JP2006289996A - Mold for molded article with cylindrical core body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold capable of molding into a molded article with a cylindrical core body by surely discharging air near the top end part and without generating end face burrs. <P>SOLUTION: Insert molds 12 and 22 with fitting hole parts 14 and 24 at the centers are respectively provided in mold-closable top mold 10 and bottom mold 20. A supporting pin 25 fitted and locked to the cylindrical core body 1 is provided in the fitting hole part 24 on the lower side, and a core body presser foot 15 is provided in the fitting hole part 14 on the upper side, to form a cavity 30 on the outer periphery of a cylindrical core body 1 under the condition that the mold is closed, and in the mold, a molding material is filled in the cavity and molded. A seal ring 16 is provided in the fitting hole part 14 in the top side inserting mold 12 so that it is fitted into the fitting hole part 14 while air permeability is slightly held to the outer periphery of the upper end part of the cylindrical core body 1. An feeding hole 33 for the molding material, and a relief hole 35 for air and the molding material are provided on the top mold 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding die for a molded article with a cylindrical core used mainly for a vibration isolating rubber bush for a vehicle or a vibration isolating mount.

  As an anti-vibration rubber bush or anti-vibration mount for vehicles, a rubber elastic body is interposed between the cylindrical core body as the inner cylinder and the outer cylindrical member, or the outer cylindrical member is omitted and is surrounded around the cylindrical core body. A rubber elastic body having a cylindrical shape is known.

  As a molding die for a cylindrical cored molded product such as a vibration-proof rubber bush, the axial side surface of the molded product is generally opposed to the upper and lower cavities in both upper and lower mold cavities. A support pin is provided at the center of at least one of the upper and lower molds, for example, both of the insert molds, and the end of the cylindrical core body is fitted to the support pin. In addition, in a state where both ends are locked and supported in an upright state and the upper and lower molds are closed, a cavity is formed around the cylindrical core body, and a molding material such as rubber is injected into the cavity from the injection hole. It is formed by injection filling (for example, Japanese Utility Model Publication No. 5-28020, Japanese Patent Laid-Open No. 7-276382).

  By the way, the part protruding above and below the cavity of the cylindrical core body supported as described above is fitted into the fitting hole part at the center part of the upper and lower nesting type, and the upper and lower ends have the supporting pin. The molding material that is locked to the locking step portion, but injected into the cavity passes through the gap between the end portion of the cylindrical core body and the inner peripheral surface of the fitting hole portion on the outer periphery thereof, and the cylindrical core It penetrates into a slight gap between the end surface of the body and the engaging step portion to form an end surface burr.

  If the end of the cylindrical core is tightly fitted to the inner periphery of the fitting hole so that the gap between the two is substantially zero, it will not easily come off during mold release after molding, and workability will be improved. Will be inhibited. In addition, if it is held in a completely tightly fitted state, the air in the cavity may not be completely exhausted, especially if air remains in the vicinity of the upper end, the trace remains on the molded product, causing the occurrence of molding defects become.

Therefore, in Japanese Patent Laid-Open No. 7-276382, a bush capable of tightly fitting a predetermined dimension of the end inner peripheral surface of the cylindrical core body is provided on the inner periphery of the telescopic fitting hole, It is shown that the end is fitted and supported on the bush.
Japanese Utility Model Publication No. 5-28020 JP 7-276382 A

  However, in the proposed bush, since it is tightly fitted, that is, a tightly fitting structure, a special means for releasing the tightness when the mold is opened, for example, A knockout means such as a spring or a stick is required. In addition, especially when the upper end of the cylindrical core body is closely fitted to the bush in the upper nesting type fitting hole, the highest part of this cavity becomes an air reservoir, and the molding material The air is not completely discharged even by injecting and filling the air, resulting in a defect due to air remaining. Normally, air escapes from the escape of the mold from the mating part of each mold, but burrs may occur at the mating part of this mold.

  Further, when the filling pressure of the molding material to be injected and filled into the cavity is lowered, the occurrence of the burrs is reduced, but defects due to the air remaining inside are likely to occur. Therefore, the injection filling pressure is set so as not to cause the above-mentioned problems as much as possible. However, there is still no defect or burrs due to residual air, which is insufficient.

  Further, in a mold having a single molding material injection device, when a plurality of cavity components are provided, the injection filling pressure into the cavities in each cavity component is constant for the uniformity of the molded product. It is required to do.

