JP2008080369A - Core for forming water jacket of cylinder block, and method for casting cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a core for forming a water jacket of a cylinder block, by which accurate positioning of the cylinder liner is conducted without using a mandrel. <P>SOLUTION: A core 2 for forming a water jacket of a cylinder block includes a cylindrical inner side part 2a and outer side parts 2b, 2b. The cylindrical inner side part 2a is attached to and formed integrally with an inner peripheral surface 1e of a cylinder liner 1, and is fixed to a core fixing part 12a of a cylinder block casting mold. The outer side parts 2b, 2b are formed on the outer side of an outer side surface 1f of the cylinder liner 1, being separated with a predetermined space. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a core for forming a water jacket for a cylinder block of an engine and a method for casting the cylinder block.

  Conventionally, the technique regarding the core for water jacket formation of the cylinder block which made the collapsible sand core the basic material is known, and the literature which discloses the structure of this core also exists (for example, refer patent document 1). .

For example, in Patent Document 1, in a collapsible sand core for a water jacket surrounding a cylinder of a cylinder block, the water jacket is formed by casting the collapsible sand core together with a mandrel integrated with a cylinder liner. The technology is disclosed.
As disclosed in Patent Document 1, conventionally, in order to position the cylinder liner, a mandrel which is a separate component from the core has been used.

  However, if a mandrel is used as in the prior art, after casting, in addition to the core material recovery step, a process for recovering the mandrel is required, and it is considered that the number of man-hours is large.

  In addition, since the mandrel, which is a separate member from the cylinder liner and core, is used, the number of parts is large, and there are variations in the position accuracy of the cylinder liner after product completion due to manufacturing errors inherent to the mandrel. It is also possible to do.

For example, Patent Document 2 discloses a structure in which a cylinder liner is fixed to a mandrel using the elastic force of a spring. Thus, the cylinder liner is securely attached to a mandrel made of metal. In order to fix, a mechanical mechanism is required. Also, high positioning accuracy may be required in the relationship between the cylinder liner and the mandrel.
Thus, it is thought that it will have many problems by using the mandrel which is another member.
Japanese Patent No. 2579004 Utility Model Registration No. 2529290

  Accordingly, the present invention relates to a core for forming a water jacket for a cylinder block, and uses a core that enables highly accurate positioning of a cylinder liner without using a mandrel, and the core. We propose a new casting method.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, as described in claim 1,
A cylindrical inner part, which is integrally formed on the inner peripheral surface of the cylinder liner and fixed to the core fixing part of the casting mold of the cylinder block;
And an outer portion formed at a predetermined interval outside the outer peripheral surface of the cylinder liner.

Moreover, as described in claim 2,
The core is molded by pouring a collapsible core material into a mold for molding a core having a cavity that houses the cylinder liner, and is removed from the cylinder liner integrally. It is what.

Moreover, as described in claim 3,
The cavity has a configuration in which the inner portion and the outer portion are continuously formed.

Moreover, as described in claim 4,
A rod-shaped member is inserted into the cavity to form a missing portion of the core material, and a runner is formed in an outer portion of the core.

Moreover, as described in claim 5,
A cylindrical inner part, which is integrally formed on the inner peripheral surface of the cylinder liner and fixed to the core fixing part of the casting mold of the cylinder block;
A core for forming a water jacket of a cylinder block, having an outer portion formed at a predetermined interval outside the outer peripheral surface of the cylinder liner,
After casting the cylinder block by casting the inner portion fixed to the core fixing portion,
A method for casting a cylinder block is provided in which a water jacket of the cylinder block is formed by dissolving and removing the core in water.

  As effects of the present invention, the following effects can be obtained.

  Since the mandrel is not required as in the prior art, it is possible to obtain high dimensional accuracy in the cylinder block in the product state without being affected by the manufacturing error inherent in the mandrel.

  Further, in claim 2, after the cylinder block is cast, the process of collecting the mandrel in the prior art is not necessary, and the cylinder block can be manufactured with fewer processes.

  In claim 3, an open deck type cylinder block can be formed.

  According to a fourth aspect of the present invention, a closed deck type cylinder block can be configured.

  Further, in the fifth aspect, after the cylinder block is cast, the process of collecting the mandrel in the prior art is not necessary, and the cylinder block can be manufactured with a small number of processes.

As shown in FIGS.
The core 2 for forming the water jacket of the cylinder block is
A cylindrical inner portion 2a formed integrally with the inner peripheral surface 1e of the cylinder liner 1 and fixed to the core fixing portion 12a of the casting die of the cylinder block;
The core 2 for forming a water jacket of the cylinder block has outer portions 2b and 2b that are formed outside the outer peripheral surface 1f of the cylinder liner 1 at a predetermined interval.

