JP6921730B2 - Manufacturing method of cooling structure - Google Patents

Description

The present invention relates to a method for manufacturing a cooling structure, and more particularly to a method for manufacturing a cooling structure capable of securing a cross-sectional area of a cooling path.

Some cooling structures such as molds, in which a cooling path for flowing a refrigerant such as cooling water is formed inside, are provided with a cooling path along a predetermined end face of the cooling structure. As a method for manufacturing such a cooling structure, for example, a groove is formed along the end surface of the main body of the cooling structure, a lid is arranged in the groove so as to be separated from the bottom of the groove, and the side of the lid and the groove is arranged. A method is known in which a groove is used as a cooling path by overlay welding so as to close the opening of the groove while welding the wall surface (Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-52892

However, in the above-mentioned conventional technique, although it depends on the shape and dimensions of the lid, the lid is melted by the heat during overlay welding, and the melted lid falls into the groove or is in a molten state through the melted portion of the lid. Welded metal may fall into the groove. As a result, the cross-sectional area of the cooling path due to the groove may be narrowed or the cooling path may be blocked.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a cooling structure capable of securing a cross-sectional area of a cooling path.

In order to achieve this object, the method for manufacturing a cooling structure of the present invention has a first cooling passage and a second cooling passage that communicate with each other, and a welding metal is built-up welded to a metal main body. A method of manufacturing a body, in which a groove opening in an end surface of the main body is filled with a support material from the bottom of the groove to a predetermined height, and a lid is placed on the support material filled by the groove filling process. The mounting step of mounting, the welding step of performing overlay welding to weld the weld metal to the lid and the main body portion mounted by the previously described mounting step to close the opening of the groove, and communication with the groove. After the first cooling path forming step of forming the first cooling path and the welding step, the support material in the groove is discharged to the outside from the first cooling path formed by the first cooling path forming step. A second cooling path forming step is provided in which the portion from which the support material is discharged is used as the second cooling path.

According to the method for manufacturing a cooling structure according to claim 1, a support material is filled in a groove opened in an end surface of a main body portion, and a lid is placed on the support material, and the groove opening is made of a weld metal by a welding process. Close. Therefore, the support material can catch the lid melted by the heat during overlay welding and the weld metal that tends to penetrate into the groove bottom side of the lid. Then, the support material is discharged from the first cooling passage to the outside, and the portion where the support material is discharged is used as the second cooling passage, so that the cross-sectional area of the second cooling passage can be secured.

According to the method for manufacturing a cooling structure according to claim 2, the width of the lid is set to be substantially the same as the groove width of the groove of the portion where the support material is packed. When the width of the lid is larger than the groove width of the groove of the portion where the support material is packed, a part of the surface of the lid on the groove bottom side comes into contact with the main body. The contacting portion tends to be an unwelded portion between the lid and the main body portion. When the refrigerant is passed through the second cooling path, stress is generated in the cooling structure due to a difference in the amount of thermal expansion between the outside and the second cooling path side. Due to this stress, cracks are likely to proceed from the unwelded portion between the lid and the main body. On the other hand, by setting the width of the lid to be substantially the same as the groove width of the groove of the portion where the support material is packed, the surface of the lid on the groove bottom side can be prevented from coming into contact with the main body. Therefore, it is possible to prevent an unwelded portion from the main body portion from being formed on the groove bottom side of the lid. Since the formation of the unwelded portion can be suppressed in this way, even if stress is generated in the cooling structure, the progress of cracks from the unwelded portion between the main body and the lid can be suppressed.

Further, since the width of the lid is set to be substantially the same as the groove width of the groove where the support material is packed, the weld metal directly contacts the support material through the gap between the side wall surface of the groove and the lid. Can be suppressed. As a result, it is possible to prevent the molten support material from being solidified again due to the direct contact of the weld metal and reducing the cross-sectional area of the second cooling path. As a result, in addition to the effect of claim 1, the durability of the cooling structure can be improved, and the cross-sectional area of the second cooling path can be easily secured.

According to the method for manufacturing a cooling structure according to claim 3, a member capable of shifting from a first state having no fluidity to a second state having fluidity is used as a support material. In the grooving process, the support material in the first state is packed in the groove, so that the support material can be easily packed evenly in the groove, and even if the main body is tilted or moved, the packed support material is biased in the groove. Can be prevented. That is, the support material can be easily handled during the grooving process and after the grooving process.

Since the support material is transferred from the first state to the second state in the transition step after the welding step, the support material can be easily discharged from the first cooling path to the outside in the second cooling path forming step. As a result, in addition to the effects of claim 1 or 2, the support material can be easily handled during the grooving process and after the grooving process while ensuring the discharge performance of the support material.

According to the method for manufacturing a cooling structure according to claim 4, the support material is formed in the first state by solidifying the particles with a pyrolytic binder. In the transition step, the steel body and the weld metal are modified while heating to a temperature higher than the decomposition temperature of the pyrolyzable binder to decompose the pyrolyzable binder and transfer the support material to the second state. .. Since the support material is moved to the second state when the main body and the weld metal are modified, in addition to the effect of claim 3, the number of steps can be suppressed.

