JPH10305347A - Mold and process for manufacture of hollow metal molding and hollow molding itself - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mold and process for manufacture of hollow metal molded products such as a reciprocating piston internal combustion engine, especially, as a cylinder, sleeve and the like for a large scale diesel engine, whereby the other machining ratio is comparatively decreased and the requisite for a modern high powered machine is satisfied in a view point of an ability to bear the working stress. SOLUTION: The mold 1 has an inlet 4 to feed a molding material 6 into a molding space 5. The molding space 5 is defined by plural molding faces 7, 8, 9 and receives the molding material 6. The mold 1 contains a permanent mold 3 and a sand mold 2, and the permanent mold 3 has the first molding face 9, and the sand mold 2 has the remained plural molding faces 7, 8, which decide the form and dimensions of the moldings. In the process for the manufacture of the hollow metal moldings, the first zone of the outside shape of the hollow moldings is formed by the permanent mold 3 and the second zone of the outside shape of the moldings is formed by the sand mold 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a hollow metal casting, i.e., a mold and a method for producing a casting, and a hollow casting produced by the same. It has two regions with thickness. In particular, the present invention relates to a mold and a method for manufacturing the cylinder sleeve of an internal combustion reciprocating piston engine, in particular, a large diesel engine.

[0002]

BACKGROUND OF THE INVENTION Internal combustion reciprocating piston engines, particularly the cylinder sleeves of large diesel engines used on ships and the like, experience high mechanical and thermal stresses during operation. The cylinder sleeve must withstand high pressures and temperatures, especially in the area of the explosion of the fuel mixture. Therefore, the cylinder sleeve must have a high strength to withstand the stresses caused by the explosion of the fuel mixture, especially in the explosion area.

[0003] In order to increase the strength of the cylinder sleeve in the region where the fuel mixture explodes during operation, the cylinder sleeve in that region always has a greater wall thickness than the other regions. This means that the cylinder sleeve has substantially two regions with different wall thicknesses. The first of the two regions has a large wall thickness and, according to common nomenclature, a color region (Kragen
bereich). Furthermore, the second area has a small wall thickness and, according to common nomenclature, the shirt area (He
mdbereich).

In many cases, cylinders of internal combustion engines are
The sleeve is formed by casting from cast iron, especially a cast iron alloy. Apart from the chemical composition of the alloy used as casting material, the physical and metallurgical properties of the cylinder / sleeve, such as structure, strength, elongation and friction properties, are greatly influenced by the evolution of the solidification of the casting material. Therefore, the mold and casting method used have significant implications for the properties of the cylinder sleeve.

[0005] Two casting methods for manufacturing cylinder sleeves are known. In the sand casting method, a liquid casting material, that is, a mixture is filled into a sand mold, and the sand mold is formed in advance based on a desired shape of a casting to be manufactured. Further, if necessary, an excess material is added as a finishing allowance. This type of sand mold is formed from a silica sand or other sandy mineral material to which a binder has been added in advance through a chemical hardening treatment or a heat hardening treatment, and the sand mold is always designed to be used only once. The problem with the cylinder sleeves produced by this is that the metallurgical structure, strength and elongation of the cylinder sleeves are of modern internal combustion reciprocating pistons.
It does not meet the requirements for engines, especially high power internal combustion reciprocating piston engines. This is mainly due to the evolution of the solidification of the casting material in the sand mold, in particular the solidification time is not ideal from a metallurgical point of view.

In a second type of casting, called gravity die casting, a cast iron mold (permanent mold) filled with a liquid casting material is used in most cases. Accordingly, the outer shape of the casting is formed by the metal mold in which the casting material solidifies. This type of permanent mold can always be used multiple times. However, in the gravity die casting method, it is necessary to separate the permanent mold from the casting after the casting has solidified, that is, cooled. For this reason, the outer shape of the manufactured casting is subject to relatively large geometric constraints. Due to this limitation of the boundary conditions, the geometric details of the profile of the casting cannot always be produced by the permanent mold method at a reasonable cost and effort. Therefore,
When manufacturing a cylinder / sleeve or the like, it is necessary to manufacture a casting through another relatively large-scale machining to achieve a desired outer shape of the cylinder / sleeve. This means that the profile of the casting deviates significantly from the desired final product profile. That is, another machining operation that requires time and cost must be performed subsequently, and the machining operation requires a large amount of material to be cut by a machining process that forms chips. This alternative machine operation is undesirable from an economic point of view due to the use of large amounts of casting material.

