JP2024144004A - Heater device and hot runner device equipped with same - Google Patents

Abstract

To provide a heater device capable of reducing a power use amount.SOLUTION: A heater device 1 comprises: a band heater 10; and a jacket 20. The jacket 20 is provided to an outer periphery of a column-like part of an ejection nozzle 60 to cover the outer periphery. The band heater 10 is thermally coupled to the jacket 20, and indirectly heats the column-like part via the jacket 20. The jacket 20 is made of aluminum, and a heat transfer coefficient is larger than that of the column-like part. Thus, the heating by the band heater 10 is not only performed to the column-like part, but also to the jacket 20. Since the heat transfer coefficient of the jacket 20 is larger than that of the column-like part, a heat is transmitted to the jacket 20 faster than the column-like part. Therefore, in the column-like part, a part without providing the band heater 10 is also heated in an outer periphery covered by the jacket 20. Thus, the number of uses of the band heater 10 can be reduced, thereby reducing a power use amount.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heater device that heats a heated object having a columnar portion and a hot runner device equipped with the heater device.

As an example of a heater device that heats a heated object having a columnar portion, there is a band heater disclosed in Patent Document 1 below. A band heater is a heater device that heats the columnar portion of a heated object by wrapping a thin plate-shaped heater portion around it. Since the heater portion of a band heater typically has a rectangular shape, the heatable range in the axial direction of the columnar portion is unlikely to be wide (Patent Document 1 below; Figure 2).

JP 2022-97720 A

For this reason, when heating the entire axial direction of the columnar portion of the heated object, it is necessary to arrange multiple band heaters in the axial direction of the columnar portion. For example, FIG. 6 of the above-mentioned Patent Document 1 discloses an example in which three band heaters are arranged in a row for the heating barrel of an injection device that has a nozzle at the tip. Some such heating barrels have an even longer axial length, so multiple band heaters may be used.

Band heaters generate heat when power is supplied to the heating elements, such as the heating wires, that make up the heater section. Therefore, increasing the number of band heaters used increases power consumption, which directly leads to an increase in the overall power consumption of the device. Therefore, considering the recent rise in electricity prices, it is desirable to reduce the number of band heaters used and cut power consumption. Furthermore, reducing the number of band heaters used also leads to reduced equipment costs for devices equipped with band heaters, such as hot runner devices.

The present invention has been made to solve the above-mentioned problems, and aims to provide a heater device that can reduce power consumption. It also aims to provide a hot runner device that can reduce power consumption and equipment costs.

In order to achieve the above object, the technical means of claim 1 described in the claims is adopted. According to this means, a heater device for heating a heated object having a columnar portion includes a heat transfer body and a band heater. The columnar portion is a concept that includes not only a solid portion with no space inside, but also a hollow portion with space inside. Therefore, the columnar portion also includes a cylindrical shape and a cylindrical shape. The heat transfer body is provided on the outer periphery of the columnar portion and covers a part or all of the outer periphery. The band heater is thermally coupled to the heat transfer body, and heats the columnar portion indirectly via the heat transfer body, or heats the columnar portion directly without using the heat transfer body. The heat transfer body has a higher thermal conductivity than the columnar portion of the heated object. As a result, heating by the band heater is performed not only on the columnar portion of the heated object but also on the heat transfer body, and since the heat transfer body has a higher thermal conductivity than the columnar portion of the heated object, heat is transferred to the heat transfer body faster than the columnar portion. Therefore, the columnar portion is heated in part or in its entirety, where the heat transfer body is provided and covers the outer periphery, even in areas where the band heater is not provided.

The technical means of claim 2 described in the claims is also adopted. According to this means, in addition to the band heater, another band heater is provided. The other band heater is thermally coupled to the heat transfer body and heats the columnar part indirectly through the heat transfer body, or heats the columnar part directly without the heat transfer body. As a result, the heating by the other band heater is performed not only on the columnar part of the heated body but also on the heat transfer body, and since the heat transfer body has a higher thermal conductivity than the columnar part of the heated body, heat is transferred to the heat transfer body faster than the columnar part. For example, the band heater described in claim 1 (hereinafter referred to as "one band heater" in the [Means for solving the problem] and [Effects of the invention] columns) is arranged on one end side of the columnar part, the other band heater is arranged on the other end side of the columnar part, and a heat transfer body is arranged between the one band heater and the other band heater. As a result, the columnar part is heated in part or all of the outer periphery covered by the heat transfer body, even between the two band heaters where no band heater is provided.

The technical means of claim 3 described in the claims is also adopted. According to this means, a hot runner device equipped with the heater device described in claim 1 or 2 has a nozzle that injects molten resin into an injection mold. The object to be heated is this nozzle, and the columnar portion is the cylindrical portion of this nozzle. As a result, heating by the band heater is performed not only on the columnar portion of the nozzle, but also on the heat transfer body, and since the heat transfer body has a higher thermal conductivity than the columnar portion of the nozzle, heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated in part or all of its outer periphery covered by the heat transfer body, even in parts where no band heater is provided (even between one band heater and another band heater).