It is a perspective view of the cooling structure in 1st Embodiment of this invention. (A) is a side view of a schematic cooling structure, and (b) is a top view of the cooling structure seen from the direction of arrow IIb in FIG. 2 (a). (A) is a top view of the main body of the cooling structure, and (b) is a cross-sectional view of the main body in line IIIb-IIIb of FIG. 3 (a). (A) is an explanatory diagram for explaining the grooving process and the mounting process, and (b) is an explanatory diagram for explaining the welding process. (A) is an explanatory diagram for explaining a molding process, and (b) is an explanatory diagram for explaining a first cooling path forming process. (A) is an explanatory view explaining the process of forming the 2nd cooling passage, and (b) is the cross-sectional view of the cooling structure in which the 2nd cooling passage was formed. (A) is an explanatory view explaining the grooving step and the mounting step of the manufacturing method of the cooling structure in the second embodiment, and (b) is the top view of the main body part after the mounting step. (A) is an explanatory view explaining a welding process, and (b) is a cross-sectional view of a cooling structure in which a second cooling path is formed.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, the cooling structure 1 in the first embodiment will be described with reference to FIG. FIG. 1 is a perspective view of the cooling structure 1. In FIG. 1, the first cooling passage 4 and the second cooling passage 5 formed in the base 2 and the cylinder portion 3 are shown by broken lines. Further, in FIG. 1, only the upper end of the two first cooling passages 4 on the back side is shown.

As shown in FIG. 1, the cooling structure 1 is a steel mold for forming a water jacket of a cylinder block. The cooling structure 1 includes a thick plate-shaped base 2 and three substantially cylindrical cylinder portions 3 erected on the upper surface 2a of the base 2. In the cooling structure 1, a plurality of first cooling passages 4 are formed in the base 2 and the cylinder portion 3 along the axial direction of the cylinder portion 3, and the cylinder portion 3 is formed along the axial tip surface 3a of the cylinder portion 3. A plurality of second cooling passages 5 are formed therein.

The three cylinder portions 3 are arranged on the base 2 in a state in which the three cylinder portions 3 are oriented in the axial direction in the plate thickness direction of the base 2 and are arranged in a row. The outer peripheral surface and the inner peripheral surface of the adjacent cylinder portions 3 are continuous, and the hollow portion of each cylinder portion 3 is continuous. The number of cylinder portions 3 can be changed as appropriate.

The plurality of first cooling passages 4 and second cooling passages 5 are flow paths through which a refrigerant (for example, cooling water) for cooling the cooling structure 1 flows when the water jacket is manufactured by using the cooling structure 1. .. The plurality of first cooling passages 4 are arranged in the portions to which the cylinder portions 3 are connected. The first cooling passage 4 opens in the lower surface 2b of the base 2 and is formed from the lower surface 2b to the front of the tip surface 3a of the cylinder portion 3.

The plurality of second cooling passages 5 are flow paths connecting the first cooling passages 4 to each other. The second cooling passage 5 is formed along the tip surface 3a on substantially half or substantially the entire circumference of the cylinder portion 3. The cooling structure 1 is cooled by supplying the refrigerant to one of the two first cooling passages 4 connected to both sides of the second cooling passage 5 and discharging the refrigerant from the other.

Next, a method of manufacturing the cooling structure 1 will be described with reference to FIGS. 2 (a) to 6 (b). In addition, in FIG. 2A to FIG. 6B, in order to facilitate the explanation, a model of a schematic cooling structure 1 in the case where one cylinder portion 3 is used will be described. First, the schematic cooling structure 1 used in the description of the manufacturing method will be described with reference to FIGS. 2 (a) and 2 (b). FIG. 2A is a side view of a schematic cooling structure 1. FIG. 2B is a top view of the cooling structure 1 as viewed from the direction of arrow IIb in FIG. 2A.

As shown in FIGS. 2A and 2B, in the cooling structure 1, one cylinder portion 3 is erected on the upper surface 2a of the base 2, and four first cooling passages 4 and two are provided. The second cooling passage 5 of the above is provided. The four first cooling passages 4 are arranged along the axial direction of the cylinder portion 3 at positions separated by about 90 ° in the circumferential direction of the cylinder portion 3, respectively. The two second cooling passages 5 are arranged axially symmetrically along the tip surface 3a of the cylinder portion 3 on substantially half the circumference of the cylinder portion 3, respectively.

The two second cooling passages 5 do not communicate with each other, and the upper ends of the two first cooling passages 4 are connected to the one second cooling passage 5. Two first cooling passages 4 are connected to both ends of the second cooling passage 5. As a result, the flow of the refrigerant in the first cooling passage 4 and the second cooling passage 5 can be made difficult to stagnate.

The cooling structure 1 is formed by overlay welding a welded metal 7 to a main body 6. The main body 6 is composed of a base 2 and a part of the cylinder 3 on the base 2 side (hereinafter referred to as “main body cylinder 6a”). The weld metal 7 is a part of the cylinder portion 3 constituting the main body cylinder 6a from the end surface 6b in the axial direction farthest from the base 2 to the tip end surface 3a of the cylinder portion 3. The second cooling passage 5 is formed on the end surface 6b side of the main body cylinder 6a.

Next, a method of manufacturing the cooling structure 1 will be described in order with reference to FIGS. 3 (a) to 6 (b). First, as shown in FIGS. 3 (a) and 3 (b), a main body portion 6 in which the main body cylinder 6a is erected on the upper surface 2a of the base 2 is prepared. Next, on the end surface 6b of the main body portion 6, two arcuate grooves 8 are formed axially symmetrically on the substantially half circumference of the main body cylinder 6a. The groove 8 is a portion that serves as a second cooling passage 5. The groove 8 opens in the end face 6b. The side wall surface 8b connects the opening and the groove bottom 8a of the groove 8.

