JP7756866B2 - Mold heating device and mold heating method - Google Patents

Description

The present invention relates to a mold heating device and mold heating method used when coating a mold with a mold wash, etc.

Regarding the application and firing of a heat-retaining mold wash to a mold for aluminum casting, Japanese Patent Application Laid-Open No. 2012-245561 (Patent Document 1), paragraph [0022] discloses that the base coat and main coat are preferably applied at a mold surface temperature of 200 to 250°C, and that the surface temperature can be adjusted by heating in an atmospheric furnace, directly with a burner, or by heating the mold using a heater attached to it. It also discloses that firing at 350 to 400°C after coating is more preferable.

Japanese Patent Application Laid-Open No. 2012-245561

Among the methods for heating molds when applying the above-mentioned mold wash, those using atmospheric furnaces require fuel, make it difficult to frequently switch operating states, and there is room for reducing energy consumption and carbon dioxide emissions.
On the other hand, when a burner is used, if the burner is large, it is the same as when an atmospheric furnace is used, but if the burner is small, it takes a long time to heat the mold and temperature unevenness may occur in the mold, which may affect the quality of the coating of the mold wash.
On the other hand, when a heater is set in a mold, it is difficult to set the heater in a state where temperature variations are suppressed for molds with complex shapes such as aluminum automobile engine molds.

The main object of the present invention is to provide a mold heating device and mold heating method that can heat molds with complex shapes for complex-shaped products while suppressing the occurrence of temperature unevenness.

The invention described in claim 1 is a mold heating device comprising a heater on which a heating object, which is part or all of a mold, is placed, and a case covering the heating object, wherein the heater is equipped with an infrared heater having a carbonaceous heating element that emits infrared rays when electricity is applied, the heating object is placed on the heater via a plate, the plate having a plate hole and an auxiliary hole, the plate hole being located below the bottom surface, which is the surface opposite to the cavity surface, which is the surface on the fitting side of the heating object, and the auxiliary hole does not overlap with the heating object, allowing heat by convection to flow into the case .
According to a second aspect of the present invention , in the above-mentioned invention, the plate is placed with a gap therebetween through which the infrared heater is exposed.
The invention described in claim 3 is characterized in that, in the above invention, the infrared heater includes a first infrared heater and a second infrared heater having a greater heat generation amount than the first infrared heater, and the first infrared heater and the second infrared heater are arranged side by side with the second infrared heater positioned at an edge.
A fourth aspect of the present invention is characterized in that, in the above-mentioned invention, the second infrared heaters are disposed on both sides of the first infrared heater.

The invention described in claim 5 is a mold heating method in which a heating object, which is part or all of a mold, is heated by an infrared heater having a carbonaceous heating element that radiates infrared rays when electricity is passed through it, and includes a step of setting the heating object in relation to the infrared heater via a plate so that the bottom surface, which is the surface opposite to the cavity surface, which is the surface on the fitting side of the heating object , is facing downward and toward the infrared heater, and then setting a case that covers the heating object and heating it, wherein the plate has a plate hole and an auxiliary hole, the plate hole is positioned below the bottom surface, the auxiliary hole does not overlap with the heating object, and allows heat by convection to flow into the case .
According to a sixth aspect of the present invention , in the above-mentioned invention, the plate is set in a state in which there is a gap through which the infrared heater is exposed.
The invention described in claim 7 is characterized in that, in the above invention, the infrared heater includes a first infrared heater and a second infrared heater having a greater heat generation amount than the first infrared heater, and the first infrared heater and the second infrared heater are arranged side by side with the second infrared heater positioned at an edge.
An eighth aspect of the present invention is characterized in that, in the above-mentioned invention, the second infrared heaters are disposed on both sides of the first infrared heater.

The main advantage of the present invention is that it provides a mold heating device and mold heating method that can heat molds with complex shapes while suppressing the occurrence of temperature unevenness.

1 is a perspective view of a mold heating device 1 according to the present invention. FIG. 2 is an exploded perspective view of the main part of FIG. 1 . 2A is a top view of the heater in FIG. 1, (B) a front view, (C) a cross-sectional view along line A-A, (D) a cross-sectional view along line B-B, and (E) a cross-sectional view along line C-C. 4A and 4B are a top view and a right side view, respectively, of the first infrared heater 21 in FIG. 3 . 1A is a top view, FIG. 1B is a rear view, and FIG. 1C is a right side view of a mold heating device for a first heating target. 1A is a top view, FIG. 1B is a rear view, and FIG. 1C is a right side view of a plate related to a first heating target. 10A is a top view, FIG. 10B is a rear view, and FIG. 10C is a right side view of a mold heating device for a second heating target. 10A is a top view, FIG. 10B is a rear view, and FIG. 10C is a right side view of a plate related to a second heating target. 10A, 10B, and 10C are top, rear, and right side views, respectively, of a mold heating device for a third heating target. 10A, 10B, and 10C are top, rear, and right side views, respectively, of a plate related to a third heating target. 10 is a flowchart showing an example of the operation of the mold heating device (an example of a mold heating method).

Hereinafter, examples of embodiments of the present invention will be described together with modifications thereof with reference to the accompanying drawings as appropriate.
The embodiment is not limited to the following examples and modifications.

Fig. 1 is a perspective view of a mold heating device 1 according to the present invention, and Fig. 2 is an exploded perspective view of the main part of Fig. 1.
The mold heating device 1 includes a heater 2, a carriage 4, a first table 6, a second table 7, a case 8, a plate 10, and a control unit 14.

The heater 2 is placed on a carriage 4 .
The cart 4 has a body 4B, multiple (four) casters 4C, and a handle 4H. The body 4B is a horizontal plate and carries the heater 2. The casters 4C are located on the underside of each of the four corners of the body 4B. The handle 4H is frame-shaped and located on the upper side of one side of the body 4B. The cart 4 is placed on the floor F. Regarding the orientation of the mold heating device 1, the side on which the heater 2 is located relative to the body 4B is the upper side. The side on which the handle 4H is located is the rear side. The right-hand side when the user faces forward is the right side. The orientation of the mold heating device 1 is determined for convenience of explanation and may change depending on the movement and installation of various components and parts. The cart 4 may be omitted or may not be included as a component of the mold heating device 1.

