JP2011079015A - Warm electromagnetic forming method for aluminum material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a warm electromagnetic forming method for an aluminum material, where, in the body to be formed made of aluminum or an aluminum alloy, which can easily form a shape hard to be formed such as a corrugate fin without increasing working cost. <P>SOLUTION: A magnetically permeable heat insulating layer 10a is formed at the inner face or outer face of the cylindrical body 1 to be formed made of aluminum or an aluminum alloy. The body 1 to be formed is heated at 200 to 550°C, thereafter, an electromagnetic forming coil 5 is inserted into the body 1 to be formed and the body 1 to be formed is expanded in diameter by the electromagnetic forming coil 5, or the body 1 to be formed is inserted into the electromagnetic forming coil 5 and the body 1 to be formed is reduced in diameter by the electromagnetic forming coil 5. Then, the electromagnetic forming coil 5 is separated from the body 1 to be formed after the expansion or reduction in diameter. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic molding method for a cylindrical molded body made of aluminum or an aluminum alloy, and in particular, a corrugated fin shape of an LED lamp, and a casing and parts of a motor and a generator, etc. The present invention relates to a warm electromagnetic forming method of an aluminum material that is suitably used when processing and when the aluminum material that is a molded body has low conductivity and high proof stress.

  Recently, a light bulb socket type LED (Light Emitting Diode) lamp is often used. The LED lamp is a lamp that uses a high-intensity LED, and uses an LED as a light source. Therefore, the power consumption is small and the rated life is also long. On the other hand, when an LED is used for a lamp, the amount of heat generated is large, and the LED itself may be vulnerable to heat. In an LED lamp, effective heat dissipation is required.

  FIG. 10 shows a conventional light bulb socket type LED lamp. As shown in FIG. 10, in the LED lamp 9, a heat dissipating part 9c is provided between a base 9a for mounting on a light bulb socket and an illumination part 9b, and the heat dissipating part 9c is made of aluminum or aluminum alloy having high thermal conductivity. It is made up of materials. And as shown in FIG. 10, in order to increase the thermal radiation area from the thermal radiation part 9c, the thermal radiation fin 9d (corrugated fin) is formed in the thermal radiation part 9c (for example, patent document 1 and 2). .

JP 2009-163955 A JP 2009-170114 A

  However, the above-described prior art has the following problems. Conventionally, when processing a shape like a corrugated fin of an LED lamp on an aluminum material, press forming has been performed in the process shown in FIGS. 11 and 12. That is, an annular aluminum plate 6 as shown in FIG. 11A is placed on a bowl-shaped die 7 as shown in FIG. 11B, and the plate 6 is pressed by an upper die 8. The plate 6 is formed into a bowl shape (FIG. 12 (a)), and further press forming is performed a plurality of times to radiate fins 9d (see FIG. 12 (b) and FIG. 12 (c)). 12 (b) is a cross-sectional view, and FIG. 12 (c) is a top view). Accordingly, even when the aluminum material is made of, for example, JIS A 1000 series pure aluminum or JIS A 6063 aluminum alloy having a low deformation resistance, when processing a complicated shape such as a corrugated fin, multi-stage press molding is performed. It is necessary to carry out and shape | mold, and a processing cost increases. In addition, for example, JIS A 6000 series (other than 6063), 3000 series and 7000 series aluminum alloys have high proof stress (high deformation resistance), so that they are processed by press molding as compared with other series aluminum alloys. Sex declines. Therefore, there is a problem that the processing cost of the parts further increases.

  In order to solve this problem, it has been proposed to manufacture a corrugated fin-shaped heat radiation portion by casting. However, it is necessary to keep the thickness of the heat dissipation part as thin as possible because it is used as a part of a small light bulb such as an LED lamp, and the heat dissipation part has a complicated shape like a corrugated fin. If an attempt is made to produce an aluminum material by casting, there is a problem that the productivity is lowered and the product weight is increased, and the production cost and the product cost are increased.

  This invention is made | formed in view of this problem, Comprising: In the to-be-molded body which consists of aluminum or aluminum alloy, the shape which cannot be shape | molded easily, such as a corrugated fin, can be shape | molded easily, without increasing a processing cost. It aims at providing the warm electromagnetic forming method of aluminum material.

  The method for warm electromagnetic forming of an aluminum material according to the present invention includes a step of forming a magnetically permeable heat-insulating layer on the inner surface of a cylindrical molded body made of aluminum or an aluminum alloy, and the molded body at 200 to 550 ° C. A step of heating, a step of inserting an electromagnetic molded coil into the molded body, a step of expanding the molded body with the electromagnetic molded coil, and a step of extracting the electromagnetic molded coil from the molded body. It is characterized by that.

  In another method for warm electromagnetic forming of an aluminum material according to the present invention, a step of forming a magnetically permeable heat-insulating layer on the outer surface of a tubular molded body made of aluminum or an aluminum alloy, and the molded body is formed by 200 to 550. A step of heating to 0 ° C., a step of fitting an electromagnetic molded coil to the molded body, a step of contracting the molded body by the electromagnetic molded coil, and detaching the electromagnetic molded coil from the molded body. And a process.

  In the warm electromagnetic forming method for an aluminum material described above, an annular blank made of aluminum or an aluminum alloy has a flare shape before the step of forming a magnetically permeable heat insulating layer on the inner surface or outer surface of the molded body. It has the process of carrying out a drawing process to a cylinder shape, and it can comprise so that the said blank material may be processed into the said cylindrical to-be-molded body by this drawing process.

  Moreover, you may shape | mold a corrugated fin shape in the said to-be-molded body by the expansion or contraction tube by the said electromagnetic forming coil.

  The above-mentioned to-be-molded body can be heated by, for example, induction heating using a magnetic heating coil. In this case, for example, the magnetic heating coil is arranged coaxially with the electromagnetic forming coil, and the magnetic heating coil and the electromagnetic forming coil are exchanged coaxially.

