JP2016107326A - Structure of mold for casting long casts and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a mold for casting a plurality of long casts and a manufacturing method for the same capable of improving productivity while preventing occurrence of variation in quality.SOLUTION: A structure of a mold for casting long casts comprises a plurality of molds 11 provided with vertical runners 15 in mating surfaces 13 of a pair of vertically positioned split dies 12 are integrated with the split dies 12 arranged back-to-back to position respective mating surfaces 13 in parallel. Horizontal runners 19 communicating lower parts of both vertical runners of a plurality of molds 11 with each other are formed. A sprue cap 18 is provided at the top edge of one of vertical runners 15 in the plurality of molds 11. The lower a position in each of the vertical runners 15 in the plurality of molds 11 is, the smaller a passage cross sectional area is.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mold structure for casting a long cast product and a manufacturing method thereof.

  Conventionally, there have been various proposals for a mold structure for obtaining a long cast product such as an engine camshaft. For example, Patent Document 1 discloses that a plurality of shell molds having camshaft cavities extending in the vertical direction and having vertical mating surfaces are accommodated in a cast box, and a gate is provided in each mold. In Patent Document 2, a single mold is provided with a plurality of camshaft cavities extending in the horizontal direction at intervals in the vertical direction, and a single vertical runway leading to the plurality of cavities. It is disclosed that a plurality of gates are provided to take a plurality.

Japanese Utility Model Publication No. 62-61141 JP 2014-69204 A

  In the mold structure disclosed in Patent Document 1, only one long cast product can be obtained from one mold, and it is necessary to pour individual cavities from separate gates, thereby increasing productivity. difficult.

  According to the mold structure disclosed in Patent Document 2, although the productivity can be improved to some extent by taking a plurality of pieces, in the cavity arranged on the upper side and the cavity arranged on the lower side, the vertical hot water is caused by the difference in head pressure. Since the flow rate or pressure of the molten metal flowing in from the road is different, the quality tends to vary. Further, from the viewpoint of improving productivity, it is conceivable that a plurality of the above-mentioned molds are arranged side by side and poured into each mold. However, it is necessary to provide a pouring gate in each mold, and the productivity is not necessarily increased.

  On the other hand, a plurality of molds having a plurality of cavities extending in parallel in the horizontal direction are stacked to form one horizontal runway that leads to the plurality of cavities in each mold, and the horizontal molds on the upper and lower molds. It is conceivable to provide a through hole for communicating the road, that is, to form one vertical runway by matching each through hole.

  However, in the case of such a gate design, although productivity is improved, it is difficult to solve the quality variation problem due to the difference in head pressure.

  That is, in order to form the vertical runners, through holes for the vertical runners are formed in each of the pair of split molds constituting each mold, and the through holes of the upper and lower molds are formed at the time of stacking. At the same time, the lower split mold through hole of the lowermost mold is closed with a stopper, while a gate is provided in the upper split mold through hole of the uppermost mold. Thus, in order to improve productivity, it is possible to standardize the mold, that is, to use it for both the upper stage and the lower stage in the same mold, instead of manufacturing the mold at each stage with a separate mold. It is necessary to produce a mold that can be used.

  In that case, since the diameter of the said through-hole is the same in all the obtained molds, the vertical runway formed with the through-hole becomes the same diameter from the uppermost mold to the lowermost mold. As a result, in the upper mold and the lower mold, the difference in the head pressure appears as a difference in the flow rate of the molten metal flowing into the cavity as it is, and the above-described quality variation is likely to occur.

  In casting, a backup material is laid on the bottom of the casting box, a plurality of molds stacked thereon are placed, and the backup material is filled around the same. Then, while the load is applied to the lower mold from the upper mold, only the load of the backup material filled thereon is applied to the upper mold. As a result, in the upper and lower molds, the load applied to the mating surfaces of the split molds is different, so the amount of mold tension is different, which means that casting burrs are likely to occur in the upper mold, and long casting It also causes the product to bend.

