JP2004283862A - Method for manufacturing cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress knocking by surely preventing cast sand or molten metal from flowing into a hollow member to obtain a desired cooling performance, thereby correcting unbalanced thermal deformation due to variation of temperature distribution around a cylinder and reducing gas temperature inside the cylinder in the case of casting the hollow member inside a common wall formed between mutually adjacent cylinders. <P>SOLUTION: In the method for manufacturing a cylinder block 1, a plurality of cylinders 2 are arrayed adjacently to each other and cooling water channels 3 are formed along the arraying directions A of respective cylinders. In the mold for molding the cylinder block, in the positions 24, 25 corresponding to the inside of the common wall part 4 which is formed between the adjacent cylinders, a hollow member 5 with the edge made to be a closed cross section is preliminarily arranged in the manner that both ends 5a, 5b of the closed cross section edge is each situated in the cooling water channels 3a, 3b. Then, molten metal is poured in the mold with this hollow member 5 arranged and is cooled to cast the hollow member 5 inside the common wall part 4. After cooling, both ends 5a, 5b are removed which are situated in the cooling water channels 3a, 3b in the molded hollow member 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a so-called Siamese type cylinder block casting method in which adjacent cylinder walls are integrated and shared.
[0002]
[Prior art]
In a multi-cylinder engine, a cylinder block of a siamese type in which adjacent walls of each cylinder are thinned and integrated as a common wall in order to reduce the size of the engine is known. In this cylinder block, it is generally difficult to form a cooling passage because the common wall of adjacent cylinders is thin, and it is necessary to correct thermal deformation imbalance due to variations in temperature distribution around the cylinder and to reduce gas temperature in the cylinder. From the viewpoint of suppressing knocking, there is a demand to reduce the temperature of the cylinder periphery.
Against this background, Patent Literature 1 discloses a hollow member having both sides opened at a position corresponding to a common wall between adjacent cylinders of a mold for molding a cylinder block. There has been proposed a method of manufacturing a cylinder block in which a hollow member is disposed in a cooling water channel, a molten metal is poured into a mold in which the hollow member is disposed and cooled to cast the hollow member in a common wall portion.
[0003]
[Patent Document 1]
Patent Publication No. 2743131
[Problems to be solved by the invention]
A problem when casting the hollow member in the common wall portion is that molten metal or casting sand enters the hollow member and blocks it. For this reason, in Patent Literature 1, a pin that disappears due to the heat of the molten metal is inserted in advance into the opening located in the cooling water passage before pouring the molten metal, and the pin is vanished by the heat of the molten metal flowing into the mold. Thus, the hollow member is cast into the common wall while preventing the inflow of the casting sand from the opening into the hollow member.
However, when the pins are lost due to the heat of the molten metal, the pins can be reliably removed by maintaining the temperature of the molten metal at an appropriate temperature at which the pins can be removed, but before the pins are cooled and solidified, the pins are cooled. In the case of disappearance, there is a concern that the molten metal having fluidity flows into the hollow member from the opening and blocks the opening and the inside of the hollow member. In the case of the Siamese type cylinder block, the thickness of the common wall into which the hollow member is cast is small, and it is difficult to sufficiently secure the area of the opening and the volume of the hollow member. Therefore, the molten metal flows into the hollow member. If those areas and volumes are reduced, it becomes difficult to obtain desired cooling performance.
The present invention, when casting a hollow member in a common wall portion, reliably prevents the inflow of molding sand or molten metal into the hollow member and obtains a desired cooling performance, so that the temperature distribution of the cylinder peripheral portion varies. It is an object of the present invention to provide a method of manufacturing a cylinder block capable of correcting imbalance of thermal deformation due to heat and reducing knocking by reducing gas temperature in a cylinder.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, in the method of manufacturing a cylinder block according to the present invention, in which a plurality of cylinders arranged adjacent to each other and a cooling water channel are formed along the arrangement direction of the cylinders, In a position corresponding to the common wall between the adjacent cylinders of the mold for molding the hollow member whose edge is a closed section, both ends of the edge of the closed section are located in the cooling water channel, respectively. The hollow member is cast in the common wall portion by pouring the molten metal into the mold in which the hollow member is disposed and cooling, and both ends of the cast hollow member located in the cooling water channel are removed after cooling. It is characterized by:
For this reason, the edge of the hollow member remains a closed section when the molten metal is poured into the mold, and after being cast into the common wall, both sides of the closed section edge located in the cooling water channel are removed. As a result, the cooling water passage is opened.