  The magnetically permeable heat insulation layer is mainly composed of, for example, a shirasu balloon. In this case, for example, the magnetically permeable heat insulating layer is composed of a mixture in which cement is mixed with the shirasu balloon, and the mixture is made into a paste by adding water and applied to the inner surface of the molded body. It is preferable to perform the heating step in a state where the magnetically permeable heat insulating layer contains moisture.

  In the method for warm electromagnetic forming of an aluminum material according to the present invention, tube expansion or contraction is performed with an electromagnetic forming coil in a warm state in which a molded body made of aluminum or an aluminum alloy is heated to 200 to 550 ° C. As a result, it is possible to perform electromagnetic forming of the molded body in a state where the proof stress of the molded body is reduced by heating, and even when forming a shape such as a corrugated fin that is difficult to be molded, the molded body is in a state with good workability. The molded body can be molded, the molding amount of the molded body can be increased as compared with the case of molding at room temperature, and the molding can be easily performed without increasing the processing cost. Further, since the magnetically permeable heat insulating layer is formed on the inner surface or the outer surface of the molded body, it is possible to prevent the electromagnetic molded coil from being damaged by the high-temperature molded body when the molded body is expanded or contracted. it can.

It is typical sectional drawing which shows the warm electromagnetic forming method of the aluminum material which concerns on 1st Embodiment of this invention. (A) thru | or (c) is a figure which shows to the heating process of a to-be-molded body in order of the process in the warm electromagnetic forming method of the aluminum material which concerns on embodiment of this invention. (A) And (b) is a figure which shows the process of expanding a molded body and shape | molding a flare shape in order of the process, and Fig.3 (a) shows the next process of FIG.2 (c). (A) thru | or (c) is a figure which shows the electromagnetic forming coil after a flare-shaped shaping | molding process, a metal mold | die, and a to-be-molded body. It is sectional drawing which shows an example of the electromagnetic forming coil used for the pipe expansion shaping | molding of a to-be-molded body. It is an example which shows the temperature change of a to-be-molded body and a shirasu balloon at the time of applying the mixture of Shirasu balloon and cement to a to-be-molded body. (A) And (b) is a figure which shows the process of shape | molding a to-be-molded body, and shape | molding a flare shape in the order of the process, Fig.7 (a) shows the next process of FIG.2 (c). . (A) thru | or (c) is a figure which shows the electromagnetic forming coil after a flare-shaped shaping | molding process, a metal mold | die, and a to-be-molded body. It is sectional drawing which shows an example of the electromagnetic forming coil used for the reduced tube shaping | molding of a to-be-molded body. It is a side view which shows the conventional light bulb socket type LED lamp. (A) is a top view which shows the aluminum material used as the material of the thermal radiation part of the conventional LED lamp, (b) is a figure which processes an aluminum material by the conventional press work. (A) is a cross-sectional view showing an aluminum material processed by the press work of FIG. 11 (b), (b) is a cross-sectional view showing a corrugated fin processed by further pressing the aluminum material, and (c) is a cross-sectional view. FIG. 13 is a top view of FIG.

  Next, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view illustrating an aluminum material electromagnetic forming method according to the first embodiment of the present invention, and FIGS. 2A to 2C are electromagnetic shapes of the aluminum material according to the first embodiment. FIG. 3A and FIG. 3B are diagrams showing, in the order of the steps, the process of expanding the molded body to form a flare shape in the method. FIG. 3 (a) shows the next step of FIG. 2 (c). FIG. 4A to FIG. 4C are views showing the electromagnetic forming coil, the mold, and the molded body after the flare-shaped forming step. FIG. 5 is a cross-sectional view showing an example of an electromagnetic forming coil.

  In this embodiment, as shown in FIG. 1, a magnetically permeable heat insulating layer 10a is formed on the inner surface of a cylindrical molded body 1 made of aluminum or aluminum alloy (hereinafter, aluminum or aluminum alloy is generically referred to as aluminum material). And, for example, the induction heating coil 2 is inserted into the molded body 1. And the to-be-molded body 1 is heated with the induction heating coil 2 so that it may become a temperature of 200 thru | or 550 degreeC through the magnetic permeability heat insulation layer 10a. Next, as shown by a two-dot chain line in FIG. 1, the heated molded object 1 is lifted, and an electromagnetic molded coil 5 provided above the induction heating coil 2 is inserted. 1 is expanded to process the molded body 1 into a predetermined shape. In this case, the electromagnetic molded coil 5 is protected from the heat of the molded body 1 by the magnetically permeable heat insulating layer 10a. Moreover, since this heat insulation layer 10a is magnetically permeable, the magnetic field from the electromagnetic forming coil 5 acts on the to-be-molded body 1 reliably. In the present embodiment, the mold 4 is disposed outside the electromagnetic forming coil 5, and the molded body 1 is molded into the shape of the mold 4 by pressing the molded body 1 against the mold 4 by expanding the tube. Further, for example, a plate-like tray 3 provided with a hole having a size approximately equal to the inner diameter of the molded body 1 is disposed below the molded body 1, and the molded body 1 is guided by the tray 3 to the induction heating coil 2. Is lifted vertically to the electromagnetic forming coil 5. Moreover, when heating the to-be-molded body 1 with the induction heating coil 2, the induction heating coil 2 is arrange | positioned coaxially with the electromagnetic forming coil 5, for example.

  Examples of the material of the molded body 1 of the present invention include JIS A 1000 series pure aluminum, 2000 series (Al-Cu series alloy), 3000 series (Al-Mn series alloy), 4000 series (Al-Si series). Alloys) Various developments of 5000 series (Al-Mg series alloys), 6000 series (Al-Mg-Si series alloys), and 7000 series (Al-Zn-Mg series alloys, Al-Zn-Mg-Cu series alloys) An aluminum alloy for the material can be used.