In the manufacture of particularly large castings such as cylinders and sleeves used in modern large high power engines,
The weight of the permanent mold introduces several problems. For example, a permanent mold filled with this type of casting material weighs tens of tons. It is then necessary to transport the permanent mold to another location in order to cool the filled permanent mold or to separate the permanent mold from the casting. However, many foundries do not have sufficiently powerful lifting equipment to transport filled permanent molds to another location. In order to install a sufficiently powerful lifting device, a remodeling operation requiring time and cost is required.

It is an object of the present invention to provide a hollow metal casting in which the spatial and temporal evolution of solidification in the casting is as ideal as possible and which allows a relatively small amount of material to be processed as a finishing allowance. It is to provide a mold and a method for producing an article. In particular, it is an object of the present invention to provide a relatively small amount of additional machining and an internal combustion reciprocating piston engine that meets the requirements of modern high power machines in terms of its ability to withstand working stresses (eg, strength, elongation). In particular, it is an object of the present invention to provide a mold and a method which enable the production of hollow metal castings such as cylinder sleeves for use in large diesel engines.

[0009]

SUMMARY OF THE INVENTION A mold for producing a hollow metal casting according to the invention from a casting material, in particular for producing a cylinder sleeve of an internal combustion reciprocating piston engine, in particular a large diesel engine. The mold is
An inlet is provided for guiding the casting material into the casting space, the casting space being defined by a plurality of molding surfaces and receiving the casting material. A mold according to the present invention includes a permanent mold and a sand mold, the permanent mold having a first molding surface, and the sand mold having a plurality of remaining molding surfaces that determine the shape and dimensions of the casting.

The mold and method according to the present invention have the advantages of both the sand mold method and the permanent mold method, respectively, without the above-mentioned problems. With the combination of the permanent mold and the sand mold according to the invention, the spatial and temporal evolution of solidification in the casting material can be optimized as detailed below.
As a result, the hollow casting according to the present invention is much more resistant to mechanical stress (eg, its strength and hardness) than castings manufactured using conventional casting methods or sand molds.
Having. Furthermore, the use of the sand mold of the mold according to the invention and the use of the same in the method according to the invention makes it possible to achieve a high flexibility with regard to the profile of the hollow castings formed by the same sand mold. As a result, only a relatively small amount of surplus material is required as a finishing margin.

The permanent mold of the mold according to the invention is preferably a one-piece product. This is because it is possible to prevent damage to the hollow casting due to heat generated at the interface between the two permanent molds abutting each other.

[0012] The permanent mold preferably has a plurality of conduits or passages for guiding a fluid, in particular air, to transfer heat inside or outside the permanent mold. This measure is advantageous because by allowing the warm air to flow through the conduit, the permanent mold can be easily preheated before injecting the liquid casting material. Furthermore, by using cold air or the like, a high-temperature permanent mold can be easily cooled after the hollow cast product is taken out. As a result, the permanent mold can be used after a short time to carry out a new casting process. There is an effective possibility of removing heat from the permanent mold during and / or after casting material injection.

In a preferred embodiment, the sand mold has a sand core and a sand jacket, one side of the casting space is defined by the sand core and the other side is defined by the sand jacket and the permanent mold.

The permanent mold is preferably a container having one open end. The container has an inner wall and a base, wherein the inner wall and at least a portion of the base form a first forming surface. By this means, a large contact surface is formed between the permanent mold and the casting material. This improves, and more particularly accelerates, the heat transfer between the casting material and the permanent mold.

It is advantageous for the base of the permanent mold element to have a recess and for the sand core to extend into the recess. Therefore, the sand core can be easily positioned at the center of the sand jacket and the permanent mold. This guarantees the radial symmetry of the hollow casting.