In the invention of claim 1, the band heater heats not only the columnar portion of the heated object, but also the heat transfer body, and since the heat transfer body has a higher thermal conductivity than the columnar portion of the heated object, heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated in part or all of the outer periphery covered by the heat transfer body, even in parts where the band heater is not provided. This makes it possible to reduce the number of band heaters used, thereby reducing power consumption.

In the invention of claim 2, heating by the other band heater is also performed on the heat transfer body in addition to the columnar portion of the heated object, and since the heat transfer body has a higher thermal conductivity than the columnar portion of the heated object, heat is transferred to the heat transfer body faster than to the columnar portion. In the previous example, the columnar portion is heated in part or all of the outer periphery covered by the heat transfer body, even between the two band heaters where no band heater is provided. Therefore, it is possible to reduce the number of band heaters used, and therefore power consumption can be reduced.

In the invention of claim 3, the band heater heats not only the columnar portion of the nozzle but also the heat transfer body, and since the heat transfer body has a higher thermal conductivity than the columnar portion of the nozzle, heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated in part or all of the outer periphery of the nozzle covered by the heat transfer body, even in parts where no band heater is provided (even between one band heater and another band heater). This makes it possible to reduce the number of band heaters used, thereby reducing power consumption and equipment costs.

1 is a perspective view showing a first configuration example of a heater device according to an embodiment of the present invention; FIG. 11 is a perspective view showing a second configuration example of a heater device according to an embodiment of the present invention. 3A is a perspective view of a jacket constituting the heater device of this embodiment, and FIG 3B is a side view seen from the direction of the arrow 3B in FIG 3A. FIG 3C is a plan view seen from the direction of the arrow 3C in FIG 3A. 4A is a perspective view of a jacket cover constituting the heater device of this embodiment, and FIG 4B is a side view seen from the direction of the arrow 4B in FIG 4A. FIG 4C is a plan view seen from the direction of the arrow 4C in FIG 4A. FIG. 1 is a schematic diagram showing an example of the configuration of a hot runner device and related devices according to an embodiment of the present invention. 1A to 1C are schematic diagrams showing configuration examples 1 and 2 of a heater device according to an embodiment of the present invention and other variations.

Below, an embodiment of the heater device of the present invention and a hot runner device equipped with the same will be described with reference to the drawings. In this embodiment, an example will be described in which the band heater of the present invention is provided in, for example, the injection nozzle of a hot runner device constituting an injection molding machine. In this specification, the Z-axis direction (the longitudinal direction of the injection nozzle) in the coordinate axis display shown in Figures 1 to 4 is sometimes referred to as the "axial direction", and directions perpendicular to the Z-axis, such as the X-axis and Y-axis directions, are sometimes referred to as the "radial direction". Furthermore, the tip direction of the Z-axis is sometimes referred to as the "upward direction", the base end direction is sometimes referred to as the "downward direction", and directions around the Z-axis are sometimes referred to as the "circumferential direction".

As shown in FIG. 1, the heater device 1 of this embodiment heats the injection nozzle 60 of the hot runner device 50 described later, and is composed of two band heaters 10a and 10b and a jacket 20. The band heaters 10a and 10b are similarly configured, and are collectively referred to as the "band heater 10." The configuration of the hot runner device 50 and the like will be described later with reference to FIG. 5. In FIG. 1, the cylindrical portion 61 (heated object) of the injection nozzle 60 is represented by a two-dot chain line as part of the injection nozzle 60. The tip portion 62 of the injection nozzle 60 and the accommodation hole 72 of the plate 70 in which the injection nozzle 60 is accommodated are not shown except in FIG. 5.

The band heaters 10a and 10b that make up the heater device 1 are composed of a cover portion 12 and a heater portion 13. In the heater device 1 of this embodiment, the outer periphery of the cylindrical portion 61 of the injection nozzle 60 is covered with a jacket 20, and the band heaters 10a and 10b are attached so as to further cover both ends of the jacket 20. In other words, the band heater 10 is indirectly attached to the injection nozzle 60 via the jacket 20, with the cover portion 12 covering the jacket 20 so as to surround the heater portion 13.

The cover part 12 is, for example, a plate member having a rectangular shape made of stainless steel (e.g., SUS304), and the plate thickness is set to 0.5 mm. In this embodiment, the cover part 12 is formed in a cylindrical shape with a slit in the axial direction like the letter C of the alphabet, and terminal loops 12a folded back in a roll shape are formed on both ends. These terminal loops 12a accommodate fastening bars 18. The fastening bars 18 are formed with a through hole through which the bolt 19 can be inserted and a female screw hole into which the bolt 19 can be screwed. The bolt 19 that passes through the fastening bar 18 of one terminal loop 12a is screwed into the fastening bar 18 of the other terminal loop 12a, and the bolt 19 is rotated in the screw tightening direction. This makes it possible to fasten the heater part 13 accommodated inside the cover part 12 to the jacket 20 that covers the cylindrical part 61 of the injection nozzle 60.

A wiring window 12b is formed in the center of the cover section 12 in the longitudinal direction, in the shape of a rounded rectangle with rounded corners. This wiring window 12b is a through hole through which the electrical wiring (not shown) connected to the heater section 13 can be inserted and drawn out to the outside. The heater section 13 is a heat generating section having a substantially cylindrical shape, and is composed of a heater element sandwiched between a metallic inner tube plate and an outer tube plate. These are not shown in the figure. The aforementioned electrical wiring is connected to the heater element, and it is configured so that single-phase AC power of, for example, 200V to 300V can be supplied from an external power supply source.

