JP3664825B2 - Blow molding die and blow molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blow molding die and a blow molding method that can efficiently produce a blow molded product integrally molded with a decorative skin, in particular, without causing deformation.
[0002]
[Prior art]
As an example of a blow molded product having a decorative skin, FIG. 7 shows a seat frame 4 used for a rear seat back of a vehicle seat. The seat frame 4 shown in the figure is a substantially rectangular plate, and one side edge is notched in the lower half in order to avoid interference with the wheel housing. The rear surface of the seat frame 4 leaves the entire outer periphery as a frame portion 41 having a constant width, and the inner peripheral portion is recessed by a certain amount, and a decorative skin 5 such as a nonwoven fabric or a fabric is attached to the inner peripheral portion. As shown in FIG. 8, the cross section of the seat frame 4 is formed by blow molding of a resin material to form a plurality of closed cross-section cylinder portions 42 extending in the horizontal direction at intervals in the vertical direction. The structural reinforcement is achieved by connecting the left and right vertical frames of the outer peripheral frame portion 41 having a cross section. As shown by the chain lines in FIGS. 7 and 8, a foam cushion member 6 is attached to such a seat frame 4 so as to cover the outer periphery and the front surface, thereby forming a rear seat back.
[0003]
Such a seat frame 4 is conventionally manufactured with dies 7 and 8 as shown in FIG. The figure shows a part of the mold surfaces of the molds 7 and 8 in cross section. The mold surface of the mold 7 is formed with irregularities along the outer shape of the seat frame 4, and the seat frame 4 A flat skin holding surface 81 is formed on the mold surface of the mold 8 corresponding to the inner peripheral portion of the rear surface, and the decorative skin 5 is held here in the mold open state. Then, a parison 4 ′ is supplied to the center of the molds 7 and 8 as shown in the figure, and after mold clamping, blow molding is performed.
[0004]
By the way, according to the above-described conventional mold, at the time of cooling after blow molding, there is a decorative skin 5 on the rear surface side of the seat frame 4, so that heat radiation does not proceed well, and the curing of the resin material is delayed with respect to the front surface side. There has been a problem that “curvature” occurs in the molded seat frame 4. In order to solve this problem, Japanese Patent Application Laid-Open No. 8-47965 discloses that the decorative skin 5 before being set in the mold is sprayed with water as shown in FIG. There has been proposed a method for preventing the occurrence of “warping” by promoting the cooling of the rear surface side of the seat frame 4 by the heat of vaporization and making the curing rate uniform with the front surface side of the seat frame.
[0005]
[Problems to be solved by the invention]
However, in the proposed method, a new process is required for spraying water on the decorative epidermis, and a space for that is required. Furthermore, the moisture adhered to the surface of the decorative skin wraps around or penetrates to the back side, which is the surface to be attached to the seat frame, while the decorative skin is set in the mold, and the seat frame and There was also a possibility that the adhesive strength of the resin may be lowered.
[0006]
The present invention solves the above-mentioned problems, does not require a watering step or watering space for the decorative skin, and further does not cause a decrease in the adhesive strength of the decorative skin to the blow molded product. And it aims at providing the blow molding method.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the gist of the invention described in claim 1 is that a skin holding surface (212) is formed on the mold surface of the mold (2), and the surface of the decorative skin (5) is held by the skin. A plurality of water supply holes (26) are formed in the skin holding surface (212), and the water supply holes (26) are formed in the mold (2). The blow molding die is characterized in that it is communicated with a water supply passage (24) provided in the blow molding die. A blow molding die according to a second aspect of the present invention is the blow molding mold according to the first aspect, wherein the water supply path of the first aspect is a water storage space (24) having a constant volume, and the water supply holes (26) are formed in the water storage space (24). Further, the water supply hole (26) is provided with a filter member (3) that covers the water supply hole (26).
[0008]
Further, the gist of the invention described in claim 3 is that the decorative skin is set on the skin holding surface using the blow molding die described in claim 1, and the water passing through the water supply holes is applied to the skin holding surface. The blow molding method is characterized in that it is wetted, and then the mold is closed and integrally molded with the decorative skin.
Here, in order to “make the moisture wet the skin holding surface”, when the skin holding surface is covered with the filter member, the case where moisture is held by the filter member is also considered to be applicable.
[0009]
As in the first and third aspects of the invention, when water is supplied from the water supply path to each water supply hole, moisture is given to the decorative skin held on the skin holding surface of the mold. Thereafter, when the parison is supplied into the mold and the mold is clamped and blow-molded, the decorative skin is joined to the blow-molded product. In the blow molding and demolding process, moisture contained in the decorative skin is vaporized, and cooling of the blow molded product surface joined to the decorative skin is promoted. As a result, the same heat dissipation as that of the blow-molded product surface to which the decorative skin is not bonded is achieved, the curing rates of both surfaces become substantially equal, and the molding cycle is shortened. At the same time, the problem of “warping” of the blow molded product is solved.