Fig. 3(A) is a top view of the heater 2. Fig. 3(B) is a front view of the heater 2. Fig. 3(C) is a cross-sectional view taken along line A-A in Fig. 3(A). Fig. 3(D) is a cross-sectional view taken along line B-B in Fig. 3(A). Fig. 3(E) is a cross-sectional view taken along line C-C in Fig. 3(A).
The heater 2 has a housing 20 , a plurality of (nine) first infrared heaters 21 , and a plurality of (six) second infrared heaters 22 .

The housing 20 includes a main housing 24 , a front housing 26 , and a rear housing 28 .
The main body housing 24 has a main body housing outer shell 24A, a plurality of heat insulating plates 24B, a plurality of (four) legs 24C, and a plurality of (two) leg plates 24D.
The main body housing outer shell 24A is made of metal and has a box shape that is open upward.
Each insulating plate 24B is a plate-shaped member made of insulating material. The insulating material is formed by laminating multiple layers containing a fibrous silica-based substance with aligned fiber directions, with the layers having different fiber directions. Each insulating plate 24B is white and reflects infrared rays. Each insulating plate 24B is arranged to cover the inner surface (five surfaces: top, bottom, left, right, and bottom) of the main housing outer casing 24A. Note that other insulating materials may also be used. Each insulating plate 24B may be a single-layer plate. Each insulating plate 24B does not have to be white. Each insulating plate 24B may have low infrared reflectivity.
The legs 24C protrude downward from the four corners of the bottom surface of the main body housing 24.
Each leg plate 24D extends in the front-to-rear and up-to-down directions. The leg plates 24D protrude downward from the left and right edges of the lower surface of the main housing 24. The protruding height of each leg plate 24D is the same as the protruding height of each leg 24C.
The front housing 26 is made of metal and has a box shape that is open to the rear. The front housing 26 is attached to the front side of the main housing 24. The front housing 26 has a plurality of slits 26A and a plurality (three locations) of connector mounting holes 26B.
The rear housing 28 is made of metal and has a box shape that is open to the front. The rear housing 28 is attached to the rear side of the main housing 24. The rear housing 28 has a plurality of slits 28A.

The first infrared heaters 21 extend in the front-rear direction and are arranged side by side in the left-right direction within the same imaginary plane.
Each second infrared heater 22 extends in the front-to-rear direction. A plurality (three) of the second infrared heaters 22 are arranged to the right of the rightmost first infrared heater 21, and a plurality (three) of the second infrared heaters 22 are arranged to the right of the leftmost first infrared heater 21. The second infrared heaters 22 and the first infrared heaters 21 are arranged side by side in the left-to-right direction, belonging to the same imaginary plane.
At least one of the first infrared heaters 21 and the second infrared heaters 22 may be arranged in the left-right direction so as not to belong to the same imaginary plane. At least one of the first infrared heaters 21 and the second infrared heaters 22 may extend in the left-right direction and be arranged in the front-to-back direction, for example. Furthermore, the number of at least one of the first infrared heaters 21 and the second infrared heaters 22 may be increased or decreased from the above number. All of the second infrared heaters 22 may be omitted. The arrangement of at least one of the first infrared heaters 21 and the second infrared heaters 22 may be changed from the arrangement in which the same number of second infrared heaters 22 are arranged on both the left and right sides of each first infrared heater 21.

Fig. 4A is a top view of the first infrared heater 21. Fig. 4B is a right side view of the first infrared heater 21.
Each first infrared heater 21 has an outer tube 30 made of quartz glass, a carbonaceous heating element 32, multiple (two) inner tubes 33 made of quartz glass, an insulator 34, multiple (four) internal conductors 36, an internal connection portion 37, and multiple (two) heater conductors 38.

The outer tube 30 has a tubular shape extending in the left-right direction, more specifically, a cylindrical shape. The front end of the outer tube 30 has a horizontal flat portion 30F.
An inert gas (for example, argon gas) is sealed inside the outer tube 30 .
The outer tube 30 transmits infrared rays.
At least one of the flat plate portion 30F in the outer tube 30 and the sealing of the inert gas may be omitted.

The carbonaceous heating element 32 is disposed inside the outer tube 30. The carbonaceous heating element 32 has a length that is shorter than the outer tube 30 by an amount corresponding to the space for internal wiring.
The carbonaceous heating element 32 is formed from a plurality of (two) carbonaceous plates 32P. The carbonaceous heating element 32 is in a horizontal position. However, the position of the carbonaceous heating element 32 may be other than horizontal. Furthermore, the number of carbonaceous plates 32P for each first infrared heater 21 may be one, or three or more.
Each carbonaceous plate 32P is disposed within an inner tube 33. The first infrared heater 21 has a double-tube structure consisting of the outer tube 30 and each inner tube 33. Each inner tube 33 prevents short circuits between adjacent carbonaceous plates 32P and individually protects each carbonaceous plate 32P. An inert gas (e.g., argon gas) is sealed within each inner tube 33. Note that an inert gas does not necessarily have to be sealed between the outer tube 30 and the inner tube 33. The sealing of an inert gas within the inner tube 33 may be omitted. The carbonaceous heating element 32 may be protected by a single-tube structure or a triple- or more-tube structure.
Each carbonaceous plate 32P has slits of the same length cut alternately at equal intervals from both the front and rear sides over the entire surface except for the left and right ends. Therefore, the center of each carbonaceous plate 32P, i.e., the center of the carbonaceous heating element 32, has a serpentine shape. Two carbonaceous plates 32P are arranged side by side. The serpentine shape is not shown in figures other than FIG. 4. The serpentine shape does not have to be located in the center of the carbonaceous heating element 32. The location of the serpentine shape may differ for each carbonaceous plate 32P. A single carbonaceous plate 32P may have multiple serpentine shapes.
The carbonaceous heating element 32 emits infrared rays when energized. The carbonaceous heating element 32 emits infrared rays and generates heat mainly in the meandering portion because the electrical resistance is higher in the meandering portion than in other portions.