  Further, as shown in FIG. 1, the core 2 is formed by pouring a collapsible core material into a core molding die having a cavity 23 in which the cylinder liner 1 is housed. It is supposed to be removed from the liner 1 integrally.

  Further, as shown in FIG. 3, the cavity 23 is configured such that the inner portion 2a and the outer portions 2b and 2b are continuously formed.

  Further, as shown in FIGS. 4 to 6, pins 30 and 30 as rod-shaped members are inserted into the cavity 23 to form the missing portion of the core material, and the outer portions 2b and 2b of the core 2 are formed. The runners 2s and 2s are formed.

Also, as shown in FIGS.
The cylinder block casting method is
A cylindrical inner portion 2a formed integrally with the inner peripheral surface 1e of the cylinder liner 1 and fixed to the core fixing portion 12a of the casting die of the cylinder block;
A core 2 for forming a water jacket for a cylinder block, having outer portions 2b and 2b formed at a predetermined interval outside the outer peripheral surface 1f of the cylinder liner 1;
After casting the cylinder block by casting the inner portion 2a fixed to the core fixing portion 12a,
A water jacket of a cylinder block is formed by dissolving and removing the core 2 in water.
Hereinafter, it demonstrates in detail using figures.

FIG. 1 and FIG. 2 show the configuration of a mold (mold for molding a core) for molding a core to be integrated with the cylinder liner 1.
In this figure, 21 is an upper mold and 22 is a lower mold, and a cavity 23 (FIG. 1) for molding the core is formed in a clamped state.

  As shown in FIGS. 1 and 2, the upper die 21 is inserted into the cylinder liner 1 in a cylinder coaxially with the center line of the cylinder liner 1, and the opening of the tip end portion 21 b is formed in the cylinder liner 1. The cylinder part 21a arrange | positioned in the bottom part vicinity is formed. The cylindrical portion 21a is provided with a vertical through hole 21c, and a material pouring port 21d is opened at an upper end portion thereof. The core material is injected from the material inlet 21d.

Further, as shown in FIG. 1, a cylindrical space 23 a is configured by providing a predetermined interval between the outer peripheral surface 21 e of the cylindrical portion 21 a and the inner peripheral surface 1 e of the cylinder liner 1.
In addition, by providing a predetermined space between the tip 21b of the cylindrical portion 21e and the lower end portion 1b of the cylinder liner 1, a disk-shaped space 23b is formed below the space of the cylindrical shape 23a. I am doing so.
The space 23a and the space 23b constitute a cylindrical cavity whose upper side is opened between the cylindrical portion 21a and the cylinder liner 1.

Further, as shown in FIG. 1, the lower mold 22 is provided with a cylindrical portion 22a having an open upper side for inserting the cylinder liner 1 therein. The outer peripheral surface 1f of the liner 1 is in contact.
Further, the lower end portion 1b of the cylinder liner 1 is abutted against the bottom surface 22b of the cylindrical portion 22a, and the upper end opening portion 22g of the cylindrical portion 22a and the upper end portion 1c of the cylinder liner 1 coincide. I am going to do that. In other words, the vertical length of the cylinder liner 1 and the depth of the cylindrical portion 22a coincide with each other.

  Further, as shown in FIG. 1, the upper die 21 is formed with a wall portion 21n for surrounding the cylindrical portion 22c of the lower die 22 with the cylindrical portion 21a in the clamped state. By providing a predetermined interval between the inner peripheral surface 21m of the portion 21n and the outer peripheral surface 22m of the cylindrical portion 22c of the lower mold 22, a space 23c surrounding the outer periphery of the cylindrical portion 22c of the lower mold 22 is formed. It has become so.

  As shown in FIG. 1, in the upper mold 21, the space 23 d is configured by providing a predetermined space between the upper end opening portions 22 g of the cylindrical portion 22 a of the lower mold 22, so that the space 23 d A series of cavities 23 are formed by communicating the outer space 23 d of the cylindrical portion 22 a with the inner spaces 23 a and 23 b of the cylinder liner 1.

  As shown in FIGS. 1 and 2, positioning portions 22p and 22p that contact the inner peripheral surface 21m of the wall portion 21n of the upper mold 21 are provided at the base end portion of the cylindrical portion 22c of the lower mold 22. Thus, the positioning between the upper mold 21 and the lower mold 22 is performed with high accuracy, and the relative position between the cylinder portion 21a and the cylinder liner 1 can be positioned with high accuracy. It has become.