  The shape of the molded body 1 is a cylindrical shape, and the induction heating coil 2 and the electromagnetic forming coil are formed in a state of forming a magnetically permeable heat insulating layer 10a on the inner surface in various cylindrical forms such as a cylindrical shape and a rectangular tube shape. However, in the present embodiment, the molded body 1 has a cylindrical shape with an outer diameter of 25 mm or more and a plate thickness of 0.5 to 5.0 mm, for example. Extruded shape. A cylindrical drawing material may be used as the molded body 1.

  The magnetically permeable heat insulating layer 10a is formed on the inner surface of the molded body 1 so as to have a thickness of, for example, 3 to 5 mm. As the material of the magnetically permeable heat insulating layer 10a, the inner surface temperature of the magnetically permeable heat insulating layer 10a can be set to, for example, 150 ° C. or less when the temperature of the molded body 1 is 200 to 550 ° C. Is used. Specifically, for example, a shirasu balloon (for example, JP-A-7-24299) and a microballoon (for example, JP-T-2005-539111) can be used. Specifically, for example, the product name “Taisetsu Balloon” manufactured by Biei Shirachi Kogyo Co., Ltd. can be used. The shirasu balloon is a spherical hollow glassy fine particle obtained by heat-treating a volcanic glassy deposit such as shirasu and having an average particle size of 150 μm or less. When this Shirasu balloon is used as the magnetically permeable heat insulating material 10, water is added to Shirasu balloon particles to form a paste, which is applied to the inner surface of the molded body 1, sprayed, or the inner surface of the molded body 1. And a paste-like shirasu balloon may be poured between the molded body 1 and the receiving member. Moreover, the magnetically permeable heat insulation layer 10a should just have a shirasu balloon as a main component. Specifically, for example, a mixture of shirasu balloon and cement can be used. Even in this case, the mixture of shirasu balloon and cement may be used by adding water to make a paste. FIG. 6 is an example showing temperature changes of the molded body and the shirasu balloon when a mixture of a shirasu balloon and cement is applied to the molded body (application thickness: 3 mm). In FIG. 6, the horizontal axis represents the elapsed time after applying a mixture of shirasu balloon (containing water) and cement to the inner surface of the cylindrical molded body and starting heating using the electromagnetic heating coil. The vertical axis represents the temperature of the inner surface and the outer surface of a molded body that is formed as a laminate by forming a magnetically permeable heat insulating layer. That is, the inner surface in FIG. 6 is the inner surface of the magnetically permeable heat insulating layer (shirasu balloon and cement mixture layer), and the outer surface in FIG. 6 is the outer surface of the molded body. That is. Since the temperature of the outer surface of the molded body reached 460 ° C. 18 seconds after the start of heating, the laminate of the molded body and the magnetically permeable heat insulating layer was separated from the electromagnetic heating coil. As shown in FIG. 6, when a shirasu balloon is applied to the inner surface of the molded body, the temperature of the shirasu balloon layer is 100 ° C. or lower even when the molded body is heated to a high temperature of about 460 ° C. It can be seen that it can be maintained at a low temperature. In the case of using a shirasu balloon as the material of the magnetically permeable heat insulating layer 10a, in order to increase the heat insulating efficiency, the heating process of the molded body 1 is a magnetic permeable structure composed of a mixture of shirasu balloon and cement. It is preferable that the heat insulating layer 10a contains moisture. In this case, the mixture of shirasu balloon and cement contains 95 to 55% by mass of shirasu balloon per total mass of the mixture and 5 to 45% by mass of cement per total mass of the mixture. The mixture may be made into a paste by adding water, and the water content may be adjusted to 3 to 60% by mass based on the total mass of the paste-like mixture containing water. By heating the molded body 1 in a state where the shirasu balloon contains water, the heat insulation efficiency can be improved by utilizing the heat of vaporization when the water vaporizes in addition to the heat insulation of the material itself. The inner surface of the magnetically permeable heat insulating layer (shirasu balloon layer) 10a in a state where the temperature of the molded body 1 is 200 to 550 ° C. by heating the molded body 1 while the shirasu balloon contains moisture. The temperature can be, for example, 100 ° C. or lower. The same applies when a microballoon is used instead of a shirasu balloon.

  The induction heating coil 2 for heating the molded body 1 is formed by winding a conductor wire made of, for example, copper or a copper alloy in a coil shape. 2 Magnetic flux is generated around. Then, an eddy current is generated inside the aluminum material of the molded body 1 by the magnetic flux generated around the coil 2 and is heated by the electric resistance of the aluminum material to heat the molded body 1 (induction heating, induction heating). ) In the present invention, the temperature of the molded body 1 after heating is 200 to 550 ° C.

  The tray 3 is disposed such that the hole positions are along the inner peripheral edge of the molded body 1. Therefore, when the induction heating coil 2 is inserted into the cylindrical shape of the molded body 1, the induction heating coil 2 is also inserted into the hole of the tray 3. Similarly, when the molded body 1 is lifted vertically by the tray 3 and the electromagnetic molded coil 5 is inserted into the cylindrical shape of the molded body 1, the electromagnetic molded coil 5 is also inserted into the hole of the tray 3.

  The mold 4 is a press mold made of, for example, high alloy tool steel (SKD) or high speed tool steel (SKH). As shown in FIGS. 1 and 3, the mold 4 is provided with a hole for inserting the molded body 1, and the molded body 1 is molded according to the shape of the inner surface of the hole. In this embodiment, the shape of the hole is formed in a flare shape so that the inner diameter increases from one end side to the other end side of the mold 4, and the inner surface of the hole has a corrugated fin shape. Corresponding protrusions and groove shapes are provided. Thereby, in this embodiment, the to-be-molded body 1 is shape | molded in the thermal radiation part 9c which has the shape of the corrugated fin 9d of the LED lamp 9 as shown in FIG. In the present invention, the molded body 1 is molded by tube expansion molding so as to correspond to the shape of the inner surface of the hole of the mold 4, but the shape of the hole may be, for example, a prism or a column, It may be formed in a flare shape, or the molded body 1 may be simply expanded into a tube of a predetermined size, or only the flare shape may be molded in the molded body 1.