The groove 8 is formed on the end surface 6b of the main body 6 by cutting using a tool such as an end mill. The method of forming the groove 8 is not limited to cutting, and the groove 8 may be formed by grinding, laser processing, or the like. Further, the main body portion 6 in which the groove 8 is formed in the end surface 6b in advance may be prepared.

The depth H1 of the groove 8 from the groove bottom 8a to the opening is constant over the circumferential direction. The groove width W1 of the groove 8, which is the distance between the pair of side wall surfaces 8b, is constant over the circumferential direction and the vertical direction (the depth direction of the groove 8). As a result, the groove 8 can be easily formed continuously in the circumferential direction.

After forming the groove 8 in the main body portion 6, as shown in FIG. 4A, a grooving step of filling the groove 8 of the main body portion 6 with the support material 9 is performed. After that, a mounting step of placing the lid 10 on the support material 9 packed by the grooving step is performed. With the lid 10 mounted on the support material 9, the support material 9 may be packed in the groove 8 and the grooving step and the mounting step may be performed at the same time.

The support material 9 is a member capable of shifting from a first state having no fluidity to a second state having fluidity. In the present embodiment, the support material 9 is formed in the first state by solidifying particles such as sand with a thermally decomposable binder.

A pyrolytic binder is a binder that decomposes by heating at a high temperature. The decomposition of the pyrolyzable binder is not only the decomposition by the oxidation reaction of the pyrolyzable binder, but also the one in which the pyrolyzable binder itself is vaporized by heating at a high temperature, and the binder (coagulant) by the dehydration reaction. ), Including those that lose their role. Examples of the pyrolytic binder include organic binders such as furan resin and phenol resin, and inorganic binders such as cement and water glass. The particles do not melt at the temperature at which the pyrolytic binder is decomposed, and powders of inorganic compounds such as alumina and zirconia are exemplified in addition to sand composed of various minerals.

The support material 9 in the first state is formed in an arc shape that is the same as the shape of the groove 8 when viewed from above. The width W2 of the support material 9 in the first state (dimensions in the left-right direction of the paper surface in FIG. 4A) is set to be substantially the same as the groove width W1 of the groove 8. The height H2 of the support material 9 in the first state (dimensions in the vertical direction of the paper surface in FIG. 4A) is set smaller than the depth H1 of the groove 8. Further, the length (circumferential dimension) of the support material 9 in the first state is substantially the same as the length (circumferential dimension) of the groove 8.

The lid 10 is a steel plate material, and is formed in an arc shape that is the same as the shape of the groove 8 when viewed from above. The width W3, which is the dimension between the widthwise end faces 10a (the end faces in the left-right direction of the paper surface in FIG. 4A), is set to be substantially the same as the width W2 of the support material 9 and the groove width W1 of the groove 8. The sum of the thickness H3 of the lid 10 (dimensions in the vertical direction of the paper surface in FIG. 4A) and the height H2 of the support material 9 is substantially the same as the depth H1 of the groove 8. Further, the length of the lid 10 (circumferential dimension) is substantially the same as the length of the groove 8 (circumferential dimension).

In the present specification, when the dimensions of the two members are substantially the same, the dimensions of the two members are completely the same, or the dimensions of the member to be fitted are slightly smaller than those of the member to be fitted, and the dimensional difference thereof. Is 1 mm or less (preferably 0.5 mm or less, more preferably 0.1 mm or less). In addition, when fitting to a member on the fitting side with the member on the fitting side cooled to a smaller size, the dimension of the member on the fitting side is larger than the dimension of the member on the fitting side at room temperature (room temperature). May be slightly larger. Regarding the relationship between the dimensions of the two members at room temperature, the dimensions of the two members may be substantially the same.

In the grooving step, when the support material 9 in the first state is fitted into the groove 8, the support material 9 is packed in the groove 8 from the groove bottom 8a to a predetermined height as shown in FIG. 4 (b). Then, in the mounting step, when the lid 10 is placed on the support material 9, the lid 10 is also fitted into the groove 8, and the groove 8 is filled with the support material 9 and the lid 10 with almost no gap. Then, the upper surface of the lid 10 (the surface opposite to the groove bottom 8a) and the end surface 6b of the main body 6 are flush with each other. Further, by fitting the lid 10 into the groove 8, the positioning of the lid 10 with respect to the groove 8 can be easily performed.

After the mounting step, as shown in FIG. 4B, overlay welding is performed to weld the weld metal 7 to the end surface 6b of the lid 10 and the main body 6, and the welding step of closing the opening of the groove 8 is performed. .. In the welding process, the filler metal is melted into the weld metal 7 by the arc discharge between the lid 10 and the end face 6b and the nozzle 11. Then, while the welded metal 7 in the molten state adheres to the lid 10 and the end face 6b, the lid 10 and the main body 6 are melted, and the melted portion is solidified to weld the weld metal 7, and the lid 10 and the main body are welded. The portion 6 is welded. In the welding process, a part of the main body 6 and the lid 10 is melted, and the main body 6, the weld metal 7 and the lid 10 are integrated. For convenience, the boundaries between the main body 6, the weld metal 7, and the lid 10 are shown.

For overlay welding, any method such as a shielded metal arc welding method, a CO ₂ welding method, a MAG welding method, or a MIG welding method may be used. Further, the weld metal 7 (welding material) is preferably made of the same material as the main body 6. As a result, when the main body 6 and the weld metal 7 are heat-treated, or when the cooling structure 1 is used as a mold, the coefficient of thermal expansion of the main body 6 and the weld metal 7 can be made the same, and the main body can be made the same. It is possible to prevent stress from being generated in the welded portion between 6 and the weld metal 7.

