JPH0639107B2 - Seat back pad manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an automobile seat back pad, and more particularly, to a front side back pad portion that constitutes a backrest portion when seated, and the back pad portion. The present invention relates to a method for manufacturing a foamed polyurethane automobile seat back pad having different hardnesses on the front and back sides and having hard flange portions integrally formed on the back side of the vehicle and located on the upper side and the left and right sides.

[Prior Art] A cushion body in which a flange portion is integrally formed over the entire circumference on the back side of a back pad portion is disclosed in, for example, Japanese Patent Laid-Open No. 60-2.
No. 40414. However, this cushion body is integrally foam-molded by using the same polyurethane foam undiluted solution for both the back pad part and the flange part. Therefore, the back pad part is soft and the back flange part is hard. Absent.

That is, a hard seat flange is formed on the back side of the soft back pad to facilitate mounting on the frame, and the seat back pad for automobiles, which has a good backrest feeling when seated, is difficult to integrally mold in the past. In the end, the back pad part and the hard flange part are separately molded, and a manufacturing method is adopted in which they are integrated by adhesion in a later step.

In this case, in addition to requiring a separate mold, depending on the case, a separate manufacturing line is required, and a post-bonding step is also required, resulting in a problem of increasing manufacturing costs. Further, in the case of post-bonding, there is a concern that it may be peeled from the bonded part.

In the manufacture of a seat cushion that constitutes a seating surface instead of a seat back pad, a foam integrally molded product in which the seating surface and the back surface have different hardness has been conventionally disclosed.

For example, in Japanese Unexamined Patent Publication No. 61-182911, a high-hardness resin is foamed in a cavity of an upper mold by spraying to form a back surface portion, and then a soft resin is injected and foamed in a cavity of a lower surface to form a back surface. A seat back pad is disclosed in which the surface portion is formed integrally with the portion.

Further, in JP-A-62-73919, a method for producing a urethane foam stock solution by injecting a urethane foam stock solution into the upper mold and the lower mold by changing at least one of the compounding amount and the filling amount, and closing the upper mold and the lower mold during the foaming reaction. Is disclosed.

Further, Japanese Patent Application Laid-Open No. 48-28059 discloses a urethane foam cushion having both end portions having higher hardness than the central portion of the cushion body and having partially different cushion characteristics in the lateral direction.

[Problems to be Solved by the Invention] In the conventional example, the method of spraying the high hardness resin onto the upper die by spraying is performed in the seat cushion in which the high hardness back surface portion is integrally integrally formed with the front surface portion. Although it is possible, a seat back pad having different front and back hardnesses having a hard flange portion, which is the object of the present invention, cannot be implemented by a spray method because of problems of its shape and mechanical strength. In addition, the manufacturing method in which urethane foam stock solutions with different blending or filling amounts are injected into the upper mold and the upper mold and the lower mold are closed during the foaming reaction, the raw materials having a volume are injected into the upper mold and the lower mold, and the reaction occurs to some extent. If the mold is closed at the point when the hardness progresses and the hardness starts, it is presumed that it can be implemented as such. That is, in the case of the seat cushion that constitutes the seating surface, the volume is large and the shape is simple as compared with the hard flange portion of the seat back pad which is the subject of the present invention, and further, the mechanical strength at the joint surface is high. Since the strength is not required as much as when molding a hard flange part, the mold is closed when the reaction has progressed to the state where there is no risk of the raw material with a relatively large volume injected into the upper mold being separated from the upper mold when closing the mold. It is theoretically possible to adopt the manufacturing method in which the final foaming is performed integrally with the foaming material injected into the lower mold. However, when integrally forming the hard flange portion of the seat back pad, the applicability of this method is poor due to problems in molding and mechanical strength.

In addition, a conventional example disclosing a method for forming a cushion body having a different hardness portion in the lateral direction can also be used in a molded product having a simple shape and having a considerable volume, and its feasibility can be seen. It is considered impossible to carry out the molding of the hard flange portion of the seat back pad, which is the subject of the invention. Because of this state of the art,
Although the method of manufacturing a seat back pad having a hard flange portion on the back side is still based on the method of post-adhesion, the method of integral foam molding is preferable in terms of the strength of the molded product, and it is rich in mass productivity and can be manufactured. Since it is rich in various merits such as cost reduction, it has been strongly desired to implement it. Therefore, an object of the present invention is to provide a front surface side back pad portion that constitutes a backrest portion when seated and a hard flange portion integrally formed on the back side of the back pad portion on three sides of upper and left and right sides. In the manufacture of a foamed polyurethane automobile seat back pad with different front and back hardness,
It is about to achieve the implementation of the integral molding method.

