JPH0634855U - Mold structure - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object to provide a mold structure capable of extending the life. [Structure] A mold structure for casting a casting product having a corner. Partial shape of the mold corresponding to the corner portion is formed in a concave shape having a predetermined curvature.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mold structure, and is particularly suitable for casting a casting product having a corner.

[0002]

[Prior art]

 When the cylinder block 1 shown in FIG. 4 is cast by DC casting, the mold is composed of a metal main mold that is divided into a plurality of parts such as top, bottom, left and right, and a metal mold that is placed in the hollow part of the main mold. It is composed of children. The main mold is formed to have an inner wall having the same shape as the outer shape of the cylinder block 1, and the insert is formed to have an outer wall having the same shape as the inner shape of the cylinder block 1. Then, by arranging the insert in the hollow portion of the main mold, a hollow portion having the same shape as the cylinder block 1 is defined.

Then, a molten metal is poured into the cavity from the lower side, and the molten metal in the entire cavity is cooled and solidified, whereby a cast product (cylinder block 1) is cast.

[0004]

[Problems to be solved by the device]

 However, the above-mentioned prior art has the following problems. That is, when the cylinder block 1 is continuously manufactured, there is a probability that defects (product shavings, mold drop, etc.) may occur at the edge portion (corner portion) 3 of the bottom surface 2 of the cylinder block 1 shown in FIGS. 6 and 7. It's getting higher.

As a result of investigating the cause of the defect, it was found that there is a problem in long-term use of the mold. To explain this cause, as shown in FIG. 5, the conventional mold forms the edge portion 3 of the cylinder block 1 (the acute-angled shape required as the product shape), so that the main mold 4 and the insert 5 are butted. , An acute-angled concave portion 6 is defined.

Then, the metal melt flows into the cavity of the mold, but the metal melt easily stays in the acute-angled concave portion 6. Therefore, the recess 6 is in a heat mass (heat accumulation) state, and thermal stress is concentratedly generated on the mold surface defining the recess 6.

When this mold is frequently used, concentrated thermal stress is repeatedly generated in the concave portion 6, and the mold surface is likely to be extremely deteriorated. As shown in FIG. A crack K will occur. Furthermore, there is a possibility that cracks K may progress to cracks.

The present invention has been made in view of such problems, and an object thereof is to provide a mold structure capable of extending the life.

[0009]

[Means for Solving the Problems]

 The gist of the mold structure of the present invention is that, in a mold structure for casting a casting product having a corner, a part of the mold corresponding to the corner is formed in a concave shape having a predetermined curvature. And the structure.

[0010]

[Action]

 According to the mold structure of the present invention, the metal melt does not easily stay in the concave mold-shaped portion having a predetermined curvature, and a heat mass state does not occur. As a result, there are no places where thermal stress is repeatedly generated in a concentrated manner, and the mold according to this example has excellent durability even after long-term use.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are intended to limit the scope of the present invention to them unless otherwise specified. It's just an example. In addition, the same components as those shown in FIGS. 5 to 7 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, the mold structure of this embodiment has a curved surface shape in which a concave portion 9 corresponding to the edge portion 3 of the cylinder block 1 is formed with a predetermined radius of curvature R. The concave portion 9 has curved curved concave portions formed at the edges of the main die 7 and the insert 8, and is defined by abutting the main die 7 and the insert 8. It

Next, the influence of the molten metal on the mold in which the recess 9 of the present embodiment is formed will be described. Since the concave portion 9 of the present embodiment has a curved surface shape, the molten metal flows into the entire void portion uniformly without using the concave portion 9 as a retention site. Moreover, since the contact area between the recess 9 and the molten metal is larger than that of the recess 6 having the conventional structure, the amount of heat of the molten metal that has flowed into the recess 9 is immediately lost and the cooling is likely to occur. Does not enter into a heat mass state.

As a result, the mold structure of the present embodiment has no places where concentrated thermal stress is likely to occur, and is excellent in durability even when used for a long period of time. The optimum value of the radius of curvature R of the recess 9 where the molten metal does not stay is about 3 mm.

Here, by forming the recessed portion 9 of the present embodiment in the mold, the cast cylinder block 1 is provided with the bead 10 as shown in FIGS. 2 and 3. The ball spot 9 can be easily ground to an acute-angled edge portion (corner portion 3) by machining.

In the present embodiment, the edge portion 3 of the bottom surface 2 of the cylinder block 1 has been described as an example, but this is not intended to limit the scope of the present invention, and an acute shape of another cast product may be used. It can be sufficiently applied to the mold structure to be formed.

[0017]

[Effect of device]

 As described above, according to the mold structure of the present invention, by forming a part of the mold corresponding to the corner of the casting product into a concave shape having a predetermined curvature, the molten metal has a concave shape. A part of the metal mold is not used as a retention area, and since the contact area with the molten metal is large, the cooling rate of the molten metal is accelerated, and there are no areas where a heat-mass state occurs locally.

Therefore, the present invention can provide a mold structure in which thermal stress is not intensively generated and which has excellent durability, and which has a long life.

[Brief description of drawings]

FIG. 1 is a sectional view showing a corner of a casting of the present invention and a part of a mold shape corresponding to the corner.

FIG. 2 is a view showing a bottom surface of a cylinder block cast by the mold structure of the present invention.

FIG. 3 is a sectional view taken along the line III-III shown in FIG.

FIG. 4 is a perspective view showing a cylinder block cast by a low pressure casting method.

FIG. 5 is a cross-sectional view showing a corner of a conventional casting and a part of a mold shape corresponding to the corner.

FIG. 6 is a view showing a bottom surface of a cylinder block cast by a conventional mold structure.

7 is a sectional view taken along the line VII-VII in FIG.

[Explanation of symbols]

 1 Cylinder Block 2 Bottom of Cylinder Block 3 Edge Part (Corner) 4 Conventional Main Mold (Mold) 5 Conventional Insert (Mold) 6 Conventional Mold Recess 7 Mold of the Present Invention (Mold) 8 Nest (mold) of the present invention 9 Recessed portion 10 Begging K Crack R Curvature radius

Claims (1)

[Scope of utility model registration request] 1. A mold structure for casting a casting product having a corner, wherein a part of the mold corresponding to the corner is formed in a concave shape having a predetermined curvature. Construction.