Making the distance between the sand core and the inner wall of the permanent mold greater than the distance between the sand core and the sand jacket is particularly advantageous in the production of cylinder sleeves. This forms in the permanent mold a thick wall region of the hollow casting corresponding to the collar region of the cylinder sleeve. This is particularly preferred for the solidification of hollow castings, since the thick wall region (color region) can be solidified more quickly than the thin wall region (shirt region) formed by the sand mold.

With regard to the most ideal spatial and temporal course of solidification, it is advantageous to match the design of the permanent mold to the area of the mold surrounded by the same.
This means, in particular in the production of cylinder sleeves, that the dimensions of the collar area of the hollow casting are taken into account in the design of the permanent mold. Therefore, it is preferable to use the following means.

The first molding surface forms approximately half of the plurality of surfaces of the mold that define an area of the casting space surrounded by the permanent mold. This forms a large contact surface through which heat can be transmitted from the casting material to the permanent mold.

The material volume of the permanent mold required for cooling the hollow casting is at least twice as large as the volume of the casting space surrounded by the permanent mold. This ensures that the heat capacity of the permanent mold is sufficient to allow rapid solidification of the collar area.

The wall thickness of the permanent mold is less than 1.5 times, in particular about 0.9 times, the distance between the sand core and the inner wall of the permanent mold. The method according to the invention is intended for hollow metal castings, in particular internal combustion reciprocating piston engines, in particular large diesel engines.
A hollow casting used in the manufacture of a cylinder sleeve for an engine, the hollow casting having a first region and a second region, wherein the wall thickness of the hollow casting in the first region is a hollow casting in a second region. Greater than the wall thickness. In the method according to the invention,
The casting material is poured into a mold and solidified therein. According to the invention, the profile of the hollow casting in the first region is formed by a permanent mold, and the profile of the hollow casting in the second region is formed by a sand mold.

For the reasons mentioned above in connection with the template according to the invention, the following are valid for the method according to the invention. Using the integral permanent mold for shaping the profile of the hollow casting in the first region;

Warming the permanent mold with a fluid, in particular air, before pouring the casting material. Cooling the permanent mold with a fluid, in particular air, during and / or after the casting of the casting material.

The mold and method according to the invention are particularly suitable for the production of cylinder sleeves having two zones with different wall thicknesses of internal combustion reciprocating piston engines, in particular large diesel engines.

The template according to the invention is particularly suitable for carrying out the method according to the invention.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of a mold according to an embodiment of the present invention for producing a hollow metal casting from a casting material has a first region and a second region, The same applies to the description of the method according to an embodiment of the present invention for producing a hollow metal casting in which the wall thickness of the hollow casting in the region is larger than the wall thickness of the hollow casting in the second region. Is done.

Further, the description of the following features is limited to the manufacture of cylinder sleeves for use with internal combustion reciprocating piston engines, especially large diesel engines. However, they apply equally to the manufacture of other hollow metal castings. The term "hollow casting" means a casting having an outer interface and at least one interface facing its interior space. Examples of such castings include hollow cylinders, sleeves or tubular structures.

The use of such cylinder sleeves, especially for large diesel engines, is common today. The cylinder / sleeve has a first region, referred to as a collar region, and a second region, referred to as a shirt region, wherein the average wall thickness of the cylinder / sleeve is greater in the collar region than in the shirt region ( Example: twice the size). The color region is the region where the explosion of the fuel mixture occurs during operation of the engine. Thus, the collar area is exposed to the maximum pressure and temperature, so that the collar area experiences the greatest stress.
To withstand this stress, the collar area always has a greater wall thickness than the other areas.

FIG. 1 is a longitudinal sectional view of a mold 1 according to a preferred embodiment of the present invention. The mold 1 has an inlet 4 for guiding the casting material 6 into the casting space 5. Casting space 5
Is defined by a plurality of molding surfaces 7, 8, 9. A plurality of casting surfaces that substantially affect the shape of the hollow casting are referred to as "forming surfaces." The plurality of molding surfaces 7, 8, 9 as a whole determine the shape of the casting, thereby forming the casting. The plurality of molding surfaces 7, 8, 9 are substantially equal to the contact surface between the casting material 6 and the mold 1.

