Heating device

Abstract

This heating device has a heating plate and a plurality of heaters. The heating plate has a heating surface and a rear surface in relation to the heating surface. In the heating plate, a hole extending in the thickness direction is formed in the center of the heating surface, and a plurality of recesses are formed at least around a region of the rear surface corresponding to the hole. Each of the plurality of heaters is inserted into a respective recess of the plurality of recesses.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION The disclosed embodiments relate to a heating device. [Background technology]

[0002] Patent document 1 discloses a heating device that includes a plate-shaped mold having a hole extending in the thickness direction in the center of the heating surface and multiple horizontal holes formed on the side to avoid the hole, and multiple heaters inserted into each of the horizontal holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-11224 Summary of the Invention

[0004] A heating device according to one aspect of the embodiment includes a heating plate and a plurality of heaters. The heating plate has a heating surface and a back surface opposite the heating surface. The heating plate has a hole formed in the center of the heating surface extending in the thickness direction, and a plurality of recesses formed in the back surface around at least an area corresponding to the hole. The plurality of heaters are inserted into the plurality of recesses, respectively. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a side view of a heating device according to an embodiment. [Figure 2] FIG. 2 is a top view of the heating device according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a heating device according to a first modified example of the embodiment. [Figure 5] FIG. 5 is a cross-sectional view of a heating device according to a second modification of the embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a heating device according to a third modification of the embodiment. [Figure 7] FIG. 7 is a cross-sectional view of a heating device according to a fourth modification of the embodiment. [Figure 8] FIG. 8 is a top view of a heating device according to a fifth modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] Hereinafter, embodiments of the heating device disclosed in the present application will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0007] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] <Embodiment> Fig. 1 is a side view of the heating device 100 according to the embodiment. Fig. 2 is a top view of the heating device 100 according to the embodiment. In the following description, when the heating device 100 is brought into contact with the object to be heated, the surface facing the object to be heated is referred to as the "upper surface," and the surface facing the opposite side to the object to be heated is referred to as the "lower surface." However, the heating device 100 may be used, for example, upside down, or in any position.

[0009] As shown in FIG. 1, the heating device 100 includes a heating plate 110, a plurality of heaters 120, and a fixing plate .

[0010] The heating plate 110 is, for example, a metal plate-like member, and has an upper surface 110a that can come into contact with an object to be heated. That is, the upper surface 110a of the heating plate 110 serves as a heating surface (an example of a first surface) that heats the object to be heated. The upper surface 110a is used, for example, to heat a mold, which is an example of an object to be heated. A plurality of recesses 113 are formed on a lower surface (an example of a second surface) 110b of the heating plate 110, which is on the opposite side to the heating surface (see FIG. 3).

[0011] The heaters 120 are, for example, ceramic heaters having a ceramic body and a heating resistor located inside the ceramic body. By using ceramic heaters as the heaters 120, it is possible to reduce seizure between the heating plate 110, which is made of metal, and the heaters 120.

[0012] The length of the heater 120, i.e., the length of the ceramic body, can be, for example, approximately 1 mm to 200 mm. The outer dimensions of the ceramic body can be, for example, approximately 0.5 mm to 100 mm. The shape of the heater 120, i.e., the shape of the ceramic body, is not limited to a cylindrical shape, but can also be, for example, an elliptical cylindrical shape or a rectangular cylindrical shape. The ceramic body is made of, for example, an insulating ceramic. Examples of materials that can be used for the ceramic body include oxide ceramics, nitride ceramics, and carbide ceramics. The heating resistor is a component that generates heat when a current flows through it. The heating resistor may include, for example, a high-resistance conductor containing tungsten, molybdenum, or the like. The dimensions of the heating resistor can be, for example, a width of 0.1 mm to 5 mm, a thickness of 0.05 mm to 0.3 mm, and a total length of 1 mm to 500 mm. The heating resistor may also be made of, for example, conductive ceramic containing tungsten carbide. In this case, the thermal expansion difference between the ceramic body and the heating resistor can be reduced. This reduces the thermal stress between the ceramic body and the heating resistor, thereby improving the durability of the heater 120.

