JP2017008836A - Engine valve and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine valve having high heat insulation and preventing a glass coat layer formed on the umbrella part of an engine valve from peeling from a metal substrate.SOLUTION: An engine valve comprises a metal substrate comprising a shaft part and a pedestal part, and a ceramic member. The pedestal part comprises a column part and an umbrella skirt part. A portion other than the umbrella skirt part of the umbrella rear surface of the engine valve is made of the ceramic member. The column art is fitted to a space formed inside the ceramic member to constitute the umbrella part of the engine valve. The ceramic member is bonded to the umbrella skirt part of the metal substrate through the glass coat layer, and integrated therewith.SELECTED DRAWING: Figure 1

Description

The present invention relates to an engine valve and a manufacturing method thereof.

In a vehicle such as an automobile equipped with an engine, a large amount of heat is generated in the engine part. It is.

Therefore, researches have been actively conducted to effectively use the heat generated in the engine and improve characteristics such as fuel efficiency, and attempts have been made to insulate engine valves in order to reduce heat loss. It has been broken.

Patent Document 1 discloses a technique for heat insulation of an engine valve, in which a film is formed by spraying ceramics or an alloy on the umbrella front and back of the valve. Patent Document 2 discloses a paint for exhaust system parts that is a technique for achieving heat insulation and is applied to a base material made of metal.

JP 2003-307105 A International Publication No. 2014/034395

However, in Patent Document 1, since the coating is formed by thermal spraying, the adhesion between the metal engine valve and the coating cannot be said to be sufficient. During engine operation, engine valves are subject to significant thermal and physical shocks. Under the harsh environment in which such an engine valve is used, the technique of Patent Document 1 has a problem that the film peels from the engine valve.

When a coating film is formed on a base material made of metal using the paint for exhaust system parts of Patent Document 2, since the glass component is baked on the base material made of metal, the metal component and the glass component are chemically bonded to each other. Good adhesion can be ensured. However, the technique of Patent Document 2 has a problem that the film shrinks when a film containing a glass component is baked to form the film. This is a phenomenon that occurs due to the difference in thermal expansion coefficient between the metal and the film, and this shrinkage phenomenon becomes significant when the film thickness is large. Due to this contraction, there is a problem that the end of the formed film is drawn (retracted) toward the center of the film, and the thickness of the film is reduced at the end. Therefore, even if the above-mentioned film is formed on the umbrella part of the engine valve for the purpose of improving heat insulation, for example, the end part of the film on the umbrella hem side can be drawn toward the shaft part side, and the film on the end part becomes thin. End up. Thus, if there is a thin portion in the film, the heat insulating performance of the portion is inferior, and therefore sufficient heat insulating performance cannot be exhibited.

The present invention has been made in view of the above-described problems, and provides an engine valve that has high heat insulating properties and that makes it difficult for the glass coat layer formed on the umbrella portion of the engine valve to peel off from the metal substrate. With the goal.

In order to achieve the above object, an engine valve according to a first aspect of the present invention is an engine valve composed of a metal base material including a shaft portion and a base portion, and a ceramic member, wherein the base portion includes a columnar portion and an umbrella skirt. The portion other than the umbrella hem portion on the back of the umbrella of the engine valve is made of the ceramic member, and the columnar portion is joined to a space formed inside the ceramic member so that the engine valve An umbrella portion is configured, and the ceramic member is bonded to and integrated with an umbrella skirt portion of the metal base material through a glass coat layer.

As described above, the columnar part of the metal base material is combined in the space formed inside the ceramic member, so that a part other than the umbrella hem part of the umbrella part of the engine valve is configured. Hereinafter, the engine valve of the present invention is also referred to as a shaft-combined engine valve.

An engine valve according to a second aspect of the present invention is an engine valve composed of a metal base material including a shaft portion and a truncated cone-shaped base portion and a ceramic member, and an umbrella skirt portion on the back surface of the umbrella of the engine valve. The other part is composed of the ceramic member, and a part of the base part is combined in a space formed inside the ceramic member to constitute an umbrella part of the engine valve. It is characterized by being bonded to and integrated with the base portion of the metal substrate through a glass coat layer.

As described above, parts of the base part of the truncated cone shape of the metal base material are combined with the space formed inside the ceramic member, so that the parts other than the umbrella hem part of the umbrella part of the engine valve are configured. Hereinafter, the engine valve of the second aspect of the present invention is also referred to as an umbrella united engine valve.
In the following, the term “engine valve of the present invention” refers to both the shaft united engine valve and the umbrella united engine valve of the present invention. When it is necessary to specify and explain which invention is one of the inventions, the description will be made by specifying the shaft unit-combined engine valve and the umbrella unit-combined engine valve.

Here, the umbrella back surface of the engine valve of the present invention is the side surface of the engine valve umbrella. The said umbrella back surface is also a surface which connects the axial part of an engine valve, and the umbrella surface. When the engine valve of the present invention is used in an engine, the back surface of the umbrella is a surface that does not face the engine combustion chamber in a state where the engine valve is closed in the umbrella portion of the engine valve. The umbrella surface of the engine valve is a surface facing the engine combustion chamber in the umbrella portion of the engine valve with the engine valve closed.

The umbrella hem part of the engine valve of the present invention is a part of the umbrella hem that is continuous with the umbrella surface in the umbrella part of the engine valve, and is a part of the umbrella part. The umbrella skirt portion on the back surface of the umbrella is the surface of the umbrella skirt portion constituting the back surface of the umbrella. The part other than the umbrella skirt portion on the back surface of the umbrella of the engine valve is the back surface of the umbrella from the shaft side end of the umbrella skirt portion to the shaft portion of the engine valve.
When the engine valve of the present invention is used in an engine, the umbrella skirt portion on the back surface of the umbrella is a portion in contact with the cylinder. The umbrella back surface of the umbrella part of the engine valve of the present invention is made of a ceramic member except for the umbrella skirt part, and the umbrella skirt part is made of a part of the base part of the metal substrate.
Therefore, the umbrella back surface of the umbrella part of the engine valve of the present invention is composed of a part other than the umbrella skirt part constituted by the ceramic member and an umbrella skirt part constituted by a part of the base part of the metal substrate. The shaft portion of the engine valve is constituted by a shaft portion of a metal base material.

In the shaft unit-combined engine valve of the present invention, the part other than the umbrella skirt part of the umbrella part is composed of a ceramic member and a columnar part of a metal base material incorporated into the ceramic member. In the shaft unit-combined engine valve, the periphery of the columnar portion of the metal base material is covered with a ceramic member, and the ceramic member is bonded to the umbrella skirt portion of the metal base material through a glass coat layer. It is integrated with the metal substrate.

In the umbrella unit-combined engine valve, the part other than the umbrella skirt part of the umbrella unit is composed of a ceramic member and a part of a truncated cone-shaped base portion of a metal base material that is fitted inside the ceramic member. In the umbrella unit-integrated engine valve, the shaft side of the side surface of the truncated cone-shaped base portion of the metal base material is covered with a ceramic member, and the ceramic member is formed on the metal base material via the glass coat layer. It is bonded to a part of the truncated cone-shaped base and integrated with the metal substrate.

In the engine valve of the present invention, the back surface of the umbrella other than the umbrella skirt is made of the ceramic member, and glass is interposed between the ceramic member and the metal base material forming the umbrella portion of the engine valve. Since the coat layer is formed, it is possible to improve the heat insulation of the portion from the end portion on the shaft portion side of the umbrella skirt portion on the back surface of the umbrella of the engine valve to the shaft portion of the engine valve.

In the umbrella part of the engine valve of the present invention, the ceramic member is integrally bonded to the base part of the metal base material through a glass coat layer. For this reason, in the engine valve of the present invention, the ceramic member covers the entire surface of the glass coat layer. Thereby, even if it passes through the sintering process for forming a glass coat layer at the time of manufacture, the edge part of the glass coat layer which comprises the umbrella part of an engine valve does not generate | occur | produce. This is because the ceramic member does not easily shrink even after the sintering process, and the weight of the ceramic member inhibits the shrinkage of the glass coat layer. For this reason, the problem that the thickness of the glass coat layer constituting the umbrella part of the engine valve becomes thin at the end portion does not occur, and a glass coat layer having a sufficient thickness is also formed in the part adjacent to the umbrella hem part of the engine valve. Can be formed. As a result, the engine valve can exhibit high heat insulation performance.

Further, in the engine valve of the present invention, when the glass coat layer is formed by sintering, strong adhesion is developed between the metal substrate and the glass coat layer and between the glass coat layer and the ceramic member. For this reason, even in a harsh environment where the engine valve is used, the glass coat layer formed on the umbrella portion of the engine valve is difficult to peel off from the metal base material, and high heat insulation performance can be exhibited.