  Therefore, the present invention suppresses the occurrence of variations in the quality of the obtained cast product as much as possible while improving productivity by adopting a plurality of molds when obtaining a long cast product.

  In order to solve the above-mentioned problem, the present invention does not stack a plurality of casting molds vertically with the mating surfaces being horizontal, but with the mating surfaces of the respective molds being vertical and these mating surfaces being parallel to each other. It was made to unite side by side so that it might become.

That is, the mold structure for casting the long cast product disclosed herein includes a plurality of molds formed by combining a pair of shell-shaped split molds,
Each of the molds has a vertical mating surface of the split mold, and a plurality of cavities extending in parallel in the lateral direction with a vertical interval for taking a plurality of the cast products, and the plurality of cavities. One longitudinal runway extending in the vertical direction at one end side in the cavity longitudinal direction for guiding the molten metal,
The plurality of molds are combined with the split molds back to back so that the mating surfaces are parallel to each other,
A horizontal runway that connects the lower ends of the vertical runners of the plurality of molds is formed,
A gate is provided at the upper end of any one of the plurality of molds,
The longitudinal runner of each of the plurality of molds is characterized in that the cross-sectional area of the passage becomes smaller as it goes downward.

  According to such a mold structure, when molten metal is poured from the gate, the molten metal flows into each cavity of the mold in which the gate is provided in the vertical runway. Further, the molten metal flows from the lower end of the vertical runner through the horizontal runner to the vertical runner of another mold, and the molten metal flows from the vertical runner into each cavity of the other mold.

  Thus, according to the present invention, the configuration is adopted in which the mating surfaces of each of the plurality of molds are arranged vertically and the vertical runners are provided in each mold. It is possible to form a vertical runner considering the head pressure, that is, a vertical runner having a passage cross-sectional area that decreases toward the bottom. As a result, even if the head pressure itself becomes larger in the cavity located at the lower side, in the vertical runway provided with the above-described pouring gate, the passage resistance received by the molten metal becomes larger as it goes down, so that It becomes easy to make the flow rate of the melt flowing in substantially the same.

  Further, as described above, the plurality of molds are combined such that each mating surface is vertical and the mating surfaces are parallel to each other. Accordingly, when the plurality of combined molds are accommodated in a cast box and packed with a backup material, the mold tension of each mold is received by the side walls facing the direction perpendicular to the mating surface of the cast box, The mold tension is reduced in the same way. Therefore, it is possible to avoid variations in the quality of the long cast product obtained by each mold.

  In addition, since the vertical runners are provided in each of the plurality of molds and the vertical runners are communicated with the horizontal runners, the plurality of molds can be used in spite of changing the cross-sectional area of the vertical runners as described above. These molds can be formed with a common mold.

  In a preferred embodiment, three or more of the molds are combined, and the gate is provided in the vertical runner of the mold disposed on the center side. Thereby, since the molten metal flows from the vertical runner of the mold on the center side through the horizontal runner to the vertical runner of the mold on both ends, the distribution of the molten metal to each mold is improved, and each mold is obtained. Variations in the quality of the long cast product are suppressed.

  In a preferred embodiment, the weir connecting the vertical runner and the cavity is an upward runway from the vertical runner toward the cavity. As a result, turbulent flow is avoided when the molten metal flows into the cavity from the vertical runner, and the occurrence of casting defects is suppressed.

  In a preferred embodiment, the axis extending in the lateral direction of the cavity is inclined at an angle of 1 to 3 degrees with respect to the horizontal line so that the position gradually increases from one end to the other end on the vertical runner side. It has been. Thereby, since it becomes easy to avoid that the flow velocity of the molten metal which flows from one end of a cavity to the other end changes on the way, generation | occurrence | production of a casting defect is suppressed.

  In a preferred embodiment, each of the pair of split molds constituting the mold has a through hole for forming the side runner, and the split mold through holes that are back to back are combined. The side runners are formed by fitting plugs into the split through holes located at both ends.