FIG. 1 shows the mold 1 in a filling state, that is, a state in which the casting material 6 is filled in the casting space 5. For easier understanding, the casting material 6 is shown in FIG. 1 in two parts, which are indicated by different hatchings. The larger part indicated by reference numeral 6b indicates the shape of the finished cylinder sleeve, that is, the finished product. The smaller portion indicated by reference numeral 6a indicates a finishing allowance. Of course, this two-part representation of the casting material 6 is merely symbolic.

According to the invention, the mold 1 has a permanent mold 3 and a sand mold 2. The permanent mold 3 has a first molding surface 9,
The sand mold 2 has a plurality of remaining molding surfaces 7 and 8. In the embodiment shown in FIG. 1, the permanent mold 3 comprises an inner wall 31 and a base 3
2 and one end is opened (FIG. 2).
reference). The inner wall 31 forms the first molding surface 9 in cooperation with a part 32 a of the base 32. Base 3 of permanent mold 3
2 has a recess 322 (see FIG. 2), and the function of the recess 322 will be described in detail below. Further, the permanent mold 3 has a plurality of conduits 33 for passing a fluid, preferably air. Multiple conduits 3
3 is a plurality of passages provided inside the permanent mold wall, that is,
It can be a pipeline. The passages are cast inside the wall of the permanent mold. Apply heat to permanent mold 3 or
Alternatively, air can flow through a plurality of conduits 33 to remove heat from the permanent mold 3. Further, the permanent mold 3 is provided with a carrier device 34 which enables the permanent mold 3 to be lifted.
On its outer wall. The permanent mold 3 is manufactured from cast iron based on a conventional method or the like.

The sand mold 2 according to the embodiment shown in FIG. 1 has a sand core 21 and a sand jacket 22. The sand core 21 extends into a recess 322 provided in the base 32 of the permanent mold 3. The outer surface of the sand core 21 forms the molding surface 7. The sand jacket 22 is substantially in the form of a hollow cylinder or a truncated hollow cone and surrounds the sand core 21 substantially concentrically. Sand jacket 2 adjacent to sand core 21
The boundary surface 2 forms a molding surface 8. Based on the outer shape of the hollow cast product to be manufactured, the sand jacket 22 may be integrated or a plurality of molds 22a, 22b, 22c (FIG.
See also). The production of the sand mold 2 can be performed in a manner equivalent to the conventional sand mold method, and further detailed description is unnecessary. The sand jacket 22 is detachably connected to the permanent mold 3 while maintaining a seal. Permanent mold 3
And the outflow of the liquid casting material 6 located between the sand mold 22 can be prevented by conventional sealing means.

Accordingly, one side of the casting space 5 is defined by the sand core 21, ie the molding surface 7, and the other side is defined by the sand jacket 22 and the permanent mold 3, ie the associated plurality of molding surfaces 8, 9. It is defined. This means that the profile of the hollow casting is substantially determined by the first molding surface 9 of the permanent mold 3 and the molding surface 8 of the sand jacket 22.

In the preferred embodiment shown in FIG. 1, another sand element 10 is arranged in a recess 322 provided in the base 32 of the permanent mold 3,
Numeral 0 accommodates one end of the sand core 21 flush. The sand element 10 that can be manufactured by the same method as the conventional sand mold method is formed to position the sand core 21 at the center of the permanent mold 3. The radial symmetry of the hollow casting can be achieved by this means.