The engine valve of the present invention has high heat insulation. Therefore, the following effects are exhibited.
When the engine valve of the present invention is used for an engine, the engine valve of the present invention can be used as both an intake side engine valve and an exhaust side engine valve.
When the engine valve of the present invention is used as an engine valve on the intake side, the engine valve of the present invention has high heat insulation, so that the heat of the engine valve is not easily transmitted to the intake air. Therefore, the engine can be operated without reducing the intake efficiency.
Further, when the engine valve of the present invention is used as an engine valve on the exhaust side, the engine valve of the present invention has high heat insulation properties, so that the heat of the exhaust is not easily transmitted to the engine valve. Therefore, the temperature of the exhaust gas is unlikely to decrease. Exhaust gas from the engine is purified by a carrier installed in an exhaust gas purification device installed downstream of the engine. If the temperature of the exhaust gas is not lowered, the exhaust gas quickly raises the temperature of the carrier. The exhaust gas purification function of the carrier can be suitably exhibited. That is, when the engine valve of the present invention is used as an engine valve on the exhaust side, exhaust gas purification efficiency is improved.

In the umbrella part-combined engine valve of the present invention, when the total volume of the ceramic member and the space formed therein is 100%, the ratio of the volume of the ceramic member to the total volume is 50 to 50%. 90% is preferable, and 80 to 90% is more preferable.
In the umbrella part-combined engine valve, when the ratio of the volume of the ceramic member to the total volume is 50 to 90%, from the end part on the shaft part side of the umbrella skirt part to the shaft part of the engine valve, The back of the umbrella of the engine valve can exhibit higher heat insulation performance. Therefore, when the engine valve of the present invention has the above configuration, the above-described effects of the present invention can be more fully exhibited.

As the umbrella unit-combined engine valve, for example, a cone in which a metal base composed of a shaft part and a truncated cone-shaped base part and a space where a part of the base part of the metal base part is joined is formed. An engine valve formed of a ceramic member having a shape (hereinafter referred to as a skirt shape) obtained by cutting a surface layer portion having a predetermined thickness on a table is mentioned. The umbrella portion of such an engine valve is configured by combining the base portion of the metal base material in a space formed inside the skirt-shaped ceramic member, and the lower surface of the ceramic member is The metal substrate and the ceramic member are integrated by adhering to the umbrella base of the metal substrate via the glass coat layer.

Further, in the shaft-combined engine valve of the present invention, when the total volume of the ceramic member and the space formed therein is 100%, the ratio of the volume of the ceramic member to the total volume is: It is preferable that it is 50 to 90%, and it is more preferable that it is 70 to 80%.
When the ratio of the volume of the ceramic member to the total volume is 50 to 90% in the shaft-combined engine valve, the shaft portion side end portion of the umbrella hem portion of the engine valve umbrella portion The portion up to the shaft portion is mainly composed of a ceramic member, and the ceramic member is bonded and integrated with the umbrella skirt portion of the metal substrate through the glass coat layer. For this reason, the part from the edge part by the side of the shaft part of the umbrella bottom part of the umbrella part of an engine valve to the shaft part of an engine valve can exhibit higher heat insulation performance. Therefore, when the engine valve of the present invention has the above configuration, the above-described effects of the present invention can be more fully exhibited.

As the shaft unit-combined engine valve, for example, a frustum-shaped ceramic member in which a metal base composed of a shaft unit, a columnar unit, and an umbrella skirt, and a space in which the columnar unit is combined is formed inside. An engine valve consisting of The umbrella part of such an engine valve is configured such that the columnar part of the metal base material is combined in a space formed inside the ceramic member, and the bottom surface of the ceramic member is interposed through the glass coat layer. Then, the metal base material and the ceramic member are integrated by bonding to the umbrella base of the metal base material.

In the engine valve of the present invention, the ceramic member preferably has pores.
When the ceramic member has pores, the heat insulating performance of the engine valve is further improved. Moreover, even if a stress due to a difference in thermal expansion occurs between the glass coat layer and the ceramic member in the sintering step when forming the glass coat layer, the stress is relieved by the pores. For this reason, even if the toughness of the glass coat layer is low, the ceramic member is more prevented from being damaged by absorbing stress during sintering.
Moreover, it is preferable that the component of the glass coat layer has penetrated into the pores of the ceramic member. In the sintering process, the glass coat layer raw material diffuses into the pores and exhibits an anchor effect, whereby stronger adhesion between the glass coat layer and the ceramic member is possible.

In the engine valve of the present invention, the glass coat layer preferably has pores.
When the glass coat layer has pores, the heat insulating performance of the engine valve is further improved. Moreover, even if a stress due to a difference in thermal expansion occurs between the glass coat layer and the ceramic member in the sintering step when forming the glass coat layer, the stress is relieved by the pores. For this reason, even if the toughness of the glass coat layer is low, the glass coat layer is prevented from being broken and broken in the sintering process.

In the engine valve of the present invention, the glass coat layer preferably has a thickness of 10 to 500 μm.
If the thickness of the glass coat layer is less than 10 μm, the heat insulation of the engine valve may not be sufficiently improved. When the thickness of the glass coat layer exceeds 500 μm, cracks may easily occur when a thermal shock or the like is applied to the glass coat layer.

In the engine valve of the present invention, the width of the umbrella skirt is 3 to 20% of the width of the engine valve back in the direction from the umbrella skirt on the engine valve back to the shaft of the engine valve. Preferably there is.
When the width of the umbrella skirt is within the above range, when the engine valve of the present invention is used in an engine, the portion of the engine valve that comes into contact with the valve seat can be made sufficiently large. It is possible to prevent the engine valve from being destroyed by an impact caused by repeated collisions. Moreover, since the ratio of the umbrella part coat | covered with a glass coat layer can be enlarged enough, sufficient heat insulation effect can be acquired.
In this specification, “the direction from the umbrella hem on the back of the umbrella of the engine valve toward the shaft” refers to a straight line that connects the engine valve shaft to the shaft of the engine valve at the shortest distance. Means the direction of

Moreover, it is preferable that the area of the umbrella skirt part in the back surface of the umbrella of the engine valve is 5 to 50% of the area of the back surface of the umbrella of the engine valve.
In the engine valve, when the area of the umbrella skirt is less than 5% of the area of the back of the umbrella of the engine valve, when the engine valve of the present invention is used in an engine, the portion of the engine valve that contacts the cylinder is small. Become. Since the engine valve and the cylinder repeatedly collide, when the umbrella skirt becomes small, the impact per unit area at the umbrella skirt becomes strong. Therefore, when the area of the umbrella skirt is less than 5% of the area of the back surface of the umbrella of the engine valve, the engine valve is easily broken.
In the engine valve, when the area of the umbrella skirt exceeds 50% of the area of the back surface of the engine valve, the ratio of the back surface of the umbrella made of a ceramic member decreases. Therefore, it becomes difficult to obtain a sufficient heat insulating effect.

The glass coat layer is preferably made of an amorphous inorganic material and a crystalline inorganic material.
The amorphous inorganic material functions as a glass layer that covers the metal substrate of the engine valve. Further, the crystalline inorganic material plays a role as a member for improving heat resistance. Further, the presence of the amorphous inorganic material and the crystalline inorganic material in the glass coat layer increases the strength of the glass coat layer.

In the engine valve of the present invention, the amorphous inorganic material is preferably a low softening point glass having a softening point of 300 to 1000 ° C.
When the amorphous inorganic material is the above-mentioned low softening point glass, the amorphous inorganic material is softened and melted by heating at a temperature exceeding the softening point and spreads on the surface of the metal substrate to form a glass coat layer.

In the engine valve of the present invention, the crystalline inorganic material is preferably made of at least one selected from the group consisting of alumina, zirconia, yttria, calcia, magnesia, ceria and hafnia.
The glass coat layer containing the crystalline inorganic material having excellent heat resistance performance is improved in heat resistance. Also, the heat insulation performance is improved.

In the engine valve of the present invention, the ceramic member is preferably made of zirconia.
A ceramic member made of zirconia is preferable because of its excellent heat resistance. Zirconia is preferable because of its good adhesion to the glass coat layer.

A method for manufacturing an engine valve according to a first aspect of the present invention includes: a glass paste layer forming step of forming a glass paste layer by applying a glass paste to an umbrella skirt constituting the base portion of the metal base; A ceramic member disposing step of disposing the ceramic member on the surface of the glass paste layer and sintering the glass paste layer while fitting the columnar portion constituting the metal base material into the formed space. Thus, the method includes forming a glass coat layer and bonding the ceramic member and the umbrella skirt portion of the metal base material via the glass coat layer.

In the engine valve manufacturing method of the first aspect of the present invention, the ceramic member is disposed on the surface of the glass paste layer formed on the umbrella skirt portion constituting the base portion of the metal substrate. Thereby, even if it passes through sintering for forming a glass coat layer, the end part of the glass coat layer which constitutes the umbrella part of an engine valve does not become closed. For this reason, the problem that the thickness of the glass coat layer constituting the umbrella portion of the engine valve becomes thin at the end portion does not occur, and a glass coat layer having a sufficient thickness is formed even in the portion adjacent to the umbrella skirt portion. Can do. As a result, an engine valve that can exhibit high heat insulation performance can be manufactured.

