JPS63192550A - Production of fluid permeable product - Google Patents

Abstract

PURPOSE:To obtain a ceramic porous body having porous structure by fitting a ceramic material to a lost foam structure arranging space forming member in a skelton forming member formed by expendable material and sintering. CONSTITUTION:To the expendable forming mold composing of a synthetic resin foamed body 26 of the skelton forming member and a resin plate 28 of the space forming member, a coating of ceramic material is executed, and the ceramic layer is formed around skelton of the foamed body 26 and on surface of the plate 28. Next, by executing sintering operation, the ceramic material is sintered and at the same time, the expendable forming pattern 32 is expended. In this way, the ceramic porous body 22 providing the skelton part 38, which consists of the skelton 36 of three dimensional mesh structure having voids 34 mutually connected through in the inner part, and the box-like space forming part 42, in which the space 40 closed to the outer space and having the prescribed volume is formed, is obtd.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for manufacturing fluid-permeable products, and particularly to cast or cast products that have the property of allowing fluid to permeate through continuous pores formed inside. The present invention relates to a method for advantageously producing products such as those with improved fluid permeability properties without any metallurgical or mechanical treatment.

(Background Art) As a product such as a cast product that has continuous pores and has the property of being able to permeate fluid, the applicant of the present application previously proposed a patent application filed in 1983-
No. 246360, Japanese Patent Application No. 61-281467, Japanese Patent Application No. 61-304744, etc. disclose ceramics in which the skeleton itself forming the porous m weave is hollow, and continuous pores are formed within the skeleton as a whole. By using a porous body and injecting a predetermined matrix material into the gaps of the porous structure to form an integral structure, the pores formed within the framework of the porous structure of the ceramic porous body are utilized.
We have revealed new products that allow fluid to pass through, such as cast products, cast products, and sintered products.

Incidentally, in such a fluid permeable product, for example, a porous ceramic body having pores in the framework of a porous structure is placed at a predetermined position in a product cavity formed by an appropriate mold. Below, by supplying a predetermined matrix material into the product cavity, the ceramic porous body is embedded in a part of the product, and continuous pores through which fluid can pass are formed therein. Therefore, by forming fluid supply holes or discharge holes that communicate with the holes formed inside such products through post-processing, air float bases, air suction tables, bearings, etc. It becomes possible to manufacture parts, heat exchange members, filters, catalysts, etc. with a single structure extremely advantageously without adding difficult metallurgical or mechanical treatments.

However, in a fluid-permeable product in which a ceramic porous body is buried inside and fluid supply or discharge holes are formed to communicate with the pores, it is difficult to connect the fluid supply or discharge holes. With respect to the fluid pressure acting in the hole through the hole, a pressure loss will be caused depending on the distance from the fluid supply hole or the discharge hole. Therefore, depending on the shape of the fluid supply hole or the discharge hole, There is a risk that the pressure and flow rate distribution of the circulating fluid within the holes may become non-uniform.

Therefore, for example, pores in a porous ceramic body buried inside are opened on one side of the product to form a fluid ejection surface, and fluid supply holes communicating with the pores are formed in the wall of the product. In hydrostatic fluid bearings, air float bases, etc., which have a structure in which the In products where uniformity of fluid ejection amount is important, there has been a problem in that sufficient performance or characteristics cannot be obtained.

By the way, as a method to equalize the fluid pressure that is applied through the pores formed inside such products, it is possible to supply or discharge fluid to the back of the ceramic porous body embedded in such products. By forming a space as a fluid reservoir in which the pores communicate, and by opening all the pores facing the space in the ceramic porous body on a plane parallel to the fluid ejection surface to communicate with this space. ,
It is conceivable to make the distance from the fluid supply port to the ejection port uniform throughout the hole, but when forming such a space by mechanical processing, it is necessary to make the product at least two Since it has to be a divided structure, an increase in cost due to an increase in processing steps can be avoided, and the shape may be extremely difficult, so it cannot be called an effective method.

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and its purpose is to eliminate voids formed within the framework of a ceramic porous body embedded within a product. In order to improve the fluid permeability properties of a product to which fluid permeability is imparted by pores, a fluid reservoir is provided that communicates with the pore openings in at least a portion of a predetermined surface of the ceramic porous body. An object of the present invention is to provide a method that can advantageously produce a fluid-permeable product formed inside a fluid-permeable product without adding any metallurgical or mechanical treatment.