  As shown in FIG. 5, the electromagnetic forming coil 5 includes a hollow conductor wire 52 having a rectangular cross section covered with, for example, a glass cloth tape 51 on a peripheral surface of a bobbin 50 configured in an axial shape with an insulating resin, for example. However, the bobbin 50 is wound around in a spiral shape to form a coil. In the hollow portion 52a at the center of the conductor wire 52, for example, a coolant flows to cool the conductor wire 52. And this conductor strand 52 is wound so that the surface where the adjacent conductor strand 52 opposes may become parallel. A glass cloth 53 is wound around the outside of the coil so as to have a predetermined thickness. The insulating resin is impregnated in the gap between the glass cloth tape 51, the glass cloth 53, and each component, thereby fixing the insulating layer and the conductor. The electromagnetic forming coil 5 has a predetermined outer diameter by cutting the outer periphery of the glass cloth 53 after impregnation with the resin. The heat resistant temperature of the glass cloth 53 after the resin impregnation is, for example, 120 to 200 ° C.

  Next, operation | movement of the warm electromagnetic forming method of the aluminum material of this embodiment is demonstrated in the order of the process. In the present invention, as shown in FIG. 2 (a), first, cement is mixed with the above-described magnetically permeable heat insulating material 10 such as a shirasu balloon or a microballoon, and a paste formed with water is formed into a cylindrical covering. It apply | coats to the inner surface of the molded object 1, and forms the magnetic permeability heat insulation layer 10a on the inner surface of the to-be-molded body 1 (FIG.2 (b)). At this time, in the mixture, shirasu balloons or microballoons are mixed so as to contain 95 to 55% by mass with respect to the total mass of the mixture, and cement is contained to 5 to 45% by mass with respect to the total mass of the mixture. It is preferable to use it after adding water to the mixture with cement to form a paste and adjusting the water content to 3 to 60% by mass based on the total mass of the paste-like mixture containing water. If the molded body 1 is heated in a state where the magnetically permeable heat insulating material 10 applied to the inner surface of the molded body 1 contains moisture, the heat of vaporization when moisture is vaporized is used in addition to the thermal insulation of the material itself. Thereby, the heat insulation efficiency of the magnetically permeable heat insulation layer 10a can be further improved. Thus, even when the molded body 1 is heated to a high temperature of 200 to 550 ° C. in the subsequent process by forming the magnetically permeable heat insulating layer 10a on the inner surface of the molded body 1, The surface temperature inside the magnetically permeable heat insulation layer 10a can be maintained at a low temperature of, for example, 150 ° C. or less. In the case where the magnetically permeable heat insulating material 10 is applied to the inner surface of the molded body 1 in a state containing moisture, the surface temperature inside the magnetically permeable heat insulating layer 10a can be set to 100 ° C. or less, for example.

  Next, the molded body 1 is placed on the tray 3. At this time, the position of the hole of the tray 3 is set along the inner peripheral edge of the molded body 1. Thereby, if the induction heating coil 2 or the electromagnetic forming coil 5 is inserted into the cylindrical shape of the molded body 1, the induction heating coil 2 or the electromagnetic forming coil 5 is also inserted into the hole of the tray 3. Therefore, the tray 3 can be smoothly lifted from the induction heating coil 2 to the electromagnetic forming coil 5 and heated and expanded without hindering the insertion of the induction heating coil 2 and the electromagnetic forming coil 5. .

  Subsequently, as shown in FIG. 2C, the induction heating coil 2 is inserted into the molded body 1 from the tray 3 side. Then, by applying a high-frequency current to the induction heating coil 2, magnetic lines of force are generated around the coil 2, eddy currents are generated inside the aluminum material of the molded body 1 by the magnetic lines of force, and the electric resistance of the aluminum is applied. The molded body 1 is caused to generate Joule heat. In this invention, it heats until the temperature of the to-be-molded body 1 becomes 200 to 550 degreeC. Since the magnetically permeable heat insulating layer 10a is formed on the inner surface of the molded body 1 as described above, the inner surface of the magnetic permeable heat insulating layer 10a even when the temperature of the molded body 1 is high. The temperature is maintained at a low temperature. When the molded body 1 is heated to a predetermined temperature, the molded body 1 is raised vertically by the tray 3 to separate the molded body 1 from the induction heating coil.

  Next, the molded body 1 is raised right above, and the electromagnetic forming coil 5 shown in FIG. 5 is inserted into the molded body 1 as indicated by a two-dot chain line in FIG. At this time, in the case where the induction heating coil 2 and the electromagnetic forming coil 5 are arranged coaxially, the induction heating coil 2 and the electromagnetic forming coil 5 can be exchanged coaxially with respect to the molded object 1, The replacement process proceeds smoothly. As shown in FIG. 3A, in the present embodiment, a die 4 having a hole having a predetermined shape is disposed outside the electromagnetic forming coil 5, and the electromagnetic forming coil 5 is attached to the molded body 1. By inserting, the to-be-molded body 1 is arrange | positioned between the metal mold | die 4 and the outer peripheral surface of the electromagnetic forming coil 5. FIG. As shown in FIG. 3A, for example, the electromagnetic forming coil 5 is inserted into the molded body 1 until the tray 3 contacts the mold 4. In the present invention, since the magnetically permeable heat-insulating layer 10a is formed on the inner surface of the molded body 1, the heat of the high-temperature molded body 1 is blocked by the magnetically permeable heat-insulating layer 10a, and there is no adverse effect on the electromagnetically formed coil. Less, the resin-impregnated glass cloth on the outer surface of the electromagnetic forming coil 5 can be maintained at a low temperature below its heat resistance temperature. Thereby, it can prevent that the electromagnetic forming coil 5 is damaged by the to-be-molded body 1 of high temperature.