A spacer 17 is attached to the inner peripheral surface of the cover part 12. The spacer 17 is, for example, a cylindrical pipe made of stainless steel (e.g., SUS304) with an outer diameter of about 3 mm, and has an axial length that is approximately the same as the length of the cover part 12 in the Z-axis direction. In this embodiment, the spacer 17 is fixed by welding at both ends to the inner peripheral surface of the cover part 12, and is provided, for example, at four locations at intervals of about 90 degrees around the circumference of the cover part 12. By providing these spacers 17 on the inside of the cover part 12, an air gap is formed between the heater part 13 located further inside. Therefore, the heat generated from the heater part 13 is less likely to be transmitted to the cover part 12. Note that if there is no need to form such an air gap, the spacer 17 may be omitted.

The jacket 20 is, for example, a cylindrical tubular plate member made of aluminum. Its details are shown in FIG. 3, so from here on, we will also refer to FIG. 3 for explanation. As shown in FIG. 3, in this embodiment, the jacket 20 is composed of a jacket body 21 having a cylindrical shape and a gap 23 formed in the axial direction. In other words, the jacket body 21 of the jacket 20 is formed in a cylindrical shape with one gap 23 in the axial direction, like the letter C of the alphabet.

The axial length and inner diameter of the jacket 20 are set arbitrarily based on the length and outer diameter of the cylindrical portion 61 of the injection nozzle 60. In this embodiment, the axial length of the jacket 20 is set to, for example, about 100 mm, and the inner diameter is set to, for example, about 40 mm, and the plate thickness is set to, for example, about 2 mm. The gap 23 is intended to absorb the error between the inner diameter of the jacket 20 and the outer diameter of the cylindrical portion 61 of the injection nozzle 60 to which the jacket 20 is intended to be attached, and in this embodiment, a gap space equivalent to an arc of, for example, 8 to 10% is formed as a percentage of the entire circumference of the cylindrical shape. When the inner diameter is about 40 mm, the gap 23 is set to, for example, about 10 mm.

The heater device 1 of this embodiment is equipped with such a band heater 10 and jacket 20, and after covering the cylindrical portion 61 of the injection nozzle 60 with the jacket 20, the band heater 10a is inserted into one end of the jacket 20 and the band heater 10b is inserted into the other end, and the bolts 19 are tightened. As a result, when the heater portion 13 pressed against the cover portion 12 of the band heater 10 presses the outer peripheral surface 21b of the jacket body 21, the inner peripheral surface 21a comes into contact with the outer peripheral surface while further pressurizing the outer periphery of the cylindrical portion 61, and the band heater 10 is attached to the injection nozzle 60 via the jacket 20.

When power is supplied to the band heater 10 from an external power source, the heater section 13 starts to generate heat, and the heat of the heater section 13 is transferred to the cylindrical section 61 of the injection nozzle 60 via the jacket 20, heating the cylindrical section 61. In other words, the heater section 13 is thermally coupled to the jacket 20, and indirectly heats the cylindrical section 61 via the jacket 20. The jacket 20 that covers the cylindrical section 61 of the injection nozzle 60 is made of aluminum (thermal conductivity 236 W/(m·K)), and its thermal conductivity is greater than that of the cylindrical section 61 of the injection nozzle 60 (e.g., made of carbon steel (thermal conductivity 44 W/(m·K)).

As a result, the band heater 10 heats not only the cylindrical portion 61 but also the jacket 20, and since the jacket 20 has a higher thermal conductivity than the cylindrical portion 61, heat is transferred to the jacket 20 faster than to the cylindrical portion 61. Therefore, the cylindrical portion 61 is heated even in the portion where the band heater 10 is not provided on the outer peripheral surface covered by the jacket 20. Therefore, even if there is a portion where the band heater 10 is not provided in the range of the cylindrical portion 61 of the injection nozzle 60 covered by the jacket 20, that portion is also heated by the adjacent band heater 10 via the jacket 20. Therefore, it is possible to reduce the number of band heaters 10 used, and therefore power consumption can be reduced.

Next, the heater device 2 of this embodiment will be described with reference to FIG. 2. As shown in FIG. 2, the heater device 2 of this embodiment also heats the injection nozzle 60 of the hot runner device 50 described later, similar to the heater device 1 described above. The heater device 2 is composed of one band heater 10, a jacket 20, and a jacket cover 30. The band heater 10 is configured similarly to the band heaters 10a and 10b described above. The band heater 10 constituting the heater device 2 is attached directly to the cylindrical portion 61 of the injection nozzle 60 without contacting the jacket 20. In other words, the band heater 10 is attached to the injection nozzle 60 so as to heat the cylindrical portion 61 directly, without going through the jacket 20.

The jacket cover 30 is, for example, a cylindrical plate member made of stainless steel. Its details are shown in Figure 4, so from here on, we will also refer to Figure 4 for explanation. Note that in Figures 4(A) and 4(B), parts of the cover body 31, spacer 35, etc. are omitted in the axial direction (Z-axis direction). In particular, in Figure 4(A), it appears that there are two cover bodies 31, one with a long axial length and one with a short axial length, but please note that these are one body and the gap between them is due to omission in the illustration.