  Then, as shown in FIGS. 1 and 2, in the mold configured as described above, the core material for forming the core is poured from the material flow inlet 21d and solidified, whereby the core material is obtained. A core that is bonded to the inner peripheral surface 1e of the cylinder liner 1 and integrated with the cylinder liner 1 is formed. The core formed in this way is removed from the lower mold 22 together with the upper mold 21 when the mold is opened after solidification, and then removed from the upper mold 21.

  2, the core can be formed for the cylinder block of the 2-cylinder engine. In this case, the upper die 21 inserted in the cylinder liner 1 arranged in parallel is used. For the tube portion 21A, the formation of the material pouring port 21d and the through hole 21c can be omitted.

  As shown in FIG. 1, the material poured from the material inlet 21d is, for example, a mixture of potassium chloride (melting point 770 ° C.) and artificial foundry sand at a weight ratio of 40:60, and then to 850 ° C. It can be made into a molten mixture by heating and melting potassium chloride.

Then, as shown in FIG. 3, the core 2 integrated with the cylinder liner 1 as described above is set in a casting mold of the cylinder block, and the cylinder block is cast.
First, the inner part 2a of the core 2 is inserted and attached to the core fixing part 12a of the movable mold 12, the movable mold 12, the slide molds 11 and 11, and the fixed mold 13 are clamped, and the cylinder block A cavity 14 having a shape is formed.
The core material solidified inside the through hole 21c shown in FIG. 1 is removed before being set in the casting mold of the cylinder block shown in FIG.

  Here, the core fixing portion 12a is a cylindrical bulging portion that protrudes toward the fixed die 13 in the movable die 12, and this core fixing portion 12a is located inside the cylinder liner 1 in the core 2. Is inserted into the cylindrical inner portion 2a.

Further, the inner portion 2a of the core 2 is formed by the spaces 23a and 23b of the cavity 23 shown in FIG. The inner portion 2a, which is removed later, functions as a liner support portion for positioning the cylinder liner 1 with respect to the core fixing portion 12a in the core 2.
With this function, positioning means by a separate member such as a mandrel for positioning the cylinder liner 1 with respect to the movable mold 12 (core fixing portion 12a) can be omitted.
Further, as shown in FIG. 3, the outer peripheral surface 12b of the core fixing portion 12a is in contact with the inner peripheral surface 2b of the inner portion 2a.

With the above configuration, as shown in FIG. 3, the core 2 is directly fixed to the core fixing portion 12 a which is a part of the movable mold 12, thereby positioning the core 2 with respect to the movable mold 12 with high accuracy. Can be done.
This also allows the cylinder liner 1 to be positioned with respect to the movable mold 12 with high accuracy, and high dimensional accuracy can be obtained in the cylinder block in the product state.
In addition, since a mandrel is not required unlike the prior art, it is not affected by mandrel-specific manufacturing errors or the like, and from this point, it is possible to obtain high dimensional accuracy in the cylinder block in the product state. .

Further, as shown in FIG. 3, in the cavity 14, outer portions 2 b and 2 b of the core 2 are disposed inside the slide molds 11 and 11. The outer portions 2b and 2b are formed by the space 23c of the cavity 23 shown in FIG.
The outer portions 2b and 2b are to be removed later. After the outer portions 2b and 2b are removed, they constitute a water jacket arranged around the cylinder liner 1 in the cylinder block. It functions as a water jacket forming part.
The outer portions 2b and 2b are formed outside the outer peripheral surface 1f of the cylinder liner 1 at a predetermined interval, and the position of a water jacket to be formed later is determined by the predetermined interval. Will be.

Then, as shown in FIG. 3, casting is performed by pouring molten metal into the cavity 14, the solidified product is demolded, and hot water is sprayed onto the core 2, whereby the outer portion 2 b. 2b and the inner part 2a are dissolved to remove them from the cylinder block.
Here, a water jacket is formed by removing the outer portions 2b and 2b.
Furthermore, by removing the inner portion 2a, the cylinder liner 1 is separated from the core 2, and the process of collecting the mandrel in the prior art is not required, and the cylinder block is manufactured with fewer processes. Can do.

  The core 2 to be removed and recovered is a mixture of an aqueous potassium chloride solution and artificial foundry sand. In this recovery, first, the mixture is subjected to an aqueous potassium chloride solution by a centrifuge, Separation into artificial foundry sand is followed by heating the potassium chloride aqueous solution to evaporate the water to obtain solid potassium chloride.