In order to achieve this object, the present invention is characterized in that the skeleton forming the porous structure itself is hollow, and continuous pores are formed in the ceramic porous body as a whole. By inserting a predetermined matrix material into the gaps in the porous structure to form an integrated structure, fluid can pass through using the pores formed in the framework of the porous structure of the porous ceramic body. When manufacturing a product that can be made to have a three-dimensionally continuous skeleton structure, a predetermined size made of a burnable material is attached to at least a part of a predetermined surface of a skeleton forming member made of a burnable material and having a three-dimensionally continuous skeleton structure. A predetermined ceramic material is attached to a combustible structure integrally provided with a space-forming member around the skeleton and on the surface of the space-forming member, and then fired. A skeleton part having continuous pores therein as a whole, which is formed by a ceramic material adhered to the skeleton forming member, and which is obtained by burning out the combustible structure; A ceramic structure having a space forming part formed of a ceramic material attached to a forming member and having a space of a predetermined volume inside into which the pores formed in the skeleton part are opened, The object of the present invention is to form a fluid reservoir in the interior of the product that is used as a body and communicates with the pores formed in the skeleton of the porous ceramic body.

(Specific Structure/Example) By the way, when manufacturing, for example, a fluid-permeable cast product according to the method of the present invention, as shown in FIG. By pouring a predetermined molten metal into a ceramic porous body having a specific structure as shown in FIG. A desired fluid-permeable cast product is produced, in which a fluid reservoir is formed inside the product that communicates with at least some of the pore openings on a predetermined surface of a ceramic porous body (structure). It will be done.

In FIG. 1, reference numeral 10 denotes a mold consisting of an upper mold 12 and a lower mold 14. Generally, a self-hardening mold sander using green mold sand or resin as a hardening medium is a permanent mold (mold mold). ) etc. Further, a molten metal 17 is poured into the mold 10 from a ladle 19 to the molten metal 16 and the runner 18.
through which it is guided into the casting cavity 20. A porous ceramic body 22 having a specific structure is placed at a predetermined position within the casting cavity 20.

In addition, in FIG. 1, the pores formed inside are on one side (surface) of the product as shown in FIG.
In order to obtain a cast product such as an air float base or an air adsorption table, which has a structure in which an exposed surface is formed by opening in the cavity, the porous ceramic body 22 is placed on the inner surface of the casting cavity 20 on one side. Although the ceramic porous body 22 is set in contact with the metal fittings 24 such as keren, the placement position and shape of the ceramic porous body 22 in the cast product are not limited in any way, and may be set as appropriate depending on the intended product. This is determined by the following. That is, in the method of the present invention, for example, as shown in FIGS. 6 and 7, the ceramic porous body 22 is exposed on the cylindrical inner circumferential surface so that a sliding surface is formed there. Products such as bearing members, which have a structure of It can be applied to various cast products such as catalysts and filters, and the shape of the ceramic porous body 22 is determined according to such products. Moreover, it is placed at an appropriate position within the casting cavity 20 using a keren, a core, or the like.

Here, the ceramic porous body 22 having a porous structure according to the present invention, which is placed and fixed in the casting cavity 20, is made of a burnable material having a three-dimensionally continuous skeleton structure. For a combustible structure in which a space-forming member of a predetermined size made of a burnt-out material is integrally provided on at least a part of a predetermined surface of a skeleton-forming member, the area around the skeleton and the space in the skeleton-forming member is It is obtained by attaching a predetermined ceramic material to the surface of the forming member and firing it to sinter it to burn out the combustible structure, which is attached to the skeleton forming member. A skeletal part is formed of a ceramic material and has continuous pores therein as a whole, and a space formed in the skeletal part formed by a ceramic material attached to the space-forming member is open. and a space forming part having a predetermined volume of space therein.

