Mold unit

Abstract

The present disclosure provides a mold unit capable of prolonging the fatigue life of a cover for temperature measurement. A mold unit (1) according to the present disclosure is provided with: a mold (2) having a through-hole penetrating from an outer surface to an inner surface defining a space into which a molten material is injected; a cover (3) formed from the same material as the mold and fixed to the mold by means of a welded section (7) so as to close the end of the through-hole (21) on the inner surface side of the mold; a thermocouple wire (4) having a folded portion (41), the tip of which is fixed to the surface of the cover on the outer surface side of the mold in a state of passing through the through hole; a cylindrical member covering the thermocouple wire in a state of passing through the through hole; and a support member (6) that supports the cylindrical member, the cylindrical member being fixed between the cover and the support member, the through-hole and the cover being not in contact with each other in a region other than the welded portion, and a recess having a bottom surface in a concavely curved shape being formed in the cover.

Description

Technical Field

[0001] This disclosure relates to mold units. Background Technology

[0002] Patent document 1 discloses a mold unit having a cover made of the same material as the mold, and the temperature of the mold can be accurately measured by measuring the temperature of the cover. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-086213 Summary of the Invention The problem that the invention aims to solve

[0004] However, in the mold unit disclosed in Patent Document 1, the cover undergoes thermal expansion due to contact with the molten metal and thermal shrinkage due to the spraying of the release agent. In this case, there is a problem that the cover may crack prematurely due to the stress amplitude caused by this thermal expansion and contraction.

[0005] This disclosure was made in view of the above-mentioned problems, and provides a mold unit that can mitigate the stress amplitude of the cap used for temperature measurement and thus extend the life of the cap. Technical means for solving problems

[0006] The mold unit involved in one aspect of this disclosure has: A mold having a through hole extending from an outer surface to an inner surface, the inner surface defining a space into which molten material is injected; The cover, made of the same material as the mold, is fixed to the mold by welding in such a way that it blocks the end of the mold on the inner surface side of the through hole; Thermocouple wire has a folded-back portion, and when it passes through the through hole, the front end of the folded-back portion is fixed to the outer surface of the mold in the cover. A cylindrical component, while passing through the through hole, covers the thermocouple wire; and Support component, supporting the cylindrical component The cylindrical component is fixed between the cover and the support component. The through hole and the cover do not contact each other in the area outside the welded part. The cover has a concave bottom surface that is curved, so that the cover can easily undergo elastic deformation when it expands or contracts with heat. Invention Effects

[0007] According to this disclosure, a mold unit can be provided that can mitigate the stress amplitude of a cover used for temperature measurement, thereby extending the life of the cover. Attached Figure Description

[0008] Figure 1 This is a top view of the mold unit involved in the embodiments of this disclosure. Figure 2 This is a cross-sectional view of the mold unit involved in the embodiments of this disclosure. Figure 3 It is a graph comparing the stress amplitude of the cover of the mold unit according to the embodiments of this disclosure with the stress amplitude of the cover of the flat plate shape. Figure 4 (a) is the thermal stress analysis condition of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (b) is a top view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (c) is a cross-sectional view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (d) is a cross-sectional view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (e) is the thermal stress analytical model of the cover according to the embodiments of this disclosure. Figure 4 (f) is the analytical model of thermal stress of the cover for the comparative example. Figure 5 This is the thermal stress analysis result of the cover in the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 6 This is a comparison of the stress amplitude of the cover in the mold unit involved in the embodiments and comparative examples of this disclosure. Detailed Implementation

[0009] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments. In addition, for the sake of clarity, the following description and drawings have been appropriately simplified.

[0010] <Composition of Mold Unit> Figure 1 This is a top view of the mold unit involved in the embodiments of this disclosure. Figure 2 This is a cross-sectional view of the mold unit involved in the embodiments of this disclosure.

