JP2013173257A - Induction heating device for cylinder of molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating device for a cylinder of a molding machine which is capable of efficiently heating corresponding to a temperature characteristic of a raw material to be used while avoiding an excessive temperature rise.SOLUTION: An induction heating device 1 comprises a high efficiency heating member 10 for efficiently heating a cylinder 31 and an excessive temperature rise preventing member 20 for heating the cylinder 31 to avoid an excessive temperature rise. The high efficiency heating member 10 is provided with a heat insulating material 11 covering the outer circumferential surface of the cylinder 31 over the whole and a first induction heating coil 12 wound around the outside of the heat insulating material 11. The excess temperature rise preventing member 20 is provided with a second induction heating coil 21 wound around the cylinder 31 and a pressing plate 22 pressing the second induction heating coil 21 from the outside.

Description

  The present invention relates to an induction heating device for a molding machine cylinder.

  Induction heating may be employed as a cylinder heating means in an injection molding machine, an extrusion molding machine, or the like. Induction heating has an advantage that the raw material can be melted with high thermal efficiency because the cylinder itself, which is the object to be heated, is heated (see Patent Document 1).

JP 2004-276282 A

  However, when the cylinder is heated by induction heating, there is a problem that overheating is likely to occur, and molding defects due to burning of the raw material are likely to occur. In particular, this problem becomes significant when a raw material such as an amorphous resin that tends to increase in temperature is used.

  The present invention has been completed based on the above circumstances, and can be used for a molding machine cylinder that can efficiently perform heating while avoiding excessive temperature rise according to the temperature characteristics of the raw material used. An object is to provide an induction heating apparatus.

  An induction heating device for a molding machine cylinder according to the present invention includes a cylindrical cylinder, a raw material supply unit that is disposed at one end of the cylinder and supplies the material into the cylinder, and is disposed at the other end of the cylinder. In a molding machine comprising a nozzle for supplying heated and melted material to a mold, an induction heating device for a molding machine cylinder mounted on the outer periphery of the cylinder to heat the cylinder, the axial direction of the cylinder A plurality of members mounted in parallel in the direction along the high efficiency heating member mounted on the raw material supply unit side region in the cylinder, and the nozzle side region in the cylinder An overheat-preventing member attached to the heat-insulating member, wherein the high-efficiency temperature-raising member includes a heat-retaining member that covers an outer peripheral surface of the cylinder, and a first induction heating coil that is wound around the heat-retaining member; A second induction heating coil that is wound around the outer peripheral surface of the cylinder with a certain gap, and the second induction heating coil with respect to the outer peripheral surface of the cylinder. And a coil holding member for holding a certain gap.

  In the induction heating device for a molding machine cylinder of the present invention, the excessive temperature rise prevention member may include a pressing portion that presses the second induction heating coil from the outer peripheral direction.

  In the induction heating device for a molding machine cylinder of the present invention, the excessive temperature rise prevention member may include a cooling member that sends a cooling gas into a gap between the cylinder and the second induction heating coil.

  Further, the molding machine of the present invention includes a cylindrical cylinder, a raw material supply unit that is disposed at one end of the cylinder and supplies the material to the inside of the cylinder, and is disposed at the other end of the cylinder for heating. A molding apparatus main body comprising a nozzle for supplying molten material to a mold, and a molding machine cylinder induction heating apparatus mounted on the outer periphery of the cylinder to heat the cylinder, the molding machine cylinder induction heating apparatus Is provided with a plurality of members mounted in parallel in a direction along the axial direction of the cylinder, the plurality of members is a high-efficiency temperature rising member mounted in the raw material supply unit side region in the cylinder, An excessive temperature rise prevention member mounted on the nozzle side of the cylinder, and the high efficiency temperature rise member is wound around the heat insulation member and a heat insulation member that covers an outer peripheral surface of the cylinder. A first induction heating coil, and the excessive temperature rise prevention member is wound around the outer peripheral surface of the cylinder with a certain gap between the second induction heating coil and the second induction heating coil. And a coil holding member that holds the cylinder in a state where a certain gap is left between the outer peripheral surface of the cylinder.

  According to the present invention, heating can be performed efficiently while avoiding excessive temperature rise, depending on the temperature characteristics of the raw material used.