[0013] The heaters 120 are positioned in the recesses 113 of the heating plate 110. That is, the heaters 120 are inserted into the recesses 113, respectively, and are arranged perpendicular to the upper surface 110a of the heating plate 110, which is the heating surface.

[0014] In this way, by arranging the heaters 120 perpendicular to the heating surface of the heating plate 110, it is possible to reduce the variation in the distance between the heaters 120 and the heating surface, thereby improving the temperature uniformity within the upper surface 110a of the heating plate 110, which is the heating surface.

[0015] The fixing plate 130 is, for example, a metal plate-like member, and has a plurality of heaters 120 fixed thereto.

[0016] Next, the heating plate 110, the plurality of heaters 120, and the fixing plate 130 will be described in more detail with reference to Figures 2 and 3. Figure 3 is a cross-sectional view taken along line III-III in Figure 2. Note that Figure 2 shows a planar perspective view of the heating plate 110 seen from a direction perpendicular to the upper surface 110a. As shown in Figures 2 and 3, the heating device 100 is configured such that the plurality of heaters 120 are fixed to the fixing plate 130 and inserted into the plurality of recesses 113 of the heating plate 110, respectively.

[0017] The heating plate 110 has an upper surface 110a and a lower surface 110b. The upper surface 110a is a heating surface that heats an object to be heated, and the lower surface 110b is a surface opposite to the heating surface.

[0018] As shown in FIGS. 2 and 3, a hole 116 extending in the thickness direction of the heating plate 110 is formed in the center of the upper surface 110a. The hole 116 extends in the thickness direction of the heating plate 110 to a depth that does not penetrate the heating plate 110 from the upper surface 110a to the lower surface 110b. For example, the hole 116 extends to a position that reaches the heat insulating member 115, which is described below and is included in the heating plate 110. The cross-sectional shape of the hole 116 may be any shape. For example, the hole 116 shown in FIG. 3 has a cross-sectional shape with linear side surfaces. The diameter (width) of the hole 116 may be any diameter. For example, the hole 116 shown in FIG. 3 has a smaller diameter than each of the multiple recesses 113.

[0019] By forming a hole 116 in the center of the upper surface 110a of the heating plate 110, which is the heating surface, heat can be released from the center of the upper surface 110a to the atmosphere within the hole 116. That is, heat is less likely to escape from the center of the upper surface 110a to the atmosphere surrounding the heating plate 110 than from the periphery of the upper surface 110a. For this reason, the temperature of the center of the upper surface 110a of the heating plate 110 may be higher than that of the periphery. In contrast, by forming the hole 116 in the center of the upper surface 110a, heat can be released from the center of the upper surface 110a to the atmosphere within the hole 116, and the amount of heat released from the center of the upper surface 110a can be increased compared to the amount of heat released from the periphery of the upper surface 110a. This reduces the temperature difference between the center and periphery of the upper surface 110a.

[0020] A plurality of recesses 113 into which the plurality of heaters 120 are respectively inserted are formed around at least an area of ​​the lower surface 110b that corresponds to the hole 116. Specifically, the plurality of recesses 113 are formed at equal intervals along the periphery of at least an area of ​​the lower surface 110b that corresponds to the hole 116. In this embodiment, the plurality of recesses 113 are formed in a lattice pattern at equal intervals over the entire surface of the lower surface 110b.

