JP2009170538A - Ignition device, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition device that can prevent performance deterioration due to rust etc., by preventing water etc., from sticking on a core surface, and can prevent the occurrence of crack of an insulating resin injected into a coil case at a core periphery, and to provided a manufacturing method thereof. <P>SOLUTION: The ignition device 1 including a case 3 having a core storage cylinder 32 inside, a core 4 fitted in the core storage cylinder 32 while projected from the core storage cylinder 32, an ignition coil 2 fitted in the core storage cylinder 32 so that the core storage cylinder 32 projects from an end surface thereof, and the resin 9 injected into the case 3 to be cured, is provided with a resin-made annular body 5 forming a first gap 71 between the annular body 5 and a top-portion peripheral edge 321 of the core storage cylinder 32, and the resin 9 is made to flow in the top-portion peripheral edge of the core storage cylinder 32. Further, an ignition coil 2 is provided with a plate shape pedestal portion 215 along the peripheral edge of the annular body 5, and the resin 9 is supplied from a second gap 72 formed between adjacent pedestal portions 215 to the first gap 71. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ignition device and a method for manufacturing the same, and in particular, prevents moisture from adhering to the core surface to prevent performance deterioration due to rust and the like, and insulation injected around the core and inside the coil case. TECHNICAL FIELD OF THE INVENTION

  With higher performance of engines, higher performance has been demanded for ignition devices used therefor. Conventionally, it is known that when an ignition coil is accommodated in an insulator case and resin is injected into the case and cured, the pressure resistance of the ignition coil is improved and the reliability of the ignition device is increased.

  For example, in Patent Document 1, a core storage cylinder in which a rod-shaped core is insert-molded from the outside is formed so as to protrude into the case, and a primary coil bobbin and a secondary coil bobbin are fitted to the outer periphery of the core storage cylinder. In the engine ignition device in which insulating resin is injected into the coil case with one surface open and the whole is integrally molded, a spacer for preventing cracking is provided between the core housing cylinder and the secondary coil bobbin. It is described that the spacer itself is buried under the liquid surface of the mold resin and the mold resin is removed to prevent cracks from occurring.

In Patent Document 2, an ignition device wound around a bobbin is housed in an insulating case, and the insulating case is inserted through the central hole of the bobbin so that a resin is injected into the insulating case and cured. In an engine ignition device, a synthetic resin collar is attached at a position corresponding to the resin level on the outer periphery of the iron core, and cracks occur around the iron core due to the difference in thermal expansion coefficient between the iron core and the synthetic resin. It is described to prevent the occurrence of.
JP 2000-182862 A Japanese Utility Model Publication 1-28668

  As described above, in the ignition device for an internal combustion engine, moisture, mud, or the like is applied to the contact portion between the core and the insulating resin injected into the coil case and the contact portion between the core and the core housing cylinder. Attempts have been made to prevent adhesion and prevent performance degradation due to rust, etc. In the configuration of Patent Document 1, for example, if the end of the spacer protrudes from the liquid surface of the resin, the core and spacer Moisture and mud enter the gaps between them, which may rust the core surface and degrade the performance of the ignition device. Moreover, in the structure of patent document 2, since resin does not penetrate | invade between an iron core and a color | collar, the same problem may arise.

  The present invention has been made in view of such problems, and prevents adhesion of moisture and the like to the core surface, prevents performance deterioration due to rust and the like, and is injected around the core and inside the coil case. An object of the present invention is to provide an ignition device capable of preventing the occurrence of cracks in an insulating resin, and a method for manufacturing the same.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a case having an open surface and a core storage tube projecting toward the open surface, and the core storage tube A core fitted inside the core storage cylinder so as to protrude from the top of the core, and an ignition coil fitted outside the core storage cylinder so that the top of the core storage cylinder protrudes from an end surface thereof, An ignition device for an internal combustion engine comprising a resin that is injected into the case and cured, and is made of a resin that is provided so as to surround the periphery of the top so as to form a gap with the periphery of the top of the core housing cylinder. An annular body is provided.

  Moreover, invention of Claim 2 among this invention is the ignition device of Claim 1, Comprising: The said annular body is mounted, and the said ignition coil is intermittently along the periphery of the said annular body. Suppose that it has the several plate-shaped base part protruded.

