Radiation reducing structure

Abstract

To provide a radiation reduction structure capable of improving a working environment around a mold device which tends to become high in temperature.SOLUTION: The radiation reducing structure is related to a mold apparatus for molding a rubber product equipped with a heating source. An aluminum plate 10 is provided between at least a part of a mold device and a worker W so as to shield both of them. The 10a of the outer face of the aluminum plate 10 is constituted as a smooth face having a predetermined roughness or less, and is formed in a corrugated shape in which an angle θ formed by adjacent faces 1113 is an obtuse angle.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a radiation reduction structure, and more particularly to a radiation reduction structure for a mold device for molding rubber products. [Background technology]

[0002] In recent years, measures to prevent heatstroke have become an urgent issue in factories and other places, but because rubber products are molded by injecting material into molds heated to approximately 200°C, the area around the mold device where rubber products are molded is prone to becoming hot due to the effects of heat conduction transmitted through the air. Therefore, measures have traditionally been taken to maintain appropriate temperatures and humidity levels in the work space within the factory, including the area around the mold device, using air conditioners and other devices.

[0003] However, radiant heat is generated when electromagnetic waves (infrared rays) emitted by a heated substance hit an object. Unlike conductive heat, which is transmitted through the air, radiant heat is transmitted directly to the worker, and therefore cannot be alleviated by cool air from an air conditioner. Furthermore, molds are prone to radiating heat due to high temperatures of approximately 200°C and discoloration caused by gases emitted from rubber materials. Therefore, workers molding rubber products near the molding equipment may experience a rise in body temperature due to exposure to infrared rays, which can make them uncomfortable.

[0004] To alleviate the discomfort felt by workers, it is conceivable to apply a heat insulating paint to the mold apparatus or to cover the mold apparatus with a heat insulating material, etc. However, since the materials of heat insulating paint and heat insulating material have a high "emissivity," which indicates the ease with which heat is radiated, these measures, although they lower the surface temperature of the mold apparatus itself, generate a lot of infrared rays from the surface of the mold apparatus coated with the heat insulating paint, etc., which increases the discomfort felt by workers.

[0005] Therefore, for example, Patent Document 1 discloses a technique for enclosing a heat source such as a cylinder in a plastic injection molding machine with an equipment heat shield cover made of a metal plate attached with a material that has high reflectivity against radiant heat. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-008775 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, the above-mentioned Patent Document 1 only specifies "a material with high reflectivity against radiant heat," but it is known that even "the same material" can have different emissivity depending on the condition of the outer surface, such as the above-mentioned "discoloration." Furthermore, while equipment heat shielding covers naturally generate heat due to the influence of heat sources, Patent Document 1 makes no mention of how to deal with infrared rays emitted from the "material with high reflectivity against radiant heat" toward workers. In these respects, Patent Document 1 leaves room for improvement.

[0008] The present invention has been made in consideration of these points, and its object is to provide a radiation reduction structure that can improve the working environment around a mold device that is prone to becoming hot. [Means for solving the problem]

[0009] In order to achieve the above object, the radiation reduction structure according to the present invention is designed to reduce infrared rays transmitted from the mold device to the worker.

[0010] Specifically, the present invention is directed to a radiation reduction structure for a mold apparatus for molding rubber products, which is equipped with a heat source.

[0011] This radiation reduction structure is characterized in that a metal plate is provided between at least a portion of the mold device and the worker to provide a barrier between the two, and the outer surface of the metal plate is configured as a smooth surface with a surface roughness of a predetermined value or less, and is formed into a wave-shaped shape with adjacent surfaces forming an obtuse angle.

[0012] First of all, "radiation" is the phenomenon in which a hot substance emits infrared rays, and "radiant heat" is the heat generated when the infrared rays (electromagnetic waves) emitted by a substance hit an object. The amount of infrared rays emitted and the amount of heat generated when infrared rays hit an object vary depending on the emissivity (ease of heat radiation) of each substance.