  The present invention has been made in view of the above, and provides a mold capable of reliably discharging air in the vicinity of the upper end portion of a cylindrical core body and eliminating the occurrence of end surface burrs. Furthermore, in the case where a large number of cavity components are provided, a mold for a molded article with a cylindrical core body is provided in which the injection filling pressure of the molding material into each cavity is kept constant. is there.

  The present invention includes a mold for a molded article with a cylindrical core, that is, a nested mold that molds the axial side surfaces of the molded article with a cylindrical core facing each other vertically and sandwiches the intermediate mold directly or between the molds. The upper mold and the lower mold that can be closed with each other have a fitting hole for supporting the end of the cylindrical core set in the mold at the center of both the upper and lower nesting molds. The fitting hole on the lower mold side is provided with a support pin that fits into the cylindrical core body from the lower end opening and locks the lower end, and the fitting hole on the upper mold side is concentric with the support pin. The cylindrical core body is provided with a core body presser that is opposed to and locked to the upper end of the cylindrical core body, and is locked and supported by the support pin and the core body presser when both the upper and lower molds are closed. A cavity is formed on the outer periphery of the tube, and the cavity is filled with a molding material such as rubber and molded integrally with the cylindrical core. As a means for solving the above-mentioned problem, the fitting hole portion in the upper mold side nesting die has a slight air permeability with respect to the outer periphery of the upper end portion of the cylindrical core body. A sealing ring to be fitted is provided, and further includes a molding material injection hole that communicates from the upper surface of the upper mold to the cavity, and an escape hole for air and molding material that communicates from the cavity to the upper surface of the upper mold. It is characterized by.

  According to this mold, in a state where the cylindrical core body is supported and closed, the molding material such as rubber injected into the cavity through the injection hole is filled from the lower part around the cylindrical core body. As a result, the internal air is pushed upward and discharged from the escape hole, and the excess of the molding material is filled in the escape hole, thereby remaining in the molding material. Air is discharged at the same time.

  Also, the air that accumulates in the vicinity of the upper end of the cylindrical core is discharged from a very small gap with the seal ring fitted to the outer periphery of the upper end of the cylindrical core due to filling of the molding material, and almost remains. There is no.

  In addition, when vulcanized in this state, the filling pressure of the molding material in the cavity does not become excessively high, so that the molding material protrudes from a slight gap between the seal ring and the end of the cylindrical core. Does not occur, thus preventing the formation of burrs.

  In the molding die, it is preferable that the injection hole for the molding material and the escape hole in the upper die are provided at positions opposed to each other by 180 degrees across the axis of the cavity. As a result, the molding material injected from the injection hole goes around both sides of the cylindrical core and fills the entire cavity, and a part of the molding material blows air from the escape hole located opposite to the injection hole. It is escaped as it is pushed out, and air can be discharged well.

  In the molding die, a runner plate is detachably mounted on the upper surface of the upper die, and a runner groove for injection of molding material and a groove for air and molding material release are respectively provided on the lower surface of the runner plate. Those formed so as to be continuous with the injection hole or the relief hole are preferable. Thereby, the injection filling operation of the molding material and the excess molding material and air escape operation can be performed smoothly and satisfactorily.

  Further, in the molding die, a sealing member for receiving a core body that fits in a fitting hole portion in the lower mold side nesting die while the lower end portion of the cylindrical core body has slight air permeability. Are preferably provided. Thereby, it is possible to satisfactorily prevent the occurrence of burrs at the lower end portion of the cylindrical core body.

  The support pin in the molding die is displaceable upward in the axial direction, is biased downward by a return spring and is supported at a fixed position, and the return spring is appropriately pushed up by a push-up means at the time of mold release. If it is provided so as to be pushed up against the urging force, the lower end portion of the cylindrical core body can be easily detached from the fitting portion of the seal member by this pushing action, and the die can be easily removed.

  The core body presser is supported so as to be axially displaceable within a predetermined size range, and is urged downward in the axial direction by a spring means to attach the spring means in a mold-closed state in which the cylindrical core body is supported. It is preferable that the cylindrical core is pressed by the force and is displaced downward in the axial direction by opening the mold so that the upper end of the cylindrical core is detached from the fitting portion of the seal ring. That is, even if there is an error in the axial dimension of the cylindrical core body, the cylindrical core body can be pressed by the urging force of the spring means, and can be held stably. Moreover, the upper end portion of the cylindrical core body is naturally detached from the fitting portion of the seal ring due to the core body presser being displaced downward in the axial direction by the biasing force of the spring means due to the mold opening after molding. become. As a result, the molded product can be left on the lower side, thereby facilitating the die-cutting operation of the molded product.