[Means for Solving the Problems] As a result of earnest studies for achieving the above-mentioned object, it was made possible to implement a desired integral molding method by improving a molding die and a cavity structure.

That is, first, in the present invention, a forming die having a three-part structure of an upper die, a middle die, and a lower die is adopted as a forming die to be used. That is, the lower die for forming the back pad portion, the upper die that can be opened to the lower die in the expanded state, and the middle die that is set in the upper die and is provided in the opening direction from the inner surface of the upper die. A three-part mold is used.

Then, a cavity for molding the hard flange portion is formed between the middle mold and the inner surface of the upper mold, and in the opened state of the upper mold in which the middle mold is set, the polyurethane foam stock solution forming the back pad portion is injected into the lower mold. Injecting the polyurethane raw material for molding the hard flange into the cavity formed between the middle mold and the inner surface of the upper mold, and closing the mold during the foaming of both polyurethane foam raw liquids, depending on the middle and lower molds and the middle and upper molds. The back pad portion and the hard flange portion are molded, and a molding method for integrating the both is adopted.

The polyurethane foam undiluted solution forming the back pad portion and the polyurethane undiluted solution forming the hard flange portion are made to have different compositions so that desired hardness is imparted to each.

Further, the developed state of the upper mold with respect to the lower mold is set in the range of about 135 ° to 180 ° according to the raw material used.

[Operation] As described above, the upper mold that can be opened in the expanded state is provided for the lower mold for forming the back pad, and the middle mold is set to this upper mold.
Since the cavity for molding the hard flange portion is formed between the middle mold and the inner surface of the upper mold, in the state where the upper mold is opened to the expanded state, the polyurethane foam raw liquid for molding the hard flange portion is injected into the cavity. If foamed, the desired hard flange portion can be easily molded.

Further, when the predetermined polyurethane foam raw material solution is poured into this hard flange molding cavity, at the same time, the foamed polyurethane stock solution constituting the back pad portion can be poured into the lower mold to foam, and the foam for molding the hard flange portion can be formed. If the upper mold is closed during the foaming of the polyurethane stock solution to reach the final foam molding stage, the back pad part and the hard flange part will be molded simultaneously by the middle mold and the lower mold, and the middle mold and the upper mold, respectively. It is possible to manufacture a completely integrated product of a foamed polyurethane automobile seat back pad having different hardnesses on the front and back sides, in which the back pad portion and the hard flange portion are completely integrated and the back surface has a high hardness hard flange portion.

Since the hard flange is foam-molded in the cavity formed by the inner surface of the upper mold and the middle mold, the mold is closed in the foaming progress situation to the extent that sufficient bonding strength with the back pad is obtained in the final foam molding stage after mold closing. Even if the mold is closed, the polyurethane undiluted solution in the process of foaming that constitutes the hard flange does not come off, and the mold can be closed easily and reliably, and integral molding after closing the mold can be surely achieved under favorable foaming conditions. Is.

Embodiments Embodiments shown in the accompanying drawings will be described in detail below.

FIG. 1 is a side view showing a schematic structure of a three-part molding die used to carry out a method of manufacturing a seat back pad according to the present invention and its usage state. A raw polyurethane foam solution 4 for molding the back pad portion 3 (see FIG. 3) is injected from the main head 5 in the lower mold installed in the. 6 is
An upper mold that can be opened about 170 degrees to this lower mold,
Reference numeral 7 denotes a middle die set in the upper die 6 and movably provided in an opening direction from the inner surface of the upper die 6, and forms a hard flange portion 8 (see FIG. 3) between the inner die and the inner surface of the upper die 6. And a second cavity in this cavity.
The polyurethane foam stock solution 10 for molding the hard flange portion 8 is injected from the injection head 9 of FIG.

In this embodiment, when injecting the polyurethane foam undiluted solution 10 for molding the hard flange portion into the cavity formed by the upper mold 6 and the middle mold 7, the tapered surface 6a formed at the peripheral edge of the opening of the upper mold 6 is used. The method of pouring in is adopted. That is, the hard flange portion 8 is formed integrally on the back side of the back pad portion 3 on the upper side and the left and right sides, and the injection head 9 is moved along these three sides while injecting. Instead, it is devised so that the polyurethane foam stock solution 10 can be uniformly and quickly spread in the cavity. Also, with such a configuration, the injection head for the undiluted polyurethane foam solution has the second
In the figure, it is sufficient if it is within the permissible range indicated by reference numeral (a), and it also has an advantage that injection becomes easy.

