DE102010000450A1 - Method for the production of a hollow cast part with an internal cavity, comprises arranging a cavity-forming element with a hollow section open to part and an integral microporous element mounted on the element, in a mold - Google Patents

Abstract

The method comprises arranging a cavity-forming element (10) with a hollow section open to part and an integral microporous element (15) mounted on the element in a mold, where the hollow section (12) has same form like the cavity to be formed and the microporous element has micropores (15a) at the open part of the hollow section, and casting molten base metal-cast material in the mold so that the cavity-forming element is surrounded by the cast material, where the micropores permit the air and does not permit a molten base metal-cast material. The method comprises arranging a cavity-forming element (10) with a hollow section open to part and an integral microporous element (15) mounted on the element in a mold, where the hollow section (12) has same form like the cavity to be formed and the microporous element has micropores (15a) at the open part of the hollow section, and casting molten base metal-cast material in the mold so that the cavity-forming element is surrounded by the cast material, where the micropores permit the air and does not permit a molten base metal-cast material. The cavity-forming element comprises a main body (11), which is formed as the microporous element with a material, whose melting point is higher than the temperature of the molten cast material, when the hollow cast part is produced under use of the cavity-forming element. The hollow cast part is resistant against the molten cast material. The cast material is aluminum based metal. The main body is formed with a material such as metal based on iron, alloy of iron/manganese and titanium alloy. The microporous element is formed with a material such as stainless steel and low alloyed steel or with a ceramic material. The cast material is aluminum based metal and the size of the micropore formed in the microporous element is 60-200 meshes. The cavity serves as heat insulation section. An independent claim is included for a method for the production of a cavity-forming element.

Description

BACKGROUND OF THE INVENTION

Field of the invention

The The present invention relates to a process for producing a hollow casting with an internal cavity for insulation purposes and the like, for example, a heat-insulated one Piston for an internal combustion engine.

Technical background

Around a hollow casting having an internal cavity for thermal insulation purposes and the like, for example, a heat-insulated piston for an internal combustion engine, becomes a manufacturing process which includes: pre-introducing a void-forming Elements that have a hollow section with the same shape as one cavity to be formed, in a mold and casting of a molten parent metal casting material into the mold, thereby the introduced into the mold cavity-forming element of the Base metal casting material is enclosed.

The Cavity-forming element, for example, with a material formed, which has a higher melting point than that Base metal casting material. For example, a cavity-forming Considered an element comprising: a main body, the For example, consists of sintered Fe / Mn and the one part having open hollow portion, and a closure element, for example is made of a stainless steel plate and integrally on the main body is fixed to hermetically seal the open part of the hollow portion. If using a void-forming member having such a construction However, it can happen that during casting due to the heat of the molten metal air in the a hermetically sealed room representing the hollow section suddenly expands, causing the hollow section itself could deform and inflate.

As a void-forming element which overcomes this disadvantage, reference 1 ( Japanese Patent Publication (Kokoku) No. 2-36350A (1990)) or citation 2 ( JP Patent Publication (Kokoku) No. 3-9821 A (1991)) discloses a void-forming member obtained by allowing a solid substance which is solid at room temperature and convertible into gas or liquid at a temperature below the melting point of a parent metal casting material having the same shape as that to be forming cavity is formed and the solid substance is covered with a porous body, which is resistant to a molten parent metal casting material. In the formation of a hollow casting, the cavity-forming member is placed in a mold, and a molten parent metal casting material is poured into the mold and press-molded, thereby obtaining a casting enclosing the cavity-forming member. Then, in the casting, an opening is formed which communicates with the solid substance, and a heat treatment is performed at a temperature lower than the melting point of the casting of the base metal casting material and which is at least as high as the melting point of the casting solid substance, whereby the solid substance is converted into gas or melted, so that they can flow out through the opening and thus can be removed. After the solid substance has been removed, the opening is closed with a screw or the like, thereby obtaining a hollow casting having an internal cavity.

SUMMARY OF THE INVENTION

With the method for producing a hollow casting after a citations 1 and 2 can be used without the risk of inflation, the otherwise heat conditionally during the casting would consist of a hollow casting with a cavity obtained whose shape corresponds to the intended value. However, since each of the methods of documents 1 and 2 involves that the casting is provided with an opening to a gaseous or to be able to remove molten substance that the low-melting substance embedded in the hollow section is converted into a gas or a melt in a reheating process will and that the opening after the removal of this substance is closed again, the process is quite complex on the whole.

The The present invention was carried out before the background described. The primary object of the present invention is the disclosure a new method for producing a hollow casting, with a hollow casting with a cavity whose dimensions the intended values, using a simpler processing method can be generated. A second object of the present invention is the disclosure of a method for making a void-forming Elements used for such a procedure.