As shown in FIG. 4, the jacket cover 30 covers the outer periphery of the jacket 20 and presses the jacket 20 radially inward to ensure contact between the inner periphery 21a of the jacket body 21 and the outer periphery of the cylindrical portion 61. Therefore, except for the fact that it has an inner diameter larger than the outer diameter of the jacket body 21, has a long axial length, has terminal loops 32, 33 at multiple axial locations, and does not have a wiring window 12b, it is configured in substantially the same manner as the cover portion 12 of the band heater 10 described above.

That is, the jacket cover 30 is, for example, a wide rectangular plate member made of stainless steel (e.g., SUS304), and the plate thickness is set to 0.5 mm. In this embodiment, the cover body 31 of the jacket cover 30 is formed in a cylindrical shape with a slit in the axial direction like the letter C, and terminal loops 32, 33 folded back in a roll shape are formed on both ends.

The terminal loops 32, 33 are provided in a plurality of axial positions according to the axial length of the cover body 31. In the example shown in FIG. 2, the terminal loops 32, 33 are provided in two positions, but there may be three or more positions. The terminal loops 32, 33 may be provided continuously from one end side to the other end side without being divided in the axial direction. The fastening bar 36 is accommodated in these terminal loops 32, 33. The fastening bar 36 is formed with a through hole through which the bolt 37 can be inserted and a female screw hole into which the bolt 37 can be screwed. The bolt 37 that passes through the fastening bar 36 of the terminal loop 33 is screwed into the fastening bar 36 of the terminal loop 32, and the bolt 37 is rotated in the screw tightening direction. This makes it possible to tighten and fix the jacket 20 accommodated inside the cover body 31 to the cylindrical portion 61 of the injection nozzle 60.

A spacer 35 is attached to the inner peripheral surface of the cover body 31. The spacer 35 is, for example, a cylindrical pipe made of stainless steel (e.g., SUS304) with an outer diameter of about 3 mm, and has an axial length that is approximately the same as the length of the cover body 31 in the Z-axis direction. In this embodiment, the spacer 35 is fixed by welding at both ends to the inner peripheral surface 31a of the cover body 31, and is provided, for example, at four locations at intervals of about 90 degrees in the circumferential direction of the cover body 31. By providing these spacers 35 on the inside of the cover body 31, an air gap is formed between the outer peripheral surface 21b of the jacket 20 located further inside and the inner peripheral surface 31a of the cover body 31. Therefore, the heat transferred from the band heater 10 to the jacket 20 is less likely to be transferred to the cover body 31.

The heater device 2 of this embodiment includes the band heater 10, jacket 20, and jacket cover 30. After covering the cylindrical portion 61 of the injection nozzle 60 with the jacket 20, the jacket 20 is further covered with the jacket cover 30. Then, the bolts 37 of the jacket cover 30 are tightened. As a result, the cover body 31 of the jacket cover 30 presses the outer peripheral surface 21b of the jacket 20, so that the jacket 20 is attached to the injection nozzle 60 with its inner peripheral surface 21a in contact with the outer peripheral surface of the cylindrical portion 61. In addition, the band heater 10 is inserted into a position of the cylindrical portion 61 that is not covered by the jacket 20 in the axial direction of the injection nozzle 60 and is adjacent to the jacket 20 (the portion adjacent to the cylindrical portion 61), and the bolts 19 are tightened. As a result, the heater part 13, which is pressed against the cover part 12 of the band heater 10, comes into contact with the outer periphery of the cylindrical part 61 while applying pressure to the outer periphery, and the band heater 10 is directly attached to the injection nozzle 60 at a position adjacent to the jacket 20.

When power is supplied to the band heater 10 from an external power supply source, the heater section 13 starts to generate heat, and at the position where the band heater 10 is attached, the heat of the heater section 13 is directly transferred to the cylindrical section 61 of the injection nozzle 60, heating the cylindrical section 61. In other words, the heater section 13 heats the cylindrical section 61 directly, without going through the jacket 20. Also, even at a position where the band heater 10 is not attached, the heat of the heater section 13 is transferred to the cylindrical section 61 of the injection nozzle 60 through the adjacent jacket 20, heating the cylindrical section 61. In other words, the heater section 13 is thermally coupled to the jacket 20 via the cylindrical section 61, and indirectly heats the cylindrical section 61 via the jacket 20. The jacket 20 that covers the cylindrical portion 61 of the injection nozzle 60 is made of aluminum (thermal conductivity 236 W/(m·K)), and its thermal conductivity is greater than that of the cylindrical portion 61 of the injection nozzle 60 (e.g., made of carbon steel (thermal conductivity 44 W/(m·K)).

As a result, compared to the heater device 1 described above, the efficiency of heat transfer and heat conduction is reduced by passing from the heater section 13 through the cylindrical section 61, but heating by the band heater 10 is performed not only on the cylindrical section 61 but also on the jacket 20. Since the jacket 20 has a higher thermal conductivity than the cylindrical section 61, heat is transferred to the jacket 20 faster than to the cylindrical section 61. Therefore, the cylindrical section 61 is heated even in the part where the band heater 10 is not provided on the outer peripheral surface covered by the jacket 20. Therefore, even if there is a part where the band heater 10 is not provided in the range of the cylindrical section 61 of the injection nozzle 60 covered by the jacket 20, that part is also heated by the adjacent band heater 10 through the jacket 20. Therefore, it is possible to reduce the number of band heaters 10 used, and therefore it is possible to reduce power consumption.