In addition, in this embodiment, in order to make the hardness of the central seating portion 3a of the back pad portion 3 different from that of the raised portions 3b on both sides, the foamed polyurethane undiluted solution to be injected into the lower mold 1 is the same as the undiluted solution to be injected into the lower mold center. The composition is changed in the undiluted solution to be injected into the part, so that the injection into the lower mold is a two-stage shot.

In addition to the injection operation, the molding process and the timing of closing the mold are additionally described, for example, as follows.
That is, in a state where the upper mold 6 is opened to the lower mold 1 in an expanded state of about 170 °, the main head 5 and the injection are respectively injected into the central portion 1a of the lower mold 1 and the cavity formed by the upper mold inner surface and the middle mold 7. A corresponding polyurethane foam stock solution is injected from the head 9. In this state, it is left for about 8 seconds, for example, and then a polyurethane foam stock solution corresponding to both side portions 1b of the lower mold 1 is injected from another head. This state is maintained for about 10 seconds and the mold closing is started. It takes about 10 seconds to complete the mold closing. After closing the mold, the molding is completed in the heating furnace. The middle mold is fixed to the upper mold throughout the molding process. After the molding is completed, if the upper mold is opened, the hard flange portion holds the middle mold and the entire molded product can be taken out from the lower mold. Then, if the hard flange portion is removed from the middle mold, the final product shown in Fig. 3 can be obtained. Is obtained. Since the middle die is movably provided in the opening direction with respect to the upper die, when removing the product from the middle die, the middle die can be easily removed by detaching the middle die from the upper die. Incidentally, reference numeral 11 shown in FIG. 1 is a medium-sized fixing means, and by loosening the tightening means 11a, the middle die is movable in the opening direction from the inner surface of the upper die. After the completion of molding in the heating furnace, this tightening means 11a
If the upper mold is opened after slackening, the molded product can be immediately removed because it can be moved in the opening direction by its own weight while the molded product is held in the middle mold.

Incidentally, the timing of the injection of the foamed polyurethane stock solution,
The mold closing timing and the like are of course changed depending on the composition of the foamed polyurethane stock solution used, and the above is merely a representative example.

[Effects of the Invention] As described above, the present invention is capable of manufacturing a seat back pad having a hard flange portion, which has been inevitably manufactured by post-bonding after separate molding, by integral foam molding. There is a great contribution to the relevant technical field.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic structure of a molding die used for carrying out the method for manufacturing a seat back pad according to the present invention and its usage state, and is shown in a partial cross section. FIG. 2 is a schematic cross-sectional view showing a molding die and a molding state after the mold is closed, and FIG. 3 is an external perspective view showing an example of a molded product as seen from the back surface direction. 1 ... Lower mold, 3 ... Back pad part 4 ... Polyurethane foam undiluted solution 5 ... Main head, 6 ... Upper mold 7 ... Medium size, 8 ... Hard flange part 9 ... Injection head 10 ... Foamed polyurethane Undiluted solution

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location B29K 105: 04 B29L 31:58 4F (72) Inventor Ryo Kato 982 Kaneda, Atsugi, Kanagawa Toyo Sofran (72) Inventor Takenori Hiramoto 982 Kaneda, Atsugi, Kanagawa Toyoso Franc Co., Ltd. (72) Inventor Haruo Kawada 982, Kaneda, Atsugi, Kanagawa Toyoso Franc Co. (72) Inventor, Kikuo Sekida Kanagawa Toyo Sofran Co., Ltd. 982 Kaneda, Atsugi-shi, Japan

Claims (1)

[Claims] 1. A front-side back pad portion that constitutes a backrest portion when seated, and hard flange portions integrally formed on the back side of the back pad portion on three sides, that is, on the upper side and on the left and right sides, and have different front and back hardnesses. In a method for manufacturing a foamed polyurethane automobile seat back pad, a lower mold for molding a back pad portion, an upper mold that can be opened to the lower mold in a deployed state, and a top mold that is set in the upper mold and separated from the inner surface of the upper mold. In the open state of the upper mold with the middle mold set, a cavity for molding the hard flange portion is formed between the middle mold and the inner surface of the upper mold by using a molding mold having a three-part structure movably provided in the direction A polyurethane foam liquid for forming the back pad portion is injected into the lower mold, and a polyurethane resin for molding the hard flange portion is formed in the cavity formed between the middle mold and the inner surface of the upper mold. Injecting the stock solution, closing the molds during the foaming of both polyurethane foam stock solutions, forming the back pad part and the hard flange part by the middle mold and the lower mold, and the middle mold and the upper mold, and integrating them. A method for manufacturing an automobile seed back pad, comprising: