JP3883180B2 - Mold for bead molding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bead molding die used in a molding method of a bead foam molding suitable for a sun visor core in an automotive sun visor, and in particular, by devising a steam supply system, The present invention relates to a bead molding die that can reduce the frequency of maintenance, reduce the frequency of maintenance, and obtain a good product appearance.
[0002]
[Prior art]
Usually, an automobile sun visor 1 having a sunshade function is installed obliquely above the passengers in the driver's seat and the auxiliary seat, as shown in FIG. 7, and this automobile sun visor 1 has a desired light-shielding area. The sun visor body 2 is rotatably supported by a rotation shaft 1a, and the bracket 1b to which the rotation shaft 1a is attached is fixed to the ceiling side, and the rotation shaft 1a is rotated around the axis with respect to the bracket 1b. Thus, the sun visor body 2 is supported so as to be rotatable in the vertical direction and the horizontal direction.
[0003]
By the way, the sun visor main body 2 is configured by encapsulating the outer surface of the sun visor core 3 with a sun visor skin 4, and in particular, as a material used for the sun visor core 3, a bead foam molded body that is lightweight and excellent in impact resistance. Tend to be used frequently.
[0004]
FIG. 8 shows a bead molding die 5 used for molding the sun visor core 3 using polypropylene beads as a material. The bead molding die 5 is a split mold 5a that can be opened and closed with each other. , 5b, and a foam bead material P is filled from a bead supply feeder (not shown) into a cavity C defined by both molds 5a, 5b. Steam is supplied from the side chamber 6b to the upper chamber 6a as shown by an arrow, and as shown in FIG. 9, the vent C is embedded in the cavity C through the vent hole 7a of the vent piece 7 embedded in the molds 5a and 5b. By supplying steam heated to a predetermined temperature, a foaming reaction of the expandable bead material P is induced, and the sun visor core 3 along the cavity C shape is formed.
[0005]
[Problems to be solved by the invention]
However, in the conventional bead molding die 5, the steam supply system is such that a steam flow is set from the lower chamber 6 b to the upper chamber 6 a, and steam enters the cavity C through the vent hole 7 a of the vent piece 7. Therefore, the vent hole 7a of the vent piece 7 is easily clogged, and there is room for improvement in terms of stable supply of steam.
[0006]
Furthermore, since the traces of the vent holes 7a of the vent piece 7 are formed as irregularities after the molding of the sun visor core 3, it is necessary to rework the irregularities, and clogging of the vent holes 7a occurs. At the same time, it has been pointed out that there is a problem that the maintenance work of the metal mold 5 must be performed frequently.
[0007]
In addition, because of the structure of the bead molding die 5, a vent hole for receiving the vent piece 7 is opened in each of the split molds 5 a and 5 b, and the vent piece 7 is buried and fixed by driving into the receiving hole. It has been pointed out simultaneously that the fixing work of the piece 7 is troublesome and causes a long processing time for the mold.
[0008]
Further, the curved surface of the sun visor core 3 is stretched by the sun visor skin 4 when the skin material is applied, and the unevenness of the surface of the sun visor core 3 appears remarkably on the surface. This is also a factor for reducing the supply efficiency of steam during bead molding.
[0009]
This invention was made in view of such circumstances, and is a bead molding die that can mold a bead foam molded body encapsulated in the skin into a required shape like a sun visor core in an automobile sun visor. , aims to look appearance and touch feeling of the product is good, and can reduce the mold costs of the bead molding die, moreover, such can be reduced maintenance frequency, to provide a practical beads mold And
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a split mold that can be opened and clamped to each other to form a cavity having a desired shape, a bead supply feeder that supplies an expandable bead material into the cavity, and an expandability A bead molding die having a steam supply system for supplying steam into a cavity in order to cause foaming of the bead material, wherein the split die is supplied to the parting surface along the outer peripheral edge of the cavity. The opening of the steam hole which communicates with the system faces, and a steam injection plate is provided on the parting surface between the divided molds .
[0013]
Here, the foamable bead material may be appropriately selected from polypropylene (PP) bead material, polyethylene (PE) bead material, polystyrene (PS) bead material, etc., but in consideration of moldability and cost, polypropylene ( PP) bead material is preferred.
[0014]
The bead molding mold is composed of split molds that can be mutually opened and clamped, and each split mold includes a chamber block that includes a chamber to which steam from the outside is supplied. In addition, the chamber block is provided with a bead supply feeder that can supply the expandable bead material in the cavity on one side of the split mold, and steam supply is performed for the foaming reaction of the expandable bead material in the cavity. A cooling system for cooling the system and the bead compact after the foaming reaction is provided.
[0015]
Furthermore, the steam supply system has a plurality of steam holes facing each part line surface of the upper mold and the lower mold, and the steam holes communicating with the chambers are connected to the parting line surface. Steam is supplied and a minute clearance of about 0.2 to 0.4 mm is set on the parting surface, whereby steam is introduced into and discharged from the entire peripheral edge of the cavity.