  In a preferred embodiment, each of the plurality of molds is formed such that the upper end of the vertical runner is open, and a gate is provided at the upper end of the vertical runner of any of the plurality of molds. The opening at the upper end of the vertical runner of the other mold is closed with a stopper.

  In a preferred embodiment, each of the plurality of molds includes a lift on the other end side in the longitudinal direction of the cavity, and the at least one set of split molds that are back-to-back are adjacent to each other when they are back-to-back. A through-hole is formed so as to communicate the lifts of each other. Thereby, the molten metal flows into the through-hole, and a crossing portion that connects the adjacent raised portions is formed. That is, the two long cast products are connected to each other at the crossing portion (the individual long cast products can be prevented from being separated). Therefore, since the two long cast products can be hung by hanging the transition portion on the hanger of the shot blasting device, the sand dropping operation after casting becomes easy.

Moreover, the manufacturing method of the mold structure for casting the long cast product disclosed herein is:
By combining a pair of shell-shaped split molds, a plurality of cavities parallel to each other for taking a plurality of the cast products, and one end side in the longitudinal direction of the cavity for guiding the molten metal to the plurality of cavities Forming a mold having a first runner extending in the direction of alignment and having a passage cross-sectional area that decreases from one end to the other;
A step of stacking and combining a plurality of the molds such that the mating surfaces of the split molds lie down;
The combined mold obtained by the above stacking has a plurality of cavities of the respective molds extending in the horizontal direction at intervals, and the cross-sectional area of the passage becomes smaller as the first runner extends in the vertical direction and goes downward. A process of rotating to become a vertical runway;
And a step of providing a gate at the upper end of the vertical runner of any one of the above-mentioned combined molds.

In the split mold, a through hole is formed for communicating the other ends of the first runner of the mold that are adjacent to each other by the stacking.
In the step of stacking the molds, the split-type through holes that are back-to-back are aligned with each other, and the lower split-type through hole in the lowermost mold and the upper split mold through-hole in the uppermost mold are plugged. By closing, a second runner that connects the first runners of the plurality of molds is formed,
In the step of rotating the mold group, the combined mold is rotated so that the second runner is a horizontal runner that communicates the lower ends of the vertical runners of the plurality of molds.

  With this manufacturing method, a mold structure for casting the above-described long cast product can be obtained.

  According to the present invention, a configuration in which the mating surfaces of each of the plurality of molds are arranged vertically and a vertical runner is provided in each mold is adopted, and the cross-sectional area of the passage is reduced as the vertical runner is moved downward. Because it is possible to suppress variations in the quality of the long cast products obtained from the cavities arranged vertically, and to suppress the mold tension of each mold in the same way, the long cast products obtained from each mold It is possible to avoid variations in the quality of the product, and it is possible to form a plurality of molds with a common mold in spite of changing the passage cross-sectional area of the vertical runner as described above, which is advantageous for cost reduction. become.

The perspective view which shows the casting (pouring plan) obtained with the casting_mold | template structure which concerns on embodiment of this invention. Sectional drawing which shows the state which put the said casting_mold | template structure in the cast box. The side view of the said mold structure. The side view which shows the split surface of a split mold. The cross-sectional view which shows a split-type lift formation part. The figure which shows the stacking process of a casting_mold | template. The front view which shows the united casting_mold | template obtained by stacking. Sectional drawing which shows a crossing hot spring. The front view which shows the state which rotated the union mold after stacking 90 degree | times. The side view which shows the split surface of the split type | mold which concerns on another embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

  The present embodiment is an example in which a camshaft of an engine is cast as a long cast product. FIG. 1 shows a casting obtained by mold release after casting by the mold structure according to the present embodiment. In the figure, 1 is a camshaft portion, 2 is a gate portion, 3 is a vertical runner portion extending in the vertical direction, 4 is a horizontal runner portion extending in the horizontal direction, and 5 is a lifting portion. A number of camshaft portions 1 are connected by runners 3 and 4. This will be specifically described below.