When the heater devices 1 and 2 configured in this way are applied to a hot runner device 50, it is possible to configure it as shown in FIG. 5, for example. The hot runner device 50 constitutes an injection molding machine that molds resin products. As shown in FIG. 5, in this embodiment, the hot runner device 50 is mainly composed of a manifold 51 having a flow path 52 for molten resin inside, a nozzle touch 53 that receives the molten resin pressure-fed from the outside and guides it to the flow path 52, and an injection nozzle 60 that ejects the molten resin flowing through the flow path 52 of the manifold 51 into a mold (not shown). The manifold 51 is equipped with heaters (not shown) at multiple locations along the flow path 52. The manifold 51 is also attached to a plate 70 having a housing hole 72 in a main body 71 that houses the injection nozzle 60, via a spacer 58 and a fastening bolt 59.

The injection nozzle 60 is mainly composed of a cylindrical portion 61 and a tip portion 62, and in this embodiment, it is configured to be accommodated in an accommodation hole 72 of a plate 70, and the tip portion 62 can be connected to a cavity of a mold not shown. The cylindrical portion 61 of the injection nozzle 60 is formed in a cylindrical shape having a flow path for molten resin inside, and the heater device 1 of this embodiment is attached to the outer periphery of the cylindrical portion 61. The heater device 1 heats the cylindrical portion 61 to a predetermined temperature, thereby making it possible to maintain the temperature of the molten resin flowing through the flow path in the cylindrical portion 61 at an appropriate value. In the example shown in FIG. 5, the heater device 1 shown in FIG. 1 is attached to the cylindrical portion 61, but for example, the heater device 2 shown in FIG. 2 may be attached to the cylindrical portion 61.

In addition, variations in the combination of the band heater 10 and the jacket 20, including the heater devices 1 and 2 described above, are illustrated, for example, as shown in FIG. 6. That is, the heater device 1 shown in FIG. 1 is configured as shown in FIG. 6(A), but as shown in FIG. 6(B), the band heater 10 does not necessarily have to be provided on both sides of the jacket 20, and may be configured to be provided on either one side. Also, the band heater 10 does not necessarily have to be provided on both ends or one end of the jacket 20, and may be configured to be provided at one location approximately in the center of the axial direction of the jacket 20, as shown in FIG. 6(C). Furthermore, although not shown, a configuration combining FIG. 6(A) and FIG. 6(C) may be used, that is, the band heater 10 may be provided at a total of three locations, at both ends and approximately in the center of the jacket 20.

The heater device 2 shown in FIG. 2 is configured as shown in FIG. 6(E), but as shown in FIG. 6(D), it may be configured with band heaters 10a, 10b on both sides of the jacket 20. It may also be configured with jackets 20a, 20b on both sides of the band heater 10. Although not shown, it may be configured by combining FIG. 6(D) and FIG. 6(F), that is, by providing band heaters 10 in a total of three locations, approximately in the center of FIG. 6(F) and at both ends of the jackets 20a, 20b in the same figure (band heater 10a, jacket 20a, band heater 10, jacket 20b, band heater 10b).

As with the heater device 1 in FIG. 6(A), in the above-mentioned FIG. 6(B) and FIG. 6(C), and as with the heater device 2 in FIG. 6(E), in the above-mentioned FIG. 6(D) and FIG. 6(F), it is possible to reduce the number of band heaters 10 used, thereby reducing power consumption.

As described above, the heater devices 1 and 2 of this embodiment include a band heater 10 and a jacket 20. The jacket 20 is provided on the outer periphery of the cylindrical portion 61 of the injection nozzle 60 and covers part or all of the outer periphery. The band heater 10 is thermally coupled to the jacket 20 and heats the cylindrical portion 61 indirectly via the jacket 20 or heats the cylindrical portion 61 directly without passing through the injection nozzle 60. The jacket 20 is made of aluminum (thermal conductivity 236 W/(m·K)), for example, and has a higher thermal conductivity than the cylindrical portion 61 (made of carbon steel (thermal conductivity 44 W/(m·K)). As a result, heating by the band heater 10 is performed not only on the cylindrical portion 61 but also on the jacket 20, and since the jacket 20 has a higher thermal conductivity than the cylindrical portion 61, heat is transferred to the jacket 20 faster than to the cylindrical portion 61. Therefore, the cylindrical portion 61 is heated in part or all of its outer periphery covered by the jacket 20, even in areas where the band heater 10 is not provided. This makes it possible to reduce the number of band heaters 10 used, thereby reducing power consumption.