  After the position of the molding object 1 is determined, the electromagnetic molding coil 5 is energized. In the present embodiment, when a pulse voltage is applied to the conductor wire 52 of the electromagnetic forming coil 5 shown in FIG. 5 to cause an instantaneous current to flow through the conducting wire 52, the electric conduction is caused by a change in the electromagnetic field generated around the coil 5. An induced current is generated in the molded object 1 which is a body, and an instantaneous electromagnetic force acts on the molded object 1 in the direction indicated by the arrow 30 in FIG. 5 due to the interaction between the induced current and the electromagnetic field. At this time, since the heat insulating layer 10a is magnetically permeable, the magnetic field of the electromagnetic forming coil surely acts on the object 1 to be molded. Due to the interaction between the induced current and the electromagnetic field, an electromagnetic force in the direction of spreading outwardly acts on the molded body 1. Thereby, the to-be-molded body 1 is pipe-expanded (FIG. 3B). At this time, the magnetically permeable heat insulating layer 10a formed on the inner surface of the molded body 1 also tends to be deformed in accordance with the shape of the molded body 1, but the magnetic permeable heat insulating layer 10a is usually made of an aluminum material. Since the brittleness is high, the layer shape cannot be maintained, and a part of the magnetically permeable heat insulating material 10 is peeled off from the inner surface of the molded body 1. On the other hand, the expanded molded object 1 is pressed against the mold 4 and is molded according to the shape of the outer surface of the mold 4 (in a form close to press molding). Thereby, a corrugated fin shape can be shape | molded in the to-be-molded body 1. FIG.

  After the tube expansion processing of the molded body 1 is completed, the electromagnetic forming coil 5 is pulled out from the molded body 1 as shown in FIG. At this time, if the electromagnetic forming coil 5 is quickly pulled out of the molded body 1, a large amount of heat of the molded body 1 is transmitted from the inner surface of the molded body 1 when the heat insulating material 10 is partially peeled off, and electromagnetic It is possible to prevent the molded coil 5 from being damaged. Thereafter, as shown in FIG. 4 (b), the molded body 1 is pulled out from the mold 4, and the heat insulating material 10 remaining in the molded body 1 is removed by, for example, air blowing or jet cleaning, and the pipe is expanded. The to-be-molded body 1 in which the corrugated fin shape is molded is completed (FIG. 4C).

  According to the warm electromagnetic forming method of the aluminum material of the present embodiment, since the tube 1 is expanded by the electromagnetic forming coil 5 in a state where the object 1 is heated to 200 to 550 ° C., the yield strength of the object 1 is reduced ( Electromagnetic forming can be performed in a state where the deformation resistance is small. Therefore, compared with the case where it processes at normal temperature, the molding amount of the to-be-molded body 1 can be enlarged, the to-be-molded body 1 can be processed with good workability, and the material of the to-be-molded body has a high proof Even when it has, it can be processed easily. That is, even when a difficult-to-mold shape such as a corrugated fin is formed on an aluminum material, the molded body 1 can be processed with good workability, and conventional press molding or casting is performed. Even if it is not, it is possible to easily process a shape that is difficult to be molded, and the processing cost is not increased.

  Further, a magnetically permeable heat insulating layer 10 a is formed on the inner surface of the molded body 1. Thereby, even when the molded body 1 is heated to a high temperature of 200 to 550 ° C., the electromagnetic molded coil 5 can be prevented from being damaged by the high-temperature molded body 1. Furthermore, even after tube expansion molding, if the electromagnetic forming coil 5 is quickly pulled out of the molded body 1, even if the heat insulating material 10 is partially peeled off, the large size of the molded body 1 from the inner surface of the molded body 1. It is possible to prevent the electromagnetic forming coil 5 from being damaged by the amount of heat transmitted. That is, as shown in FIG. 6, the magnetically permeable heat insulating layer 10a used in the present embodiment is magnetically permeable heat insulating layer 10a even when heated to a high temperature of about 460 ° C. The inner surface temperature of the electromagnetic wave can be maintained at a low temperature, and this temperature is lower than the heat resistance temperature (of the resin-impregnated glass cloth) of the electromagnetic forming coil 5 at a position close to the magnetically permeable heat insulating layer 10a. Thereby, it can prevent that the electromagnetic forming coil 5 is damaged by the to-be-molded body 1 of high temperature. Furthermore, in the case of using, for example, a shirasu balloon as the magnetically permeable heat insulating layer, in addition to the heat insulating property of the material itself, by heating the molding 1 in a state where the mixture of the shirasu balloon and cement contains moisture, The heat insulation efficiency can be improved by utilizing the heat of vaporization when moisture is vaporized. The inner surface of the magnetically permeable heat insulating layer (shirasu balloon layer) 10a in a state where the temperature of the molded body 1 is 200 to 550 ° C. by heating the molded body 1 while the shirasu balloon contains moisture. The temperature can be, for example, 100 ° C. or lower.

  In this embodiment, the object 1 is heated by the induction heating coil 2, but the object 1 may not be heated by the induction heating coil 2. If the aluminum material which is the to-be-molded body 1 can be heated to a temperature of 200 to 550 ° C. with the transparent heat insulating layer 10a formed, various heating methods can be employed. However, it is preferable to perform heating by the induction heating coil 2 from the viewpoint of high productivity. In the present embodiment, the magnetically permeable heat insulating layer 10a is formed on the inner surface of the molded body 1. For example, in order to efficiently heat the molded body 1 by the induction heating coil 2, the molded body 1 is not heated from the inner surface side, but a member insertion hole is provided, and an induction heating coil 2 is used to heat the member inserted into the hole, and the molding 1 is heated from the outer surface side. May be. Further, the formation of the magnetically permeable heat insulating layer 10a on the inner surface of the molded body 1 may be performed before the molded body is heated. For example, the induction heating coil 2 is inserted into the molded body 1, In the gap between the inner surface of the molded body 1 and the outer peripheral surface of the induction heating coil 2, the paste-like magnetically permeable heat insulating material 10 (cement mixed with shirasu balloon or microballoon or the like, and water added to form a paste. ) May be formed on the inner surface of the molded body 1 to form the magnetically permeable heat insulating layer 10a.