In the welding process, a plurality of layers of the weld metal 7 by overlay welding are stacked. It is preferable that the lid 10 and the end face 6b are continuously overlaid welded in the circumferential direction. In this case, since the nozzle 11 is moved in the circumferential direction, overlay welding can be facilitated. However, since the heat during welding is continuously applied to the lid 10, the lid 10 is likely to be melted by the heat during welding.

Therefore, after the overlay welding of the lid 10 and the end face 6b is continuously performed in the radial direction, the overlay welding may be repeated by slightly moving in the circumferential direction and continuously performing the overlay welding in the radial direction again. In this case, although it depends on the width of the bead of welding and the radial dimension of the end face 6b, the heat at the time of welding can be intermittently applied to the lid 10, so that the heat at the time of welding makes it difficult for the lid 10 to melt. ..

In the welding step, as shown by the alternate long and short dash line in FIG. 5A, the weld metal 7 is welded to the main body 6 so that the size of the weld metal 7 is larger than that of the finished product. After that, the excess portion of the weld metal 7 is removed by cutting or grinding, and the weld metal 7 is formed into the shape shown by the solid line in FIG. 5 (a) (molding step).

Next, as shown in FIG. 5B, a first cooling path forming step of forming the first cooling path 4 from the lower surface 2b of the base 2 toward the groove 8 is performed using a cutting tool 12 such as a drill. Even if the first cooling passage 4 is communicated with the groove 8, the support material 9 is hardly discharged from the first cooling passage 4 because the support material 9 is in the first state having no fluidity.

After the first cooling path forming step, the main body 6 and the weld metal 7 are subjected to heat treatment such as quenching and tempering, and the steel main body 6 and the weld metal 7 are subjected to a heat treatment step of modifying the steel main body 6 and the weld metal 7 to high hardness. In this heat treatment step, the main body 6 and the weld metal 7 are heated at a temperature higher than the decomposition temperature of the thermally decomposable binder in the support material 9. Therefore, in the heat treatment step, the thermally decomposable binder of the support material 9 in the first state is decomposed, and the support material 9 shifts from the first state to the second state. Since the heat treatment step of modifying the main body 6 and the weld metal 7 also serves as a transition step of shifting the support material 9 from the first state to the second state, the number of steps is increased as compared with the case where the heat treatment step and the transition step are provided respectively. Can be suppressed.

Further, by performing the first cooling path forming step before the transition step (heat treatment step), the gas generated by the decomposition of the thermally decomposable binder in the transition step can be released from the first cooling passage 4. In particular, by directing the first cooling passage 4 upward with respect to the groove 8, it is possible to easily release the gas from the first cooling passage 4, and the support material 9 that has shifted to the second state is the first cooling passage 4. It is possible to prevent the support material 9 from falling into the heat treatment furnace or the like due to being discharged from the heat treatment furnace. Further, in the first cooling path forming step, since the main body portion 6 before being heat-treated in the transition step to become high hardness is cut, the formation of the first cooling path 4 can be facilitated.

After the transition step (heat treatment step), as shown in FIG. 6A, the support material 9 in the second state having fluidity is discharged from the first cooling passage 4 to the outside (second cooling passage forming step). In the second cooling path forming step, by injecting a fluid such as gas or liquid from the first cooling body 4 and discharging the support material 9, it is possible to prevent the support material 9 from remaining in the groove 8, and the support material 9 can be made difficult to remain. Easy to discharge. Further, since two first cooling passages 4 are connected to both ends of the groove 8 (second cooling passage 5) (see FIGS. 2 (a) and 2 (b)), support is provided on both ends of the groove 8. Material 9 can be hard to remain.

As shown in FIG. 6B, the portion where the support material 9 is discharged becomes the second cooling passage 5 due to the discharge of the support material 9. The portion of the groove 8 surrounded by the groove bottom 8a, the side wall surface 8b, and the lid 10 is the second cooling passage 5. In this way, the cooling structure 1 is manufactured by forming the first cooling passage 4 and the second cooling passage 5 that communicate with each other in the main body portion 6 and the weld metal 7.

According to the manufacturing method of the cooling structure 1 as described above, the groove 8 is filled with the support material 9, and the welding step is performed so as to close the opening of the groove 8 with the lid 10 placed on the support material. Here, when there is a support material 9 and there is no lid 10, the heat during welding directly acts on the support material 9, or the molten metal 7 in a molten state comes into direct contact with the support material 9. do. The support material 9 may be melted by these heats, and the support material 9 may be welded to the groove bottom 8a and the side wall surface 8b of the groove 8. In this case, the welded support material 9 narrows the cross-sectional area of the second cooling passage 5.

When the lid 10 is provided and the support material 9 is not provided, the width W3 of the lid 10 is made larger than the groove width W1 of the groove 8 so that the lid 10 is arranged apart from the groove bottom 8a. Needs to be placed on the end face 6b of the main body 6. Further, the groove 8 is provided with a narrow portion in which the groove width W1 on the groove bottom 8a side is narrower than the width W3 of the lid 10 and a wide portion in which the groove width W1 on the opening side is wider than the width W3 of the lid 10. The lid 10 may be fitted in the portion, and the lid 10 may be arranged at a distance from the groove bottom 8a. In these cases, the lid 10 melted by the heat at the time of welding is welded to the groove bottom 8a and the side wall surface 8b, or the welded metal 7 in the molten state passes through the melted portion of the lid 10 and is more in the groove bottom than the lid 10. It invades the 8a side. As a result, the cross-sectional area of the second cooling passage 5 is narrowed by the molten and solidified lid 10 and the weld metal 7.