The perspective view which shows a mode that the induction heating apparatus for molding machines cylinder of Embodiment 1 was mounted | worn to the cylinder. AA sectional view of FIG. BB sectional view of FIG. The partial enlarged view which shows a mode that the 2nd induction heating coil was hold | maintained on the cylinder outer peripheral surface with the pressing plate. The side view which shows a mode that the induction heating apparatus for molding machines cylinder of Embodiment 2 was mounted | worn to the cylinder. The second induction heating coil is held on the outer peripheral surface of the cylinder by the coil holder, and a partially enlarged view showing a state in which air is caused to flow in the gap between the outer peripheral surface of the cylinder and the second induction heating coil by the slit ring. CC sectional view of FIG. Perspective view of excessive temperature rise prevention member

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS.

  A molding machine cylinder induction heating device (hereinafter abbreviated as “induction heating device”) 1 of this embodiment is mounted on a cylinder 31 of an injection device 30 in an injection molding machine 2. FIG. 1 shows an injection device 30 for melting raw material resin and supplying it to a mold, and an induction heating device 1 attached to the injection device 30. The injection device 30 includes a cylinder 31. A screw (not shown) for extruding the raw material resin passes through the cylinder 31, and this screw is driven to rotate by a motor (not shown). Further, a raw material supply part 32 for supplying a raw material resin into the cylinder 31 is arranged at the base end part of the cylinder 31, and a nozzle 34 is attached to the distal end part of the cylinder 31 via a nozzle attachment part 33.

  The induction heating device 1 is composed of two types of members. One member is the high-efficiency heating member 10 for heating the cylinder 31 efficiently. The high-efficiency heating member 10 includes a heat insulating material 11 that covers the outer peripheral surface of the cylinder 31 over the entire circumference, a first induction heating coil 12 wound around the heat insulating material 11, and the first induction heating coil. 12 and an inverter 13 that controls the energization of the first induction heating coil 12. As the heat insulating material 11, for example, a glass felt pipe can be suitably used. Moreover, as the 1st induction heating coil 12, what was common as an induction heating coil, such as what wound the litz wire, can be used, for example.

  The other member is an excessive temperature rise prevention member 20 that performs heating so that the cylinder 31 does not rise excessively. The excessive temperature rise prevention member 20 is connected to the second induction heating coil 21 wound around the cylinder 31, a holding plate 22 that holds the second induction heating coil 21 from the outside, and the second induction heating coil 21. And an inverter 24 that controls energization of the second induction heating coil 21.

  The second induction heating coil 21 has an inner diameter that is slightly larger than the outer diameter of the cylinder 31, and is mounted so as to hold a predetermined gap between the second induction heating coil 21 and the outer peripheral surface of the cylinder 31. As the 2nd induction heating coil 21, like the 1st induction heating coil 12, what was common as an induction heating coil, such as what wound the litz wire, can be used.

  The pressing plate 22 is formed in a long plate shape as a whole by, for example, a ceramic material having heat insulation properties. The length of the pressing plate 22 is slightly longer than the length of the second induction heating coil 21, and the width thereof is slightly larger than the distance from the outer peripheral surface of the cylinder 31 to the outer peripheral surface of the second induction heating coil 21. At one end in the width direction, a plurality of slits 23 are formed side by side along the length direction of the pressing plate 22 with a certain interval. The depth of each slit 23 is substantially equal to the distance from the outer peripheral surface of the cylinder 31 to the outer peripheral surface of the second induction heating coil 21. The width of the slit 23 is substantially equal to the diameter of the coil wire constituting the second induction heating coil 21 so that the coil wire can be held almost tightly inside. Furthermore, the pitch of the slits 23 (the distance between the center lines of adjacent slits) is set equal to the pitch of the second induction heating coil 21.

  A plurality of the pressing plates 22 (four in the present embodiment) are arranged on the outer peripheral surface of the cylinder 31 so as to be equally spaced in the circumferential direction. Each pressing plate 22 is erected in such a manner that the plate surface is in a direction along the radial direction of the cylinder 31 and the end portion on the side where the slit 23 is formed contacts the outer peripheral surface of the cylinder 31. And the coil wire of the 2nd induction heating coil 21 is accommodated so that it may be pushed to the back end of each slit 23. FIG. Thereby, the 2nd induction heating coil 21 is hold | maintained in the state wound with a fixed distance with respect to the outer peripheral surface of the cylinder 31. FIG.