More specifically, such a skeleton forming member is made of a material with a low thermal decomposition temperature and has a three-dimensionally continuous porous skeleton structure, for example, as shown in FIG. Similarly, after foaming a resin such as ester-based urethane, a three-dimensional network structure skeletal structure obtained by removing the membrane-like substance (foamed membrane) remaining around the skeleton using compressed air, etc. The synthetic resin foam 26 and the like having the above structure are preferably used. On the other hand, the space forming member is made of a material with a low thermal decomposition temperature and has a solid structure, such as a resin plate 28 made of ester-based urethane, etc., as shown in FIG. is preferably used. The resin plate 28 is attached to the outer surface of the synthetic resin foam 26 corresponding to a portion where a fluid reservoir is to be formed in the intended cast product, which will be described later.
Using a burn-out adhesive 30 with a low thermal decomposition temperature, the synthetic resin foam 26 is integrally fixed so as to cover the skeletal gaps on the surface, thereby reducing its burn-out resistance as a combustible structure. A mold 32 will be formed.

Then, the burnable mold 32 constituted by the synthetic resin foam 26 as a skeleton forming member and the resin plate 28 as a space forming member is coated with a predetermined ceramic material according to a known method. Through this operation, a ceramic layer of a predetermined thickness is formed around the skeleton of the synthetic resin foam 26 constituting the burnable mold 32 and on the surface of the resin plate 28. Note that as the ceramic material to be attached to such a burnable mold 32, cordierite, alumina, SiC, mullite, zirconia, etc. may be selected as appropriate depending on the characteristics required for the target product.
It will be adopted.

The predetermined ceramic material is, for example, deposited in a slurry state, excess slurry is removed, and after drying, a firing operation is performed depending on the deposited ceramic material. Simultaneously with the sintering of the ceramic material, the burnable mold 32 is burnt out.

That is, by the firing operation of the ceramic material, the synthetic resin foam 26, the resin plate 28, and the adhesive 30 interposed between them are burned out, and as a result, as shown in FIG. A skeleton part 38 constituted by a three-dimensional network structure skeleton 36 having mutually continuous pores 34 therein;
A box in which a hole 34 located at a predetermined position of the outer surface of the skeleton portion 38 is opened and communicated with the outer surface, and a space 40 of a predetermined volume that is sealed from the outside space is formed inside. A ceramic porous body 22 having a body-shaped space forming portion 42 is obtained.

In addition, in the case where the space 40 inside the space forming portion 42 is formed with a large area or volume, a through hole is formed in the resin plate 28 as shown in FIG. By providing an appropriate number of through holes 45 and filling the ceramic material into the through holes 45, the space forming portion 42 is formed as shown in FIG.
However, it is desirable to form a reinforcing piece 46 within the space 40.

In particular, a ceramic porous body 2 having such a structure
2 is placed in the casting cavity 20, a molten metal 17 having a chemical composition controlled according to the physical properties required of the cast product is poured.

Although cast iron and cast steel are generally used as the molten metal 17, the present invention can also be advantageously applied to casting various metal products such as copper alloys and aluminum alloys. Therefore, it goes without saying that the molten metal 17 is appropriately selected depending on the raw material for the product.

Moreover, the molten metal 17 poured in this way is generally
As shown in FIG. 1, the molten metal is introduced into the casting cavity 20 through the inlet 16 and the runner 18, and fills the gap between the skeletons 36 of the three-dimensional network structure in the ceramic porous body 22. This completes the pouring operation.

As mentioned above, this molten metal 17 is not limited to 1ζ non-ferrous or ferrous metal, but when it is introduced into the casting cavity 20, a drop in temperature due to contact with the inner wall surface of the mold 10 cannot be avoided. Furthermore, this tendency is further exacerbated by the installation of the ceramic porous body 22.
Since cementite structure may occur in thin corners, etc., it is desirable to set the molten metal temperature at the time of pouring to be higher than normal. In addition, such molten metal 1
In order to uniformly infiltrate the molten metal 7 between the skeletal structures (inside the cells) of the porous ceramic body 22 and solidify it, it is desirable to set up a riser or the like to provide an appropriate molten metal head.

In the thus obtained cast product 48 that has been completely solidified, as shown in FIG.
A cast metal 50 is inserted into the cells of a skeleton portion 38 formed by a skeleton 36 having a three-dimensional network structure, and the cast metal 50 forms a matrix for the ceramic porous body 22. On the other hand, the skeleton 36 in the cast ceramic porous body 22
Intrusion of the molten metal 17 into the holes 34 within the holes 3
4 is prevented from being in a closed state, and the pores 34 are maintained in a communicating state.