In the manufacturing method of the engine valve according to the first aspect of the present invention, the ceramic base material is disposed on the surface of the glass paste layer formed on the umbrella base of the metal base material, and then the glass paste layer is sintered. Strong adhesion between the glass coat layer and the glass coat layer and between the glass coat layer and the ceramic member is exhibited. For this reason, according to the method for manufacturing an engine valve of the present invention, it is possible to manufacture an engine valve that has high heat insulating properties and the glass coat layer formed on the umbrella portion of the engine valve is difficult to peel off from the metal substrate.

The engine valve manufacturing method according to the second aspect of the present invention includes a glass paste layer forming step of forming a glass paste layer by applying a glass paste to the surface of the base portion of the metal base, and a space formed inside the ceramic member. The glass base layer is inserted into the base of the metal base, and the ceramic member is disposed on the surface of the glass paste layer, and the glass paste layer is sintered to sinter the glass coat layer. And forming an adhesion step of bonding the ceramic member and the base portion of the metal substrate through the glass coat layer.

In the engine valve manufacturing method according to the second aspect of the present invention, the ceramic member is disposed on the surface of the glass paste layer formed on the surface of the base portion of the metal substrate. Thereby, even if it passes through sintering for forming a glass coat layer, the end part of the glass coat layer which constitutes the umbrella part of an engine valve does not become closed. For this reason, the problem that the thickness of the glass coat layer which comprises the umbrella part of an engine valve becomes thin does not generate | occur | produce, but the glass coat layer of sufficient thickness can be formed in the surface of the said base part. As a result, an engine valve that can exhibit high heat insulation performance can be manufactured.

In the method for manufacturing an engine valve according to the second aspect of the present invention, the ceramic base is disposed on the surface of the glass paste layer formed on the surface of the base portion of the metal substrate, and then the glass paste layer is sintered, thereby obtaining a metal substrate. Strong adhesion is developed between the material and the glass coat layer and between the glass coat layer and the ceramic member. For this reason, according to the method for manufacturing an engine valve of the present invention, it is possible to manufacture an engine valve that has high heat insulating properties and the glass coat layer formed on the umbrella portion of the engine valve is difficult to peel off from the metal substrate.

The ceramic member used for the engine valve is the engine valve of the present invention.
For this reason, the engine valve using the ceramic member can exhibit high heat insulation performance.

Fig.1 (a) is a perspective view which shows an example of the engine valve of this invention, FIG.1 (b) is the sectional view on the AA line of the engine valve shown to Fig.1 (a). Fig.2 (a) is a perspective view which shows another example of the engine valve of this invention, FIG.2 (b) is a BB sectional drawing of the engine valve shown to Fig.2 (a). FIG. 3 is a cross-sectional view schematically showing an example of the structure of an engine combustion chamber in which the engine valve of the present invention is used. FIG. 4A is a perspective view showing the shape of the ceramic member according to the first embodiment, and FIG. 4B is a perspective view showing the shape of the ceramic member according to the second embodiment.

Detailed Description of the Invention
Hereinafter, the engine valve of the present invention will be described in detail.

The engine valve of the first aspect of the present invention includes the following configuration.
That is, the shaft united engine valve of the present invention is an engine valve composed of a metal base material including a shaft part and a base part and a ceramic member, and the base part includes a columnar part and an umbrella skirt part. The portion other than the umbrella hem on the back of the umbrella of the engine valve is made of the ceramic member, and the columnar portion is joined to the space formed inside the ceramic member so that the umbrella portion of the engine valve is The ceramic member is bonded to and integrated with an umbrella skirt portion of the metal substrate through a glass coat layer.

The shaft unit-combined engine valve of the present invention comprises a rod-shaped shaft part, a conical umbrella part, and an umbrella hem part which is an umbrella hem part of the umbrella part. The material includes a shaft portion and a base portion, and the base portion further includes a columnar columnar portion and a disk-shaped umbrella skirt portion. Further, regarding the shaft portion and the umbrella skirt portion of the engine valve, the shaft portion and the umbrella skirt portion of the metal substrate are used as they are as the shaft portion and the umbrella skirt portion.

On the other hand, in the umbrella part of the engine valve, the columnar part of the metal base material is fitted into the space formed inside the frustoconical ceramic member in which the space is formed in the central axis part to constitute the umbrella part. An umbrella skirt is disposed at the lower part of the ceramic member. The ceramic member and the umbrella skirt are bonded and integrated through a glass coat layer.
In the engine valve configured as described above, a portion other than the umbrella hem portion (the surface of the umbrella hem portion of the metal base) on the back surface of the umbrella, which is the side surface of the umbrella portion, is formed of a ceramic member.

As described above, in the engine valve, since the entire surface of the glass coat layer is covered with the ceramic member, the glass constituting the umbrella portion of the engine valve is formed even after a sintering process for forming the glass coat layer at the time of manufacture. No shrinkage occurs at the edge of the coat layer. This is because the ceramic member does not easily shrink even after the sintering process, and the weight of the ceramic member inhibits the shrinkage of the glass coat layer. For this reason, the problem that the thickness of the glass coat layer constituting the umbrella portion of the engine valve is reduced at the end portion does not occur, and a sufficiently thick glass coat layer is formed even in the portion adjacent to the umbrella hem portion of the engine valve. can do. As a result, the engine valve can exhibit high heat insulation performance.

In the engine valve, when the glass coat layer is formed by sintering, strong adhesion is developed between the umbrella skirt of the metal substrate and the glass coat layer and between the glass coat layer and the ceramic member. To do. For this reason, even in a harsh environment where the engine valve is used, the glass coat layer formed on the umbrella part of the engine valve is difficult to peel off from the umbrella hem part of the metal base material, and high heat insulation performance can be exhibited.

The shape and structure of the engine valve according to the first aspect of the present invention will be further described in detail.
Fig.1 (a) is a perspective view which shows an example of the shaft united engine valve of this invention, FIG.1 (b) is A- of the shaft united engine valve shown to Fig.1 (a). It is A sectional view.

As shown in FIGS. 1A and 1B, an engine valve 10 which is an example of the engine valve of the first aspect of the present invention includes a rod-shaped shaft portion 11, a conical umbrella portion 12, and an umbrella portion 12. The metal base 20 that constitutes the engine valve 10 is composed of a shaft portion 21 and a base portion 22, and the base portion 22 is formed in a columnar column shape. It consists of a portion 22a and a disk-shaped umbrella skirt portion 22b. Further, regarding the shaft portion 11 and the umbrella skirt portion 13 of the engine valve 10, the shaft portion 21 and the umbrella skirt portion 22 b of the metal base material 20 are used as the shaft portion 11 and the umbrella skirt portion 13 as they are.

On the other hand, in the umbrella part 12 of the engine valve 10, the columnar part 22 a of the metal base material 20 is fitted into a space formed inside the frustoconical ceramic member 15 having a space formed in the central axis part. The umbrella part 12 is comprised and the umbrella skirt part 13 is arrange | positioned in the lower part of the ceramic member 15. FIG. The ceramic member 15 and the umbrella skirt 13 (umbrella skirt 22b) are bonded and integrated through the glass coat layer 16.
In the engine valve 10 configured as described above, a portion other than the umbrella hem portion (the surface of the umbrella hem portion 13) on the back surface of the umbrella that is the side surface of the umbrella portion 12 is configured by the ceramic member 15.

As described above, in the engine valve 10 shown in FIGS. 1A and 1B, the ceramic member 15 covers the entire surface of the glass coat layer 16, so that the firing for forming the glass coat layer 16 during manufacturing is performed. Even after the ligation process, the end portion of the glass coat layer 16 constituting the umbrella portion 12 of the engine valve 10 does not shrink. This is because the ceramic member 15 is unlikely to shrink even after the sintering process, and the weight of the ceramic member 15 inhibits the shrinkage of the glass coat layer 16. For this reason, the problem that the thickness of the glass coat layer 16 constituting the umbrella portion 12 of the engine valve 10 is reduced at the end portion does not occur, and the portion adjacent to the umbrella skirt portion 13 of the engine valve 10 has a sufficient thickness. A glass coat layer 16 can be formed. As a result, the engine valve can exhibit high heat insulation performance.

Further, in the engine valve 10 shown in FIGS. 1A and 1B, when the glass coat layer 16 is formed by sintering, the space between the umbrella skirt 22b of the metal base material 20 and the glass coat layer 16 is used. In addition, a strong adhesion force is developed between the glass coat layer 16 and the ceramic member 15. For this reason, even in a harsh environment where the engine valve 10 is used, the glass coat layer 16 formed on the umbrella portion 12 of the engine valve 10 is difficult to peel off from the umbrella skirt portion 22b of the metal base material 20, and high thermal insulation performance is achieved. It can be demonstrated.