In addition, the heater devices 1 and 2 of this embodiment are provided with another band heater 10b in addition to the band heater 10a. The other band heater 10b is thermally coupled to the jacket 20 and indirectly heats the cylindrical portion 61 of the injection nozzle 60 via the jacket 20, or directly heats the cylindrical portion 61 without going through the jacket 20. As a result, the heating by the other band heater 10b is also performed on the jacket 20 in addition to the cylindrical portion 61, and since the jacket 20 has a higher thermal conductivity than the cylindrical portion 61 (e.g., made of carbon steel (thermal conductivity 44 W/(m·K)), heat is transferred to the jacket 20 faster than to the cylindrical portion 61. As a result, the cylindrical portion 61 is heated by a part or all of the outer periphery covered by the jacket 20 even between the two band heaters where the band heaters 10a and 10b are not provided. Therefore, it is possible to reduce the number of band heaters 10 used, and therefore the amount of power used can be reduced.

The hot runner device 50 of this embodiment is equipped with a heater device 1 and has an injection nozzle 60 that injects molten resin into an injection mold. The object to be heated by the heater device 1 is this injection nozzle 60, and the columnar portion is the cylindrical portion 61 of this injection nozzle 60. As a result, the band heaters 10a and 10b heat the jacket 20 in addition to the cylindrical portion 61. The jacket 20 has a higher thermal conductivity than the cylindrical portion 61 (e.g., made of carbon steel (thermal conductivity 44 W/(m·K)), so heat is transferred to the jacket 20 faster than to the cylindrical portion 61. Therefore, the cylindrical portion 61 is heated in part or all of its outer periphery covered by the jacket 20, even in the part where the band heaters 10a and 10b are not provided. This makes it possible to reduce the number of band heaters 10a and 10b used, thereby reducing power consumption and equipment costs. Note that in FIG. 5, an injection molding machine equipped with a manifold 51 is illustrated, but if the cylindrical portion 61 of the injection nozzle 60 (a heated body having a columnar portion) needs to be heated, the manifold 51 is not necessarily required.

In the heater device 2 of the present embodiment described above, the spacer 35 made of a cylindrical pipe material is provided on the inner circumferential surface 31a of the cover body 31 of the jacket cover 30 as a separation member. However, the separation member is not limited to this as long as it forms an air gap (space) between the jacket body 21 (heat transfer body) of the jacket 20 and the cover body 31 (cover body). For example, a square pipe material or a solid bar material (round bar or square bar) may be used. Furthermore, if it is possible to form such an air gap, the length of the spacer 35 may be 1/2 or 1/3, and the number of spacers 35 may be three or five. However, as the contact area between the jacket 20 (the jacket body 21) and the jacket cover 30 (the cover body 31) increases through the spacer 35, the width and number of the heat transfer paths that escape from the jacket 20 to the jacket cover 30 through the separation member increase, so it is desirable to keep the length and number to the minimum necessary to stably secure the air gap.

In addition, in the heater device 2 of the present embodiment described above, the jacket cover 30 is configured to have approximately the same axial length as the jacket 20 (heat transfer body) as a cover part that covers part or all of the outer periphery of the heat transfer body, but the axial length may be set to be smaller (shorter) than the heat transfer body. For example, the jacket cover 30 (cover part) may be configured to have the same axial length as the band heater 10 (10a, 10b). In this case, for example, instead of the band heaters 10a, 10b shown in FIG. 1, a jacket cover 30 with a short axial length is attached to cover both ends of the jacket 20.

In addition, in the heater devices 1 and 2 of the present embodiment described above, the jacket body 21 of the jacket 20 is made of aluminum as a heat transfer body, but the material is not limited to aluminum (thermal conductivity 236 W/(m·K)) as long as it has a higher thermal conductivity than the cylindrical portion 61 of the injection nozzle 60. For example, the thermal conductivity of stainless steel is 16.7 to 20.9 W/(m·K), and the thermal conductivity of iron is 83.5 W/(m·K). Therefore, if the cylindrical portion 61 of the injection nozzle 60 is made of stainless steel or iron, the jacket body 21 of the jacket 20 may be made of brass (thermal conductivity: 106 W/(m·K)) or copper (same: 403 W/(m·K)), which has a higher thermal conductivity than these materials.

In addition, in the heater devices 1 and 2 of the present embodiment described above, the jacket body 21 of the jacket 20 is formed as a heat transfer body in a cylindrical shape with one gap 23 in the axial direction, like the letter C of the alphabet, but it is sufficient if it can cover part or all of the outer periphery of the cylindrical part 61 of the injection nozzle 60 (the columnar part of the heated body). For example, the jacket body 21 of the jacket 20 may be formed in a cylindrical shape with no breaks in the axial direction like the gap 23, a cylindrical shape with two gaps in the axial direction such that two semicircular shapes face each other with their openings facing each other, etc.

In addition, in the heater devices 1 and 2 of the present embodiment described above, the case where the heated object is attached to an injection nozzle 60 having a cylindrical portion 61 has been described as an example, but the heated object heated by the heater device of the present invention is not limited to this. The object to which the heater devices 1 and 2 are attached may be a heated object such as an injection nozzle having a prismatic (or rectangular tube) or polygonal prismatic (or polygonal tube) shape, as long as it is a columnar (or cylindrical) body. The heater devices 1 and 2 may also be attached to the heating cylinder of an extrusion molding machine.

Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications or changes to the above specific examples. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. Note that the descriptions in parentheses in the [Explanation of symbols] column may clearly indicate the correspondence between the terms used in each of the above-mentioned embodiments and the terms described in the claims.