  The casting includes a plurality of vertical runners 3, and the lower ends of the vertical runners 3 are connected by a horizontal runner 4. A gate (receiving port) 2 is provided at the upper end of one of the plurality of vertical runners 3, and no gate is provided at the upper end of the other vertical runners 3. A plurality of camshaft portions 1 extend from each vertical runway 3 in parallel in the horizontal direction with an interval in the vertical direction. A lifting portion 5 is provided at the tip of each camshaft portion 1, and the lifting portions 5 of two camshaft portions 1 adjacent in the lateral direction are connected by a crossover portion 6. In this embodiment, the crossover part 6 is provided so that the two camshaft parts 1 may become 1 set.

<Mold structure>
As shown in FIG. 2, the mold structure 10 according to this embodiment is formed by combining a plurality of molds 11. Each mold 11 is formed by combining a pair of shell-shaped split molds 12, and the mating surface 13 of the split mold 12 is vertical. The plurality of molds 11 are aligned and united so that the mating surfaces 13 are parallel to each other, that is, the split molds 12 are back to back.

  As shown in FIG. 3, each mold 11 has a plurality of product cavities 14 extending in parallel in the lateral direction with a vertical interval for taking a plurality of camshafts, and for introducing the molten metal to the plurality of cavities 14. One longitudinal runner 15 extending in the vertical direction is provided on one end side in the cavity longitudinal direction. A lift 16 is provided at the other end in the longitudinal direction of each cavity 14. The vertical runway 15 has a smaller passage cross-sectional area as it goes downward. A weir 17 connecting the vertical runway 15 and each cavity 14 is an upward runway from the vertical runway 15 toward the cavity 14. The axis of each cavity 14 is inclined with respect to the horizontal line so that the position gradually increases from the base end on the vertical runner 15 side toward the tip.

  A spout cup 18 is provided at the upper end of the vertical runner 15 of the mold 11 arranged on the center side among the plurality of molds 11 arranged side by side, and the upper ends of the vertical runners 15 of the other molds 11 are closed with plugs. It is. The lower ends of the vertical runners 15 of each of the plurality of molds 11 communicate with each other through a horizontal runner 19.

  The gate system of the mold structure 10 can be understood more easily by referring to FIG.

  As shown in FIG. 4, the split mold 12 has a plurality of cavity forming portions 21 arranged in parallel to form a cavity 14 and one end side in the longitudinal direction of the cavity forming portion 21. A vertical runner forming part 22 for forming the vertical runner 15 extending in the direction in which the cavity forming parts 21 are arranged is provided. A lift forming portion 23 is provided at the other end in the longitudinal direction of each cavity forming portion 21. The vertical runner forming part 22 and each cavity forming part 21 are provided with a weir forming part 24 for forming the weir 17 that has become the above-described rising runway. The weir forming part 24 is bowed so that the flow of the molten metal in the weir 17 is not disturbed. The angle θ formed by the axis A and the horizontal line H of each cavity forming portion 21 is 1 degree or more and 3 degrees or less.

  One end side of the vertical runner forming part 22 (the side where the passage area of the vertical runner 15 is increased) is an enlarged part 25 for fitting the tap cup 18 or a stopper, and is open to the end face of the split mold 12. . Further, a through hole 26 for forming the horizontal runner 19 is provided on the other end side of the vertical runner forming portion 22. Further, in the split mold 12 shown in FIG. 4, a through hole 27 for forming a crossing hot water channel that becomes the crossover part 6 shown in FIG.

  The through holes 26 for forming the side runner 19 are provided in all the split molds 12 constituting the mold structure 10, and when the mold structure 10 is formed, the split molds positioned at both ends of the mold structure 10. Only the twelve through holes 26 are plugged. Therefore, the through hole 26 is formed when the split mold 12 is formed by a shell mold.

