JPH07223B2 - Manufacturing method of ceramics cast-in member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cast iron cylinder head, a cast iron piston,
The present invention relates to a method for manufacturing a ceramics cast-in member manufactured by casting when manufacturing a cast iron component such as a cast iron exhaust manifold that is repeatedly subjected to high thermal stress.

[Conventional technology]

The cylinder head and the cylinder liner forming the combustion chamber of the internal combustion engine are usually made of cast iron. For this reason,
In addition to the properties of cast iron, which has poor toughness, the combustion chamber is constantly exposed to the risk of fracture due to residual stress during cylinder head and cylinder liner casting, thermal fatigue and thermal shock that the cylinder head and cylinder liner receive during engine operation. ing. Particularly, in the cylinder head, the so-called valve bridge portion between the intake port and the exhaust port and between these ports and the pre-combustion chamber hole or the fuel injection nozzle hole is
Since it is difficult to have a sufficient size and thickness in terms of the structure, the strength is weak, and there is a risk that breakage such as cracks or cracks may occur in these portions.

Conventionally, as a countermeasure against such a problem, for example, when casting a cylinder head, a dissimilar metal is cast into a place where high strength is required for reinforcement (see Japanese Utility Model Publication No. Sho 48-25923), a valve bridge portion. In addition, the cylinder head is reinforced by hardening the material according to the strength and weakness of thermal stress generated during engine operation (see Japanese Utility Model Publication No. 63-8831).

However, in particular, due to the recent increase in the output of the engine and the increase in the mechanical load at the same time as the thermal load, the risk of occurrence of this crack is increasing more and more, and it is sufficient to simply reinforce the portion having a large thermal stress. Not a countermeasure.

On the other hand, as part of the improvement of engine performance, the development of a technology for suppressing the thermal fatigue due to the excessive temperature rise by thermally insulating the surface around the combustion chamber is one of them. For example, as shown in FIG. 6 and FIG. As shown, it is known that a part of the cylinder head on the combustion chamber surface side is made of a ceramic material to prevent cracks from occurring and at the same time enhance the heat insulating effect (for example, Japanese Utility Model Publication No. 59-85348). See the bulletin). FIG. 6 is a plan view showing the cylinder head structure, and FIG. 7 is a sectional view taken along line AA of FIG. Between the intake port 41 and the exhaust port 42, a recessed portion 44 is formed by inserting a counterbore portion in the valve bridge portion of the cylinder head that grows in the fuel injection nozzle mounting hole 43, and the recessed portion 44 is filled with ceramics. Layer 45 is provided.

However, in the cast iron cylinder head, when converting a part of the combustion chamber surface side into ceramics, there is no technique for successfully joining the cast iron material and the ceramics, and the performance test is unavoidably performed by mechanical joining such as bolt fastening. It is the current situation.

Further, some exhaust manifolds have a ceramic port liner inserted therein for the purpose of improving turbo efficiency due to the heat insulation of the internal exhaust gas. In this case, when casting the exhaust manifold, a means for casting the ceramic liner at the same time is used, but since there is no joining between cast iron and ceramics, there is a problem that the ceramics will be damaged by vibration, impact, etc. during operation. Occurs.

Further, JP-A-62-298443 discloses a method for modifying the surface of solid particles. The surface modification method of the solid particles is such that other solid particles are embedded in the concave portions of the solid particles having various shapes of irregularities, holes and grooves, and the solid particles are softened, melted and deformed by using an impact type means. To enclose other solid particles. This method for modifying the surface of solid particles is achieved by using a powder impact device and its peripheral devices as shown in FIG.

