JP6468811B2 - Elastomer mold and elastomer molded product - Google Patents

Description

  The present invention relates to an elastomer mold and a molded product thereof.

  Elastomers typified by rubber materials (hereinafter referred to as rubber materials) are molded into a desired shape by a molding die, and are used for various industrial materials, for example. In general, such a mold for rubber material has a cavity (molding space) corresponding to the shape of the molded product, a fluid material supply part for allowing the fluid rubber material to flow in, and a gate for communicating the fluid material supply part with the cavity. In the molding completed state, the molded product in the cavity and the cured rubber material (molded sprue) remaining in the fluid material supply part are connected by a thin part (communication burr) remaining in the gate part. Therefore, in order to take out (separate) the molded product, it was necessary to remove (cut) the communication burr.

  In a composite rubber molded product in which a rubber material is integrally vulcanized and molded on a core component made of a metal material, the applicant of the present application has applied the rubber material to the surface of the core component so that no burrs remain on the surface of the core component. A method has been proposed in which a burr connected by a thin part is actively formed, and this burr is cut and removed at the thin part after molding (Patent Document 1).

JP-A-9-117919

  However, although the technique of Patent Document 1 does not leave molding burrs on the surface of the core part, it still needs to remove the molding burrs (including the rubber material) after the molding is completed. Further, it cannot be applied to a rubber molded product having no core part.

  Accordingly, an object of the present invention is to obtain an elastomer mold and an elastomer molded product free from residual burrs in a state where molding is completed and the molded product is taken out from the mold.

  In the present invention, the gate in the conventional mold is outside the planar shape of the molded product and connects the cavity and the fluid material supply unit. If it is overlapped with a part of the burrs, it is based on the viewpoint that the burr removal work itself becomes unnecessary. On the other hand, if the gate is eliminated, a tear mark (a tear mark) is generated on the molded product, but the tear mark can be formed in a portion that does not affect the performance (function) of the molded product. .

An elastomer mold according to the present invention includes a cavity corresponding to a molded article of an elastomer material formed by a plurality of molds, and a flow formed in any one of the above molds that allow a flowable material to flow into the cavity. In the elastomer molding die having a material supply portion , the fluid material supply portion has a continuous groove portion having a closed curve along the planar shape of the cavity, and the diameter thereof is reduced toward the continuous groove portion. And a small-diameter neck formed at the boundary between the injection hole and the continuous groove, and the continuous groove and the cavity are viewed in a plan view in a mold-closed state. Are formed so as to communicate with each other via an inflow gap, and the neck portion connects the mold constituting the cavity and the fluid material supply portion. When the mold to be separated is separated, the separating force causes the molding sprue molded in the injection hole and the molding sprue molded in the continuous groove to be torn off at the neck, and into the continuous groove. The formed sprue is formed so as to remain on the mold side having the cavity . “Looking in a plane” means “looking from the direction along the mold opening and closing direction”. Closed curves include polygons that are greater than or equal to triangles.

  According to this mold, when the molding is completed, the molded product in the cavity and the molding sprue in the fluid material supply unit are connected by the “overlap portion (that is, the inflow gap)”. This connecting portion is torn when separating the plurality of molds. “Tear off” means that an external force is applied between the molded product and the molded sprue without using a blade to cause breakage. Of course, the tearing portion is set to a portion that does not affect the function (performance) of the molded product.

  In the preferred embodiment, the shape of the “overlap portion” is a shape along the planar shape of the molded product. For example, if the planar shape of the molded product is a circle, it can be shaped along the outer edge or inner edge of the circle. The “overlap portion” may be continuous or discontinuous.

  In one aspect of the present invention, the inflow gap can be formed on an extended surface (same surface) of the parting lines of a plurality of molds.

  The size of the inflow gap is preferably in the range of 0.02 mm to 0.15 mm. If it is less than 0.02 mm, the rubber material (elastomer material) in a fluid state does not flow into the cavity, and if it exceeds 0.15 mm, the mold and the molded product are separated (the molded product remains in the mold). When tearing from the molding sprue), the possibility of cracking in the molded article is increased.

