JPS6018417Y2 - insulation structure casting - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of the structure of a heat-insulating structure casting, and in particular, it has a new structure in which ceramics and/or cast-in metal are not damaged during its production, and the product is a cylindrical heat-insulating structure casting. It is an object of the present invention to provide a heat insulating structural casting having a structure that not only increases the exhaust gas temperature but also significantly reduces the temperature rise outside the pipe when used in the exhaust pipe of an internal combustion engine.

Parts that require heat insulation are required for the exhaust passages of internal combustion engines.

FIG. 1 is a longitudinal side view of a conventional cast-in ceramic exhaust pipe, and FIG. 2 is a longitudinal side view of a part (exhaust port) of a conventional cast-in ceramic cylinder head.

These are intended to increase the temperature of the exhaust gas, purify the exhaust gas, increase the output of the exhaust turbine, and reduce the power required for cooling water by increasing the insulation of the exhaust system parts of the internal combustion engine. It has a structure in which a metal material 02 for an exhaust pipe or an exhaust port, for example, cast iron, is cast into the outer peripheral surface of a ceramic oval body 01 having a cylindrical bottom shape.

However, when these conventional heat-insulating structural castings are produced by the conventional cast-in method, there is a drawback that the ceramic molded body and/or the cast-in metal are damaged due to thermal shock during pouring or shrinkage during solidification and cooling.

The inventors of the present invention have conducted extensive research into solving the gaps that occur when manufacturing the conventional heat-insulating structure castings, and have determined that by configuring the ceramic hollow body to alleviate thermal shock and shrinkage during manufacturing. He discovered that the drawbacks of the conventional technology could be completely overcome, and based on that knowledge he completed the present invention.

In other words, the present invention is an outer side of a cylindrical ceramic body formed integrally with a metal tube material (hereinafter referred to as a metal tube or metal material) interposed between the divided surfaces of a ceramic body formed into at least two parts. The invention relates to a heat-insulating structural casting made by casting metal.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

Figure 3 is a cross-sectional side view of a cylindrical ceramic (for example, for exhaust pipes) that is the main part of the inventive heat insulating structure casting, and Figure 4 is a prismatic cylindrical ceramic (for example, for exhaust pipes) that is the main part of the inventive heat insulating structure casting. Figures 5 and 6 are cross-sectional side views of the inventive heat insulating structure casting.
The figure is a cross-sectional side view of the mold for producing the heat-insulating structure casting of the present invention, No. 6.
The figure is a longitudinal side view of Fig. 5 viewed from the direction of the arrows ``--'', and Fig. 7 is a sectional side view of the inventive heat-insulating structural casting.

Hereinafter, a method of manufacturing a heat insulating structure casting according to the present invention will be explained with reference to FIGS. 3 to 7.

Figures 3 and 4 show the cylindrical ceramics and rectangular cylindrical ceramics that are the main parts of the inventive heat insulating structure casting, and the manufacturing status of the two-part type will be explained below with reference to the figures. do.

In FIG. 3, IA and IB are each S'
A semi-cylindrical ceramic with matching dividing surfaces,
These may be manufactured by cutting a cylindrical ceramic along a plane passing through the axis, or may be formed in advance into a semi-cylindrical shape.

As for the material, ceramics such as silicon nitride, fused silica, alumina, and zirconia can be used.

Note that the shape of the ceramic divided surfaces to be matched may be wavy, uneven, or the like.

Here, we will explain an example in which ceramics is divided into two parts parallel to the axis, but if necessary, in addition to the plane parallel to the axis, it can be divided into three by a plane that forms a certain inclination with the axis, for example, a plane perpendicular to the axis.
It goes without saying that the insulation structure may be divided into a plurality of parts, such as four parts, and although a one-layer insulation structure will be described, the insulation structure may be laminated if necessary.