[0006]
When the cylinder block is manufactured by the die-casting method, the mold in which the hollow member is provided is a mold in which the cooling water passage is formed on both sides of the cylinder, and the common wall between the adjacent cylinders in the mold in which the cooling water passage is formed. A step corresponding to the inside of the cooling water passage after molding is formed in a portion corresponding to the inside of the part, a hollow member is mounted on this step, a molten metal is poured and cooled, and the hollow member is cast into a common wall portion, and the cooling water passage is formed. After removing the mold that forms, a cutting tool is inserted into the formed cooling channel to remove both ends of the cast hollow member located in the cooling channel. By adopting such a process, the edge of the hollow member remains in the closed section when the molten metal is injected into the mold, and is closed in the cooling water channel after being cast into the common wall. Are removed and open to the cooling water channel. Therefore, in the case where a gap is formed between the step portion of the mold and the hollow member in consideration of the mold releasability, it is possible to prevent casting sand or molten metal from flowing into the hollow member.
[0007]
When the cylinder block is manufactured by the core manufacturing method, the mold in which the hollow member is disposed is formed with cooling water passages on both sides, and is a core formed by molding sand or a core that disappears due to heat of the molten metal of the cylinder. Both ends of the hollow member are buried in portions corresponding to the common wall between adjacent cylinders of the core, and the hollow member is cast into the common wall by pouring the molten metal and cooling, and in a cooling water passage formed after cooling. A cutting tool is inserted into the hollow member to remove both ends of the cast hollow member located in the cooling water channel.
By adopting such a manufacturing method, the edge of the hollow member remains in the closed section when the molten metal is poured into the mold, and the edge of the closed section located in the cooling water channel after being cast into the common wall. Both sides of the section are removed and open to the cooling channel.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes four cylinders 2, 2,... Arranged directly adjacent to each other and an arrangement direction of these cylinders 2, 2,. 2 shows a cylinder block in which a cooling water passage 3 is formed along. The cooling water passage 3 is formed continuously along the outer shape of each cylinder 2. In the cylinder block 1, common wall portions 4, 4, 4 are formed between cylinders adjacent to each other in a direction orthogonal to the arrangement direction A indicated by the arrow B (hereinafter referred to as "orthogonal direction B"). I have. A hollow member 5 is cast in the interior of each common wall portion 4 in the orthogonal direction B.
[0009]
FIG. 2 shows an example of the shape of each hollow member 5. The hollow member 5 shown in FIG. 2 is in the form of a metal bag, and all of its edges 5a, 5b, 5c, 5d are closed by welding or the like. The width W1 of the hollow member 5 is formed wider than the width W of the common wall portion 4, and both ends 5a, 5b protrude so as to be located in the cooling water passages 3a, 3b located in the orthogonal direction B. .
[0010]
FIG. 4 shows a hollow member 10 formed of a pipe member. The hollow member 10 is obtained by arranging a plurality of pipe members in the axial direction of a cylinder indicated by an arrow C and integrating them by welding or the like. Both ends 10a and 10b of each pipe, which are edges of the hollow member 10, are closed with a metal made of hot water, and have a closed cross-sectional structure. Instead of closing both ends 10a and 10b with a metal made of hot water, both ends of each pipe member may be closed by crushing or hitting. The length W2 in the axial direction of the pipe member, which is the width of the hollow member 10, is longer than the width W1 of the common wall 4, and both ends 10a, 10b protrude so as to be located in the cooling water passages 3a, 3b during casting. Have been.