  As the above-mentioned molds, the upper and lower molds are provided with a plurality of cavity constituent parts each including a nested mold, a support pin and a core presser, which are opposed to each other in the upper and lower parts. It is preferable that the injection hole is arranged at an equal distance from the injection port of the injection device. In this way, the injection distance into each cavity is the same, and the injection amount and injection filling pressure are equal, even though the molding material is injected and filled into the many cavities from the injection port of one injection device. become.

  Further, the cavity constituent parts are arranged on the same circle centering on the injection port of the injection device, and the injection holes of the respective cavity constituent parts are arranged concentrically so as to be equidistant from the injection port. Thus, the injection distance from the injection port to each cavity can be easily adjusted.

  In the above-mentioned mold, it is preferable that the relief holes of the respective cavity constituent parts are continuous with the relief grooves provided in the runner plate and communicate with the outside of the mold side, thereby leading from the relief holes to the relief grooves. The excess molding material portion is in a continuous state, and the removal work after molding can be easily performed.

  Further, the escape groove on the runner plate in the molding die has a circular shape centering on the injection port of the injection device, and a protruding molding portion for molding a small convex portion is provided at the upper end of each escape hole. Those are preferred. Thereby, the excess part shape | molded in each escape hole can be extracted and removed without difficulty from the escape hole.

  Further, in the molding die, an injection hole and a relief hole for each cavity component are provided on the radiation passing through the axis of the cavity component with the injection port of the injection device as the center. The flow of the molding material from the filling of the molding material to the relief hole becomes smooth, so that the filling state of the molding material and the discharge of air are surely performed, and the occurrence of molding defects can be reduced.

  According to the molding die of the present invention, air can be reliably discharged near the upper end of the cylindrical core body, the occurrence of molding defects can be reduced, and the occurrence of end surface burrs can be eliminated. The work can be eliminated, the man-hours can be greatly reduced, and the production efficiency can be improved. Further, when a large number of cavity constituent parts are provided, the injection filling pressure of the molding material into each cavity can be kept constant, and a uniform molded article with a cylindrical core can be efficiently manufactured.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  FIG. 1 is a longitudinal sectional view of a mold opening state showing an outline of one cavity constituting part of one embodiment of a molding die according to the present invention, FIG. 2 is a longitudinal sectional view of the molding state of the same, and FIG. 3 is a cylinder to be molded. FIG. 4 is a schematic plan view showing the arrangement of the cavity components in the upper mold of the entire mold, and FIG. 5 is placed on the mold shown in the previous figure. It is plane explanatory drawing which shows the lower surface shape of the runner plate made.

  As shown in FIG. 3, the molded article with a cylindrical core body (A) to be molded has a rubber elastic body (3) between a cylindrical core body (1) as an inner cylinder and an outer cylinder member (2). The rubber elastic body (3) is vulcanized and bonded to both the cylindrical core body (1) and the outer cylinder member (2). Usually, the said cylindrical core (1) is longer than an outer cylinder member (2), and the both ends protrude from the axial direction both sides | surface of a rubber elastic body (3).

  A molding die according to the present invention is for molding the above-described molded article with a cylindrical core (A), and has a cavity component (5) shown in FIGS. 1 and 2, and has the following configuration. I have.

  In the figure, (10) and (20) indicate an upper mold and a lower mold that can be closed, and are provided with recesses (11) and (21) for forming cavities vertically opposite to each other. ) And (21), the insert molds (12) and (22) for molding the axial side surfaces of the molded article (A) with the cylindrical core body are fitted and fixed opposite to each other. (23) indicates a fixing screw of the lower nesting type (22). Similarly, the upper mold (12) is fixed by a fixing screw (not shown). (50) is a base plate for receiving and supporting the lower mold (20).

  The upper and lower ends (1a) and (1b) of the cylindrical core body (1) set in the mold are respectively provided in the central part of the nested molds (12) and (22) of the upper and lower molds (10) and (20). There are fitting hole portions (14) and (24) to be supported, and these fitting hole portions (14) and (24) are molding surface portions (12a) and (22a) that form axial side surfaces of the molded product (A). To a predetermined curved surface corresponding to the molding shape.