The insulator 34 has a cylindrical shape and is heat-resistant and insulating.
The insulator 34 is provided on the outside of the flat portion 30F of the outer pipe 30.
The insulator 34 is an inner conductor support portion that supports two inner conductors 36. The insulator 34 is also a heater conductor support portion that supports two heater conductors 38.
The insulator 34 may be disposed at a location other than the outside of the flat plate portion 30F.

Each of the inner conductors 36 is electrically conductive. Each of the inner conductors 36 is disposed within the outer tube 30. The inner portion of each of the inner conductors 36 in the front-to-rear direction is disposed within the corresponding inner tube 33. Each of the inner tubes 33 is supported by the corresponding inner conductor 36.
The first internal conductor 36 is electrically connected to the front end of the right carbonaceous plate 32P of the carbonaceous heating element 32 within the front portion of the right inner tube 33. The second internal conductor 36 is electrically connected to the rear end of the right carbonaceous plate 32P of the carbonaceous heating element 32 within the rear portion of the right inner tube 33. The third internal conductor 36 is electrically connected to the rear end of the left carbonaceous plate 32P of the carbonaceous heating element 32 within the rear portion of the left inner tube 33. The second and third internal conductors 36 are connected by internal connectors 37 located outside each inner tube 33 and within the outer tube 30. The internal connectors 37 are supported by the outer tube 30 and directly or indirectly support at least one of the carbonaceous plates 32P, each internal conductor 36, and each inner tube 33. The fourth inner conductor 36 is electrically connected to the front end of the left carbonaceous plate 32 P of the carbonaceous heating element 32 within the front part of the left inner tube 33 .
The first and second inner conductors 36 correspond to the right inner tube 33. The third and fourth inner conductors 36 correspond to the left inner tube 33.
The front end of the first internal conductor 36 and the front end of the fourth internal conductor 36 are disposed within the flat plate portion 30F. The two carbonaceous plates 32P are connected in series by the internal conductors 36 and the internal connection portion 37.

Each heater conductor 38 has a covering portion and a conductor portion disposed therein. Each conductor portion has electrical conductivity.
A conductor portion of the first heater conductor 38 is electrically connected to the first internal conductor 36. The first heater conductor 38 passes through the insulator 34 (flat portion 30F) from the connection portion with the first internal conductor 36 and extends forward.
A conductor portion of the second heater conductor 38 is electrically connected to the fourth internal conductor 36. The second heater conductor 38 passes through the insulator 34 (flat portion 30F) from the connection portion with the fourth internal conductor 36 and extends forward.
The heater conductors 38 may be arranged in a manner other than that described above. For example, the connection between the heater conductors 38 and the internal conductors 36 may be arranged outside the flat portion 30F. The heater conductors 38 may also be arranged vertically.

When power is supplied to the carbonaceous heating element 32 of each first infrared heater 21 through the heater conductors 38 and the internal conductors 36, the carbonaceous heating element 32 lights up, radiates infrared rays, and generates heat at a rate corresponding to the amount of power.
The outer tube 30, the inner tube 33, the insulators 34, the internal conductors 36, and the heater conductors 38 are non-heat-generating parts. That is, other than the carbonaceous heating element 32, which actively generates heat by electric power, the parts that receive heat from the carbonaceous heating element 32 and indirectly generate heat are not heat-generating parts.

The configuration of each second infrared heater 22 differs from the configuration of each first infrared heater 21 only in the configuration of the carbonaceous heating element 32 for increasing the maximum allowable heat generation amount.
In the carbonaceous heating element 32 of each second infrared heater 22, the distance between adjacent slits is wider than the distance between adjacent slits in the carbonaceous heating element 32 of each first infrared heater 21. Furthermore, the thickness (size in the vertical direction) of the carbonaceous heating element 32 of each second infrared heater 22 is thicker than the thickness of the carbonaceous heating element 32 of each first infrared heater 21. As a result, the maximum allowable power that can be applied to each second infrared heater 22 (e.g., 3.0 kW per heater) is greater than the maximum allowable power that can be applied to each first infrared heater 21 (e.g., 1.6 kW per heater), and the maximum allowable heat value of each second infrared heater 22 is greater than the maximum allowable heat value of each first infrared heater 21.

Each of the first infrared heaters 21 and each of the second infrared heaters 22 is held in a main body housing 24. The front and rear surfaces of the main body housing 24 have holes through which each of the first infrared heaters 21 and each of the second infrared heaters 22 passes.
The serpentine-shaped portions of the first infrared heaters 21 and the second infrared heaters 22 are disposed within the main housing 24 and are exposed upward. Infrared rays generated at the upper portions of the serpentine-shaped portions of the first infrared heaters 21 and the second infrared heaters 22 travel upward. On the other hand, infrared rays generated at the upper portions of the serpentine-shaped portions of the first infrared heaters 21 and the second infrared heaters 22 are reflected by the heat insulating plate 24B on the bottom surface of the main housing 24 and travel upward.
The front end of each first infrared heater 21 and the front end of each second infrared heater 22 are disposed within the front housing 26. A connector (not shown) is attached to each connector mounting hole 26B of the front housing 26. A plurality of (three) terminal blocks 40 are also provided within the front housing 26. Each heater lead wire 38 of each first infrared heater 21 and each heater lead wire 38 of each second infrared heater 22 are connected to the control unit 14 via the corresponding terminal block 40 and corresponding connector in the front housing 26. Each first infrared heater 21 is delta-connected in groups of three, and each second infrared heater 22 is delta-connected in groups of three. However, other connection methods may also be employed.
The rear end of each of the first infrared heaters 21 and the rear end of each of the second infrared heaters 22 are disposed within the rear housing 28 .

The first platform 6 is located to the right of the cart 4 and the heater 2 on it. The vertical position of the top surface of the first platform 6 is adjacent to or coincides with the vertical position of the top surface of the heater 2. The first platform 6 is heat resistant. Note that the first platform 6 may be omitted.

The second platform 7 is located to the left of the platform 4 and the heater 2 on it. The vertical position of the top surface of the second platform 7 is adjacent to or coincides with the vertical position of the top surface of the heater 2. The second platform 7 is heat resistant. Note that the second platform 7 may be omitted.