[0011]
As shown in FIG. 3, each of the hollow members 5, 10 protrudes into the cooling water passages 3a, 3b in a state where both ends 5a, 5b and both ends 10a, 10b have a closed cross section and are closed during casting. In rare cases, after cooling, both ends 5a and 5b and both ends 10a and 10b of the closed cross section are cut off by a cutting tool 6 such as a drill or a reamer, so that an opening communicating with the cooling water passages 3a and 3b is formed.
[0012]
Next, a method for manufacturing the cylinder block 1 will be described. In this embodiment, the die casting method and the core method will be described in comparison with general methods.
(Die casting method)
In FIG. 5, (a) shows steps of a cylinder block by a general die-casting method, and (b) shows steps of a cylinder block by a die-casting method according to the present invention. In FIG. 5A, first, a mold set for assembling a plurality of molds processed into a desired shape is performed, and a metal melt used for a cylinder block is poured into the assembled mold. After pouring, the molten metal is cooled in a state where it is assembled into a mold, and after cooling and the molten metal is solidified, the mold is removed to remove the gate and burrs. Then, the molded thin cylinder block is cleaned, and various cutting operations such as screw hole processing for fastening a cylinder head and a crankcase are performed. After this processing, cleaning is performed to remove shavings and the like. .
[0013]
In this embodiment, as shown in FIG. 5B, the hollow member 5 is formed in advance, and the hollow member 5 is placed in the left and right dies 20, 21 of the lower die 27 as shown in FIG. It is mounted on the upper mold 22 set on the above. The upper die 22 is provided with a projection 23 for continuously forming the cooling water passage 3 along the periphery of the cylinder 2 after cooling, and the hollow member 5 is mounted on portions 24 and 25 of the projection 23 corresponding to a common wall. Steps 24a and 25a are formed. The steps 24a, 25a extend in the axial direction C of the cylinder, and the steps 24a, 25a also extend in the same direction. The width W3 of the step portion 24a and the step portion 25a is formed to be somewhat wider than the width W1 of the hollow member 5, so that the hollow member 5 can be separated well from the hollow member 5 during die cutting. That is, the steps 24a, 25a formed on the projections 24, 25 forming the cooling water channels 3a, 3b are formed so as to reach the inside of the cooling water channels 3a, 3b after molding, and the steps 24a, 25a are formed. The hollow member 5 is mounted. The steps so far are the first characteristic steps of the present invention.
[0014]
A mold setting for assembling the hollow member 5 is performed, and as in FIG. 5A, a molten metal is poured, and the molten metal is cooled in a state where the molten metal is assembled into the mold, and the hollow member 5 is cast into the common wall portion 4. After cooling and solidification of the molten metal, the mold is removed and the gate and burrs are removed. Then, the molded thin block is washed, and the process is started. In the present embodiment, as shown in FIG. 7A, both ends 5a and 5b of the closed cross section cast into the common wall portion 4 and projecting into the cooling water passages 3a and 3b in this processing step. It is removed by a cutting tool 6, and after this processing, cleaning is performed to remove shavings and the like.
[0015]
As described above, by setting the edge of the hollow member 5 to be cast into the common wall portion 4 in a closed state and setting it in the upper mold 22 in advance and injecting the molten metal, the casting sand or the molten metal flows into the hollow member 5 during casting. Can be prevented. After the molten metal is cooled, both ends 5a and 5b protruding into the cooling water passages 3a and 3b are cut by the cutting tool 6, so that the cooling water passages 3a and 3b and the hollow member 5 are formed as shown in FIG. Can be formed facing the inside of the cooling water passage, so that the cooling water in the cooling water passages 3a and 3b is introduced into the hollow member 5, so that the hollow member 5 is cast. Each common wall 4 can be cooled. In addition, since casting sand or molten metal does not flow into the hollow member 5, a desired cooling performance can be obtained.
