JP2008055881A - Mold for molded article with cylindrical core and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for a molded article with a cylindrical core which can properly vent the air in a cavity and also simplify a work of removing unnecessary parts of the molded article, and a method for manufacturing the mold. <P>SOLUTION: This mold is constituted so that a molding material of a rubbery elastic body 4 can be injected and filled into a cavity 8 formed around the periphery of an inner cylinder 2, and equipped with an injection hole 9 for injecting the molding material into the cavity 8, first hole parts 41 and 51 communicating with the cavity 8 through the gap between the upper face 5a of an upper mold or the lower face of a lower mold and the cavity 8, second hole parts 42 and 52 intersecting with the first hole parts 41 and 51 and extending to communicate with outside 28 of the mold side, and discharging holes 40 and 50 where surplus molding materials are fed so that the surplus molding material in the discharging holes 40 and 50 can be discharged to outside of the mold one after another. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding die and a manufacturing method for a molded product with a cylindrical core used mainly for a vibration isolating bush for a vehicle, a vibration isolating mount, and the like.

  As such a molded article with a cylindrical core body, a rubber core is provided between the inner cylinder as the cylindrical core body and the outer cylinder surrounding it, or the outer core is omitted and the cylindrical core is omitted. A rubber-like elastic body integrally formed on the outer periphery of the body is known. In addition, as a mold for the molded product with a cylindrical core body, an upper mold and a lower mold that can be clamped are provided, and a molding material for a rubber-like elastic body is injected into a cavity formed on the outer periphery of the cylindrical core body What is comprised so that filling is possible is common (for example, the following patent document 1).

  When the molding material of rubber-like elastic material is injected and filled into the cavity, the air in the cavity is discharged out of the cavity from the mating part of each mold due to the filling pressure of the molding material. May occur. On the other hand, when the filling pressure of the molding material is lowered, the occurrence of this burr is suppressed, but air tends to remain in the cavity, and a trace may remain in the molded product, which may cause molding defects.

  In order to eliminate such problems, Patent Document 2 below proposes a mold as shown in FIG. In this mold, an inner cylinder 61 as a cylindrical core body and an outer cylinder 62 surrounding the inner cylinder 61 are supported in an upright posture, and support pins 63 and 64 are inserted into the openings at the upper and lower ends of the inner cylinder 61. The support pins 63 and 64 have a locking step portion for locking the end portion of the inner cylinder 61, and constitute an annular hole portion 67 into which the end portion of the inner cylinder 61 is fitted together with the nested molds 65 and 66. .

  A cavity 68 is formed on the outer periphery of the inner cylinder 61, and a molding material injection hole 69 and an escape hole 80 communicate with the cavity 68 from the upper surface of the upper mold 90. A plurality of cavities 68 are formed in the mold, and the relief holes 80 communicating with the cavities 68 communicate with the relief holes of the other cavities via the relief grooves 81. Similar to the runner groove 92, the escape groove 81 is provided on the lower surface of the runner plate 91 that is configured to be separable from the upper mold 90.

  According to this mold, the air in the cavity 68 is discharged from the escape hole 80 by the filling pressure of the molding material injected through the injection hole 69. The surplus molding material that cannot be filled in the cavity 68 is fed into the escape hole 80, and the air contained in the surplus is simultaneously discharged. As a result, the air is sufficiently discharged out of the cavity, and the above-described problems can be solved.

  By the way, since the molding material sent into the escape hole 80 and the escape groove 81 becomes an unnecessary portion, it is necessary to remove it. In this mold, every time the runner plate 91 is separated from the upper mold 90 at the time of demolding, the operator pinches the portion formed on the small convex portion 83, pulls out the unnecessary portion in the escape hole 80, and further releases it. There is a problem that the work of removing unnecessary portions in the working groove 81 is required, and the man-hour is increased and the productivity is impaired. In addition, in order to perform an unnecessary portion removing operation, the setting position of the escape hole 80 is limited to the mold matching portion (the lower surface of the runner plate 91 in the illustrated example).

The following Patent Document 2 describes a configuration in which a relief groove communicates with the outside of the mold, but this is for ensuring the discharge of air out of the mold, and removal of unnecessary portions is performed. As described above, it is performed every time the worker demolds.
Japanese Utility Model Publication No. 2-15315 JP 2002-79551 A

  The present invention has been made in view of the above circumstances, and its purpose is to form a molded article with a cylindrical core body that can appropriately discharge the air in the cavity and simplify the removal of unnecessary parts of the molding material. It is to provide a mold and a manufacturing method.