  The fitting hole (24) on the lower mold (20) side protrudes upright so as to be fitted from the lower end opening into the cylindrical core (1) at the center and to lock the lower end. Support pins (25) are provided. (25a) shows the step part for latching a lower end provided in the base part of the fitting pin part (25b).

  Further, the fitting body (14) on the upper mold (10) side has a core body concentric with the support pin (25) and vertically opposed to the upper end of the cylindrical core body (1). A presser foot (15) is provided. (15a) shows a step for locking the upper end. In the case of the figure, this core body presser (15) also has a slightly short insertion pin portion (15b) that fits into the upper end portion of the cylindrical core body (1) set in the mold.

  Thus, in a state where the upper and lower molds (10) and (20) are closed, a cavity is formed on the outer periphery of the cylindrical core body (1) which is locked and supported by the support pin (25) and the core body presser (15). (30) can be formed.

  Furthermore, the inner periphery of the fitting hole (14) of the upper nesting mold (12) has a moderate air permeability at the inner back of the inner periphery of the upper end of the cylindrical core (1). There is also provided a seal ring (16) made of a rigid body such as metal that fits with a slight clearance that can suppress the leakage of the molding material.

  In other words, the seal ring (16) can prevent leakage of the molding material while the outer periphery of the upper end of the cylindrical core body (1) has a suitable air permeability that allows air to be discharged during molding, and the mold after molding. The inner diameter dimension is set according to the outer diameter of the end portion of the cylindrical core body (1) so as to maintain a fitting state that does not hinder removal. For example, since the adhesive layer is provided on the surface of the cylindrical core (1), the inner diameter of the seal ring (16) is set in consideration of the thickness of the adhesive layer. The outer diameter is slightly larger than the outer diameter. The clearance between the inner periphery of the seal ring (16) and the outer periphery of the cylindrical core (1) is preferably in a very small size range of 0.1 mm or less.

  In addition, the lower end outer periphery of the cylindrical core body (1) is fitted to the inner periphery of the inner part of the lower fitting hole (24) of the lower insert type (22) while maintaining a slight air permeability. A ring-shaped seal member (26) for receiving a core body made of a rigid body is provided. For the seal member (26), the inner diameter of the fitting portion and the like are set in the same manner as in the case of the seal ring (16). In the case of the figure, a locking step (26a) having the same height as the step (25a) is formed at the lower end of the fitting portion of the seal member (26), and the cylindrical core (1) Can be locked at both step portions (25a) and (26a). The base of the support pin (25) is supported by being fitted below the step (26a).

  The upper and lower nesting molds (12) and (22) are fitted to hold the outer cylinder member (2) of the molded article (A) with the cylindrical core concentrically with the cylindrical core (1) on the outer periphery thereof. Steps (17) and (27) are provided. When the upper and lower molds (10) and (20) are closed as shown in FIG. 1, the upper and lower end faces of the outer cylinder member (2) are pressed from above and below. It can be fitted and held in the sandwiched state. When molding a molded product having no outer cylinder member (2), the inner surface of the recess (11) (21) is formed so as to mold the outer circumferential surface of the molded product.

  (31) is a holding ring for the lower nesting die (22), which is fixed to the lower die (20) by a fixing screw (32) such as a bolt, and is set as described above. (2) is adapted to be fitted to the inner periphery of the presser ring (31). This also prevents the outer cylindrical member (2) from bulging and deforming during molding.

  The support pin (25) is axially displaceable. An eject pin (28) is connected to the support pin (25), and a spring seat (28a) at the lower end of the eject pin (28). ) And the lower die (20) are provided with a return spring (29) that urges the support pin (25) downward to hold it in place (position shown in FIG. 2). When the die is removed, the eject pin (28) is appropriately pushed up by a pushing-up means (not shown) against the urging force of the return spring (29), thereby moving the molded product (A). The lower end portion (1b) of the cylindrical core body (1) can be detached from the fitting portion of the seal member (26).

  The upper core presser (15) is also supported so as to be displaceable in the axial direction within a predetermined size range as described in the embodiments of FIGS. 6 and 7, which will be described later. It is configured so that the upper end (1a) of the cylindrical core body (1) of the molded product (A) is detached from the seal ring (16) when urged downward in the direction when the mold is removed after molding. It is preferable to do this.

  (33) is an injection hole of a molding material (a) such as rubber that communicates from the upper surface (10a) of the upper mold (10) to the cavity (30), and (35) is the upper mold (10) from the cavity (30). Air and a release hole for the molding material (a) and the like, and is provided through the upper mold (10) and the insert mold (12) in the vertical direction. The injection hole (33) and the escape hole (35) may be located at any position above the cavity (30), but in practice, approximately 180 with the axis of the cavity (30) sandwiched as shown in the figure. It is desirable to provide them at opposite positions.

