JPH08260922A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent the stress from being concentrated to an annular groove part of a shaft part of an engine valve. CONSTITUTION: A bead part 7a of a pair of cotters 7 is fitted to an annular groove 6 formed in a shaft end part of an engine valve, the cotters 7 are fitted into a tightening ring 12 whose inner circumferential surface is of tapered surface to be inclined in the same direction as that of the outer circumferential surface of the cotters 7 so that the lower end of the tightening ring 12 is projected out of the cotters 7, and the projecting end of the tightening ring 12 is abutted on the upper surface of a spring retainer 13 to be pressed against the upper end of a valve spring 9 provided on a cylinder head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating system for an internal combustion engine, which can prevent stress from being concentrated in an annular groove formed in an axial end of an engine valve.

[0002]

2. Description of the Related Art FIG. 3 schematically shows a conventional general valve operating system. (1) is a cylinder head, (2) is an intake or exhaust port, and (3) is a port ( A valve seat press-fitted into the open end of 2) and a valve guide (4) press-fitted into the cylinder head (1).

The valve guide (4) has an engine valve
The shaft portion (5a) of (5) is slidably supported so as to penetrate therethrough, and the umbrella portion (5b) at the lower end abuts the valve seat (3) to close the port (2).

An annular groove (6) formed at the upper end of the shaft (5a)
The inwardly facing bead portion (7a) of the inner peripheral surface of the upper end of the pair of cotters (7) (7) having a half-cylindrical shape is properly fitted to the. Both cotters (7) have a spring retainer with a tapered surface formed on the outer peripheral surface thereof and gradually expanding in diameter upward.
By closely fitting in the tapered hole (8a) of (8), it is firmly fixed to the shaft portion (5a).

Reference numeral (9) is a valve spring (compression coil spring) compressed between the upper surface of the cylinder head (1) and the lower surface of the outward flange (8b) of the spring retainer (8). ) Is always urged upward through the cotter (7).

Reference numeral (10) is a rocker arm for pressing the upper end of the shaft portion (5a), and reference numeral (11) is a lip seal for preventing oil falling.

[0007]

In the above valve operating system, when the engine valve (5) is pressed by the rocker arm (10) to open the port (2), the valve spring
The large load of (9) acts on the spring retainer (8).

Like the conventional spring retainer (8),
When the cotter holding part and the outward brim (8b) are integral with each other, as shown in FIG. 4, the upward load of the valve spring (9) causes a rotational moment as indicated by an arrow to act on the spring retainer (8) to cause the bead to move. A large compressive load acts on the annular groove (6) in which the portion (7a) is fitted. As a result, as shown in the stress distribution diagram, the stress is concentrated near the minimum outer diameter portion of the annular groove (6) of the shaft portion (5a).

In this case, especially in a small engine valve or the like having a small diameter of the shaft portion (5a), there is a possibility that the annular groove (6) may suffer fatigue fracture and the shaft portion may be broken.
The present invention has been made to solve this problem,
An object of the present invention is to provide a valve operating system for an internal combustion engine, which prevents stress from concentrating in the annular groove portion, and thus prevents breakage of the shaft portion and the like.

[0010]

SUMMARY OF THE INVENTION According to the present invention, the above object is to form an annular groove in an axial end portion of an engine valve provided in a cylinder head so as to be slidable in a vertical direction, and the annular groove has an outer periphery. The bead portion of the inner peripheral surface of the pair of cotters having tapered surfaces whose diameters gradually increase upward are fitted so that the inner peripheral surface is in close contact with the outer peripheral surface of the shaft portion. Fit the cotter into a cylindrical tightening ring whose inner peripheral surface is tapered in the same direction as the outer peripheral surface of the cotter, with the lower end of this tightening ring protruding from the lower ends of both cotters. The upper surface of the spring retainer, which is held concentrically with the projecting end of the tightening ring and is concentrically provided below the axial end of the engine valve by penetrating the shaft portion of the engine valve and in pressure contact with the upper end of the valve spring provided on the cylinder head. Abut It is solved by.