  The above object can be achieved by the present invention having the following configuration. That is, the mold of the molded article with a cylindrical core body according to the present invention has a cavity formed on the outer periphery of the cylindrical core body when the upper mold and the lower mold are clamped directly or sandwiching the middle mold, In a mold for a molded article with a cylindrical core body configured to be able to inject and fill a molding material of a rubber-like elastic body, an injection hole for injecting the molding material into the cavity, and an upper surface of the upper mold or a lower surface of the lower mold A first hole that communicates with the cavity from between the first cavity and the second cavity, and a second hole that extends across the first hole and communicates with the outside of the mold. And an excess portion of the molding material in the discharge hole can be discharged out of the mold in a balance manner.

  The effects of molding a molded article with a cylindrical core using the mold according to the present invention will be described. In molding a molded article with a cylindrical core body, first, the cylindrical core body is set in a molding die, and the upper mold and the lower mold are clamped to form a cavity on the outer periphery of the cylindrical core body. The upper mold and the lower mold are clamped directly or in a state of sandwiching the middle mold.

  After forming the cavity, a rubber-like elastic molding material is injected into the cavity through the injection hole. The injected molding material is filled in the cavity, and a rubber-like elastic body is integrally formed on the cylindrical core. At this time, the air in the cavity is sent to the discharge hole and discharged by the filling pressure of the molding material. In addition, surplus molding material that cannot be filled in the cavity is also fed into the discharge hole, and the air contained in the surplus is discharged.

  Next, the upper mold and the lower mold are opened to remove the molded product. The discharge hole has a first hole portion that communicates with the cavity from between the upper surface or the lower surface of the lower mold and the cavity, and a second hole portion that extends across the first hole portion and communicates with the outside of the mold side. In addition, an unnecessary portion (a surplus of molding material fed into the discharge hole) can be left in the discharge hole at the time of demolding. And in the state which left the unnecessary part left, a new cylindrical core body can be set, a cavity can be formed, and the next molded product can be shape | molded.

  The molding die of the present invention is configured so that the excess of the molding material in the discharge hole can be discharged out of the mold in a temporary manner, and in the process of successively molding the molded product as described above, the discharge hole is intermittently formed. The excess of the molding material fed in is pushed out from the first hole through the second hole and discharged in a balance manner. For this reason, the removal operation | work of an unnecessary part can be simplified and workability | operativity can be improved significantly.

  In the above, it is preferable that the second hole portion has an inner diameter larger than that of the first hole portion. With this configuration, the excess molding material left in the first hole portion can be smoothly fed into the second hole portion, and the unnecessary portion can be smoothly discharged out of the mold without causing clogging.

  In the above, it is preferable that the first hole portion has an inner diameter that is gradually increased from the gate communicating with the cavity toward the second hole portion. Thereby, an unnecessary portion in the discharge hole can be easily separated from the rubber-like elastic body in the cavity, and an excess of the molding material can be smoothly fed from the gate toward the second hole. Such a configuration is particularly useful in a discharge hole provided in the upper mold, in which an excess of the molding material is pushed up and fed.

  In the above, it is preferable that the discharge holes are provided on both sides in the axial direction of the cavity, and the first hole portion is communicated with the vicinity of the end portion of the cylindrical core body of the cavity. According to such a configuration, an excess of the molding material can be fed into the discharge hole in the vicinity of the end of the cylindrical core body of the cavity on both axial sides of the cavity. As a result, it is possible to prevent the molding material from entering the end face of the cylindrical core body and to prevent the occurrence of end face burrs.

  Further, the method for producing a molded article with a cylindrical core of the present invention comprises injecting and filling a molding material of a rubber-like elastic body into a cavity formed on the outer periphery of the cylindrical core, so that the cylindrical core is rubbery. In the method of manufacturing a molded article with a cylindrical core body integrally molded with an elastic body, the molding material is injected and filled into the cavity through an injection hole, and a rubber-like elastic body is integrally molded with the cylindrical core body. A step of feeding the surplus of the molding material from the cavity to a discharge hole communicating with the outside of the mold, and removing the molded product while leaving the surplus of the molding material in the discharge hole, and forming a cylinder in the mold And forming a cavity by setting a core, and intermittently feeding the surplus portion of the molding material into the discharge hole, so that the surplus portion of the molding material in the discharge hole is out of the mold To be discharged.