The outer shape of the hollow casting is formed by the permanent mold 3 in a first area, that is, an area having a larger wall thickness (color area). Therefore, the distance between the sand core 21 and the inner wall 31 of the permanent mold 3 is larger than the distance between the sand core 21 and the sand jacket 22 in the mold 1 shown in FIG. Furthermore, the mold 1 according to the present embodiment is designed for under-pour casting in which the liquid casting material 6 is guided from the lower end of the mold 1 into the casting space 5. For this purpose, the inlet 4 has an inlet passage 41. The inlet passage 41 extends through the center in the sand core 21 along the axis of the sand core 21. The entrance passage 41 communicates with the distributor 42,
The distributor 42 is disposed in a concave portion 322 provided in the sand element 10. The distributor 42 communicates the inlet passage 41 with the casting space 5.
As a result, the liquid casting material 6 is guided to the lower end of the casting space 5 through the inlet passage 41 and the distributor 42. An overflow container 11 which is filled with the casting material 6 when the casting space 5 is full is provided at the upper end of the casting space 5 (see FIG. 1). The overflow container 11 also functions as a compensation container. Casting space 5
The casting material 6 may be returned from the overflow container 11 into the casting space 5 as the volume of the casting material 6 therein decreases during solidification.

The mold and the method according to the invention can be designed for top casting. In top pouring casting, casting space 5
Is filled with a casting material 6 (see FIG. 1) poured from above. Top pouring can be performed through means such as a ring feeder (Ringspeisers) arranged at the upper end of the mold 1.

FIG. 2 is a longitudinal sectional view showing another example of the permanent mold 3. Most of the symbols shown in FIG. 2 have already been described in connection with FIG. These will be described again with reference to FIG. The difference in the other example of the permanent mold 3 shown in FIG. 2 is that the inner wall 31 is not flat and has a stepped portion 311. The step 311 allows the blank to be closer to the shape of the final product. As a result, the amount of subsequent machining required can be reduced. In the alternative embodiment of the permanent mold 3 shown in FIG. 2, two independent conduits 331 and 332 are provided inside the wall of the permanent mold 3 for guiding a fluid for transferring heat into and out of the permanent mold 3. Each conduit 331, 33
2 is formed as a pipe cast in the wall of the permanent mold 3, the pipe making two rounds around the permanent mold 3. The pipe extending from the first opening 331a or 332a extends inside the wall of the permanent mold 3 so as to be parallel to the outer surface of the permanent mold 3 and then extends upward through the wall, and furthermore, 3 again in the circumferential direction to reach the second opening 331b or 332b. To add or remove heat from the permanent mold,
A fluid, preferably air, may be passed through the plurality of conduits 331,332. Thus, for example, the permanent mold 3 can be easily preheated with warm air to prevent damage due to heat generated during the contact with the hot casting material 6. It is advantageous to preheat the permanent mold 3 to a temperature above 100 ° C. before pouring the casting material 6. After separating the hollow casting from the permanent mold 3, a plurality of conduits 33 are provided to cool the permanent mold 3 more quickly.
1,332. This allows the permanent mold 3 to be more quickly prepared for use in the next casting process. First area (color area) of hollow casting
Heat can be removed from the permanent mold 3 during solidification of the casting material 6, ie during cooling, to accelerate solidification therein. Further, after applying separation and protection measures, the permanent mold 3 can be heated with warm air to remove residual moisture.

The production of a cylinder sleeve for use in a large diesel engine with the mold 1 will be described in detail below.
First, at least one of the sand core 21 (see FIG. 1), the sand element 10, the sand jacket 22, and the plurality of molds 22a, 22b, 22c forming the sand jacket 22 are formed into a desired shape of a hollow casting. Based on conventional methods. The mold 1 is then divided into a plurality of parts and a permanent mold 3
The sand core 22 is adjusted and / or positioned at the center, and the sand jacket 22 is fixed to the permanent mold 3 with screws or the like.
Is sealed by sealing means.

The permanent mold 3 is preheated to a temperature exceeding, for example, 100 ° C. by means such as warm air flowing through the inside of the conduit 33. The preheating may be performed before assembling the mold 1. The liquid casting material 6 (usually cast iron alloy) is guided into the casting space 5 through the inlet passage 41 and the distributor 42.