3A and 3b are the semi-cylindrical ceramics 1A, respectively.
The metal material to be interposed between the dividing surface of the IB or the surface to be joined is a heat-resistant stainless steel pipe, but if necessary, the inside of the pipe may be cooled with a cooling medium such as water or air, or may be filled with a heat insulating material. , this metal material is coated with resin-based molding glue.

In this way, the semi-cylindrical ceramics IA and 1B are joined to form the cylindrical ceramic 1.

Similarly, in the case shown in Fig. 4, the semi-cylindrical ceramic IIA
and IIB are joined by metal tubes 13A and 13B coated with resin-based mold glue to form a rectangular cylindrical ceramic 11.

Next, a situation in which the cylindrical ceramic 1 is placed in a mold to produce the heat-insulating structural casting of the present invention will be described with reference to FIGS. 5 and 6.

In FIGS. 5 and 6, 4 is a mold divided into upper and lower parts, 5 is a cylindrical mold inner wall bored on the joint surface of the same mold 4, and 6 is both ends of the circular mold inner wall 5. A supporting member is disposed in the cylindrical ceramic 1 and a part thereof is inserted into the inner circumferential surface of both ends of the cylindrical ceramic 1, thereby forming a casting part 5A between the outer circumferential surface of the cylindrical ceramic 1 and the inner wall 5 of the mold. It is formed.

Reference numeral 7 denotes a sprue drilled so as to communicate from the upper part of the mold 4 to the casting part 5A from the side, and reference numeral 8 denotes a sprue bored in the upper part of the mold 4 so as to communicate with the casting part 5A.

From the sprue 7 of the mold configured as shown in FIG.
By pouring molten cast iron into the mold, it is possible to produce a heat-insulating structural casting z1 of the present invention, in which a cylindrical ceramic 1 is cast with cast iron 2, as shown in FIG.

Similarly, a rectangular tube-shaped heat insulating structure casting can be manufactured.

In addition, semi-cylindrical ceramics IA, IB, 11A, II
Metal material 38, 3B, 13A, 1 interposed on the joint surface of B
The shape of 3B may be wavy, 8-shaped, U-shaped, semicircular, circular, or square.

Further, it is more convenient to apply a mold coating or a heat insulating filler to the outside of the metal material, that is, the surface that comes into contact with the cast metal, so that the solidification of only this part will not be accelerated.

By interposing a metal material coated with resin-based molding glue or heat insulating filler between the divided surfaces of at least two or more divided ceramic bodies,
If the cast metal on the outside of the cylindrical ceramic to be formed generates shrinkage stress during solidification and cooling, the metal material deforms due to the shrinkage stress and the shrinkage stress is alleviated, thereby creating a heat-insulating structure casting without damaging the ceramic or the cast metal. can be produced.

Next, the effects of the heat insulating structure itself of the present invention will be described.

When the exhaust system parts of an internal combustion engine are manufactured as cylindrical heat insulating structure castings as described above, the exhaust gas temperature will be lower than the normal exhaust gas temperature (8
00 to 900℃), which is effective in purifying exhaust gas and improving fuel efficiency, and the temperature rise on the outside of the exhaust pipe is small. This has the effect of eliminating the need for a jacket, which also contributes to reducing the weight of the engine.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal sectional side views of a part of a conventional ceramic cast-in exhaust pipe and cylinder head. 5 and 6 are cross-sectional side views of rectangular cylindrical ceramics (for example, for exhaust pipes) and prismatic cylindrical ceramics (for example, for exhaust ports). 6 is a cross-sectional side view of a mold for producing a cylindrical heat-insulating structure casting, FIG. 6 is a longitudinal sectional side view of FIG. ,
Regarding.

Claims (1)

[Scope of utility model registration request] A heat-insulating structural casting made by casting metal on the outside of a cylindrical ceramic body which is integrally formed with a metal tube interposed between the divided surfaces of a ceramic rod-shaped body which is divided into at least two parts.