(Core production method)
In FIG. 9, (a) shows a cylinder block process by a general core manufacturing method, and (b) shows a cylinder block process by a core manufacturing method according to the present invention. In FIG. 9 (a), first, a core forming the outer shape of the cooling water channel is formed by casting sand, a mold is set by assembling a mold and a core, and a molten metal of a metal used for a cylinder block is injected into the assembled mold. I do. After the casting, the molten metal is cooled in a state where it is assembled into a mold, and after the metal is cooled and solidified in a molten state, the mold and the core are removed. Then, the molded cylinder block is cleaned, and various cuts such as screw hole processing for fastening a cylinder head, a crankcase, and the like are performed. After this processing, cleaning is performed to remove shavings and the like.
[0016]
In this embodiment, as shown in FIG. 9B, hollow members 5 and 10 as shown in FIGS. 2 and 4 are prepared in advance. Next, as shown in FIG. 8, the hollow members 5 and 10 are set by embedding both ends of the hollow members in portions 31, 32 and 33 of the core 30 corresponding to the adjacent common wall portion 4, respectively. Perform child blow. In this embodiment, the hollow member 10 is set on the core 30. The steps up to this point are the first characteristic steps of this embodiment. Next, a mold (not shown) and the core 30 are set, and in the same manner as in the step shown in FIG. 9A, a molten metal of a metal used for the cylinder block is poured into the assembled mold, and the molten metal is cooled in a state assembled in the mold. I do. After cooling and solidification of the molten metal, the mold and the core are removed, sand removal is performed, and gates and burrs are removed. Then, the molded cylinder block is cleaned, and a processing step is started.
[0017]
In the present embodiment, in this processing step, as shown in FIG. 10A, both ends 10a and 10b of the closed cross section cast into the common wall portion 4 and projecting into the cooling water passages 3a and 3b are formed. It is removed by a cutting tool 6, and after this processing, cleaning is performed to remove shavings and the like.
[0018]
As described above, the hollow member 10 to be cast into the common wall portion 4 is attached to the core 30 in a closed state, and is set in the mold in advance to inject the molten metal. 10 can be prevented from flowing. After the molten metal is cooled, both ends 10a and 10b projecting into the cooling water passages 3a and 3b are cut by the cutting tool 6, so that the cooling water passages 3a and 3b and the hollow member 10 are formed as shown in FIG. Can be formed facing each cooling water channel, and the cooling water in the cooling water channel is introduced into the hollow member 10, so that each common wall portion 4 can be cooled. In addition, since casting sand and molten metal do not flow into the hollow member 10 during casting, desired cooling performance can be obtained.
[0019]
When the hollow members 5 and 10 are cast into the common wall using the above-described manufacturing method, a desired cooling performance can be obtained, so that a variation in the temperature distribution around the cylinder can be suppressed, and the imbalance in thermal deformation can be reduced. Can be corrected. Further, since a reduction in the gas temperature in the cylinder 2 during combustion can be expected, occurrence of knocking can be suppressed, and knock resistance is improved.
[0020]
In the present embodiment, the core 30 is formed of cast sand. However, for example, the core may be formed of a resin material that disappears by the heat of the molten metal, and the hollow members 5 and 10 may be set on the core and used. Generally, the resin core is strong in strength, but the core in cast sand may have insufficient strength in the orthogonal direction B because the cylinder portion is hollow. In such a case, as shown by a broken-line square in FIG. 9 (a), a core reinforcing plate is created, and the created core reinforcing plate is set on the core to perform the core blowing step. There is also. Therefore, the strength of the core 30 can be increased by using the hollow members 5 and 10 as the core reinforcing plate.
[0021]
【The invention's effect】
According to the present invention, the edge of the hollow member remains closed when the molten metal is poured into the mold, and is closed in the cooling water channel after being cast into the common wall of the adjacent cylinders. Since the opening is opened to the cooling water channel by removing both sides of the portion, even when the hollow member is cast in the common wall portion, it is possible to reliably prevent the inflow of molding sand or molten metal into the hollow member, and Cooling performance is easily obtained. For this reason, it is possible to correct the imbalance of thermal deformation due to the variation of the temperature distribution in the cylinder peripheral portion, and to suppress the knocking by reducing the gas temperature in the cylinder.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a cylinder block manufactured by a manufacturing method of the present invention.