  On the other hand, as shown in FIG. 1, the crossover portion 6 does not connect all the camshaft portions 1 arranged in the lateral direction, but connects two adjacent camshaft portions 1 so as to form a set. Is. Therefore, it is not necessary to provide the through holes 27 for forming the transitional hot water passages in all of the split molds 12 constituting the mold structure 10, and it is sufficient to provide them in some of the split molds 12. Therefore, in the present embodiment, the through hole 27 is formed in the necessary split mold 12 after the split mold 12 is formed by a shell mold.

  The pair of split molds 12 forming the mold 11 are not necessarily the same shape or symmetrical. In the case of casting the camshaft as in the present embodiment, the shape of the pair of split molds 12 is different, but for convenience, one of the split molds 12 is formed. Only the split surface of the split mold 12 is shown in FIG.

<Method for producing mold structure>
Hereinafter, a method for manufacturing the mold structure 10 will be described.

-Production of split mold-
The split mold 12 is formed by a shell mold method. As illustrated in FIG. 4, the split mold 12 includes a plurality of cavity forming portions 21, vertical runner forming portions 22, lift forming portions 23, weir forming portions 24, and through holes for horizontal runners depending on the molding. 26 is formed.

  As shown in FIG. 4, in the peripheral part of the split mold 12, there is a plug for closing the upper end opening of the vertical runner 15 without the gate cup 18, and the horizontal runner of the split mold 12 at both ends of the mold structure 10. A plug forming portion 28 for obtaining a plug for closing the through hole 26 is formed. The plug forming part 28 is formed by providing a thin part in an annular shape. By punching out the portion surrounded by the thin wall portion (by breaking the thin wall portion), the necessary number of plugs whose peripheral surfaces are tapered are obtained.

  As shown in FIG. 5, a portion 23 a for forming the through hole 27 of the lift forming portion 23 of the split mold 12 is made thin. Thus, for the split mold 12 on which the transition portion 6 is to be formed, the through hole 27 is formed by punching out the thinned portion 23a of the lift forming portion 23 with a punch. In the example of the mold structure 10 shown in FIG. 2, the through holes 27 are formed in all the lift forming portions 23 of the split mold 12 that are back-to-back with the mold 11 on both ends and the mold 11 on the inner side.

  All the split molds 12 that constitute the mold structure 10 form the respective cavity forming portions 21, vertical runner forming portions 22, lift forming portions 23, weir forming portions 24 and through holes 26, and through holes 27. The portions 23a are provided at positions corresponding to each other.

-Mold matching (formation of mold)-
A pair of split molds 12 forming one mold 11 are joined together at their mating surfaces 13. At that time, for the split molds 12 positioned at both ends of the mold structure 10, the through holes 26 are closed by plugs 29 obtained by punching the plug forming portions 28 as shown in FIG. 6. When a pair of split molds 12 are joined, the first runner that forms the vertical runner 15 is formed in the mold 11 by the vertical runner forming portions 22 facing each other.

-Stacking-
As shown in FIG. 6, a plurality of molds 11 obtained by mold matching are stacked side by side. At that time, the molds 11 adjacent to each other are joined together. Thereby, the united template 31 in which the plurality of templates 11 shown in FIG. 7 are combined is obtained. When the through holes 26 at the corresponding positions of the molds 11 match each other, a second runner that becomes the side runner 19 is formed. As shown in FIG. 8, in the two back-to-back split molds 12 in which the through-holes 27 are formed, the through-holes 32 are formed by matching the through-holes 27 with each other.

-Rotation of coalescing mold, installation of gate cup and stopper-
As shown in FIG. 7, the combined mold 31 obtained by stacking is rotated 90 degrees so that the first runner of each mold 11 becomes the vertical runner 15 and the second runner becomes the horizontal runner. To do. As shown in FIG. 9, a gate cup 18 is attached to the upper end opening of the vertical runner 15 of one mold 11 located on the center side of the combined mold 31, and the upper end opening of the vertical runner 15 of the other mold 11 is connected to the plug. The plug 33 obtained by punching the molding portion 28 is closed. As described above, the mold structure 10 is obtained.