As an example of the engine valve of the second aspect of the present invention, the following configuration can be cited.
The umbrella-unit engine valve of the present invention comprises a rod-shaped shaft portion, a cone-shaped umbrella portion, and an umbrella hem portion that is an umbrella hem portion of the umbrella portion, while the metal base constituting the engine valve The material includes a shaft portion and a base portion, and the base portion further includes a truncated cone-shaped truncated cone portion and an umbrella skirt portion. In addition, the truncated cone part and the umbrella skirt part are integrally formed. Further, regarding the shaft portion and the umbrella skirt portion of the engine valve, the shaft portion and the umbrella skirt portion of the metal substrate are used as they are as the shaft portion and the umbrella skirt portion.

On the other hand, in the umbrella portion of the engine valve, a truncated cone portion of a metal base material is fitted into a space formed inside the skirt-shaped ceramic member to constitute the umbrella portion, and at the lower portion of the umbrella portion The umbrella hem is arranged. Moreover, the ceramic member and the truncated cone part are bonded and integrated through a glass coat layer.
In the engine valve configured as described above, a portion other than the umbrella skirt (the surface of the umbrella skirt) on the back surface of the umbrella, which is the side surface of the umbrella, is formed of a ceramic member.

As described above, in the engine valve, since the entire surface of the glass coat layer is covered with the ceramic member, the glass constituting the umbrella portion of the engine valve is formed even after a sintering process for forming the glass coat layer at the time of manufacture. No shrinkage occurs at the edge of the coat layer. This is because the ceramic member does not easily shrink even after the sintering process, and the weight of the ceramic member inhibits the shrinkage of the glass coat layer. For this reason, the problem that the thickness of the glass coat layer constituting the umbrella portion of the engine valve is reduced at the end portion does not occur, and a sufficiently thick glass coat layer is formed even in the portion adjacent to the umbrella hem portion of the engine valve. can do. As a result, the engine valve can exhibit high heat insulation performance.

In the engine valve, when the glass coat layer is formed by sintering, strong adhesion is developed between the truncated cone portion of the metal base and the glass coat layer and between the glass coat layer and the ceramic member. To do. For this reason, even in a harsh environment where the engine valve is used, the glass coat layer formed on the umbrella part of the engine valve is difficult to peel off from the truncated cone part of the metal substrate, and high heat insulation performance can be exhibited.

The shape and structure of the engine valve according to the second aspect of the present invention will be further described in detail.
FIG. 2A is a perspective view showing an example of the umbrella-combined engine valve of the present invention, and FIG. 2B is a B- of the umbrella-combined engine valve shown in FIG. It is B line sectional drawing.

As shown in FIGS. 2A and 2B, an engine valve 30 which is an example of the engine valve of the present invention includes a rod-shaped shaft portion 31, a cone-shaped umbrella portion 32, and an umbrella hem among the umbrella portions 32. On the other hand, the metal base 40 constituting the engine valve 30 is composed of a shaft portion 41 and a base portion 42, and the base portion 42 is a truncated cone-shaped truncated cone portion. 42a and an umbrella skirt 42b. The truncated cone part 42a and the umbrella skirt part 42b are integrally formed. Further, with respect to the shaft portion 31 and the umbrella skirt portion 33 of the engine valve 30, the shaft portion 41 and the umbrella skirt portion 42 b of the metal base material 40 are used as the shaft portion 31 and the umbrella skirt portion 33 as they are.

On the other hand, in the umbrella part 32 of the engine valve 30, the truncated cone part 42a of the metal base material 40 is fitted into the space formed inside the skirt-shaped ceramic member 35 to constitute the umbrella part 32. An umbrella skirt 33 (42b) is disposed below the umbrella 32. Further, the ceramic member 35 and the truncated cone part 42a are bonded and integrated through the glass coat layer 36.
In the engine valve 30 configured as described above, a portion other than the umbrella hem portion (the surface of the umbrella hem portion 33) on the back surface of the umbrella that is the side surface of the umbrella portion 32 is configured by the ceramic member 35.

As described above, in the engine valve 30 shown in FIGS. 2A and 2B, the ceramic member 35 covers the entire surface of the glass coat layer 36, so that the firing for forming the glass coat layer 36 at the time of manufacture is performed. Even after the ligation process, the end portion of the glass coat layer 36 constituting the umbrella portion 32 of the engine valve 30 does not shrink. This is because the ceramic member 35 is unlikely to shrink even after the sintering process, and the weight of the ceramic member 35 inhibits the shrinkage of the glass coat layer 36. For this reason, the problem that the thickness of the glass coat layer 36 constituting the umbrella portion 32 of the engine valve 30 becomes thin at the end portion does not occur, and the portion adjacent to the umbrella skirt portion 33 of the engine valve 30 has a sufficient thickness. A glass coat layer 36 can be formed. As a result, the engine valve can exhibit high heat insulation performance.

Further, in the engine valve 30 shown in FIGS. 2A and 2B, when the glass coat layer 36 is formed by sintering, the gap between the truncated cone portion 42a of the metal substrate 40 and the glass coat layer 36 is determined. In addition, a strong adhesion force is developed between the glass coat layer 36 and the ceramic member 35. For this reason, even in a harsh environment where the engine valve 30 is used, the glass coat layer 36 formed on the umbrella portion 32 of the engine valve 30 is difficult to peel off from the truncated cone portion 42a of the metal substrate 40, and high heat insulation performance is achieved. It can be demonstrated.

Although the material of the metal base material which comprises the engine valve of this invention is not specifically limited, The metal conventionally used for the engine valve can be applied.
For example, stainless steel, heat resistant steel, aluminum, aluminum alloy, iron, inconel, hastelloy, invar, and the like can be given. Moreover, various cast products (for example, cast iron, cast steel, carbon steel, etc.) etc. are mentioned.
An example of the material of the engine valve (back surface of the umbrella of the engine valve) is heat resistant steel (SUH). Specifically, martensitic heat resistant steel (SUH3, SUH11, etc.), austenitic heat resistant steel (SUH35, etc.), ferritic heat resistant steel (SUH446, etc.) and the like can be mentioned. Further, Ni-based heat-resistant alloys such as Inconel (NCF751 etc.) are also included.

In addition, in the engine valve of the present invention, in order to improve the adhesion between the metal substrate and the glass coat layer, sandblasting or roughening treatment with a chemical is applied to the umbrella skirt portion or the truncated cone portion of the metal substrate. May be.

In the engine valve of the present invention, the surface roughness Rz _JIS of the umbrella skirt portion or the truncated cone portion of the metal base formed by the roughening treatment is preferably 0.3 to 20 μm. The surface roughness Rz _JIS described above is a ten-point average roughness defined by JIS B 0601 (2001).
When the surface roughness Rz _JIS of the umbrella base of the metal base is less than 0.3 μm, the surface area of the back of the umbrella of the metal base is reduced. It becomes difficult to obtain sufficient adhesion. On the other hand, when the surface roughness Rz _JIS of the umbrella base or the truncated cone part of the metal substrate exceeds 20 μm, it is difficult to form a glass coat layer on the umbrella base or the truncated cone part of the metal substrate. This is because when the surface roughness Rz _JIS of the umbrella base or truncated cone part of the metal base is too large, slurry (glass coating) is formed on the uneven valley formed on the umbrella base or truncated cone part of the metal base. This is probably because the composition for forming the layer does not enter, and voids are formed in this portion.
In addition, the surface roughness Rz _JIS of the umbrella base part or truncated cone part of a metal base material can be measured based on JIS B 0601 (2001) using Tokyo Seimitsu make and Handy Surf E-35B. The measurement is performed at 25 ° C. and atmospheric pressure.

In the engine valve of the present invention, the shape of the shaft portion constituting the engine valve is not particularly limited, but is preferably a cylindrical shape. Moreover, it is preferable that the shape of an umbrella part is a substantially cone shape.

In the engine valve of the present invention, the width of the engine valve umbrella bottom is preferably 3 to 20% of the width of the engine valve umbrella back in the direction from the umbrella back of the engine valve to the engine valve shaft. . Moreover, it is preferable that the area of the umbrella skirt part in the back of the umbrella is 5 to 50% of the area of the back of the umbrella.

The ceramic member constituting the engine valve of the present invention is preferably made of a ceramic raw material, and the ceramic raw material is preferably a crystalline inorganic material.
The crystalline inorganic material is preferably made of at least one selected from the group consisting of alumina, zirconia, yttria, calcia, magnesia, ceria, and hafnia. Of these, zirconia is more preferred.

In the engine valve of the present invention, the shape of the ceramic member is not particularly limited. However, like the ceramic member in the engine valve shown in FIGS. It may have a truncated cone shape in which a space for fitting the portions is formed, or may have a skirt shape like a ceramic member in the engine valve shown in FIGS. 2 (a) and 2 (b).