  According to the method for manufacturing a molded article with a cylindrical core according to the present invention, the above-described effects are exhibited in molding the molded article with a cylindrical core. In other words, the air in the cavity can be properly discharged, and the removal of unnecessary parts of the molding material can be simplified by intermittently feeding the excess molding material into the discharge hole and discharging it out of the mold. Can greatly improve the performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an anti-vibration bush (an example of a molded article with a cylindrical core). FIG. 2 is a cross-sectional view of an essential part showing an example of a molding die of a molded article with a cylindrical core body according to the present invention. FIG. 3 is a schematic plan view of the entire mold, in which the right half shows the arrangement of the cavities in the upper mold and the left half shows the bottom surface shape of the runner plate.

  First, the anti-vibration bush 1 shown in FIG. 1 will be briefly described. This anti-vibration bush 1 is interposed between an inner cylinder 2 as a cylindrical core, an outer cylinder 3 concentrically surrounding the inner cylinder 2 and the inner cylinder 2 and the outer cylinder 3, and couples them together. A rubber-like elastic body 4 is provided. The inner cylinder 2 and the outer cylinder 3 can be formed of a known high-rigidity material, and for example, a steel material or a high-rigidity resin material can be used. Moreover, as the rubber-like elastic body 4, a known rubber material in the technical field of automobile vibration-proof rubber can be used without limitation.

  The inner cylinder 2 is longer in the axial direction than the outer cylinder 3, and both end portions 21 and 23 protrude from the axial side surface 4 a of the rubber-like elastic body 4. In some cases, both end faces 22 and 24 of the inner cylinder 2 are provided with sawtooth-shaped chevron grooves. In the present embodiment, two straight portions 25 penetrating the rubber-like elastic body 4 in the axial direction are provided at two locations facing the radial direction across the inner cylinder 2. A stopper 26 is fixed to the outer peripheral surface of the central portion in the axial direction of the inner cylinder 2.

  Next, the mold shown in FIG. 2 will be described. This mold includes an upper mold 5 and a lower mold 6 that are clamped with an intermediate mold 7 interposed therebetween, and a runner plate 20 that is separable from the upper mold 5 is laid on the upper mold upper surface 5a. A runner groove 27 communicating with the injection port 19 is provided on the lower surface of the runner plate 20. In addition, the runner groove | channel 27 is extended in the direction perpendicular | vertical to a paper surface in FIG.

  The inner cylinder 2 and the outer cylinder 3 are supported in an upright posture, and a cavity 8 is formed on the outer periphery of the inner cylinder 2. The injection hole 9 extends in the axial direction from the upper die upper surface 5 a and communicates with the cavity 8, and the upper end thereof communicates with the end portion of the runner groove 27. The molding material of the rubber-like elastic body 4 is injected and filled into the cavity 8 through the injection hole 9.

  In this mold, the nested molds 10 and 30 are arranged so as to face each other. The insert molds 10 and 30 have molding surface portions 11 and 31 having a shape corresponding to the axial side surface 4a of the rubber-like elastic body 4, and are fixed in a state of being fitted into the recessed portions 12 and 32, respectively. The projecting portions 17 and 37 project from the molding surface portions 11 and 31 toward the cavity 8, thereby forming a straight portion 25. At the center of the insert molds 10 and 30, annular hole portions 13 and 33 into which the end portions of the inner cylinder 2 are fitted are provided, and these are formed continuously with the molding surface portions 11 and 31.

  A support pin 14 that protrudes downward and is inserted from the upper end opening of the inner cylinder 2 is provided at the center of the annular hole 13 on the upper mold side. The support pin 14 is urged downward by a spring 16 attached to the base portion 15 in order to improve the demoldability of the molded product. The base 15 is formed with a locking step for locking the end surface of the inner cylinder 2, and a seal ring 18 is disposed on the outer periphery thereof.

  A support pin 34 that protrudes upward and is inserted from the lower end opening of the inner cylinder 2 is provided at the center of the annular hole 33 on the lower mold side. The base 35 of the support pin 34 is formed with a locking step for locking the end surface of the inner cylinder 2, and a seal ring 38 is disposed on the outer periphery thereof. The support pin 34 is configured to be able to be pushed up by an ejector provided continuously downward so that the molded product can be easily taken out at the time of demolding.