[0016]
As apparent from the above configuration, according to the present invention, the steam is supplied into the cavity through the minute clearance of the parting surface along the outer peripheral edge of the cavity. By changing from to a linear groove, steam can be supplied stably.
[0017]
In addition, since the V-groove at the peripheral edge of the cavity does not appear as irregularities on the product surface, it is possible to eliminate the work of correcting the irregularities of the vapor hole traces and eliminate clogging of the vapor holes, thus maintaining the mold for bead molding. The time can be extended from 3 months to 6 months, and the maintenance frequency can be halved. Furthermore, since the process of driving the vent piece into the mold can be eliminated, the mold process can be simplified.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a bead molding die according to the present invention will be described in detail with reference to the accompanying drawings.
[0019]
FIG. 1 is a front view showing an automobile sun visor using a sun visor core manufactured by using a bead molding die according to the present invention, FIG. 2 is a sectional view showing the configuration of the automobile sun visor, and FIG. 4 is an explanatory view showing a reference example of the bead molding die according to FIG. 4, FIG. 4 is a cross-sectional view showing a state of supplying steam in the molding die, and FIG. 5 is a configuration of an upper die and a lower die of the molding die. FIG. 6 is an explanatory view showing a bead molding die according to the present invention .
[0020]
1 and 2, an automobile sun visor 10 is installed obliquely above a driver's seat, and a sun visor body 11 having a sunshade function is rotatably supported by a turning shaft 12. A bracket 13 to be inserted and held is fixed to the ceiling surface 14. An auxiliary knob 15 provided at the other end opposite to the rotation shaft 12 is engaged with a holder 16 attached to the ceiling surface 14, and the sun visor body 11 is supported by two points of the rotation shaft 12 and the auxiliary knob 15.
[0021]
Furthermore, the sun visor body 11 is lightweight and has an appropriate shape retaining property, and preferably has an excellent shock absorbing function when the head of an occupant collides with it. The outer surface of the sun visor core 11a made of the bead foam molded body is encapsulated with a sun visor skin 11b made of a vinyl chloride sheet or the like.
[0022]
In this embodiment, a 20-fold expanded PP bead foam molded body is used as the bead foam molded body. However, the expansion ratio may be variably adjusted or replaced with a polyethylene bead foam molded body. As the sun visor skin 11b, in addition to the vinyl chloride sheet, it is also possible to use a laminate of a vinyl chloride sheet on the back of the nonwoven fabric or a cloth.
[0023]
The present invention relates to the structure of a bead molding die used when molding the sun visor core 11a in the automobile sun visor 10. The product surface of the sun visor 10 is smooth, has a good appearance, and has a good feel. When the sun visor skin 11b is attached to the surface of the sun visor core 11a with an appropriate tension, the operation of attaching the sun visor skin 11b can be performed smoothly.
[0024]
FIG. 3 shows a reference example of the bead molding die 20 according to the present invention. The bead molding die 20 has a split die (described below as a lower die 30 and an upper die 40), and is opened. It is provided so that mold clamping is possible.
[0025]
More specifically, as shown in FIGS. 3 to 5, the lower mold 30 has a chamber block 33 having a chamber 32 attached to the upper surface of the lower table 31, and the lower mold 30 is mounted on the chamber block 33. Are placed, and the lower mold 30 is provided with steam holes 34 having a diameter of 9 mm at approximately ten pitch intervals at the lower die 30.
[0026]
On the other hand, for the upper mold 40, a chamber block 43 having a chamber 42 is attached to the lower surface of the upper table 41. The upper mold 40 is connected to the lower surface of the chamber block 43 and communicates with the chamber 42. Also in the mold 40, the vapor holes 44 are provided at 10 places each having a diameter of 9 mm. The upper die 40 is moved up and down by a predetermined stroke by an elevating cylinder 41a fixed to the upper table 41.
[0027]
Further, a bead supply feeder 50 for supplying PP foam particles is attached to the upper chamber block 43 and the upper mold 40 so that the opening faces the cavity C, respectively.
[0028]
In the above configuration , the lower mold 30 and the upper mold 40 are provided with steam holes 34, 44. As shown in FIGS. 4 and 5, the steam holes 34, 44 are connected to the lower mold 30 and the upper mold 40, respectively. It is set so as to face the parting surface 60 of the mold 40.
[0029]
Therefore, in the actual bead forming process, the upper die 40 is lowered by the operation of the lifting cylinder 41a, and the upper die 40 is clamped with respect to the lower die 30. The clearance at the parting surface 60 (indicated by d in FIG. 4) is adjusted to be 0.2 mm.