The case 8 is box-shaped and open downward. The case 8 has a jacket structure in which a hollow outer shell including multiple metal plates is filled with an insulating material. The insulating material is made of alkaline earth silicate (AES) wool, which is needle-punched while laminating fibers in layers during the manufacturing process, and the fibers are entangled to form a blanket-like shape. However, other insulating materials may also be used. The insulating material may be in the form of a block and fitted into the outer shell. The insulating material may also be attached to the inner surface of the outer shell. The insulating material may be the same as that of the insulating plate 24B.
The case 8 has a right-end case portion 8R, a first intermediate case portion 8C, a second intermediate case portion 8D, and a left-end case portion 8L. Two handles 42 are provided on the top surfaces of each of these portions. Each handle 42 has a portion extending laterally at a distance from the top surface of the case 8 and a portion extending vertically connecting the lower portions on both the left and right sides to the top surface of the case 8. The handles 42 make it easy to hang the right-end case portion 8R, the first intermediate case portion 8C, the second intermediate case portion 8D, and the left-end case portion 8L from a crane (not shown), facilitating movement and installation.
The right-end case portion 8R is box-shaped and open to the left and downward. The first intermediate case portion 8C and the second intermediate case portion 8D are box-shaped and open to the left, right, and downward. The left-end case portion 8L is box-shaped and open to the right and downward. Because the case 8 includes multiple case portions that can be separated from each other, it is easy to install the case 8 so as to cover the heating target W while minimizing contact with the heating target W, even if the heating target W is placed above the heater 2.
The case 8 is placed on the heater 2, the first base 6, and the second base 7. More specifically, the right-end case portion 8R is placed on the first base 6. The first intermediate case portion 8C and the second intermediate case portion 8D are placed on (the front and rear walls of) the main body housing 24 of the heater 2. The left-end case portion 8L is placed on the second base 7.

Fig. 5(A) is a top view of the mold heating device 1 for the first heating target WA. Fig. 5(B) is a rear view of the mold heating device 1 for the first heating target WA. Fig. 5(C) is a right side view of the mold heating device 1 for the first heating target WA. Fig. 6(A) is a top view of the plate 10A for the first heating target WA. Fig. 6(B) is a rear view of the plate 10A for the first heating target WA. Fig. 6(C) is a right side view of the plate 10A for the first heating target WA.
Fig. 7(A) is a top view of the mold heating device 1 for the second heating target WB. Fig. 7(B) is a rear view of the mold heating device 1 for the second heating target WB. Fig. 7(C) is a right side view of the mold heating device 1 for the second heating target WB. Fig. 8(A) is a top view of the plate 10B for the second heating target WB. Fig. 8(B) is a rear view of the plate 10B for the second heating target WB. Fig. 8(C) is a right side view of the plate 10B for the second heating target WB.
Figure 9(A) is a top view of the mold heating device 1 for the third heating target WC. Figure 9(B) is a rear view of the mold heating device 1 for the third heating target WC. Figure 9(C) is a right side view of the mold heating device 1 for the third heating target WC. Figure 10(A) is a top view of the plate 10C for the third heating target WC. Figure 10(B) is a rear view of the plate 10C for the third heating target WC. Figure 10(C) is a right side view of the plate 10C for the third heating target WC.
The shape of the plate 10 is based on the shape (type) of the heating target W. The heating target W includes three types: a first heating target WA, a second heating target WB, and a third heating target WC. The plate 10 includes a first plate 10A, a second plate 10B, and a third plate 10C according to the types of heating target W. Hereinafter, the first heating target WA, the second heating target WB, and the third heating target WC may be collectively or representatively referred to as heating target W, and similarly, the first plate 10A, the second plate 10B, and the third plate 10C may be collectively or representatively referred to as plate 10.
The heating object W is a metal mold (casting die) made of aluminum (including alloys) for a cylinder head of an automobile engine.
The plate 10 is disposed on the upper side of the heater 2 (main body housing 24). The plate 10 is placed on the first base 6 and the second base 7. The plate 10 is made of metal.

There are two first heating targets WA, a left mold WAL and a right mold WAR. The cavity surface (the surface on the mold fitting portion side) of the left mold WAL is larger than the cavity surface of the right mold WAR.
The first plate 10A has a base portion 10AB, a front wall portion 10AF, a rear wall portion 10AR, a first plate hole 10AX, a second plate hole 10AY, a first wall portion 10A1, a second wall portion 10A2, a third wall portion 10A3, a fourth wall portion 10A4, a first plate auxiliary hole 10AJ, and a second plate auxiliary hole 10AK.
The base portion 10AB is horizontal and plate-shaped.
The front wall 10AF protrudes upward from the front edge of the upper surface of the base 10AB and extends in the left-right direction. The rear wall 10AR protrudes upward from the rear edge of the upper surface of the base 10AB and extends in the left-right direction.
The first plate hole 10AX is provided on the left side of the base portion 10AB. The second plate hole 10AY is provided on the right side of the base portion 10AB. The first plate hole 10AX is larger than the second plate hole 10AY.
The first wall portion 10A1 protrudes upward from the top surface of the base portion 10AB to the left of the first plate hole 10AX. The first wall portion 10A1 extends in the front-to-rear direction. The front-to-rear length of the first wall portion 10A1 is the same as the front-to-rear length of the first plate hole 10AX, more specifically, the former length is slightly longer than the latter length. The second wall portion 10A2 protrudes upward from the top surface of the base portion 10AB in front of the first plate hole 10AX. The second wall portion 10A2 extends in the left-to-right direction. The left-to-right length of the second wall portion 10A2 is the same as the left-to-right length of the first plate hole 10AX, more specifically, the former length is slightly shorter than the latter length.
The third wall portion 10A3 protrudes upward from the top surface of the base portion 10AB to the right of the second plate hole 10AY. The third wall portion 10A3 extends in the front-to-rear direction. The front-to-rear length of the third wall portion 10A3 is the same as the front-to-rear length of the second plate hole 10AY, more specifically, the former length is slightly longer than the latter length. The fourth wall portion 10A4 protrudes upward from the top surface of the base portion 10AB in front of the second plate hole 10AY. The fourth wall portion 10A4 extends in the left-to-right direction. The left-to-right length of the fourth wall portion 10A4 is the same as the left-to-right length of the second plate hole 10AY, more specifically, the former length is slightly longer than the latter length.
The first plate auxiliary hole 10AJ is provided on the left side of the base portion 10AB, on the left side of the first wall portion 10A1. The second plate auxiliary hole 10AK is provided on the right side of the base portion 10AB, on the right side of the second wall portion 10A2. At least one of the first plate auxiliary hole 10AJ and the second plate auxiliary hole 10AK may be omitted. Furthermore, at least one of the arrangement, shape, and size of the first plate auxiliary hole 10AJ and the arrangement, shape, and size of the second plate auxiliary hole 10AK may be changed from those described above.