  Moreover, invention of Claim 3 among this invention is an ignition device of Claim 2, Comprising: The said ignition coil is a primary bobbin by which a primary coil is wound, The said primary bobbin is accommodated in the inside. And a secondary bobbin around which the secondary coil is wound, and the pedestal portion protrudes from the outer peripheral side of the flange portion of the primary bobbin.

  According to a fourth aspect of the present invention, there is provided the internal combustion engine ignition device according to the first aspect, wherein the annular body is a plate-shaped side surface provided in parallel with the side surface of the core housing cylinder. It shall have.

  Moreover, invention of Claim 5 is an ignition device of Claim 1, Comprising: The primary terminal to which the signal wire | line of an ignition unit is connected, and the insulator provided in the said primary terminal are provided. The annular body is integrated with the insulator.

  The invention according to claim 6 of the present invention is the ignition device according to claim 1, wherein the annular body has a plurality of protrusions formed intermittently on the inner side surface along the inner side surface. It has a portion, and the protrusion is fitted to the side surface of the core or the core storage cylinder with the core being in contact with the side surface of the core or the core storage cylinder.

  According to a seventh aspect of the present invention, the invention according to claim 7 projects from a case having an open surface and a core storage tube projecting toward the open surface, and a top portion of the core storage tube. A core that is fitted inside the core housing cylinder, an ignition coil that is fitted to the outside of the core housing cylinder so that a top portion of the core housing cylinder projects from an end surface thereof, and a top portion of the core housing cylinder A method for manufacturing an ignition device for an internal combustion engine comprising a resin annular body provided so as to surround the periphery of the top so as to form a gap with the periphery, and the ignition coil is fitted into the core housing cylinder And a step of providing the annular body on the periphery of the top of the core housing cylinder, and a step of injecting a resin into the case and curing the resin.

  According to the present invention, moisture and the like are prevented from adhering to the contact portion between the core and the insulating resin injected into the coil case (insulating case) and the contact portion between the core and the core housing cylinder, and rust or the like. Performance degradation can be prevented. Further, it is possible to prevent cracks from occurring in the insulating resin injected around the core and inside the coil case.

Hereinafter, embodiments will be described with reference to the drawings.
FIG. 1 shows a perspective view of an internal combustion engine ignition device 1 described as an embodiment. FIG. 2 shows a state where an annular body 5 described later is removed from the ignition device 1 shown in FIG. FIG. 3 shows an exploded perspective view of the ignition device 1.

  As shown in FIGS. 1 to 3, the ignition device 1 includes a resin-made primary bobbin 21 around which a primary coil 212 is wound, a primary bobbin 21 fitted therein, and a secondary coil 222 wound around it. An ignition coil 2 having a secondary bobbin 22 made of resin, a resin insulating case 3 having a substantially outer shape having an open surface 31 and housing an ignition coil 2 therein, and a magnetic plate such as iron are laminated. A substantially horseshoe-shaped (U-shaped) core 4, a resin-made annular body 5, and an ignition unit 6 mounted in the insulating case 3 and mounted with circuit elements constituting an ignition circuit. It consists of

  In the following description, for convenience of description, the direction from the bottom surface 30 of the insulating case 3 to the open surface 31 is upward (in the direction of arrow X in FIGS. 1 and 2), and the open surface 31 of the insulating case 3 is bottom surface. A direction toward 30 is referred to as a downward direction (a direction opposite to the arrow X in FIGS. 1 and 2).

  At the substantially central position of the bottom surface 30 of the insulating case 3 inside the insulating case 3, it extends upward from the bottom surface 30 of the insulating case 3 toward the open surface 31, and its top peripheral edge 321 is substantially at the same level as the open surface 31. A core housing cylinder 32 having a substantially rectangular cylindrical shape is provided. The internal space of the core storage cylinder 32 penetrates the bottom surface 30 of the insulating case 3.

  The core 4 is integrated with the insulating case 3 by insert molding. About half of the core 4 is fitted in the core housing cylinder 32, and the other part of the core 4 exposed from the bottom surface 30 of the insulating case 3 is U-shaped near the bottom surface 30 of the insulating case 3. After bending, it extends upward along the surface of the insulating case 3. In the present embodiment, glass-filled polybutylene terephthalate (PBT) having good adhesion to the thermosetting epoxy resin is used as the material of the insulating case 3.

