Mold Cooling Device

Abstract

To provide a mold cooling device capable of efficiently cooling a mold and reducing costs.SOLUTION: A mold cooling device is used together with a resin molding device that fills a mold having an annular cavity part with a thermosetting resin and heats the mold and then cools the mold. The mold cooling device is configured by bending a metal tube in a spiral shape, is arranged so that one surface in an axial direction of a central axis of a spiral is in contact with a surface of the mold, and comprises a cooling pipe that cools the mold by heat exchange with a cooling liquid flowing inside.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] This specification discloses a mold cooling system. [Background technology]

[0002] A coil coating forming device that forms an insulating coating on the coil end portion of a stator coil has been proposed that includes a mold having an annular recess on its upper surface into which a thermosetting resin is filled, and a spiral IH coil arranged on the lower surface of the mold (see, for example, Patent Document 1). In this device, the recess of the mold is filled with thermosetting resin, the coil end portion is immersed in the filled thermosetting resin, and a high-frequency alternating current is applied to the IH coil to heat the mold, thereby hardening the thermosetting resin and forming an insulating coating on the coil end portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-129605 A Summary of the Invention [Problem to be solved by the invention]

[0004] When molding using thermosetting resins on a production line, the mold needs to be repeatedly heated and cooled in order to be used repeatedly, and a mold cooling device using, for example, a copper heat sink can be considered. However, over time, contact marks (dents) may appear on the heat sink due to contact with the mold, and the adhesion between the mating surfaces of the mold and the heat sink may deteriorate, resulting in the formation of an air layer, which may reduce the cooling efficiency. In addition, the use of a dedicated heat sink leads to increased costs.

[0005] The primary object of the mold cooling device disclosed herein is to provide a mold cooling device that can efficiently cool a mold while reducing costs. [Means for solving the problem]

[0006] The mold cooling device of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The mold cooling device of the present disclosure is A mold cooling device that is used together with a resin molding device that fills a mold having an annular cavity with a thermosetting resin and heats the mold, and that cools the mold, The gist of the invention is that the cooling pipe is configured by bending a metal tube into a spiral shape and is arranged so that one surface in the axial direction of the central axis of the spiral is in contact with the surface of the mold, and the cooling pipe cools the mold by heat exchange with a cooling liquid flowing inside.

[0008] In the mold cooling device of the present disclosure, a metal pipe is bent into a spiral shape, and one surface in the axial direction of the central axis of the spiral is arranged to contact the surface of the mold, and the cooling pipe cools the mold by heat exchange with the cooling liquid flowing inside. When a heat sink is used as the mold cooling device, contact marks are generated due to contact between the mold and the heat sink over time, and the adhesion of the mating surfaces of the mold and the heat sink deteriorates, which may result in a decrease in cooling efficiency due to the presence of an air layer. In contrast, in the mold cooling device of the present disclosure, the elastic effect of the spiral shape of the cooling pipe can increase the adhesion with the mold, thereby improving the cooling efficiency. In addition, the adhesion between the cooling pipe and the mold can be maintained even with long-term use, so the decrease in cooling efficiency can be suppressed. Furthermore, since a general-purpose metal pipe can be used as the cooling pipe, costs can be reduced compared to those using a dedicated heat sink. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a stator for an electric motor. [Diagram 2] 5 is an explanatory diagram showing an insulating film forming step of forming an insulating film on a coil end portion of a stator coil. FIG. [Diagram 3]FIG. 2 is a cross-sectional perspective view of a mold used in an insulating coating forming step. [Figure 4] 5 is an explanatory diagram showing a state in which a coil end portion of a stator coil is immersed in a thermosetting resin filled in a mold. FIG. [Diagram 5] FIG. 2 is a front view of a mold cooling device used in the mold cooling process. [Figure 6] FIG. 2 is a cross-sectional perspective view of a mold and a mold cooling device. [Figure 7] FIG. 10 is an explanatory diagram showing the cooling of a mold using a mold cooling device of a comparative example. [Figure 8] FIG. 2 is an explanatory diagram showing the state of die cooling using the die cooling device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0011] Fig. 1 is a schematic diagram of a stator for an electric motor. The stator 10 for an electric motor is combined with a rotor to form a three-phase AC generator motor, and is used as a motor or generator for driving an electric vehicle, a hybrid vehicle, etc. As shown in Fig. 1, the stator 10 includes a stator core 12 and a plurality of stator coils 15 (U-phase coil, V-phase coil, and W-phase coil).