[0021] In this way, by forming the plurality of recesses 113 at equal intervals along the periphery of at least the region of the lower surface 110b that corresponds to the hole 116, the plurality of heaters 120 can be evenly arranged along the circumferential direction of the hole 116 on the upper surface 110a. In other words, the plurality of heaters 120 are positioned around the hole 116 in a planar perspective view (see FIG. 2). This allows the region around the hole 116 to be evenly heated by the plurality of heaters 120 without causing a temperature difference along the circumferential direction of the hole 116 on the upper surface 110a of the heating plate 110. As a result, the heating device 100 according to this embodiment can improve the temperature uniformity around the hole 116 on the upper surface 110a, which is the heating surface.

[0022] The positions where the recesses 113 are formed are not limited to the positions shown in Fig. 2. For example, the recesses 113 may be formed concentrically around the region corresponding to the hole 116 on the entire surface of the lower surface 110b.

[0023] The heating plate 110 has a laminated structure in which a first plate member 111, a second plate member 112, and a heat insulating member 115 are laminated.

[0024] The first plate member 111 is a plate-like member having an upper surface 110a of the heating plate 110, which is the heating surface. The first plate member 111 is joined to the second plate member 112 by joining members 114, such as bolts, with a heat insulating member 115 disposed between the first plate member 111 and the second plate member 112. That is, the lower surface 111a of the first plate member 111 opposite the upper surface 110a is the joining surface that is joined to the second plate member 112. A cylindrical spacer member 170 made of, for example, ceramic with high heat insulating properties is provided on the outer periphery of the joining member 114. A plurality of recesses 111b are formed in the lower surface 111a of the first plate member 111 opposite the heating surface.

[0025] The second plate member 112 is a plate-like member having an upper surface 112a which serves as a joining surface to be joined to the joining surface of the first plate member 111, and a lower surface 110b located on the opposite side of the upper surface 112a. A plurality of through holes 112b are formed in the second plate member 112 at positions corresponding to the plurality of recesses 111b.

[0026] The heat insulating member 115 is located between the first plate member 111 and the second plate member 112. That is, the heat insulating member 115 is interposed between the first plate member 111 and the second plate member 112. The heat insulating member 115 is, for example, a sheet-like member made of heat insulating fiber, and has the function of limiting the transfer of heat from the first plate member 111 side to the second plate member 112 side. A plurality of through holes 115a are formed in the heat insulating member 115 at positions corresponding to the plurality of recesses 111b.

[0027] The material of the heat insulating member 115 is preferably, for example, ceramics having heat insulating properties. For example, oxide ceramics, nitride ceramics, carbide ceramics, or the like can be used as the material of the heat insulating member 115.

[0028] Each of the plurality of recesses 113 is formed by a corresponding one of the plurality of through holes 112b, a corresponding one of the plurality of through holes 115a, and a plurality of recesses 111b. That is, the inner surfaces of each of the through holes 112b, the inner surfaces of each of the through holes 115a, and the inner surfaces of each of the recesses 111b form the inner surface of each of the recesses 113, and the bottom surfaces of each of the recesses 111b form the bottom surfaces of each of the recesses 113. Then, with the plurality of heaters 120 inserted into the plurality of recesses 113, the tips 120a of the plurality of heaters 120 are positioned in the plurality of recesses 111b.

[0029] The fixing plate 130 has a plurality of fixing holes 130a at positions corresponding to the plurality of recesses 113. A plurality of heaters 120 are inserted into and fixed to the fixing holes 130a, respectively. Specifically, an internal thread is formed on a portion of the inner wall of each fixing hole 130a. Meanwhile, a cylindrical mounting member 121 is attached to the outer circumferential surface of each heater 120, and an external thread 121a is formed on a portion of the outer circumferential surface of the mounting member 121. When each heater 120 is inserted into each fixing hole 130a, the external thread 121a fits into the internal thread of each fixing hole 130a, thereby fixing the plurality of heaters 120 to the fixing plate 130.