In the engine valve of the present invention, the ceramic member preferably has pores, and the porosity of the ceramic member is preferably 10 to 60%.
When the porosity of the ceramic member is less than 10%, it becomes difficult to follow the change in size due to the difference in the coefficient of thermal expansion from the metal base material, and it is easy to break due to the stress generated by the temperature change. If the porosity exceeds 60%, the mechanical strength decreases, and it tends to be broken by the stress generated by the temperature change.
When the ceramic member has pores, the heat insulating performance of the engine valve is further improved. Moreover, even if a stress due to a difference in thermal expansion occurs between the glass coat layer and the ceramic member in the sintering step when forming the glass coat layer, the stress is relieved by the pores. For this reason, even if the toughness of the glass coat layer is low, the ceramic member is more prevented from being damaged by absorbing stress during sintering. Further, the glass coat layer raw material diffuses into the pores in the sintering process and exhibits an anchor effect, whereby stronger adhesion between the glass coat layer and the ceramic member becomes possible.

Although the porosity of the ceramic member of the present invention is measured by the Archimedes method, specifically, it can be measured using the following method.
First, as a pretreatment, a sample to be subjected to porosity measurement is washed with ultrasonic waves using ion-exchanged water and acetone, and then dried at 100 ° C.
Next, the sample subjected to the pretreatment is boiled with ion-exchanged water for 3 hours to prepare a saturated sample. Subsequently, the saturated sample is hung with a thread in water, and the buoyancy (W1) of the saturated sample is measured with an electronic balance. Further, the mass (W2) of the saturated sample is measured with an electronic balance, dried at 120 ° C. for 60 minutes, and then the mass (W3) of the dried sample is measured.
Using the results obtained by the above method, the porosity is calculated by the following calculation formula.
{[Mass of saturated sample (W2) −mass of dry sample (W3)] / buoyancy of saturated sample (W1)} × 100 (%)

In the shaft-combined engine valve of the present invention, the size of the ceramic member is not particularly limited. However, when the total volume of the ceramic member and the space formed inside thereof is 100%, the size relative to the total volume is described above. The volume ratio of the ceramic member is preferably 50 to 90%.
In the shaft-combined engine valve of the present invention, when the ratio of the volume of the ceramic member to the total volume is 50 to 90%, the end portion on the shaft portion side of the umbrella hem portion of the umbrella portion of the engine valve The portion from the shaft portion of the engine valve to the shaft portion of the engine valve is mainly composed of a ceramic member, and the ceramic member is bonded and integrated with the umbrella skirt portion of the metal substrate through the glass coat layer. For this reason, the part from the edge part by the side of the shaft part of the umbrella bottom part of the umbrella part of an engine valve to the shaft part of an engine valve can exhibit higher heat insulation performance. Therefore, when the engine valve of the present invention has the above configuration, the above-described effects of the present invention can be more fully exhibited.

In the umbrella part-combined engine valve of the present invention, the size of the ceramic member is not particularly limited, but when the total volume of the ceramic member and the space formed therein is 100%, the above-mentioned total volume The volume ratio of the ceramic member is preferably 50 to 90%.
In the umbrella part-combined engine valve, when the ratio of the volume of the ceramic member to the total volume is 50 to 90%, from the end part on the shaft part side of the umbrella skirt part to the shaft part of the engine valve, The back of the umbrella of the engine valve can exhibit higher heat insulation performance. Therefore, when the engine valve of the present invention has the above configuration, the above-described effects of the present invention can be more fully exhibited.

The glass coat layer constituting the engine valve of the present invention is preferably composed of an amorphous inorganic material and a crystalline inorganic material.
In the engine valve of the present invention, the amorphous inorganic material is preferably made of glass, and more preferably low-softening point glass having a softening point of 300 to 1000 ° C.
Examples of the low softening point glass having a softening point of 300 to 1000 ° C. include SiO ₂ —B ₂ O ₃ —ZnO glass, SiO ₂ —B ₂ O ₃ —Bi ₂ O ₃ glass, and SiO ₂ —PbO glass. SiO ₂ —PbO—B ₂ O ₃ glass, SiO ₂ —B ₂ O ₃ —PbO glass, B ₂ O ₃ —ZnO—PbO glass, B ₂ O ₃ —ZnO—Bi ₂ O ₃ glass, B ₂ O ₃ -Bi ₂ O ₃ based _glass, B ₂ O 3 -ZnO based glass, BaO-SiO ₂ based _glass, SiO ₂ -B ₂ O 3 -RO based _{glass, SiO 2 -B 2 O 3 -R} 2 O-type glass (R is a transition metal) etc. are mentioned.
The softening point is measured using, for example, a glass automatic softening point / strain point measuring device (SSPM-31) manufactured by Opto Corporation, based on the method defined in JIS R 3103-1: 2001. Can do. The measurement is performed at atmospheric pressure.

In the engine valve of the present invention, the crystalline inorganic material is preferably made of at least one selected from the group consisting of alumina, zirconia, yttria, calcia, magnesia, ceria, and hafnia.
The crystalline inorganic material is also preferably an oxide of at least one metal selected from manganese, iron, cobalt, copper, chromium, and nickel.

In the engine valve of the present invention, the content of the crystalline inorganic material contained in the glass coat layer is desirably 1 to 50% by weight, and preferably 10 to 45% by weight, based on the weight of the glass coat layer. Is more desirable.

In the engine valve of the present invention, the glass coat layer preferably has a thickness of 10 to 500 μm.
For the measurement of the thickness of the glass coat layer, a dual scope MP40 manufactured by Fisher Instruments Inc. can be used. After performing film thickness correction in the film thickness measurement of the dual scope MP40 at any 30 points on the ceramic coat layer, the film thickness measurement is performed on any 10 points on the glass coat layer, and the measured values are averaged. Thus, the thickness of the glass coat layer can be measured. When film thickness measurement is performed with respect to 10 points, it is desirable to prevent the measurement site from being biased within the measurement region. For example, a method of performing measurement at regular intervals of 1 mm may be used.
When the thickness of the glass coat layer is within the above range, it is possible to prevent a decrease in intake efficiency without the heat of the in-valve being transmitted to the intake. Further, since the heat of the exhaust gas is not easily transmitted to the exhaust valve, and the temperature of the exhaust gas is less likely to decrease, the exhaust gas can be purified by sufficiently warming the carrier when the exhaust gas reaches the carrier. There exists a problem that the adhesive strength of a metal base material and a ceramic member will become it low that the thickness of a glass coat layer is less than 10 micrometers. On the other hand, if the thickness of the glass coat layer exceeds 500 μm, cracks may easily occur in the glass coat layer when a thermal shock or the like is applied to the glass coat layer. There is also a problem that the intake or exhaust path becomes narrow.

In the engine valve of the present invention, the glass coat layer preferably has pores. The average pore diameter of the pores formed in the glass coat layer is preferably 0.5 to 15 μm. The average pore diameter is more preferably 3 to 13 μm, still more preferably 5 to 10 μm.
When the average pore diameter of the pores is 0.5 to 15 μm, the pores are present as independent pores in the glass coat layer, and function effectively as a structure that enhances heat insulation.

In the engine valve of the present invention, the porosity of the glass coat layer is preferably 10 to 60%.
The porosity is more preferably 15 to 50%, still more preferably 20 to 40%. When the porosity is 10 to 60%, sufficient heat insulation by the pores is maintained.

In the engine valve of the present invention, the average pore diameter of the pores of the glass coat layer is measured by cutting a portion of the engine valve umbrella where the glass coat layer is formed and observing a cross section using an SEM or the like. Can do.
Specifically, the average pore diameter can be obtained by photographing the SEM image so that the entire area of the glass coat layer in the thickness direction is included, measuring the pore diameters of all the pores, and obtaining the average value. When the shape of the pores is not substantially spherical, the diameter of the pores is the diameter corresponding to the projected area circle (Haywood diameter).
The measurement magnification of SEM is 500 times when the thickness of the glass coat layer is less than 220 to 300 μm, 200 times when the thickness is less than 300 to 500 μm, and 150 times when the thickness is 500 to 1000 μm.
The porosity of the glass coat layer is calculated from the weight of the glass coat layer and the thickness of the glass coat layer measured with a film thickness meter (dual scope), and the ratio of the true density calculated with a pycnometer is calculated. Then, the value obtained by subtracting the value from 1 can be calculated as the porosity.

The engine valve of the present invention is used for an engine.
Here, an example of the structure of the engine in which the engine valve of the present invention is used will be described.

In an engine combustion chamber of an engine in which the engine valve of the present invention is used, an intake engine valve (in-valve) and an exhaust engine valve (ex-valve) are arranged above the cylindrical cylinder. A spark plug is provided at the top of the cylinder, and a piston is provided inside the cylinder.
The engine valve of the present invention is most suitable for the engine combustion chamber having such a configuration.
The back surface of the umbrella of the engine valve is a side surface of the umbrella portion of the engine valve, and means a surface that does not face the engine combustion chamber in the umbrella portion of the engine valve. Moreover, the umbrella skirt part of the umbrella back surface in which the glass coat layer is not formed is a part which contacts a cylinder.