[0030]
After the upper and lower molds 30 and 40 are clamped, PP foam bead material P is supplied into the cavity C through the bead supply feeder 50, and then steam is generated from the lower chamber 32 through the vapor holes 34 of the lower mold 30. Since a small clearance d of 0.2 mm is set on the parting surfaces 60 of the upper and lower molds 30 and 40, the clearance is supplied to the parting surface 60. Steam is supplied. Similarly, the steam is effectively introduced into the cavity C from the linear introduction portion along the peripheral edge of the cavity C through the vapor hole 44 of the upper mold 40 communicating with the upper chamber 42, so that the steam is effectively introduced into the cavity C. The bead foam molding is smoothly foamed by being introduced into the inside.
[0031]
Further, as shown in FIG. 6, a brass steam injection plate 70 may be provided in a portion corresponding to the parting surface 60 of the upper and lower molds 30 and 40. The steam injection plate 70 is composed of an upper plate 70a attached to the mold surface of the upper mold 40 and a lower plate 70b positioned with a small clearance from the upper plate 70a. The inlet hole 71 for supplying steam from the steam hole 34 of the lower mold 30 is opened, and the steam fed from the inlet hole 71 into the steam injection plate 70 is supplied into the cavity C from the outlet hole 72.
[0032]
Further, the exit hole 72 portion of the steam injection plate 70 has entered the cavity C and interferes with the bead foam molded product during the demolding operation of the bead foam molded product, but if the bead supply feeder 50 has an ejector function. By avoiding interference with the steam injection plate 70, the bead foam molded product can be removed smoothly.
[0033]
When the injection plate 70 is used, there is an advantage that it is not necessary to manage the clearance of the parting surface 60 in the upper and lower molds 30 and 40 and the press control can be simplified.
[0034]
Thus, according to the bead molding die 20 according to the present invention, the conventional vent piece by the point hole is abolished, so there is no clogging of the steam hole, and the maintenance time can be extended from 3 months to 6 months. In addition, the beads can be formed smoothly.
[0035]
Furthermore, since no traces of vapor holes remain, it is not necessary to finish the product surface, and it is not necessary to drive the vent piece into the mold, so that the mold cost can be reduced.
[0036]
In addition, when applied to the sun visor 10 for automobiles, traces such as vent holes do not remain on the outer surface of the sun visor core 11a made of a bead foam molded product, so that a thin sun visor skin 11b can be used. There is an advantage that the degree of freedom of material can be increased and the cost can be reduced.
[0037]
【The invention's effect】
As described above, according to the bead molding die according to the present invention, a minute clearance is set on the parting surface of the split die, and a steam hole and a steam injection plate are provided on the parting surface, and the outer peripheral edge of the cavity Since steam is supplied from the entire length of the steam, or from a part of it, it is not a point hole, and there is no clogging of the steam hole as in the conventional vent piece structure. In addition to reducing the frequency of maintenance of the mold, it is possible to eliminate the mold processing for providing the steam holes and to reduce the mold cost of the mold for molding.
[0038]
Furthermore, since steam is supplied into the cavity from a part other than the product surface, such as the peripheral edge of the cavity, it is possible to eliminate the process of repairing irregularities that are traces of vapor holes as in the past, and a good surface state can be obtained. When encapsulating the outer surface of the foamed molded article with a skin, it has an effect that the degree of freedom of material can be improved, for example, a thin skin can be used.
[Brief description of the drawings]
FIG. 1 is a front view showing an automobile sun visor using a sun visor core manufactured using a bead molding die according to the present invention.
FIG. 2 is a sectional view taken along line II-II in FIG.
FIG. 3 is an explanatory view showing a reference example of a bead molding die according to the present invention.
4 is a cross-sectional view showing a state when steam is supplied in the bead molding die shown in FIG. 3; FIG.
5 is a schematic view of an upper mold and a lower mold in the bead molding mold shown in FIG. 3. FIG.
FIG. 6 is an explanatory view showing a bead molding die according to the present invention .
FIG. 7 is a front view showing a conventional automobile sun visor.
FIG. 8 is an explanatory diagram showing a bead molding process of a sun visor core in a conventional automobile sun visor.
FIG. 9 is an explanatory view showing a vent piece in a conventional bead forming process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Automobile sun visor 11 Sun visor main body 11a Sun visor core 11b Sun visor skin 20 Bead mold 30 Lower mold 31 Lower table 32 Chamber 33 Chamber block 34 Vapor hole 40 Upper mold 41 Upper table 41 Chamber 43 Chamber block 44 Vapor hole 50 Beads Supply feeder 60 Parting surface 70 Steam injection plate C Cavity

Claims (1)

Separately moldable molds (30, 40) capable of forming a cavity (C) of a desired shape and a bead supply feeder (50) for supplying an expandable bead material (P) into the cavity (C). ) And a bead molding die having a steam supply system for supplying steam into the cavity (C) in order to cause foaming of the expandable bead material (P),
In the split mold (30, 40), the opening of the steam hole (34, 44) communicating with the steam supply system faces the parting surface (60) along the outer peripheral edge of the cavity (C) , and the split mold A bead molding die characterized in that a steam injection plate (70) is provided on a parting surface (60) between the die (30, 40).

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