JP5435893B2 - Mold for foam molding and foam molding method - Google Patents

Description

  The present invention relates to a mold for manufacturing a resin foam molded article such as a seat pad, and more particularly to a mold having a packing provided on a mating surface between molds. The present invention also relates to a foam molding method using this mold.

  Foam molding such as flexible polyurethane foam for automobile seat pads is performed by foaming a urethane stock solution in a mold. Normally, this mold includes an upper mold and a lower mold.

  I. Japanese Utility Model Laid-Open No. 62-185015 describes that packing is provided on the mating surface of the upper mold and the lower mold.

  FIG. 5 is a cross-sectional view of the packing portion of Japanese Utility Model Application Laid-Open No. 62-185015. A groove 42 having a circular arc cross section is provided on the mating surface 41 of the lower mold 40, and a lower portion 51 of the packing 50 is fitted in the groove 42.

The upper part of the packing is a plate-like portion 52 that protrudes from the mating surface 41 and spreads along the mating surface 41. A convex portion 53 is provided on a part of the plate-like portion 52.
II. Japanese Utility Model Laid-Open No. 6-42130 also describes that the cross-sectional shape of the groove on the mating surface of the lower mold is an arc.

FIG. 6 is a cross-sectional view showing the vicinity of the mating surface of the lower die of this actual flat 6-42130. A groove 62 having a circular arc cross section is provided on the mating surface of the lower die 61, and a packing 63 having a circular cross section is fitted in the groove 62. The upper side of the packing protrudes from the mating surface of the lower mold 61.
Japanese Utility Model Sho 62-185015 6-42130

  The plate-like portion 52 of the actual Japanese Utility Model Publication No. 62-185015 is separated (retreated) from the edge portion 44 on the cavity 43 side. Therefore, when the mold is clamped, a gap exists on the mating surface on the cavity 43 side of the plate-like portion 52.

  When the seat pad is molded using such a mold, if there is a slightly low airtight portion between the upper mold and the packing 50, urethane enters the mating surface and burrs are generated.

  The burrs are removed by the worker after demolding, which is a cause of labor and cost for manufacturing a molded product such as a seat pad.

  In FIG. 5, the groove 42 has a substantially circular cross-sectional shape. Therefore, if the groove 42 is brought too close to the cavity 43, the thickness of the lower mold 40 between the groove 42 and the cavity 43 is increased. It becomes smaller and lacks strength. Moreover, it is necessary to increase machining accuracy. Therefore, it is necessary to separate the groove 42 from the cavity 43 to some extent, and as a result, the distance from the plate-like portion 52 to the cavity 43 is large.

  Further, the groove portion 62 of the actual open flat 6-42130 and the packing 63 fitted in the groove portion 62 are also separated from the cavity-side edge portion of the mating surface of the lower mold 61.

  In particular, since this packing 63 does not have a portion corresponding to the plate-like portion 52 in the above-mentioned Japanese Utility Model Publication No. 62-185015, there is a larger gap on the cavity side than the packing 63 on the mating surface. .

  Therefore, when the seat pad is molded using the actual dies 6-42130, a larger amount of urethane enters the mating surfaces than when the actual dies 62-185015 are used. Will occur.

  The present invention solves the above-mentioned conventional problems, and provides a mold for foam molding that can sufficiently prevent the occurrence of burrs in a molded product, and a foam molding method using this mold. With the goal.

The mold for foam molding according to claim 1 is provided with a packing extending along a cavity of the mold on a mating surface between the molds, and the packing is held in a groove provided on the mating surface. The foam molding mold is a foam molding mold having a width of 0.1 to 10 mm closer to the cavity than the groove of the mating surfaces, and the groove includes a deep groove portion and The gasket includes a shallow groove portion that is continuous with the deep groove portion, and the packing includes a base portion that is fitted into the deep groove portion, and an overhang portion that is continuous with the base portion and engages with the shallow groove portion. It is characterized by .

Mold for foam molding of 請 Motomeko 2, according to claim 1, wherein the shallow groove portion, characterized in that provided on the cavity side than at least the deep grooves.

A mold for foam molding according to a third aspect is characterized in that, in the first or second aspect, the width is 0.1 to 5 mm .

The foam molding method of the present invention (Claim 4 ) uses the foam molding die according to any one of Claims 1 to 3 .