  The middle mold 7 includes a plurality of mold parts divided in the circumferential direction, and is configured to be displaceable in the radial direction between a position circumscribing the outer cylinder 3 and a position spaced from the outer cylinder 3. An inner peripheral flange portion 71 located above the outer cylinder 3 in a mold-clamped state is provided on the upper portion of the middle mold 7. The burr groove portion 72 is provided in an annular shape in contact with the inner peripheral flange portion 71 and communicates with the cavity 8 through a minute gap.

  Exhaust holes 40 and 50 through which surplus molding material is fed are provided on the side opposite to the injection hole 9 and the inner cylinder 2 by 180 degrees. The discharge hole 40 includes a first hole 41 that communicates with the cavity 8 from between the upper mold upper surface 5 a and the cavity 8, and a second hole 42 that extends across the first hole 41 and communicates with the mold-side exterior 28. Have Further, the discharge hole 50 includes a first hole 51 that communicates with the cavity 8 from between the lower mold lower surface and the cavity 8, and a second hole 52 that extends across the first hole 51 and communicates with the mold-side exterior 28. And have. As will be described later, the molding die is configured so that the excess of the molding material fed into the discharge holes 40 and 50 can be discharged out of the die in a place-type manner.

  The discharge hole 40 is formed such that the second hole portion 42 has a larger inner diameter than the first hole portion 41. The first hole 41 communicates with the vicinity of the end 21 of the inner cylinder 2 of the cavity 8 and is formed so that the inner diameter gradually increases from the gate 43 communicating with the cavity 8 toward the second hole 42. Has been. The inner diameter of the first hole 41 is 1 mm at the gate 43, 8 mm at the portion communicating with the gate 43, 12 mm at the portion communicating with the second hole 42, and the inner diameter of the second hole 42 is 15 mm. Illustrated.

  The discharge hole 50 is formed such that the second hole 52 has a larger inner diameter than the first hole 51. The discharge hole 50 has two first hole portions 51, which communicate with the second hole portion 52, the vicinity of the end 23 of the inner cylinder 2 of the cavity 8, and the end of the outer cylinder 3. It leads to the vicinity of the part. The first hole 51 extends in the axial direction from the gate 53 toward the second hole 52 without gradually changing the inner diameter.

  The molding die of this embodiment is configured so that 16 cavities 8 are formed, and the number of injection holes 9 and discharge holes 40 and 50, nesting molds 10 and 30, and support pins 14 and 34 corresponding to the number of cavities 8 are formed. Is provided in the upper die 5 or the lower die 6. Since the discharge holes 40 and 50 are formed independently of each other and do not communicate with the discharge holes of the other cavities, the excess of the molding material can be obtained without being affected by the molding conditions in the other cavities. It can be discharged out of the mold stably.

  Hereinafter, a method of manufacturing the vibration isolating bush 1 using the above-described mold will be described. First, as shown in FIG. 2, after setting the inner cylinder 2 and the outer cylinder 3 in the mold, the upper mold 5 and the lower mold 6 are clamped to form the cavity 8 on the outer periphery of the inner cylinder 2. . The inner cylinder 2 is in a state in which the end portions 21 and 23 are fitted into the annular hole portions 13 and 33 and is supported in an upright posture. The intermediate die 7 is displaced radially inward after the outer cylinder 3 is set and circumscribes the outer cylinder 3, and thereafter, the upper die 5 and the lower die 6 are clamped.

  Subsequently, the molding material of the rubber-like elastic body 4 is injected into the cavity 8 through the injection hole 9. A predetermined amount of the molding material is injected into each cavity 8 from the injection device through the injection port 19, the runner groove 27 and the injection hole 9. The injected molding material flows around the outer periphery of the inner cylinder 2 from the injection hole 9 side in the cavity 8 and flows to the discharge holes 40 and 50 side, and is filled in the cavity 8 as shown in FIG.

  The air in the cavity 8 is sent to the discharge holes 40 and 50 by the filling pressure of the molding material and discharged out of the cavity. Further, surplus molding material that cannot be filled in the cavity 8 is fed into the discharge holes 40 and 50, and the air still remaining in the cavity 8 is contained in the surplus and discharged.