Although the engine valve for intake and the engine valve for exhaust have the same configuration, in the following description, when it is necessary to distinguish between the two, the engine valve for intake is referred to as an in-valve, and the engine valve for exhaust is used. Is described as an exhaust valve, and when it is not necessary to distinguish between the two, it is simply described as an engine valve.

Since a ceramic member exists on the back of the umbrella of the in-valve and the exhaust valve, the heat insulation is high. Therefore, the following effects are exhibited.
Since the in-valve is highly heat-insulating, the heat of the in-valve is not easily transmitted to the intake air. Therefore, the engine can be driven without reducing the intake efficiency.
Moreover, since the exhaust valve has high heat insulating properties, the heat of the exhaust gas is difficult to be transmitted to the exhaust valve. Therefore, the temperature of the exhaust gas is unlikely to decrease. The exhaust gas is purified by the carrier installed in the exhaust gas purification device installed downstream of the engine. If the temperature of the exhaust gas is not lowered, the exhaust gas quickly raises the temperature of the carrier, The exhaust gas purification function can be suitably exhibited. That is, exhaust gas purification efficiency is improved.

Further, when the engine is driven, fuel is sucked and exhaust gas is discharged. At this time, the engine valve repeatedly contacts the cylinder.
In the engine valve of the present invention, when the glass coat layer is formed by sintering, a strong adhesive force is developed between the metal substrate and the glass coat layer and between the glass coat layer and the ceramic member. For this reason, even in a harsh environment where the engine valve is used, the ceramic member formed on the back surface of the umbrella of the engine valve is difficult to peel off from the metal base material, and high heat insulation performance can be exhibited.

The engine in which the engine valve of the present invention is used will be further described in detail.
FIG. 3 is a cross-sectional view schematically showing an example of the structure of an engine combustion chamber in which the engine valve of the present invention is used.

As shown in FIG. 3, in the engine combustion chamber 150, an intake engine valve 160 (in-valve 160 a) and an exhaust engine valve 160 (exhaust valve 160 b) are disposed above a cylindrical cylinder 170. A spark plug 180 is provided at the top of the cylinder 170, and a piston 190 is provided inside the cylinder 170.
The engine valve of the present invention is most suitable for the engine combustion chamber having such a configuration.
The umbrella back surfaces 166 a and 166 b of the engine valve 160 are side surfaces of the umbrella portion 166 of the engine valve 160, and mean surfaces of the umbrella portion 166 of the engine valve 160 that do not face the engine combustion chamber 150. . Moreover, the umbrella skirt part 1660 on the back surface of the umbrella where the glass coat layer is not formed is a part in contact with the cylinder 170. In addition, about the position of a ceramic member, a glass coat layer, etc., since it has shown with the engine valve shown in FIGS. 1-2, it does not show in figure here.

Although the intake engine valve 160 and the exhaust engine valve 160 have the same configuration, in the following description, when it is necessary to distinguish between the two, the intake engine valve 160 is referred to as an in-valve 160a, and the exhaust The engine valve 160 for use is described as an exhaust valve 160b, and when it is not necessary to distinguish between the two, it is simply described as the engine valve 160.

Since a ceramic member exists on the back of the umbrella of the in-valve 160a and the exhaust valve 160b, the heat insulation is high. Therefore, the following effects are exhibited.
Since the in-valve 160a has a high heat insulating property, the heat of the in-valve 160a is difficult to be transmitted to the intake air. Therefore, the engine can be driven without reducing the intake efficiency.
Further, since the exhaust valve 160b has high heat insulating properties, the heat of exhaust gas is difficult to be transmitted to the exhaust valve 160b. Therefore, the temperature of the exhaust gas is unlikely to decrease. The exhaust gas is purified by the carrier installed in the exhaust gas purification device installed downstream of the engine. If the temperature of the exhaust gas is not lowered, the exhaust gas quickly raises the temperature of the carrier, The exhaust gas purification function can be suitably exhibited. That is, exhaust gas purification efficiency is improved.

Further, when the engine is driven, fuel is sucked and exhaust gas is discharged. At this time, the engine valve 160 repeatedly comes into contact with the cylinder 170.
In the engine valve of the present invention, when the glass coat layer is formed by sintering, a strong adhesive force is developed between the metal substrate and the glass coat layer and between the glass coat layer and the ceramic member. For this reason, even in a harsh environment where the engine valve is used, the ceramic member formed on the back surface of the umbrella of the engine valve is difficult to peel off from the metal base material, and high heat insulation performance can be exhibited.

Next, a method for manufacturing the engine valve of the present invention will be described.
A method for manufacturing an engine valve according to a first aspect of the present invention includes: a glass paste layer forming step of forming a glass paste layer by applying a glass paste to an umbrella skirt constituting the base portion of the metal base; A ceramic member disposing step of disposing the ceramic member on the surface of the glass paste layer and sintering the glass paste layer while fitting the columnar portion constituting the metal base material into the formed space. Thus, the method includes forming a glass coat layer and bonding the ceramic member and the umbrella skirt portion of the metal base material via the glass coat layer.

The engine valve manufacturing method according to the second aspect of the present invention includes a glass paste layer forming step of forming a glass paste layer by applying a glass paste to the surface of the base portion of the metal base, and a space formed inside the ceramic member. The glass base layer is inserted into the base of the metal base, and the ceramic member is disposed on the surface of the glass paste layer, and the glass paste layer is sintered to sinter the glass coat layer. And forming an adhesion step of bonding the ceramic member and the base portion of the metal substrate through the glass coat layer.

Since the manufacturing method of the engine valve according to the first aspect of the present invention and the manufacturing method of the engine valve according to the second aspect of the present invention are basically the same method, hereinafter, as the manufacturing method of the engine valve of the present invention, Both inventions will be described in parallel. However, when necessary, the method for manufacturing the shaft-unit-combined engine valve and the method for manufacturing the umbrella-unit-combined engine valve will be described separately.

(A) Preparation of metal substrate In the method for manufacturing an engine valve of the present invention, first, a metal substrate constituting the engine valve is prepared.

Since the shape, material, and the like of the metal base are the same as those described in the description of the engine valve of the present invention, the description thereof is omitted here.

In preparing the metal base material, it is preferable to perform a cleaning process to remove impurities at the umbrella skirt portion or the truncated cone portion, which is the surface on which the glass coat layer is formed.
The cleaning treatment is not particularly limited, and a conventionally known cleaning treatment method can be used. Specifically, for example, a method of performing ultrasonic cleaning in an alcohol solvent can be used.

In the method for manufacturing an engine valve of the present invention, when it is desired to further improve the adhesion between the umbrella base or the truncated cone part of the metal substrate and the glass coat layer, a roughening treatment is applied to the umbrella base or the truncated cone part. You may give it. Examples of the roughening treatment include sand blast treatment, etching treatment, and high temperature oxidation treatment. These may be used alone or in combination of two or more. You may perform a washing process after this roughening process.
In addition, it is preferable to perform a roughening process before the glass paste layer formation process which forms the glass paste layer mentioned later.

(B) Glass paste layer formation process (b-1) Glass paste preparation process In the engine valve manufacturing method of the present invention, subsequently, a glass paste for forming a glass paste layer is prepared.
The glass paste is obtained by mixing glass raw materials. When carbon particles for forming pores are added to the glass paste, the glass raw material and carbon particles are mixed.

Since the glass raw material and the carbon particles are the same as those described in the description of the engine valve of the present invention, the description thereof is omitted here.

The raw material mixture can be obtained, for example, by mixing a glass raw material, water, and optionally added carbon particles, and wet-mixing them with a ball mill or the like. The order and combination of mixing the three components are not particularly limited. For example, the glass raw material and water may be mixed first, and then carbon particles may be added, or water may be added after mixing the glass raw material and carbon particles. Alternatively, the glass raw material, carbon particles, and water may be mixed at a time.

When the glass paste contains carbon particles, the carbon particles burn in the subsequent firing step to generate CO and CO ₂ to form pores. That is, the carbon particles function as a pore forming agent.
Moreover, it is preferable that a part of carbon particle remains in a glass coat layer after a baking process.

The compounding ratio of the glass raw material and water is not particularly limited, but is preferably about 100 parts by weight of water with respect to 100 parts by weight of the glass raw material. This is because, when the glass raw material and water are mixed at such a weight ratio, the viscosity is suitable for application to the back of the engine valve umbrella. Moreover, you may mix | blend dispersion media, such as an organic solvent, and an organic binder with the said glass paste as needed.

As the dispersion medium, for example, water or an organic solvent such as methanol or ethanol can be used. Although content of the dispersion medium in a glass paste is not specifically limited, For example, it is preferable that a dispersion medium is 50-150 weight part with respect to 100 weight part of glass raw materials. This is because, by blending the dispersion medium at such a ratio, the viscosity of the glass paste becomes a viscosity suitable for application to the back of the umbrella of the metal substrate.
Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and the like. These may be used alone or in combination of two or more. Further, a dispersion medium and an organic binder may be used in combination.