According to a fifth aspect of the present invention, the foam molding method according to the fourth aspect is characterized in that the seat pad is foam-molded.

  In the mold and the foam molding method of the present invention, the width of the cavity side of the mating surface is 0.1 to 10 mm smaller than the groove, and the packing is held in the groove. The distance to the packing is small. Therefore, when a deformable material such as urethane enters between the mating surfaces at the time of foam molding, the gas pressure on the mating surfaces increases, and the molding material such as urethane is prevented from entering the mating surfaces. Thereby, generation | occurrence | production of a burr | flash is prevented. Further, the deterioration of the packing due to the contact of urethane or the like with the packing is also prevented.

In the mold according to the first aspect , since the groove has a deep groove portion, and the base portion of the packing is sufficiently deeply fitted into the deep groove portion, the mounting strength of the packing is high.

In the mold according to claim 2 , since the shallow groove portion is provided at least on the cavity side with respect to the deep groove portion, the deep groove portion can be obtained even if the width of the cavity side of the mating surface is sufficiently smaller than the groove. The distance from the cavity to the cavity can be increased. For this reason, the mold strength in the cavity vicinity portion of the mating surface can be increased. Further, the processing accuracy of the groove is relaxed.

Hereinafter, embodiments will be described with reference to the drawings. Figure 1 (a) is a seat back pad mold longitudinal cross-sectional view of a right half of that according to the embodiment, FIG. 1 (b) is an enlarged view of a B portion of FIG. 1 (a), second FIG. 2 (a) is an enlarged view of part B just before clamping, and FIG. 2 (b) is an explanatory diagram of dimensions of the packing part.

  A mold 1 according to this embodiment is for molding a seat back pad of an automobile, and includes an upper mold 2, a lower mold 3, and a core 4 held by the upper mold 2. . A packing 5 is provided on the mating surface of the upper mold 2 and the lower mold 3.

  As clearly shown in FIG. 2, in this embodiment, a groove 6 for packing attachment extends on the mating surface 3 a of the lower mold 3 so as to surround the cavity 7.

  The groove 6 includes a deep groove portion 6a that is deeply recessed from the mating surface 3a, and a shallow groove portion 6b that is located on the cavity 7 side of the deep groove portion 6a and that is continuous with the deep groove portion 6a. The shallow groove portion 6b is provided in a rectangular cross-sectional shape having substantially the same depth in the width direction (left-right direction in FIG. 2A) and the longitudinal direction of the groove 6 (perpendicular to the paper surface in FIG. 2A). ing.

  A portion of the lower mold 3 closer to the cavity 7 than the shallow groove 6b is an inner edge 3b (FIG. 2 (a)).

  The packing 5 includes a base portion 5a inserted into the deep groove portion 6a and an overhang portion 5b connected to the base portion 5a and engaged with the shallow groove portion 6b. The packing 5 is attached to the lower mold 3 by fitting the base 5a into the deep groove 6a. A side surface of the base portion 5a is provided with a sawtooth cross-sectional shape portion 5d so that the base portion 5a can be easily inserted into the deep groove portion 6a and cannot be easily removed from the deep groove portion 6a. The lower surface of the overhang portion 5b is in contact with the bottom surface of the shallow groove portion 6b.

  The packing 5 is made of rubber or elastomer (preferably, an olefin-based elastomer, silicone rubber, fluororubber or the like having high elasticity).

  The packing 5 has a protrusion 5c protruding from the mating surface 3a. The upper surface of the protrusion 5c is a substantially horizontal plane. However, the upper surface of the packing 5 may have a triangular cross-sectional shape that is highest at the center side and gradually decreases in height from the cavity side to the opposite side, and other cross-sectional shapes such as an arc shape and a trapezoidal shape. May be.

  The mating surface 2a of the upper mold 2 is a flat surface.

  In FIG. 2 (b), the width a of the inner edge 3b on the cavity 7 side of the groove 6 in the mating surface 3a is 0.1 to 10 mm, preferably 0.1 to 5 mm, particularly preferably 2 to 4 mm. It is.

  The depth b of the shallow groove portion 6b is preferably about 1 to 10 mm, particularly about 2 to 5 mm. If it is 2 mm or more, the overhanging portion 5b fits well into the shallow groove portion 6b. If it is 5 mm or less, the strength of the inner edge 3b (FIG. 2 (b)) is high, and the mold is hardly damaged.