[0013] More specifically, according to the law of conservation of energy, when infrared light hits an object, the sum of the reflectance, transmittance, and absorptance is 1, but if the object's transmittance is sufficiently small, the sum of the reflectance and absorptance can be considered to be 1.

[0014] Here, according to Kirchhoff's law, emissivity is equal to absorptivity, so if the transmittance is sufficiently small, the sum of reflectivity and emissivity can be considered to be 1. In other words, for a material with sufficiently small transmittance, the lower the reflectivity, the higher the emissivity (radiant heat), and conversely, the higher the reflectivity, the lower the emissivity (radiant heat). Generally, metals, except when extremely thin, have sufficiently low transmittance, and smooth surfaces tend to have lower emissivity than rough surfaces.

[0015] Based on the above, with this configuration, the outer surface of the metal plate provided between at least some of the components of the heated mold apparatus (e.g., the heat source, the mold, etc.) and the worker is a smooth surface with a surface roughness of a predetermined value or less, so that both are blocked by the metal plate, which has a high reflectivity and a low emissivity. Therefore, the infrared rays emitted from the mold apparatus are reflected by the metal plate toward the mold apparatus, and the infrared rays transmitted to the worker from the metal plate heated by the infrared rays emitted from the mold apparatus can be reduced.

[0016] If the metal plate installed to shield the mold device from the worker is flat, the infrared rays emitted from the heated metal plate will be emitted in a direction perpendicular to the flat metal plate, in other words, toward the worker who is positioned opposite the metal plate (mold device). In this regard, in the present invention, the metal plate is formed into a wave-shaped shape with adjacent surfaces forming an obtuse angle, so that the infrared rays emitted from the metal plate can be dispersed in different directions, reducing the infrared rays transmitted to the worker.

[0017] As described above, this radiation reduction structure has a simple configuration in which a corrugated metal plate with a smooth outer surface is provided to shield at least some of the parts that make up the mold device from the worker, thereby reducing the infrared rays transmitted from the mold device to the worker, thereby reducing the heat felt by the worker and improving the working environment around the mold device.

[0018] In the radiation reducing structure, the metal plate may be made of aluminum.

[0019] With this configuration, the metal plate is made of aluminum, which is cheaper than precious metals, which have a low emissivity but are expensive, and has a lower emissivity than iron, copper, etc., so it is possible to reliably improve the working environment around the mold device while suppressing cost increases.

[0020] Furthermore, in the radiation reducing structure, the angle between adjacent surfaces in the waveform may be set in the range of 90 to 155 degrees.

[0021] According to this configuration, the angle between adjacent surfaces in the waveform shape is set in the range of 90 to 155 degrees, which is an obtuse angle that has a particularly high dispersion effect, thereby more reliably improving the working environment around the mold device.

[0022] In the radiation reducing structure, the angle between adjacent surfaces of the corrugated shape may be set in the range of 95 to 115 degrees or 139 to 155 degrees.

[0023] According to this configuration, the angle between adjacent surfaces in the wavy shape is set to the range of 95 to 115 degrees or 139 to 155 degrees, which has a particularly high dispersion effect within the range of 90 to 155 degrees, thereby more reliably improving the working environment around the mold device.

[0024] In the radiation reduction structure, the metal plate may be attached to the mold device.

[0025] With this configuration, since the metal plate is attached to the mold device, it is possible to omit support structures for supporting the metal plate, compared to, for example, cases where the metal plate is provided at a position away from the mold device, thereby reducing cost increases.

[0026] Furthermore, even when the metal plate is attached to the mold device, since the metal plate is formed into a corrugated shape, the contact area with the heat source, mold, etc. can be made smaller than, for example, a flat metal plate. Therefore, the temperature rise of the metal plate itself due to heat conduction from the mold device can be suppressed, and this makes it possible to suppress the temperature rise due to heat conduction in the space between the metal plate and the worker, and the increase in infrared rays emitted from the metal plate.

[0027] As a result, the working environment around the mold device can be reliably improved while suppressing increases in costs.