  Mounting holes 33 and 34 for mounting the ignition device 1 to an engine block (not shown) are provided at predetermined positions of the core 4 outside the insulating case 3. The two end surfaces 41 and 42 of the core 4 are both formed in an arc shape in side view following the outer peripheral shape of the flywheel 81 to which the ignition device 1 is attached.

  The top peripheral edge 321 of the core housing cylinder 32 protrudes slightly upward from the upper end surface of the primary bobbin 21 or the secondary bobbin 22 of the ignition coil 2. Further, the end surface 42 on the open surface 31 side of the core 4 protrudes slightly above the top of the core housing cylinder 32.

  Near the top of the core storage cylinder 32, one end thereof is sandwiched between the core 4 and the core storage cylinder 32, and an earth terminal 43 having a substantially “U” -shaped terminal surface is provided at the other end. Yes.

  FIG. 4 shows a perspective view of the insulating case 3 viewed from the direction in which the earth terminal 43 is provided. As shown in the figure, a cut surface 322 is formed on the side surface of the core storage cylinder 32 around the ground terminal 43 by cutting the side surface into a substantially rectangular shape.

  3 and 4, the earth terminal 43 is depicted as extending vertically upward, but when the ignition device 1 is assembled, the earth terminal 43 is near the base as shown in FIG. 1 or 2. It is bent from the vicinity of the lower edge of the cut surface 322 to the outer peripheral side of the insulating case 3 and coupled to a projection 2261 of a connecting plate 226 described later.

  As shown in FIGS. 1 to 3, a primary terminal 35 insert-molded in the insulating case 3 is provided on the side surface near the stern equivalent position of the insulating case 3 so as to penetrate inside and outside of the insulating case 3. The primary terminal 35 is electrically connected to the high-voltage side terminal of the primary coil 212.

  On the other hand, a substantially cylindrical socket 36 is provided near the bow equivalent position of the insulating case 3. A high voltage terminal 37 is provided in the socket 36. A high tension cord (not shown) led from the outside of the insulating case 3 is electrically connected to the high voltage terminal 37.

  The primary bobbin 21 around which the primary coil 212 is wound and the secondary bobbin 22 around which the secondary coil 222 is wound have hollow portions 213 and 223 that are both substantially rectangular cylinders and penetrate in a substantially rectangular parallelepiped shape. ing.

  The primary bobbin 21 has a drum 211 around which the primary coil 212 is wound, and flanges 2111 and 2112 provided at both ends of the drum 211. The secondary bobbin 22 includes a drum 221 around which the secondary coil 222 is wound and flanges 2211 and 2122 provided at both ends of the drum 221. As shown in FIG. 3, the drum 221 of the secondary bobbin 22 is divided into a plurality of sections.

  A stopper or a plate (secondary plate 225, connection to be described later) when the primary bobbin 21 is fitted to the secondary bobbin 22 are provided at predetermined positions on the peripheral edge of the flange 2111 of the primary bobbin 21 and the flange 2211 of the secondary bobbin 22. A locking portion for fixing the plate 226 and the primary plate 227) is provided.

  A flat pedestal portion 215 that is intermittently formed along the periphery of the annular body 5 and protrudes upward is provided at the periphery of the opening of the flange portion 2111 located on the open surface 31 side of the primary bobbin 21. ing.

  A secondary plate 225, a connection plate 226, and a primary plate 227 are provided on the flange portion 2211 located on the open surface 31 side of the secondary bobbin 22.

  Among these, the secondary plate 225 is formed with a star-shaped connection portion 2251 for connection to the high voltage terminal 37. A terminal on the high voltage side of the secondary coil 222 is electrically connected to the connection portion 2251.

  The connecting plate 226 has a protrusion 2261 that is electrically connected to the terminal surface of the bent ground terminal 43. The connection plate 226 is electrically connected to the low voltage side terminal of the primary coil 212, the wiring for supplying a signal from the ignition unit 6, the low voltage side terminal of the secondary coil 222, and a ground line (not shown). .