[0011] The mold unit 1 includes a mold 2, a cover 3, a thermocouple wire 4, a cylindrical component 5, and a support component 6. In addition, the mold 2 and the cover 3 are welded together by a welding part 7.

[0012] Mold 2 is a mold used for casting, forming a chamber that defines a space for the inflow of molten material. Furthermore, in Figure 2 In the middle, the surface is composed of mold 2, cover 3 and welding part 7. Figure 2 The upper and middle surfaces form the inner surface of mold 2, creating a cavity. On the other hand, the surface on the opposite side of this inner surface (…) Figure 2 The lower surface is the outer surface of mold 2. Furthermore, the shape and size of mold 2 are determined according to the shape and size of the target casting. The material of mold 2 is determined according to the temperature of the molten material, but may be, for example, metals or alloys such as steel, iron, or cast iron.

[0013] The molten material flowing into the cavity formed by the mold 2 is, for example, molten iron, molten steel, molten aluminum, or other molten metals, molten alloys, or molten resins such as polycarbonate, polyvinyl chloride, ABS resin, and acrylic resin.

[0014] In addition, the mold 2 has a through hole 21 that extends vertically from the outer surface to the inner surface of the mold 2. A cover 3, a thermocouple wire 4, and a cylindrical component 5 that supports the thermocouple wire 4 are disposed in the through hole 21.

[0015] Here, the through hole 21 preferably has the following characteristics: Figure 2 The shape of the enlarged section on the inner surface of mold 2 is shown. By increasing the inner diameter of the inner surface of mold 2 in the through hole 21 and placing the cover 3 in that position, the area occupied by the cover 3 on the inner surface of mold 2 can be increased, thus improving the temperature responsiveness of the thermocouple wire 4. Furthermore, by reducing the inner diameter of the outer surface of mold 2, the volume of mold 2 can be ensured, reducing temperature changes in mold 2 during casting. In addition, in Figure 2 In this case, the through hole 21 is set to a cylindrical shape, but it can also be a polygonal prism shape, depending on the shape of the cover 3 and the cylindrical component 5.

[0016] The cover 3 transfers heat from the molten material flowing into the chamber formed by the mold 2 to the thermocouple wire 4. The cover 3 is configured to block the inner surface side of the mold 2 in the through hole 21, is welded to the mold 2 via the welding portion 7, and is supported by the cylindrical member 5. Furthermore, the outer periphery of the inner surface side of the cover 3 is welded to the mold 2 (the inner peripheral surface of the inner surface side of the through hole 21) via the welding portion 7 (see reference). Figure 1 , Figure 2 Furthermore, the cover 3 is formed of the same material as the mold 2. Additionally, the size of the cover 3 is determined based on the size of the through hole 21, etc.

[0017] Here, a heat-insulating space V is provided between the cover 3 and the mold 2 (refer to...). Figure 2Specifically, the cover 3 and the mold 2 are welded together via the welding part 7 while the heat-insulating space V is sandwiched between them and facing each other. That is, the cover 3 and the mold 2 do not contact each other in the area outside the welding part 7. According to this configuration, heat transferred from the molten material to the cover 3 can be prevented from escaping to the mold 2, so the temperature can be accurately measured using the thermocouple wire 4.

[0018] Furthermore, the cover 3 has a recess 31 on the outer surface side of the mold 2 to mitigate the stress amplitude of the cover 3. The recess 31 extends from the outer surface side of the mold 2 toward the inner surface side and is a bottomed recess with a bottom on the inner surface side. The bottom of the recess 31 is concave and curved toward the inner surface side of the mold 2. As a result, the cover 3 is not flat like the cover in Patent Document 1, but rather has a shape that gradually thins from the outer periphery toward the center (see reference). Figure 2 By using a recess 31 of this shape, deformation (elastic deformation) of the cover 3 (thin sheet) caused by expansion and contraction during the casting cycle is allowed, and the life of the cover 3 (thin sheet) can be extended by mitigating stress amplitude. In addition, the recess 31 has a corner portion 311.