  When the induction heating apparatus 1 configured as described above is attached to the cylinder 31 of the injection molding machine, the high-efficiency heating member 10 is attached to the region on the raw material supply unit 32 side on the outer peripheral surface of the cylinder 31 and excessively heated. The temperature rise prevention member 20 is mounted on the outer peripheral surface of the cylinder 31 in the region on the nozzle mounting portion 33 side. In the present embodiment, three high-efficiency heating members 10 are mounted from the end on the raw material supply unit 32 side on the outer peripheral surface of the cylinder 31, and two excessive temperature rise prevention members 20 are disposed closer to the nozzle mounting unit 33 than that. Is installed.

  In order to supply the material to the mold by the injection device 30 to which the induction heating device 1 is mounted in this way, first, the high-efficiency heating member 10 and the induction heating coils 12 and 21 of the excessive temperature rise prevention member 20 are energized. Then, the cylinder 31 is heated. When the temperature of the cylinder 31 is increased to a predetermined temperature, the raw material resin is introduced into the cylinder 31 from the raw material supply unit 32. The charged raw material resin is melted inside the cylinder 31, sent to the nozzle by the rotation of the screw, and injected into the mold.

  At this time, the high-efficiency heating member 10 is mounted in a region near the raw material supply unit 32 in the cylinder 31. For this reason, the heat release from the cylinder 31 is suppressed by the heat insulating material 11, and the raw material resin is efficiently heated.

  On the other hand, in the area close to the nozzle mounting portion 33 in the cylinder 31, it is sufficient to hold the molten resin in a molten state already sufficiently, and the heating is performed in the same manner as the area close to the raw material supply portion 32. However, problems such as burning of the resin due to excessive temperature rise occur. For this reason, the excessive temperature rise prevention member 20 is attached. The excessive temperature rise prevention member 20 is wound around the second induction heating coil 21 without a heat insulating material interposed between the overheat prevention member 20 and the cylinder 31. For this reason, a certain amount of heat is dissipated from the surface of the cylinder 31, and an excessive temperature rise is prevented.

  Further, each high efficiency heating member 10 and excessive temperature rise prevention member 20 are provided with inverters 13 and 24 for controlling energization to the induction heating coils 12 and 21, respectively. For this reason, the output of the induction heating coils 12 and 21 can be individually controlled in accordance with the thermal characteristics of the raw material used.

  As a result, it is possible to achieve both high-efficiency heating on the side close to the raw material supply unit 32 in the cylinder 31 and suppression of occurrence of problems due to excessive temperature rise on the side close to the nozzle mounting unit 33.

  Here, in the region where the overheat prevention member 20 is mounted in the cylinder 31, the second induction heating coil 21 is wound in a state in which no heat insulating material is interposed between the cylinder 31 and the cylinder 31. For this reason, the second induction heating coil 21 directly receives heat radiation from the cylinder 31. When the second induction heating coil 21 expands due to this heat and the gap width (the distance between the surface of the cylinder 31 and the coil) varies, the heating may become unstable. For this reason, the 2nd induction heating coil 21 is hold | suppressed from the outer peripheral side with the some pressing board 22, and the fluctuation | variation of the gap width is suppressed. Thereby, heating can be performed stably.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described in detail with reference to FIGS.

  A molding machine cylinder induction heating device (hereinafter abbreviated as “induction heating device”) 40 according to this embodiment is mounted on the cylinder 31 of the injection device 30 in the injection molding machine 2 as in the first embodiment. It is. Since the injection device 30 has the same configuration as that of the first embodiment, the same reference numerals are given and description thereof is omitted.

  As in the first embodiment, the induction heating device 40 includes a high-efficiency heating member 10 for efficiently heating the cylinder 31 and an excessive temperature rise prevention member 41 that performs heating so that the cylinder 31 does not overheat. Is done. Since the high-efficiency heating member 10 has the same configuration as that of the first embodiment, the same reference numerals are given and description thereof is omitted.

  The overheating prevention member 41 is connected to the coil holder 42 mounted on the outer periphery of the cylinder 31, the second induction heating coil 46 wound around the coil holder, and the second induction heating coil 46. An inverter 47 that controls energization of the second induction heating coil 46 and a slit ring 48 for flowing cooling gas through a gap between the outer peripheral surface of the cylinder 31 and the second induction heating coil 46 are provided.