FIG. 2 is a front view showing an embodiment of a hollow member cast into a cylinder block.
FIG. 3 is an enlarged view of the vicinity of a common wall portion into which a hollow member is cast.
FIG. 4 is a front view showing another form of the hollow member cast into the cylinder block.
FIG. 5A is a process diagram showing an example of a manufacturing process by a general die-casting method, and FIG. 5B is a process diagram showing an example of a manufacturing process by a die-casting method according to the present embodiment.
FIG. 6 is an enlarged sectional view showing a state in which the hollow member is set on an upper mold.
FIG. 7A is an enlarged cross-sectional view showing a state of a cast hollow member and a cutting step for both ends of the cooling water channel, and FIG. 7B is processed in the cutting step shown in FIG. It is an expanded sectional view which shows the cooling state of the common wall part by the hollow member which fell.
FIG. 8 is an enlarged perspective view showing a core on which a hollow member is mounted.
9A is a process diagram showing an example of a manufacturing process by a general core manufacturing method, and FIG. 9B is a process diagram showing an example of a manufacturing process by a core manufacturing method according to the present invention.
10A is an enlarged cross-sectional view showing a state of a cast hollow member, and a cutting process for both ends of the hollow member in a cooling water channel, and FIG. It is an expanded sectional view which shows the cooling state of the common wall part by the hollow member which fell.
[Explanation of symbols]
1 Cylinder block 2 ... A plurality of cylinders 3, 3a, 3b Cooling water channel 4 ... Common wall 5,10 between cylinders Hollow members 5a, 5b, 10a, 10b Both ends 6 Cutting tool 22 Upper mold (mold)
24, 25 Positions 24a, 25a corresponding to common wall portion Step 30 Core (mold to be molded)
31, 32, 33 Position A corresponding to the common wall portion Arrangement direction of cylinders

Claims (3)

A method of manufacturing a cylinder block in which a plurality of cylinders arranged adjacent to each other and a cooling water passage are formed along the arrangement direction of the cylinders,
At the position corresponding to the common wall between the adjacent cylinders of the mold for molding the cylinder block, a hollow member having an edge of a closed cross section is provided. Pre-arranged to be located in each,
The hollow member is cast into the common wall by pouring the molten metal into the mold in which the hollow member is arranged and cooling the molten metal,
A method of manufacturing a cylinder block, comprising removing both ends of the cast hollow member located in the cooling water channel after cooling. The method for manufacturing a cylinder block according to claim 1,
When manufacturing the cylinder block by a die casting method,
The mold in which the hollow member is disposed is a mold in which the cooling water passage is formed on both sides of the cylinder. In the mold in which the cooling water passage is formed, a portion corresponding to a common wall portion between the adjacent cylinders is formed. Forming a step that reaches the inside of the later cooling water channel, casting the hollow member into the common wall by mounting the hollow member on this step and pouring and cooling the molten metal,
A method of manufacturing a cylinder block, comprising: removing a mold forming the cooling water channel, and removing both ends of the cast hollow member located in the cooling water channel by inserting a cutting tool into the cooling water channel. . The method for manufacturing a cylinder block according to claim 1,
When manufacturing the cylinder block by a core manufacturing method,
The mold in which the hollow member is disposed is a core in which the cooling water passage is formed on both sides of the cylinder, and a core that is formed by casting sand or a core that disappears due to heat of the molten metal. In a portion corresponding to a common wall portion between cylinders, both ends of the hollow member are embedded, and the hollow member is cast into the common wall portion by pouring and cooling a molten metal,
A method of manufacturing a cylinder block, comprising: after cooling, inserting a cutting tool into the cooling water passage to remove both ends of the cast hollow member located in the cooling water passage.

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