  A primary terminal 35 is electrically connected to the primary plate 227 through a hole 2271 formed at a predetermined position thereof. The primary plate 227 is connected to the primary coil 212 and signal lines from the ignition unit 6. In addition, when the primary plate 227 and the primary terminal 35 are electrically connected, an ignition instruction signal input from the primary terminal 35 is input to the ignition unit 6 and a high voltage is generated on the secondary plate 225 side.

  As shown in FIGS. 1 and 3, the annular body 5 has a plate-like side surface provided in parallel with the side surface of the core housing cylinder 32 (or the side surface of the core 4), and the whole is a flat shape having a substantially rectangular shape in plan view. (In this embodiment, the thickness is about 5 mm). On the inner side surface of the annular body 5, a plurality of protrusions 51 made of ridges extending in the axial direction of the annular body 5 are formed at intervals. Each protrusion 51 is formed intermittently along the inner periphery of the annular body 5. In the present embodiment, the height of the top of each protrusion 51 is about 1 mm.

  In this embodiment, a thermosetting epoxy resin is used as the insulating resin 9 injected into the insulating case 3, and polybutylene terephthalate (PBT) is used as the material of the annular body 5, whereby the resin 9 and the annular body are used. Adhesion between the two is enhanced.

  The shape of the annular body 5 is not necessarily limited to the above shape. The annular body 5 may not be a member closed in an annular shape, and may be a member partially opened. The annular body 5 may be a member having a shape surrounding at least the top peripheral edge 321 of the core housing cylinder 32. The protrusion 51 is not limited to the shape as described above, and may be a shape that forms a gap with the periphery of the top of the core storage cylinder 32.

  The annular body 5 may be configured to extend from the insulator 351 of the primary terminal 35, and the primary terminal 35 may be attached to the extended annular body 5. By doing in this way, assembly property can be improved. Furthermore, in this case, the primary terminal 35 may be insert-molded into the extended annular body 5. According to this, the assembling property can be further improved.

  5A and 6A are plan views of the ignition device 1. FIG. 5B and 6B show side views of the ignition device 1 cut out from a part of the side surface. 5A and 5B show a state where the annular body 5 is attached, and FIGS. 6A and 6B show a state where the annular body is removed.

  As shown in FIG. 5A, the annular body 5 is in contact with the side surface of the core housing cylinder 32 at the top of the protrusion 51. As a result, a gap (hereinafter referred to as a first gap) having a predetermined thickness (about 1 mm in this embodiment) is formed between the core storage cylinder 32 and the core 4 (or the core storage cylinder 32) along the outer periphery of the core storage cylinder 32. (Referred to as a gap 71).

  As shown in FIG. 5B, the lower peripheral edge of the annular body 5 is in contact with the top ends of the one or more pedestals 215. In addition, since the base part 215 is intermittently provided along the periphery of the annular body 5 on the insulating case 3 side, the lower peripheral edge and the primary side of the annular body 5 are in a state where the annular body 5 is in contact with the base part 215. A gap (hereinafter referred to as a second gap 72) is formed between the bobbin 21 and the flange portion 2111. The second gap 72 communicates with the first gap 71. As will be described later, the resin 9 is supplied to the first gap 71 through the second gap 72. Note that due to the presence of the cut surface 322 shown in FIG. 4, relatively large gaps (the first gap 71 and the second gap 72) are formed around the cut surface 322.

  As shown in FIG. 5B or FIG. 6B, the upper peripheral edge of the annular body 5 is slightly below the lowermost point (position closest to the insulating case 3) of the end surface 41 of the core 4 so as not to contact the flywheel 81. Is located.

  Next, a method for manufacturing the ignition device 1 using the member having the configuration described above will be described. It is assumed that the core 4, the ground terminal 43, the primary terminal 35, and the high voltage terminal 37 are already integrated and provided in the insulating case 3. Further, it is assumed that the secondary plate 225, the connection plate 226, and the primary plate 227 are already attached to the secondary coil 222.

  When manufacturing the ignition device 1, first, the ignition coil 2 is stored in the insulating case 3. Next, the ground terminal 43 is bent so that the terminal surface overlaps the protrusion 2261 of the connecting plate 226. Next, each terminal of the primary coil 212 and the secondary coil 222, the secondary plate 225, the connecting plate 226, the primary plate 227, the primary terminal 35, the high voltage terminal 37, and the lead connected to the ignition unit 6 are brazed ( Lead-free solder, etc.), fusing, screwing, etc., each connected to a predetermined position.