[0028] In each of the above configurations, a corrugated metal plate with a smooth outer surface is provided to reduce the infrared rays transmitted from the mold device to the worker, but the radiation reduction structure may also be applied to the mold device itself.

[0029] Specifically, the present invention is a radiation reduction structure for a mold apparatus for molding rubber products, which is equipped with a heat source, characterized in that the outer surface of at least a portion of the mold apparatus that faces the worker's working position is configured as a smooth surface with a surface roughness of a predetermined value or less, and is formed in a wavy shape with an obtuse angle between adjacent surfaces.

[0030] As mentioned above, the emissivity of the outer surface of a heated material generally tends to be lower when it is smooth than when it is rough. With this configuration, the outer surface facing the worker's working position in at least some of the parts that make up the mold device is configured as a smooth surface with a surface roughness that is below a predetermined value, thereby reducing the infrared rays emitted from the mold device itself (or more precisely, from some of the parts themselves).

[0031] Furthermore, the outer surface of at least some of the parts constituting the mold device that faces the worker's working position is formed in a wave-shaped form with adjacent surfaces forming an obtuse angle, thereby dispersing the infrared rays emitted from the mold device itself in different directions, further reducing the infrared rays transmitted to the worker. [Effects of the Invention]

[0032] As described above, the radiation reduction structure according to the present invention can improve the working environment around the mold device, which is prone to high temperatures. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a schematic view showing a mold device to which a radiation reduction structure according to a first embodiment of the present invention is applied. [Figure 2] 1 is a side view seen from the working position side, showing a mold device to which a radiation reduction structure is applied in a simplified manner. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 1 is a diagram for explaining the infrared rays emitted from a metal plate having a waveform (obtuse angle). [Figure 5]1 is a diagram illustrating infrared rays emitted from a flat metal plate. FIG. [Figure 6] FIG. 1 is a diagram for explaining infrared rays emitted from a metal plate having a waveform (acute angle). [Figure 7] FIG. 2 is a diagram for schematically explaining Test 1 conducted to confirm the radiation reduction effect of the radiation reduction structure. [Figure 8] FIG. 10 is a side view seen from the working position side, simply showing a mold apparatus to which a radiation reduction structure according to a second embodiment of the present invention is applied. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 10 is a schematic view showing a mold device to which a radiation reduction structure according to another embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0035] (Embodiment 1) FIG. 1 is a schematic diagram showing a mold apparatus 1 to which the radiation reduction structure according to this embodiment is applied. Reference numeral 2 in FIG. 1 denotes a mounting table for adjusting the height of the mold apparatus 1 to a height suitable for the work of a worker W. This radiation reduction structure improves the work environment around the mold apparatus 1 by reducing electromagnetic waves (infrared rays) transmitted from the mold apparatus 1 to the worker W for molding a rubber product (not shown). In this mold apparatus 1, as shown in FIG. 1, the worker W, who is positioned on one side of the mold apparatus 1 (the right side of FIG. 1), performs the work of molding the rubber product. In the following description, the one side of the mold apparatus 1 on which the worker W is positioned will also be referred to as the "work position side."

[0036] FIG. 2 is a simplified side view of a mold apparatus 1 to which a radiation reduction structure is applied, viewed from the work position side. To make the drawing easier to see, FIG. 2 omits the illustration of an elevating mechanism for elevating an upper mold 7, heat insulating materials, and the like. As shown in FIG. 2, the mold apparatus 1 includes an upper heat source 3, a lower heat source 5, an upper mold 7, and a lower mold 9, and is configured to mold a rubber product by injecting a rubber material between the upper mold 7 heated to approximately 200°C by the upper heat source 3 and the lower mold 9 heated to approximately 200°C by the lower heat source 5. The upper heat source 3, the lower heat source 5, the upper mold 7, and the lower mold 9 are made of steel.

[0037] For this reason, the area around the mold device 1 is prone to become hot due to the influence of heat conduction transmitted through the air, making it a space where the worker W is likely to feel hot. Therefore, in order to alleviate the discomfort of the worker W, it is conceivable to use an air conditioner or the like to maintain the area around the mold device 1 at an appropriate temperature and humidity, or to apply a heat insulating paint to the mold device 1.