REFERENCE SIGNS LIST 1, 2... Heater device 10, 10a, 10b... Band heater 12... Cover portion 13... Heater portion 17... Spacer 20, 20a, 20b... Jacket (heat transfer body)
Reference Signs List 21: Jacket body 21a: Inner peripheral surface 21b: Outer peripheral surface 23: Gap 30: Jacket cover 31: Cover body 31a: Inner peripheral surface 31b: Outer peripheral surface 35: Spacer 50: Hot runner device 51: Manifold 53: Nozzle touch 60: Injection nozzle 61: Cylindrical portion 62: Tip portion 70: Plate 72: Accommodation hole

In order to achieve the above object, the technical means of claim 1 described in the claims is adopted. According to this means, a heater device for heating a heated object having a columnar portion includes a heat transfer body and a band heater. The columnar portion is a concept including not only a solid portion with no space inside, but also a hollow portion with space inside. Therefore, the columnar portion also includes a cylindrical shape and a cylindrical shape. The heat transfer body is provided on the outer periphery of the columnar portion and covers a part or all of the outer periphery. The band heater covers the heat transfer body and is thermally coupled to the heat transfer body, and indirectly heats the columnar portion via the heat transfer body. The heat transfer body has an axial length that is at least twice the axial length of the band heater, and has a thermal conductivity greater than that of the columnar portion of the heated object. As a result, the band heater heats not only the columnar portion of the heated object but also the heat transfer body, and since the axial length of the heat transfer body is at least twice the axial length of the band heater and has a higher thermal conductivity than the columnar portion of the heated object, heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated in a part or all of its outer periphery covered by the heat transfer body even if the area where the band heater is not provided is an area of at least one band heater .

The technical means of claim 2 described in the claims is also adopted. According to this means, in addition to the band heater , another band heater is further provided. The heat transfer body has an axial length of at least three times the axial length of the band heater. The other band heater covers the other end side of the heat transfer body and is thermally coupled to the heat transfer body, and indirectly heats the columnar portion via the heat transfer body. As a result, heating by the other band heater is performed not only on the columnar portion of the heated object but also on the heat transfer body, and since the axial length of the heat transfer body is at least three times the axial length of the band heater and has a higher thermal conductivity than the columnar portion of the heated object, heat is transferred to the heat transfer body faster than the columnar portion. For example, the band heater described in claim 1 (hereinafter referred to as "one band heater" in the columns "Means for solving the problem" and "Effects of the invention") is arranged on one end side of the columnar portion, the other band heater is arranged on the other end side of the columnar portion, and the heat transfer body is arranged between the one band heater and the other band heater. As a result, the columnar portion is heated by part or all of its outer periphery, which is covered by the heat transfer body, even in an area between both band heaters where no band heater is provided and which is the size of one or more band heaters.
The technical means of claim 3 described in the claims is also adopted. According to this means, a heater device for heating a heated object having a columnar portion includes a heat transfer body and a band heater. The columnar portion is a concept including not only a solid portion with no space inside, but also a hollow portion with a space inside. Therefore, the columnar portion also includes a cylindrical shape and a cylindrical shape. The heat transfer body is provided on the outer periphery of the columnar portion and covers a part or all of the outer periphery. The band heater is located adjacent to the heat transfer body in the axial direction of the heated object and directly heats the columnar portion without going through the heat transfer body. The heat transfer body has an axial length equal to or greater than the axial length of the band heater and a thermal conductivity greater than that of the columnar portion. As a result, heating by the band heater is performed not only on the columnar portion of the heated object but also on the heat transfer body, and since the axial length of the heat transfer body is equal to or greater than the axial length of the band heater and has a thermal conductivity greater than that of the columnar portion of the heated object, heat is transferred to the heat transfer body faster than the columnar portion. Therefore, in the columnar portion, a part or all of the outer periphery thereof that is covered by the heat transfer body is heated even if the area where the band heater is not provided is an area equivalent to one or more band heaters.
The technical means of claim 4 described in the claims is also adopted. According to this means, in addition to the band heater, another band heater is provided. The other band heater is located adjacent to the heat transfer body on the opposite side of the band heater in the axial direction of the heated object, and heats the columnar part directly without the heat transfer body. As a result, the heating by the other band heater is performed not only on the columnar part of the heated object but also on the heat transfer body, and since the axial length of the heat transfer body is equal to or longer than that of the band heater and has a higher thermal conductivity than the columnar part of the heated object, heat is transferred to the heat transfer body faster than the columnar part. For example, the band heater described in claim 1 (hereinafter referred to as "one band heater" in the columns "Means for solving the problem" and "Effects of the invention") is arranged at one end of the columnar part, the other band heater is arranged at the other end of the columnar part, and a heat transfer body is arranged between the one band heater and the other band heater. As a result, the columnar portion is heated by part or all of its outer periphery, which is covered by the heat transfer body, even in an area between both band heaters where no band heater is provided and which is the size of one or more band heaters.
The present invention also employs the technical means of claim 5. According to this means, a heat transfer body cover is provided for covering the outer periphery of the heat transfer body.