The casting material 6 solidifies in the casting space 5, thereby forming a hollow casting. The outer shape of the hollow casting is formed in a first area (color area) by the first molding surface 9 of the permanent mold 3 and the remaining outer shape of the hollow casting is formed by the sand jacket 22 of the sand mold 2 in the second area. (Shirt area). After the casting material 6 has solidified, the sand mold 2
Together with the hollow casting can be lifted from the permanent mold 3 and even moved to another location for cooling. Therefore, the preparation of the permanent mold 3 can be already carried out for use in the next casting process. After the hollow casting has been sufficiently cooled in the sand mold 2, the hollow casting can be removed from the sand mold 2 and further post-processed until the cylinder sleeve assumes its final shape.

Since a particularly favorable temporal and spatial transition of the solidification of the casting material 6 can be realized, the permanent mold 3 of the invention
And the cooperation of the sand mold 2 is effective in the production of cylinder sleeves, i.e. hollow castings having two regions with significantly different wall thicknesses. In the first region with thick walls (the color region), heat is dissipated from the hollow casting through the permanent mold 3. Permanent mold 3 provides much more effective heat transfer than sand mold 2. As a result, a large heat flux is applied to the casting material and the permanent mold 3.
Between the contact surfaces. Thus, the hollow casting solidifies quickly in the collar area. Short solidification times in the collar region are desirable from a metallurgical point of view. This is due to the shorter solidification times that result in the formation of finer structures, i.e., structures containing smaller eutectic cells, in the hollow casting. As a result, in the most stressed collar region of the operating cylinder sleeve,
Effective mechanical properties such as high strength and large elongation are realized.

In the shirt region of hollow castings having a smaller wall thickness, the smaller heat flux present at the interface between the casting material 6 and the sand mold 2 has a satisfactory effect. This is because the amount of heat dissipated for solidification per unit area is smaller. Furthermore, the mechanical stress on the cylinder sleeve in the operating state is not as high in the shirt area as in the collar area. For this reason, a short clotting time in the shirt area is not as important as a short clotting time in the collar area. Therefore, the effect of the sand mold method, particularly the great flexibility of the outer shape of the hollow casting, can be utilized in the shirt region. Furthermore, the weight of the mold is smaller than if all of the molds were formed from permanent molds. As a result, the operation of the mold is simplified.

By combining the sand mold 2 and the permanent mold 3, the solidification of the hollow casting in the first region (color region) is reduced by the different thermal conductivity of the sand mold 2 and the permanent mold 3. The solidification of the hollow casting in the step (1) can be performed more rapidly. This type of spatial coagulation is effective. This is due to the fact that the casting material 6 in the shirt area is still liquid when the solidification in the collar area is already in progress. As a result, the casting material 6, which is still in a liquid state, can flow back from the shirt area into the collar area to compensate for the decrease in casting material volume due to solidification. This can prevent the problem of the formation of holes due to pipe or casting shrinkage. This has the effect of improving the mechanical properties of the collar area of the cylinder sleeve.

From the color region during solidification, the permanent mold 3
Is made spatially uniform by the integral structure of the permanent mold 3. Since this works effectively on the structure of the structure being formed, the integral structure of the permanent mold 3 is particularly preferred.

Furthermore, during the solidification of the casting material, heat can be removed from the permanent mold 3 in the collar area, for example by passing cool air through the conduit 33. This makes it possible to influence the temperature gradient through the permanent mold wall and to further accelerate the solidification of the hollow casting in the collar area.

The first molding surface 9 is the same as that of the permanent mold 3 as described above.
Having a portion 32a of the base 32 is effective for rapid solidification of the hollow casting in the collar region. This increases the contact surface that transfers heat from the casting material 6 to the permanent mold 3. Large contact surfaces contribute to rapid solidification of the collar area.

In the realization of the most effective spatial and temporal evolution of the solidification, in particular of the rapid solidification in the collar area, the multiple molding surfaces of the mold 1 defining the casting space 5 surrounded by the permanent mold 3 It is advantageous for about half of the surface to be formed by the first molding surface 9, that is, for the first molding surface 9 to occupy about half the size of the heat dissipating collar area surface. Further, the material volume of the permanent mold 3 required for cooling the hollow casting is at least twice as large as the volume of the casting space 5 surrounded by the permanent mold 3, that is,
Advantageously, the volume of material of the permanent mold 3 required for heat removal is at least twice the volume of the collar area. The wall thickness of the permanent mold 3 is preferably less than 1.5 times the distance between the sand core 2 and the inner wall 31 of the permanent mold 3, especially about 0.9.
It is twice. This distance is equal to the wall thickness of the collar area of the hollow casting.