The content of carbon particles in the glass paste is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the glass raw material.
The content of carbon particles is more preferably 0.005 to 8 parts by weight, and further preferably 0.008 to 5 parts by weight.
By setting the content of the carbon particles in such a range, a large number of pores are formed, so that a glass coat layer having a desired porosity and a desired heat insulation performance can be formed without growing the pores so much.
Since the pores do not grow so much, each individual pore becomes smaller, and since it is not necessary to take a long heating time for growing the pores, the degree of pore formation is uniform, and the glass coat has a sharp pore size distribution A layer can be formed.
In addition, when a large amount of carbon particles is blended, carbon particles that have not been gasified tend to remain in the glass coat layer.

A crystalline inorganic material may be further added to the glass paste as necessary.
When the crystalline inorganic material is added to the glass paste, the timing of adding the crystalline inorganic material is not particularly limited. For example, before mixing the glass raw material, water, and optionally added carbon particles, the glass raw material is mixed. And a step of mixing the crystalline inorganic material.
Since the crystalline inorganic material is the same as that described in the description of the engine valve of the present invention, the description thereof is omitted here.
In addition, when adding a crystalline inorganic material as a glass paste, it has the process of mixing a glass raw material and a crystalline inorganic material before mixing the glass raw material mentioned above, water, and the carbon particle added as needed. May be.

(B-2) Application process In the manufacturing method of the engine valve of the present invention, next, as an application process, a glass paste for forming a glass paste layer is applied to an umbrella skirt or a truncated cone part of a metal substrate. By doing so, a glass paste layer is formed.

Although the thickness of a glass paste layer is not specifically limited, It is preferable that it is the thickness of 10-500 micrometers, and it is preferable that it is the thickness which can form the glass coat layer of the thickness of 20-300 micrometers.
There exists a problem that the adhesive strength of a metal base material and a ceramic member will become it low that the thickness of a glass paste layer is less than 10 micrometers. On the other hand, if the thickness of the formed glass coat layer exceeds 500 μm, cracks may easily occur when a thermal shock or the like is applied to the glass coat layer. There is also a problem that the intake or exhaust path becomes narrow.

Examples of a method for forming a glass paste layer on an umbrella skirt or truncated cone portion of a metal base include, for example, spray coating, electrostatic coating, ink jet, spin coating, transfer using a stamp or roller, brush coating, and the like. Is mentioned. When the glass paste layer is formed by spray coating or the like, the portion other than the glass paste layer is covered with a tape or a resin, and after the glass paste layer is formed, the tape or the resin is removed to a predetermined area. A glass paste layer can be formed.

(C) Ceramic member arrangement process In the manufacturing method of the engine part shaft-type engine valve of the present invention, the glass paste that is fitted to the columnar part of the metal base material and is formed on the umbrella base part of the metal base material The ceramic member is placed in contact with the layer.
Moreover, in the manufacturing method of the engine part umbrella type | mold engine valve of this invention valve | bulb, a ceramic member is arrange | positioned so that the glass paste layer formed in the surface of the truncated cone part of a metal base material may be contacted.

(D) Adhesion process Next, in the method for manufacturing an engine valve of the present invention, the glass paste layer is sintered to form a glass coat layer, and the ceramic member and the metal substrate (umbrella skirt or cone) are formed. The base part) is bonded via a glass coat layer.
For example, when carbon particles are contained in the glass paste, the carbon particles can be vaporized in the glass paste layer by the sintering process, and pores can be formed in the glass coat layer.

The glass paste layer can be sintered by subjecting the engine valve on which the glass paste layer is formed to heat treatment. Moreover, in this invention, before performing sintering, you may perform the drying process for drying a glass paste layer with respect to the engine valve in which the glass paste layer was formed as needed. A drying process can be performed at the temperature of about 50-150 degreeC, for example.
The heat treatment conditions for sintering can be arbitrarily set in consideration of the material of the engine valve, etc., but when the material of the engine valve is stainless steel, it is 400 to 1100 ° C., when it is heat resistant steel Is preferably heat-treated at 400 to 1100 ° C. The heating time is preferably 3 to 120 minutes.
Moreover, it is preferable that the heat processing temperature for sintering shall be more than the softening point of a glass raw material. By setting the heating temperature to a temperature equal to or higher than the softening point of the glass raw material, the applied glass raw material is softened and melted, and the formed glass coat layer and the metal substrate engine valve umbrella back firmly adhere to each other.

At this time, the carbon particles contained in the glass paste are dispersed in the softened glass raw material, and pores are formed by causing thermal decomposition.
Further, when the pores are exposed on the surface of the glass coat layer during the sintering step, the glass raw material forming the glass coat layer is softened, so that the portion where the pores are exposed can be closed quickly. Therefore, the glass coating layer after baking does not have pores exposed on the surface, and a glass coating layer having high flatness (low surface roughness) can be obtained.

Below, the effect of the engine valve of this invention is enumerated.
(1) In the engine valve of the present invention, the back surface of the umbrella other than the umbrella skirt is made of the ceramic member, and between the ceramic member and a metal base material constituting the umbrella portion of the engine valve. Since the glass coat layer is formed, it is possible to improve the heat insulation of the portion from the shaft portion side end portion of the umbrella skirt portion on the back surface of the umbrella of the engine valve to the shaft portion of the engine valve.

(2) In the umbrella part of the engine valve of the present invention, the ceramic member is integrally bonded to the base part of the metal base material via a glass coat layer. For this reason, in the engine valve of the present invention, the ceramic member covers the entire surface of the glass coat layer. Thereby, even if it passes through the sintering process for forming a glass coat layer at the time of manufacture, the edge part of the glass coat layer which comprises the umbrella part of an engine valve does not generate | occur | produce. This is because the ceramic member does not easily shrink even after the sintering process, and the weight of the ceramic member inhibits the shrinkage of the glass coat layer. For this reason, the problem that the thickness of the glass coat layer constituting the umbrella part of the engine valve becomes thin at the end portion does not occur, and a glass coat layer having a sufficient thickness is also formed in the part adjacent to the umbrella hem part of the engine valve. Can be formed. As a result, the engine valve can exhibit high heat insulation performance.

(3) Furthermore, in the engine valve of the present invention, when the glass coat layer is formed by sintering, a strong adhesion is provided between the metal substrate and the glass coat layer and between the glass coat layer and the ceramic member. To express. For this reason, even in a harsh environment where the engine valve is used, the glass coat layer formed on the umbrella portion of the engine valve is difficult to peel off from the metal base material, and high heat insulation performance can be exhibited.

(Example)
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
Example 1
(A) Engine valve base material preparation step First, the base part is composed of a base part and a shaft part, and the base part is composed of a columnar part and an umbrella skirt part shown in FIGS. 1 (a) and 1 (b). Prepared. The constituent material of the metal substrate was stainless steel (SUS430).
The shape of the shaft portion of the metal substrate was a rod shape having a diameter of 5.5 mm and a total length of 105.5 mm.
The shape of the base portion of the metal substrate is a rod shape with a columnar shape of 5.5 mm in diameter and 10.5 mm in length, and the shape of the umbrella skirt is a circle with a bottom of 28 mm in diameter, and its thickness is It was a 3 mm disk shape.

FIG. 4A is a perspective view illustrating the shape of the ceramic member according to the first embodiment, in which the upper surface diameter is d ₁ , the bottom surface diameter is d ₂ , and the height is h ₁ .
Ceramic member is a truncated cone shape, as shown in FIG. 4 (a), the diameter _{d 1} to the central axis portion are formed hollow cylindrical shape of 6.05 mm, the diameter _{d 2} of the bottom 25 mm, the top diameter It was a zirconia sintered body having a d ₁ of 6.05 mm and a height h ₁ of 6.5 mm. Moreover, it was 16% when the porosity of the ceramic member which consists of a zirconia sintered compact was measured by the above-mentioned Archimedes method.

(B) Coating layer forming step (b-1) Raw material mixture preparing step Next, 100 parts by weight of barium silicate glass (softening point 770 ° C.) as a ceramic raw material, 100 parts by weight of water, and 1 part by weight of methyl cellulose as an organic binder A raw material mixture was prepared by wet-mixing 0.23 parts by weight of graphitized carbon particles as a pore former with a ball mill or the like.

(B-2) Coating process Next, the coating layer for forming the glass coat layer was formed by coating the raw material mixture on the entire surface of the metal base for engine valve that opposes the umbrella surface of the umbrella base. . The thickness of the coating layer was 50 μm.
Subsequently, a ceramic member made of a zirconia sintered body was fitted so as to be fitted to the columnar portion of the metal substrate.