On the other hand, in the present embodiment, since the support material 9 and the lid 10 are provided, the lid 10 melted by the heat during welding and the weld metal 7 that tends to penetrate into the groove bottom 8a side of the lid 10 are supported materials. It can be taken at 9. As a result, it is possible to prevent the second cooling passage 5 from being narrowed in cross-sectional area due to the melted and solidified lid 10 and the weld metal 7.

Further, since heat is mainly transferred to the support material 9 through the lid 10, it is possible to make it difficult for the support material 9 to melt due to the heat during welding. As a result, it is possible to prevent the cross-sectional area of the second cooling passage 5 from being narrowed by the support material 9 that has been melted and solidified. As a result, the cross-sectional area of the second cooling passage 5 can be secured by using the support material 9 and the lid 10 together.

The lid 10 is not limited to a plate material having a rectangular cross section, and a bar material having a circular cross section may be used as the lid 10. However, when the thickness H3 of the lid 10 varies in the width direction such as a circular cross section, a small portion of the lid 10 having a small thickness H3 tends to melt in the thickness direction. On the other hand, in the present embodiment, since the lid 10 has a rectangular cross section, it is possible to prevent a part of the lid 10 from being easily melted in the thickness direction. As a result, it is possible to suppress the welding of the molten lid 10, the intrusion of the weld metal 7 into the groove bottom 8a side of the lid 10, and the melting of the support material 9, so that the cross-sectional area of the second cooling passage 5 can be secured.

Further, even when the lid 10 is provided and the support material 9 is not provided, the molten lid 10 can be welded to the groove bottom 8a and the side wall surface 8b by increasing the thickness H3 of the lid 10, or the groove bottom can be formed more than the lid 10. It is possible to prevent the weld metal 7 from invading the 8a side. However, in this case, even if the cross-sectional area of the second cooling passage 5 can be secured, since the thickness H3 of the lid 10 is large, the distance from the second cooling passage 5 to the tip surface 3a becomes long, and the second cooling passage 5 is used. The cooling efficiency on the tip surface 3a side is reduced.

Further, if the thickness H3 of the lid 10 is large, the groove bottom 8a (second cooling path 5) side of the lid 10 is difficult to melt during the welding process, and the lid 10 and the main body 6 are not welded on the groove bottom 8a side. The part is likely to remain. In the cooling structure 1 used as a mold, a difference in the amount of thermal expansion occurs between the outside where the molten metal and the like come into contact and the side where the refrigerant flows, and stress is generated. If there is an unwelded portion between the lid 10 and the main body portion 6, this stress makes it easier for cracks to progress from the unwelded portion. As a result, the durability of the cooling structure 1 is reduced.

On the other hand, in the present embodiment, by using the support material 9 and the lid 10 together, the thickness H3 of the lid 10 is compared with the case where the lid 10 is provided and the support material 9 is not provided under the same welding conditions. Even if the amount is halved, a sufficient cross-sectional area of the second cooling passage 5 can be secured. As a result, the degree of freedom of the usable lid 10 can be improved, and the cooling efficiency of the tip surface 3a side by the second cooling path 5 can be improved by bringing the second cooling passage 5 closer to the tip surface 3a.

Further, since the thickness H3 of the lid 10 can be reduced, the lid 10 can be easily melted up to the second cooling path 5 side during the welding process, and the unwelded portion between the lid 10 and the main body 6 can be hardly left. As a result, even if stress is generated in the cooling structure 1, the progress of cracks from the unwelded portion can be suppressed, so that the durability of the cooling structure 1 can be improved.

Further, even when the support material 9 and the lid 10 are used together, the narrow portion and the wide portion described above are provided in the groove 8 to fit the lid 10 in the wide portion, or the width W3 of the lid 10 is made larger than the groove width W1. Then, the lid 10 may be placed on the end surface 6b of the main body 6. However, in this case, since the width W3 of the lid 10 is larger than the groove width W1 of the groove 8 of the portion where the support material 9 is packed, a part of the surface of the lid 10 on the groove bottom 8a side comes into contact with the main body 6. The contacting portion tends to be an unwelded portion between the lid 10 and the main body portion 6 during the welding process.

On the other hand, in the present embodiment, the groove width W1 of the groove 8 at the portion where the support material 9 is packed and the width W3 of the lid 10 are substantially the same, so that the surface of the lid 10 on the groove bottom 8a side is the main body. It can be prevented from touching 6. Therefore, it is possible to prevent an unwelded portion from the main body portion 6 from being formed on the groove bottom 8a side of the lid 10. Since the formation of the unwelded portion can be suppressed in this way, even if stress is generated in the cooling structure 1, the progress of cracks from the unwelded portion can be suppressed. As a result, the durability of the cooling structure 1 can be improved.

Further, since the groove width W1 of the groove 8 at the portion where the support material 9 is packed and the width W3 of the lid 10 are substantially the same, there is almost no gap between the side wall surface 8b of the groove 8 and the lid 10. As a result, it is possible to prevent the weld metal 7 in the molten state from coming into direct contact with the support material 9 through the gap. Therefore, it is possible to prevent the molten support material 9 from solidifying again due to the direct contact of the weld metal 7 in the molten state at a high temperature and reducing the cross-sectional area of the second cooling passage 5. Therefore, it is possible to easily secure the cross-sectional area of the second cooling passage 5.