A method of manufacturing a hollow casting having an internal cavity according to the present invention includes: introducing a cavity-forming member having a partially open portion and an integral one the microporous member attached thereto into a mold, the hollow portion having the same shape as the cavity to be formed, and wherein the microporous member has, at least at the open part of the hollow portion, a number of micropores permitting the passage of air but not the passage of air allow molten parent metal casting material, and pour the molten parent metal casting material into the mold such that the cavity-forming element is enclosed by the cast base metal casting material.

According to the Production method of the present invention is molten metal poured into a mold, in which the cavity-forming element introduced has been. Although the void-forming element is heated and air in the hollow section expands, this air can thus escape through the micropores of the microporous element. Thus, it can not happen that the hollow section inflates. Furthermore, the molten metal does not pass through the microporous Element in the hollow section. Therefore, the shape of the hollow can Portion formed in the cavity-forming member, unchanged be kept, and a cavity whose dimensions are the intended Values are formed in the thus produced hollow casting. Because the main manufacturing process only one step of introducing a cavity-forming element in a mold and a step casting a molten parent metal casting material included in the mold, the manufacturing process can also be greatly simplified.

The The present invention may be directed to methods for making any hollow castings are applied. For example, the present invention on the preparation of a thermally insulated piston of a Internal combustion engine are applied, in which case the cavity is used as a heat-insulating section.

The The present invention also discloses a method of preparation a void-forming member for use in the above Method for producing a hollow casting, which comprises includes: introducing the microporous element into a Mold, positioning an object to be removed (hereafter also called an object to be removed), which is the same Shape as the trainee hollow section and that is designed to disappear under the influence of heat on the microporous element, casting a metallic Material into the mold and perform a heat treatment, so the object that should be removed disappears to one hollow section to form.

Based The above manufacturing process can be done easily a cavity-forming element can be created, which is a hollow Section having any shape. The material for the object to be removed can be any material and is not particularly limited as long as he is affected by the heat, with which a metallic material is melted, in the gaseous Condition transferred and thus made disappear can be. Examples of the object to be removed are including paper, plastic and the like.

Of the Main body of the cavity-forming element can with each metallic material are formed, whose melting point higher is the temperature of the molten parent metal casting material, when a hollow casting using the cavity-forming Elements is generated, and that is resistant to the molten parent metal casting material. If, for example the base metal casting material is an aluminum-based metal, For example, the main body of the void-forming member may include an iron-based metal powder. examples for a molding method is a sintering method and the like. Further, a material such as Fe / Mn alloy powder and titanium alloy powder may also be used become.

Of the Material for the microporous element of the cavity-forming Elements can also be any material whose melting point is higher is the temperature of the molten parent metal casting material, when a hollow casting using the cavity-forming Elements is formed, and that is resistant to the molten parent metal casting material. examples for Materials include metallic materials such as stainless steel or low alloy steel and ceramic materials. The material for the microporous element may be suitable Way considering the size the micropores formed in the microporous element the viscosity of the molten parent metal casting material and the like. If the base metal casting material An aluminum-based metal should have about 60 up to 200 mesh are provided.

According to the present invention can provide a hollow casting having a cavity, whose dimensions correspond to the intended values a simple machining process are generated.

BRIEF DESCRIPTION OF THE DRAWING

In the attached drawing show:

1A and 1B an embodiment of a Cavity-forming member used for a method of manufacturing a hollow casting according to the present invention;

2A to 2D an embodiment for the production of a void-forming element;

3 another embodiment for the production of a cavity-forming element;

4 another embodiment for the production of a cavity-forming element;

5 an embodiment in which the method for producing a hollow casting according to the present invention with reference to the in 1A and 1B shown cavity-forming element is executed;

6 a test piece used for a test;

7 the way of carrying out the experiment; and

8th a heat-insulating piston, which is produced by the method for producing a hollow casting according to the present invention.

10

Cavity-forming element

11

main body a void-forming element

12

hollow section

15

microporous Element of a cavity-forming element

15a

micropores a microporous element

16 16a, 16b

Material, which should be removed

17

mold

18

metallic material

20

Base metal casting material

21

molten metal

30

hollow casting

50

casting

60

thermally insulated Piston of an internal combustion engine, using a method for Production of a hollow casting according to the present invention Invention has been formed.