Of the first heating target WA, the left mold WAL is placed on the first plate hole 10AX with the cavity surface facing up, i.e., with the bottom surface WALF of the left mold WAL (the surface opposite the main portion of the cavity surface) facing down. When viewed from above, the bottom surface WALF of the left mold WAL (excluding the peripheral edge) is within the first plate hole 10AX. One surface of the left mold WAL, including its long side, is in contact with the first wall portion 10A1, and one surface of the left mold WAL, including its short side, is in contact with the second wall portion 10A2. At least one of the first wall portion 10A1 and the second wall portion 10A2 allows for more accurate positioning of the left mold WAL relative to the first plate hole 10AX.
Of the first heating target WA, the right mold WAR is placed on the second plate hole 10AY with the cavity surface facing up, i.e., with the bottom surface WARF of the right mold WAR facing down. When viewed from above, the bottom surface WARF of the right mold WAR (excluding the peripheral edge) is within the second plate hole 10AY. One surface of the right mold WAR, including its long side, is in contact with the third wall portion 10A3, and one surface of the right mold WAR, including its short side, is in contact with the fourth wall portion 10A4. At least one of the third wall portion 10A3 and the fourth wall portion 10A4 allows for more accurate positioning of the right mold WAR relative to the second plate hole 10AY.
The first plate auxiliary hole 10AJ and the second plate auxiliary hole 10AK do not overlap the first heating target WA and are located above the second infrared heater 22. The first plate auxiliary hole 10AJ and the second plate auxiliary hole 10AK are holes for passing heat.

The second heating target WB is the lower mold, whose cavity surface is larger than the cavity surfaces of the left mold WAL and the right mold WAR.
The second plate 10B has a base portion 10BB, a front wall portion 10BF, a rear wall portion 10BR, a plate hole 10BX, a wall portion 10B1, a first plate auxiliary hole 10BJ, a second plate auxiliary hole 10BK, a third plate auxiliary hole 10BL, and a fourth plate auxiliary hole 10BM.
The base portion 10BB is horizontal and plate-shaped.
The front wall 10BF protrudes upward from the front edge of the upper surface of the base 10BB and extends in the left-right direction. The rear wall 10BR protrudes upward from the rear edge of the upper surface of the base 10BB and extends in the left-right direction.
The plate hole 10BX is provided in the center of the base portion 10BB and is larger than the first plate hole 10AX and the second plate hole 10AY in the first plate 10A.
The wall portion 10B1 protrudes upward from the upper surface of the base portion 10BB to the right of the plate hole 10BX. The wall portion 10B1 extends in the front-to-rear direction. The length of the wall portion 10B1 in the front-to-rear direction is the same as the length of the plate hole 10BX in the front-to-rear direction, and more specifically, the length of the wall portion 10B1 is equal to the length of the plate hole 10BX in the front-to-rear direction.
The first plate auxiliary hole 10BJ is provided in the left front portion of the base portion 10BB. The second plate auxiliary hole 10BK is provided in the right front portion of the base portion 10BB. The third plate auxiliary hole 10BL is provided in the left rear portion of the base portion 10BB. The fourth plate auxiliary hole 10BM is provided in the right rear portion of the base portion 10BB. At least one of the first to fourth plate auxiliary holes 10BJ to 10BM may be omitted. Also, at least one of the arrangement, shape, and size of the first to fourth plate auxiliary holes 10BJ to 10BM may be changed from those described above.

The second heating target WB is placed on the plate hole 10BX with the cavity surface facing up, i.e., with the bottom surface WBF facing down. When viewed from above, the bottom surface WBF of the second heating target WB (excluding the peripheral edge) is within the plate hole 10BX. One surface of the second heating target WB, including its short side, is in contact with the wall portion 10B1. The wall portion 10B1 allows for more accurate positioning of the second heating target WB relative to the plate hole 10BX.
The first to fourth plate auxiliary holes 10BJ to 10BM do not overlap the second heating target WB and are located above the second infrared heater 22. The first plate auxiliary hole 10BJ, the second plate auxiliary hole 10BK, the third plate auxiliary hole 10BL, and the fourth plate auxiliary hole 10BM are holes for passing heat.

The third heating object WC includes a plurality (four) of pin WCPs as cores corresponding to a plurality (four) of cylinders. All of the pin WCPs are placed upright in a single row in one stand WCS. The underside of the stand WCS has a plurality (four) of holes of the same size as the bottom surfaces WCPF of the pin WCPs, and the bottom surfaces WCPF of each pin WCP are exposed downward through the holes. The stand WCS is for heating purposes and is not included in the mold.
The third plate 10C has a base portion 10CB, a front wall portion 10CF, a rear wall portion 10CR, a first plate hole 10CW, a second plate hole 10CX, a third plate hole 10CY, a fourth plate hole 10CZ, and a wall portion 10C1.
The base portion 10CB is horizontal and plate-shaped.
The front wall 10CF protrudes upward from the front edge of the upper surface of the base 10CB and extends in the left-right direction. The rear wall 10CR protrudes upward from the rear edge of the upper surface of the base 10CB and extends in the left-right direction.
The first plate hole 10CW to the fourth plate hole 10CZ are provided in a line in the left-right direction in the center of the base portion 10CB.
The wall portion 10C1 protrudes upward from the top surface of the base portion 10CB to the left of the leftmost first plate hole 10CW. The wall portion 10C1 extends in the front-to-rear direction. The length of the wall portion 10C1 in the front-to-rear direction is the same as the length of the stand WCS in the front-to-rear direction. More specifically, the length of the wall portion 10C1 is equal to the length of the stand WCS in the front-to-rear direction.
The front-to-rear dimension of the third plate 10C is shorter than the front-to-rear dimensions of the first plate 10A and the second plate 10B. A first gap GA1 exists in front of the third plate 10C disposed above the heater 2, through which the first infrared heater 21 and the second infrared heater 22 are exposed (inside the case 8) without being blocked by the third plate 10C. A second gap GA2 exists behind the third plate 10C disposed above the heater 2, through which the first infrared heater 21 and the second infrared heater 22 are exposed (inside the case 8). At least one of the first gap GA1 and the second gap GA2 may be omitted. The arrangement, shape, and size of the first gap GA1 and/or the arrangement, shape, and size of the second gap GA2 may be changed from those described above. Furthermore, one or more plate auxiliary holes may be provided in the third plate 10C.