As shown in FIG. 4, in the powder impact device H, a rotary disc 4 is supported by a rotary shaft 4 rotatably supported by a casing 1,
A plurality of impact pins 3 are arranged in the radial direction on the outer periphery of the rotating disk 2 with a space therebetween. The turntable 2 can rotate at a high speed, and a collision ring 5 is provided around the casing 1 along the outer peripheral raceway surface of the impact pin 3 with a certain space in the radial direction of the turntable 2. Further, an opening / closing valve 6 for discharging the capsule powder is provided in the notch portion which is formed by notching a part of the collision ring 5. The opening / closing valve 6 is opened / closed via the valve shaft 7 by the operation of the actuator 8. The impact chamber 13 provided between the outer periphery of the rotary disc 2 and the collision ring 5 has one end opening to a circulation port 14 formed in the inner wall of the collision ring 5 and the other end near the center of the rotary disc 2. A circulation circuit 9 that opens to the is communicated. The raw material of the capsule powder is introduced into the impact chamber 13 through the raw material supply chute 11 that connects the raw material hopper 10 and the circulation circuit 9, and the raw material is manufactured into the capsule powder in the impact chamber 13, and the capsule powder is It is discharged from the discharge chute 12. As a peripheral device of this powder impact device, a raw material measuring feeder 16, a raw material storage tank 17, a cyclone 21, a rotary valve 22, a bag filter 23, a rotary valve 24, a blower 25, a time control device 31, a metal on the surface of the ceramic particles in advance. It consists of a preprocessor 32, etc. used to deposit the particles.

[Problems to be Solved by the Invention]

Therefore, in order to solve these problems, as a means for joining the cast iron material and the ceramics, it is considered effective to use a method in which the ceramic particles are mixed with an appropriate amount of metal particles and sintered, and then cast into cast iron. According to this, the metal particles mixed with the ceramics and the cast iron molten metal are metallurgically bonded,
As a result, the ceramic and the cast iron are firmly joined.

However, the above method has the following problems. First, in the case of a part made of a mixture in which ceramics and metal particles are unevenly distributed, not only the heat resistance, heat insulation property, deformation resistance, etc., but also the durability strength of the part itself may be deteriorated. is there. Further, it is considerably difficult to manufacture a molded body in which ceramics and metal particles are uniformly mixed, and for that purpose, it is necessary to perform thorough quality control. Therefore, in order to solve the above problem, it is necessary to solve the problem of producing a molded body in which ceramics and metal particles are uniformly mixed.

An object of the present invention is to solve the above problems,
Embedding other solid particles in solid particles having various shapes of irregularities, holes, and grooves on the surface, and softening, melting, and deforming these solid particles using impact type means to enclose other solid particles. Focusing on the fact that it is possible to produce a capsule powder by uniformly adhering a number of metal particles over the surface of the ceramic particle with the ceramic particle as a nucleus to produce a capsule powder, and manufacturing a molded body using the capsule powder as a raw material, A ceramic cast-in member capable of producing a ceramic cast-in member by firmly bonding the body to cast iron by firing and casting, and ensuring uniform and good heat resistance, heat insulation, deformation resistance, etc. of the ceramic cast-in member. A method of manufacturing a member is provided.

[Means for Solving the Problems]

The present invention is configured as follows to achieve the above object. That is, according to the present invention, a step of adhering a large number of metal particles having a particle size smaller than the particle size of the ceramic particles onto the surface of the ceramic particles, and the impact of the high-speed air flow causes the metal particles to bite into the ceramic particles to produce a capsule powder. From a step, a step of forming a molded body of a predetermined shape from the capsule powder as a raw material, and a step of casting a cast iron material into the molded body and firing the molded body to produce a ceramics cast-in member. The present invention relates to a method for manufacturing a ceramics cast-in member having the same.

In the method for manufacturing a ceramics cast-in member, the ceramics cast-in member is a combustion chamber wall surface of a piston head.

Alternatively, in the method for manufacturing a ceramics cast-in member, the ceramics cast-in member is a lower surface portion of a cylinder head and / or an exhaust port.

Alternatively, in the method for manufacturing a ceramics cast-in member, the ceramics cast-in member is a wall surface of the exhaust manifold and a wall surface of the inlet portion.

Alternatively, in the method for manufacturing a ceramics cast-in member, the steps of firing the molded body to produce a sintered body, and casting a cast iron material into the sintered body to produce a ceramics cast-in member. I have.