DETAILED DESCRIPTION THE PREFERRED EMBODIMENTS

The present invention will be described by way of embodiments with reference to the accompanying drawings. 1A and 1B show an embodiment of a void-forming member used for the method of manufacturing a hollow casting according to the present invention. 2A to 2D show an embodiment for the production of a void-forming element. 3 shows a further embodiment for the production of a cavity-forming element. 4 shows a further embodiment for the production of a cavity-forming element. 5 shows an embodiment in which the method for producing a hollow casting according to the present invention with reference to the in 1A and 1B shown cavity-forming element is executed. 6 shows an example of a heat-insulating piston, which is formed by the method for producing a hollow casting according to the present invention.

A cavity-forming element 10 has a main body 11 and a microporous element 15 on, as in the lateral perspective view of 1A and in the cross-sectional view of 1B shown. In this example, the main body 11 of cylindrical shape, and a hollow section 12 , which is also cylindrical in shape, is in the main body 11 formed so that the downwardly directed side of the hollow section 12 is open. It should be noted that the shape of the hollow section 12 Overall, any shape can be as long as part of the hollow section 12 open and the other part of the hollow section 12 from the main body 12 is enclosed airtight.

The microporous element 15 has a number of micropores 15a on and is on the side on which the open surface of the hollow body 11 is integral with the main body 11 connected. In the drawing shown here has the microporous element 15 essentially the same size as the bottom of the main body 11 , However, the microporous element can 15 have any size, as long as it is at least part of the hollow section 12 can cover.

As in 5 shown is the size of the micropores 15a that are in the microporous element 15 are formed, designed so that a molten metal 21 made of base metal cast material 20 for casting a hollow casting 30 on the basis of the cavity-forming element 10 is not used by the micropores 15a can pass through. The size of the micropores 15a can range from 60 to 200 mesh when the molten metal 21 is an aluminum-based metal as described above.

Both the main body 11 as well as the microporous element 15 of the void-forming element 10 can be formed from a suitable material whose melting point is higher than the temperature of the molten metal 21 from the base metal cast material 20 , to pour the hollow casting 30 on the basis of the cavity-forming element 10 is used, and the opposite of the parent metal casting material 20 is stable. For example, the main body exists 11 made of a parent metal, and the microporous element consists of a stainless steel grid plate.

2A to 2D show a method for producing the void-forming element 10 , In this method, first, the microporous element mentioned 15 prepared, and a material to be removed 16 (hereinafter also referred to as material 16 which is to be removed, for example) made of paper, as in 2A represented arranged at it. The material 16 which is to be removed has the same three-dimensional shape as a cavity formed in the hollow casting 30 which is to be obtained should be trained. After the microporous element 15 with the material to be removed arranged thereon 16 in a suitable mold 17 was used, as in 2 B is shown, powder of a suitable metallic material described above 18 supplied from above to fill the mold as in 2C and then the powder is molded. Then, the molded element becomes the mold 17 taken out, and a sintering treatment is performed. The heat of the sintering treatment burns the material to be removed 16 and the resulting fuel gas passes through the micropores 15a of the microporous element 15 issued. Thus, as in 2D shown, the cavity-forming element 10 get that the main body 11 and the microporous element 15 and that the inner hollow section 12 having. It should be noted that the metallic material 18 does not have to be metal powder, as long as it can be brought into a desired shape by heating. In addition, a sintering treatment does not necessarily have to be performed.

3 shows another method for producing the void-forming element 10 , Here are two to be removed materials 16a and 16b , which are shaped differently than the material to be removed 16 on the microporous element 15 arranged. When the in 2 B to 2D illustrated steps using the materials to be removed 16a and 16b can be performed, a cavity-forming member may be formed, which has two hollow portions which are shaped differently. Of course, it is also possible a variety of pieces of materials to be removed 16 to use with the same shape or three pieces of materials to be removed 16 to use with different shapes. As a result, the production of the void-forming element 10 with any number of hollow sections 12 of any shape facilitated by the application of this manufacturing process.

4A and 4B show another method for producing the void-forming element 10 , This becomes the main body 11 with the aforementioned hollow section 12 one side of which is open, formed by a suitable, conventionally known shaping method or machining method as in 4A shown. Then, the mentioned microporous element becomes 15 integral with the underside of the main body by a suitable method 11 attached, whereby the cavity-forming element 10 is finished as in 4B shown.

5 shows an embodiment in which the hollow casting 30 using said void-forming element 10 is formed. In this example, the void-forming element becomes 10 so in a mold 50 used that microporous element 15 is placed at the top, and the molten metal 21 of the base metal casting material 20 gets into the mold from above 50 cast. The microporous element 15 has, as already described, a number of micropores 15a on, the passage of air, but not the passage of the molten metal 21 from the base metal cast material 20 enable. Air in the hollow section 12 which has expanded due to the heat of the molten metal is passing through the micropores 15a from the hollow section 12 issued. Thus, the hollow section does 12 no change in shape. Furthermore, it can not happen that the molten metal 21 in the hollow section 12 penetrates.