  Furthermore, in this embodiment, although the to-be-molded body 1 is a cylindrical extrusion shape material, it is not restricted to a cylindrical shape, What is necessary is just the shape which can be expanded by an electromagnetic forming coil, ie, a cylindrical shape. For example, what processed the blank material 6 into the cylindrical to-be-shaped body 1 can be used by drawing-drawing the annular blank board | plate material 6 as shown to Fig.11 (a) by press molding. That is, as shown in FIG. 11 (b), before the step of forming the magnetically permeable heat insulating layer 10 a on the inner surface of the molded body 1, the blank material 6 is placed on the die 7, and the upper die 8 is used. After drawing and processing the blank material 6 into a tubular molded body 1 having a flare shape, heating may be performed to perform electromagnetic tube expansion warmly. As a result, only the corrugated fin shape needs to be formed on the flare-shaped object 1 by electromagnetic tube expansion, so that the processing is easier than in the first embodiment. Moreover, the warm electromagnetic forming method of the aluminum material according to the present invention is not limited to the flare shape and the corrugated fin shape, and can be easily worked on the aluminum material in a warm manner, and is applied when machining various complicated shapes. can do.

  Next, the warm electromagnetic forming method of the aluminum material which concerns on 2nd Embodiment of this invention is demonstrated. FIG. 7A and FIG. 7B are diagrams showing a process of forming a flare shape by reducing the tube shape of the molded body in the second embodiment, in the order of the processes. FIG. The next step of FIG. FIGS. 8A to 8C are views showing the electromagnetic forming coil, the mold, and the molded body after the flare-shaped forming step. FIG. 9 is a cross-sectional view showing an example of an electromagnetic forming coil used for forming a contracted tube of a molded body. In the first embodiment, the molding object 1 is expanded by the electromagnetic force of the electromagnetic molding coil, thereby pressing the outer surface of the molding object 1 against the mold 4 disposed outside the molding object 1. Although the body 1 is molded, in this embodiment, as shown in FIG. 7, the electromagnetic forming coil 5 is fitted to the molded body 1, and the mold 4 is disposed inside the molded body, so that the electromagnetic molding is performed. The molded body 1 is subjected to tube shrinkage by the electromagnetic force of the coil. Thereby, the inner surface of the molded body 1 is pressed against the mold 4, and the molded body 1 is processed according to the shape of the mold 4. In this case, the electromagnetic molded coil 5 is protected from the heat of the molded body 1 by the magnetically permeable heat insulating layer 10a. Moreover, since this heat insulation layer 10a is magnetically permeable, the magnetic field from the electromagnetic forming coil 5 acts on the to-be-molded body 1 reliably. The outer diameter of the molded body 1 is, for example, 25 mm or more as in the first embodiment. In the present embodiment, the magnetically permeable heat insulating layer 10a is formed not on the inner surface of the molded body but on the outer surface. Moreover, when heating the to-be-molded body 1 with the induction heating coil 2, the induction heating coil 2 is arrange | positioned coaxially with the electromagnetic forming coil 5, for example. Other configurations are the same as those of the first embodiment.

  The material of the mold 4 is the same as that of the first embodiment. In the present embodiment, as shown in FIG. 7, the mold 4 is provided in a lump shape that can be inserted into the molded body 1, and its outer diameter increases from one end side to the other end side. It is formed in a flare shape. Further, the outer surface of the mold 4 is provided with a protrusion and a groove shape corresponding to the corrugated fin shape. Thereby, in this embodiment, the to-be-molded body 1 is shape | molded in the thermal radiation part 9c which has the shape of the corrugated fin 9d of the LED lamp 9 as shown in FIG. In the present invention, the molded body 1 is formed by shrink tube forming so as to correspond to the outer surface shape of the mold 4, but the shape of the mold 4 may be, for example, a prism or a column, Only the flare shape may be formed, the molded body 1 may be simply contracted into a cylinder having a predetermined size, or only the flare shape may be molded on the molded body 1.

  As shown in FIG. 9, the electromagnetic forming coil 5 used in the present embodiment is a hollow having a rectangular cross section covered with, for example, a glass cloth tape 51 inside a bobbin 50 configured in a cylindrical shape with an insulating resin, for example. The conductor wire 52 is wound in a spiral shape coaxially with the central axis of the bobbin 50 to form a coil. The conductor strands 52 are wound so that adjacent surfaces of adjacent conductor strands 52 are parallel to each other. A glass cloth 53 is provided inside the coil so as to have a predetermined thickness. The insulating resin is impregnated in the gap between the glass cloth tape 51, the glass cloth 53, and each component, thereby fixing the insulating layer and the conductor. In the present embodiment, the inner diameter of the electromagnetic forming coil 5 is, for example, 30 mm or more.

  Next, operation | movement of the warm electromagnetic forming method of the aluminum material which concerns on this 2nd Embodiment is demonstrated in the order of the process. In addition, in this embodiment, since it is the same as that of 1st Embodiment except the structure and arrangement | positioning of the metal mold | die 4 and the electromagnetic forming coil 5, and the formation position of the magnetic permeability heat insulation layer 10a to the to-be-molded body 1, it is the same. In FIG. 2 (a), the magnetic permeable heat insulating material 10 is applied to the outer surface of the molded body 1 to form the magnetic permeable heat insulating layer 10a, and the steps up to the heating of the molded body 1 are described. Omitted.