[0011]

Since the tightening ring holding both cotters is in contact with the spring retainer only at the lower end, the load from the spring retainer acts only on the tightening ring as an upward force. As described above, the rotation moment acts on the shaft portion and the stress is prevented from being concentrated on the annular groove portion.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same members as those of the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, an annular groove at the upper end of the shaft (5a)
Locked by fitting the bead (7a) to (6) 1
The pair of cotters (7) and (7) are retained by fitting them into a cylindrical tightening ring (12) whose inner and outer peripheral surfaces are tapered surfaces that are inclined in the same direction as the outer peripheral surface of the cotter (7). Has been done. In addition,
The vertical dimension of the tightening ring (12) is slightly larger than that of the cotter (7), and when the two cotters (7) are held, the lower end of the tightening ring (12) is the lower end of the cotter (7). It is designed to project slightly more.

Below the cotter (7) and the tightening ring (12),
It consists of a disc-shaped bottom plate (13a) that penetrates the shaft part (5a), and a spring bearing flange (13b) formed by rising obliquely upward from the outer peripheral edge and horizontally bending the upper end outward. A disc-shaped spring retainer (13) is provided concentrically with the shaft portion (5a). The lower end of the tightening ring (12) is in contact with the upper surface of the bottom plate (13a) of the spring retainer (13).

A valve spring (9) is contracted between the upper surface of the cylinder head (1) and the lower surface of the spring receiving flange (13b) of the spring retainer (13), and the valve spring (9) is an upward spring. The load acts as an inward force on the cotter (7) via the tightening ring (12), so that both cotters (7) are firmly fixed to the shaft portion (5a).

With the above construction, as shown by the arrow in FIG. 2, the load from the spring retainer (13) acts on the tightening ring (12) only as an almost upward force, which is different from the conventional case. Since the rotation moment does not work, the cotter
(7) The whole is pressed substantially uniformly inward by the tightening ring (12).

As a result, as is clear from the stress distribution chart, stress is prevented from concentrating on the annular groove (6), and the annular groove is prevented.
There is no fear that the shaft (5a) will be broken due to fatigue fracture of the (6) part. Of course, the present invention can be applied not only to the rocker arm type valve operating mechanism but also to a direct acting type valve operating mechanism in which a tappet is directly driven by a rotating cam.

[0018]

According to the present invention, the stress due to the rotational moment is prevented from concentrating on the annular groove, so that the annular groove is not likely to be broken due to fatigue damage or the like, and the durability and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a central longitudinal front view showing an embodiment of the present invention.

FIG. 2 is an enlarged half sectional view of an essential part and an explanatory view showing a stress distribution.

FIG. 3 is a central longitudinal front view showing a conventional example.

FIG. 4 is an enlarged half sectional view of an essential part and an explanatory view showing a stress distribution.

[Explanation of symbols]

 (1) Cylinder head (2) Port (3) Valve seat (4) Valve guide (5) Engine valve (5a) Shaft part (5b) Umbrella part (6) Annular groove (7) Cotta (7a) Bead part (9) ) Valve spring (10) Rocker arm (11) Lip seal (12) Tightening ring (13) Spring retainer (13a) Bottom plate (13b) Spring bearing flange

Claims (1)

[Claims] 1. An annular groove is formed in an axial end portion of an engine valve provided on a cylinder head so as to be slidable in a vertical direction, and a tapered surface whose outer peripheral surface gradually increases in diameter is formed in the annular groove. The inner peripheral surface of the pair of cotters is fitted so that the inner peripheral surface is in close contact with the outer peripheral surface of the shaft portion, and both cotters have the same inner peripheral surface as the outer peripheral surface of the cotter. Hold by fitting the lower end of this tightening ring so that the lower ends of the tightening rings project from the lower ends of both cotters, and hold the protruding end of the tightening ring. Of the internal combustion engine, which is concentrically provided below the shaft portion of the engine valve and is brought into contact with the upper surface of a spring retainer which is in pressure contact with the upper end of a valve spring provided on the cylinder head. Valve drive.