JPS60228713A - Poppet valve - Google Patents

Abstract

PURPOSE:To improve heat resistance of a valve and its corrosion resistance, by mounting a ring made of ceramics, which inserts a brazing material into recesses in side surfaces, into peripheral grooves in a seated part of the valve to be connected with the seated part by melting the brazing material. CONSTITUTION:A poppet valve 1 in its seated part both forms peripheral grooves and prepares rings 2 made of ceramics. The ring 2, providing in its both side surfaces an interrupted or continued recess and inserting a brazing material 3 of wire-shape or in a dust-state into this recess, is mounted to said peripheral groove. Thereafter, the poppet valve 1 is heated to a temperature in which the brazing material 3 is melted and fluidized. The ring 2 is secured to the valve 1 by applying the brazing material 3 to side surfaces of the peripheral groove and forming a convex part protruding into the recess. In this way, a valve of excellent durability is formed by enabling the valve 1 to utilize high hardness, heat resistance and corrosion resistance which are provided in the ceramics.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in mushroom valves used in internal combustion engines such as diesel engines.

Conventionally, mushroom-shaped valves are manufactured by welding a special high-hardness alloy such as Stellite (trade name) onto the seat. That is, as shown in FIG. 3, the conventional mushroom-shaped valve has a mushroom-shaped valve body la, a seat portion 2a, and a stem tip 3a.
It is composed of materials. Of these, the seat portion 2a and the stem tip 3a are overlaid with a special alloy as described above, and have a structure that can withstand harsh environments.

In particular, the seat surface 4a of the seat portion 2a is repeatedly attached to and detached from a valve seat (not shown) depending on the rotational speed of the engine, performing sealing and exhausting functions, and is exposed to the harshest conditions. In particular, with the recent improvements in engine performance, the environment has become increasingly harsh, and the durability of mushroom-shaped valves has become increasingly deteriorating.

In other words, if the durability of the mushroom-shaped valve increases, it will be possible to improve engine performance, making it possible to develop an energy-saving and efficient C engine.

In view of this current situation, the present invention was made in order to improve the durability of the mushroom-shaped valve, particularly the seat surface, and thereby improve the engine performance.

In other words, the present invention is applied to a seat part that is repeatedly attached and detached in a mushroom valve used in an internal combustion engine.

A plurality of circumferential grooves are machined, a ring-shaped ceramic is attached to the groove, and a brazing material is inserted into the recesses machined on both sides of the ceramic and melted.
This mushroom valve is characterized in that the ceramics described above are fixed to a mushroom-shaped valve body through a brazing material.

Next, two aspects of the present invention will be specifically explained.

FIGS. 1 and 2 show two components of the present invention, and are enlarged cross-sectional views of the seat portion of the Kinokodaben. In Figure 1, 1 is a mushroom-shaped valve body, 2 is a ring-shaped ceramic inserted into a groove machined in the seat of the mushroom-shaped valve body, and is generally made of zirconia (ZrO2).
), silicon nitride (S 13 (N4), silicon carbide (S
iC) etc. can be used. 3 indicates a brazing material inserted into recesses provided on both sides of the ring-shaped ceramic 2. Figure 1 shows two grooves cut into the seat and two ring-shaped ceramics inserted.

FIG. 2 similarly shows the case of four pieces as an example. This number is regulated by the size of the Kinoko daben, the width of the seat surface, and the workability of the ceramic ring.

In some cases, one ceramic ring may be used.

A feature of the present invention is to provide an exhaust valve in which heat-resistant, high-hardness ceramics are used to increase the durability of the seat portion of the mushroom-shaped valve, and the ceramics and the mushroom-shaped valve body are fixed together by a special method. It's there to do.

The sheet surface of Kinokodaben is required to have high hardness, excellent heat resistance, corrosion resistance, and a certain degree of toughness. All ceramics have far superior performance than ordinary metals, except for i-type. Therefore, in order to use CeraF,-)cus for the seat surface of the mushroom-shaped valve, the first problem is how to attach the ceramic and the metal (mushroom-shaped valve body). The present invention solves this problem in P4. First, it is applied to both sides of the ceramic ring.

Intermittent or continuous recesses are provided, and a wire-shaped or powdered brazing material is inserted into the recesses and installed in a groove machined in the mushroom-shaped valve body. after that.

Heat to a temperature at which the brazing filler metal into which the Kinoko Daben is inserted melts and flows. The bath-molten brazing filler metal wets the sides of the groove in the mushroom-shaped valve body and is bonded.

It solidifies as it is. In this case, the CeraE Nox and the brazing filler metal are not bonded. Therefore, as a result, a portion of the side surface of the groove formed in the mushroom-shaped valve body protrudes into the recess on the side surface of the ceramic, and the ceramic is fixed.

In this way, it is possible to form a hard ceramic surface in a layered manner on the sheet surface, thereby configuring a sheet surface that takes advantage of the characteristics of ceramics. - Ceramics not only have high hardness, good heat resistance and corrosion resistance, but also generally have
It conducts heat less easily than metal. Therefore, if a part of the seat surface is made of ceramics as in the present invention, heat flowing from the mushroom-shaped valve body is blocked.

In addition, since it repeatedly comes into contact with the valve seat (not shown), heat is taken away from the seat surface of the valve seat, which is maintained at a low temperature, and the temperature of the seat surface 2 decreases, causing a decrease in hardness and increased corrosion. This will improve durability.

As described above, the two aspects of the present invention provide a mushroom daben that has a seat portion with a structure not found in conventional mushroom daben and that can also be significantly improved in durability.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the structure of the seat portion of the mushroom valve according to the present invention, and FIG. 3 is a cutaway view showing the structure of the conventional mushroom valve. 1... Mushroom-shaped valve body, 2... Ring-shaped ceramics, 3... Brazing metal.

Claims (1)

[Claims] In a mushroom-shaped valve used in an internal combustion engine. A plurality of grooves are machined in two circumferential shapes in the seat part that is repeatedly attached and detached, ring-shaped ceramics are attached to the grooves, and a brazing material is inserted into the recesses machined on both sides of the ceramic filter. A mushroom-shaped valve, characterized in that the ceramic is fixed to a mushroom-shaped valve body via a brazing material by melting treatment.