Furthermore, when moisture is supplied to the decorative skin within the mold, it is not necessary to separately perform a watering step for the decorative skin as in the prior art, and it is not necessary to newly secure a watering space.
In addition, since the blow molding can be performed immediately after the moisture supply to the decorative skin, the moisture does not penetrate into the joint surface of the decorative skin with the blow molded product, and the blow molded product and the decorative skin Bonding proceeds smoothly.
[0010]
If the water supply path is a fixed-volume water storage space as in the invention of claim 2, the water storage space plays a role of a distribution header to each water supply hole. Can supply.
In addition, when the filter member is provided, the water retention of the filter member is utilized, and since the retained water can be evenly dispersed, the back surface side, which is the attachment surface to the seat frame of the decorative skin It is possible to more reliably suppress the sneaking of water into the water, and to efficiently promote the cooling of the blow molded product surface on the side where the decorative skin is joined.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(1) Embodiment 1
1 to 3 show an embodiment of a blow molding die according to the present invention, and FIG. 1 is a perspective view thereof. In the figure, a mold 1 (hereinafter referred to as a front mold) that forms the front side (the left side in FIG. 8) of a seat frame 4 has basically the same structure as a conventional one (mold 7 in FIG. 9). is there. On the other hand, a mold 2 (hereinafter referred to as a rear mold) that forms the rear side (the right side in FIG. 8) of the seat frame 4 is divided into two in the thickness direction. , 22 are connected to each other by bolts (not shown) with a packing 23 interposed on the entire outer periphery of the abutting surface.
The mold surface of the split mold 21 that is directly brought into contact with the front mold 1 has an outer peripheral portion 211 recessed into a groove shape to form the frame portion 41 (FIG. 7) of the seat frame 4, and the inner peripheral portion is detailed. Is a flat skin holding surface 212 described later. The rear mold 22 is connected to a water supply pipe 31 at the lower end of the side surface and a water discharge pipe 32 at the upper end of the side surface.
[0012]
FIG. 2 shows a partial vertical sectional view of both molds 1 and 2, and FIG. 3 shows an overall horizontal sectional view of the rear mold 2. The split mold 21 of the rear mold 2 has a concave inner surface on the back side behind the skin holding surface 212, and the split mold 22 that abuts the split mold 21 also corresponds to the abutting surface. The area is recessed. As a result, when the two split molds 21 and 22 are joined to the outer periphery with the packing 23 interposed, a fixed volume of water storage space 24 (water supply path) is formed behind the skin holding surface 212. The water supply pipe 31 and the water discharge pipe 32 described above are connected to the water supply path 213 and the drainage path 214 formed in the split mold 21, respectively, and communicate with the water storage space 24.
[0013]
A large number of pins 25 are erected on the skin holding surface 212 of the split mold 21, and the decorative skin 5 is brought into contact with the surface by engaging the decorative skin 5 with these pins 25. It is held on the skin holding surface 212. Here, the decorative skin 5 refers to a skin such as a nonwoven fabric, a fabric, or a carpet having a design surface.
A plurality of (many) water supply holes 26 are formed in the skin holding surface 212 between the pins 25, and these water supply holes 26 pass through the split mold 21 and open into the water storage space 24. . The diameter of the water supply hole 26 is preferably as small as possible in view of the uniform dispersion of the decorative skin 5, and on the other hand, if the diameter is too small, clogging easily occurs. Is preferred. Of course, since the decorative skin 5 also has a dispersing action, even if the number of water supply holes is reduced and slightly increased, water can be uniformly supplied to the decorative skin 5.
By the way, when moisture permeates the back side of the decorative skin 5 that is joined to the seat frame 4, the strength of the joint decreases, so that the amount of water supplied spreads over the entire surface of the decorative skin 5 and is decorated. It is preferable that the moisture does not penetrate into the back surface side (parison side) of the skin 5. As an example of the water supply amount, when a carpet material is used as the decorative skin 5, 50 to 120 g / m ² is a preferable range. The adjustment of the water supply amount is performed by changing the water pressure in the water storage space 24 by adjusting the water amount of the water supply pipe 31. The water is constantly circulated through the water discharge pipe 32, cooled by a heat exchanger (not shown), and stored water is not excessively heated by heat transfer during blow molding. As a matter of course, the amount of moisture that wets the skin holding surface 212 through the water supply hole 26 is reduced from the amount of water supplied, so that the water is replenished accordingly.