  The ratio (a / b) between the width a and the depth b is preferably about 0.01 to 10, particularly about 0.4 to 2.

  The width c of the shallow groove portion 6b in the mating surface direction (that is, the dimension in the direction orthogonal to the groove longitudinal direction) is preferably about 1 to 13 mm, particularly about 2 to 6 mm. When it is 2 mm or more, the sealing property is good.

  The width d (that is, the dimension in the direction perpendicular to the groove longitudinal direction) of the deep groove 6a in the mating surface direction is preferably about 3 to 20 mm, particularly about 6 to 12 mm. The depth e of the deep groove 6a is preferably about 5 to 25 mm, particularly about 10 to 15 mm.

  In a state before mold clamping, the protruding height h of the packing 5 from the mating surface 3a is preferably about 0.1 to 10 mm, particularly about 0.5 to 2 mm. Further, it is preferable to compress and deform the projecting height by clamping so that the protruding height is 99% or less, particularly about 60 to 95% of the original height.

  In order to perform molding using the mold 1 configured as described above, a mold release agent is applied to the inner surface of the mold 1 in the mold open state, and then a urethane stock solution is supplied into the cavity 7 of the lower mold 3 to clamp the mold. And heat to foam urethane.

  When the urethane is sufficiently foamed to fill the cavity 7 with the foamed urethane and then the mold is opened after a predetermined time has elapsed, a seat back pad molded product made of polyurethane foam is obtained.

  In this embodiment, since the width a of the inner edge 3b of the mating surface 3a is as small as 0.1 to 10 mm, the distance from the cavity 7 to the packing 5 is small when the mold is clamped. Therefore, when urethane tries to penetrate between the mating surfaces 2a and 3a at the time of foam molding, the gas pressure on the mating surface increases, and the urethane is prevented from entering the mating surface. In this way, no or almost no urethane penetrates the mating surface of the upper mold 2 and the lower mold 3, so no burrs are generated. Moreover, since urethane does not contact the packing 5, the deterioration of the packing 5 is also prevented.

  In this embodiment, since the groove 6 has a deep groove portion 6a, and the base portion 5a of the packing 5 is deeply fitted to the deep groove portion 6a, the mounting strength of the packing 5 is high.

  In this embodiment, since the cavity 6 side of the groove 6 is the shallow groove portion 6b, the strength of the lower die 3 in the vicinity of the inner edge portion 3b is high even if the width a of the inner edge portion 3b of the lower die 3 is small. Further, the processing accuracy when the grooves 6 are formed by cutting or the like is eased.

  Another embodiment will be described with reference to FIGS.

  In FIG. 3, the groove 10 provided in the lower mold 3A has a deep groove portion 10a and a shallow groove portion 10b provided on the cavity 7 side of the deep groove portion 10a. The deep groove portion 10a has a wider bottom side, and a step portion 10c is formed in the middle of the deep groove portion 10a in the depth direction. The shallow groove portion 10b becomes shallower as the distance from the deep groove portion 10a increases.

  The packing 11 has a base portion 11a and an overhang portion 11b that projects from the base portion 11a to the cavity 7 side. The lower surface of the protruding portion 11b is in contact with the bottom surface of the shallow groove portion 10b. The base portion 11a of the packing 11 is provided with a fin-like lip portion 11d, and the lip portion 11d is engaged with the step portion 10c to prevent the packing 11 from coming out.

  The packing 11 has a protrusion 11c protruding from the mating surface 3a. The upper surface of the protrusion 11c is a substantially horizontal plane. However, the upper surface of the packing 11 may have a triangular cross-sectional shape that is highest at the center side and gradually decreases in height from the center side toward the cavity side and the opposite side, and other cross-sectional shapes such as an arc shape and a trapezoidal shape. May be.

  The mating surface 2a of the upper mold 2A is a flat surface.

  In FIG. 4, the groove 14 provided in the lower mold 3B has a deep groove portion 14a and a shallow groove portion 14b provided on the cavity 7 side of the inlet portion of the deep groove portion 14a. The deep groove portion 14a is widened in a circular cross section on the bottom side, and a downward slope 14c is formed in the middle of the depth direction of the deep groove portion 14a. The cross-sectional shape of the shallow groove portion 14b is a quadrant that is concavely curved.