In the grooving step, the support material 9 in the first state having no fluidity is packed in the groove 8, so that the support material 9 can be easily packed in the groove 8 evenly, and even if the main body 6 is tilted or moved. , It is possible to prevent the packed support material 9 from being biased in the groove 8. That is, the support material 9 can be easily handled during the grooving process and after the grooving process. By uniformly filling the groove 8 with the support material 9, the cross-sectional area of the second cooling passage 5 which is the portion from which the support material 9 has been removed can be made uniform over the length direction.

Then, in the transition step after the welding step, the support material 9 shifts from the first state to the second state, so that the support material 9 can be easily discharged from the first cooling passage 4 in the second cooling path forming step. Therefore, by using the support material 9 that can shift between the first state having no fluidity and the second state having fluidity, while ensuring the discharge performance of the support material 9, the grooving process and grooving The support material 9 after the process can be easily handled.

Next, the second embodiment will be described with reference to FIGS. 7 (a) to 8 (b). In the first embodiment, the case where the width W3 of the lid 10 is substantially the same as the groove width W1 of the groove 8 has been described. On the other hand, in the second embodiment, the case where the width W4 of the lid 21 is smaller than the groove width W1 of the groove 8 will be described. The same parts as those in the first embodiment are designated by the same reference numerals, and the following description will be omitted.

FIG. 7A is an explanatory diagram illustrating a grooving step and a mounting step of the manufacturing method of the cooling structure 20 in the second embodiment. FIG. 7B is a top view of the main body 6 after the mounting process. FIG. 8A is an explanatory diagram illustrating a welding process. FIG. 8B is a cross-sectional view of the cooling structure 20 in which the second cooling passage 5 is formed. In the welding process, a part of the main body 6 and the lid 21 is melted, and the main body 6, the weld metal 7 and the lid 21 are integrated. For convenience, the boundaries between the main body 6, the weld metal 7, and the lid 21 are shown.

As shown in FIGS. 7 (a) and 7 (b), the lid 21 in the second embodiment is a steel plate material, and is formed in an arc shape substantially the same as the shape of the groove 8 in the top view. .. The sum of the thickness H3 of the lid 21 and the height H2 of the support material 9 is the same as the depth H1 of the groove 8. The width W4, which is the dimension between the end faces 10a in the width direction, of the lid 21 is set to be smaller than the width W2 of the support material 9 and the groove width W1 of the groove 8. The length of the lid 21 (circumferential dimension) is set smaller than the length of the groove 8 (circumferential dimension).

After fitting the support material 9 into the groove 8 in the grooving process, the lid 21 is inserted into the groove 8 and the lid 21 is placed on the support material 9 in the mounting process. A gap 23 (groove) is formed between the end face 10a and the end face 10a. Further, a gap 24 (groove) is formed between the end portion of the lid 21 in the length direction and the end surface of the groove 8 in the length direction.

The lid 21 includes a protrusion 22 that protrudes in the width direction from the end face 10a in the width direction. A plurality of protrusions 22 are arranged on both side width direction end faces 10a in the circumferential direction. The protrusion amount of the protrusion 22 is set to 1/2 of the difference between the groove width W1 and the width W4. As a result, the tips of the protrusions 22 on both sides in the width direction come into contact with the side wall surface 8b, so that the lid 21 can be arranged at the center of the groove 8 in the width direction. As a result, gaps 23 between the side wall surface 8b and the side wall surface 8b can be formed substantially uniformly on both sides of the lid 21 in the width direction.

After the mounting step, as shown in FIG. 8A, a welding step is performed in which the weld metal 7 is welded to the end surface 6b of the lid 21 and the main body 6 by overlay welding to close the opening of the groove 8. In the welding process, the groove width is such that the weld metal 7 in the molten state can penetrate into the gap 23 (see FIG. 7B) between the widthwise end surface 10a and the side wall surface 8b in the depth direction of the groove 8. The difference between W1 and the width W4 (the width of the gap 23) is set. The width of the gap 23 is determined by the conditions of overlay welding, the viscosity of the weld metal 7 in the molten state, and the like.

When the weld metal 7 penetrates into the gap 23 between the widthwise end surface 10a and the side wall surface 8b, the widthwise end surface 10a and the side wall surface 8b are welded by the weld metal 7 over the depth direction of the groove 8. After the welding step, as in the first embodiment, the first cooling path forming step, the transition step (heat treatment step), and the second cooling path forming step are performed in this order, as shown in FIG. 8 (b). The cooling structure 20 is manufactured.

According to the manufacturing method of the cooling structure 20 as described above, the width W4 of the lid 21 is smaller than the groove width W1 of the groove 8, so that the surface of the lid 21 on the groove bottom 8a side does not come into contact with the main body 6. can. Therefore, as in the first embodiment, the unwelded portion with the main body portion 6 can be prevented from being formed on the groove bottom 8a side of the lid 21, so that even if stress is generated in the cooling structure 20, the unwelded portion can be used. The progress of cracks can be suppressed.

Further, since the width direction end surface 10a and the side wall surface 8b are welded by the weld metal 7 over the depth direction of the groove 8 by the gap 23 between the width direction end surface 10a and the side wall surface 8b, the width direction end surface 10a and the side The unwelded portion between the wall surface 8b and the wall surface 8b can be eliminated. Thereby, the formation of the unwelded portion between the lid 21 and the main body portion 6 can be further suppressed. As a result, even if stress is generated in the cooling structure 20, the progress of cracks from the unwelded portion can be further suppressed, so that the durability of the cooling structure 20 can be further improved.