[0014]
Next, a method of blow-molding the decorative outer skin-integrated seat frame 4 using the molds 1 and 2 having the above structure will be described.
First, in the mold open state, the front side of the decorative skin 5 is locked and held on the pin 25 of the skin holding surface 212 of the rear mold 2. Next, in the set state of the decorative skin 5, water is supplied from the water supply pipe 31 into the water storage space 24, and passes through the water supply hole 26 to the surface side of the decorative skin 5 in contact with the skin holding surface 212. Supply a predetermined amount of moisture.
After wetting the skin holding surface 212 with moisture, subsequently, the parison 4 'is suspended between the front mold 1 and the rear mold 2 as shown in FIG. Blow molding. At this time, the decorative skin 5 is thermally bonded to the rear surface of the blow-molded seat frame 4 (FIG. 4).
When the mold is removed after completion of molding, a desired blow molded product with a decorative decorative skin is obtained.
[0015]
According to the blow molding die and the blow molding method configured as described above, moisture can be supplied to the decorative skin 5 in a state where it is set in the die 2, so that water is sprayed on the decorative skin 5 as in the past. A new space or process is not required.
In addition, it is easy to control the water supply, and after the water supply, the parison 4 ′ can be immediately supplied and the mold can be quickly closed to shift to the molding of the seat frame 4. During the transition to the molding of the seat frame 4, there is no possibility that the moisture supplied to the front surface side of the decorative skin 5 will permeate the back surface side of the decorative skin 5 and reduce the bonding strength with the seat frame.
Thus, in the blow molding and demolding stages, moisture contained in the decorative skin 5 that has received heat during molding is vaporized to promote cooling of the rear side of the seat frame. Therefore, the curing rate on the rear side of the seat frame provided with the decorative skin 5 and the front side of the seat frame without the decorative skin 5 are almost equal, and the cooling time on the decorative skin side is rate-determining. It will be resolved. Furthermore, the heat-cooling balance is improved, and the occurrence of “warping” of the seat frame 4 after molding is prevented.
[0016]
(2) Embodiment 2
FIG. 5 shows a horizontal sectional view of the rear mold 2 of another embodiment. In the same figure, a plate-like filter member 3 is joined along the recessed surface side inner periphery of the split mold 2 to cover the mold surface side opening of each water supply hole 26. For the filter member 3, for example, an open-cell foam sheet is used. Specifically, open-cell foam made of polyvinyl chloride, polypropylene, polyethylene, polyurethane, various rubbers and the like is preferable. The filter member 3 only needs to be porous, and a nonwoven fabric, a net, a perforated plate, or the like can also be used. Since the filter member 3 is used in an upright state, the foaming ratio is changed in the vertical direction as necessary, and the filter member 3 is configured so that moisture adheres evenly to the decorative skin 5 as much as possible.
Further, the diameter of the water supply hole 26 is larger than that of the first embodiment. This is because the filter member has a function of dispersing water, and even when the diameter of the water supply hole 26 is increased, water can be evenly dispersed on the surface of the decorative skin 5. Other configurations are the same as those of the first embodiment.
A blow molding method using such a blow molding die is basically the same as in the first embodiment. However, when the moisture wets the skin holding surface 212, the filter member 3 has a water retention capability, and most of the moisture that wets the skin holding surface 212 tends to be absorbed by the filter member 3. Therefore, the moisture absorbed by the filter member 3 is added to determine the degree of wetting of the skin holding surface 212.
[0017]
In addition to the effects of the first embodiment, the blow molding die and the blow molding method configured as described above can increase the diameter of the water supply hole 26 in order to promote the water dispersing action of the filter member 3, and the mold cost can be increased. Not only is it cheaper, but the frequency of clogging of the water supply holes 26 is reduced. Therefore, maintenance is easy and stable blow molding can be ensured over a long period of time.
Furthermore, since the filter member 3 has a water retention capability, even if the skin holding surface 212 is wetted with moisture, the decorated skin 5 held by the filter member 3 is not so wet. For this reason, it is rare that water adheres to the decorative skin surface in contact with the parison 4 ', and blow molding integrated with the decorative skin 5 proceeds smoothly. In particular, at the time when the parison 4 'and the decorative skin 5 are bonded at the mold closing stage, most of the water is still held in the filter member 3, so that the water does not interfere with the parison 4' and the decoration. Adhesion of the skin 5 is perfect. When the mold closing is about to be completed, the filter member 3 is also squeezed, so that water is discharged. The timing of expelling this water is exactly the same as the timing at which cooling must be promoted, which is very convenient.