[0012] The stator core 12 is constructed by stacking multiple non-oriented electromagnetic steel sheets formed into a circular ring shape, for example by press working, and has multiple teeth that protrude radially inward at predetermined intervals in the circumferential direction so that multiple slots are formed on the inner side.

[0013] Each of the stator coils 15 is formed by electrically joining a plurality of segment conductors 14. The segment conductor 14 is a substantially U-shaped conductor having a rectangular cross section made of a highly conductive metal such as copper and having an insulating coating made of enamel resin or the like formed on its surface. The insulating coating is removed from the end 14e of each of the segment conductors 14, since the end 14e is to be joined to the end 14e of another segment conductor 14. One end 14e of each of the segment conductors 14 is inserted from one end side to the other end side in the axial direction into a corresponding slot of the stator core 12, and the other end 14e is inserted from one end side to the other end side in the axial direction into another slot spaced circumferentially from the corresponding slot, and the end 14e of each of the segment conductors 14 protruding outward from the other end side in the axial direction of the slot is welded and joined to the end 14e of the corresponding other segment conductor 14, thereby forming the plurality of stator coils 15, i.e., the U-phase coil, the V-phase coil, and the W-phase coil.

[0014] An insulating film is formed on the coil end portion 15e of the stator coil 15 to insulate the welded portion. Fig. 2 is an explanatory diagram showing an insulating film forming process in which an insulating film is formed on the coil end portion of the stator coil using a die 20 on a production line. As shown in Fig. 3, the die 20 has an annular cavity 22 formed on its upper surface. The annular cavity 22 has a diameter corresponding to the diameter of the coil end portion 15e and a depth corresponding to the amount of protrusion of the coil end portion 15e.

[0015] In the insulating film forming process, first, a resin filling process is performed in which a thermosetting resin is filled into the cavity 22 of the mold 20 (S100). Next, the coil end portion 15e of the stator coil 15 is immersed in the cavity 22 filled with the thermosetting resin (S110). Then, a heating process is performed in which the mold 20 is heated and the thermosetting resin is hardened (S120). The heating process is a process in which the coil end portion 15e of the coil 15 is molded with the thermosetting resin by the mold heating device 25. As shown in FIG. 4, the mold heating device 25 is disposed on the lower surface of the mold 20 and has an IH coil. The IH coil is a flat and spiral coil, and when a high-frequency alternating current is applied, an eddy current is generated in the mold 20 by magnetic lines (electric field), and the mold 20 is heated by Joule heat.

[0016] After the coil end portion 15e is molded with a thermosetting resin by the heating step, the coil end portion 15e is released from the mold 20 (S130), and the mold 20 is cooled by the mold cooling device 30 in a cooling step (S140). The cooling step is a step for returning the temperature of the mold 20 to a temperature suitable for filling with a thermosetting resin after the heating step is completed and before the next resin filling step when the mold 20 is used repeatedly in a production line. FIG. 5 is a front view of the mold cooling device used in the cooling step, and FIG. 6 is a cross-sectional perspective view of the mold and the mold cooling device. As shown in the figure, the mold cooling device 30 includes a cooling pipe 31 arranged so as to contact the lower surface of the mold 20, and a support member 32 that supports the cooling pipe 31 from the opposite side to the mold 20. The cooling pipe 31 is a metal pipe that is flexible and has excellent thermal conductivity, such as copper, aluminum, a copper alloy, or an aluminum alloy, and is configured as a metal pipe that is bent in a spiral shape on the same plane. This cooling pipe 31 is arranged so that one surface (upper surface) in the axial direction of the central axis of the spiral is in contact with the lower surface of the mold 20, and a cooling liquid (cooling water) is supplied from one open end of the cooling pipe 31 while in contact with the mold 20, thereby cooling the mold 20 by heat exchange with the cooling water flowing inside. The support member 32 is a flat elastic body made of heat-resistant resin such as heat-resistant rubber, and supports the cooling pipe 31 from the other surface (lower surface) in the axial direction of the central axis so that the cooling pipe 31 is pressed against the mold 20 by elastic force.