  Also in this embodiment, the to-be-molded body 1 is heated until it becomes 200 to 550 degreeC using the induction heating coil 2, for example. A magnetically permeable heat insulating layer 10a made of the same material as that of the first embodiment is formed on the outer surface of the cylindrical molded body 1. In this state, the electromagnetic forming coil 5 shown in FIG. At this time, in the case where the induction heating coil 2 and the electromagnetic forming coil 5 are arranged coaxially, the induction heating coil 2 and the electromagnetic forming coil 5 can be exchanged coaxially with respect to the molded object 1, The replacement process proceeds smoothly. As shown in FIG. 7A, in the present embodiment, the mold 4 having a predetermined shape is disposed not on the outside of the electromagnetic forming coil 5 but on the inside thereof, and the electromagnetic forming coil 5 is formed on the object 1 to be molded. Is fitted between the mold 4 and the inner surface of the electromagnetic forming coil 5. Also in the present embodiment, since the magnetically permeable heat insulating layer 10a is formed on the outer surface of the molded body 1, the heat of the high temperature molded body 1 is blocked by the magnetic permeable heat insulating layer 10a and the electromagnetic molded coil. The resin-impregnated glass cloth on the outer surface of the electromagnetic forming coil 5 can be maintained at a low temperature below its heat resistance temperature. Thereby, it can prevent that the electromagnetic forming coil 5 is damaged by the to-be-molded body 1 of high temperature.

  Next, the electromagnetic forming coil 5 is energized. In the present embodiment, when a pulse voltage is applied to the conductor wire 52 of the electromagnetic forming coil 5 shown in FIG. 9 to cause an instantaneous current to flow through the conducting wire 52, the electric conduction is caused by a change in the electromagnetic field generated around the coil 5. An induced current is generated in the molded object 1 that is a body, and an instantaneous electromagnetic force acts on the molded object 1 in the direction indicated by the arrow 31 in FIG. 9 due to the interaction between the induced current and the electromagnetic field. At this time, since the heat insulating layer 10a is magnetically permeable, the magnetic field of the electromagnetic forming coil surely acts on the object 1 to be molded. Due to the interaction between the induced current and the electromagnetic field, an electromagnetic force is applied to the molded body 1 so as to be compressed inward. Thereby, the to-be-molded body 1 is reduced tube-molded (FIG. 7B). At this time, the magnetically permeable heat insulating layer 10a formed on the inner surface of the molded body 1 also tries to deform according to the shape of the molded body 1. However, since the brittleness is higher than that of the aluminum material, the layer shape is maintained. As a result, part of the magnetically permeable heat insulating material 10 is peeled off from the inner surface of the molded body 1. On the other hand, the compacted molded object 1 is pressed against the mold 4 and molded according to the shape of the outer surface of the mold 4 (in a form close to press molding). Thereby, a corrugated fin shape can be shape | molded in the to-be-molded body 1. FIG.

  When the tube shrinking of the molded body 1 is completed, the electromagnetic forming coil 5 is detached from the molded body 1 as shown in FIG. At this time, if the electromagnetic forming coil 5 is quickly detached from the molded body 1, a large amount of heat of the molded body 1 is transmitted from the outer surface of the molded body 1 when the heat insulating material 10 is partially peeled off. It is possible to prevent the electromagnetic forming coil 5 from being damaged. Thereafter, as shown in FIG. 8 (b), the heat insulating material 10 remaining on the outer peripheral surface of the molded body 1 is removed by, for example, air blowing or jet cleaning, and the tube is contracted to form a corrugated fin shape. The molded object 1 is completed (FIG. 8C).

  Also in the warm electromagnetic forming method of the aluminum material of this embodiment, similarly to the first embodiment, electromagnetic forming can be performed in a state where the yield strength of the molded body 1 is lowered, compared with the case of processing at room temperature. Thus, the molding amount of the molded body can be increased. Therefore, in the reduced tube forming, the molded body 1 can be processed with good workability, and even when the material of the molded body has high proof stress, it can be processed easily. Thereby, even when it is difficult to form a corrugated fin or the like on an aluminum material, the processing cost is not increased. In addition, since the magnetically permeable heat insulating layer 10a is formed on the outer surface of the molded body 1, similarly to the first embodiment, the electromagnetic molded coil 5 is prevented from being damaged by the hot molded body 1. Can do.

  In the present embodiment, various modifications similar to those in the first embodiment can be applied.

(First embodiment)
Next, examples of the effect of the warm electromagnetic forming method of the aluminum material of the present invention will be described below. In this example, first, a pipe (outside diameter of 90 mm, plate thickness of 2.8 mm) made of an aluminum alloy specified in JIS A 6061 (tempering type: T1) is produced by extrusion, and has a length of 200 mm. The aluminum tube was produced by cutting into pieces. And this aluminum pipe | tube was installed in the tray 3, and the induction heating coil 2 was inserted in the inside of a pipe | tube. At this time, the distance between the aluminum tube and the induction heating coil 2 was set to 3 mm over the entire circumference of the tube.

  Next, a magnetically permeable heat insulating layer 10a was formed by pouring water into a mixture of shirasu balloon as a main component into a gap between the aluminum tube and the induction heating coil 2 to form a paste. As the shirasu balloon, one having an average particle size of 30 μm, a bulk density (loose): 0.30, and a bulk density (tap): 0.48 is used. The shirasu balloon is made up of a mixture of shirasu balloon and cement. Cement is mixed so as to contain 5% by mass with respect to 95% by mass per total mass of the mixture, and water is added to the mixture of shirasu balloon and cement to form a paste, and the water content is pasty mixture. It adjusted so that it might become 30 mass% per total mass of.

  The induction heating coil 2 was energized and heated by the induction heating coil 2 until the temperature of the aluminum tube reached 500 ° C.

  Next, the tray 3 is moved, the aluminum tube is extracted from the induction heating coil 2, the tube is lifted vertically, and the magnetically permeable heat insulating layer 10a is formed on the inner surface of the tube, so that it is coaxial with the induction heating coil 2. The arranged electromagnetic forming coil 5 (outer peripheral diameter: 78 mm) was inserted into an aluminum tube. Next, the metal mold | die 4 in which the cylindrical hole (diameter: 100 mm) was formed so that the outer peripheral surface of an aluminum tube might be surrounded was arrange | positioned. At this time, the position of the end portion of the mold 4 was spaced 10 mm from the position of the end portion of the aluminum tube. In this state, the electromagnetic forming coil 5 was energized to perform electromagnetic tube expansion forming on the aluminum tube, and a flange was processed in a section of 10 mm from the end of the tube.