[0038] However, radiant heat is generated when electromagnetic waves (infrared rays) emitted by a heated substance strike an object. Unlike conductive heat, which is transmitted through the air, radiant heat is transmitted directly to the worker W and is therefore not mitigated by cool air from an air conditioner or similar device. Furthermore, insulating paints generally have a high emissivity (emissivity), which indicates the ease of heat radiation (e.g., 0.92–0.96 at a temperature of 93°C). Therefore, applying insulating paint to the mold apparatus 1 reduces the surface temperature of the mold apparatus 1 itself, but generates more infrared rays from the coated surface of the mold apparatus 1. Additionally, the surface of the mold apparatus 1 is prone to radiation due to high temperatures of approximately 200°C and discoloration caused by gases generated by the rubber material. Therefore, workers W performing rubber product molding work near the mold apparatus 1 may experience increased body temperature and discomfort when exposed to infrared radiation (IR) (see Figure 4).

[0039] Therefore, in this embodiment, a radiation reduction structure is employed in the mold apparatus 1 to reduce infrared rays IR transmitted from the mold apparatus 1 to the worker W. Specifically, as shown in FIG. 1, a metal plate 10 is provided between the upper heat source 3 and the upper mold 7 (at least a portion thereof) constituting the mold apparatus 1 and the worker W so as to shield them from each other. More specifically, as shown in FIG. 2, the metal plate 10 is attached to the mold apparatus 1 so as to cover the working position side of the upper heat source 3 and the upper mold 7. Such a metal plate 10 will be described in detail below.

[0040] -Metal plate material and outer surface- First of all, radiation is the phenomenon in which a hot substance emits infrared rays, and radiant heat is the heat generated when the infrared rays (electromagnetic waves) emitted by a substance hit an object. The amount of infrared rays emitted and the amount of heat generated when infrared rays hit an object vary depending on the emissivity (ease of heat radiation) of each substance.

[0041] More specifically, according to the law of conservation of energy, when infrared rays hit an object, the sum of the reflectance, transmittance, and absorptance is 1, but if the transmittance of the object is sufficiently small, the sum of the reflectance and absorptance can be considered to be 1. Generally, metals can be said to have sufficiently small transmittance, except when they are extremely thin, so the sum of the reflectance and emissivity of metal plate 10 can be considered to be 1.

[0042] According to Kirchhoff's law, emissivity is equal to absorptivity, and therefore the sum of the reflectivity and emissivity of the metal plate 10 can be considered to be 1. In other words, in the metal plate 10, the reflectivity and emissivity are related in such a way that the smaller the reflectivity, the larger the emissivity (radiant heat), and conversely, the larger the reflectivity, the smaller the emissivity (radiant heat).

[0043] Table 1 below shows examples of the emissivity (emissivity) of common metals depending on their surface conditions and temperature ranges.

[0044] [Table 1]

[0045] As shown in Table 1, the emissivity of metals is generally lower than that of the above-mentioned heat insulating paints (emissivity 0.92 to 0.96). Also, as can be seen from Table 1, smooth metal surfaces tend to have lower emissivity than rough metal surfaces.

[0046] Therefore, in the radiation reduction structure of this embodiment, an aluminum metal plate (hereinafter also referred to as "aluminum plate 10") is used as the metal plate 10, and the outer surface 10a of the aluminum plate 10 is configured to be a smooth surface. Specifically, the outer surface 10a of the aluminum plate 10 is polished to form a smooth surface with a surface roughness of 1 μm (predetermined value) or less.

[0047] In this way, the outer surface 10a of the aluminum plate 10, which is provided between the heated upper heat source 3 and upper mold 7 and the worker W, is a smooth surface with a surface roughness of a predetermined value or less, and therefore both are blocked by the aluminum plate 10, which has a low emissivity and a high reflectivity. Therefore, the infrared rays IR emitted from the upper heat source 3 and upper mold 7 are reflected by the aluminum plate 10 toward the mold device 1, and it is possible to reduce the infrared rays IR transmitted from the heated aluminum plate 10 to the worker W by the infrared rays IR emitted from the upper heat source 3 and upper mold 7.