[0030] The fixing plate 130 is disposed at a distance from the heating plate 110. As shown in FIGS. 2 and 3 , the fixing plate 130 is connected to the heating plate 110 (second plate member 112) by connecting members 131 such as bolts, with a gap formed between the fixing plate 130 and the heating plate 110. By separating the fixing plate 130 from the heating plate 110 in this manner, it is possible to reduce the temperature rise in the portions where the multiple heaters 120 are fixed to the fixing plate 130 (for example, portions where the mounting members 121 are attached). On the other hand, since the amount of heat removed from the heating plate 110 by the fixing plate 130 is reduced, it is possible to promote the temperature rise of the heating plate 110.

[0031] Furthermore, a spacer member 140 is disposed between the heating plate 110 and the fixed plate 130. The spacer member 140 is cylindrical and surrounds the portion of the connecting member 131 that is located between the heating plate 110 and the fixed plate 130, with both ends contacting the heating plate 110 and the fixed plate 130. By providing the spacer member 140 between the heating plate 110 and the fixed plate 130, the possibility of collision between the fixed plate 130 and the heating plate 110 can be reduced.

[0032] The spacer member 140 may be made of a metal such as stainless steel, which improves the durability of the spacer member 140 and allows the distance between the fixed plate 130 and the heating plate 110 to be maintained constant.

[0033] The material of the spacer member 140 may be, for example, a heat-resistant ceramic. For example, oxide ceramics, nitride ceramics, or carbide ceramics can be used as the material of the spacer member 140. This reduces the thermal expansion and contraction of the spacer member 140, thereby reducing wear of the spacer member 140.

[0034] The heaters 120 have base ends 120b positioned farther from the upper surface 110a of the heating plate 110 (the heating surface) than the lower surface of the fixing plate 130 opposite the heating plate 110. Power supply terminals 122, 123 that supply power to the heaters 120 are provided at the base ends 120b. In other words, the base ends 120b of the heaters 120 protrude in a direction away from the upper surface 110a of the heating plate 110 (the heating surface) than the lower surface of the fixing plate 130, and the power supply terminals 122, 123 are provided at the base ends 120b. By providing the power supply terminals 122, 123 at the base ends 120b that protrude in a direction away from the upper surface 110a of the heating plate 110 (the heating surface), the power supply terminals 122, 123 can be spaced farther from the heating surface. As a result, the power supply terminals 122, 123 can be protected from the heat of the heating surface.

[0035] <Modifications of the embodiment> Next, various modified examples of the embodiment will be described with reference to Figures 4 to 8. In the following description, the same components as those in the above-described embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0036] Fig. 4 is a cross-sectional view of a heating device 100 according to a first modified example of the embodiment. The heating device 100 shown in Fig. 4 differs from the heating device 100 shown in Figs. 1 to 3 mainly in the shape of the hole 116. Specifically, in the heating device 100 shown in Fig. 4, the hole 116 has a cross-sectional shape in which the diameter (width) on the upper surface 110a side, which is the heating surface, is smaller than the diameter on the lower surface 110b side, which is the back surface opposite to the heating surface. In this embodiment, the hole 116 has a cross-sectional shape in which the diameter on the upper surface 110a side is smaller than the diameter on the lower surface 110b side and the side surface is stepped.

[0037] In this way, by making the diameter of the hole 116 on the upper surface 110a side smaller than the diameter on the lower surface 110b side in the cross-sectional shape, it is possible to reduce a decrease in strength on the upper surface 110a side of the heating plate 110. That is, as the diameter of the hole 116 increases, the amount of heat dissipated from the center of the upper surface 110a to the atmosphere inside the hole 116 can be increased, but on the other hand, this may reduce the strength of the upper surface 110a side of the heating plate 110. Because the upper surface 110a, which is the heating surface, receives external force from the heating object when it comes into contact with the heating object, a decrease in strength on the upper surface 110a side of the heating plate 110 can cause a decrease in durability of the heating plate 110. In contrast, by making the diameter of the hole 116 on the upper surface 110a side smaller than the diameter on the lower surface 110b side in the cross-sectional shape, it is possible to relatively increase the strength of the upper surface 110a side of the heating plate 110. This reduces a decrease in strength on the upper surface 110a side of the heating plate 110, thereby improving the durability of the heating plate 110.