  In the present embodiment, since the discharge holes 40 and 50 are provided on the sides opposite to each other by 180 degrees across the injection hole 9 and the inner cylinder 2, the excess molding material pushes air into the discharge holes 40 and 50. The air is discharged more smoothly. Since the air is pushed up by filling the molding material, it is preferable that the discharge holes are provided at least in the upper mold 5 and more preferably provided on both axial sides of the cavity 8 as in this embodiment. preferable.

  The first hole portions 41 and 51 lead to the vicinity of the end portions 21 and 23 of the inner cylinder 2 of the cavity 8, and the filling pressure does not become excessively high at the location where the molding material is sealed. Therefore, it is possible to prevent the molding material from entering the end surface of the inner cylinder 2 and to prevent the generation of end surface burrs. Such an end surface burr preventing effect is similarly exerted on the lower end portion of the outer cylinder 3. In addition, about the upper edge part of the outer cylinder 3, an end surface burr | flash can be prevented by sending the surplus part of a molding material into the burr groove part 72. FIG.

  When the molding material is filled in the cavity 8, the rubber-like elastic body 4 is integrally molded with the inner cylinder 2 and the outer cylinder 3. After the rubber-like elastic body 4 is molded, the upper mold 5 and the lower mold 6 are opened to release the vibration-proof bushing 1 that is a molded product. In the mold removal, first, as shown in FIG. 5, the middle mold 7 and the lower mold 6 are lowered and separated from the upper mold 5, and the runner plate 20 is raised and separated from the upper mold 5.

  When separating the middle mold 7 and the lower mold 6 from the upper mold 5, in this embodiment, the vibration isolating bush 1 is held against the lower mold 6 by the inner peripheral flange portion 71 of the middle mold 7, and the end portion 21 of the inner cylinder 2 is moved. It can be reliably removed from the annular hole 13. Therefore, the inner cylinder 2 does not hang from the upper mold 5 when the mold is opened, and the demolding operation is stabilized.

  When the runner plate 20 is separated from the upper mold 5, the unnecessary portion R <b> 1 in the discharge hole 40 is easily separated from the rubber-like elastic body 4 by the gate 43. Moreover, in this embodiment, since the edge part of the runner groove | channel 27 makes a truncated cone shape and makes a cross-section inverted trapezoid, the unnecessary part R2 in the injection hole 9 engages with the runner groove | channel 27, and the runner plate 20 raises. The unnecessary portion R2 can be pulled out from the injection hole 9 by using it. The operator can confirm that the unnecessary portion R2 is appropriately separated at the gate by looking at the tip of the unnecessary portion R2 that has been pulled out.

  Next, the middle mold 7 is displaced radially outward, and the anti-vibration bush 1 is taken out of the mold. The unnecessary portion R3 in the discharge hole 50 is easily separated from the rubber-like elastic body 4 by the gate 53. Although the annular burr 73 formed by the burr groove portion 72 is attached to the anti-vibration bush 1 that has been removed from the mold, it can be easily pulled apart because it is connected by a thin portion.

  The anti-vibration bush 1 is removed from the mold while the unnecessary portions R1 and R3 are left in the discharge holes 40 and 50. If the first hole 41 communicates with the upper mold upper surface 5a, it is difficult to remove the mold in a state where such an unnecessary portion R1 is left. After removing the mold, with the unnecessary portions R1 and R3 remaining in the discharge holes 40 and 50, as shown in FIG. 6, the new inner cylinder 2 and outer cylinder 3 are set to form the cavity 8, and the next prevention Shake the bushing.

  Subsequent molding is performed in the same manner as described above, but the injection filling of the molding material into the cavity 8 is performed in a state where the unnecessary portions R1 and R3 are left in the discharge holes 40 and 50. Even in such a case, the air in the cavity 8 is somewhat sent to the discharge holes 40 and 50 due to the filling pressure of the molding material, and is additionally contained in the excess molding material and discharged out of the cavity. There is no problem with air.

  In this way, by molding the anti-vibration bushes 1 one after another, the surplus of the molding material is intermittently fed into the discharge holes 40 and 50. Excess portions of the molding material sent to the discharge holes 40 and 50, that is, unnecessary portions R1 and R3, are pushed out of the discharge holes 40 and 50, and finally discharged from the mold-side outside 28 out of the mold.