[0048] Specifically, the upper mold 7 made of steel and the like are discolored (oxidized) due to the high temperature of approximately 200°C and the effects of gases generated from the rubber material. However, as shown in Table 1, by using an aluminum plate 10 (emissivity 0.04 to 0.08) whose outer surface 10a is smooth (normally polished), it is possible to reduce the emissivity to approximately 1 / 20 to 1 / 10 compared to the oxidized surface of steel (emissivity 0.79).

[0049] Furthermore, since the aluminum plate 10 is cheaper than expensive precious metals such as silver and gold, which have low emissivity, and has a lower emissivity than iron or copper, it is possible to prevent costs from increasing.

[0050] -Metal plate shape- Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2, and Fig. 4 is a diagram illustrating infrared rays IR emitted from a corrugated (obtuse angle) aluminum plate 10. Fig. 5 is a diagram illustrating infrared rays IR emitted from a flat aluminum plate 110, and Fig. 6 is a diagram illustrating infrared rays IR emitted from a corrugated (acute angle) aluminum plate 210. Note that in Figs. 4 to 6, for ease of viewing, the die device 1 to which the aluminum plates 10, 110, and 210 are attached is omitted, and the sizes of the aluminum plates 10, 110, and 210 are exaggerated.

[0051] Here, if the aluminum plate 110 arranged to block the mold device 1 and the worker W is flat as shown in Figure 5, the infrared rays IR emitted from the heated aluminum plate 110 will be emitted in a direction perpendicular to the outer surface 110a of the flat aluminum plate 110, in other words, toward the worker W who is positioned opposite the aluminum plate 110 (mold device 1).

[0052] On the other hand, if the aluminum plate 210 provided so as to shield the mold device 1 from the worker W has a wave shape in which the angle θ1 formed by the adjacent surfaces 211, 213 is an acute angle, as shown in Fig. 6, the infrared rays IR emitted from the aluminum plate 210 will be repeatedly reflected in a direction perpendicular to the outer surface 210a of the aluminum plate 210, in other words, between the adjacent surfaces 211, 213. As a result, the infrared rays IR will accumulate on the outer surface 210a of the aluminum plate 210, and a larger amount of infrared rays IR will be emitted toward the worker W than in the case of a flat aluminum plate 110.

[0053] Therefore, in the radiation reduction structure of this embodiment, the aluminum plate 10, whose outer surface 10a is a smooth surface, is formed into a wave-shaped shape in which the angle θ between adjacent surfaces 11 and 13 is an obtuse angle, as shown in Figure 3.

[0054] In this way, the aluminum plate 10 is formed into a corrugated shape in which the angle θ between the adjacent surfaces 11, 13 is an obtuse angle, and therefore the infrared rays IR emitted from the aluminum plate 10 can be dispersed in a direction perpendicular to the outer surface 10a of the aluminum plate 10, in other words, in different directions, as shown in Fig. 4. This makes it possible to reduce the amount of infrared rays IR transmitted to the worker W compared to the case of a flat aluminum plate 110 or the case of a corrugated aluminum plate 210 in which the angle θ1 between the adjacent surfaces 211, 213 is an acute angle.

[0055] The angle θ between adjacent surfaces 11 and 13 in the corrugated shape of aluminum sheet 10 is preferably set in the range of 90 to 155 degrees, and more preferably in the range of 95 to 115 degrees or 139 to 155 degrees. Thus, by setting the angle θ between adjacent surfaces 11 and 13 in the corrugated shape to the range of 90 to 155 degrees, which is an obtuse angle that provides a particularly high dispersion effect, the working environment around mold apparatus 1 can be more reliably improved. Furthermore, by setting the angle θ between adjacent surfaces 11 and 13 in the corrugated shape to the range of 95 to 115 degrees or 139 to 155 degrees, which is an obtuse angle that provides a particularly high dispersion effect, the working environment around mold apparatus 1 can be even more reliably improved.