  The packing 15 includes a base portion 15a and an overhang portion 15b projecting from the base portion 15a to the cavity 7 side.

  The upper surface of the packing 15 is a protrusion 15c that protrudes from the mating surface 3a. The protrusion 15c has a substantially semicircular arc cross-sectional shape that is highest at the center in the width direction and gradually decreases toward both ends. A protruding portion 15d is provided on the side surface of the base portion 15a of the packing 15 in order to facilitate insertion into the deep groove portion 14a and to prevent removal from the deep groove portion 14a. The protruding portion 15d is engaged with the downward inclined surface 14c, thereby preventing the packing 15 from coming off.

  On the mating surface 2 a of the upper mold 2, a concave groove 16 having a substantially semicircular cross-sectional shape is provided at a position facing the protruding portion 15 c of the packing 15. The entrance width of the concave groove 16 is the same as the width at the base of the protrusion 15c (level of the mating surface 3a). The concave groove 16 is shallower than the protruding height of the protruding portion 15c from the mating surface 3a, and is configured so that the packing 15 can be sufficiently pressed during mold clamping.

  Also in these molds of FIGS. 3 and 4, the width of the inner edge of the mating surface 3a closer to the cavity 7 than the grooves 10 and 14 is 0.1 to 10 mm, preferably 0.1 to 5 mm. Especially preferably, it is 2-4 mm. The depth of the deepest portion of the shallow groove portions 10b and 14b is preferably about 1 to 10 mm, particularly about 2 to 5 mm. The width in the mating surface direction of the shallow groove portions 10b and 14b is preferably about 1 to 13 mm, particularly about 2 to 6 mm. In the state before mold clamping, it is preferable that the protrusion height h of the packings 11 and 15 from the mating surface 3a is about 0.1 to 10 mm, particularly about 0.5 to 2 mm. Further, it is preferable to compress and deform the projecting height by clamping so that the protruding height is 99% or less, particularly about 70 to 95% of the original height.

  When foam molding of the seat pad is performed using the molds shown in FIGS. 3 and 4, urethane is prevented from entering between the mating surfaces 2a and 3a, and burrs are prevented from being generated. Further, the deterioration of the packing is prevented, and the processing accuracy of the grooves 10 and 14 is reduced.

  Although the seat back pad is formed in the above embodiment, the seat cushion pad can be formed in the same manner. The present invention can be applied to molding of a resin foam molded product other than a seat pad.

  The present invention can be applied not only to the mating surface of the upper mold and the lower mold but also to all the mating points of the molds such as the upper mold and the core and the lower mold and the core.

(A) The figure is a longitudinal cross-sectional view of the right half of the mold for forming a seat back pad according to the embodiment, and (b) is an enlarged view of a portion B in (a). It is the B section enlarged view just before the mold clamping of the metal mold | die of FIG. It is a partial cross section figure of the metal mold | die which concerns on another embodiment. It is a partial cross section figure of the metal mold | die which concerns on another embodiment. It is sectional drawing explaining the structure of the packing part of the metal mold | die which concerns on a prior art example. It is sectional drawing explaining the structure of the packing part of the metal mold | die which concerns on another prior art example.

1 Mold 2, 2A, 2B Upper mold 3, 3A, 3B Lower mold 4 Core 5, 11, 15 Packing 6, 10, 14 Groove 6a, 10a, 14a Deep groove 6b, 10b, 14b Shallow groove 7, 43 Cavity

Claims (5)

A packing extending along the mold cavity is provided on the mating surface between the molds,
The packing is a mold for foam molding held in a groove provided on the mating surface.
A mold for foam molding, wherein the width of the cavity side of the mating surface is 0.1 to 10 mm from the groove,
The groove includes a deep groove portion and a shallow groove portion connected to the deep groove portion,
The packing has a base part fitted in the deep groove part, and an overhang part that is connected to the base part and engages with the shallow groove part.   2. The mold for foam molding according to claim 1, wherein the shallow groove portion is provided at least on the cavity side with respect to the deep groove portion. 3. The mold for foam molding according to claim 1, wherein the width is 0.1 to 5 mm .   A foam molding method using the mold for foam molding according to any one of claims 1 to 3.   5. The foam molding method according to claim 4, wherein the seat pad is foam-molded.

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