However, when the width W4 of the lid 21 is smaller than the groove width W1 of the groove 8, one of the widthwise end surfaces 10a of the lid 21 comes into contact with the side wall surface 8b unless the lid 21 is positioned in the width direction with respect to the groove 8. This makes it difficult for the contacted portion to be welded. On the other hand, in the present embodiment, the protrusions 22 of the lid 21 can form gaps 23 between the side wall surfaces 8b on both sides of the lid 21 in the width direction substantially uniformly.

Not limited to positioning of the lid 21 in the width direction using the protrusion 22, the lid 21 and the main body 6 are partially welded before the welding process to position the lid 21 with respect to the groove 8 in the width direction. Is also good. In this way, the positioning of the lid 21 in the width direction makes it easier for the weld metal 7 to penetrate into the gaps 23 on both sides of the lid 21 in the width direction over the depth direction of the groove 8. Therefore, the formation of the unwelded portion between the lid 21 and the main body 6 can be further suppressed. As a result, even if stress is generated in the cooling structure 20, the progress of cracks from the unwelded portion can be further suppressed, so that the durability of the cooling structure 20 can be further improved.

Further, since the length of the lid 21 is set to be smaller than the length of the groove 8, a gap 24 is also formed between the end portion of the lid 21 in the length direction and the end surface of the groove 8 in the length direction. The weld metal 7 also penetrates into the gap 24 in the depth direction of the groove 8, so that the end portion of the lid 21 in the length direction and the end surface in the length direction of the groove 8 are in the depth direction of the groove 8. Can be welded over. As a result, the formation of the unwelded portion between the lid 21 and the main body portion 6 can be further suppressed, so that even if stress is generated in the cooling structure 20, the progress of cracks from the unwelded portion can be further suppressed, and the cooling structure 20 can be further suppressed. Durability can be further improved.

If the weld metal 7 invades the gaps 23 and 24 between the lid 21 and the main body 6, the weld metal 7 may come into direct contact with the support material 9 and the support material 9 may melt. In this case, the melted and solidified support material 9 is welded to the lid 21 and the main body 6. However, the portion where the support material 9 melts is limited to the corner between the lid 21 and the main body portion 6, and the surrounding support material 9 receives the melted support material 9, so that the corner between the lid 21 and the main body portion 6 is narrow. The support material 9 is welded only to the closure. As a result, even if the weld metal 7 that has entered through the gaps 23 and 24 between the lid 21 and the main body 6 comes into direct contact with the support material 9, the cross-sectional area of the second cooling passage 5 can be sufficiently secured.

Although the present invention has been described above based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is easy that various modifications and improvements can be made without departing from the spirit of the present invention. It can be inferred from. For example, the present invention is not limited to the case where the groove 8 is formed on the axial end surface 6b of the main body portion 6, and the outer peripheral surface of the main body portion 6 may be used as the end surface and the groove 8 may be formed on the end surface. Further, the cross-sectional shape of the groove 8 may be formed in a V shape, a U shape, or the like.

In the second embodiment, the case where the groove (gap 23, 24) is I-shaped has been described, but the present invention is not necessarily limited to this, and the shape of the groove can be changed as appropriate. For example, the groove may be formed into a V-shape, a le-shape, a U-shape, a J-shape, a double-sided J-shape, or the like.

In each of the above embodiments, the case where the cooling structures 1 and 20 are molds for forming the water jacket of the cylinder block has been described, but the present invention is not necessarily limited to this. If it is a cooling structure having a first cooling passage 4 and a second cooling passage 5 communicating with each other inside, it cools molds other than those for water jackets of cylinder blocks, plunger chips, engine components, hydraulic equipment, and the like. The present invention may be applied to the structure. The shapes of the first cooling passage 4 and the second cooling passage 5 are appropriately set according to the cooling structure to which the present invention is applied. For example, the first cooling passage 4 may be formed in the weld metal 7.

In each of the above embodiments, the case where the main body 6 and the weld metal 7 are the same steel material has been described, but the present invention is not necessarily limited to this. The main body 6 and the weld metal 7 may be made of different steel materials. Further, the main body 6 and the welded metal 7 may be made of a metal other than the steel material, for example, cemented carbide. In the present invention, since the weld metal 7 is built-up welded to the main body 6, the degree of freedom of the material that can be used for the main body 6 and the weld metal 7 is high.

In each of the above embodiments, the case where the particles are solidified with a thermally decomposable binder to form the support material 9 in the first state has been described, but the present invention is not necessarily limited to this. Instead of the pyrolytic binder, the particles may be solidified with water-soluble inorganic salts (for example, tripotassium phosphate, potassium sulfate, sodium sulfate) to form a support material in the first state. Further, the support material in the first state may be formed by solidifying inorganic salts such as water-soluble sodium chloride. In these cases, water is supplied to the first cooling passage 4 communicating with the groove 8 to dissolve the inorganic salts in the water, thereby performing a transition step of shifting the support material from the first state to the second state. .. Further, the support material may be composed of only particles such as sand. In this case, since the support material has fluidity at all times, the transition step can be eliminated.