  The injection hole (33) and the relief hole (35) are both tapered toward the upper surface (10a) and constricted near the opening end on the cavity (30) side. The gates (33a) and (35a) are provided so that the molded product (A) can be separated from the unnecessary portions (a1) and (a2) at the locations of the gates (33a) and (35a) when the die is cut after molding. It is like that.

  (40) is a runner plate that is detachably mounted on the upper surface (10a) of the upper mold (10). When the upper and lower molds (10) and (20) are opened, the runner plate (40) Can be separated from the upper mold (10). (41) shows a spring for separating the runner plate (40).

  On the lower surface of the runner plate (40), a runner groove (43) for injecting a molding material such as rubber and a groove (45) for releasing air and molding material are closed with respect to the upper surface of the upper mold (10). It is sometimes formed to be continuous with the injection hole (33) or the escape hole (35) of the upper mold (10). The runner groove (43) is continuous with the injection port of the injection device, and the escape groove (45) is opened to the side of the mold. (44) is a connection end portion of the runner groove (43) to the injection hole (33), and has a circular shape slightly larger in diameter than the opening diameter of the injection hole (33). (46) is a projecting molding portion provided at the connection portion of the relief groove (45) with the relief hole (35), and the upper end of the unnecessary portion (a2) of the molding material in the relief hole (35) This is for forming a small convex portion (a3).

  As the mold, the cavity component (5) having the above-described configuration, that is, the opposite nesting dies (12) and (22), the support pin (25), the core presser (15), etc. 10) A plurality of cavity components (5) provided in (20) are arranged and carried out. In this case, the runner grooves (43) from the injection port (6) of the injection device to the injection hole (33) of the molding material into the cavity (30) in each cavity component (5) are arranged at equal distances. It is particularly preferable that the filling amount and the filling pressure of the molding material into each cavity (30) can be made substantially uniform.

  For example, as shown in FIGS. 4 and 5, even number of the cavity constituent portions (5) are arranged on the same circle centering on the injection port (6) of the injection device, and the injection holes (33) are arranged respectively. The escape holes (35) are also preferably arranged on the same circle centered on the injection port (6). In practice, it is preferable that the injection hole (33) and the escape hole (35) are provided on the radiation passing through the axis of the cavity component (5) with the injection port (6) as the center. . The runner groove (43) and the escape groove (45) are preferably provided so that the injection hole (33) and the escape hole (35) are continuous.

  That is, for the runner groove (43), two adjacent cavity constituent parts (5) are set as one set, and one runner groove extending in the radial direction from the injection port (6) is provided for each set. The portion is bifurcated and connected to the injection holes (33) and (33) of both the cavity components (5) and (5) so as to be equidistant from the injection port (6) to each injection hole (33). Configure and implement.

  The escape groove (45) is also formed in a circular shape with the injection port (6) as the center, and the escape holes (35) are formed so as to be continuous with the circular portion (45a). Further, the groove portion (45b) extending outward from the circular portion (45a) is communicated with the outside of the mold side. Also in this case, at each intersection of the circular portion (45a) with the escape hole (35), a protruding molded portion (a3) for forming a small convex portion (a3) at the upper end of the escape hole (35) ( 46) should be provided.

  In the above-described mold, the upper and lower molds (10) and (20) open / close means, the drive means, the runner plate (40) open / close means, and the guide means for opening and closing are of this type. Since well-known means can be used, detailed description is omitted. Although not shown, the upper and lower molds (10) and (20) can be provided via an intermediate mold so that the mold can be closed.

  An operation state in which, for example, the molded article with the cylindrical core body (A) shown in FIG. 3 is molded by the molding die having the configuration of the above-described embodiment will be described.

  First, the cylindrical core body (1) and the outer cylinder member (2) are set in the mold open state in which the upper mold (10) is separated from the lower mold (20) (chain line in FIG. 1). That is, the cylindrical core (1) is fitted to the support pin (25) having the lower die (20) side insert (22) and the lower end (1a) is fitted to the fitting hole (24). Then, the lower end is locked to the locking step (25a) and supported in an upright state. Further, the outer cylinder member (2) is fitted and set to the fitting step (27) of the outer peripheral portion of the telescopic mold (22).