[0019] Here, the flat-shaped cap disclosed in Patent Document 1 will repeatedly generate internal stress due to thermal expansion caused by contact with the molten metal and thermal contraction caused by the spraying of the release agent. As a result, due to the amplitude of the generated internal stress (stress amplitude), premature cracking will occur in the cap. Here, the maximum and minimum stress values ​​generated in the cap are obtained by the following formula (1).

[0020] Stress amplitude [MPa] = (maximum stress value [MPa] - minimum stress value [MPa]) / 2... (Equation 1)

[0021] On the other hand, the cover 3 according to the embodiments of this disclosure has a recess 31 for mitigating the stress amplitude of the cover 3. More specifically, the recess 31 has a shape such that, when the cover 3 undergoes thermal expansion and contraction, it is more prone to elastic deformation in the vertical direction (the thickness direction of the cover) compared to a flat cover. By elastically deforming the cover 3 in the vertical direction, the maximum stress value generated inside the cover 3 is reduced, and the minimum stress value is increased. As a result, the stress amplitude of the cover 3 is mitigated.

[0022] Figure 3 This is a graph comparing the stress amplitude of the cover of the mold unit according to the embodiments of this disclosure with the stress amplitude of the flat-shaped cover. Compared with the flat-shaped cover, the cover 3 according to the embodiments of this disclosure has a reduced maximum stress value and an increased minimum stress value, thereby mitigating the stress amplitude.

[0023] In addition, Figure 2In this design, the recess 31 is provided on the outer surface of the mold 2, but its position and size are determined based on the purpose of mitigating the stress amplitude of the cover 3. However, considering the amount and direction of deformation of the cover 3 and its influence on the shape of the casting, the recess 31 is preferably formed on the outer surface of the mold 2 within the cover 3. By forming the recess 31 on the outer surface of the mold 2 within the cover 3, when expansion and contraction occur in the cover 3, the cover 3 undergoes elastic deformation in the vertical direction, resulting in mitigation of the stress amplitude of the cover 3.

[0024] Furthermore, by providing a recess 31 in the cover 3, the thickness of the portion where the recess 31 is provided is reduced. By reducing the thickness of the cover 3, the temperature responsiveness of the thermocouple wire 4 is improved. However, if the thickness of the cover 3 is reduced throughout, the strength of the cover 3 may decrease. In order to minimize the decrease in the strength of the cover 3, the shape of the cover 3 is preferably a shape that is thick at the periphery and thin only at the center, that is, a shape in which the recess 31 is provided in the center of the cover 3. In addition, in combination with the above-mentioned effect of mitigating the stress amplitude of the cover 3, the cover shape of the present disclosure, in which the recess 31 is provided in the center of the outer surface side of the mold 2, is more preferably a cover shape.

[0025] Furthermore, the recess 31 is preferably concave-bent on the inner surface of the mold 2. Because the bottom surface of the recess 31 has a concave-bent shape, stress concentration occurring in the recess 31 can be mitigated when the cover 3 undergoes elastic deformation.

[0026] Furthermore, the corner portion 311 of the recess 31 preferably has a rounded shape (Japanese: R-shape). By having a rounded shape for the corner portion 311, stress concentration occurring at the corner portion 311 can be mitigated when the cover 3 undergoes elastic deformation.

[0027] Furthermore, the depth of the recess 31 is preferably 10% to 25% of the thickness of the cover 3. When the depth of the recess 31 is shallower than 10% of the thickness of the cover 3, the amount of elastic deformation of the cover 3 in the vertical direction becomes smaller, and the stress amplitude mitigation effect becomes smaller. In addition, when the depth of the recess 31 is deeper than 25% of the thickness of the cover 3, the strength of the cover 3 decreases.