In each of the above embodiments, the sum of the thickness H2 of the support material 9 and the thickness H3 of the lids 10 and 21 is the same as the depth H1 of the groove 8, and the end surface 6b of the main body 6 and the upper surface of the support material 9 are formed. Although the case where and is on the same plane has been described, the present invention is not necessarily limited to this. The sum of the thickness H2 of the support material 9 and the thickness H3 of the lids 10 and 21 may be made larger than the depth H1 of the groove 8 so that the lids 10 and 21 project upward from the groove 8. Further, the thickness H2 of the support material 9 and the depth H1 of the groove 8 may be made the same, and the lids 10 and 21 may be placed on the support material 9 and the end surface 6b. In this case, a protrusion for positioning is provided on the end surface 6b so that the lids 10 and 21 do not shift with respect to the groove 8, or the lids 10 and 21 and the main body 6 are partially separated before the welding process. Welding is preferred.

Further, the sum of the thickness H2 of the support material 9 and the thickness H3 of the lids 10 and 21 may be set to be smaller than the depth H1 of the groove 8. In this case, overlay welding is performed so as to fill the groove 8 above the lids 10 and 21, and the weld metal is formed so that the upper surface of the weld metal 7 by overlay welding is flush with the end surface 6b of the main body 6. 7 may be machined or ground. As a result, the number of portions for cutting or grinding the weld metal 7 can be reduced, so that the processing time of the weld metal 7 can be shortened.

In each of the above embodiments, the case where the first cooling path forming step is performed after the welding step has been described, but the present invention is not necessarily limited to this. If the support material 9 to be packed in the groove 8 in the grooving step is in the first state having no fluidity, the first cooling path forming step may be performed at any timing before the second cooling path forming step. For example, when the groove 8 is formed after the first cooling passage 4 is formed, the time when the first cooling passage 4 and the groove 8 communicate with each other is referred to as the first cooling passage forming step.

In each of the above embodiments, the case where the first cooling path forming step is performed before the transition step (heat treatment step) has been described, but the present invention is not necessarily limited to this. The first cooling path forming step may be performed after the transition step. As a result, it is possible to prevent the support material 9 in the second state during the transition process from falling from the first cooling passage 4 into the heat treatment furnace or the like.

Further, when the first cooling path forming step is performed after the transition step, when the support material 9 in which the particles are hardened by the pyrolysis binder is used, the gas generated by the decomposition of the pyrolysis binder during the transition step is first cooled. I can't escape from Road 4. Therefore, the opening of the groove 8 is not partially closed in the welding process, and the gas generated by the decomposition of the thermally decomposable binder is discharged to the outside from a part of the opening. Then, after the transition step, all the openings of the groove 8 are closed.

When the groove 8 is completely closed, the support material 9 is discharged, so that the lids 10 and 21 melted by the heat during welding and the weld metal 7 invade the second cooling passage 5. Therefore, both ends of the groove 8 (second cooling passage 5) are arranged outside the portion where the two first cooling passages 4 are connected, and the portion that later closes the opening of the groove 8 is the first cooling passage 4. Set outside the part where is connected. As a result, since there is almost no flow of the refrigerant in the second cooling passage 5 outside the portion to which the first cooling passage 4 is connected, the cross-sectional area of the second cooling passage 5 in the portion where the refrigerant mainly flows can be secured.

Further, when the first cooling path forming step is performed after the transition step (heat treatment step), it is necessary to cut the main body portion 6 having a high hardness. Therefore, even if the first cooling passage 4 is cut to the front of the groove 8 before the transition step, the first cooling passage 4 is connected to the groove 8 after the transition step, and the first cooling passage 4 is completely formed. good. As a result, the range in which the hardened main body 6 is cut can be reduced, so that the first cooling path 4 can be easily formed.

1,20 Cooling structure 4 1st cooling path 5 2nd cooling path 6 Main body 6b End face 7 Welded metal 8 Groove 8a Groove bottom 8b Side wall surface 9 Support material 10,21 Lid 10a Width direction end face W1 Groove width W3, W4 Width

Claims (4)

A method for manufacturing a cooling structure, which has a first cooling passage and a second cooling passage communicating with each other, and manufactures a cooling structure in which a weld metal is overlaid welded to a metal main body.
A grooving process in which a support material is filled from the bottom of the groove to a predetermined height in a groove opened on the end surface of the main body.
A mounting step of placing a lid on the support material packed by the grooving step, and a mounting step.
A welding step of performing overlay welding to weld the weld metal to the lid and the main body portion placed by the above-described setting step to close the opening of the groove.
A first cooling path forming step of forming the first cooling path so as to communicate with the groove, and
After the welding step, the support material in the groove is discharged to the outside from the first cooling path formed by the first cooling path forming step, and the portion where the support material is discharged is referred to as the second cooling path. A method for manufacturing a cooling structure, which comprises a second cooling path forming step. The method for manufacturing a cooling structure according to claim 1, wherein the width of the lid is set to be substantially the same as the groove width of the groove at the portion where the support material is packed. The support material is a member capable of shifting from a first state having no fluidity to a second state having fluidity.
In the grooving step, the support material in the first state is packed in the groove.
The method for manufacturing a cooling structure according to claim 1 or 2, wherein after the welding step, a transition step of shifting the support material from the first state to the second state is performed. The main body and the weld metal are made of steel.
The support material is formed in the first state by solidifying the particles with a pyrolytic binder.
The transition step is characterized in that the main body and the weld metal are modified while the support material is transferred to the second state by heating to a temperature higher than the decomposition temperature of the thermally decomposable binder. The method for manufacturing a cooling structure according to claim 3.

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