[0056] Additionally, in this embodiment, since the aluminum plate 10 is attached to the mold apparatus 1, a support structure for supporting the aluminum plate 10 can be omitted, compared to, for example, a case where the aluminum plate 10 is provided at a position distant from the mold apparatus 1 (see FIG. 10 ), thereby suppressing increases in costs. Even when the aluminum plate 10 is directly attached to the mold apparatus 1, the aluminum plate 10 is formed in a corrugated shape, so the contact area with the upper heating source 3 and the upper mold 7 can be reduced compared to, for example, a flat aluminum plate 110. Therefore, the temperature rise of the aluminum plate 10 itself due to heat conduction from the mold apparatus 1 can be suppressed by approximately 20°C compared to, for example, a case where a flat aluminum plate 110 is attached. This suppresses the temperature rise due to heat conduction in the space between the aluminum plate 10 and the worker W and the increase in infrared rays IR emitted from the aluminum plate 10.

[0057] -Example- <Test 1> Next, Test 1 conducted to confirm the radiation reduction effect of the radiation reduction structure of this embodiment will be described. Fig. 7 is a diagram schematically illustrating Test 1 conducted to confirm the radiation reduction effect of the radiation reduction structure.

[0058] Test 1 was performed by placing sample 20 on a lower heating source 5 (the lower hot plate of an NTV-5 molding machine) heated to 200°C, as shown in Figure 7, and placing a thermal environment meter 21 (Kyoto Electronics Manufacturing Co., Ltd., product name: WBGT-102) 10 cm away from sample 20. After 5 minutes, the black globe temperature was measured and compared. The black globe temperature is a temperature that is highly correlated with perceived temperature and is measured taking into account radiant heat from heating elements, direct sunlight, and the ground. To prevent the measurement from being affected by external radiation, the test space containing lower heating source 5 and thermal environment meter 21 was enclosed by an aluminum shielding cover 23.

[0059] In Test 1, the black globe temperature was measured for five samples: a corrugated aluminum plate 10 (Example) in which the angle θ between adjacent surfaces 11, 13 was 130° (obtuse angle) as sample 20; a lower hot plate substrate without sample 20 (Comparative Example 1); a flat aluminum plate 110 (Comparative Example 2); a corrugated aluminum plate 210 (Comparative Example 3) in which the angle θ between adjacent surfaces 211, 213 was 35° (acute angle); and a corrugated aluminum plate 20 (Comparative Example 4) in which the angle between adjacent surfaces was 65° (acute angle close to a right angle). In this Example and Comparative Examples 2 to 4, the aluminum plates used had smooth outer surfaces with a surface roughness of a predetermined value or less.

[0060] The measurement results are shown in Table 2 below. WBGT (Wet bulb globe temperature) is a value calculated based on the wet bulb temperature, black bulb temperature, and dry bulb temperature, and is used as a reference value for heatstroke risk, taking into account the effects of humidity and radiant heat in addition to air temperature. Dry bulb temperature is the so-called air temperature (air temperature).

[0061] [Table 2]

[0062] As shown in Table 2, this example, which uses an aluminum plate 10 whose outer surface 10a is configured as a smooth surface with a surface roughness of a predetermined value or less and whose corrugated shape is formed with an obtuse angle θ between adjacent surfaces 11 and 13, was confirmed to be able to reduce both the black globe temperature and WBGT compared to Comparative Example 1, which does not use an aluminum plate, Comparative Example 2, which uses a flat aluminum plate 110, and Comparative Examples 3 and 4, which use an aluminum plate 210 with an acute corrugation angle. Furthermore, for reference, this example was also confirmed to be able to reduce the dry bulb temperature compared to Comparative Examples 1 to 4. It was also confirmed that, even with the same corrugated shape, the aluminum plate 210 with an acute corrugation angle, which is thought to accumulate infrared rays IR on the outer surface 210a, had higher black globe temperature and WBGT than the flat aluminum plate 110.