  Next, when the upper mold (10) is lowered and the upper and lower molds (10) (20) are closed together, the fitting hole (14) of the nested mold (12) of the upper mold (10) is associated with this. ) Is fitted to the upper end (1a) of the cylindrical core (1), and the seal ring (16) provided on the inner periphery thereof is fitted to the outer periphery of the upper end (1a). The step (15a) of 15) is locked to the upper end to hold down the cylindrical core (1). At the same time, the fitting step portion (17) on the outer peripheral portion of the nested die (12) is fitted to the upper end portion of the outer cylinder member (2).

  Therefore, in the closed state of the upper and lower molds (10) and (20), the cylindrical core body (1) set inside is supported by the lower support pin (25) and the upper core body presser. (15) pressed and supported from above and below, and the outer periphery of the upper end (1a) of the cylindrical core (1) is fitted into the seal ring (16) on the inner periphery of the upper fitting hole (14) Held together. When the seal member (26) is provided on the inner periphery of the lower fitting hole (24) as shown in the figure, the lower end (1b) of the cylindrical core (1) is fitted to the seal member (26). Held together. Similarly, the outer cylinder member (2) is also held in a fitted state by the fitting step portions (17) and (27) of the upper and lower nested types (12) and (22). As a result, a cavity (30) surrounded by the upper and lower nested molds (12) and (22) and the outer cylinder member (2) is formed around the cylindrical core (1).

  Therefore, the molding material (a) injected from the injection port (6) of the injection device is passed through the runner groove (43) of the runner plate (40) and the injection hole (33) of the upper mold (10), and the cavity (30). A predetermined amount is injected and filled at a predetermined pressure. At this time, as shown in FIGS. 4 and 5, the mold has a plurality of cavity components (5), and each injection hole (33) is set at an equal distance from the injection port (6). Then, the injection amount and injection filling pressure of the molding material (a) in each cavity component (5) become uniform.

  Thus, in the cavity component (5), the molding material (a) injected into the cavity (30) from the injection hole (33) goes around both sides of the cylindrical core (1) from the injection hole (33) side. Then, the fluid flows toward the opposite relief holes (35), and the air in the cavity (30) is filled while being discharged from the relief holes (35). After the cavity (30) is filled with the molding material (a), the excess molding material is discharged from the escape hole (35). At this time, the air remaining in the cavity (30) is also included in the molding material (a) and discharged.

  In particular, the injection hole (33) and the escape hole (35) of each of the plurality of cavity components (5) are provided at positions 180 degrees opposite to each other on the radiation centering on the emission port (6). As a result, the flow of the molding material (a) from the injection hole (33) to the escape hole (35) becomes smooth, so that the molding material (a) is filled and discharged with certainty.

  Thus, vulcanization molding is performed while maintaining a predetermined filling pressure. At this time, the outer periphery of the upper end (1a) of the cylindrical core body (1) is fitted to the seal ring (16) on the inner periphery of the upper fitting hole (14). And the outer periphery of the upper end (1a) are fitted with a slight clearance so that leakage of the molding material can be regulated while having air permeability, so that the cylinder at the upper position in the cavity (30) The air remaining in the gap between the core (1) and the fitting hole (14) is discharged from the clearance between the seal ring (16) and the upper end (1a). It does not cause molding defects due to accumulation.

  Moreover, the clearance between the seal ring (16) and the upper end (1a) of the cylindrical core (1) is very small, and the cylindrical core (1) and the fitting hole (14) (24). The molding material (a) that has entered the gap does not leak out from the clearance between the seal ring (16) and the cylindrical core body (1), and therefore generation of burrs can be prevented.

  The same applies to the fitting portion between the sealing member (26) of the lower fitting hole (24) and the lower end (1b) of the cylindrical core (1), and the molding material (a) Generation of burrs due to leakage can be prevented.

  After the molding, the upper and lower molds (10) and (20) are opened, the runner plate (40) is separated from the upper surface (10a) of the upper mold (10), and the cored molded product (A) is obtained. Take out. At this time, the rubber elastic body (3) of the molded product (A) is separated from unnecessary portions in the injection hole (33) and the escape hole (35) from the gates (33a) and (35a), and the molded product ( Remove A) from the mold.

  When the molded product (A) is punched, the lower support pin (25) is pushed upward by the eject pin (28), so that the lower end (1b) of the cylindrical core (1) is sealed with a seal member ( 26) can be easily detached from the fitting part.