  The coil holder 42 includes a pair of ring portions 43 and a plurality of connecting portions 44 spanned between the pair of ring portions. The pair of ring portions 43 are each formed in an annular shape having an inner diameter that is slightly larger than the outer diameter of the cylinder 31. The plurality of connecting portions 44 are formed in a rod shape, and a plurality (six in this embodiment) are arranged so as to be equally spaced in the circumferential direction of the ring portion 43. A plurality of leg portions 45 are provided on the outer surface of the ring portion 43 (the surface on the opposite side to the surface opposite to the other ring portion 43). Each leg portion 45 is formed in an L shape, and is arranged such that one side of the L shape is connected to the outer surface of the ring portion 43 and the other side protrudes toward the cylinder 31 side. A plurality of these leg portions 45 (six in this embodiment) are provided so as to be equally spaced in the circumferential direction of the ring portion 43. As a material of the coil holder 42, for example, an inorganic material having high heat resistance and high dimensional stability (for example, “Rossner board” manufactured by Nikko Kasei Co., Ltd.) can be used.

  The slit ring 48 is disposed between adjacent coil holders 42 or between the coil holder 42 and the high efficiency heating member 10 and is formed in an annular shape having an inner diameter substantially equal to the outer diameter of the cylinder 31. Yes. The inside of the slit ring 48 is hollow around the entire circumference. In the slit ring 48, a slit 49 that allows gas to enter and exit over the entire circumference is formed on the surface facing the overheat prevention member 41. In addition, an inlet 50 that can feed gas into the slit ring 48 is provided at one place on the outer peripheral surface of the slit ring 48. The inflow port 50 is connected to an air supply source such as an air cylinder or an air compressor via a tube.

  When the induction heating device 40 configured as described above is mounted on the cylinder 31, the high-efficiency heating member 10 is mounted on a region on the raw material supply unit 32 side on the outer peripheral surface of the cylinder 31, and an excessive temperature rise prevention member 41 is mounted on the outer peripheral surface of the cylinder 31 in the region on the nozzle mounting portion 33 side. In the present embodiment, one high-efficiency heating member 10 is mounted from the end on the raw material supply unit 32 side on the outer peripheral surface of the cylinder 31, and three excessive temperature rise prevention members 41 are disposed closer to the nozzle mounting unit 33 than that. Is installed.

  In order to supply the material to the mold by the injection device 30 to which the induction heating device 40 is mounted in this way, first, the induction heating coils 12 and 46 of the respective high efficiency heating members 10 and the excessive temperature rise prevention member 41 are energized. Then, the cylinder 31 is heated. When the temperature of the cylinder 31 is increased to a predetermined temperature, the raw material resin is introduced into the cylinder 31 from the raw material supply unit 32. The charged raw material resin is melted inside the cylinder 31, is sent to the nozzle 34 by the rotation of the screw, and is injected into the mold.

  At this time, the high-efficiency heating member 10 is mounted in a region near the raw material supply unit 32 in the cylinder 31. For this reason, the heat release from the cylinder 31 is suppressed by the heat insulating material 11, and the raw material resin is efficiently heated.

  On the other hand, in the area close to the nozzle mounting portion 33 in the cylinder 31, it is sufficient to hold the molten resin in a molten state already sufficiently, and the heating is performed in the same manner as the area close to the raw material supply portion 32. However, problems such as burning of the resin due to excessive temperature rise occur. For this reason, the excessive temperature rise prevention member 41 is attached. The excessive temperature rise prevention member 41 is wound around the second induction heating coil 46 without a heat insulating material interposed between the overheat prevention member 41 and the cylinder 31. For this reason, a certain amount of heat is dissipated from the surface of the cylinder 31, and an excessive temperature rise is prevented.

  Further, a slit ring 48 is disposed between adjacent coil holders 42 or between the coil holder 42 and the high efficiency heating member 10. Air sent from the air supply source is sent into the slit ring 48 and flows out from the slit 49. The air that has flowed out flows through the gap between the outer peripheral surface of the cylinder 31 and the second induction heating coil 46. Thereby, heat dissipation from the surface of the cylinder 31 is promoted, and excessive temperature rise is prevented.