The third heating target WC is placed on the first plate hole 10CW to the fourth plate hole 10CZ with the cavity surface facing up, i.e., with the bottom surface WCPF facing down. When viewed from above, the bottom surface WCPF of each pin WCP (excluding its peripheral edge) is located inside the corresponding first plate hole 10CW to the fourth plate hole 10CZ. A portion of the stand WCS is in contact with the wall portion 10C1. The wall portion 10C1 allows for more accurate positioning of the third heating target WC relative to the first plate hole 10CW to the fourth plate hole 10CZ.
The first gap GA1 and the second gap GA2 do not overlap with the third heating target WC.

Hereinafter, the various bottom surfaces WALF, WARF, WBF, and WCPF may be collectively referred to as bottom surface WF.
Furthermore, the various plate holes 10AX, 10AY, 10BX, 10CW, 10CX, 10CY, and 10CZ may be collectively referred to as plate hole 10X.
Furthermore, the various plate auxiliary holes 10AJ, 10AK, 10BJ, 10BK, 10BL, and 10BM may be collectively referred to as plate auxiliary holes 10K.

The control unit 14 is provided outside the heater 2. The control unit 14 may be provided integrally with the heater 2. The control unit 14 does not have to be included in the components of the mold heating device 1.
The control unit 14 controls the supply of power to each of the first infrared heaters 21 and each of the second infrared heaters 22. The power is supplied from a power source (not shown).

An example of the operation of such a mold heating device 1 (an example of a mold heating method) will be described below.
FIG. 11 is a flowchart relating to this operation example.
The user uses the mold heating device 1 to raise the temperature of the heating target W for preheating the mold coating and baking the mold wash. Note that preheating may be omitted. The mold heating device 1 may also be used for other mold heating, such as preheating for product molding after baking.
The heating state of the object W to be heated during preheating before baking the mold wash depends strictly on the type of mold wash, etc., but in this case, taking into account general mold washes, it is assumed that the object W to be heated is heated uniformly without temperature unevenness to a degree that the temperature is within ±40°C in any part of the main temperature range of 200°C or more and 250°C or less.
As a state prior to preheating (initial state), the case 8 is removed from above the heater 2, and the control unit 14 turns off each of the first infrared heaters 21 and each of the second infrared heaters 22 (step S1).

The user places the plate 10 corresponding to the desired heating object W on the heater 2 (step S2), and sets the heating object W on the plate 10 with the bottom surface WF facing the heater 2 (bottom side) (step S3).
Next, the user determines whether or not to install a case 8 for preheating depending on the heating object W (step S4). Here, the first heating object WA (left mold WAL and right mold WAR) and the third heating object WC (pin WCP, etc.) can reach the desired heating state without installing a case 8 covering the heating object W, so installation of a case 8 covering the heating object W is unnecessary. On the other hand, the second heating object WB (lower mold) can more easily reach the desired heating state by installing a case 8 covering the heating object W, so a case 8 covering the heating object W is installed.

Next, the user turns on each of the first infrared heaters 21 and each of the second infrared heaters 22 using the control unit 14 to start heating the heating target W (step S5). Each of the first infrared heaters 21 and each of the second infrared heaters 22 is turned on at the maximum allowable power. The user turns on each of the first infrared heaters 21 and each of the second infrared heaters 22 for a predetermined time. The power (heat generation amount) of at least one of the first infrared heaters 21 and each of the second infrared heaters 22 may be adjusted by operating the control unit 14 or based on temperature information obtained from a temperature sensor attached to at least one of the heater 2, the first base 6, the second base 7, the case 8, the plate 10, and the heating target W. The turn-on time of each of the first infrared heaters 21 and each of the second infrared heaters 22 may also be adjusted based on temperature information obtained from the temperature sensor; for example, the turn-on time may be adjusted until temperature information indicating a predetermined temperature or higher continues for a specific time.
According to tests using a temperature sensor, the temperature rise of the heated object W is roughly proportional to the heating time (the time elapsed from the start of lighting of each first infrared heater 21 and each second infrared heater 22), and when a case 8 covering the heated object W is installed, the heated object W reaches 200°C from room temperature in about 10 to 20 minutes.
The heating object W is heated with the bottom surface WF of the heating object W facing the heater 2, so the cavity surface side (the mating portion side) is also heated by heat conduction from the bottom surface WF, and the heating object W is heated with temperature unevenness suppressed. In particular, even if the heating object W has complex irregularities such as components of a mold for a cylinder head, temperature unevenness is suppressed by heating the bottom surface WF facing the heater 2.
Furthermore, in each of the first infrared heaters 21 and each of the second infrared heaters 22, the second infrared heaters 22, which have higher output than the first infrared heaters 21, are arranged at the peripheral portions, so that each second infrared heater 22, which generates more heat, can be used at the peripheral portions where heat is more likely to escape than at the center, resulting in better thermal efficiency and suppressing the occurrence of temperature unevenness in the heated object W.
Furthermore, the object to be heated W is placed on the heater 2 via a plate 10 having a plate hole 10X shaped according to the bottom surface WF, which is the surface opposite the cavity surface, so that the radiant heat of each first infrared heater 21 and each second infrared heater 22 can act directly on the bottom surface WF, making it possible to heat the object to be heated with temperature unevenness being further suppressed.
Furthermore, since the plate 10 is placed on the heater 2 via the plate 10 having plate auxiliary holes 10K that allow heat to pass through without being blocked by the heating target W, the heat from each of the first infrared heaters 21 and each of the second infrared heaters 22 is taken in more quickly through the plate auxiliary holes 10K, and more heat flows in from below due to convection and infrared radiation, making it possible to heat the heating target W with further suppressed temperature unevenness and in a shorter heating time. Such an action is also achieved by the first gap GA1 and second gap GA2 associated with the third plate 10C.