  Also, the unnecessary portion (a1) remaining inside the injection hole (33) is extracted together with the unnecessary portion remaining in the runner groove (43), and remains in the escape hole (35). Pull out the unnecessary part (a2) holding the small convex part (a3), and remove the unnecessary part in the escape groove (45). At this time, if the plurality of escape holes (35) are continuous by the escape grooves (45) as shown in the illustrated embodiment, the removal operation can be easily performed.

  6 and 7 show another embodiment of the mold according to the present invention for forming a molded article (A) with a cylindrical core body in the same manner as the above-described embodiment, and in particular, the upper core body presser (15 )), The case where a spring means is used to facilitate the removal of the molded product (A) at the time of die cutting is shown. In these examples, the same components and members as those in the above-described examples are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the embodiment of FIG. 6, the upper core presser (15) is fitted so as to be slidable in the axial direction (vertical direction) with respect to the holding cylinder (51) fixed to the inner periphery of the seal ring (16). In addition, the stepped portion (15c) having an enlarged diameter at the outer peripheral upper portion of the core body presser (15) has a small diameter at the inner peripheral lower portion of the holding cylinder (51) within a predetermined size range. Between the position away from the stepped portion (51a) (state of FIG. 6) and the position where the stepped portion (15c) engages with the stepped portion (51a), it is provided so as to be vertically displaceable. Then, a coil spring (53) serving as a spring means for urging the core body presser (15) downwardly in a storage portion (52) formed between the core body presser (15) and the upper mold (10). ) Is stored in a compressed state.

  As a result, in a state where the cylindrical core body (1) is supported and the mold is closed, the core body presser (15) can absorb the dimensional error and elastically hold the cylindrical core body (1). The upper end (1a) of the cylindrical core (1) is naturally and easily separated from the fitting part with the seal ring (16) by projecting and displacing downward in the axial direction by the mold opening after molding. Can be done.

  In the embodiment of FIG. 7, the core body presser (15) is fitted to the inner periphery of the seal ring (16) so as to be displaceable in the axial direction (vertical direction), and the upper part of the core body presser (15). An engaging member (55) such as a bolt is connected to the upper die (10) by screwing means, and the upper end head (55a) of the engaging member (55) is connected to the upper surface of the upper die (10). By being engaged with the bottom surface of the recess (56) on the side, it is supported so as not to be displaced downward beyond a predetermined position. A plurality of disc springs (57) serving as spring means for biasing the core presser (15) downward are overlapped between the core presser (15) and the lower surface of the upper mold (10). Arranged.

  Also in this case, when the cylindrical core body (1) is supported and the mold is closed, the core body presser (15) elastically presses the cylindrical core body (1) by the urging force of the disc spring (57). The upper end (1a) of the cylindrical core body (1) can be easily removed from the fitting portion with the seal ring (16) by being displaced downward in the axial direction by the mold opening after molding. Can be withdrawn. (58) is a filling of the recess (56).

  As shown in FIG. 8, the molded article with a cylindrical core body (A) to be molded may have an axial through hole (3a) in the rubber elastic body (3). 6 and 7, the upper and lower nested molds (12) and (22) may be provided with protrusions (12b) and (22b) corresponding to the through holes, respectively.

It is a longitudinal cross-sectional view which shows the outline of one cavity structure part in the shaping | molding die of one Example of this invention. It is a longitudinal cross-sectional view of a shaping | molding state same as the above. It is a perspective view which shows an example of the molded article with a cylindrical core body to be molded. It is a schematic plane explanatory drawing which shows the arrangement | positioning state of the cavity structure part in the upper mold | type of the whole shaping | molding die. It is a schematic plane explanatory drawing which shows the lower surface shape of the runner plate mounted on the shaping | molding die of a previous figure. It is a longitudinal cross-sectional view of the mold closing state which shows the outline of one cavity structural part in the shaping | molding die of the other Example of this invention. It is a longitudinal cross-sectional view of the mold closing state which shows the outline of one cavity structural part in the shaping | molding die of the further another Example of this invention. It is a longitudinal cross-sectional view which shows the other example of the molded article with the cylindrical core body of shaping | molding object.