  Further, each high-efficiency heating member 10 and overheat prevention member 41 are provided with inverters 13 and 47 for controlling energization to the induction heating coils 12 and 46, respectively. For this reason, the output of the induction heating coils 12 and 46 can be individually controlled in accordance with the thermal characteristics of the raw material used. As a result, it is possible to achieve both high-efficiency heating on the side close to the raw material supply unit 32 in the cylinder 31 and suppression of occurrence of problems due to excessive temperature rise on the side close to the nozzle mounting unit 33.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the example in which the molding machine is an injection molding machine has been described in the above embodiment, the present invention can be similarly applied even when the molding machine is an extrusion molding machine.
(2) In the first embodiment, three high-efficiency heating members 10 are mounted on the outer peripheral surface of the cylinder 31 from the end on the raw material supply unit 32 side, and two excessive temperature rise preventions are provided on the nozzle mounting unit 33 side. In the second embodiment, one high-efficiency heating member 10 is mounted on the outer peripheral surface of the cylinder 31 from the end on the raw material supply unit 32 side, and three excess heating members 10 are mounted on the nozzle mounting unit 33 side. Although the temperature rise prevention member 41 is attached, the number of the high-efficiency heating member and the excessive temperature rise prevention member to be attached may be arbitrarily set according to the thermal characteristics of the raw material to be used.
(3) In the above embodiment, the case where the raw material to be used is a resin material is exemplified, but the raw material to be used may be a metal material.

1 ... Induction heating device for molding machine cylinder 2 ... Injection molding machine (molding machine)
10 ... High-efficiency temperature raising member 11 ... Insulating material (thermal insulation member)
12 ... 1st induction heating coil 13 ... Inverter (control apparatus)
20 ... Over temperature rise prevention member 21, 46 ... Second induction heating coil 22 ... Holding plate (coil holding member, holding portion)
30 ... Injection device (molding device body)
DESCRIPTION OF SYMBOLS 31 ... Cylinder 32 ... Raw material supply part 34 ... Nozzle 41 ... Over temperature rise prevention member 42 ... Coil holder (coil holding member)
48 ... Slit ring (cooling member)

Claims (4)

A cylindrical cylinder, a raw material supply unit that is disposed at one end of the cylinder and supplies the material to the inside of the cylinder, and a material that is disposed at the other end of the cylinder and is heated and melted is supplied to the mold. In a molding machine comprising a nozzle, an induction heating device for a molding machine cylinder that is mounted on the outer periphery of the cylinder and heats the cylinder,
A plurality of members mounted in parallel in a direction along the axial direction of the cylinder;
The plurality of members include a high-efficiency temperature rising member that is mounted on the raw material supply unit side region of the cylinder, and an excessive temperature rising prevention member that is mounted on the nozzle side region of the cylinder,
The high-efficiency temperature raising member includes a heat retaining member that covers an outer peripheral surface of the cylinder, and a first induction heating coil that is wound around the heat retaining member,
The overheating prevention member is wound around the outer peripheral surface of the cylinder with a constant gap, and the second induction heating coil is fixed with respect to the outer peripheral surface of the cylinder. An induction heating device for a molding machine cylinder, comprising: a coil holding member that holds a gap.   The induction heating device for a molding machine cylinder according to claim 1, wherein the excessive temperature rise prevention member includes a pressing portion that presses the second induction heating coil from an outer peripheral direction.   The induction heating device for a molding machine cylinder according to claim 1, wherein the excessive temperature rise prevention member includes a cooling member that sends a cooling gas into a gap between the cylinder and the second induction heating coil. A cylindrical cylinder, a raw material supply unit that is disposed at one end of the cylinder and supplies the material to the inside of the cylinder, and a material that is disposed at the other end of the cylinder and is heated and melted is supplied to the mold. A molding apparatus body including a nozzle, and an induction heating apparatus for a molding machine cylinder that is mounted on the outer periphery of the cylinder and heats the cylinder,
The molding machine cylinder induction heating device includes a plurality of members mounted in parallel in a direction along the axial direction of the cylinder,
The plurality of members include a high-efficiency temperature rising member that is mounted on the raw material supply unit side region of the cylinder, and an excessive temperature rising prevention member that is mounted on the nozzle side region of the cylinder,
The high-efficiency temperature raising member includes a heat retaining member that covers an outer peripheral surface of the cylinder, and a first induction heating coil that is wound around the heat retaining member,
The overheating prevention member is wound around the outer peripheral surface of the cylinder with a constant gap, and the second induction heating coil is fixed with respect to the outer peripheral surface of the cylinder. A molding machine comprising: a coil holding member that holds a gap.

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