[Action]

The method of manufacturing a ceramics cast-in member according to the present invention is
It is configured as described above and operates as follows. That is, in the method for manufacturing the ceramic cast-in member,
In the first step, metal particles are attached to the surface of the ceramic particles. The adhesion force at that time is due to the generally well-known Van der Waals force. However, at this stage, adhesion between different kinds of particles is not necessarily strong. Therefore, in the second step, the ceramic particles produced in the first step are used as nuclei to apply an impact force by a high-speed air flow to the mixture in which a large number of metal particles are attached to the surface of the ceramic particles, so that the metal A capsule powder is manufactured by biting particles. As a result, the fixed state between different kinds of particles becomes strong. Therefore, since the metal particles cover the surface of each ceramic particle with a strong adhesive force, when a molded body of a predetermined shape is manufactured using the capsule powder as a raw material, the molded body is converted into ceramic particles. A uniform mixed state with the metal particles can be obtained. Further, in the next step, a molded body made of capsule powder is sintered to manufacture a sintered body, and cast iron is cast into the sintered body. For example, a valve bridge portion of a cylinder head or an exhaust port of a cylinder head. Manufacture ceramics cast-in members such as liners and piston heads. In some cases, the molded body is sintered and cast iron is cast into the molded body to produce a ceramics cast-in member. At the time of firing the molded body and when casting the cast iron into the molded body or the sintered body, the metal particles covering the ceramics and the metal particles are metallurgically bonded to each other, and the bonded metal and the cast iron are bonded together. Since and are metallurgically bonded to each other by the metal components, the ceramic particles are cast into the metal, and the molded body of the capsule powder and the cast iron material are firmly bonded, resulting in heat resistance, heat insulation, and deformation resistance. A ceramic cast-in member with a high degree of strong bonding is produced.

〔Example〕

An embodiment of a method for manufacturing a ceramics cast-in member according to the present invention will be described below with reference to the drawings.

The method of manufacturing a ceramics cast-in member according to the present invention is
For example, capsule powder can be manufactured using the powder impact device shown in FIG. 4 and its peripheral devices. Since the powder impact device H has been described above, detailed description thereof is omitted here.

The method of manufacturing a ceramics cast-in member according to the present invention is
Although it mainly has three steps, the first step and the second step of them can be carried out as follows, for example, using the above-mentioned powder impact device and its peripheral devices.

As a raw material for the ceramic molded body, alumina (Al ₂ O ₃ ) powder is used as ceramic particles, and iron-based metal powder is used as metal particles.

The ratio of the particle size of the ceramic particles that are alumina powder to the particle size of the metal particles of the iron-based metal powder that coats the ceramic particles is appropriately about 10: 1, for example.

The treatment of the first step is performed in the preprocessor 32, and the metal particles M of the iron-based metal powder are deposited on the surface of the ceramic particles C of the alumina powder by the generally well-known Van der Waals force between the powders. Adhere to. The powder to be treated having the iron-based metal particles attached to the surface of the alumina particles is in a state as shown in FIG. 5 (A). Then, the powder to be treated is sent to the raw material storage tank 17.

Next, the process of the second step is performed by, for example, a powder impact device H as shown in FIG.

First, the on-off valve 6 is kept closed, and the rotating shaft 4 is driven to rotate the turntable 2 while introducing an inert gas into the apparatus. The rotation speed of the turntable 2 is 8000 to 16000r.
pm. As a result, an airflow is generated in accordance with the rotation of the impact pin 3 provided on the outer circumference of the rotary disk 2, and the fan effect based on the centrifugal force of this airflow causes the circulation circuit 14 to open to the impact chamber 13 from the circulation port 14 to the circulation circuit. A circulation flow of the airflow is formed around 9 and returning to the central portion of the rotary disk 2.

After this circulating air flow is formed, the powder to be processed stored in the raw material storage tank 17 is fed from the raw material measuring feeder 16 to the raw material hopper.
Throw in 10. The powder to be treated enters the impact chamber 13 from the raw material hopper 10 through the raw material supply chute 11. The powder to be treated, which has entered the impact chamber 13, is subjected to an instantaneous impact action by a large number of impact pins 3 of the turntable 2 rotating at high speed, and further,
It collides with the surrounding collision ring 5 and is again subjected to the impact action and the strong compression action. At the same time, the powder to be treated circulates in the circulation circuit 9 while being entrained in the flow of the circulating gas, returns to the impact chamber 13 again, and is again impacted by the impact.