[0028] Thermocouple wire 4 measures the temperature of cover 3. Thermocouple wire 4 is connected to cover 3 via fold-back portion 41 and is disposed inside cylindrical component 5. The thermocouple wire 4 is made of metals such as platinum-rhodium alloy, nickel-chromium alloy, nickel alloy, iron, and copper.

[0029] Furthermore, when a recess 31 is formed on the outer surface of the mold 2 in the cover 3, the folded-back portion 41 of the thermocouple wire 4 can also be configured to contact the bottom surface of the recess 31.

[0030] The cylindrical component 5 supports the cover 3 and contains a thermocouple wire 4. The cylindrical component 5 is supported by a support component 6. Furthermore, in... Figure 2 In this design, the cylindrical component 5 is cylindrical, but it can also be polygonal, depending on the shape of the through hole 21. Furthermore, the size of the cylindrical component 5 is determined by the size of the cover 3, the amount of molten material flowing into the cavity of the mold 2, and the size of the through hole 21.

[0031] Support member 6 supports cylindrical member 5. Furthermore, in Figure 2 In this design, the support member 6 is cylindrical, but it can also be polygonal, depending on the environment in which the support member 6 is located. Furthermore, the size of the support member 6 is determined by the size of the cylindrical member 5, etc.

[0032] As explained above, the mold unit 1 according to the embodiments of this disclosure has a cover 3 for measuring the temperature of the mold 2 at the bottom of the mold 2, and the cover 3 is provided with a recess 31 for mitigating stress amplitude. Therefore, it is possible to provide a mold unit that can mitigate the stress amplitude of the cover 3 for temperature measurement compared to the stress amplitude of the cover described in Patent Document 1. The inventors confirmed this by performing stress analysis on the model. The stress analysis performed by the inventors will now be described. The following stress analysis was performed using specified software. [Example]

[0033] <Analytical Conditions of Thermal Stress in Mold Units> Next, the thermal stress analysis results of the mold unit involved in the embodiments of this disclosure are shown. Figure 4 (a) is the thermal stress analysis condition of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (b) is a top view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (c) is a cross-sectional view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (d) is a cross-sectional view of the mold and cover in the thermal stress analysis model of the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 4 (e) is the thermal stress analytical model of the cover according to the embodiments of this disclosure. Figure 4 (f) is the analytical model of thermal stress of the cover for the comparative example.

[0034] As a thermal stress analytical model, such as Figure 4 (b) and Figure 4 The mold and cover are configured as shown in (c), with a through hole provided below the cover, thereby simulating the shape of the mold unit according to the embodiments of this disclosure. Additionally, as shown... Figure 4As shown in (d), the upper periphery of the cover is set to a tie-fit, simulating the welded portion between the mold and the cover according to the embodiment of this disclosure. On the other hand, the portion of the side portion of the cover other than the upper periphery is set to a slight sliding position, simulating the point where the mold and the cover do not contact each other except at the welded portion according to the embodiment of this disclosure. In addition, as for the shape of the cover, Figure 4 The lid shape involved in the embodiment of this disclosure shown in (e) is set as in Example 1, and the lid shape is set as in Example 1. Figure 4 The conventional shape shown in (f) is designated as Comparative Example 1. Here, both the cover of Example 1 and the cover of Comparative Example 1 are circular plates with equal maximum thickness, but the cover of Example 1 has a recess in the center of the lower side of the circular plate. Furthermore, this recess has a concave curved shape on the bottom surface and rounded corners.

[0035] <Results of Thermal Stress Analysis> Figure 5 This is the thermal stress analysis result of the cover in the mold unit involved in the embodiments and comparative examples of this disclosure. Figure 6 This is a comparison of the stress amplitude of the cover in the mold unit involved in the embodiments and comparative examples of this disclosure.

[0036] First, such as Figure 5 As shown, the lid of Example 1 and the lid of Comparative Example 1 underwent thermal expansion only when the lid was set to 600°C. However, since the mold was set as a rigid body, the lid could not thermally expand in the left-right direction. At this time, when the thickness was uniform as in the lid of Comparative Example 1, the lid could not deform. On the other hand, when the thickness of the central part was reduced by providing a recess in the lower central part as in the lid of Example 1, the lid deformed in the upward direction.

