is the shape of.

That is, one of the contact surfaces between the bottom surface 21 of the lifter 15 and the end surface 22 of the valve stem 5, in this embodiment, the bottom surface of the lifter 15 is a spherical convex surface, and the other contact surface is That is, the end surface 22 of the valve stem 5 is a concave surface that is in contact with the convex surface of the bottom surface 21 of the lifter 15.
Further, the center C of the spherical convex surface formed on the bottom surface 21 of the lifter 15 matches the intersection of the axis Yl of the lifter 15 and the diagonal line Lc connecting the outer peripheral end of the lifter 15.

Also in this configuration, of the contact surface between the bottom surface 21 of the lifter 15 and the end surface 22 of the valve stem 5, the center C of the spherical convex surface formed on the bottom surface 21 of the lifter 15 is aligned with the axis of the lifter 15. Since the center line Yl and the diagonal line Lc connecting the outer peripheral end of the lifter 15 coincide with each other, the lifter 15 rotates similarly to the free state, and even if the outer peripheral end of the lifter 15 contacts the accommodation hole 18. The center of rotation does not move.

Therefore, when the lifter 15 rotates, the center of rotation does not move, and the engine valve 3
Of the valve stem 5 does not tilt, so that the valve stem 5 does not collide with the valve guide 6.

Therefore, also in this embodiment,
Preventing the collision sound of the valve stem 5 from occurring,
A valve train for an internal combustion engine capable of reducing noise is obtained.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment, and can be changed without departing from the spirit of the invention.
For example, a tip made of a wear-resistant material may be provided on one or both of the contact surfaces between the bottom surface 21 of the lifter 15 and the end surface 22 of the valve stem 5.

[0031]

As described above in detail, according to the present invention, a valve train for an internal combustion engine capable of preventing the occurrence of a collision noise of a valve stem and reducing noise can be obtained. Can be

[Brief description of the drawings]

FIG. 1 is a sectional view of a valve gear of an internal combustion engine showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of FIG.

FIG. 3 is a drawing similar to FIG. 2, showing another embodiment of the present invention.

[Explanation of symbols]

 2 Port 3 Engine valve 5 Valve stem 6 Valve guide 11 Rotating cam 15 Lifter 18 Housing hole 21 Bottom surface 22 End surface

Claims (1)

[Claims] 1. An engine valve capable of opening and closing an intake or exhaust port of an internal combustion engine, a valve guide for slidably guiding a valve stem of the engine valve, a rotary cam for opening and closing the engine valve, and a rotation of the engine. A valve operating device for an internal combustion engine, comprising: a lifter disposed between a cam and a valve stem of an engine valve and slidably guided in a receiving hole formed in a cylinder head.
Of the contact surfaces between the bottom surface of the lifter and the end surface of the valve stem, one is a spherical convex surface, the other is a concave surface in contact with the one convex surface, and the center of the spherical convex surface is the axis of the lifter and the lifter. A valve operating device for an internal combustion engine, which coincides with an intersection with a diagonal line connecting outer peripheral ends of the internal combustion engine.