The powder to be treated in which a large number of metal particles M are attached to the surfaces of the ceramic particles C is repeatedly subjected to the above-described impact action many times in a short time. The elapsed time is, for example, about 1 to 10 minutes. In the meantime, the surface of the ceramic particles C receives heat energy, so that the metal particles M or the ceramic particles C are softened, melted or deformed in a short time, and the metal particles M are spread uniformly over the entire surface of the ceramic particles C. The bite or the ceramic particles are covered with the metal particles M, and as shown in FIG. 5 (B), a capsule powder (composite powder) having the ceramic particles C as the core and covered with the metal particles M is manufactured. .

After the production of the capsule powder is completed, the on-off valve 6 is moved to the position shown by the chain line and opened, and the capsule powder is discharged from the impact chamber 13.

The capsule powder is discharged from the impact chamber 13 and the circulation circuit 9 within a short time (several seconds) by the centrifugal force acting on itself and the suction force of the blower 25, and passes through the discharge chute 12 to the cyclone. 21 and a bag filter 23, etc. are introduced into the powder collecting device. Next, the capsule powder is collected by the powder collecting device and discharged to the outside via the rotary valves 22 and 24.

In the third step, the capsule powder produced in the second step is molded into a predetermined shape, for example, the lower surface of the cylinder head, the cylinder liner, the exhaust port liner of the cylinder head, the wall surface of the exhaust manifold, and the like. A corresponding molded body is formed, the molded body is fired, and cast iron is cast into the molded body to manufacture a ceramic cast-in member.

The ratio of the metal component and the ceramic component of the ceramics cast-in member is 30:70, and it is possible to reduce the metal component. When strengthening heat resistance, heat insulation, deformation resistance, etc., the metal content is reduced. Further, in a device of many types such as vibration, impact, etc., the structure can be configured to increase the metal component for the purpose of improving brittleness of ceramics.

The method of manufacturing a ceramics cast-in member according to the present invention is
Although it can be achieved as described above, the ceramics cast-in member manufactured by the method for manufacturing the ceramics cast-in member can be used, for example, in the following.

First, as shown in FIGS. 1 (A) and 1 (B), a combustion chamber wall surface 19 of a piston head 18 constituting a piston 15 can be manufactured as a ceramics cast-in member. If the combustion chamber wall surface 19 is made of a ceramics cast-in member, it is possible to prevent cracks, etc. on the combustion chamber surface of the cast iron piston even when exposed to high temperature combustion gas and subjected to repeated thermal stress. it can.

Alternatively, as shown in FIG. 2 (A) and FIG. 2 (B), as the ceramics cast-in member, the inner wall surface 26 in the wall portion 27 of the exhaust manifold 20 or the connection with the cylinder head of the exhaust manifold 20. The molded body or the sintered body may be disposed only in the section, that is, the inlet portion to cast the cast iron to form the ceramics cast-in member, or the molded body or the sintered body may be used as the inner wall surface of the entire exhaust manifold 20. It may be arranged and cast iron may be cast.

Alternatively, as shown in FIGS. 3 (A) and 3 (B),
The ceramic cast-in member may be applied to the lower surface portion 33 of the cast iron cylinder head 28 or the exhaust port liner 30 of the cylinder head 28. Lower surface of cylinder head
When the 33 and the exhaust port liner 30 are made of a ceramic cast-in member, a structure rich in heat resistance, heat insulation, deformation resistance, etc. can be formed and cracks even when subjected to repeated thermal stress,
It is possible to prevent the occurrence of cracks and the like.

Further, although not shown, for example, the structure of the lower surface of the cylinder head, for example, the structure between the intake port and the exhaust port, or the mounting hole of the fuel injection nozzle between the intake port and the exhaust port has a crotch. The structure of the spot facing part of the valve bridge part of the cylinder head (see FIGS. 6 and 7)
The ceramic cast-in member according to the present invention may be manufactured by the method for manufacturing, and a ceramic layer may be formed on the site.