[0038] The cross-sectional shape of hole 116 may be various shapes as long as the diameter on the upper surface 110a side is smaller than the diameter on the lower surface 110b side. For example, hole 116 may have a cross-sectional shape in which the diameter on the upper surface 110a side is smaller than the diameter on the lower surface 110b side and the side surfaces are tapered or curved.

[0039] Fig. 5 is a cross-sectional view of a heating device 100 according to Modification 2 of the embodiment. The heating device 100 shown in Fig. 5 differs from the heating device 100 shown in Figs. 1 to 3 mainly in the diameter of the hole 116. Specifically, in the heating device 100 shown in Fig. 5, the hole 116 has a larger diameter than each of the plurality of recesses 113.

[0040] In this way, by making the diameter of hole 116 larger than the diameter of each of the multiple recesses 113, the surface area and cross-sectional area of ​​hole 116 are increased, promoting heat dissipation to the atmosphere within hole 116 and further improving the thermal uniformity around hole 116 on upper surface 110a.

[0041] Fig. 6 is a cross-sectional view of a heating device 100 according to a third modified example of the embodiment. The heating device 100 shown in Fig. 6 differs from the heating device 100 shown in Fig. 5 mainly in that the hole 116 penetrates the heating plate 110 to the lower surface 110b, which is the surface opposite the heating surface, and in that a cover member 180 is disposed in the hole 116. Specifically, in the heating device 100 shown in Fig. 6, the hole 116 penetrates the first plate member 111, the heat insulating member 115, and the second plate member 112 that constitute the heating plate 110 to the lower surface 110b.

[0042] The hole portion 116 includes a first through hole 116a penetrating the first plate member 111 and a second through hole 116b penetrating the second plate member 112. The first through hole 116a and the second through hole 116b have approximately the same diameter. An exposed surface 115b of the heat insulating member 115, which is exposed between the first through hole 116a and the second through hole 116b, is recessed outward from the inner circumferential surfaces of the first through hole 116a and the second through hole 116b, forming a step between the first through hole 116a and the second through hole 116b. An annular cover member 180 is disposed at the step between the first through hole 116a and the second through hole 116b. The cover member 180 covers the exposed surface 115b of the heat insulating member 115. The cover member 180 may be made of a material such as ceramic or metal that has high heat resistance.

[0043] That is, the heating plate 110 may have an annular cover member 180 in the hole 116. The cover member 180 may cover the exposed surface 115b of the heat insulating member 115. This can reduce deterioration of the heat insulating member 115.

[0044] In this way, by having the holes 116 penetrate the heating plate 110 to the lower surface 110b, the surface area and cross-sectional area of ​​the holes 116 are increased, which promotes heat dissipation to the atmosphere inside the holes 116 and further improves the thermal uniformity around the holes 116 on the upper surface 110a.

[0045] Furthermore, by covering exposed surface 115b of heat insulating member 115 that is exposed in hole 116 with cover member 180, it is possible to reduce the adhesion of dust in the atmosphere in hole 116 to heat insulating member 115. This reduces deterioration of heat insulating member 115.

[0046] FIG. 7 is a cross-sectional view of a heating device 100 according to a fourth modified example of the embodiment. The heating device 100 shown in FIG. 7 differs from the heating device 100 shown in FIG. 6 in the arrangement of the cover member 180. Specifically, in the heating device 100 shown in FIG. 7, the cover member 180 is fitted into a groove 111c formed in the lower surface 111a of the first plate member 111 with a gap between the cover member 180 and the inner surface of the groove 111c. The cover member 180 is not bonded to the inner surface of the groove 111c with a bonding material. In other words, lateral movement of the cover member 180 within the groove 111c is not restricted.