In particular, in such a cast product 48, since the space 40 formed inside the space forming portion 42 of the ceramic porous body 22 is formed as a closed space as described above, the inside of the space 40 is Intrusion of the molten metal 17 into the casting product 48 can be prevented.
Inside, a fluid reservoir 5 of a predetermined volume communicates with the pores 34 formed in the skeleton 36 of the ceramic porous body 22.
2 will be formed.

It should be noted that, after solidification is completed, such a cast product 48 is subjected to finishing processing through the same processes as in normal casting work, such as breaking the frame, cooling, cleaning by shot blasting, etc., and finishing with a grinder. However, especially in the case of the cast product of the present invention, as described above, one surface of the ceramic porous body 22 embedded therein is exposed on one surface of the product, and the exposed surface is used for fluid intake or Products that are used as discharge surfaces, such as air float bases as shown in FIG. 5, bearings as shown in FIGS. 6 and 7, etc. skeleton 3
Since the openings of the holes 34 on the exposed surface of 6 are blocked by ceramics or cast metal 50, the holes 34 are closed by cutting or polishing the exposed surface. is opened to the outside, thereby obtaining the desired fluid-permeable cast product.

Therefore, according to the method described above, the voids 3 formed in the skeleton 36 of the skeleton part 38 by the space forming part 42 of the ceramic porous body 22 embedded in the cast metal.
4 allows a fluid reservoir 52 opened and communicated with a predetermined surface of the skeleton portion 38 to be formed in an arbitrary shape and at an arbitrary position simultaneously with casting and without adding any metallurgical or mechanical processing. It is possible.

Therefore, for example, as shown in FIG. 4, in an air float base 54 in which a fluid ejection surface 56 is formed by exposing the ceramic porous body 22 at its lower side, the ceramic porous body 22
A fluid reservoir 52 is formed at the back of the hole (34).
) on a plane parallel to the fluid ejection surface 56 and the fluid reservoir 5
2, and a fluid supply hole 57 is formed so as to communicate with the fluid reservoir 52, so that fluid is supplied to the hole through the fluid reservoir 52. The fluid pressure applied to the back openings of these holes can be made uniform over the entire surface, and the fluid jetted from the openings of the holes located on the fluid jetting surface 56 can be made uniform over the entire surface. This makes it possible to equalize the flow rate and pressure over the entire surface.

Further, as shown in FIGS. 5 and 6, the cylindrical ceramic porous body 22 is exposed at its inner circumferential surface, thereby forming a hydrostatic fluid bearing 58 with a fluid ejection surface 60. , while forming a fluid reservoir 52 extending in the circumferential direction on the outer peripheral surface of the ceramic porous body 22,
By forming the fluid supply hole 62 so as to communicate with the fluid reservoir 52, it is possible to equalize the flow rate and pressure of the fluid ejected from the fluid ejection surface 60 in the circumferential direction.

Furthermore, as shown in FIG. 7, in a filter 64 formed by completely embedding the ceramic porous body 22 inside, the pores formed in the ceramic porous body 22 are A fluid reservoir 52 is formed on the surfaces corresponding to the fluid supply side and fluid discharge side of (34), respectively, and a fluid supply hole 66 and a fluid discharge hole 68 are bored in a form that communicates with the fluid reservoir 52. By providing this, its fluid permeation properties can be improved and its performance can advantageously be improved.

That is, according to the method of the present invention, a cast product with excellent fluid permeation properties can be manufactured easily and at low cost without any special metallurgical or mechanical processing. Furthermore, by using the ceramic porous body 22 having a three-dimensional network structure as shown in the above embodiment, the distribution of the pores 34 formed in the cast product can be set uniformly throughout. It is extremely easy to process, and therefore has the advantage that excellent performance can be stably obtained in the product.

The above is based on a specific example of manufacturing a fluid-permeable cast product.
Although the present invention has been described in detail, the present invention is not to be construed as being limited only to the description of such specific examples and specific configurations related thereto; Also, a plastic material, a glass material, or even a ceramic material is used as the matrix material, and these materials are filled into the tissue gaps that form the framework of a predetermined ceramic porous body. It is also possible to manufacture the desired fluid-permeable product by sintering it to form an integral structure with a ceramic porous body.

In addition, the burnout property used in the method of the present invention 21
' As a skeleton forming member in the sculpture 32, in addition to the resin foam 26 having a three-dimensional network structure as illustrated, a comb-shaped body or a sword-shaped product made of a burnable material, or a product made of at least one component. Fabrics whose threads are made of burnt-out materials and which are woven using threads of a plurality of components can be well employed.