Further, as shown in FIG. 3, in the core 2, the inner portion 2 a and the outer portions 2 b and 2 b are continuously constituted by shoulder portions 2 c and 2 c, and the bottom surface of the shoulder portions 2 c and 2 c, By aligning the upper ends of the cavities 14, the formed cylinder block is an open deck type.
The shoulder portions 2c and 2c are formed by the space portions 23d and 23d of the cavity 23 as shown in FIG.

Next, a core for constituting a closed deck type cylinder block will be described with reference to FIGS.
As shown in FIGS. 4 and 5, with respect to the core for forming the closed deck type cylinder block, a wall for surrounding the cylindrical portion 22a of the lower mold 22 in the upper mold 21A for molding the core. Pin insertion holes 21 s and 21 s that penetrate in the radial direction of the cylinder portion 21 a of the upper mold 21 A are formed in a plurality of locations in the portion 21 n, and the pins 30 and 30 are inserted into the pin insertion holes 21 s and 21 s, respectively. The tip end portion of 30 is configured to abut on the upper portion of the cylindrical portion 22a of the lower mold 22.

  Then, as shown in FIG. 4, in the cavity 23, the material of the core 2 is missing at the portion where the pins 30 and 30 are present. As a result, as shown in FIG. Between 2b and shoulder part 2c * 2c, runner 2s * 2s through which a molten metal passes is formed.

  As shown in FIGS. 4 and 5, in this embodiment, in the upper end opening 22 g of the cylindrical portion 22 a of the lower mold 22, the depressions 22 s. 22s is provided so that the tip portions of the pins 30 and 30 are fitted into the recesses 22s and 22s so that the pins 30 and 30 are not displaced when the core material is poured.

The pins 30 and 30 are rod-shaped members that can be inserted / removed in order to form the runners 2s and 2s by constituting a missing portion of the core material. It is set as the shape suitable for comprising the cover part which block | closes the upper side open part.
For example, when the cross-sectional shape is a rectangle having a long width in the lateral direction as in the present embodiment, a cover portion corresponding to the long width can be configured.

As described above, as shown in FIG. 5 and FIG. 6, the pins 30 and 30 as rod-shaped members are inserted into the cavity 23 to form the missing portion of the core material, and the outside of the core 2. The runners 2s and 2s are formed in the portions 2b and 2b.
Then, as shown in FIG. 6, at the time of casting, the molten metal flows into the runners 2s and 2s, and after the outer portions 2b and 2b are removed, the lid portions respectively block the upper open portions of the water jacket. Thus, a closed deck type cylinder block can be configured.

  The technical scope of the present invention is not limited to the above-described embodiments, but broadly covers the entire scope of technical ideas that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It is.

Sectional drawing of the metal mold | die which shape | molds a core. The external view of the metal mold | die of FIG. 1 similarly. Sectional drawing of the metal mold | die which casts and casts the core integrated with the cylinder liner. Sectional drawing of the metal mold | die which shape | molds the core in the case of casting a closed deck type cylinder block. FIG. 5 is an external view of the mold in FIG. 4. Sectional drawing of the metal mold | die in the case of casting a closed deck type cylinder block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder liner 2 Core 2a Inner part 2b Outer part 11 Slide type 12 Movable type 12a Core fixed part 13 Fixed type 14 Cavity

Claims (5)

A cylindrical inner part, which is integrally formed on the inner peripheral surface of the cylinder liner and fixed to the core fixing part of the casting mold of the cylinder block;
An outer portion formed at a predetermined interval on the outer peripheral surface of the cylinder liner.
Core for forming water jacket for cylinder block. The core is molded by pouring a collapsible core material into a mold for core molding having a cavity that houses the cylinder liner, and is removed from the cylinder liner integrally.
The core for forming a water jacket for a cylinder block according to claim 1, wherein The cavity has a configuration in which the inner part and the outer part are continuously formed.
The core for forming a water jacket of a cylinder block according to claim 1 or 2, characterized in that Inserting a rod-shaped member into the cavity, constituting a missing portion of the core material, and forming a runner in the outer portion of the core,
The core for forming a water jacket for a cylinder block according to any one of claims 1 to 3, wherein the core is for forming a water jacket for the cylinder block. A cylindrical inner part, which is integrally formed on the inner peripheral surface of the cylinder liner and fixed to the core fixing part of the casting mold of the cylinder block;
A core for forming a water jacket of a cylinder block, having an outer portion formed at a predetermined interval outside the outer peripheral surface of the cylinder liner,
After casting the cylinder block by casting the inner portion fixed to the core fixing portion,
A method of casting a cylinder block, wherein a water jacket of the cylinder block is formed by dissolving and removing the core in water.

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