<Casting>
As shown in FIG. 2, a backup material (steel particles) 36 is spread on the bottom of the casting box 35, the mold structure 10 is placed thereon, and further, only the upper end portion of the gate cup 18 is exposed. The back-up material 36 is filled around 10. The cast box 35 is vibrated with a shaker to tighten the backup material, and then the molten metal is poured from the gate cup 18.

  Since the longitudinal cross-sectional area of the vertical runway 15 following the gate cup 18 decreases as it goes downward, even if the head pressure itself of the molten metal increases as the cavity 14 located on the lower side, Since the passage resistance received by the molten metal increases as it goes downward, the flow rates of the molten metal flowing into the cavities 14 arranged vertically can be made substantially the same. That is, it is possible to avoid the turbulent flow due to the high flow rate of the molten metal in the lower cavity 14. Therefore, variations in the quality of the camshaft obtained by the cavities 14 arranged vertically are avoided.

  Further, since the molten metal flows from the vertical runner 14 of the mold 11 on the center side of the mold structure 10 through the horizontal runner 19 to the vertical runner of the mold 11 on both ends, the distribution of the molten metal to each mold 11 is performed. Become good. Therefore, it is possible to avoid the camshaft quality from being varied between the molds.

  In addition, since the weir 17 is an upward runway from the vertical runway 15 toward the cavity 14, it is possible to avoid turbulent flow when the molten metal flows into the cavity 14 from the vertical runway 15. Is suppressed.

  In addition, since the axis of the cavity 14 is inclined upward from one end to the other end, the flow rate of the molten metal in the cavity 14 is prevented from changing in the middle, and the occurrence of casting defects is suppressed.

  Further, in the casting structure 10 where the mold tension tends to be a problem, since the mating surfaces of the casting molds 11 are vertical and parallel, the static pressure of the molten metal or the transformation of the solidified metal is caused. The expansion pressure is received by the side wall of the casting box 35 via the backup material 36 packed on both sides in the direction orthogonal to the mating surface, and the side walls serve as a backup to ensure the mold tension of each mold 11. Can be suppressed.

<Post-processing>
After the molten metal injected into the mold structure 10 is solidified, the mold is released, and then the weir 17 is broken to separate the camshaft portion 1 from the runners 15 and 19. Even if this breakage is performed, the camshaft portions 1 do not fall apart one by one, and the two camshaft portions 1 can be obtained in a state where they are connected by the crossover portion 6 in the lift portion 5. Therefore, it is possible to hang the two camshaft portions 1 by hanging the crossover portion 6 on the hanger of the shot blasting device, and the sand dropping operation is facilitated.

  After shot blasting, the raised portion 5 is broken and removed from the camshaft portion 1 and further necessary deburring is performed to obtain a finished product (camshaft).

<Other embodiments>
As described above, according to the present invention, since the plurality of molds 11 are united with the mating surfaces 13 of the molds 11 in the vertical direction, it is easy to provide the hot water without increasing the thickness of the mold 11. An example of providing such a hot water is shown in FIG. This is an example in which the hot water is provided in the central portion of the cavity extending in the lateral direction, and the hot water forming portion 37 is provided in the central portion of each cavity forming portion 21 of the split mold 12. In the case of a mold structure in which a plurality of molds are poured in a stacked posture as described in the section “Problems to be Solved by the Invention”, if a hot water is provided in each cavity, Although the mold becomes thicker by the height, according to the present invention, the hot water can be provided by using the empty space above each cavity in the vertical mold 11, so that an increase in the mold thickness is avoided. Can do.

  Although the said embodiment is an example which obtains a cam shaft, this invention is applicable also to casting of other long castings, such as a balance shaft of an engine, for example.

  Moreover, although the said embodiment is an example which comprises the casting_mold | template structure 10 by the four casting_mold | templates 11, the number of the casting_mold | templates united can be made into 2 or more appropriate numbers.