The technical means of claim 6 described in the claims is also adopted. According to this means, a hot runner device equipped with the heater device according to any one of claims 1 to 4 has a nozzle for injecting molten resin into an injection mold. The object to be heated is the nozzle, and the columnar portion is the cylindrical portion of the nozzle. As a result, heating by the band heater is performed not only on the columnar portion of the nozzle but also on the heat transfer body, and the axial length of the heat transfer body is equal to or longer than the axial length of the band heater, or equal to or longer than two or three times the axial length of the band heater, and has a higher thermal conductivity than the columnar portion of the nozzle, so that heat is transferred faster to the heat transfer body than to the columnar portion. Therefore, the columnar portion is heated even in a part or all of its outer periphery covered by the heat transfer body, where no band heater is provided ( a range of one or more band heaters between one band heater and another band heater).

In the invention of claim 1, the band heater heats not only the columnar portion of the heated object but also the heat transfer body, and the axial length of the heat transfer body is at least twice the axial length of the band heater and has a higher thermal conductivity than the columnar portion of the heated object, so that heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, in part or all of the outer periphery of the columnar portion covered by the heat transfer body, the columnar portion is heated even if the area where the band heater is not provided is an area of more than one band heater . Therefore, the area where the band heater is not provided is heated, and the number of band heaters used can be reduced, so that the amount of power consumption can be reduced.

In the invention of claim 2, heating by the other band heater is also performed on the heat transfer body in addition to the columnar part of the heated object, and the axial length of the heat transfer body is three times or more than the axial length of the band heater, and the heat transfer body has a higher thermal conductivity than the columnar part of the heated object, so that heat is transferred to the heat transfer body faster than the columnar part. In the previous example, the columnar part is heated in part or all of the outer periphery covered by the heat transfer body, even in an area between both band heaters where no band heater is provided and in an area of more than one band heater. Therefore, an area of more than one band heater where no band heater is provided is heated, making it possible to reduce the number of band heaters used, and thus reducing power consumption.
In the invention of claim 3, the band heater heats not only the columnar portion of the heated object but also the heat transfer body, and the axial length of the heat transfer body is equal to or longer than the axial length of the band heater and has a higher thermal conductivity than the columnar portion of the heated object, so that heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated even if the area where the band heater is not provided is an area of more than one band heater in part or all of its outer periphery covered by the heat transfer body. Therefore, the area where the band heater is not provided is heated, and the number of band heaters used can be reduced, so that the amount of power consumption can be reduced.
In the invention of claim 4, heating by the other band heater is also performed on the heat transfer body in addition to the columnar part of the heated object, and the axial length of the heat transfer body is equal to or longer than that of the band heater, and the heat transfer body has a higher thermal conductivity than the columnar part of the heated object, so that heat is transferred to the heat transfer body faster than the columnar part. In the previous example, the columnar part is heated in part or all of the outer periphery covered by the heat transfer body, even in an area between both band heaters where no band heater is provided and in an area of more than one band heater. Therefore, an area of more than one band heater where no band heater is provided is heated, making it possible to reduce the number of band heaters used, and thus reducing power consumption.

In the invention of claim 6 , the band heater heats not only the columnar portion of the nozzle but also the heat transfer body, and the axial length of the heat transfer body is equal to or longer than the axial length of the band heater, or is equal to or longer than two or three times the axial length of the band heater, and has a higher thermal conductivity than the columnar portion of the nozzle, so that heat is transferred to the heat transfer body faster than to the columnar portion. Therefore, the columnar portion is heated even in a part or the whole of the outer periphery of the nozzle covered by the heat transfer body, where the band heater is not provided ( a range of one or more band heaters between one band heater and another band heater). Therefore, it is possible to reduce the number of band heaters used, which leads to a reduction in power consumption and a reduction in equipment costs.

REFERENCE SIGNS LIST 1, 2... Heater device 10, 10a, 10b... Band heater 12... Cover portion 13... Heater portion 17... Spacer 20, 20a, 20b... Jacket (heat transfer body)
21... Jacket body 21a... Inner peripheral surface 21b... Outer peripheral surface 23... Gap 30... Jacket cover (heat transfer body cover)
Reference Signs List 31: Cover body 31a: Inner peripheral surface 31b: Outer peripheral surface 35: Spacer 50: Hot runner device 51: Manifold 53: Nozzle touch 60: Injection nozzle 61: Cylindrical portion 62: Tip portion 70: Plate 72: Accommodating hole

Claims (3)

A heater device for heating a heated object having a columnar portion,
a heat transfer body provided on an outer periphery of the columnar portion and covering a part or all of the outer periphery;
a band heater that is thermally coupled to the heat transfer body and heats the columnar portion indirectly via the heat transfer body or directly without via the heat transfer body;
The heater device according to claim 1, wherein the heat transfer body has a thermal conductivity greater than that of the columnar portion. In addition to the band heater, another band heater is provided,
2. The heater device according to claim 1, wherein the other band heater is thermally coupled to the heat conductor and heats the columnar portion indirectly via the heat conductor or directly without via the heat conductor. A hot runner device including the heater device according to claim 1 or 2, the hot runner device having a nozzle for injecting molten resin into an injection mold,
4. A hot runner apparatus comprising: a nozzle; and a columnar portion of the nozzle.

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