  The molding die of the present invention can be used for molding a thermoplastic elastomer containing a thermoplastic resin in addition to various rubber materials.

  According to the present invention, it is possible to obtain an elastomer mold and an elastomer molded product in which the molded product is finished and the molded product is taken out from the mold, and no residual burrs are present in the molded product.

It is a perspective view which shows an example of the elastomer molded product shape | molded with the elastomer shaping | molding die by this invention. 1 is a longitudinal sectional view showing a first embodiment of an elastomer mold according to the present invention. FIG. 3 is an arrow view taken along line III-III in FIG. 2. FIG. 4 is a half cross-sectional perspective view showing a state of a rubber material in a state where molding by the molding die of FIGS. 2 and 3 is completed. It is a half cross-sectional perspective view which shows the die cutting state of the elastomer molded product. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the elastomer shaping | molding die by this invention. FIG. 7 is an arrow view taken along the line VII-VII in FIG. 6. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the elastomer shaping | molding die by this invention.

  1 to 5 show a first embodiment of an elastomer mold 100 and an elastomer molded product P to be molded according to the present invention. As shown in FIG. 1, the elastomer molded product P of this embodiment is a composite rubber product P in which a rubber material G is vulcanized and molded on a metal core part M. The composite rubber product P is an axially rotationally symmetric part in which the core part M forms a cylindrical shape and the rubber material G forms a perforated disk shape formed on the core part M. In the core part M, shaft holes M1 and M2 (FIG. 2) are formed above and below.

  As shown in FIG. 2, the elastomer mold 100 includes a guide mold (lower mold) 10, an intermediate mold 20, and an upper mold 30 in order from the bottom. The guide mold 10 has an upper guide mold 10A having an insertion hole 11 into which the core part M is inserted, and a lower boss 12 which is positioned at the bottom of the insertion hole 11 and is inserted into the shaft hole M2 of the core part M. It consists of a guide mold 10B. The upper guide mold 10A and the lower guide mold 10B can be configured integrally.

  The middle mold 20 has an inner taper hole 21, a cavity hole 22, and an upper surface release surface 23. The inner taper hole 21 is formed by a tapered inner taper surface whose diameter decreases as it goes upward in contact with the outer periphery of the upper end of the core part M inserted into the insertion hole 11 of the guide mold 10. The upper end surface of the core part M is a plane. The middle mold 20 and the guide mold (lower mold) 10 can be separated by a parting line PL1.

  The upper mold 30 has a positioning taper boss 31 inserted into the shaft hole M1 of the core part M and a lower surface release surface 32. The lower surface release surface 32 constitutes a parting line PL2 that comes into contact with and separates from the upper surface release surface 23 of the middle die 20. The cavity C for molding the rubber material G is an axially rotationally symmetric space formed by a space surrounded by the upper surface of the core part M, the inner surface of the cavity hole 22, the outer surface of the positioning taper boss 31 and the lower surface of the lower surface release surface 32. is there.

  The upper mold 30 is formed with a fluid material supply section (space, sprue) 33 that partially overlaps the cavity C when viewed in plan (viewed in the mold opening / closing direction (vertical direction in FIG. 2)). Has been. This fluid material supply section 33 has a trapezoidal all-circular groove (a continuous groove portion formed of a closed curve) 33a having a wide lower portion that opens on the lower surface release surface 32, and two injections communicating with the trapezoidal all-circular groove 33a. It consists of a taper hole (injection hole) 33b. FIG. 3 is a partially exaggerated drawing of the planar communication relationship between the trapezoidal full-circular groove 33a, the injection taper hole 33b, and the cavity C. The cross-sectional trapezoidal annular groove 33a is concentric with the taper boss 31, The width of the lower surface release surface 32 is a. The trapezoidal full-circular groove 33a and the cavity C communicate with each other in the inflow gap 35 having a width g at the upper edge of the cavity C. The inflow gap width g is 0.02 mm to 0.15 mm, more preferably 0.03 mm to 0.12 mm, depending on the size of the cavity C and the properties of the elastomer (fluidity). On the other hand, in this embodiment, two injection taper holes 33b are provided so as to communicate with the all-circular sectional trapezoidal all-annular groove 33a at two locations in the diametrical direction.