After a predetermined time has elapsed, the first infrared heaters 21 and the second infrared heaters 22 are turned off and extinguished, completing the preheating (step S6).
The turning off may be performed by a user's operation on the control unit 14, or by the control unit 14 detecting the passage of a predetermined time using a timer or a temperature sensor or the like.
The first infrared heaters 21 and the second infrared heaters 22 can be quickly turned off and on again due to the use of the carbonaceous heating elements 32, etc.
Furthermore, since the first infrared heaters 21 and the second infrared heaters 22 can be quickly turned back on, the first infrared heaters 21 and the second infrared heaters 22 can be frequently turned off (batch type), making the mold heating device 1 safer and more economical.
In addition, the mold heating device 1 can be turned off frequently, and the amount of heat that escapes to the surroundings is less than that of an atmospheric furnace (gas burner), so the temperature of the surrounding environment is less likely to rise. Therefore, the user can work in a cooler environment than in an atmospheric furnace.

When the case 8 is set, the user removes it with a crane. Then, the user transports the preheated heating object W to the painting booth and applies the mold wash to the cavity surface and other necessary areas (step S7). Note that application may also include spraying.

Then, the user places the heating object W with the mold wash on the heater 2 with the bottom surface WF facing downwards via a suitable plate 10 (step S8) to bake the mold wash (step S9).
The heating state of the object W to be heated when baking the mold wash depends strictly on the type of mold wash, etc., but here, taking into consideration general mold washes, it is assumed that the object W to be heated is heated uniformly without temperature unevenness to the extent that the temperature is within ±40°C in any part of the main temperature in the temperature range of 300°C or more and 400°C or less.
Since the heating temperature is high when baking the mold wash, the user installs cases 8 for covering the heating objects W for all the heating objects W (step S10). Note that the cases 8 for covering the heating objects W do not necessarily have to be installed when baking the mold wash.

Then, the user starts baking the mold wash by turning on each of the first infrared heaters 21 and each of the second infrared heaters 22 using the control unit 14, in the same manner as preheating except for the heating temperature (step S11), and after a predetermined time has passed, turns off each of the first infrared heaters 21 and each of the second infrared heaters 22 to complete the baking (step S12).

The user removes the case 8 and carries the heated object W with the baked mold wash to the molding booth for the product (cylinder head), and once all the mold parts are ready, the product is manufactured using the mold (step S13).
By performing at least one of preheating and baking of the mold wash in a state in which temperature unevenness is suppressed, the quality of the baked mold wash (mold coating) is improved, and the life of the coating (hardened paint film) is extended to about 1,200 shots compared to about 700 shots in the case of baking with a gas burner. In baking with a gas burner, the heating object W is heated by convection of heated air, which makes temperature unevenness likely to occur, but in the heater 2 using each of the first infrared heaters 21 and each of the second infrared heaters 22, the heating object W is heated by radiation, making temperature unevenness less likely to occur.

Such a mold heating device 1 has the following effects.
That is, the mold heating device 1 includes a heater 2 on which a heating target W, which is part or all of a mold, is placed, and a case 8 that covers the heating target W. The heater 2 includes infrared heaters (first infrared heaters 21 and second infrared heaters 22) having carbonaceous heating elements 32 that emit infrared rays when energized. Therefore, when the first infrared heaters 21 and second infrared heaters 22 are used for heating, the case 8 can separate the heating space in which the heating target W is set from the external space, providing a mold heating device 1 that can heat even molds with complex shapes while suppressing temperature unevenness. Furthermore, heating by the first infrared heaters 21 and second infrared heaters 22 suppresses an increase in ambient temperature and enables batch heating using electricity, improving energy savings.
The heating object W is placed on the heater 2 via a plate 10 having plate holes 10X shaped according to the bottom surface WF, which is the surface opposite the cavity surface. This allows the radiant heat of each of the first infrared heaters 21 and each of the second infrared heaters 22 to act directly on the bottom surface WF, making it possible to heat the heating object W with temperature unevenness further suppressed.
Furthermore, plates 10A and 10B have plate auxiliary holes 10K for passing heat. Also, plate 10C is placed with gaps GA1 and GA2 through which the infrared heater is exposed. Therefore, heat from the infrared heater flows in through plate auxiliary holes 10K and gaps GA1 and GA2, and the heating target W is heated with temperature unevenness further suppressed.
Furthermore, the infrared heater includes a first infrared heater 21 and a second infrared heater 22 that generates more heat than the first infrared heater 21, and the first infrared heater 21 and the second infrared heater 22 are arranged side by side with the second infrared heater 22 disposed on an edge. The second infrared heaters 22 are also disposed on both sides of the first infrared heater 21. As a result, the edge surrounding the heating object W is heated more intensely, heat release into the external space is suppressed, and the heating object W can be heated in a state where temperature unevenness is further suppressed and in a state where energy is more efficiently saved.