The pouring of molten metal 21 from the base metal cast material 20 causes the cavity-forming element 10 from the parent metal casting material 20 is enclosed, causing the hollow casting 30 is obtained. In the hollow casting thus produced 30 a cavity is formed which is shaped in the same way as the hollow section 12 that in the cavity-forming element 10 is trained. There are cases where the joining plane is not alloyed if an aluminum-based metal having a sintered body embedded therein is poured. To solve this problem, the cavity-forming element 10 preferably subjected to a aluminizing treatment with molten aluminum for about one to two minutes before it enters the mold 50 is used.

The inventors have made a trial to investigate whether the microporous element 15 allowed the passage of a molten metal. 6 shows a test piece TP, which is used for the experiment, and 7 shows the implementation way of the experiment. As the test specimens, TPs, two types of thin SUS304 plates (60 mesh and 200 mesh) were used as microporous elements 15 used, and each plate was between iron rings 19a and 19b arranged. As in 7 Each of the two test specimens, TPs, was placed in the mold 50 used, and aluminum melt (AC8A) 21 was poured at a temperature of 720 ° C so that it enclosed the test piece TP. After cooling, the resulting casting was removed and its backside was observed. It was found that the region within the iron ring 19b which was below the test specimens, the TPs, was hollow, and the microporous element 15 was visible from the bottom. Thus, the experiment could confirm that the presence of the microporous element 15 the passage of a molten metal 15 does not allow.

8th shows a thermally insulated piston 60 an internal combustion engine having a cavity as a heat-insulating portion, which communicates with the hollow portion 12 the void-forming element 10 was trained. The thermally insulated piston 60 is made by casting the base metal casting material 20 formed in a mold (not shown), while the cavity-forming element 10 is arranged in the mold. The hollow section (cavity) 12 the void-forming element 10 serves as a heat-insulating section.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - JP 2-36350A [0004]
• - JP 3-9821 A [0004]

Claims (9)

Method for producing a hollow casting with an internal cavity, comprising: Arranging a cavity-forming Elements with a partially open hollow section and an integral attached microporous element in a mold, wherein the hollow portion has the same shape as the trainee Cavity, and wherein the microporous element at least on open part of the hollow portion has a number of micropores, the passage of air, but not the passage of a molten one Allow base metal casting material; and Pouring the molten parent metal casting material in the mold, so that the void-forming element of the cast base metal casting material is enclosed. Method for producing a hollow casting according to claim 1, wherein the cavity-forming member is a main body with the hollow section and the one on the side where the open one is Surface of the hollow portion is integral to the main body having attached microporous element, and wherein both the main body as well as the microporous element is formed with a material whose melting point is higher is the temperature of the molten parent metal casting material, if the hollow casting using the cavity-forming Element is generated, and that is resistant to the molten parent metal casting material. Method for producing a hollow casting according to claim 2, wherein the base metal casting material a metal is based on aluminum, the main body of the cavity-forming Elements is formed with a material selected is from the group consisting of iron-based metal, Fe / Mn alloy and titanium alloy, and the microporous element with a metallic material selected from the group consisting of stainless steel and low alloy steel, or is formed with a ceramic material. Method for producing a hollow casting according to one of claims 1 to 3, wherein the base metal casting material An aluminum-based metal is and the size the micropores formed in the microporous element in the range of 60 to 200 mesh. Method for producing a hollow casting according to any one of claims 1 to 4, forming a heat-insulated Piston for an internal combustion engine comprising, wherein the Cavity serves as a heat-insulating section. Process for the preparation of the cavity-forming Elements responsible for the process of making a hollow Casting part according to one of claims 1 to 4 is used, full: Arranging the microporous element in one mold; Positioning an object to be removed on the microporous Element, wherein the material to be removed has the same shape like the trainee hollow section and designed for it is to disappear under the influence of heat; to water a metallic material in the mold; and Carry out a heat treatment, so that the material to be removed disappears to form the hollow section. Process for the preparation of the cavity-forming An element according to claim 6, wherein the object to be removed is paper or plastic is. Process for the preparation of the cavity-forming Elements according to claim 6 or 7, wherein the metallic material is a powder of metallic material and a sintering treatment is carried out following a compression molding, so that the object to be removed disappears. Process for the preparation of the cavity-forming Element according to one of claims 6 to 8, wherein two or more objects to be removed on the microporous element be arranged, with the objects to be removed the same or have different shapes.