  The second hole portion 42 of the discharge hole 40 is formed to have an inner diameter larger than that of the first hole portion 41, so that unnecessary portions are less likely to be clogged. In addition, the unnecessary portion R1 that has been heated and somewhat cured while remaining in the first hole 41 has a low resistance to the inner wall of the second hole 42, and is sent later. It can be easily moved forward by being pushed by the unnecessary portion R1. The same applies to the second hole 52 of the discharge hole 50.

  Further, the first hole 41 of the discharge hole 40 has an inner diameter that is gradually increased from the gate 43 toward the second hole 42, so that the unnecessary portion R <b> 1 is transferred from the gate 43 to the second hole 42. It can be smoothly fed in. In addition, in the 1st hole part 51 of the discharge hole 50, it is easy for the unnecessary part R3 to advance to the 2nd hole part 52 side by dead weight, and it is pushed forward by the unnecessary part R3 sent in later, and advances easily. Can do.

[Another embodiment]
The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention. For example, the vibration isolating bush omits the outer cylinder, or the upper mold. The lower mold and the lower mold may be directly clamped. Further, as the mold, the upper mold is provided with a discharge hole such as the discharge hole 50 described above, in which the first hole portion extends in the axial direction and leads to the vicinity of the end portions of the inner cylinder and the outer cylinder of the cavity. It doesn't matter.

Cross section of anti-vibration bush Cross-sectional view of the relevant part showing an example of a mold for a molded article with a cylindrical core Schematic plan view of the same mold Cross-sectional view of the main part showing the molding material injected into the mold Cross section of the main part showing the mold open state of the same mold Cross-sectional view of the main part showing the clamping state of the same mold Sectional drawing which shows an example of the shaping | molding die of the conventional molded article with a cylindrical core

Explanation of symbols

1 Anti-vibration bush (molded product with cylindrical core)
2 Inner cylinder (cylindrical core)
3 outer cylinder 4 rubber-like elastic body 5 upper mold 5a upper mold upper surface 6 lower mold 7 middle mold 8 cavity 9 injection hole 20 runner plate 28 mold side external 40 discharge hole 41 first hole 42 second hole 43 gate 50 discharge hole 51 1st hole 52 2nd hole 53 Gate R1 Unnecessary part R2 Unnecessary part R3 Unnecessary part

Claims (5)

When the upper mold and the lower mold are clamped directly or with the middle mold sandwiched, a cavity is formed on the outer periphery of the cylindrical core body, and the cavity is configured so that a rubber-like elastic molding material can be injected and filled. In molds for cored molded products,
An injection hole for injecting the molding material into the cavity;
A first hole communicating with the cavity from between the upper surface of the upper mold or the lower surface of the lower mold and the cavity; and a second hole extending across the first hole and communicating with the outside of the mold, A discharge hole into which surplus molding material is fed,
A molding die for a molded article with a cylindrical core, characterized in that the excess of the molding material in the discharge hole can be ejected out of the die in a place-type manner.   The mold of the molded article with a cylindrical core body according to claim 1, wherein the second hole portion has an inner diameter larger than that of the first hole portion.   The molding die for a molded article with a cylindrical core body according to claim 1 or 2, wherein the first hole portion has an inner diameter formed in a stepwise manner from the gate communicating with the cavity toward the second hole portion.   The said discharge hole is provided in the axial direction both sides of the said cavity, and the said 1st hole is connected to the edge part vicinity of the said cylindrical core body of the said cavity. Mold for molded products with a cylindrical core. In a method for manufacturing a molded article with a cylindrical core body, in which a molding material of a rubber-like elastic body is injected and filled into a cavity formed on the outer periphery of the cylindrical core body, and the rubber-like elastic body is integrally formed with the cylindrical core body. ,
The molding material is injected and filled into the cavity through an injection hole, and a rubber-like elastic body is integrally formed on the cylindrical core body, and an excess of the molding material is discharged from the cavity to the outside of the mold side. Sending process,
A step of removing a molded product while leaving an excess of the molding material in the discharge hole, setting a cylindrical core body in the mold, and forming a cavity,
A molded article with a cylindrical core body, wherein the excess of the molding material is intermittently fed into the discharge hole to discharge the excess of the molding material in the discharge hole out of the mold. Manufacturing method.

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