[0037] Next, both the lid of Example 1 and the lid of Comparative Example 1 contracted horizontally as the lid temperature decreased. At this time, since the upper periphery of the lid was fixed to the mold, only the lower side of the lid contracted, resulting in the lid bulging upwards and deforming as a whole. Here, during deformation, the lid of Example 1, which has a recess, deformed more significantly than the lid of Comparative Example 1. This demonstrates that the recess formed in the lid promotes elastic deformation of the lid.

[0038] In addition, such as Figure 6 As shown, the stress amplitude of the lid is 1,203 MPa in Example 1 and 1,231 MPa in Comparative Example 1. Therefore, it is demonstrated that the stress amplitude of the lid can be mitigated by forming a recess in the lid. Furthermore, 1,203 MPa and 1,231 MPa are calculated using Equation 1 above.

[0039] As explained above, the mold unit according to the embodiments of this disclosure has a cover with a recess, which promotes elastic deformation of the cover, thereby mitigating the stress amplitude of the cover. Thus, a mold unit can be provided that can mitigate the stress amplitude of a cover used for temperature measurement, thereby extending the lifespan of the cover.

[0040] Next, the variations will be explained. In the above embodiment, the recess 31 (refer to) with its bottom surface bent concavely to the inner surface of the mold 2 is used. Figure 2 Specifically, the example of a recess 31 formed on the cover is described as a recess whose thickness gradually decreases from the outer periphery to the center, but it is not limited to this. That is, any recess formed in the cap can be any size, shape, or number of recesses that allow the cap to elastically deform during repeated thermal expansion due to molten metal contact and thermal contraction due to mold release agent spraying, thereby reducing the stress amplitude generated in the cap compared to the stress amplitude generated in the cap described in Patent Document 1. Furthermore, the location of these recesses is not limited to the outer surface of the mold 2. The specific size, shape, and number of such recesses 31 are difficult to determine using concrete numbers. However, for example, by using the specified software used in the stress analysis described above, it is possible to identify the size, shape, number, and location of recesses that allow the cap to elastically deform during repeated thermal expansion due to molten metal contact and thermal contraction due to mold release agent spraying, thereby reducing the stress amplitude generated in the cap compared to the stress amplitude generated in the cap described in Patent Document 1. Explanation of reference numerals in the attached figures

[0041] 1 mold unit 2 molds 21 Through Hole 3 lids 31 recess 311 Corner 4. Thermocouple wire 41. Turnback Section 5. Cylindrical components 6 Support components 7 Welding section

Claims

1. A mold unit comprising: A mold having a through hole extending from an outer surface to an inner surface, the inner surface defining a space into which molten material is injected; The cover, made of the same material as the mold, is fixed to the mold by welding in such a way that it blocks the end of the mold on the inner surface side in the through hole; Thermocouple wire has a folded-back portion, and when it passes through the through hole, the front end of the folded-back portion is fixed to the outer surface of the mold in the cover. A cylindrical component, while passing through the through hole, covers the thermocouple wire; as well as A support component provides support for the cylindrical component. The cylindrical component is fixed between the cover and the support component. The through hole and the cover do not contact each other in the area outside the welded part. The cover has a concave bottom surface that is curved, so that the cover can easily undergo elastic deformation when it expands or contracts with heat.

2. The mold unit according to claim 1, wherein, The recess has rounded corners at its corners.

3. The mold unit according to claim 1, wherein, The stress amplitude of the cover is smaller than that of a flat-plate cover.

4. The mold unit according to claim 1, wherein, The recess is formed in the cover on the outer surface side of the mold.

5. The mold unit according to claim 1 or 2, wherein, The depth of the recess is 10% to 25% of the thickness of the cover.

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