DESCRIPTION OF SYMBOLS 1 Camshaft part 2 Sprue part 3 Vertical runner part 4 Horizontal runner part 5 Lift part 6 Transition part 10 Mold structure 11 Mold 12 Split mold 13 Matching surface 14 Cavity 15 Vertical runner 16 Lift 17 Weir 18 Spout cup 19 Yokoyu 26 26 Through-hole for forming a horizontal runway 27 Through-hole for forming a transitional runway

Claims (8)

A mold structure for casting a long cast product,
A plurality of molds each formed by combining a pair of (shell-shaped) split molds,
Each of the molds has a vertical mating surface of the split mold, and a plurality of cavities extending in parallel in the lateral direction with a vertical interval for taking a plurality of the cast products, and the plurality of cavities. One longitudinal runway extending in the vertical direction at one end side in the cavity longitudinal direction for guiding the molten metal,
The plurality of molds are combined with the split molds back to back so that the mating surfaces are parallel to each other,
A horizontal runway that connects the lower ends of the vertical runners of the plurality of molds is formed,
A gate is provided at the upper end of any one of the plurality of molds,
A mold structure characterized in that the vertical runway of each of the plurality of molds has a smaller passage cross-sectional area as it goes downward. In claim 1,
A casting mold structure, wherein three or more casting molds are combined, and the gate is provided in the vertical runner of the casting mold arranged on the center side thereof. In claim 1 or claim 2,
The mold structure characterized in that the weir connecting the vertical runner and the cavity is an upward runway from the vertical runway toward the cavity. In any one of Claim 1 thru | or 3,
The axis extending in the lateral direction of the cavity has an inclination angle of 1 degree to 3 degrees with respect to the horizontal line so that the position gradually increases from one end to the other end on the vertical runner side. Characteristic mold structure. In any one of Claims 1 thru | or 4,
Each of the pair of split molds constituting the mold has a through hole for forming the side runner,
A mold structure, wherein the split-type through-holes that are back-to-back are joined together, and a plug is fitted into the split-type through-holes located at both ends to form the side runner. In any one of Claims 1 thru | or 5,
Each of the plurality of molds is formed in a state where the upper end of the vertical runner is open,
A mold characterized in that a gate is provided at an upper end opening of a vertical runner of one of the plurality of molds, and an opening at the upper end of the vertical runner of another mold is closed with a stopper. Construction. In any one of Claims 1 thru | or 6,
Each of the plurality of molds includes a lift on the other end side in the cavity longitudinal direction,
A mold structure characterized in that at least one pair of split molds that are back-to-back are formed with through-holes that fit together so as to communicate the lifts of adjacent molds when they are back-to-back. A method for producing a mold structure for casting a long cast product,
By combining a pair of shell-shaped split molds, a plurality of cavities parallel to each other for taking a plurality of the cast products, and one end side in the longitudinal direction of the cavity for guiding the molten metal to the plurality of cavities Forming a mold having a first runner extending in the direction of alignment and having a passage cross-sectional area that decreases from one end to the other;
A step of stacking and combining a plurality of the molds such that the mating surfaces of the split molds lie down;
The combined mold obtained by the above stacking has a plurality of cavities of the respective molds extending in the horizontal direction at intervals, and the cross-sectional area of the passage becomes smaller as the first runner extends in the vertical direction and goes downward. A process of rotating to become a vertical runway;
Providing a gate at the upper end of the vertical runner of any of the above-mentioned combined molds,
In the split mold, a through hole is formed for communicating the other ends of the first runner of the mold that are adjacent to each other by the stacking.
In the step of stacking the molds, the split-type through holes that are back-to-back are aligned with each other, and the lower split-type through hole in the lowermost mold and the upper split mold through-hole in the uppermost mold are plugged. By closing, a second runner that connects the first runners of the plurality of molds is formed,
In the step of rotating the mold group, the combined mold is rotated so that the second runner is a horizontal runner that communicates the lower ends of the vertical runners of each of the plurality of molds. Manufacturing method.

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