[0063] As described above, the radiation reduction structure of this embodiment has a simple configuration in which an aluminum plate 10 with a corrugated shape (obtuse angle) and a smooth outer surface 10a is provided to shield at least some of the parts that make up the mold device 1 from the worker W, thereby reducing the infrared rays IR transmitted from the mold device 1 to the worker W, thereby reducing the heat felt by the worker W and improving the working environment around the mold device 1.

[0064] <Test 2> Next, a second test will be described, which was conducted to confirm the range of obtuse angles that provides a particularly high dispersion effect in the radiation reduction structure of this embodiment.

[0065] Test 2 was conducted in the same manner as Test 1, using the method shown in FIG. 7 above. In Test 2, the black globe temperature was measured using aluminum plates 10 in which the angle θ between adjacent surfaces 11, 13 was formed into different corrugated shapes within the obtuse angle range. The measurement results are shown in Table 3 below. The temperatures in Table 3 indicate how much the black globe temperature was reduced compared to a flat aluminum plate 110.

[0066] [Table 3]

[0067] As shown in Table 3, it was confirmed that when the angle θ between the adjacent surfaces 11 and 13 was within the range of 96 to 151 degrees, it was possible to reduce the black globe temperature by approximately -1.0 (°C) compared to the flat aluminum plate 110. In particular, it was confirmed that when the angle θ between the adjacent surfaces 11 and 13 was within the range of 96 to 112 degrees and within the range of 139.9 to 151 degrees, it was possible to reduce the black globe temperature by approximately -2.0 (°C) compared to the flat aluminum plate 110.

[0068] (Embodiment 2) This embodiment differs from the first embodiment in that no metal plate is provided between the mold device and the worker W to block the two. The following will mainly explain the differences from the first embodiment.

[0069] Fig. 8 is a side view seen from the working position side, which shows a mold device 31 to which the radiation reduction structure according to this embodiment is applied, and Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Note that in Fig. 8, for ease of viewing, an elevating mechanism for elevating the upper mold 37, heat insulating materials, etc. are not shown.

[0070] 8, mold apparatus 31 includes an upper heating source 33, a lower heating source 35, an upper mold 37, and a lower mold 39, and is configured to mold a rubber product by injecting a rubber material between upper mold 37 heated to approximately 200°C by upper heating source 33 and lower mold 39 heated to approximately 200°C by lower heating source 35, similar to mold apparatus 1 of embodiment 1. Also, similar to mold apparatus 1 of embodiment 1, upper heating source 33, lower heating source 35, upper mold 37, and lower mold 39 are made of steel.

[0071] However, unlike the first embodiment, the radiation reduction structure of this embodiment does not provide a metal plate between the mold device 31 and the worker W, but rather, as shown in Fig. 8, outer surfaces 33a, 35a, 37a, and 39a of the mold device 31 itself, which face the working position of the worker W, are configured as smooth surfaces with a surface roughness of a predetermined value or less, and as shown in Fig. 9, the outer surface 33a of the upper heat source 33 is formed into a waveform shape in which the angle θ0 formed by adjacent surfaces 33b and 33c is an obtuse angle. Although not shown, the outer surfaces 35a, 37a, and 39a of the lower heat source 35, upper mold 37, and lower mold 39 are also formed into a waveform shape in which the angle formed by adjacent surfaces is an obtuse angle, similar to the upper heat source 33.

[0072] As described above, in a typical mold apparatus, the steel upper and lower heating sources, upper and lower dies, and lower dies are discolored (oxidized) due to high temperatures of approximately 200°C and the effects of gases generated from rubber materials. As shown in Table 1, the polished surface of steel (emissivity 0.07 to 0.11) has a lower emissivity than the oxidized surface of steel (emissivity 0.79). Therefore, the radiation reduction structure of this embodiment, in which the outer surfaces 33a, 35a, 37a, and 39a of the mold apparatus 31 facing the working position of the worker W are smooth surfaces with a surface roughness of a predetermined value or less, can reduce infrared rays IR emitted from the mold apparatus 31 itself.