  Next, the annular body 5 is inserted and fitted from the top side of the core housing cylinder 32 until it comes into contact with the top of at least one of the pedestal parts 215, and a thermosetting resin (for example, epoxy resin) is inserted from the opening surface of the insulating case 3. A resin 9 such as is injected. The injected resin 9 flows into the gap between the ignition coil 2 and the ignition unit 6 and hardens. In the vicinity of the annular body 5, the resin 9 flows into the first gap 71 through the second gap 72, and the top peripheral edge 321 of the core housing cylinder 32 is also enclosed by the resin 9.

  Here, since the resinous annular body 5 is provided so as to surround the top peripheral edge 321 so as to form a gap (first gap 71) between the core storage cylinder 32 and the top peripheral edge 321, the insulating case 3 is provided. When the resin 9 is injected into the resin, the resin 9 is guided into the gap (first gap 71) formed by the annular body 5, and the resin 9 wraps around the top peripheral edge 321 of the core storage cylinder 32. A gap formed between the core 4 and the core 4 is sealed with the resin 9. For this reason, the intrusion of moisture from the gap formed between the top peripheral edge 321 of the core storage cylinder 32 and the core 4 is prevented, and the contact portion between the core 4 and the resin 9 (for example, the cut surface 322 in FIG. 4), and It is possible to prevent moisture and the like from adhering to a contact portion between the core 4 and the core storage tube 32 (for example, a contact portion between the top peripheral edge 321 of the core storage tube 32 and the core 4) and prevent performance deterioration due to rust or the like.

  Further, since the pedestal portion 215 is intermittently provided along the peripheral edge of the annular body 5, the resin 9 is reliably transferred to the first gap 71 through the gap (second gap 72) between the adjacent pedestal portions 215. Can be supplied.

  In addition, since the resin 9 that has entered the first gap 71 and has hardened directly contacts the surface of the core 4, there is a possibility that cracks may occur in this portion of the resin due to a difference in thermal expansion coefficient between the two. However, even if a crack is generated, the growth of the crack is blocked because the annular body 5 exists. That is, the annular body 5 also plays a role of preventing the growth of cracks generated in the first gap 71, thereby reliably preventing performance deterioration of the ignition device 1.

  By the way, the ignition device 1 can take various forms other than the above-described configuration according to the purpose of use and the use situation. FIG. 7A (plan view) and FIG. 7B (partially cutaway side view) show another example of the ignition device 1. In the ignition device 1 shown in these drawings, the core housing cylinder 32 is configured separately from the insulating case 3, and the core housing cylinder 32 also plays a role as the primary bobbin 21 of the ignition coil 2 in the above-described embodiment. . The primary terminal 35 is provided with a cylindrical insulator 351 that is fitted to the primary terminal 35 and has a disc-shaped end surface 352 having a slightly larger outer shape than other portions. As shown in FIG. 7A, the annular body 5 has a substantially square planar shape. In the ignition device 1, a material that is not easily hydrolyzed (for example, nylon resin) is used as a material for the core housing cylinder 32, and hydrolysis of the core housing cylinder 32 after the resin 9 is thermally cured is prevented.

  Here, for example, when a nylon resin is used as the material of the core housing cylinder 32 and a thermosetting epoxy resin is used as the material of the resin 9, the nylon resin does not necessarily have good adhesion with the thermosetting epoxy resin. Therefore, the resin 9 is peeled off from the core housing cylinder 32 due to deterioration over time, and the peeled portion may be enlarged depending on the situation. However, even when such peeling occurs, the annular body 5 is placed so as to surround the periphery of the top so that a gap is formed between the periphery of the top of the core storage cylinder 32, so Can be reliably dammed up.