These effective means will be described in detail below with reference to FIG. FIG. 3 schematically shows a part of the rotationally symmetrical color region (left side) of the hollow casting and a part of the permanent mold 3 (right side) which forms the outer shape of the color region.
FIG. 3 corresponds to the lower right corner of FIG.

In FIG. 3, the wall thickness of the permanent mold 3 is D
K, the material volume of the permanent mold 3 required for cooling is V
Shown by K. The term “volume of material required for cooling” means the volume area of the permanent mold wall directly facing the molding surface 9. For example, the support device 34 shown in FIG. 1 and the portion disposed below the sand core 21 on which the permanent mold 3 is placed are not portions of a material volume necessary for cooling.

The collar region of the hollow casting shown on the left side of FIG. 3 has an overall volume denoted by VG and a wall thickness denoted by DG. During the solidification of the casting material 6, the heat is dissipated from the heat dissipation surface O in the collar area.
The heat can be dissipated through G, and the heat is transmitted through the left part of the heat radiation surface OG located in the sand core 21 and the lower right part of the heat radiation surface OG located in the permanent mold 3 in FIG. The heat radiation surface OG is a casting space 5 surrounded by a permanent mold.
Has the same surface area as the plurality of surfaces of the mold 1 that define the region.

The above-mentioned effective means for optimizing the transition of coagulation in the example shown in FIG. 3 is as follows. The first molding surface 9 formed by the inner wall 31 of the permanent mold 3 and the part 32a of the base of the permanent mold 3 is about half the size of the heat radiation surface OG of the collar region. This forms a large contact surface between the collar area and the permanent mold 3, which is an effective heat conductor. The material volume VK of the permanent mold is at least twice the volume VG of the color area; Thus, the heat capacity of the permanent mold 3 is sufficient to allow rapid solidification in the collar area. -The wall thickness DK of the permanent mold 3 is equal to the wall thickness DG of the color region which is 1.
It is less than 5 times, especially about 0.9 times. Further, from the inner wall 31 of the permanent mold 3 to about one third of the wall thickness DK of the permanent mold 3
It is advantageous to extend a plurality of conduits 33 spaced apart by a length DL into the wall of the permanent mold.

Further, to promote rapid solidification of the collar region, a cooling element 15 (see FIG. 1) in the form of a metal cooling plate or the like is provided on the mold 1 located in the transition region between the collar region and the shirt region. It is effective to provide in the part.

When using the mold and the method according to the invention, the optimized spatial and temporal evolution of the solidification of the casting material 6 results in a cylinder cylinder used for internal combustion reciprocating piston engines, in particular diesel engines. A sleeve can be manufactured, and the cylinder sleeve has effective mechanical properties such as high strength and large elongation. As a result, the cylinder sleeve is also suitable for use on modern high power machines.

[0053]

As described in detail above, according to the present invention,
Internal combustion reciprocating piston engines that meet the requirements of modern high power machinery in terms of their ability to withstand relatively little machining and to withstand the stresses used, especially cylinder sleeves used in large diesel engines An excellent effect of enabling the production of a hollow metal casting.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a mold according to an embodiment of the present invention in a filled state.

FIG. 2 is a longitudinal sectional view showing another example of the permanent mold in the embodiment shown in FIG.

FIG. 3 is a partial longitudinal sectional view showing a part of a cylinder sleeve and a part of a permanent mold, respectively.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 mold, 2 sand mold, 3 permanent mold, 4 inlet, 5 casting space, 6 casting material, 7, 8, 9 molding surface, 21 sand core, 22 sand jacket, 31 permanent mold Interior wall, 3
2 ... permanent mold base, 32a ... part of the permanent mold base, 33,331, 332 ... conduit, 322 ... permanent mold base recess, DK ... permanent mold wall thickness, VK ... permanent mold material volume, VG: volume of the area of the casting space surrounded by the permanent mold.