[0047] In this way, by fitting the cover member 180 into the groove portion 111c of the first plate member 111 with a gap therebetween, it is possible to prevent the cover member 180 from falling off while allowing the cover member 180 to move laterally.

[0048] That is, the cover member 180 may be fitted into the groove 111c formed on at least one of the surface of the first plate member 111 opposite to the first surface and the surface of the second plate member opposite to the second surface, with a gap provided between the cover member 180 and the inner surface of the groove 111c. This makes it possible to prevent the cover member 180 from falling off while allowing the cover member 180 to move laterally.

[0049] Furthermore, by not joining the cover member 180 to the inner side surface of the groove portion 111c, stress concentration on the cover member 180 due to thermal expansion and thermal contraction of the first plate member 111 can be alleviated.

[0050] The cover member 180 may be fitted into a groove formed in the upper surface 112a of the second plate member 112 with a gap between it and the inner surface of the groove. The cover member 180 may also be fitted into grooves formed in both the lower surface 111a of the first plate member 111 and the upper surface 112a of the second plate member 112 with a gap between it and the inner surface of the groove.

[0051] FIG. 8 is a top view of a heating device 100 according to a fifth modified example of the embodiment. The heating device 100 shown in FIG. 8 differs from the heating device 100 shown in FIGS. 1 to 3 in that other holes different from the hole 116 are formed in the upper surface 110a of the heating plate 110, which is the heating surface. Specifically, a plurality of other holes 117 (four in this example) extending in the thickness direction are formed in positions different from the hole 116 on the upper surface 110a of the heating plate 110 shown in FIG. 8. The positions where the plurality of other holes 117 are formed may be arbitrary. For example, the plurality of other holes 117 may be formed at equal intervals along the outer periphery of the hole 116 on the upper surface 110a.

[0052] In this way, by forming multiple other holes 117 at positions different from hole 116 on the upper surface 110a of the heating plate 110, distortion due to thermal expansion and thermal contraction of the heating plate 110 can be absorbed by the multiple other holes 117.

[0053] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0054] 100 Heating device 110 Heating Plate 110a top side 110b Bottom side 111 first plate member 111a Bottom side 111b recess 111c Groove 112 second plate member 112a Top side 112b Through hole 113 Recess 114 Joint members 115 Heat insulating materials 115a Through hole 115b Exposed surface 116 Hole 116a First through hole 116b Second through hole 117 Hole 120 Heater 120a tip 120b proximal end 121 Mounting material 121a Male thread 122, 123 Power supply terminal 130 Fixing Plate 130a fixing hole 131 Connecting member 140 Spacer member 170 Spacer member 180 Cover member

Claims

1. A heating plate; a plurality of heaters; the heating plate has a first surface and a second surface opposite the first surface; The first surface has a hole in the center thereof, the second surface has a plurality of recesses; the plurality of heaters are inserted into the plurality of recesses in the heating plate, respectively, and are positioned around the hole in a plan view; The heating plate is a first plate member having the first surface; a second plate member having the second surface; a heat insulating member located between the first plate member and the second plate member; and the hole penetrates the first plate member, the heat insulating member, and the second plate member; the heating plate has an annular cover member in the hole, The cover member covers the exposed surface of the heat insulating member.

2. The heating device according to claim 1 , wherein the hole has a diameter on the first surface side that is smaller than a diameter on the second surface side.

3. The heating device according to claim 1 or 2, wherein the hole has a diameter larger than that of each of the plurality of recesses.

4. 2. The heating device according to claim 1, wherein the cover member is fitted into a groove formed on at least one of a surface of the first plate member opposite the first surface and a surface of the second plate member opposite the second surface, with a gap between the cover member and an inner surface of the groove.

5. The heating device according to claim 4 , wherein the cover member is not bonded to the inner surface of the groove portion with a bonding material.

6. The heating device according to claim 1 , wherein the heating plate has a plurality of other holes at positions different from the positions of the holes on the first surface.

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