  8A (plan view) and FIG. 8B (partially cutaway side view) are further modifications of the ignition device 1 shown in FIGS. 7A and 7B. In the ignition device 1, the annular body 5 and the insulator 351 are integrated. FIG. 8C is a perspective view of a member (hereinafter denoted by reference numeral 81) in which the annular body 5 and the insulator 351 are integrated. As shown in the figure, the member 81 includes an annular body 5, an insulator 351, and a rod-shaped connecting member 811 having a substantially rectangular cross section for connecting them, and the annular body 5 is formed from the insulator 351 of the primary terminal 35. The connecting member 811 extends. Thus, if the annular body 5 and the insulator 351 are configured integrally, the manufacturing process of the annular body 5 (or the insulator 351) can be simplified. Moreover, the assembly | attachment property of the annular body 5 (or insulator 351) can be improved.

  The above description of the embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

It is a perspective view of the ignition device 1 in the state where the annular body 5 is attached. It is a perspective view of ignition device 1 in the state where annular body 5 was removed. 2 is an exploded perspective view illustrating the structure of the ignition device 1. FIG. It is the perspective view which looked at the insulation case 3 from the direction in which the earth terminal 43 is provided. It is a top view of the ignition device 1 of the state which attached the annular body 5. FIG. It is a side view of the ignition device 1 of the state which attached the annular body 5. FIG. It is a top view of ignition device 1 in the state where annular body 5 was removed. It is a side view of the ignition device 1 of the state which removed the annular body 5. FIG. It is a top view of the ignition device 1 shown as other embodiment. It is a partially cutaway side view of the ignition device 1 shown as another embodiment. It is a top view of the ignition device 1 shown as other embodiment. It is a partially cutaway side view of the ignition device 1 shown as another embodiment. It is a perspective view of the member 81 comprised by the annular body 5 and the insulator 351 being integrated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition device 2 Ignition coil 215 Base part 3 Insulating case 30 Bottom surface 31 Open surface 32 Core storage cylinder 321 Top peripheral edge 322 Cut surface 35 Primary terminal 351 Insulator 4 Core 41 End surface 42 End surface 43 Earth terminal 5 Ring body 51 Projection unit 6 Ignition unit 71 First gap 72 Second gap 9 Resin

Claims (7)

  A case having an open surface and having a core storage tube projecting toward the open surface, and a core fitted inside the core storage tube so as to protrude from the top of the core storage tube; An ignition device for an internal combustion engine comprising: an ignition coil that is fitted to the outside of the core housing cylinder so that a top portion of the core housing cylinder projects from an end surface thereof; and a resin that is injected into the case and cured. An ignition device comprising: a resin-made annular body that is provided so as to surround the periphery of the top portion so as to form a gap with the periphery of the top portion of the core housing cylinder.   2. The ignition device according to claim 1, wherein the ignition coil includes a plurality of plate-like pedestal portions on which the annular body is mounted and intermittently projecting along a peripheral edge of the annular body. An ignition device characterized by.   3. The ignition device according to claim 2, wherein the ignition coil includes a primary bobbin around which a primary coil is wound, and a secondary bobbin in which the primary bobbin is accommodated and a secondary coil is wound. And an igniter characterized in that the pedestal portion protrudes from the outer peripheral side of the collar portion of the primary bobbin.   2. The ignition device for an internal combustion engine according to claim 1, wherein the annular body has a plate-like side surface provided in parallel with the side surface of the core housing cylinder.   2. The ignition device according to claim 1, comprising a primary terminal to which a signal line of an ignition unit is connected, and an insulator provided in the primary terminal, wherein the annular body is integrated with the insulator. An ignition device characterized by.   2. The ignition device according to claim 1, wherein the annular body has a plurality of protrusions formed intermittently along the inner surface on the inner surface, and the protrusion is the core or the core. An ignition device, wherein the ignition device is fitted to the side surface of the core or the core storage tube so as to contact the side surface of the storage tube. A case having an open surface and having a core storage tube projecting toward the open surface, and a core fitted inside the core storage tube so as to protrude from the top of the core storage tube; The peripheral edge of the top portion so as to form a gap between the ignition coil fitted on the outer side of the core storage tube so that the top portion of the core storage tube protrudes from the end surface thereof and the top peripheral edge of the core storage tube A method for manufacturing an ignition device for an internal combustion engine comprising a resin-made annular body provided to surround
Fitting the ignition coil to the core housing cylinder;
Providing the annular body on the periphery of the top of the core storage cylinder;
And a step of injecting resin into the case and curing the resin.

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