  The two injection taper holes 33b have the same shape and are reduced in diameter toward the trapezoidal full annular groove 33a, and the boundary portion with the cross sectional trapezoidal full annular groove 33a constitutes a small diameter neck part 33c.

  The molding procedure using the elastomer mold 100 is as follows. The core part M, which has been previously coated with an adhesive, is fitted into the insertion hole 11 of the guide mold 10 and the shaft hole M2 is fitted to the positioning boss 12 for positioning. Next, the middle mold 20 is overlaid on the guide mold 10 so that the outer periphery of the upper end of the core part M is brought into contact with the inner tapered hole 21, and the lower mold release surface 32 of the upper mold 30 is connected to the upper mold release surface 23 of the middle mold 20. The mold is closed by contact.

  When the fluid material is injected from the fluid material supply portion 33 (injection taper hole 33b) in the mold closed state, the material flows into the trapezoidal full annular groove 33a and then into the cavity C through the inflow gap 35. After the fluid material supply section 33 and the cavity C are filled with the fluid material, the fluid material is vulcanized and molded according to a conventional method, and the rubber material G corresponding to the shape of the cavity C is molded on the core part M. . In this molding completion state, the rubber material G cured in the cavity C and the molding sprue S cured in the fluid material supply portion 33 (the trapezoidal cross-section full annular groove 33a and the injection taper hole 33b) exist in the inflow gap 35. They are connected by a cured resin material (connection elastomer X) (FIG. 4). The size of the connection elastomer X (inflow gap 35) is exaggerated in FIGS. 3 and 4, but is actually about 0.1 mm as described above.

  When the upper die 30 and the middle die 20 are separated at the parting line PL2 in this molding completed state, the molding sprue S is first cut (teared) at the small-diameter neck portion 33c (FIG. 5). In other words, the size of the inflow gap 35 (total cross-sectional area) and the diameter of the neck part 33c (total cross-sectional area) so that the molded sprue S is cut (teared) at the neck part 33c and not cut by the connection elastomer X. Determine. In this cut state, the molding sprue remaining in the trapezoidal all-round groove 33a below the neck portion 33c remains on the upper surface release surface 23 as the product-side residual molding sprue S ′, and remains on the product-side residual molding. The sprue S ′ and the rubber material G are connected by the connection elastomer X in the inflow gap 35 (FIG. 5). In FIG. 5, a tear mark between the molding sprue S existing in the injection taper hole 33 b above the neck portion 33 c and the product-side residual molding sprue S ′ is indicated by S ″.

  Next, in a state where the guide mold (lower mold) 10 is separated from the middle mold 20 by the parting line PL1, the composite rubber product P having the rubber material G on the core part M is extruded as shown in FIG. When pushed down by 40, the connection elastomer X that has connected the product-side remaining molding sprue S ′ and the rubber material G (composite rubber product P) is torn off. Accordingly, a tear mark Y (FIG. 1) is generated on the outer peripheral edge of the upper surface of the rubber material G of the composite rubber product P. The tear mark Y (and the tear mark S ″) is provided in a portion that does not adversely affect the performance (for example, sealing performance) of the composite rubber product P.

In the first embodiment described above, the present invention is applied to the molding of a composite rubber product P composed of a metal core part M and a rubber material G. On the other hand, FIG. 6, FIG. 7 has shown 2nd Embodiment which applied this invention to shaping | molding of a simple disk shaped rubber product (rubber molded product which does not have a core component). In this embodiment, the elastomer mold 100 ′ includes a lower mold 10 ′, a middle mold 20 ′, and an upper mold 30 ′. The lower mold 10 ′ and the middle mold 20 ′ can be separated by a parting line PL1, and the middle mold 20 ′. The upper mold 30 'can be separated by a parting line PL2. A molding space 26 is formed by the upper surface 14 of the lower mold 10 ′, the molding hole 25 of the middle mold 20 ′, and the lower mold release surface 32 (parting line PL2) of the upper mold 30 ′. The upper mold 30 'is formed with a fluid material supply portion 33 comprising a trapezoidal full annular groove 33a and a taper injection hole 33b similar to those in the first embodiment, and a trapezoidal full annular groove 33a and a molding space 26 are formed. The inflow gap 35 communicates.

