JPH0614001Y2 - Ceramic valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a ceramic valve for intake and exhaust used in an internal combustion engine.

(Prior Art) In recent years, the weight of valve trains has been reduced in line with the increasing performance of internal combustion engines, and the introduction of intake and exhaust valves made of lightweight ceramic that is excellent in heat resistance and wear resistance. Has been considered.

(Problems to be solved by the invention) However, in the above-mentioned conventional one, when a ceramic such as silicon nitride is used for the valve system, especially for the intake and exhaust valves, the valve seat is formed at the edge of the valve face surface. In order to maintain the airtightness by closely contacting the two, the intake and exhaust valves are apt to be chipped or chipped due to vibrations and the like in the high revolution range of the internal combustion engine, and the Young's modulus of the ceramic is
Since it is significantly larger than the currently used heat-resistant steel, its deformation is less likely to occur, and unless the precision is extremely improved in the manufacturing process, a gap is created between the valve face and the valve seat, and sufficient airtightness is maintained. Cannot be achieved, resulting in deterioration of output and fuel consumption. Therefore, this invention solves the above-mentioned drawbacks of the prior art by preventing chipping and chipping of the intake / exhaust valve caused by vibration in a high rotation range, and easily and surely by the intake / exhaust valve. It is intended to maintain airtightness between the face and the valve seat.

(Means for Solving Problems) Therefore, the angle formed by the valve face is set to be equal to or smaller than the angle formed by the valve seat, and the angle difference is set within 1 °.

(Operation) With the above configuration, even if the intake / exhaust valve is displaced due to vibration or the like at the time of high rotation of the internal combustion engine, the space created by the difference in angle between the faces of the valve seat and the valve face In order to prevent chipping or chipping, the contact of the valve face with the valve seat becomes a contact with a certain width rather than an extreme line contact due to initial familiarity. The airtightness in the room can be reliably maintained. If the angle made by the valve face is larger than that of the valve seat, the valve face comes into contact with the seat on the front side of the umbrella. If the angle is 1 ° or more, the contact width cannot be expected to increase due to familiarity, so that the airtightness becomes insufficient.

(Embodiment) The invention will be further described with reference to an embodiment shown in the drawings. (1) is a ceramic valve, and this ceramic valve (1) is a shaft end of the ceramic valve (1) by a rocker arm (7).
Opening and closing by impact on (14), at that time, by the valve stem guide (9) embedded in the cylinder head (13),
The stem part (8) of the ceramic valve (1) is restricted. The valve mechanism is not limited to the one using a rocker arm, but may be a direct type, a swing arm type, or the like. The conical surface (6), which is the outer peripheral edge of the valve face (2), which is the contact surface with the valve seat (4) at the tip of the ceramic valve (1), is made of a heat-resistant alloy valve seat ( By closely contacting the conical surface (5) of 4), the airtightness of the combustion chamber (12) is maintained. Then, the angle formed by the conical surface (6) of the valve face (2) is smaller than the angle formed by the peripheral conical surface (5) of the opening (14) of the valve seat (4), and the angle difference θ ° is , 0 ° ≦ θ
It is assumed that ° ≦ ° 1. Thus, the valve (1)
Conical face (6) of valve face and opening of valve seat (4)
Between the peripheral conical surfaces (5) of (14), a slight gap is generated at the time of contact. That is, when the internal combustion engine rotates at high speed due to the air gap (11) generated when the ceramic valve (1) is closed, the stem portion (8) of the ceramic valve (1) is guided by the valve stem guide (9). The gap (11) absorbs chipping caused by chipping caused by deviation that is regulated and held and vibrated due to vibrations, and prevents these from occurring, and at the same time prevents these from occurring, and also the valve face of the ceramic valve (1) ( The wide contact between 2) and the valve seat (4) maintains its airtightness without being affected by the contact of the ceramic valve (1) during use. (3) is the front surface of the valve (1), and (10) is the suction port.

(Effects of the invention) As described above, since it is configured, it is possible to use a ceramic excellent in heat resistance and light weight by preventing chipping or chipping of the ceramic valve and sufficiently maintaining airtightness. You can achieve chronic weight reduction,
It has an excellent effect that the performance of the internal combustion engine can be remarkably improved by improving the followability of the valve.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a cylinder head of an internal combustion engine equipped with the present invention, and FIG. 2 is an enlarged sectional view of a main part thereof. 1 ... Ceramic valve, 2 ... Valve face, 4 ...
... Valve seat, 5 ... Conical surface of peripheral edge, 6 ... Conical surface of valve tip, 10 ... Suction port, 11 ... Void, 12 ... Combustion chamber, 13 ... Cylinder head.

Claims (1)

[Scope of utility model registration request] 1. A ceramic valve in which the angle formed by the valve face surface is smaller than the angle formed by the valve seat surface on the cylinder head side, and the difference is within 1 °.