On the other hand, the mold heating method performed by the operation of the mold heating device 1 is a method in which the heating target W, which is part or all of the mold, is heated by infrared heaters (each of the first infrared heaters 21 and each of the second infrared heaters 22), and the heating target W is heated by setting it so that the bottom surface WF, which is the surface of the heating target W opposite the cavity surface, faces the infrared heater (steps S3, S9). Therefore, the bottom surface WF, which has a simpler shape than the cavity surface of the mold, is heated directly, and the part on the cavity surface side is heated mainly by heat transfer from the bottom surface WF, so the heating target W is heated in a state in which the occurrence of temperature unevenness is further suppressed.
The heating target W is placed above the first infrared heaters 21 and the second infrared heaters 22, with the bottom surface WF facing downward (steps S3 and S9). Thus, the user can more easily achieve direct heating of the bottom surface BF and indirect heating of the cavity surface by simply placing a heavy metal mold with the bottom surface BF facing downward on the first infrared heaters 21 and the second infrared heaters 22.
Furthermore, the heating target W is set relative to each of the first infrared heaters 21 and each of the second infrared heaters 22 via the plate 10 having plate holes 10X shaped according to the bottom surface WF (steps S2 and S8). Thus, the radiant heat of each of the first infrared heaters 21 and each of the second infrared heaters 22 acts directly on the bottom surface WF through the plate holes 10X, and the heating target W is heated in a state where the occurrence of temperature unevenness is further suppressed.
Furthermore, plates 10A and 10B have plate auxiliary holes 10K for passing heat. Plate 10C is set with gaps GA1 and GA2 through which the infrared heater is exposed. Therefore, heat from the infrared heater flows in through plate auxiliary holes 10K and gaps GA1 and GA2, and the heating target W is heated with temperature unevenness further suppressed.
In addition, after the heating target W is set, a case 8 that covers the heating target W is set (steps S4 and S10), and the heating target W is heated. Therefore, the heating space in which the heating target W is set can be separated from the external space, and heating can be performed with temperature unevenness further suppressed, even for molds with complex shapes.
Furthermore, each of the first infrared heaters 21 and each of the second infrared heaters 22 has a carbonaceous heating element 32 that emits infrared rays when powered on. Therefore, each of the first infrared heaters 21 and each of the second infrared heaters 22 that emit infrared rays with a higher output can be more easily formed.
Furthermore, the infrared heater includes a first infrared heater 21 and a second infrared heater 22 that generates more heat than the first infrared heater 21, and the first infrared heater 21 and the second infrared heater 22 are arranged side by side with the second infrared heater 22 disposed on an edge. The second infrared heaters 22 are also disposed on both sides of the first infrared heater 21. As a result, the edge surrounding the heating object W is heated more intensely, heat release into the external space is suppressed, and the heating object W can be heated in a state where temperature unevenness is further suppressed and in a state where energy is more efficiently saved.

The above-described embodiments and modifications of the present invention further include the following modifications as appropriate.
The materials of various members or parts may be changed, such as the main body housing outer shell 24A being made of heat-resistant plastic.
The number, arrangement, configuration, etc. of various members or parts may be changed, such as providing a third base in addition to the first base 9 and the second base 7, making the case 8 an integrated type, making the plate 10 a separable type in which each part can be separated, making the plate 10 foldable, etc. Changing the number of various members or parts may include reducing the number to zero, i.e., omitting various members or parts.
The carbonaceous heating element 32 of at least one of the first infrared heaters 21 and the second infrared heaters 22 may have a first heating portion and a second heating portion that generates a larger amount of heat than the first heating portion. The difference between the heat generation amounts of the first heating portion and the second heating portion can be set, for example, by varying the width of a slit provided in the carbonaceous heating element 32. The carbonaceous heating element 32 of each first infrared heater 21 sandwiched between the left and right second infrared heaters 22 may have second heating portions on both the upper and lower sides of the first heating portion, and the center of each first infrared heater 21 may be surrounded by the second heating portion that generates a larger amount of heat and each second infrared heater 22. The maximum allowable heat generation amount of the second heating portion and the maximum allowable heat generation amount of each second infrared heater 22 may be the same.

1: Mold heating device, 2: Heater, 8: Case, 10: Plate, 10K: Plate auxiliary hole (auxiliary hole), 10X: Plate hole (hole), 21: First infrared heater (infrared heater), 22: Second infrared heater (infrared heater), 32: Carbonaceous heating element, GA1, GA2: Gap, W: Heated object (part or all of the mold), WF: Bottom surface (of the mold).

Claims (8)

A heater on which a heating target, which is a part or all of the mold, is placed;
a case that covers the object to be heated;
It is equipped with
the heater includes an infrared heater having a carbonaceous heating element that emits infrared rays when energized ,
The heating target is placed on the heater via a plate,
The plate has a plate hole and an auxiliary hole,
the plate hole is disposed below a bottom surface, which is a surface opposite to a cavity surface, which is a surface on the fitting portion side of the heating target;
The auxiliary holes do not overlap with the heating object, and allow heat generated by convection to flow into the case.
A mold heating device characterized by: 2. The mold heating method according to claim 1 , wherein the plate is placed with a gap therebetween through which the infrared heater is exposed. the infrared heater includes a first infrared heater and a second infrared heater that generates a larger amount of heat than the first infrared heater,
3. The mold heating device according to claim 1, wherein the first infrared heater and the second infrared heater are arranged side by side with the second infrared heater disposed at an edge. The mold heating device according to claim 3 , wherein the second infrared heaters are disposed on both sides of the first infrared heater. A mold heating method in which a heating target, which is a part or all of a mold, is heated by an infrared heater having a carbonaceous heating element that radiates infrared rays when energized ,
the step of setting the heating object on the infrared heater via a plate so that the bottom surface, which is the surface opposite to the cavity surface, which is the surface on the fitting portion side of the heating object , faces downward and is on the infrared heater side , and then setting a case that covers the heating object and heating the heating object,
The plate has a plate hole and an auxiliary hole,
the plate hole is disposed below the bottom surface;
The auxiliary holes do not overlap with the heating object, and allow heat generated by convection to flow into the case.
A mold heating method characterized by: 6. The mold heating method according to claim 5 , wherein the plate is set with a gap through which the infrared heater is exposed. the infrared heater includes a first infrared heater and a second infrared heater that generates a larger amount of heat than the first infrared heater,
7. The mold heating method according to claim 5, wherein the first infrared heater and the second infrared heater are arranged side by side with the second infrared heater disposed on an edge. The mold heating method according to claim 7 , wherein the second infrared heaters are disposed on both sides of the first infrared heater.