[0073] Furthermore, the outer surfaces 33a, 35a, 37a, and 39a of the mold device 31 that face the working position of the worker W are formed in a wave-shaped form in which the angle θ0 between adjacent surfaces 33b and 33c is an obtuse angle. As a result, as in embodiment 1, the infrared rays IR emitted from the mold device 31 itself can be dispersed in different directions, thereby reducing the infrared rays IR transmitted to the worker W.

[0074] (Other embodiments) The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main characteristics thereof.

[0075] In each of the above embodiments, the present invention is applied to mold devices 1, 31 that are equipped with heat sources 3, 5, 33, 35 separate from molds 7, 9, 37, 39, but this is not limited to this, and the present invention may also be applied to, for example, a mold device that has a heater built into the mold.

[0076] Furthermore, in the above embodiment 1, the aluminum plate 10 is attached to the mold device 1 so as to cover the working position side of the upper heating source 3 and the upper mold 7, but this is not limited to this. For example, as shown in Figure 10, the aluminum plate 10 may be positioned at a position away from the mold device 1 using a support stand 25 for supporting the aluminum plate 10.

[0077] Furthermore, in the first embodiment, an aluminum plate 10 is used as the metal plate 10, but the present invention is not limited to this, and a metal plate 10 made of a material other than aluminum may be used.

[0078] Furthermore, in the above-mentioned embodiment 1, an aluminum plate 10 is provided to cover the upper heating source 3 and the upper mold 7, which are among the parts that make up the mold device 1, and in the above-mentioned embodiment 2, a radiation reduction structure is applied to the entire outer surfaces 33a, 35a, 37a, 39a that face the work position side of the mold device 31, but this is not limited to this, and the radiation reduction structure may be applied to any part as long as it is applied to at least some of the parts that make up the mold devices 1 and 31.

[0079] Furthermore, in the above embodiment 2, the upper heating source 33, the lower heating source 35, the upper mold 37 and the lower mold 39 are made of steel, but this is not limited to this, and the mold device 31 may also be made of a metal with a lower emissivity than steel.

[0080] As such, the above-described embodiments are merely examples in all respects and should not be interpreted as limiting. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0081] According to the present invention, the working environment around the mold apparatus, which is prone to become hot, can be improved, and therefore it is extremely useful when applied to a mold apparatus for molding rubber products. [Explanation of symbols]

[0082] 1,31 Mold equipment 3,33 Upper heating source (heating source) 5,35 Lower heating source (heating source) 10 Aluminum plate (metal plate) 10a outer surface 11,13 Adjacent faces 33a, 35a Outer surface of the heat source 33b, 33c Adjacent surfaces 37a, 39a Outer surface of mold W Worker θ,θ0 Angle between adjacent surfaces

Claims

1. A radiation reduction structure for a mold device for molding a rubber product, comprising a heat source, a metal plate is provided between at least a part of the mold device and the worker so as to separate them from each other; The radiation reduction structure is characterized in that the outer surface of the metal plate is configured as a smooth surface with a surface roughness of a predetermined value or less, and is formed into a wave-shaped shape with adjacent surfaces forming an obtuse angle.

2. In the radiation reduction structure according to claim 1, The radiation reduction structure is characterized in that the metal plate is made of aluminum.

3. In the radiation reduction structure according to claim 1, A radiation reduction structure characterized in that the angle between adjacent surfaces in the wave shape is set in the range of 90 to 155 degrees.

4. In the radiation reduction structure according to claim 3, A radiation reduction structure characterized in that the angle between adjacent surfaces of the wave shape is set in the range of 95 to 115 degrees or 139 to 155 degrees.

5. In the radiation reduction structure according to claim 1, The metal plate is attached to the mold device.

6. A radiation reduction structure for a mold device for molding a rubber product, comprising a heat source, A radiation reduction structure characterized in that the outer surface facing the worker's working position in at least some of the parts constituting the mold device is configured as a smooth surface with a surface roughness of a predetermined value or less, and is formed in a wave-shaped shape with an obtuse angle between adjacent surfaces.

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