Furthermore, in this example, the pores in the skeleton in the skeleton portion formed using such a skeleton forming member are
In the fluid reservoir formed by the space-forming member, these pores do not need to be three-dimensionally continuous in the skeleton part itself since they are communicated with each other.

In addition, the burnable mold 32 in the embodiment is formed by integrally fixing the synthetic resin foam 26 as a skeleton forming member and the resin plate 28 as a space forming member using an adhesive 30. However, it is also conceivable to form the space forming member simultaneously with the formation of the skeleton forming member, for example.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments may be different from the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not depart from the spirit of the invention.

(Effects of the Invention) According to the present invention, the pores formed in the skeleton of the skeletal part by the space-forming part of the porous ceramic body embedded in the product can be formed on a predetermined surface of the skeletal part. The fluid reservoir that is opened and communicated with can be formed in an arbitrary shape and at an arbitrary position simultaneously with the molding operation of the product, without adding any metallurgical or mechanical processing. Fluid-permeable products with such fluid reservoirs can be advantageously manufactured with good manufacturability.

In the fluid-permeable product obtained according to the method of the present invention, the fluid supply or discharge hole is provided in a form that communicates with the fluid reservoir, so that all the holes opening into the fluid reservoir are connected to each other. On the other hand, a uniform fluid pressure can be applied thereto, and thereby the fluid permeability properties of such fluid permeable products can be improved very effectively.

Therefore, for example, in a product in which pores in the skeleton of a porous ceramic body buried inside the product are opened on one side of the product to form a fluid ejection surface,
By forming a fluid reservoir in which the hole opening at the back of the skeleton portion communicates on a plane parallel to the fluid ejection surface, the distance from the fluid supply port to the ejection port in the hole can be substantially reduced. This makes it possible to substantially equalize the fluid over the entire surface, thereby making it possible to extremely effectively equalize the fluid jetting pressure and jetting amount over the entire surface at the jetting surface. It is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing one step in an embodiment of the method of the present invention, FIG. FIG. 4 is an enlarged cross-sectional view of a main part showing a cast product obtained by the manufacturing method, and FIG. 4 is an enlarged cross-sectional explanatory view showing a combustible structure used in forming the porous ceramic body shown in FIG. It is. In addition, FIGS. 5 to 8 are
These are cross-sectional explanatory views showing specific examples of cast products obtained by the method of the present invention, in which FIG. 5 shows an air float base, FIG. 6 shows a hydrostatic fluid bearing, and FIG. 7 shows a structure similar to that in FIG. 6. FIG. 8 is a cross-sectional view showing the filter. 10: Mold 17: Molten metal 20: Casting cavity 22: Porous ceramic body 26: Synthetic resin foam 28: Resin plate 32: Burnable mold 34: Hole 36: Skeleton 38: Skeletal part 40: Space
42: Space forming part 48: Casting product 5
0: Cast metal 52: Fluid reservoir 54: Air float pace

Claims (1)

[Claims] A ceramic porous body is used in which the skeleton forming the porous structure is hollow, and continuous pores are formed within the skeleton, and a predetermined matrix material is placed in the gaps of the porous structure. By incorporating it into an integrated structure,
When manufacturing a product that allows fluid to permeate by utilizing the pores formed in the framework of the porous structure of the ceramic porous body, it is necessary to use a burnable material that has a three-dimensionally continuous framework structure. For a combustible structure in which a space forming member of a predetermined size made of a burnable material is integrally provided on at least a part of a predetermined surface of a skeleton forming member formed by A ceramic material attached to the skeleton forming member is obtained by attaching a predetermined ceramic material around the space forming member and on the surface of the space forming member, and then firing and sintering it to burn out the combustible structure. A skeletal part formed of a ceramic material and having continuous pores therein as a whole, and a pore formed in the skeletal part formed of a ceramic material attached to the space forming member to be opened. A ceramic structure having a space-forming portion having a predetermined volume of space therein is used as the ceramic porous body, and the voids formed in the framework of the ceramic porous body are filled inside the resulting product. A method for manufacturing a fluid-permeable product, characterized in that a communicating fluid reservoir is formed.