〔The invention's effect〕

The method of manufacturing a ceramics cast-in member according to the present invention is
Since it is configured as described above, it has the following effects. That is, according to the method for manufacturing a ceramics cast-in member, since the metal particles cover the surface of each ceramic particle with a strong adhesive force, the ceramic particles and the metal particles are uniform even without quality control. It is possible to make mixed products. Therefore, it is possible to manufacture an extremely excellent ceramics cast-in member having no unevenness in heat resistance, heat insulation, deformation resistance and the like. Moreover, the ceramic cast-in member manufactured by the manufacturing method of the present invention is such that metal particles covering the ceramic particles are metallurgically bonded to each other, and when the ceramic cast-in member is cast into cast iron, it covers the ceramics. Since the existing metal components are metallurgically bonded to the cast iron, the cast-in ceramics member can be firmly bonded to the cast iron material, eliminating the brittleness of the ceramics itself and improving heat resistance, heat insulation, deformation resistance, etc. Of course, strength, durability, etc. can be improved.

As described above, the method for manufacturing a ceramics cast-in member according to the present invention solves all the problems that have been obstacles when applying ceramics to a cast iron material. It becomes possible to apply to the structure that makes the most of the characteristics, and it becomes possible to expand the applicable range of ceramics all at once. For example, as the ceramics cast-in member manufactured by the method for manufacturing a ceramics cast-in member according to the present invention, the combustion chamber wall surface of the piston head, the lower surface portion of the cylinder head and / or the exhaust port, or the wall surface of the exhaust manifold and the inlet portion It can be used for wall surfaces.

[Brief description of drawings]

1 (A) is a perspective view showing an example of a piston head manufactured by the method for manufacturing a ceramics cast-in member according to the present invention, and FIG. 1 (B) is a combustion chamber wall surface of the piston head of FIG. 1 (A). FIG. 2 (A) is a perspective view showing an example, and FIG. 2 (B) is a perspective view showing an example of an exhaust manifold manufactured by the method for manufacturing a ceramics cast-in member according to the present invention.
Is a sectional view taken along the line 2B-2B in FIG. 2 (A), and FIG. 3 (A) is a schematic view showing an example of a cylinder head manufactured by the method for manufacturing a ceramics cast-in member according to the present invention. ) Is a perspective view showing an example of the exhaust port liner of FIG. 3 (A), and FIG. 4 shows a powder impact device and its peripheral devices used for carrying out the method of manufacturing a ceramics cast-in member according to the present invention. Schematic diagram shown in FIG. 5 (A)
Is an explanatory view illustrating the state in the first step showing the relationship between the ceramic particles and the metal particles, FIG. 5 (B) is an explanatory diagram illustrating the state in the second step showing the relationship between the ceramic particles and the metal particles, and FIG. FIG. 7 is a plan view showing an example of the cylinder head structure, and FIG. 7 is a sectional view taken along the line AA in FIG. C …… ceramic particles, H …… powder impact device, M ……
Metal particles, 18 ... Piston head, 19 ... Combustion chamber wall surface,
20 …… Exhaust manifold, 27 …… Wall, 28 …… Cylinder head, 29 …… Exhaust port, 30 …… Exhaust port liner, 33
...... Lower surface part.

Claims (5)

[Claims] 1. A process of depositing a large number of metal particles having a particle size smaller than that of the ceramic particles on the surface of the ceramic particles, and a process of causing the metal particles to bite into the ceramic particles by an impact action of a high-speed air flow to produce a capsule powder. And a step of forming a molded body having a predetermined shape from the capsule powder as a raw material, and a step of casting a cast iron material into the molded body and firing the molded body to manufacture a ceramic cast-in member. Manufacturing method of ceramics cast-in member. 2. The method for producing a ceramics cast-in member according to claim 1, wherein the ceramics cast-in member is a wall surface of a combustion chamber of a piston head. 3. The method for manufacturing a ceramics cast-in member according to claim 1, wherein the ceramics cast-in member is a lower surface portion of a cylinder head and / or an exhaust port. 4. The method for producing a ceramics cast-in member according to claim 1, wherein the ceramics cast-in member is a wall surface of an exhaust manifold and a wall surface of the inlet portion. 5. The method according to claim 1, further comprising a step of firing the molded body to produce a sintered body, and a step of casting a cast iron material into the sintered body to produce a ceramics cast-in member. Manufacturing method of ceramics cast-in member.