In addition, the decorative skin 5 is attached to the mold 2 in an upright state, but the conventional gazette technique (Japanese Patent Laid-Open No. 8-47965) uses the decorative skin 5 even if water is evenly sprayed on the decorative skin 5. While the water drips and becomes non-uniform while being set in the mold, in the present invention, the filter member 3 retains water to maintain uniform dispersion of water. It is of course also effective to supply water to the skin holding surface 212 after setting the decorative skin 5.
[0018]
(3) Embodiment 3
FIG. 6 shows a horizontal sectional view of the rear mold 2 of another embodiment. In the same figure, a plate-like filter member 3 is joined to the recessed inner surface of the back side of the split mold 21 so as to cover the water storage space side opening of each water supply hole 26. For the filter member 3, a foamed foam sheet or the like is used as described above.
Again, the diameter of the water supply hole 26 is larger than that of the first embodiment. This is because the filter member 3 increases the resistance of water and promotes the uniform and dispersing action of water by the porous shape. Further, here, the bubbles of the filter member 3 are fine at the lower part of the mold 2 (the other side of the sheet) and rough at the upper part of the mold 2 (the front side of the sheet). With such a structure, the diameter of the water supply hole 26 is substantially reduced due to the fine bubbles in the filter member 3 in the lower layer in the water storage space 24 where the water pressure is relatively high. The amount of water supplied to the decorative skin 5 can be made substantially uniform between the upper part and the upper part. Other configurations are the same as those of the first embodiment.
The blow molding method using such a blow molding die is basically the same as in the first embodiment.
In addition to the effects of the first embodiment, the blow molding die and the blow molding method configured in this way can increase the diameter of the water supply hole 26, reduce the mold cost, and clog the water supply hole 26. Therefore, stable blow molding can be secured over a long period of time.
[0019]
In addition, in this invention, it is not restricted to what is shown to the said embodiment, According to the objective and a use, it can change variously in the range of this invention. In each of the above embodiments, the water storage space 24 is formed in the rear mold 2 and water is distributed from the water storage space 24 to the water supply holes 26. However, the water storage space 24 is normally provided in the mold. It is also possible to distribute water from each cooling water channel to each water supply hole 26. A unique water supply path to each water supply hole 26 can also be provided. In the third embodiment, the diameter of the lower water supply hole 26 is substantially reduced by the filter member 3, but the actual diameter of the water supply hole 26 is made smaller toward the lower side of the mold 2 without using the filter member 3. Of course. By combining Embodiments 2 and 3, the filter member 3 can be disposed on both the front side inner peripheral part and the rear side inner peripheral part where the split mold 2 is recessed.
[0020]
【The invention's effect】
As described above, according to the blow molding die and the blow molding method of the present invention, the watering process and the watering space for the decorative skin are not required, and the adhesive strength of the decorative skin to the blow molded product is further reduced. It can be avoided and it is extremely useful.
[Brief description of the drawings]
FIG. 1 is a perspective view of a mold in a mold open state according to a first embodiment.
FIG. 2 is a partial vertical sectional view of a mold in a mold open state.
3 is a horizontal sectional view of a rear mold, and is a sectional view taken along line III-III in FIG.
FIG. 4 is an overall vertical sectional view of the mold in a clamped state.
5 is a horizontal sectional view of a rear mold according to Embodiment 2. FIG.
6 is a horizontal sectional view of a rear mold according to Embodiment 3. FIG.
FIG. 7 is an overall perspective view of a seat frame.
8 is a vertical sectional view of the seat frame, and is a sectional view taken along line VII-VII in FIG.
FIG. 9 is a partial vertical sectional view of a conventional mold.
FIG. 10 is a side view showing a watering process on the decorative skin.
[Explanation of symbols]
1, 2 Mold 212 Skin holding surface 24 Water storage space (water supply channel)
26 Water supply hole 3 Filter member 5 Decorated skin

Claims (3)

A skin holding surface (212) is formed on the mold surface of the mold (2) so that the decorative skin (5) can be held on the skin holding surface (212), and the skin holding surface (212) ), A plurality of water supply holes (26) are formed, and these water supply holes (26) communicate with a water supply path (24) provided in the mold (2). Mold. The water supply passage is defined as a fixed volume water storage space (24), the water supply holes (26) are communicated with the water storage space (24), and the water supply holes (26) are further connected to the water supply holes (26). The blow mold according to claim 1, wherein a filter member (3) for covering is provided. Using the blow mold according to claim 1, the decorative skin (5) is set on the skin holding surface (212), and the water passing through the water supply hole (26) causes the water on the skin holding surface (212). A blow molding method characterized in that it is wetted, and then the mold is closed and integrally molded with the decorative skin (5).

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