[0017] FIG. 7 is an explanatory diagram showing the cooling of a mold using a mold cooling device of a comparative example, and FIG. 8 is an explanatory diagram showing the cooling of a mold using a mold cooling device of this embodiment. As shown in FIG. 7, the mold cooling device 20B of the comparative example is provided with a copper heat sink 31B in which a water channel through which cooling water flows is formed and whose upper surface (mating surface) is machined to conform to the lower surface of the mold 20. In the mold cooling device 30B of the comparative example, the mating surface of the heat sink 31B is brought into contact with the lower surface of the mold 20 and cooling water is supplied to the water channel of the heat sink 31B, so that the heat of the mold 20 is transferred to the heat sink 31B to cool the mold 20. Since copper, which has high thermal conductivity but is flexible, is used as the material of the heat sink 31B, contact marks (dents) with the mold 20 may occur on the mating surface of the heat sink 31B due to long-term use, and the mold 20 may ride on the contact marks and deteriorate the adhesion with the heat sink 31B. In this case, the cooling efficiency is significantly reduced due to the air layer interposed between the mold 20 and the heat sink 31B.

[0018] In contrast, in the mold cooling device 30 of this embodiment, as shown in Fig. 8, the cooling pipe 31 is formed by bending a metal pipe having flexibility and excellent thermal conductivity into a spiral shape, and the elasticity of the spiral shape of the cooling pipe 31 can increase the adhesion with the mold 20, thereby improving the cooling efficiency. In addition, since the adhesion can be maintained even with aging, the decrease in cooling efficiency due to aging can be suppressed. Furthermore, since a general-purpose metal pipe such as a copper pipe or an aluminum pipe can be used as the cooling pipe 31, the cost can be reduced compared to the comparative example in which a dedicated heat sink is used.

[0019] Furthermore, in the mold cooling device 30 of this embodiment, the support member 32 that supports the cooling pipe 31 is made of a rubber elastic body. Therefore, even if the mold 30 is tilted or has some unevenness, as shown in FIG. 8, the elastic action of the spiral shape of the cooling pipe 31 and the elastic action of the material of the support member 32 can adequately bring the cooling pipe 31 into close contact with the mold 20, thereby improving cooling efficiency.

[0020] In the above-described embodiment, the support member 30 is made of a rubber elastic material, but this is not limited to this. For example, the cooling pipe 31 may be supported by being pressed against the mold 20 by a plurality of springs.

[0021] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0022] The present invention can be used in the mold cooling device manufacturing industry. [Explanation of symbols]

[0023] 10 stator, 12 stator core, 14 segment conductor, 14e end portion, 15 stator coil, 15e coil end portion, 20 mold, 21 cavity, 25 mold heating device, 30 mold cooling device, 31 cooling tube, 32 support member.

Claims

1. A mold cooling device that is used together with a resin molding device that fills a mold having an annular cavity with a thermosetting resin and heats the mold, and that cools the mold, A cooling pipe is provided in which a metal pipe is bent in a spiral shape and a cooling liquid flows therethrough, the die is cooled by bringing one surface of the cooling pipe in the central axis direction into contact with the surface of the die and flowing a cooling liquid through the cooling pipe; Mold cooling device.

2. The mold cooling device according to claim 1, a support member formed of an elastic body and supporting the cooling pipe from the other surface side in the central axis direction; Mold cooling device.

3. The mold cooling device according to claim 2, The elastic body is rubber. Mold cooling device.

4. The mold cooling device according to any one of claims 1 to 3, The metal tube is made of copper, aluminum, a copper alloy, or an aluminum alloy. Mold cooling device.

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