Explanation of symbols

(A) Molded product with cylindrical core (a) Molding material (a1) (a2) Unnecessary part (a3) Small convex part (1) Cylindrical core (1a) (1b) Upper and lower ends (2) Outer cylinder Member (3) Rubber elastic body (5) Cavity component (6) Injection port of injection device (10) Upper mold (10a) Upper surface (20) Lower mold (11) (21) Recess for cavity formation (12) ( 22) Nested type (14) (24) Fitting hole (15) Core holder (16) Seal ring (25) Support pin (26) Seal member (25a) (26a) Stepped part (17) (27) Fitting Joint (30) Cavity (31) Presser ring (33) Injection hole (35) Relief hole (33a) (35a) Gate (40) Runner plate (43) Runner groove (45) Relief groove (51) Holding Tube (52) Storage part (53) Coil spring (55) Engaging member (55a) Top head (56) Recess (57) Disc spring

Claims (11)

It has a nesting die that molds the axial side surface of the molded product with a cylindrical core facing each other vertically, and has an upper die and a lower die that can be closed directly or with an intermediate die interposed therebetween. There are fitting holes for supporting the ends of the cylindrical cores set in the molds at the center of both types of nesting molds, and the cylindrical cores are provided in the lower mold side fitting holes. A support pin that fits into the lower end opening and locks the lower end, and the upper mold-side fitting hole is concentrically opposed to the support pin and locked to the upper end of the cylindrical core body A body presser is provided, and when both the upper and lower molds are closed, a cavity is formed on the outer periphery of the cylindrical core supported by the support pin and the core presser, and a molding material such as rubber is filled in the cavity. And a molding die that is molded integrally with the cylindrical core body,
The fitting hole in the upper mold side insert mold is provided with a seal ring that fits the outer periphery of the upper end of the cylindrical core body while maintaining a slight air permeability, and further, the cavity from the upper surface of the upper mold A molding die for a molded article with a cylindrical core, comprising: a molding material injection hole that communicates with the air; and air and molding material escape holes that lead from the cavity to the upper surface of the upper mold.   The molding of a molded article with a cylindrical core body according to claim 1, wherein the injection hole for the molding material and the escape hole for the upper die are provided at positions opposed to each other by 180 degrees across the axis of the cavity. Type.   A runner plate is detachably mounted on the upper surface of the upper mold. On the lower surface of the runner plate, a runner groove for injecting molding material and a groove for air and molding material are respectively provided. The molding die for a molded article with a cylindrical core body according to claim 1 or 2, wherein the molding die is formed so as to be continuous with the use hole.   2. A sealing member for receiving a core body, in which the lower end portion of the cylindrical core body is fitted with a slight air permeability, is provided in the fitting hole portion in the lower mold side insert mold. The shaping | molding die of the molded article with a cylindrical core body of any one of -3.   The support pin is displaceable upward in the axial direction, is biased downward by a return spring and is supported at a fixed position, and resists the biasing force of the return spring by a push-up means as appropriate during mold removal. The molding die for a molded article with a cylindrical core according to claim 4, which is provided so as to be pushed up.   The core body presser is supported so as to be displaceable in the axial direction within a predetermined size range, and is biased downward in the axial direction by the spring means, and in the mold closing state in which the cylindrical core body is supported, the biasing force of the spring means 6. The structure according to claim 1, wherein the cylindrical core body is pressed and displaced upward in the axial direction by opening the mold to disengage the upper end portion of the cylindrical core body from the fitting portion of the seal ring. A mold for forming the molded article with the cylindrical core according to the item.   The upper and lower molds are provided with a plurality of cavity constituent parts each including a nested mold, a support pin and a core presser that are opposed to each other, and injection holes for the molding material into the cavities in the respective cavity constituent parts are provided for injection of the injection device. The molding die for a molded article with a cylindrical core body according to any one of claims 1 to 6, which is arranged at an equal distance from the outlet.   The cavity component parts are arranged on the same circle centering on the injection port of the injection device, and the injection holes of the cavity component parts are arranged concentrically so as to be equidistant from the injection port. A mold for forming a molded article with a cylindrical core according to claim 7.   The molding die for a molded article with a cylindrical core according to claim 7 or 8, wherein the relief holes of the respective cavity constituent portions are continuous by escape grooves provided in the runner plate and communicate with the outside of the die side.   The cylinder according to claim 9, wherein the escape groove on the runner plate has a circular shape centered on the injection port of the injection device, and a protruding molding portion for forming a small convex portion is provided at the upper end of each escape hole. Mold for molded products with a core. The injection hole and the escape hole of each cavity component part are provided on the radiation which passes along the axial center of this cavity component part centering | focusing on the injection outlet of the said injection apparatus. Mold of the molded article with a cylindrical core as described.

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