  According to this embodiment, after the molding of the rubber material in the molding space 26 is completed, by removing the upper mold 30 ′ from the middle mold 20 ′, a separate burr cutting operation is performed as in the first embodiment. It is not necessary to obtain a disk-shaped rubber molded product that leaves a tear mark of the connecting elastomer on the periphery of the upper surface in FIG. 6 of the molded product molded in the molding space 26. Subsequently, the molded product can be taken out by extruding the molded product from the middle mold 20 ′ with the lower mold 10 ′ removed from the middle mold 20 ′.

FIG. 8 shows a configuration example of an elastomer mold 100 ″ when the molded product is an annular member. The difference from FIG. 7 is that the middle mold 20 ″ has a trapezoidal cross section of an upper mold 30 ″. An annular groove 27 is formed by shifting the center from the groove 33a, and is formed by the annular groove 27, the upper surface 11 of the lower mold 10 ", and the lower mold release surface 32 (parting line PL2) of the upper mold 30 '. The space 28 is formed. In plan view, the inner edge of the annular groove 27 and the outer edge of the trapezoidal full-circular groove 33a are slightly in communication with each other (only the gap g in the first embodiment).

  In the above embodiment, the inflow gap for communicating the cavity and the fluid material supply unit is formed on the extended surface (same surface) of the parting lines of the plurality of molds, but the cavity and the fluid material supply unit are flat. As long as they overlap with each other, they do not necessarily exist on the extended surface of the parting line.

  In the above embodiment, the planar shape of the communication groove 33a communicating with the cavity C through the inflow gap 35 is circular. However, the planar shape of the communication groove can be changed according to the planar shape of the cavity C. It can also be discontinuous.

M Core parts M1 M2 Shaft hole G Rubber material P Composite rubber product (elastomer molded product)
C cavity Y tear mark S molding sprue S 'product side residual molding sprue PL1 PL2 parting line X connection elastomer 100 100'100 "elastomer molding die 10 guide die 10A upper guide die 10B lower guide die 11 insertion hole 12 Positioning boss 20 20 ′ Middle mold 21 Inner taper hole 22 Cavity hole 23 Upper surface release surface 24 26 28 Molding space 30 30 ′ Upper mold 31 Positioning taper boss 32 Lower surface release surface 33 Fluid material supply portion 33a Continuous groove)
33b Injection taper hole (injection hole)
33c Neck part 35 Inflow gap 40 Extrusion rod

Claims (4)

Elastomer mold having a cavity corresponding to a molded article of elastomer material formed by a plurality of molds, and a fluid material supply part formed in any one of the above molds for allowing a fluid material to flow into the cavity In
The fluid material supply unit includes a continuous groove portion having a closed curve along the planar shape of the cavity, a plurality of injection holes which are reduced in diameter toward the continuous groove portion and supply the fluid material to the continuous groove portion, and the injection A small-diameter neck formed at the boundary between the hole and the continuous groove,
The continuous groove and the cavity are formed so as to overlap each other in a plan view in a closed state and communicate with each other through an inflow gap, and the neck constitutes the cavity. When the mold and the mold having the fluid material supply portion are separated, due to the separation force, the molding sprue molded in the injection hole and the molding sprue molded in the continuous groove portion are formed in the neck portion. An elastomer mold, which is formed so that a molding sprue that is torn and molded in the continuous groove portion remains on the mold side having the cavity.   2. The elastomer mold according to claim 1, wherein the overlap portion has a shape along a planar shape of a molded product.   The elastomer mold according to claim 1 or 2, wherein the inflow gap is located on an extended surface of a parting line of a plurality of molds.   The elastomer mold according to any one of claims 1 to 3, wherein the inflow gap has a size in a range of 0.02 mm to 0.15 mm.

Images