(C) Heat treatment step Next, the substrate was dried in a dryer at 70 ° C. for 20 minutes.
Furthermore, a glass coat layer having a thickness of 40 μm is formed by heat treatment at 800 ° C. for 90 minutes in a firing furnace in the air, and the ceramic member and the umbrella skirt are bonded with the glass coat layer. Finished manufacturing.
The produced glass coat layer had pores, the porosity was 25%, and the average pore diameter was 4 μm. The thickness of the glass coat layer is determined with a film thickness meter (dual scope), and the average pore diameter is obtained using a photograph obtained by photographing the glass coat layer with an SEM after cutting the umbrella part of the engine valve. Were determined.
The porosity of the glass coat layer is calculated from the weight of the glass coat layer and the thickness of the glass coat layer measured with a film thickness meter (dual scope), and the ratio of the true density calculated with a pycnometer is calculated. Then, the value was subtracted from 1, and the value as a percentage was calculated as the porosity.
As a specific method of calculating the true density with a pycnometer, the glass coat layer is made into a powder form and measured with a continuous automatic powder true density measuring instrument [Autotrudenser MAT-7000, manufactured by Seishin Enterprise Co., Ltd.]. The measurement solvent is not particularly limited as long as it does not react with the diffusion member to be measured. In Example 1, n-butanol was used.

(Example 2)
(A) Engine valve base material preparation step It consists of a base part and a shaft part, and the base part prepared a metal base material for an engine valve consisting of a truncated cone part and an umbrella skirt part. The constituent material of the metal substrate was stainless steel (SUS430).
The shape of the shaft portion of the metal substrate is the same as in the case of Example 1, and the shape of the base portion of the metal substrate is a truncated cone shape in which the truncated cone portion and the umbrella skirt portion are integrated, and the bottom surface The diameter of this was a truncated cone shape with a diameter of 28 mm and a height of 13.5 mm.

FIG. 4B is a perspective view illustrating the shape of the skirt-shaped ceramic member according to the second embodiment, in which the upper surface diameter is d ₃ , the bottom surface diameter is d ₄ , and the height is h ₂ .
As shown in FIG. 4B, the ceramic member has a skirt shape, and a through-hole having a diameter d ₃ = 6.05 mm is formed in the central axis portion. The thickness d _{5 is} 2 mm, and the bottom diameter d _{4 is 4} mm. A zirconia sintered body having a height of 25 mm and a height h _{2 of} 6.5 mm. Moreover, it was 16% when the porosity of the ceramic member which consists of a zirconia sintered compact was measured by the above-mentioned Archimedes method.

(B) Coating layer forming step (b-1) Raw material mixture preparation step A raw material mixture was prepared in the same manner as in Example 1.

(B-2) Application | coating process Next, the coating layer for glass-coat layer formation was formed by apply | coating a raw material mixture to the whole surface of the truncated cone part of the metal base material for engine valves. The thickness of the coating layer was 50 μm.
Then, the ceramic member which consists of a zirconia sintered compact was inserted so that the coating layer for glass coating layer formation of the truncated cone part of a metal base material might be contacted.

(C) Heat treatment step Next, the substrate was dried in a dryer at 70 ° C. for 20 minutes.
Furthermore, a glass coat layer having a thickness of 40 μm is formed by heat treatment at 800 ° C. for 90 minutes in a firing furnace in the air, and the frustum portion and the ceramic member are bonded together by the glass coat layer. Finished manufacturing.
The produced glass coat layer had pores, the porosity was 25%, and the average pore diameter was 4 μm. The thickness of the glass coat layer was determined with a film thickness meter (dual scope), and the average pore diameter was determined using a photograph obtained by photographing the glass coat layer with SEM.
The porosity of the glass coat layer is the same as in Example 1 except that the bulk density is calculated from the weight of the glass coat layer and the thickness of the glass coat layer measured with a film thickness meter (dual scope), and the true value calculated with a pycnometer is used. The ratio with the density was calculated, the value was subtracted from 1, and the percentage value was calculated as the porosity.

(Evaluation of glass coat layer)
The manufactured engine valve according to Example 1 and the engine valve according to Example 2 were cut parallel to the shaft portion at a portion close to the shaft portion, and the thickness of the glass coat layer in the cross section was observed with a microscope. As a result, in the engine valve according to Example 1 and Example 2, the glass coat layer was not contracted, and the glass coat layer had a substantially uniform thickness.

10, 30 Engine valve 11, 31 Shaft (engine valve)
12, 32 Umbrella part (engine valve)
13, 33 Umbrella hem (engine valve)
15, 35 Ceramic member 16, 36 Glass coat layer 20, 40 Metal substrate 21, 41 Shaft (metal substrate)
22, 42 Base part (metal substrate)
22a Columnar part (metal substrate)
22b Umbrella hem (metal base)
42a truncated cone part 42b umbrella skirt part 150 engine combustion chamber 160 (160a) engine valve (in-valve)
160 (160b) Engine valve (exhaust valve)
170 Cylinder 180 Spark plug 166 (166a) Engine valve (in-valve) umbrella back surface 166 (166b) Engine valve (ex-valve) umbrella back surface 190 Piston 1660

Claims (19)

An engine valve composed of a metal base composed of a shaft and a base, and a ceramic member,
The base part is composed of a columnar part and an umbrella skirt part,
Portions other than the umbrella hem portion on the back of the umbrella of the engine valve are made of the ceramic member,
The columnar part is combined in a space formed inside the ceramic member to constitute an umbrella part of the engine valve;
The engine valve is characterized in that the ceramic member is bonded to and integrated with an umbrella skirt portion of the metal substrate through a glass coat layer. 2. The engine valve according to claim 1, wherein a ratio of the volume of the ceramic member to the total volume is 50 to 90% when a total volume of the ceramic member and a space formed therein is 100%. The engine valve according to claim 2, wherein a ratio of the volume of the ceramic member to the total volume is 80 to 90% when a total volume of the ceramic member and a space formed therein is 100%. An engine valve composed of a metal base composed of a shaft and a truncated cone-shaped base, and a ceramic member,
Portions other than the umbrella hem portion on the back of the umbrella of the engine valve are made of the ceramic member,
A part of the base part is combined in a space formed inside the ceramic member to constitute an umbrella part of the engine valve,
The engine valve, wherein the ceramic member is bonded to and integrated with a base portion of the metal base material through a glass coat layer. 5. The engine valve according to claim 4, wherein a ratio of the volume of the ceramic member to the total volume is 50 to 90% when a total volume of the ceramic member and a space formed therein is 100%. The engine valve according to claim 5, wherein a ratio of the volume of the ceramic member to the total volume is 70 to 80% when a total volume of the ceramic member and a space formed therein is 100%. The engine valve according to claim 1, wherein the ceramic member has pores. The engine valve according to claim 7, wherein a component of the glass coat layer penetrates into the pores of the ceramic member. The engine valve according to claim 1, wherein the glass coat layer has pores. The engine valve according to claim 1, wherein the glass coat layer has a thickness of 10 to 500 μm. The width of the umbrella hem portion is 3 to 20% of the width of the back surface of the umbrella of the engine valve in a direction from the umbrella skirt of the umbrella back surface of the engine valve toward the shaft portion of the engine valve. The engine valve described in Crab. The engine valve according to claim 1, wherein the glass coat layer includes an amorphous inorganic material. The engine valve according to claim 12, wherein the glass coat layer includes a crystalline inorganic material. The engine valve according to claim 12 or 13, wherein the amorphous inorganic material is a low softening point glass having a softening point of 300 to 1000 ° C. The engine valve according to claim 13, wherein the crystalline inorganic material is at least one selected from the group consisting of alumina, zirconia, yttria, calcia, magnesia, ceria and hafnia. The engine valve according to claim 1, wherein the ceramic member is made of zirconia. It is a manufacturing method of the engine valve in any one of Claims 1-3 and 7-16,
A glass paste layer forming step of forming a glass paste layer by applying a glass paste to an umbrella skirt constituting the base portion of the metal substrate;
A ceramic member arranging step of fitting the columnar portion constituting the metal base material into a space formed inside the ceramic member, and arranging the ceramic member on the surface of the glass paste layer, and
A step of forming a glass coat layer by sintering the glass paste layer, and an adhesion step of bonding the ceramic member and an umbrella skirt portion of the metal base material via the glass coat layer; A method for manufacturing an engine valve. A method for manufacturing an engine valve according to any one of claims 4 to 16,
A glass paste layer forming step of forming a glass paste layer by applying a glass paste to the surface of the base portion of the metal substrate;
A ceramic member arranging step of fitting the base portion of the metal base material into a space formed inside the ceramic member, and arranging the ceramic member on the surface of the glass paste layer, and
The glass paste layer is formed by sintering the glass paste layer, and includes an adhesion step of bonding the ceramic member and the base portion of the metal substrate through the glass coat layer. A method for manufacturing an engine valve. A ceramic member used for an engine valve,
The said engine valve is an engine valve of Claims 1-16, The ceramic member characterized by the above-mentioned.

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