Claims (17)

[Claims] 1. A mold for producing hollow metal castings from a casting material (6), in particular for producing cylinder sleeves of internal combustion reciprocating piston engines, in particular large diesel engines. An inlet (4) for guiding the casting material (6) into the casting space (5),
The casting space (5) is defined by a plurality of molding surfaces (7,8,9) and in a mold receiving the casting material (6), the mold (1) comprises a permanent mold (3) and a sand mold (2). Wherein the permanent mold (3) has a first molding surface (9) and the sand mold (2) has a remaining plurality of molding surfaces (7, 8) that determine the shape and dimensions of the casting. template. 2. The mold according to claim 1, wherein the permanent mold is formed as a single piece. 3. The permanent mold (3) has a plurality of conduits (33; 331, 332) for guiding a fluid, in particular air, to transfer heat to the inside or outside of the permanent mold (3). 3. The template according to 1 or 2. 4. The sand mold (2) has a sand core (21) and a sand jacket (22), one side of the casting space (5) is defined by the sand core (21) and the other side. Mold according to any of the preceding claims, wherein the part is defined by a sand jacket (22) and a permanent mold (3). 5. The permanent mold (3) is a container open at one end, the container comprising an inner wall (31) and a base (32).
5. The mold according to claim 1, wherein the inner wall (31) and at least a part (32 a) of the base (32) form the first molding surface (9). . 6. The base (32) of the permanent mold (3) has a recess (322) and the sand core (21) has a recess (3).
22. The mold according to claim 5, which extends into the inside. 7. The sand core (21) and a permanent mold (3)
A mold according to claim 5 or 6, wherein the distance between the inner core (31) and the sand core (21) is greater than the distance between the sand core (21) and the sand jacket (22). 8. The first molding surface (9) forms substantially half of a plurality of surfaces of the mold (1) which define a casting space (5) in a region surrounded by the permanent mold (3). A mold according to any one of claims 5 to 7. 9. The material volume (VK) of the permanent mold (3) required for cooling the hollow casting is at least 2 times the volume (VG) of the region of the casting space (5) surrounded by the permanent mold (3). The mold according to any one of claims 5 to 8, which has twice the volume. 10. The wall thickness (DK) of the permanent mold (3) is less than 1.5 times the distance between the sand core (21) and the inner wall (31) of the permanent mold (3), especially about 0. 6. The ratio is 0.9 times.
10. The mold according to any one of claims 9 to 9. 11. A method of manufacturing a hollow metal casting, particularly a cylinder sleeve of an internal combustion reciprocating piston engine, especially a large diesel engine, wherein said hollow casting comprises a first region and a second region. A wall thickness of the hollow casting in the first region is greater than a wall thickness of the hollow casting in the second region, the casting material (6) is injected into the mold (1), and In the method of solidifying in the mold (1), the outer shape of the hollow casting in the first region is formed by a permanent mold (3), and the outer shape of the hollow casting in the second region is formed by a sand mold (2). A method comprising the step of molding. 12. The method according to claim 11, comprising the step of using the integral permanent mold (3) for shaping the profile of the hollow casting in the first area. 13. The step of heating the permanent mold (3) with a fluid, in particular air, before pouring the casting material (6).
Or the method of 12. 14. The casting mold (6) wherein said permanent mold (3) is cast.
14. The method according to any one of claims 11 to 13, comprising the step of cooling with a fluid, in particular air, during and / or after the injection of the fluid. 15. A hollow casting made with a mold (1) according to claim 1, having two regions with different wall thicknesses, in particular an internal combustion reciprocating machine. Cylinder sleeves for piston engines, especially large diesel engines. 16. A hollow casting, in particular an internal combustion reciprocating piston engine, having two regions with different wall thicknesses and produced by the method according to one of the claims 11 to 14. Cylinder sleeves, especially for large diesel engines. 17. An internal combustion reciprocating piston engine having at least one cylinder sleeve according to claim 15 or 16, in particular a large diesel engine.