  When the electromagnetic pipe expansion molding was performed on the aluminum pipe by the above steps, a flange having a good shape could be molded at the end of the aluminum pipe.

(Second embodiment)
The second embodiment is an embodiment in which an annular blank material 6 as shown in FIG. 11 (a) is processed into a cylindrical molded body 1 by press molding, and the molded body 1 is subjected to electromagnetic molding. . First, a blank material 6 (an aluminum material having an outer diameter of 145 mm, an inner diameter of 15 mm, and a thickness of 0.5 mm as defined in JIS A 5052) as shown in FIG. The molded object 1 having a maximum outer diameter of 60 mm, a minimum outer diameter of 30 mm, and a height of 40 mm and having a truncated cone shape in a side view was produced.

  And the to-be-molded body 1 was inserted in the hole of the metal mold | die 4, and the metal mold | die 4 was substituted for the tray 3. FIG. In addition, as the metal mold | die 4, what used the groove | channel (depth 8mm, 12 grooves) formed in the inside of the hole was used. And the induction heating coil 2 was inserted in the to-be-molded body 1 like the 1st Example. Next, similarly to the first example, a paste-like shirasu balloon was poured into the gap between the molded body 1 and the induction heating coil 2 to form the magnetically permeable heat insulating layer 10a. The shirasu balloon used is of the same type as the first embodiment.

  And it supplied with electricity to the induction heating coil 2, and it heated with the induction heating coil 2 until the temperature of the to-be-molded body 1 became 450 degreeC.

  Next, the mold 4 is moved, the molded body 1 is extracted from the induction heating coil 2, and the magnetically permeable heat insulating layer 10a is formed on the inner surface of the molded body 1. : 25 mm) was inserted into the molded body 1. In this state, the electromagnetic forming coil 5 is energized, electromagnetic forming is performed on the molded body 1, the outer surface of the molded body 1 is pressed against the mold 4, and FIGS. 12B and 12 ( A corrugated fin shape as shown in c) was processed.

  When the molded body 1 was press-molded from the blank material 6 and electromagnetic tube expansion molding was performed on the molded body 1 through the above steps, a good corrugated fin shape could be molded.

  As described above, the present invention is suitable for a case where a complicated shape is formed on a molded object such as a corrugated fin of an LED lamp. Similarly, the present invention is suitable for molding components that require heat dissipation, such as motor and generator casing components, for example, in the wind power generation field, and that need to be molded into a complicated shape. Can be applied to. Also, for example, in the field of transport equipment, motor and generator casing parts are required to be lightweight in order to reduce vehicle weight, and are also non-magnetic materials so that they are not magnetized by the magnetic field from the motor. It is required to form with. As described above, aluminum or an aluminum alloy is suitable as a material to be used for a portion that is required to be lightweight and non-magnetic. However, the present invention is extremely useful for molding a part made of such an aluminum or aluminum alloy. It is valid.

  1: molding object, 2: heating device (electromagnetic induction coil), 3: tray, 4: mold, 5: electromagnetic forming coil, 6: plate material (blank material), 7: die, 8: upper mold, 9: LED lamp, 9a: base, 9b: illuminating part, 9c: heat radiating part, 9d: heat radiating fin, 10: magnetic permeable heat insulating material, 10a: magnetic permeable heat insulating layer, 50: bobbin, 51: glass cloth tape, 52: Conductor strand, 52a: hollow part, 53: glass cloth

Claims (8)

Forming a magnetically permeable heat insulating layer on the inner surface of a cylindrical molded body made of aluminum or an aluminum alloy;
Heating the molding to 200 to 550 ° C .;
Inserting an electromagnetic forming coil into the molded object;
Expanding the molded body with the electromagnetic forming coil;
Extracting the electromagnetic forming coil from the molded body;
A method for warm electromagnetic forming of an aluminum material, comprising: Forming a magnetically permeable heat-insulating layer on the outer surface of a cylindrical molded body made of aluminum or an aluminum alloy;
Heating the molding to 200 to 550 ° C .;
A step of fitting an electromagnetic forming coil to the object to be molded;
Shrinking the molded body with the electromagnetic forming coil;
Detaching the electromagnetic forming coil from the molded body;
A method for warm electromagnetic forming of an aluminum material, comprising: Before the step of forming the magnetically permeable heat insulating layer on the inner surface or outer surface of the molded body, it has a step of drawing an annular blank made of aluminum or aluminum alloy into a flare-shaped cylinder, The method of warm electromagnetic forming of an aluminum material according to claim 1 or 2, wherein the blank material is processed into the cylindrical object by drawing. The warm electromagnetic forming method for an aluminum material according to any one of claims 1 to 3, wherein a corrugated fin shape is formed on the object by expansion or contraction of the electromagnetic forming coil. The method of warm electromagnetic forming of an aluminum material according to any one of claims 1 to 4, wherein the object to be molded is heated by induction heating using a magnetic heating coil. 6. The aluminum according to claim 5, wherein the magnetic heating coil is coaxially arranged with the electromagnetic forming coil, and the magnetic heating coil and the electromagnetic forming coil are exchanged coaxially with respect to the object to be molded. Warm electromagnetic forming method of material. The method for warm electromagnetic forming of an aluminum material according to any one of claims 1 to 6, wherein the magnetically permeable heat insulating layer is mainly composed of shirasu balloons. The magnetically permeable heat insulating layer is composed of a mixture obtained by mixing cement with the shirasu balloon, applied to the inner surface of the molded body in a paste form by adding water to the mixture,
The method for warm electromagnetic forming of an aluminum material according to claim 7, wherein the heating step of the molded body is performed in a state where the magnetically permeable heat insulating layer contains moisture.

Images